Merge remote-tracking branch 'upstream/master' into colorcolchar

21 files changed, 3069 insertions, 1902 deletions

diff --git a/src/nvim/eval/buffer.c b/src/nvim/eval/buffer.c
new file mode 100644
index 0000000000..2f37d1ba2e
--- /dev/null
+++ b/src/nvim/eval/buffer.c
@@ -0,0 +1,734 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
+// eval/buffer.c: Buffer related builtin functions
+
+#include <stdbool.h>
+#include <string.h>
+
+#include "nvim/ascii.h"
+#include "nvim/autocmd.h"
+#include "nvim/buffer.h"
+#include "nvim/buffer_defs.h"
+#include "nvim/change.h"
+#include "nvim/cursor.h"
+#include "nvim/eval.h"
+#include "nvim/eval/buffer.h"
+#include "nvim/eval/funcs.h"
+#include "nvim/eval/typval.h"
+#include "nvim/eval/typval_defs.h"
+#include "nvim/globals.h"
+#include "nvim/macros.h"
+#include "nvim/memline.h"
+#include "nvim/memory.h"
+#include "nvim/move.h"
+#include "nvim/path.h"
+#include "nvim/pos.h"
+#include "nvim/sign.h"
+#include "nvim/types.h"
+#include "nvim/undo.h"
+#include "nvim/vim.h"
+
+typedef struct {
+  win_T *cob_curwin_save;
+  aco_save_T cob_aco;
+  int cob_using_aco;
+  int cob_save_VIsual_active;
+} cob_T;
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "eval/buffer.c.generated.h"
+#endif
+
+/// Find a buffer by number or exact name.
+buf_T *find_buffer(typval_T *avar)
+{
+  buf_T *buf = NULL;
+
+  if (avar->v_type == VAR_NUMBER) {
+    buf = buflist_findnr((int)avar->vval.v_number);
+  } else if (avar->v_type == VAR_STRING && avar->vval.v_string != NULL) {
+    buf = buflist_findname_exp(avar->vval.v_string);
+    if (buf == NULL) {
+      // No full path name match, try a match with a URL or a "nofile"
+      // buffer, these don't use the full path.
+      FOR_ALL_BUFFERS(bp) {
+        if (bp->b_fname != NULL
+            && (path_with_url(bp->b_fname) || bt_nofilename(bp))
+            && strcmp(bp->b_fname, avar->vval.v_string) == 0) {
+          buf = bp;
+          break;
+        }
+      }
+    }
+  }
+  return buf;
+}
+
+/// If there is a window for "curbuf", make it the current window.
+static void find_win_for_curbuf(void)
+{
+  wininfo_T *wip;
+
+  // The b_wininfo list should have the windows that recently contained the
+  // buffer, going over this is faster than going over all the windows.
+  // Do check the buffer is still there.
+  FOR_ALL_BUF_WININFO(curbuf, wip) {
+    if (wip->wi_win != NULL && wip->wi_win->w_buffer == curbuf) {
+      curwin = wip->wi_win;
+      break;
+    }
+  }
+}
+
+/// Used before making a change in "buf", which is not the current one: Make
+/// "buf" the current buffer and find a window for this buffer, so that side
+/// effects are done correctly (e.g., adjusting marks).
+///
+/// Information is saved in "cob" and MUST be restored by calling
+/// change_other_buffer_restore().
+static void change_other_buffer_prepare(cob_T *cob, buf_T *buf)
+{
+  CLEAR_POINTER(cob);
+
+  // Set "curbuf" to the buffer being changed.  Then make sure there is a
+  // window for it to handle any side effects.
+  cob->cob_save_VIsual_active = VIsual_active;
+  VIsual_active = false;
+  cob->cob_curwin_save = curwin;
+  curbuf = buf;
+  find_win_for_curbuf();  // simplest: find existing window for "buf"
+
+  if (curwin->w_buffer != buf) {
+    // No existing window for this buffer.  It is dangerous to have
+    // curwin->w_buffer differ from "curbuf", use the autocmd window.
+    curbuf = curwin->w_buffer;
+    aucmd_prepbuf(&cob->cob_aco, buf);
+    cob->cob_using_aco = true;
+  }
+}
+
+static void change_other_buffer_restore(cob_T *cob)
+{
+  if (cob->cob_using_aco) {
+    aucmd_restbuf(&cob->cob_aco);
+  } else {
+    curwin = cob->cob_curwin_save;
+    curbuf = curwin->w_buffer;
+  }
+  VIsual_active = cob->cob_save_VIsual_active;
+}
+
+/// Set line or list of lines in buffer "buf" to "lines".
+/// Any type is allowed and converted to a string.
+static void set_buffer_lines(buf_T *buf, linenr_T lnum_arg, bool append, typval_T *lines,
+                             typval_T *rettv)
+  FUNC_ATTR_NONNULL_ARG(4, 5)
+{
+  linenr_T lnum = lnum_arg + (append ? 1 : 0);
+  long added = 0;
+
+  // When using the current buffer ml_mfp will be set if needed.  Useful when
+  // setline() is used on startup.  For other buffers the buffer must be
+  // loaded.
+  const bool is_curbuf = buf == curbuf;
+  if (buf == NULL || (!is_curbuf && buf->b_ml.ml_mfp == NULL) || lnum < 1) {
+    rettv->vval.v_number = 1;  // FAIL
+    return;
+  }
+
+  // After this don't use "return", goto "cleanup"!
+  cob_T cob;
+  if (!is_curbuf) {
+    // set "curbuf" to "buf" and find a window for this buffer
+    change_other_buffer_prepare(&cob, buf);
+  }
+
+  linenr_T append_lnum;
+  if (append) {
+    // appendbufline() uses the line number below which we insert
+    append_lnum = lnum - 1;
+  } else {
+    // setbufline() uses the line number above which we insert, we only
+    // append if it's below the last line
+    append_lnum = curbuf->b_ml.ml_line_count;
+  }
+
+  list_T *l = NULL;
+  listitem_T *li = NULL;
+  char *line = NULL;
+  if (lines->v_type == VAR_LIST) {
+    l = lines->vval.v_list;
+    if (l == NULL || tv_list_len(l) == 0) {
+      // set proper return code
+      if (lnum > curbuf->b_ml.ml_line_count) {
+        rettv->vval.v_number = 1;       // FAIL
+      }
+      goto cleanup;
+    }
+    li = tv_list_first(l);
+  } else {
+    line = typval_tostring(lines, false);
+  }
+
+  // Default result is zero == OK.
+  for (;;) {
+    if (lines->v_type == VAR_LIST) {
+      // List argument, get next string.
+      if (li == NULL) {
+        break;
+      }
+      xfree(line);
+      line = typval_tostring(TV_LIST_ITEM_TV(li), false);
+      li = TV_LIST_ITEM_NEXT(l, li);
+    }
+
+    rettv->vval.v_number = 1;  // FAIL
+    if (line == NULL || lnum > curbuf->b_ml.ml_line_count + 1) {
+      break;
+    }
+
+    // When coming here from Insert mode, sync undo, so that this can be
+    // undone separately from what was previously inserted.
+    if (u_sync_once == 2) {
+      u_sync_once = 1;  // notify that u_sync() was called
+      u_sync(true);
+    }
+
+    if (!append && lnum <= curbuf->b_ml.ml_line_count) {
+      // Existing line, replace it.
+      int old_len = (int)strlen(ml_get(lnum));
+      if (u_savesub(lnum) == OK
+          && ml_replace(lnum, line, true) == OK) {
+        inserted_bytes(lnum, 0, old_len, (int)strlen(line));
+        if (is_curbuf && lnum == curwin->w_cursor.lnum) {
+          check_cursor_col();
+        }
+        rettv->vval.v_number = 0;  // OK
+      }
+    } else if (added > 0 || u_save(lnum - 1, lnum) == OK) {
+      // append the line.
+      added++;
+      if (ml_append(lnum - 1, line, 0, false) == OK) {
+        rettv->vval.v_number = 0;  // OK
+      }
+    }
+
+    if (l == NULL) {  // only one string argument
+      break;
+    }
+    lnum++;
+  }
+  xfree(line);
+
+  if (added > 0) {
+    appended_lines_mark(append_lnum, added);
+
+    // Only adjust the cursor for buffers other than the current, unless it
+    // is the current window. For curbuf and other windows it has been done
+    // in mark_adjust_internal().
+    FOR_ALL_TAB_WINDOWS(tp, wp) {
+      if (wp->w_buffer == buf
+          && (wp->w_buffer != curbuf || wp == curwin)
+          && wp->w_cursor.lnum > append_lnum) {
+        wp->w_cursor.lnum += (linenr_T)added;
+      }
+    }
+    check_cursor_col();
+    update_topline(curwin);
+  }
+
+cleanup:
+  if (!is_curbuf) {
+    change_other_buffer_restore(&cob);
+  }
+}
+
+/// "append(lnum, string/list)" function
+void f_append(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  const int did_emsg_before = did_emsg;
+  const linenr_T lnum = tv_get_lnum(&argvars[0]);
+  if (did_emsg == did_emsg_before) {
+    set_buffer_lines(curbuf, lnum, true, &argvars[1], rettv);
+  }
+}
+
+/// Set or append lines to a buffer.
+static void buf_set_append_line(typval_T *argvars, typval_T *rettv, bool append)
+{
+  const int did_emsg_before = did_emsg;
+  buf_T *const buf = tv_get_buf(&argvars[0], false);
+  if (buf == NULL) {
+    rettv->vval.v_number = 1;  // FAIL
+  } else {
+    const linenr_T lnum = tv_get_lnum_buf(&argvars[1], buf);
+    if (did_emsg == did_emsg_before) {
+      set_buffer_lines(buf, lnum, append, &argvars[2], rettv);
+    }
+  }
+}
+
+/// "appendbufline(buf, lnum, string/list)" function
+void f_appendbufline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  buf_set_append_line(argvars, rettv, true);
+}
+
+/// "bufadd(expr)" function
+void f_bufadd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  char *name = (char *)tv_get_string(&argvars[0]);
+
+  rettv->vval.v_number = buflist_add(*name == NUL ? NULL : name, 0);
+}
+
+/// "bufexists(expr)" function
+void f_bufexists(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  rettv->vval.v_number = (find_buffer(&argvars[0]) != NULL);
+}
+
+/// "buflisted(expr)" function
+void f_buflisted(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  buf_T *buf;
+
+  buf = find_buffer(&argvars[0]);
+  rettv->vval.v_number = (buf != NULL && buf->b_p_bl);
+}
+
+/// "bufload(expr)" function
+void f_bufload(typval_T *argvars, typval_T *unused, EvalFuncData fptr)
+{
+  buf_T *buf = get_buf_arg(&argvars[0]);
+
+  if (buf != NULL) {
+    buffer_ensure_loaded(buf);
+  }
+}
+
+/// "bufloaded(expr)" function
+void f_bufloaded(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  buf_T *buf;
+
+  buf = find_buffer(&argvars[0]);
+  rettv->vval.v_number = (buf != NULL && buf->b_ml.ml_mfp != NULL);
+}
+
+/// "bufname(expr)" function
+void f_bufname(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  const buf_T *buf;
+  rettv->v_type = VAR_STRING;
+  rettv->vval.v_string = NULL;
+  if (argvars[0].v_type == VAR_UNKNOWN) {
+    buf = curbuf;
+  } else {
+    buf = tv_get_buf_from_arg(&argvars[0]);
+  }
+  if (buf != NULL && buf->b_fname != NULL) {
+    rettv->vval.v_string = xstrdup(buf->b_fname);
+  }
+}
+
+/// "bufnr(expr)" function
+void f_bufnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  const buf_T *buf;
+  bool error = false;
+
+  rettv->vval.v_number = -1;
+
+  if (argvars[0].v_type == VAR_UNKNOWN) {
+    buf = curbuf;
+  } else {
+    // Don't use tv_get_buf_from_arg(); we continue if the buffer wasn't found
+    // and the second argument isn't zero, but we want to return early if the
+    // first argument isn't a string or number so only one error is shown.
+    if (!tv_check_str_or_nr(&argvars[0])) {
+      return;
+    }
+    emsg_off++;
+    buf = tv_get_buf(&argvars[0], false);
+    emsg_off--;
+  }
+
+  // If the buffer isn't found and the second argument is not zero create a
+  // new buffer.
+  const char *name;
+  if (buf == NULL
+      && argvars[1].v_type != VAR_UNKNOWN
+      && tv_get_number_chk(&argvars[1], &error) != 0
+      && !error
+      && (name = tv_get_string_chk(&argvars[0])) != NULL) {
+    buf = buflist_new((char *)name, NULL, 1, 0);
+  }
+
+  if (buf != NULL) {
+    rettv->vval.v_number = buf->b_fnum;
+  }
+}
+
+static void buf_win_common(typval_T *argvars, typval_T *rettv, bool get_nr)
+{
+  const buf_T *const buf = tv_get_buf_from_arg(&argvars[0]);
+  if (buf == NULL) {  // no need to search if invalid arg or buffer not found
+    rettv->vval.v_number = -1;
+    return;
+  }
+
+  int winnr = 0;
+  int winid;
+  bool found_buf = false;
+  FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
+    winnr++;
+    if (wp->w_buffer == buf) {
+      found_buf = true;
+      winid = wp->handle;
+      break;
+    }
+  }
+  rettv->vval.v_number = (found_buf ? (get_nr ? winnr : winid) : -1);
+}
+
+/// "bufwinid(nr)" function
+void f_bufwinid(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  buf_win_common(argvars, rettv, false);
+}
+
+/// "bufwinnr(nr)" function
+void f_bufwinnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  buf_win_common(argvars, rettv, true);
+}
+
+/// "deletebufline()" function
+void f_deletebufline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  const int did_emsg_before = did_emsg;
+  rettv->vval.v_number = 1;   // FAIL by default
+  buf_T *const buf = tv_get_buf(&argvars[0], false);
+  if (buf == NULL) {
+    return;
+  }
+
+  linenr_T last;
+  const linenr_T first = tv_get_lnum_buf(&argvars[1], buf);
+  if (did_emsg > did_emsg_before) {
+    return;
+  }
+  if (argvars[2].v_type != VAR_UNKNOWN) {
+    last = tv_get_lnum_buf(&argvars[2], buf);
+  } else {
+    last = first;
+  }
+
+  if (buf->b_ml.ml_mfp == NULL || first < 1
+      || first > buf->b_ml.ml_line_count || last < first) {
+    return;
+  }
+
+  // After this don't use "return", goto "cleanup"!
+  const bool is_curbuf = buf == curbuf;
+  cob_T cob;
+  if (!is_curbuf) {
+    // set "curbuf" to "buf" and find a window for this buffer
+    change_other_buffer_prepare(&cob, buf);
+  }
+
+  if (last > curbuf->b_ml.ml_line_count) {
+    last = curbuf->b_ml.ml_line_count;
+  }
+  const long count = last - first + 1;
+
+  // When coming here from Insert mode, sync undo, so that this can be
+  // undone separately from what was previously inserted.
+  if (u_sync_once == 2) {
+    u_sync_once = 1;  // notify that u_sync() was called
+    u_sync(true);
+  }
+
+  if (u_save(first - 1, last + 1) == FAIL) {
+    goto cleanup;
+  }
+
+  for (linenr_T lnum = first; lnum <= last; lnum++) {
+    ml_delete(first, true);
+  }
+
+  FOR_ALL_TAB_WINDOWS(tp, wp) {
+    if (wp->w_buffer == buf) {
+      if (wp->w_cursor.lnum > last) {
+        wp->w_cursor.lnum -= (linenr_T)count;
+      } else if (wp->w_cursor.lnum > first) {
+        wp->w_cursor.lnum = first;
+      }
+      if (wp->w_cursor.lnum > wp->w_buffer->b_ml.ml_line_count) {
+        wp->w_cursor.lnum = wp->w_buffer->b_ml.ml_line_count;
+      }
+    }
+  }
+  check_cursor_col();
+  deleted_lines_mark(first, count);
+  rettv->vval.v_number = 0;  // OK
+
+cleanup:
+  if (!is_curbuf) {
+    change_other_buffer_restore(&cob);
+  }
+}
+
+/// @return  buffer options, variables and other attributes in a dictionary.
+static dict_T *get_buffer_info(buf_T *buf)
+{
+  dict_T *const dict = tv_dict_alloc();
+
+  tv_dict_add_nr(dict, S_LEN("bufnr"), buf->b_fnum);
+  tv_dict_add_str(dict, S_LEN("name"),
+                  buf->b_ffname != NULL ? (const char *)buf->b_ffname : "");
+  tv_dict_add_nr(dict, S_LEN("lnum"),
+                 buf == curbuf ? curwin->w_cursor.lnum : buflist_findlnum(buf));
+  tv_dict_add_nr(dict, S_LEN("linecount"), buf->b_ml.ml_line_count);
+  tv_dict_add_nr(dict, S_LEN("loaded"), buf->b_ml.ml_mfp != NULL);
+  tv_dict_add_nr(dict, S_LEN("listed"), buf->b_p_bl);
+  tv_dict_add_nr(dict, S_LEN("changed"), bufIsChanged(buf));
+  tv_dict_add_nr(dict, S_LEN("changedtick"), buf_get_changedtick(buf));
+  tv_dict_add_nr(dict, S_LEN("hidden"),
+                 buf->b_ml.ml_mfp != NULL && buf->b_nwindows == 0);
+
+  // Get a reference to buffer variables
+  tv_dict_add_dict(dict, S_LEN("variables"), buf->b_vars);
+
+  // List of windows displaying this buffer
+  list_T *const windows = tv_list_alloc(kListLenMayKnow);
+  FOR_ALL_TAB_WINDOWS(tp, wp) {
+    if (wp->w_buffer == buf) {
+      tv_list_append_number(windows, (varnumber_T)wp->handle);
+    }
+  }
+  tv_dict_add_list(dict, S_LEN("windows"), windows);
+
+  if (buf->b_signlist != NULL) {
+    // List of signs placed in this buffer
+    tv_dict_add_list(dict, S_LEN("signs"), get_buffer_signs(buf));
+  }
+
+  tv_dict_add_nr(dict, S_LEN("lastused"), buf->b_last_used);
+
+  return dict;
+}
+
+/// "getbufinfo()" function
+void f_getbufinfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  buf_T *argbuf = NULL;
+  bool filtered = false;
+  bool sel_buflisted = false;
+  bool sel_bufloaded = false;
+  bool sel_bufmodified = false;
+
+  tv_list_alloc_ret(rettv, kListLenMayKnow);
+
+  // List of all the buffers or selected buffers
+  if (argvars[0].v_type == VAR_DICT) {
+    dict_T *sel_d = argvars[0].vval.v_dict;
+
+    if (sel_d != NULL) {
+      dictitem_T *di;
+
+      filtered = true;
+
+      di = tv_dict_find(sel_d, S_LEN("buflisted"));
+      if (di != NULL && tv_get_number(&di->di_tv)) {
+        sel_buflisted = true;
+      }
+
+      di = tv_dict_find(sel_d, S_LEN("bufloaded"));
+      if (di != NULL && tv_get_number(&di->di_tv)) {
+        sel_bufloaded = true;
+      }
+      di = tv_dict_find(sel_d, S_LEN("bufmodified"));
+      if (di != NULL && tv_get_number(&di->di_tv)) {
+        sel_bufmodified = true;
+      }
+    }
+  } else if (argvars[0].v_type != VAR_UNKNOWN) {
+    // Information about one buffer.  Argument specifies the buffer
+    argbuf = tv_get_buf_from_arg(&argvars[0]);
+    if (argbuf == NULL) {
+      return;
+    }
+  }
+
+  // Return information about all the buffers or a specified buffer
+  FOR_ALL_BUFFERS(buf) {
+    if (argbuf != NULL && argbuf != buf) {
+      continue;
+    }
+    if (filtered && ((sel_bufloaded && buf->b_ml.ml_mfp == NULL)
+                     || (sel_buflisted && !buf->b_p_bl)
+                     || (sel_bufmodified && !buf->b_changed))) {
+      continue;
+    }
+
+    dict_T *const d = get_buffer_info(buf);
+    tv_list_append_dict(rettv->vval.v_list, d);
+    if (argbuf != NULL) {
+      return;
+    }
+  }
+}
+
+/// Get line or list of lines from buffer "buf" into "rettv".
+///
+/// @param retlist  if true, then the lines are returned as a Vim List.
+///
+/// @return  range (from start to end) of lines in rettv from the specified
+///          buffer.
+static void get_buffer_lines(buf_T *buf, linenr_T start, linenr_T end, int retlist, typval_T *rettv)
+{
+  rettv->v_type = (retlist ? VAR_LIST : VAR_STRING);
+  rettv->vval.v_string = NULL;
+
+  if (buf == NULL || buf->b_ml.ml_mfp == NULL || start < 0 || end < start) {
+    if (retlist) {
+      tv_list_alloc_ret(rettv, 0);
+    }
+    return;
+  }
+
+  if (retlist) {
+    if (start < 1) {
+      start = 1;
+    }
+    if (end > buf->b_ml.ml_line_count) {
+      end = buf->b_ml.ml_line_count;
+    }
+    tv_list_alloc_ret(rettv, end - start + 1);
+    while (start <= end) {
+      tv_list_append_string(rettv->vval.v_list,
+                            (const char *)ml_get_buf(buf, start++, false), -1);
+    }
+  } else {
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = ((start >= 1 && start <= buf->b_ml.ml_line_count)
+                            ? xstrdup(ml_get_buf(buf, start, false)) : NULL);
+  }
+}
+
+/// @param retlist  true: "getbufline()" function
+///                 false: "getbufoneline()" function
+static void getbufline(typval_T *argvars, typval_T *rettv, bool retlist)
+{
+  const int did_emsg_before = did_emsg;
+  buf_T *const buf = tv_get_buf_from_arg(&argvars[0]);
+  const linenr_T lnum = tv_get_lnum_buf(&argvars[1], buf);
+  if (did_emsg > did_emsg_before) {
+    return;
+  }
+  const linenr_T end = (argvars[2].v_type == VAR_UNKNOWN
+                        ? lnum
+                        : tv_get_lnum_buf(&argvars[2], buf));
+
+  get_buffer_lines(buf, lnum, end, retlist, rettv);
+}
+
+/// "getbufline()" function
+void f_getbufline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  getbufline(argvars, rettv, true);
+}
+
+/// "getbufoneline()" function
+void f_getbufoneline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  getbufline(argvars, rettv, false);
+}
+
+/// "getline(lnum, [end])" function
+void f_getline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  linenr_T end;
+  bool retlist;
+
+  const linenr_T lnum = tv_get_lnum(argvars);
+  if (argvars[1].v_type == VAR_UNKNOWN) {
+    end = lnum;
+    retlist = false;
+  } else {
+    end = tv_get_lnum(&argvars[1]);
+    retlist = true;
+  }
+
+  get_buffer_lines(curbuf, lnum, end, retlist, rettv);
+}
+
+/// "setbufline()" function
+void f_setbufline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  buf_set_append_line(argvars, rettv, false);
+}
+
+/// "setline()" function
+void f_setline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  const int did_emsg_before = did_emsg;
+  linenr_T lnum = tv_get_lnum(&argvars[0]);
+  if (did_emsg == did_emsg_before) {
+    set_buffer_lines(curbuf, lnum, false, &argvars[1], rettv);
+  }
+}
+
+/// Make "buf" the current buffer.
+///
+/// restore_buffer() MUST be called to undo.
+/// No autocommands will be executed. Use aucmd_prepbuf() if there are any.
+void switch_buffer(bufref_T *save_curbuf, buf_T *buf)
+{
+  block_autocmds();
+  set_bufref(save_curbuf, curbuf);
+  curbuf->b_nwindows--;
+  curbuf = buf;
+  curwin->w_buffer = buf;
+  curbuf->b_nwindows++;
+}
+
+/// Restore the current buffer after using switch_buffer().
+void restore_buffer(bufref_T *save_curbuf)
+{
+  unblock_autocmds();
+  // Check for valid buffer, just in case.
+  if (bufref_valid(save_curbuf)) {
+    curbuf->b_nwindows--;
+    curwin->w_buffer = save_curbuf->br_buf;
+    curbuf = save_curbuf->br_buf;
+    curbuf->b_nwindows++;
+  }
+}
+
+/// Find a window for buffer "buf".
+/// If found true is returned and "wp" and "tp" are set to
+/// the window and tabpage.
+/// If not found, false is returned.
+///
+/// @param       buf  buffer to find a window for
+/// @param[out]  wp   stores the found window
+/// @param[out]  tp   stores the found tabpage
+///
+/// @return  true if a window was found for the buffer.
+bool find_win_for_buf(buf_T *buf, win_T **wp, tabpage_T **tp)
+{
+  *wp = NULL;
+  *tp = NULL;
+  FOR_ALL_TAB_WINDOWS(tp2, wp2) {
+    if (wp2->w_buffer == buf) {
+      *tp = tp2;
+      *wp = wp2;
+      return true;
+    }
+  }
+  return false;
+}
diff --git a/src/nvim/eval/buffer.h b/src/nvim/eval/buffer.h
new file mode 100644
index 0000000000..4a2f8f9e94
--- /dev/null
+++ b/src/nvim/eval/buffer.h
@@ -0,0 +1,10 @@
+#ifndef NVIM_EVAL_BUFFER_H
+#define NVIM_EVAL_BUFFER_H
+
+#include "nvim/buffer_defs.h"
+#include "nvim/eval/typval_defs.h"
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "eval/buffer.h.generated.h"
+#endif
+#endif  // NVIM_EVAL_BUFFER_H
diff --git a/src/nvim/eval/decode.c b/src/nvim/eval/decode.c
index 94ef419bed..cd1479f150 100644
--- a/src/nvim/eval/decode.c
+++ b/src/nvim/eval/decode.c
@@ -1,20 +1,31 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check
 // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
-#include <msgpack.h>
+#include <assert.h>
+#include <msgpack/object.h>
+#include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
 
 #include "klib/kvec.h"
 #include "nvim/ascii.h"
-#include "nvim/charset.h"  // vim_str2nr
+#include "nvim/charset.h"
 #include "nvim/eval.h"
 #include "nvim/eval/decode.h"
 #include "nvim/eval/encode.h"
 #include "nvim/eval/typval.h"
-#include "nvim/globals.h"
+#include "nvim/eval/typval_defs.h"
+#include "nvim/garray.h"
+#include "nvim/gettext.h"
+#include "nvim/hashtab.h"
 #include "nvim/macros.h"
+#include "nvim/mbyte.h"
+#include "nvim/memory.h"
 #include "nvim/message.h"
-#include "nvim/vim.h"  // OK, FAIL
+#include "nvim/types.h"
+#include "nvim/vim.h"
 
 /// Helper structure for container_struct
 typedef struct {
@@ -271,11 +282,9 @@ typval_T decode_string(const char *const s, const size_t len, const TriState has
       list_T *const list = tv_list_alloc(kListLenMayKnow);
       tv_list_ref(list);
       create_special_dict(&tv, kMPString,
-                          ((typval_T){
-        .v_type = VAR_LIST,
-        .v_lock = VAR_UNLOCKED,
-        .vval = { .v_list = list },
-      }));
+                          (typval_T){ .v_type = VAR_LIST,
+                                      .v_lock = VAR_UNLOCKED,
+                                      .vval = { .v_list = list } });
       const int elw_ret = encode_list_write((void *)list, s, len);
       if (s_allocated) {
         xfree((void *)s);
@@ -286,13 +295,12 @@ typval_T decode_string(const char *const s, const size_t len, const TriState has
       }
     }
     return tv;
-  } else {
-    return (typval_T) {
-      .v_type = VAR_STRING,
-      .v_lock = VAR_UNLOCKED,
-      .vval = { .v_string = ((s == NULL || s_allocated) ? (char *)s : xmemdupz(s, len)) },
-    };
   }
+  return (typval_T) {
+    .v_type = VAR_STRING,
+    .v_lock = VAR_UNLOCKED,
+    .vval = { .v_string = ((s == NULL || s_allocated) ? (char *)s : xmemdupz(s, len)) },
+  };
 }
 
 /// Parse JSON double-quoted string
@@ -368,7 +376,7 @@ static inline int parse_json_string(const char *const buf, const size_t buf_len,
         goto parse_json_string_fail;
       }
     } else {
-      uint8_t p_byte = (uint8_t)*p;
+      uint8_t p_byte = (uint8_t)(*p);
       // unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
       if (p_byte < 0x20) {
         semsg(_("E474: ASCII control characters cannot be present "
@@ -469,7 +477,7 @@ static inline int parse_json_string(const char *const buf, const size_t buf_len,
           ['r'] = CAR,
           ['f'] = FF,
         };
-        *str_end++ = escapes[(int)*t];
+        *str_end++ = escapes[(int)(*t)];
         break;
       }
       default:
@@ -838,12 +846,10 @@ json_decode_string_cycle_start:
         .v_lock = VAR_UNLOCKED,
         .vval = { .v_list = list },
       };
-      kv_push(container_stack, ((ContainerStackItem) {
-          .stack_index = kv_size(stack),
-          .s = p,
-          .container = tv,
-          .special_val = NULL,
-        }));
+      kv_push(container_stack, ((ContainerStackItem) { .stack_index = kv_size(stack),
+                                                       .s = p,
+                                                       .container = tv,
+                                                       .special_val = NULL }));
       kv_push(stack, OBJ(tv, false, didcomma, didcolon));
       break;
     }
@@ -862,12 +868,10 @@ json_decode_string_cycle_start:
           .vval = { .v_dict = dict },
         };
       }
-      kv_push(container_stack, ((ContainerStackItem) {
-          .stack_index = kv_size(stack),
-          .s = p,
-          .container = tv,
-          .special_val = val_list,
-        }));
+      kv_push(container_stack, ((ContainerStackItem) { .stack_index = kv_size(stack),
+                                                       .s = p,
+                                                       .container = tv,
+                                                       .special_val = val_list }));
       kv_push(stack, OBJ(tv, false, didcomma, didcolon));
       break;
     }
@@ -1089,11 +1093,9 @@ msgpack_to_vim_generic_map: {}
     tv_list_append_number(list, mobj.via.ext.type);
     list_T *const ext_val_list = tv_list_alloc(kListLenMayKnow);
     tv_list_append_list(list, ext_val_list);
-    create_special_dict(rettv, kMPExt, ((typval_T) {
-        .v_type = VAR_LIST,
-        .v_lock = VAR_UNLOCKED,
-        .vval = { .v_list = list },
-      }));
+    create_special_dict(rettv, kMPExt, ((typval_T) { .v_type = VAR_LIST,
+                                                     .v_lock = VAR_UNLOCKED,
+                                                     .vval = { .v_list = list } }));
     if (encode_list_write((void *)ext_val_list, mobj.via.ext.ptr,
                           mobj.via.ext.size) == -1) {
       return FAIL;
diff --git a/src/nvim/eval/encode.c b/src/nvim/eval/encode.c
index 27d35ea24f..c2f1eae8af 100644
--- a/src/nvim/eval/encode.c
+++ b/src/nvim/eval/encode.c
@@ -10,23 +10,28 @@
 #include <assert.h>
 #include <inttypes.h>
 #include <math.h>
-#include <msgpack.h>
+#include <stdbool.h>
 #include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
 
 #include "klib/kvec.h"
+#include "msgpack/pack.h"
 #include "nvim/ascii.h"
-#include "nvim/buffer_defs.h"
-#include "nvim/charset.h"  // vim_isprintc()
 #include "nvim/eval.h"
 #include "nvim/eval/encode.h"
 #include "nvim/eval/typval.h"
 #include "nvim/eval/typval_encode.h"
 #include "nvim/garray.h"
+#include "nvim/gettext.h"
+#include "nvim/hashtab.h"
 #include "nvim/macros.h"
 #include "nvim/math.h"
 #include "nvim/mbyte.h"
 #include "nvim/memory.h"
 #include "nvim/message.h"
+#include "nvim/strings.h"
+#include "nvim/types.h"
 #include "nvim/vim.h"  // For _()
 
 const char *const encode_bool_var_names[] = {
@@ -131,35 +136,35 @@ static int conv_error(const char *const msg, const MPConvStack *const mpstack,
       typval_T key_tv = {
         .v_type = VAR_STRING,
         .vval = { .v_string =
-                    (char *)(v.data.d.hi ==
-                             NULL ? v.data.d.dict->dv_hashtab.ht_array : (v.data.d.hi -
-                                                                          1))->hi_key },
+                    (v.data.d.hi ==
+                     NULL ? v.data.d.dict->dv_hashtab.ht_array : (v.data.d.hi -
+                                                                  1))->hi_key },
       };
       char *const key = encode_tv2string(&key_tv, NULL);
-      vim_snprintf((char *)IObuff, IOSIZE, key_msg, key);
+      vim_snprintf(IObuff, IOSIZE, key_msg, key);
       xfree(key);
-      ga_concat(&msg_ga, (char *)IObuff);
+      ga_concat(&msg_ga, IObuff);
       break;
     }
     case kMPConvPairs:
     case kMPConvList: {
       const int idx = (v.data.l.li == tv_list_first(v.data.l.list)
-                         ? 0
-                         : (v.data.l.li == NULL
-                            ? tv_list_len(v.data.l.list) - 1
-                            : (int)tv_list_idx_of_item(v.data.l.list,
-                                                       TV_LIST_ITEM_PREV(v.data.l.list,
-                                                                         v.data.l.li))));
+                       ? 0
+                       : (v.data.l.li == NULL
+                          ? tv_list_len(v.data.l.list) - 1
+                          : (int)tv_list_idx_of_item(v.data.l.list,
+                                                     TV_LIST_ITEM_PREV(v.data.l.list,
+                                                                       v.data.l.li))));
       const listitem_T *const li = (v.data.l.li == NULL
-                                      ? tv_list_last(v.data.l.list)
-                                      : TV_LIST_ITEM_PREV(v.data.l.list,
-                                                          v.data.l.li));
+                                    ? tv_list_last(v.data.l.list)
+                                    : TV_LIST_ITEM_PREV(v.data.l.list,
+                                                        v.data.l.li));
       if (v.type == kMPConvList
           || li == NULL
           || (TV_LIST_ITEM_TV(li)->v_type != VAR_LIST
               && tv_list_len(TV_LIST_ITEM_TV(li)->vval.v_list) <= 0)) {
-        vim_snprintf((char *)IObuff, IOSIZE, idx_msg, idx);
-        ga_concat(&msg_ga, (char *)IObuff);
+        vim_snprintf(IObuff, IOSIZE, idx_msg, idx);
+        ga_concat(&msg_ga, IObuff);
       } else {
         assert(li != NULL);
         listitem_T *const first_item =
@@ -167,9 +172,9 @@ static int conv_error(const char *const msg, const MPConvStack *const mpstack,
         assert(first_item != NULL);
         typval_T key_tv = *TV_LIST_ITEM_TV(first_item);
         char *const key = encode_tv2echo(&key_tv, NULL);
-        vim_snprintf((char *)IObuff, IOSIZE, key_pair_msg, key, idx);
+        vim_snprintf(IObuff, IOSIZE, key_pair_msg, key, idx);
         xfree(key);
-        ga_concat(&msg_ga, (char *)IObuff);
+        ga_concat(&msg_ga, IObuff);
       }
       break;
     }
@@ -188,8 +193,8 @@ static int conv_error(const char *const msg, const MPConvStack *const mpstack,
       break;
     case kMPConvPartialList: {
       const int idx = (int)(v.data.a.arg - v.data.a.argv) - 1;
-      vim_snprintf((char *)IObuff, IOSIZE, partial_arg_i_msg, idx);
-      ga_concat(&msg_ga, (char *)IObuff);
+      vim_snprintf(IObuff, IOSIZE, partial_arg_i_msg, idx);
+      ga_concat(&msg_ga, IObuff);
       break;
     }
     }
@@ -304,7 +309,7 @@ int encode_read_from_list(ListReaderState *const state, char *const buf, const s
         if (buf_[i_] == '\'') { \
           ga_append(gap, '\''); \
         } \
-        ga_append(gap, buf_[i_]); \
+        ga_append(gap, (uint8_t)buf_[i_]); \
       } \
       ga_append(gap, '\''); \
     } \
diff --git a/src/nvim/eval/encode.h b/src/nvim/eval/encode.h
index 8755ff48ac..41e7614fc0 100644
--- a/src/nvim/eval/encode.h
+++ b/src/nvim/eval/encode.h
@@ -2,11 +2,15 @@
 #define NVIM_EVAL_ENCODE_H
 
 #include <msgpack.h>
+#include <msgpack/pack.h>
 #include <stddef.h>
+#include <string.h>
 
 #include "nvim/eval.h"
+#include "nvim/eval/typval.h"
+#include "nvim/eval/typval_defs.h"
 #include "nvim/garray.h"
-#include "nvim/vim.h"  // For STRLEN
+#include "nvim/vim.h"
 
 /// Convert VimL value to msgpack string
 ///
@@ -15,9 +19,7 @@
 /// @param[in]  objname  Object name, used for error message.
 ///
 /// @return OK in case of success, FAIL otherwise.
-int encode_vim_to_msgpack(msgpack_packer *const packer,
-                          typval_T *const tv,
-                          const char *const objname);
+int encode_vim_to_msgpack(msgpack_packer *packer, typval_T *tv, const char *objname);
 
 /// Convert VimL value to :echo output
 ///
@@ -26,9 +28,7 @@ int encode_vim_to_msgpack(msgpack_packer *const packer,
 /// @param[in]  objname  Object name, used for error message.
 ///
 /// @return OK in case of success, FAIL otherwise.
-int encode_vim_to_echo(garray_T *const packer,
-                       typval_T *const tv,
-                       const char *const objname);
+int encode_vim_to_echo(garray_T *packer, typval_T *tv, const char *objname);
 
 /// Structure defining state for read_from_list()
 typedef struct {
@@ -48,7 +48,7 @@ static inline ListReaderState encode_init_lrstate(const list_T *const list)
     .offset = 0,
     .li_length = (TV_LIST_ITEM_TV(tv_list_first(list))->vval.v_string == NULL
                   ? 0
-                  : STRLEN(TV_LIST_ITEM_TV(tv_list_first(list))->vval.v_string)),
+                  : strlen(TV_LIST_ITEM_TV(tv_list_first(list))->vval.v_string)),
   };
 }
 
diff --git a/src/nvim/eval/executor.c b/src/nvim/eval/executor.c
index 0e0d0fe696..9caea2fef1 100644
--- a/src/nvim/eval/executor.c
+++ b/src/nvim/eval/executor.c
@@ -1,15 +1,23 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check
 // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
+#include <inttypes.h>
+#include <stdlib.h>
+
 #include "nvim/eval.h"
 #include "nvim/eval/executor.h"
 #include "nvim/eval/typval.h"
+#include "nvim/eval/typval_defs.h"
+#include "nvim/garray.h"
+#include "nvim/gettext.h"
 #include "nvim/globals.h"
 #include "nvim/message.h"
+#include "nvim/strings.h"
+#include "nvim/types.h"
 #include "nvim/vim.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
-# include "eval/executor.c.generated.h"
+# include "eval/executor.c.generated.h"  // IWYU pragma: export
 #endif
 
 char *e_listidx = N_("E684: list index out of range: %" PRId64);
@@ -43,7 +51,7 @@ int eexe_mod_op(typval_T *const tv1, const typval_T *const tv2, const char *cons
         blob_T *const b1 = tv1->vval.v_blob;
         blob_T *const b2 = tv2->vval.v_blob;
         for (int i = 0; i < tv_blob_len(b2); i++) {
-          ga_append(&b1->bv_ga, (char)tv_blob_get(b2, i));
+          ga_append(&b1->bv_ga, tv_blob_get(b2, i));
         }
       }
       return OK;
@@ -61,7 +69,7 @@ int eexe_mod_op(typval_T *const tv1, const typval_T *const tv2, const char *cons
       if (tv2->v_type == VAR_LIST) {
         break;
       }
-      if (vim_strchr("+-*/%", *op) != NULL) {
+      if (vim_strchr("+-*/%", (uint8_t)(*op)) != NULL) {
         // nr += nr  or  nr -= nr, nr *= nr, nr /= nr, nr %= nr
         varnumber_T n = tv_get_number(tv1);
         if (tv2->v_type == VAR_FLOAT) {
@@ -122,8 +130,8 @@ int eexe_mod_op(typval_T *const tv1, const typval_T *const tv2, const char *cons
         break;
       }
       const float_T f = (tv2->v_type == VAR_FLOAT
-                           ? tv2->vval.v_float
-                           : (float_T)tv_get_number(tv2));
+                         ? tv2->vval.v_float
+                         : (float_T)tv_get_number(tv2));
       switch (*op) {
       case '+':
         tv1->vval.v_float += f; break;
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index a326c44371..5a31288ecd 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -1,27 +1,44 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check
 // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
+#include <assert.h>
+#include <fcntl.h>
 #include <float.h>
+#include <inttypes.h>
+#include <limits.h>
 #include <math.h>
-
+#include <msgpack/object.h>
+#include <msgpack/pack.h>
+#include <msgpack/unpack.h>
+#include <signal.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <uv.h>
+
+#include "auto/config.h"
 #include "nvim/api/private/converter.h"
+#include "nvim/api/private/defs.h"
+#include "nvim/api/private/dispatch.h"
 #include "nvim/api/private/helpers.h"
 #include "nvim/api/vim.h"
-#include "nvim/arglist.h"
 #include "nvim/ascii.h"
 #include "nvim/assert.h"
+#include "nvim/autocmd.h"
 #include "nvim/buffer.h"
-#include "nvim/change.h"
+#include "nvim/buffer_defs.h"
 #include "nvim/channel.h"
 #include "nvim/charset.h"
 #include "nvim/cmdexpand.h"
-#include "nvim/cmdhist.h"
 #include "nvim/context.h"
 #include "nvim/cursor.h"
 #include "nvim/diff.h"
-#include "nvim/digraph.h"
 #include "nvim/edit.h"
 #include "nvim/eval.h"
+#include "nvim/eval/buffer.h"
 #include "nvim/eval/decode.h"
 #include "nvim/eval/encode.h"
 #include "nvim/eval/executor.h"
@@ -29,55 +46,72 @@
 #include "nvim/eval/typval.h"
 #include "nvim/eval/userfunc.h"
 #include "nvim/eval/vars.h"
+#include "nvim/eval/window.h"
+#include "nvim/event/loop.h"
+#include "nvim/event/multiqueue.h"
+#include "nvim/event/process.h"
+#include "nvim/event/time.h"
 #include "nvim/ex_cmds.h"
 #include "nvim/ex_docmd.h"
 #include "nvim/ex_eval.h"
 #include "nvim/ex_getln.h"
 #include "nvim/file_search.h"
 #include "nvim/fileio.h"
-#include "nvim/fold.h"
+#include "nvim/garray.h"
 #include "nvim/getchar.h"
+#include "nvim/gettext.h"
 #include "nvim/globals.h"
+#include "nvim/grid_defs.h"
+#include "nvim/hashtab.h"
+#include "nvim/highlight_defs.h"
 #include "nvim/highlight_group.h"
-#include "nvim/if_cscope.h"
 #include "nvim/indent.h"
 #include "nvim/indent_c.h"
 #include "nvim/input.h"
-#include "nvim/insexpand.h"
+#include "nvim/keycodes.h"
 #include "nvim/lua/executor.h"
 #include "nvim/macros.h"
-#include "nvim/mapping.h"
+#include "nvim/main.h"
 #include "nvim/mark.h"
-#include "nvim/match.h"
 #include "nvim/math.h"
+#include "nvim/mbyte.h"
+#include "nvim/memfile_defs.h"
 #include "nvim/memline.h"
+#include "nvim/memory.h"
 #include "nvim/menu.h"
+#include "nvim/message.h"
 #include "nvim/mouse.h"
 #include "nvim/move.h"
 #include "nvim/msgpack_rpc/channel.h"
+#include "nvim/msgpack_rpc/channel_defs.h"
 #include "nvim/msgpack_rpc/server.h"
+#include "nvim/normal.h"
 #include "nvim/ops.h"
 #include "nvim/option.h"
 #include "nvim/optionstr.h"
 #include "nvim/os/dl.h"
+#include "nvim/os/fileio.h"
+#include "nvim/os/fs_defs.h"
+#include "nvim/os/os.h"
+#include "nvim/os/pty_process.h"
 #include "nvim/os/shell.h"
+#include "nvim/os/stdpaths_defs.h"
+#include "nvim/os/time.h"
 #include "nvim/path.h"
 #include "nvim/plines.h"
 #include "nvim/popupmenu.h"
+#include "nvim/pos.h"
 #include "nvim/profile.h"
-#include "nvim/quickfix.h"
 #include "nvim/regexp.h"
 #include "nvim/runtime.h"
-#include "nvim/screen.h"
 #include "nvim/search.h"
 #include "nvim/sha256.h"
-#include "nvim/sign.h"
 #include "nvim/spell.h"
 #include "nvim/spellsuggest.h"
 #include "nvim/state.h"
+#include "nvim/strings.h"
 #include "nvim/syntax.h"
 #include "nvim/tag.h"
-#include "nvim/testing.h"
 #include "nvim/ui.h"
 #include "nvim/undo.h"
 #include "nvim/version.h"
@@ -106,6 +140,7 @@ typedef enum {
 PRAGMA_DIAG_PUSH_IGNORE_MISSING_PROTOTYPES
 PRAGMA_DIAG_PUSH_IGNORE_IMPLICIT_FALLTHROUGH
 # include "funcs.generated.h"
+
 PRAGMA_DIAG_POP
 PRAGMA_DIAG_POP
 #endif
@@ -113,6 +148,8 @@ PRAGMA_DIAG_POP
 static char *e_listblobarg = N_("E899: Argument of %s must be a List or Blob");
 static char *e_invalwindow = N_("E957: Invalid window number");
 static char *e_reduceempty = N_("E998: Reduce of an empty %s with no initial value");
+static char e_using_number_as_bool_nr[]
+  = N_("E1023: Using a Number as a Bool: %d");
 
 /// Dummy va_list for passing to vim_snprintf
 ///
@@ -132,13 +169,13 @@ char *get_function_name(expand_T *xp, int idx)
     intidx = -1;
   }
   if (intidx < 0) {
-    char_u *name = (char_u *)get_user_func_name(xp, idx);
+    char *name = get_user_func_name(xp, idx);
     if (name != NULL) {
       if (*name != NUL && *name != '<'
-          && STRNCMP("g:", xp->xp_pattern, 2) == 0) {
-        return cat_prefix_varname('g', (char *)name);
+          && strncmp("g:", xp->xp_pattern, 2) == 0) {
+        return cat_prefix_varname('g', name);
       }
-      return (char *)name;
+      return name;
     }
   }
 
@@ -155,7 +192,7 @@ char *get_function_name(expand_T *xp, int idx)
   } else {
     IObuff[key_len + 1] = NUL;
   }
-  return (char *)IObuff;
+  return IObuff;
 }
 
 /// Function given to ExpandGeneric() to obtain the list of internal or
@@ -168,9 +205,9 @@ char *get_expr_name(expand_T *xp, int idx)
     intidx = -1;
   }
   if (intidx < 0) {
-    char_u *name = (char_u *)get_function_name(xp, idx);
+    char *name = get_function_name(xp, idx);
     if (name != NULL) {
-      return (char *)name;
+      return name;
     }
   }
   return get_user_var_name(xp, ++intidx);
@@ -189,11 +226,11 @@ const EvalFuncDef *find_internal_func(const char *const name)
   return index >= 0 ? &functions[index] : NULL;
 }
 
-int call_internal_func(const char_u *const fname, const int argcount, typval_T *const argvars,
+int call_internal_func(const char *const fname, const int argcount, typval_T *const argvars,
                        typval_T *const rettv)
   FUNC_ATTR_NONNULL_ALL
 {
-  const EvalFuncDef *const fdef = find_internal_func((const char *)fname);
+  const EvalFuncDef *const fdef = find_internal_func(fname);
   if (fdef == NULL) {
     return FCERR_UNKNOWN;
   } else if (argcount < fdef->min_argc) {
@@ -207,11 +244,11 @@ int call_internal_func(const char_u *const fname, const int argcount, typval_T *
 }
 
 /// Invoke a method for base->method().
-int call_internal_method(const char_u *const fname, const int argcount, typval_T *const argvars,
+int call_internal_method(const char *const fname, const int argcount, typval_T *const argvars,
                          typval_T *const rettv, typval_T *const basetv)
   FUNC_ATTR_NONNULL_ALL
 {
-  const EvalFuncDef *const fdef = find_internal_func((const char *)fname);
+  const EvalFuncDef *const fdef = find_internal_func(fname);
   if (fdef == NULL) {
     return FCERR_UNKNOWN;
   } else if (fdef->base_arg == BASE_NONE) {
@@ -325,20 +362,20 @@ static void f_add(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   rettv->vval.v_number = 1;  // Default: failed.
   if (argvars[0].v_type == VAR_LIST) {
     list_T *const l = argvars[0].vval.v_list;
-    if (!var_check_lock(tv_list_locked(l), N_("add() argument"),
-                        TV_TRANSLATE)) {
+    if (!value_check_lock(tv_list_locked(l), N_("add() argument"),
+                          TV_TRANSLATE)) {
       tv_list_append_tv(l, &argvars[1]);
       tv_copy(&argvars[0], rettv);
     }
   } else if (argvars[0].v_type == VAR_BLOB) {
     blob_T *const b = argvars[0].vval.v_blob;
     if (b != NULL
-        && !var_check_lock(b->bv_lock, N_("add() argument"), TV_TRANSLATE)) {
+        && !value_check_lock(b->bv_lock, N_("add() argument"), TV_TRANSLATE)) {
       bool error = false;
       const varnumber_T n = tv_get_number_chk(&argvars[1], &error);
 
       if (!error) {
-        ga_append(&b->bv_ga, (char)n);
+        ga_append(&b->bv_ga, (uint8_t)n);
         tv_copy(&argvars[0], rettv);
       }
     }
@@ -361,26 +398,6 @@ static void f_api_info(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   (void)object_to_vim(DICTIONARY_OBJ(metadata), rettv, NULL);
 }
 
-/// "append(lnum, string/list)" function
-static void f_append(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  const linenr_T lnum = tv_get_lnum(&argvars[0]);
-
-  set_buffer_lines(curbuf, lnum, true, &argvars[1], rettv);
-}
-
-/// "appendbufline(buf, lnum, string/list)" function
-static void f_appendbufline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  buf_T *const buf = tv_get_buf(&argvars[0], false);
-  if (buf == NULL) {
-    rettv->vval.v_number = 1;  // FAIL
-  } else {
-    const linenr_T lnum = tv_get_lnum_buf(&argvars[1], buf);
-    set_buffer_lines(buf, lnum, true, &argvars[2], rettv);
-  }
-}
-
 /// "atan2()" function
 static void f_atan2(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -408,166 +425,6 @@ static void f_browsedir(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   f_browse(argvars, rettv, fptr);
 }
 
-/// Find a buffer by number or exact name.
-static buf_T *find_buffer(typval_T *avar)
-{
-  buf_T *buf = NULL;
-
-  if (avar->v_type == VAR_NUMBER) {
-    buf = buflist_findnr((int)avar->vval.v_number);
-  } else if (avar->v_type == VAR_STRING && avar->vval.v_string != NULL) {
-    buf = buflist_findname_exp(avar->vval.v_string);
-    if (buf == NULL) {
-      // No full path name match, try a match with a URL or a "nofile"
-      // buffer, these don't use the full path.
-      FOR_ALL_BUFFERS(bp) {
-        if (bp->b_fname != NULL
-            && (path_with_url(bp->b_fname) || bt_nofilename(bp))
-            && strcmp(bp->b_fname, avar->vval.v_string) == 0) {
-          buf = bp;
-          break;
-        }
-      }
-    }
-  }
-  return buf;
-}
-
-/// "bufadd(expr)" function
-static void f_bufadd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  char_u *name = (char_u *)tv_get_string(&argvars[0]);
-
-  rettv->vval.v_number = buflist_add(*name == NUL ? NULL : (char *)name, 0);
-}
-
-/// "bufexists(expr)" function
-static void f_bufexists(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  rettv->vval.v_number = (find_buffer(&argvars[0]) != NULL);
-}
-
-/// "buflisted(expr)" function
-static void f_buflisted(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  buf_T *buf;
-
-  buf = find_buffer(&argvars[0]);
-  rettv->vval.v_number = (buf != NULL && buf->b_p_bl);
-}
-
-/// "bufload(expr)" function
-static void f_bufload(typval_T *argvars, typval_T *unused, EvalFuncData fptr)
-{
-  buf_T *buf = get_buf_arg(&argvars[0]);
-
-  if (buf != NULL && buf->b_ml.ml_mfp == NULL) {
-    aco_save_T aco;
-
-    aucmd_prepbuf(&aco, buf);
-    swap_exists_action = SEA_NONE;
-    open_buffer(false, NULL, 0);
-    aucmd_restbuf(&aco);
-  }
-}
-
-/// "bufloaded(expr)" function
-static void f_bufloaded(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  buf_T *buf;
-
-  buf = find_buffer(&argvars[0]);
-  rettv->vval.v_number = (buf != NULL && buf->b_ml.ml_mfp != NULL);
-}
-
-/// "bufname(expr)" function
-static void f_bufname(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  const buf_T *buf;
-  rettv->v_type = VAR_STRING;
-  rettv->vval.v_string = NULL;
-  if (argvars[0].v_type == VAR_UNKNOWN) {
-    buf = curbuf;
-  } else {
-    buf = tv_get_buf_from_arg(&argvars[0]);
-  }
-  if (buf != NULL && buf->b_fname != NULL) {
-    rettv->vval.v_string = xstrdup(buf->b_fname);
-  }
-}
-
-/// "bufnr(expr)" function
-static void f_bufnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  const buf_T *buf;
-  bool error = false;
-
-  rettv->vval.v_number = -1;
-
-  if (argvars[0].v_type == VAR_UNKNOWN) {
-    buf = curbuf;
-  } else {
-    // Don't use tv_get_buf_from_arg(); we continue if the buffer wasn't found
-    // and the second argument isn't zero, but we want to return early if the
-    // first argument isn't a string or number so only one error is shown.
-    if (!tv_check_str_or_nr(&argvars[0])) {
-      return;
-    }
-    emsg_off++;
-    buf = tv_get_buf(&argvars[0], false);
-    emsg_off--;
-  }
-
-  // If the buffer isn't found and the second argument is not zero create a
-  // new buffer.
-  const char *name;
-  if (buf == NULL
-      && argvars[1].v_type != VAR_UNKNOWN
-      && tv_get_number_chk(&argvars[1], &error) != 0
-      && !error
-      && (name = tv_get_string_chk(&argvars[0])) != NULL) {
-    buf = buflist_new((char *)name, NULL, 1, 0);
-  }
-
-  if (buf != NULL) {
-    rettv->vval.v_number = buf->b_fnum;
-  }
-}
-
-static void buf_win_common(typval_T *argvars, typval_T *rettv, bool get_nr)
-{
-  const buf_T *const buf = tv_get_buf_from_arg(&argvars[0]);
-  if (buf == NULL) {  // no need to search if invalid arg or buffer not found
-    rettv->vval.v_number = -1;
-    return;
-  }
-
-  int winnr = 0;
-  int winid;
-  bool found_buf = false;
-  FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
-    winnr++;
-    if (wp->w_buffer == buf) {
-      found_buf = true;
-      winid = wp->handle;
-      break;
-    }
-  }
-  rettv->vval.v_number = (found_buf ? (get_nr ? winnr : winid) : -1);
-}
-
-/// "bufwinid(nr)" function
-static void f_bufwinid(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  buf_win_common(argvars, rettv, false);
-}
-
-/// "bufwinnr(nr)" function
-static void f_bufwinnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  buf_win_common(argvars, rettv, true);
-}
-
 /// Get buffer by number or pattern.
 buf_T *tv_get_buf(typval_T *tv, int curtab_only)
 {
@@ -578,7 +435,7 @@ buf_T *tv_get_buf(typval_T *tv, int curtab_only)
     return NULL;
   }
 
-  char_u *name = (char_u *)tv->vval.v_string;
+  char *name = tv->vval.v_string;
 
   if (name == NULL || *name == NUL) {
     return curbuf;
@@ -593,7 +450,7 @@ buf_T *tv_get_buf(typval_T *tv, int curtab_only)
   char *save_cpo = p_cpo;
   p_cpo = empty_option;
 
-  buf_T *buf = buflist_findnr(buflist_findpat((char *)name, (char *)name + STRLEN(name),
+  buf_T *buf = buflist_findnr(buflist_findpat(name, name + strlen(name),
                                               true, false, curtab_only));
 
   p_magic = save_magic;
@@ -691,19 +548,19 @@ static void f_call(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   }
 
   bool owned = false;
-  char_u *func;
+  char *func;
   partial_T *partial = NULL;
   if (argvars[0].v_type == VAR_FUNC) {
-    func = (char_u *)argvars[0].vval.v_string;
+    func = argvars[0].vval.v_string;
   } else if (argvars[0].v_type == VAR_PARTIAL) {
     partial = argvars[0].vval.v_partial;
-    func = (char_u *)partial_name(partial);
+    func = partial_name(partial);
   } else if (nlua_is_table_from_lua(&argvars[0])) {
     // TODO(tjdevries): UnifiedCallback
     func = nlua_register_table_as_callable(&argvars[0]);
     owned = true;
   } else {
-    func = (char_u *)tv_get_string(&argvars[0]);
+    func = (char *)tv_get_string(&argvars[0]);
   }
 
   if (*func == NUL) {
@@ -791,6 +648,14 @@ static void f_chansend(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
   ptrdiff_t input_len = 0;
   char *input = NULL;
+  uint64_t id = (uint64_t)argvars[0].vval.v_number;
+#ifdef UNIX
+  bool crlf = false;
+#else
+  Channel *chan = find_channel(id);
+  bool crlf = (chan != NULL && chan->term) ? true: false;
+#endif
+
   if (argvars[1].v_type == VAR_BLOB) {
     const blob_T *const b = argvars[1].vval.v_blob;
     input_len = tv_blob_len(b);
@@ -798,7 +663,7 @@ static void f_chansend(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       input = xmemdup(b->bv_ga.ga_data, (size_t)input_len);
     }
   } else {
-    input = save_tv_as_string(&argvars[1], &input_len, false);
+    input = save_tv_as_string(&argvars[1], &input_len, false, crlf);
   }
 
   if (!input) {
@@ -806,7 +671,6 @@ static void f_chansend(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     // or there is no input to send.
     return;
   }
-  uint64_t id = (uint64_t)argvars[0].vval.v_number;
   const char *error = NULL;
   rettv->vval.v_number = (varnumber_T)channel_send(id, input, (size_t)input_len, true, &error);
   if (error) {
@@ -832,9 +696,32 @@ static void f_char2nr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 ///          otherwise the byte index of the column.
 static void get_col(typval_T *argvars, typval_T *rettv, bool charcol)
 {
+  if (tv_check_for_string_or_list_arg(argvars, 0) == FAIL
+      || tv_check_for_opt_number_arg(argvars, 1) == FAIL) {
+    return;
+  }
+
+  switchwin_T switchwin;
+  bool winchanged = false;
+
+  if (argvars[1].v_type != VAR_UNKNOWN) {
+    // use the window specified in the second argument
+    tabpage_T *tp;
+    win_T *wp = win_id2wp_tp((int)tv_get_number(&argvars[1]), &tp);
+    if (wp == NULL || tp == NULL) {
+      return;
+    }
+
+    if (switch_win_noblock(&switchwin, wp, tp, true) != OK) {
+      return;
+    }
+
+    check_cursor();
+    winchanged = true;
+  }
+
   colnr_T col = 0;
   int fnum = curbuf->b_fnum;
-
   pos_T *fp = var2fpos(&argvars[0], false, &fnum, charcol);
   if (fp != NULL && fnum == curbuf->b_fnum) {
     if (fp->col == MAXCOL) {
@@ -862,6 +749,10 @@ static void get_col(typval_T *argvars, typval_T *rettv, bool charcol)
     }
   }
   rettv->vval.v_number = col;
+
+  if (winchanged) {
+    restore_win_noblock(&switchwin, true);
+  }
 }
 
 /// "charcol()" function
@@ -894,7 +785,7 @@ static void f_charidx(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     countcc = (int)tv_get_number(&argvars[2]);
   }
   if (countcc < 0 || countcc > 1) {
-    emsg(_(e_invarg));
+    semsg(_(e_using_number_as_bool_nr), countcc);
     return;
   }
 
@@ -931,7 +822,7 @@ static void f_chdir(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
   // Return the current directory
   char *cwd = xmalloc(MAXPATHL);
-  if (os_dirname((char_u *)cwd, MAXPATHL) != FAIL) {
+  if (os_dirname(cwd, MAXPATHL) != FAIL) {
 #ifdef BACKSLASH_IN_FILENAME
     slash_adjust(cwd);
 #endif
@@ -968,14 +859,14 @@ static void f_cindent(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
 win_T *get_optional_window(typval_T *argvars, int idx)
 {
-  win_T *win = curwin;
+  if (argvars[idx].v_type == VAR_UNKNOWN) {
+    return curwin;
+  }
 
-  if (argvars[idx].v_type != VAR_UNKNOWN) {
-    win = find_win_by_nr_or_id(&argvars[idx]);
-    if (win == NULL) {
-      emsg(_(e_invalwindow));
-      return NULL;
-    }
+  win_T *win = find_win_by_nr_or_id(&argvars[idx]);
+  if (win == NULL) {
+    emsg(_(e_invalwindow));
+    return NULL;
   }
   return win;
 }
@@ -1057,12 +948,12 @@ static void f_count(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   }
 
   if (argvars[0].v_type == VAR_STRING) {
-    const char_u *expr = (char_u *)tv_get_string_chk(&argvars[1]);
-    const char_u *p = (char_u *)argvars[0].vval.v_string;
+    const char *expr = tv_get_string_chk(&argvars[1]);
+    const char *p = argvars[0].vval.v_string;
 
     if (!error && expr != NULL && *expr != NUL && p != NULL) {
       if (ic) {
-        const size_t len = STRLEN(expr);
+        const size_t len = strlen(expr);
 
         while (*p != NUL) {
           if (mb_strnicmp((char *)p, (char *)expr, len) == 0) {
@@ -1073,10 +964,10 @@ static void f_count(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
           }
         }
       } else {
-        char_u *next;
-        while ((next = (char_u *)strstr((char *)p, (char *)expr)) != NULL) {
+        char *next;
+        while ((next = strstr((char *)p, (char *)expr)) != NULL) {
           n++;
-          p = next + STRLEN(expr);
+          p = next + strlen(expr);
         }
       }
     }
@@ -1132,29 +1023,6 @@ static void f_count(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   rettv->vval.v_number = n;
 }
 
-/// "cscope_connection([{num} , {dbpath} [, {prepend}]])" function
-///
-/// Checks the existence of a cscope connection.
-static void f_cscope_connection(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  int num = 0;
-  const char *dbpath = NULL;
-  const char *prepend = NULL;
-  char buf[NUMBUFLEN];
-
-  if (argvars[0].v_type != VAR_UNKNOWN
-      && argvars[1].v_type != VAR_UNKNOWN) {
-    num = (int)tv_get_number(&argvars[0]);
-    dbpath = tv_get_string(&argvars[1]);
-    if (argvars[2].v_type != VAR_UNKNOWN) {
-      prepend = tv_get_string_buf(&argvars[2], buf);
-    }
-  }
-
-  rettv->vval.v_number = cs_connection(num, (char_u *)dbpath,
-                                       (char_u *)prepend);
-}
-
 /// "ctxget([{index}])" function
 static void f_ctxget(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -1348,19 +1216,21 @@ static void f_debugbreak(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   int pid = (int)tv_get_number(&argvars[0]);
   if (pid == 0) {
     emsg(_(e_invarg));
-  } else {
+    return;
+  }
+
 #ifdef MSWIN
-    HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS, 0, pid);
+  HANDLE hProcess = OpenProcess(PROCESS_ALL_ACCESS, 0, pid);
+  if (hProcess == NULL) {
+    return;
+  }
 
-    if (hProcess != NULL) {
-      DebugBreakProcess(hProcess);
-      CloseHandle(hProcess);
-      rettv->vval.v_number = OK;
-    }
+  DebugBreakProcess(hProcess);
+  CloseHandle(hProcess);
+  rettv->vval.v_number = OK;
 #else
-    uv_kill(pid, SIGINT);
+  uv_kill(pid, SIGINT);
 #endif
-  }
 }
 
 /// "deepcopy()" function
@@ -1369,10 +1239,10 @@ static void f_deepcopy(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   int noref = 0;
 
   if (argvars[1].v_type != VAR_UNKNOWN) {
-    noref = (int)tv_get_number_chk(&argvars[1], NULL);
+    noref = (int)tv_get_bool_chk(&argvars[1], NULL);
   }
   if (noref < 0 || noref > 1) {
-    emsg(_(e_invarg));
+    semsg(_(e_using_number_as_bool_nr), noref);
   } else {
     var_item_copy(NULL, &argvars[0], rettv, true, (noref == 0
                                                    ? get_copyID()
@@ -1489,82 +1359,6 @@ static void f_dictwatcherdel(typval_T *argvars, typval_T *rettv, EvalFuncData fp
   callback_free(&callback);
 }
 
-/// "deletebufline()" function
-static void f_deletebufline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  buf_T *const buf = tv_get_buf(&argvars[0], false);
-  if (buf == NULL) {
-    rettv->vval.v_number = 1;  // FAIL
-    return;
-  }
-  const bool is_curbuf = buf == curbuf;
-  const bool save_VIsual_active = VIsual_active;
-
-  linenr_T last;
-  const linenr_T first = tv_get_lnum_buf(&argvars[1], buf);
-  if (argvars[2].v_type != VAR_UNKNOWN) {
-    last = tv_get_lnum_buf(&argvars[2], buf);
-  } else {
-    last = first;
-  }
-
-  if (buf->b_ml.ml_mfp == NULL || first < 1
-      || first > buf->b_ml.ml_line_count || last < first) {
-    rettv->vval.v_number = 1;  // FAIL
-    return;
-  }
-
-  buf_T *curbuf_save = NULL;
-  win_T *curwin_save = NULL;
-  if (!is_curbuf) {
-    VIsual_active = false;
-    curbuf_save = curbuf;
-    curwin_save = curwin;
-    curbuf = buf;
-    find_win_for_curbuf();
-  }
-  if (last > curbuf->b_ml.ml_line_count) {
-    last = curbuf->b_ml.ml_line_count;
-  }
-  const long count = last - first + 1;
-
-  // When coming here from Insert mode, sync undo, so that this can be
-  // undone separately from what was previously inserted.
-  if (u_sync_once == 2) {
-    u_sync_once = 1;  // notify that u_sync() was called
-    u_sync(true);
-  }
-
-  if (u_save(first - 1, last + 1) == FAIL) {
-    rettv->vval.v_number = 1;  // FAIL
-  } else {
-    for (linenr_T lnum = first; lnum <= last; lnum++) {
-      ml_delete(first, true);
-    }
-
-    FOR_ALL_TAB_WINDOWS(tp, wp) {
-      if (wp->w_buffer == buf) {
-        if (wp->w_cursor.lnum > last) {
-          wp->w_cursor.lnum -= (linenr_T)count;
-        } else if (wp->w_cursor.lnum > first) {
-          wp->w_cursor.lnum = first;
-        }
-        if (wp->w_cursor.lnum > wp->w_buffer->b_ml.ml_line_count) {
-          wp->w_cursor.lnum = wp->w_buffer->b_ml.ml_line_count;
-        }
-      }
-    }
-    check_cursor_col();
-    deleted_lines_mark(first, count);
-  }
-
-  if (!is_curbuf) {
-    curbuf = curbuf_save;
-    curwin = curwin_save;
-    VIsual_active = save_VIsual_active;
-  }
-}
-
 /// "did_filetype()" function
 static void f_did_filetype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -1595,9 +1389,10 @@ static void f_diff_hlID(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       || changedtick != buf_get_changedtick(curbuf)
       || fnum != curbuf->b_fnum) {
     // New line, buffer, change: need to get the values.
-    int filler_lines = diff_check(curwin, lnum);
-    if (filler_lines < 0) {
-      if (filler_lines == -1) {
+    int linestatus = 0;
+    int filler_lines = diff_check_with_linestatus(curwin, lnum, &linestatus);
+    if (filler_lines < 0 || linestatus < 0) {
+      if (filler_lines == -1 || linestatus == -1) {
         change_start = MAXCOL;
         change_end = -1;
         if (diff_find_change(curwin, lnum, &change_start, &change_end)) {
@@ -1624,7 +1419,7 @@ static void f_diff_hlID(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       hlID = HLF_CHD;  // Changed line.
     }
   }
-  rettv->vval.v_number = hlID == (hlf_T)0 ? 0 : (int)(hlID + 1);
+  rettv->vval.v_number = hlID == (hlf_T)0 ? 0 : (hlID + 1);
 }
 
 /// "empty({expr})" function
@@ -1727,23 +1522,22 @@ static void f_escape(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
   char buf[NUMBUFLEN];
 
-  rettv->vval.v_string = (char *)vim_strsave_escaped((const char_u *)tv_get_string(&argvars[0]),
-                                                     (const char_u *)tv_get_string_buf(&argvars[1],
-                                                                                       buf));
+  rettv->vval.v_string = vim_strsave_escaped(tv_get_string(&argvars[0]),
+                                             tv_get_string_buf(&argvars[1], buf));
   rettv->v_type = VAR_STRING;
 }
 
 /// "getenv()" function
 static void f_getenv(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
-  char_u *p = (char_u *)vim_getenv(tv_get_string(&argvars[0]));
+  char *p = vim_getenv(tv_get_string(&argvars[0]));
 
   if (p == NULL) {
     rettv->v_type = VAR_SPECIAL;
     rettv->vval.v_special = kSpecialVarNull;
     return;
   }
-  rettv->vval.v_string = (char *)p;
+  rettv->vval.v_string = p;
   rettv->v_type = VAR_STRING;
 }
 
@@ -1804,7 +1598,7 @@ static char *get_list_line(int c, void *cookie, int indent, bool do_concat)
   return s == NULL ? NULL : xstrdup(s);
 }
 
-static void execute_common(typval_T *argvars, typval_T *rettv, int arg_off)
+void execute_common(typval_T *argvars, typval_T *rettv, int arg_off)
 {
   const int save_msg_silent = msg_silent;
   const int save_emsg_silent = emsg_silent;
@@ -1888,21 +1682,6 @@ static void f_execute(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   execute_common(argvars, rettv, 0);
 }
 
-/// "win_execute(win_id, command)" function
-static void f_win_execute(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  // Return an empty string if something fails.
-  rettv->v_type = VAR_STRING;
-  rettv->vval.v_string = NULL;
-
-  int id = (int)tv_get_number(argvars);
-  tabpage_T *tp;
-  win_T *wp = win_id2wp_tp(id, &tp);
-  if (wp != NULL && tp != NULL) {
-    WIN_EXECUTE(wp, tp, execute_common(argvars, rettv, 1));
-  }
-}
-
 /// "exepath()" function
 static void f_exepath(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -1916,7 +1695,7 @@ static void f_exepath(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
 #ifdef BACKSLASH_IN_FILENAME
   if (path != NULL) {
-    slash_adjust((char_u *)path);
+    slash_adjust(path);
   }
 #endif
 
@@ -1943,14 +1722,9 @@ static void f_exists(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       xfree(exp);
     }
   } else if (*p == '&' || *p == '+') {  // Option.
-    bool working = (*p == '+');  // whether option needs to be working
-    int opt_flags;
-
-    if (find_option_end(&p, &opt_flags) != NULL) {
-      int opt_idx = findoption(p);
-      n = (opt_idx >= 0 && (!working || get_varp_scope(get_option(opt_idx), opt_flags) != NULL));
-    } else {
-      n = false;
+    n = (get_option_tv(&p, NULL, true) == OK);
+    if (*skipwhite(p) != NUL) {
+      n = false;  // Trailing garbage.
     }
   } else if (*p == '*') {  // Internal or user defined function.
     n = function_exists(p + 1, false);
@@ -1975,7 +1749,7 @@ static void f_expand(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   int options = WILD_SILENT|WILD_USE_NL|WILD_LIST_NOTFOUND;
   bool error = false;
 #ifdef BACKSLASH_IN_FILENAME
-  char_u *p_csl_save = p_csl;
+  char *p_csl_save = p_csl;
 
   // avoid using 'completeslash' here
   p_csl = empty_option;
@@ -1996,7 +1770,7 @@ static void f_expand(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     }
     size_t len;
     char *errormsg = NULL;
-    char_u *result = eval_vars((char_u *)s, (char_u *)s, &len, NULL, &errormsg, NULL, false);
+    char *result = eval_vars((char *)s, s, &len, NULL, &errormsg, NULL, false);
     if (p_verbose == 0) {
       emsg_off--;
     } else if (errormsg != NULL) {
@@ -2009,7 +1783,7 @@ static void f_expand(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       }
       XFREE_CLEAR(result);
     } else {
-      rettv->vval.v_string = (char *)result;
+      rettv->vval.v_string = result;
     }
   } else {
     // When the optional second argument is non-zero, don't remove matches
@@ -2062,6 +1836,12 @@ static void f_menu_get(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 static void f_expandcmd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
   char *errormsg = NULL;
+  bool emsgoff = true;
+
+  if (argvars[1].v_type == VAR_DICT
+      && tv_dict_get_bool(argvars[1].vval.v_dict, "errmsg", kBoolVarFalse)) {
+    emsgoff = false;
+  }
 
   rettv->v_type = VAR_STRING;
   char *cmdstr = xstrdup(tv_get_string(&argvars[0]));
@@ -2075,9 +1855,17 @@ static void f_expandcmd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   };
   eap.argt |= EX_NOSPC;
 
-  emsg_off++;
-  expand_filename(&eap, &cmdstr, &errormsg);
-  emsg_off--;
+  if (emsgoff) {
+    emsg_off++;
+  }
+  if (expand_filename(&eap, &cmdstr, &errormsg) == FAIL) {
+    if (!emsgoff && errormsg != NULL && *errormsg != NUL) {
+      emsg(errormsg);
+    }
+  }
+  if (emsgoff) {
+    emsg_off--;
+  }
 
   rettv->vval.v_string = cmdstr;
 }
@@ -2108,9 +1896,9 @@ static void f_flatten(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
   list_T *list = argvars[0].vval.v_list;
   if (list != NULL
-      && !var_check_lock(tv_list_locked(list),
-                         N_("flatten() argument"),
-                         TV_TRANSLATE)
+      && !value_check_lock(tv_list_locked(list),
+                           N_("flatten() argument"),
+                           TV_TRANSLATE)
       && tv_list_flatten(list, maxdepth) == OK) {
     tv_copy(&argvars[0], rettv);
   }
@@ -2127,7 +1915,7 @@ static void f_extend(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
     list_T *const l1 = argvars[0].vval.v_list;
     list_T *const l2 = argvars[1].vval.v_list;
-    if (!var_check_lock(tv_list_locked(l1), arg_errmsg, TV_TRANSLATE)) {
+    if (!value_check_lock(tv_list_locked(l1), arg_errmsg, TV_TRANSLATE)) {
       listitem_T *item;
       if (argvars[2].v_type != VAR_UNKNOWN) {
         long before = (long)tv_get_number_chk(&argvars[2], &error);
@@ -2156,13 +1944,13 @@ static void f_extend(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     dict_T *const d1 = argvars[0].vval.v_dict;
     dict_T *const d2 = argvars[1].vval.v_dict;
     if (d1 == NULL) {
-      const bool locked = var_check_lock(VAR_FIXED, arg_errmsg, TV_TRANSLATE);
+      const bool locked = value_check_lock(VAR_FIXED, arg_errmsg, TV_TRANSLATE);
       (void)locked;
       assert(locked == true);
     } else if (d2 == NULL) {
       // Do nothing
       tv_copy(&argvars[0], rettv);
-    } else if (!var_check_lock(d1->dv_lock, arg_errmsg, TV_TRANSLATE)) {
+    } else if (!value_check_lock(d1->dv_lock, arg_errmsg, TV_TRANSLATE)) {
       const char *action = "force";
       // Check the third argument.
       if (argvars[2].v_type != VAR_UNKNOWN) {
@@ -2233,8 +2021,8 @@ static void f_filewritable(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
 
 static void findfilendir(typval_T *argvars, typval_T *rettv, int find_what)
 {
-  char_u *fresult = NULL;
-  char_u *path = *curbuf->b_p_path == NUL ? p_path : (char_u *)curbuf->b_p_path;
+  char *fresult = NULL;
+  char *path = *curbuf->b_p_path == NUL ? p_path : curbuf->b_p_path;
   int count = 1;
   bool first = true;
   bool error = false;
@@ -2251,7 +2039,7 @@ static void findfilendir(typval_T *argvars, typval_T *rettv, int find_what)
       error = true;
     } else {
       if (*p != NUL) {
-        path = (char_u *)p;
+        path = (char *)p;
       }
 
       if (argvars[2].v_type != VAR_UNKNOWN) {
@@ -2269,13 +2057,13 @@ static void findfilendir(typval_T *argvars, typval_T *rettv, int find_what)
       if (rettv->v_type == VAR_STRING || rettv->v_type == VAR_LIST) {
         xfree(fresult);
       }
-      fresult = find_file_in_path_option(first ? (char_u *)fname : NULL,
+      fresult = find_file_in_path_option(first ? (char *)fname : NULL,
                                          first ? strlen(fname) : 0,
                                          0, first, path,
-                                         find_what, (char_u *)curbuf->b_ffname,
+                                         find_what, curbuf->b_ffname,
                                          (find_what == FINDFILE_DIR
-                                          ? (char_u *)""
-                                          : (char_u *)curbuf->b_p_sua));
+                                          ? ""
+                                          : curbuf->b_p_sua));
       first = false;
 
       if (fresult != NULL && rettv->v_type == VAR_LIST) {
@@ -2285,7 +2073,7 @@ static void findfilendir(typval_T *argvars, typval_T *rettv, int find_what)
   }
 
   if (rettv->v_type == VAR_STRING) {
-    rettv->vval.v_string = (char *)fresult;
+    rettv->vval.v_string = fresult;
   }
 }
 
@@ -2312,14 +2100,16 @@ static void f_float2nr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
   float_T f;
 
-  if (tv_get_float_chk(argvars, &f)) {
-    if (f <= (float_T) - VARNUMBER_MAX + DBL_EPSILON) {
-      rettv->vval.v_number = -VARNUMBER_MAX;
-    } else if (f >= (float_T)VARNUMBER_MAX - DBL_EPSILON) {
-      rettv->vval.v_number = VARNUMBER_MAX;
-    } else {
-      rettv->vval.v_number = (varnumber_T)f;
-    }
+  if (!tv_get_float_chk(argvars, &f)) {
+    return;
+  }
+
+  if (f <= (float_T) - VARNUMBER_MAX + DBL_EPSILON) {
+    rettv->vval.v_number = -VARNUMBER_MAX;
+  } else if (f >= (float_T)VARNUMBER_MAX - DBL_EPSILON) {
+    rettv->vval.v_number = VARNUMBER_MAX;
+  } else {
+    rettv->vval.v_number = (varnumber_T)f;
   }
 }
 
@@ -2347,7 +2137,7 @@ static void f_fnameescape(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 /// "fnamemodify({fname}, {mods})" function
 static void f_fnamemodify(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
-  char_u *fbuf = NULL;
+  char *fbuf = NULL;
   size_t len = 0;
   char buf[NUMBUFLEN];
   const char *fname = tv_get_string_chk(&argvars[0]);
@@ -2359,7 +2149,7 @@ static void f_fnamemodify(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     if (*mods != NUL) {
       size_t usedlen = 0;
       (void)modify_fname((char *)mods, false, &usedlen,
-                         (char **)&fname, (char **)&fbuf, &len);
+                         (char **)&fname, &fbuf, &len);
     }
   }
 
@@ -2454,13 +2244,17 @@ static void f_get(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       const char *const what = tv_get_string(&argvars[1]);
 
       if (strcmp(what, "func") == 0 || strcmp(what, "name") == 0) {
+        const char *name = partial_name(pt);
         rettv->v_type = (*what == 'f' ? VAR_FUNC : VAR_STRING);
-        const char *const n = (const char *)partial_name(pt);
-        assert(n != NULL);
-        rettv->vval.v_string = xstrdup(n);
+        assert(name != NULL);
         if (rettv->v_type == VAR_FUNC) {
-          func_ref((char_u *)rettv->vval.v_string);
+          func_ref((char *)name);
         }
+        if (*what == 'n' && pt->pt_name == NULL && pt->pt_func != NULL) {
+          // use <SNR> instead of the byte code
+          name = printable_func_name(pt->pt_func);
+        }
+        rettv->vval.v_string = xstrdup(name);
       } else if (strcmp(what, "dict") == 0) {
         what_is_dict = true;
         if (pt->pt_dict != NULL) {
@@ -2495,117 +2289,6 @@ static void f_get(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   }
 }
 
-/// "getbufinfo()" function
-static void f_getbufinfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  buf_T *argbuf = NULL;
-  bool filtered = false;
-  bool sel_buflisted = false;
-  bool sel_bufloaded = false;
-  bool sel_bufmodified = false;
-
-  tv_list_alloc_ret(rettv, kListLenMayKnow);
-
-  // List of all the buffers or selected buffers
-  if (argvars[0].v_type == VAR_DICT) {
-    dict_T *sel_d = argvars[0].vval.v_dict;
-
-    if (sel_d != NULL) {
-      dictitem_T *di;
-
-      filtered = true;
-
-      di = tv_dict_find(sel_d, S_LEN("buflisted"));
-      if (di != NULL && tv_get_number(&di->di_tv)) {
-        sel_buflisted = true;
-      }
-
-      di = tv_dict_find(sel_d, S_LEN("bufloaded"));
-      if (di != NULL && tv_get_number(&di->di_tv)) {
-        sel_bufloaded = true;
-      }
-      di = tv_dict_find(sel_d, S_LEN("bufmodified"));
-      if (di != NULL && tv_get_number(&di->di_tv)) {
-        sel_bufmodified = true;
-      }
-    }
-  } else if (argvars[0].v_type != VAR_UNKNOWN) {
-    // Information about one buffer.  Argument specifies the buffer
-    argbuf = tv_get_buf_from_arg(&argvars[0]);
-    if (argbuf == NULL) {
-      return;
-    }
-  }
-
-  // Return information about all the buffers or a specified buffer
-  FOR_ALL_BUFFERS(buf) {
-    if (argbuf != NULL && argbuf != buf) {
-      continue;
-    }
-    if (filtered && ((sel_bufloaded && buf->b_ml.ml_mfp == NULL)
-                     || (sel_buflisted && !buf->b_p_bl)
-                     || (sel_bufmodified && !buf->b_changed))) {
-      continue;
-    }
-
-    dict_T *const d = get_buffer_info(buf);
-    tv_list_append_dict(rettv->vval.v_list, d);
-    if (argbuf != NULL) {
-      return;
-    }
-  }
-}
-
-/// Get line or list of lines from buffer "buf" into "rettv".
-///
-/// @param retlist  if true, then the lines are returned as a Vim List.
-///
-/// @return  range (from start to end) of lines in rettv from the specified
-///          buffer.
-static void get_buffer_lines(buf_T *buf, linenr_T start, linenr_T end, int retlist, typval_T *rettv)
-{
-  rettv->v_type = (retlist ? VAR_LIST : VAR_STRING);
-  rettv->vval.v_string = NULL;
-
-  if (buf == NULL || buf->b_ml.ml_mfp == NULL || start < 0 || end < start) {
-    if (retlist) {
-      tv_list_alloc_ret(rettv, 0);
-    }
-    return;
-  }
-
-  if (retlist) {
-    if (start < 1) {
-      start = 1;
-    }
-    if (end > buf->b_ml.ml_line_count) {
-      end = buf->b_ml.ml_line_count;
-    }
-    tv_list_alloc_ret(rettv, end - start + 1);
-    while (start <= end) {
-      tv_list_append_string(rettv->vval.v_list,
-                            (const char *)ml_get_buf(buf, start++, false), -1);
-    }
-  } else {
-    rettv->v_type = VAR_STRING;
-    rettv->vval.v_string = ((start >= 1 && start <= buf->b_ml.ml_line_count)
-                            ? xstrdup(ml_get_buf(buf, start, false)) : NULL);
-  }
-}
-
-/// "getbufline()" function
-static void f_getbufline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  buf_T *const buf = tv_get_buf_from_arg(&argvars[0]);
-
-  const linenr_T lnum = tv_get_lnum_buf(&argvars[1], buf);
-  const linenr_T end = (argvars[2].v_type == VAR_UNKNOWN
-                        ? lnum
-                        : tv_get_lnum_buf(&argvars[2], buf));
-
-  get_buffer_lines(buf, lnum, end, true, rettv);
-}
-
 /// "getchangelist()" function
 static void f_getchangelist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -2729,15 +2412,6 @@ static void f_getcharsearch(typval_T *argvars, typval_T *rettv, EvalFuncData fpt
   tv_dict_add_nr(dict, S_LEN("until"), last_csearch_until());
 }
 
-/// "getcmdwintype()" function
-static void f_getcmdwintype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  rettv->v_type = VAR_STRING;
-  rettv->vval.v_string = NULL;
-  rettv->vval.v_string = xmallocz(1);
-  rettv->vval.v_string[0] = (char)cmdwin_type;
-}
-
 /// `getcwd([{win}[, {tab}]])` function
 ///
 /// Every scope not specified implies the currently selected scope object.
@@ -2842,13 +2516,13 @@ static void f_getcwd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     }
     FALLTHROUGH;            // In global directory, just need to get OS CWD.
   case kCdScopeInvalid:     // If called without any arguments, get OS CWD.
-    if (os_dirname((char_u *)cwd, MAXPATHL) == FAIL) {
+    if (os_dirname(cwd, MAXPATHL) == FAIL) {
       from = "";  // Return empty string on failure.
     }
   }
 
   if (from) {
-    STRLCPY(cwd, from, MAXPATHL);
+    xstrlcpy(cwd, from, MAXPATHL);
   }
 
   rettv->vval.v_string = xstrdup(cwd);
@@ -2870,7 +2544,7 @@ static void f_getfontname(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 static void f_getfperm(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
   char *perm = NULL;
-  char_u flags[] = "rwx";
+  char flags[] = "rwx";
 
   const char *filename = tv_get_string(&argvars[0]);
   int32_t file_perm = os_getperm(filename);
@@ -2878,7 +2552,7 @@ static void f_getfperm(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     perm = xstrdup("---------");
     for (int i = 0; i < 9; i++) {
       if (file_perm & (1 << (8 - i))) {
-        perm[i] = (char)flags[i % 3];
+        perm[i] = flags[i % 3];
       }
     }
   }
@@ -2989,24 +2663,6 @@ static void f_getjumplist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   }
 }
 
-/// "getline(lnum, [end])" function
-static void f_getline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  linenr_T end;
-  bool retlist;
-
-  const linenr_T lnum = tv_get_lnum(argvars);
-  if (argvars[1].v_type == VAR_UNKNOWN) {
-    end = lnum;
-    retlist = false;
-  } else {
-    end = tv_get_lnum(&argvars[1]);
-    retlist = true;
-  }
-
-  get_buffer_lines(curbuf, lnum, end, retlist, rettv);
-}
-
 /// "getmarklist()" function
 static void f_getmarklist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -3094,19 +2750,19 @@ static void f_getpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 /// Returns zero on error.
 static int getreg_get_regname(typval_T *argvars)
 {
-  const char_u *strregname;
+  const char *strregname;
 
   if (argvars[0].v_type != VAR_UNKNOWN) {
-    strregname = (const char_u *)tv_get_string_chk(&argvars[0]);
+    strregname = tv_get_string_chk(&argvars[0]);
     if (strregname == NULL) {  // type error; errmsg already given
       return 0;
     }
   } else {
     // Default to v:register
-    strregname = (char_u *)get_vim_var_str(VV_REG);
+    strregname = get_vim_var_str(VV_REG);
   }
 
-  return *strregname == 0 ? '"' : *strregname;
+  return *strregname == 0 ? '"' : (uint8_t)(*strregname);
 }
 
 /// "getreg()" function
@@ -3165,38 +2821,6 @@ static void f_getregtype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   rettv->vval.v_string = xstrdup(buf);
 }
 
-/// "gettabinfo()" function
-static void f_gettabinfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  tabpage_T *tparg = NULL;
-
-  tv_list_alloc_ret(rettv, (argvars[0].v_type == VAR_UNKNOWN
-                            ? 1
-                            : kListLenMayKnow));
-
-  if (argvars[0].v_type != VAR_UNKNOWN) {
-    // Information about one tab page
-    tparg = find_tabpage((int)tv_get_number_chk(&argvars[0], NULL));
-    if (tparg == NULL) {
-      return;
-    }
-  }
-
-  // Get information about a specific tab page or all tab pages
-  int tpnr = 0;
-  FOR_ALL_TABS(tp) {
-    tpnr++;
-    if (tparg != NULL && tp != tparg) {
-      continue;
-    }
-    dict_T *const d = get_tabpage_info(tp, tpnr);
-    tv_list_append_dict(rettv->vval.v_list, d);
-    if (tparg != NULL) {
-      return;
-    }
-  }
-}
-
 /// "gettagstack()" function
 static void f_gettagstack(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -3214,41 +2838,6 @@ static void f_gettagstack(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   get_tagstack(wp, rettv->vval.v_dict);
 }
 
-/// "getwininfo()" function
-static void f_getwininfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  win_T *wparg = NULL;
-
-  tv_list_alloc_ret(rettv, kListLenMayKnow);
-
-  if (argvars[0].v_type != VAR_UNKNOWN) {
-    wparg = win_id2wp((int)tv_get_number(&argvars[0]));
-    if (wparg == NULL) {
-      return;
-    }
-  }
-
-  // Collect information about either all the windows across all the tab
-  // pages or one particular window.
-  int16_t tabnr = 0;
-  FOR_ALL_TABS(tp) {
-    tabnr++;
-    int16_t winnr = 0;
-    FOR_ALL_WINDOWS_IN_TAB(wp, tp) {
-      winnr++;
-      if (wparg != NULL && wp != wparg) {
-        continue;
-      }
-      dict_T *const d = get_win_info(wp, tabnr, winnr);
-      tv_list_append_dict(rettv->vval.v_list, d);
-      if (wparg != NULL) {
-        // found information about a specific window
-        return;
-      }
-    }
-  }
-}
-
 /// Dummy timer callback. Used by f_wait().
 static void dummy_timer_due_cb(TimeWatcher *tw, void *data)
 {}
@@ -3313,111 +2902,6 @@ static void f_wait(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   time_watcher_close(tw, dummy_timer_close_cb);
 }
 
-/// "win_screenpos()" function
-static void f_win_screenpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  tv_list_alloc_ret(rettv, 2);
-  const win_T *const wp = find_win_by_nr_or_id(&argvars[0]);
-  tv_list_append_number(rettv->vval.v_list, wp == NULL ? 0 : wp->w_winrow + 1);
-  tv_list_append_number(rettv->vval.v_list, wp == NULL ? 0 : wp->w_wincol + 1);
-}
-
-/// Move the window wp into a new split of targetwin in a given direction
-static void win_move_into_split(win_T *wp, win_T *targetwin, int size, int flags)
-{
-  int height = wp->w_height;
-  win_T *oldwin = curwin;
-
-  if (wp == targetwin || wp == aucmd_win) {
-    return;
-  }
-
-  // Jump to the target window
-  if (curwin != targetwin) {
-    win_goto(targetwin);
-  }
-
-  // Remove the old window and frame from the tree of frames
-  int dir;
-  (void)winframe_remove(wp, &dir, NULL);
-  win_remove(wp, NULL);
-  last_status(false);     // may need to remove last status line
-  (void)win_comp_pos();   // recompute window positions
-
-  // Split a window on the desired side and put the old window there
-  (void)win_split_ins(size, flags, wp, dir);
-
-  // If splitting horizontally, try to preserve height
-  if (size == 0 && !(flags & WSP_VERT)) {
-    win_setheight_win(height, wp);
-    if (p_ea) {
-      win_equal(wp, true, 'v');
-    }
-  }
-
-  if (oldwin != curwin) {
-    win_goto(oldwin);
-  }
-}
-
-/// "win_splitmove()" function
-static void f_win_splitmove(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
-  win_T *targetwin = find_win_by_nr_or_id(&argvars[1]);
-
-  if (wp == NULL || targetwin == NULL || wp == targetwin
-      || !win_valid(wp) || !win_valid(targetwin)
-      || win_valid_floating(wp) || win_valid_floating(targetwin)) {
-    emsg(_(e_invalwindow));
-    rettv->vval.v_number = -1;
-    return;
-  }
-
-  int flags = 0, size = 0;
-
-  if (argvars[2].v_type != VAR_UNKNOWN) {
-    dict_T *d;
-    dictitem_T *di;
-
-    if (argvars[2].v_type != VAR_DICT || argvars[2].vval.v_dict == NULL) {
-      emsg(_(e_invarg));
-      return;
-    }
-
-    d = argvars[2].vval.v_dict;
-    if (tv_dict_get_number(d, "vertical")) {
-      flags |= WSP_VERT;
-    }
-    if ((di = tv_dict_find(d, "rightbelow", -1)) != NULL) {
-      flags |= tv_get_number(&di->di_tv) ? WSP_BELOW : WSP_ABOVE;
-    }
-    size = (int)tv_dict_get_number(d, "size");
-  }
-
-  win_move_into_split(wp, targetwin, size, flags);
-}
-
-/// "getwinpos({timeout})" function
-static void f_getwinpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  tv_list_alloc_ret(rettv, 2);
-  tv_list_append_number(rettv->vval.v_list, -1);
-  tv_list_append_number(rettv->vval.v_list, -1);
-}
-
-/// "getwinposx()" function
-static void f_getwinposx(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  rettv->vval.v_number = -1;
-}
-
-/// "getwinposy()" function
-static void f_getwinposy(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  rettv->vval.v_number = -1;
-}
-
 /// "glob()" function
 static void f_glob(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -3498,7 +2982,7 @@ static void f_globpath(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   const char *const file = tv_get_string_buf_chk(&argvars[1], buf1);
   if (file != NULL && !error) {
     garray_T ga;
-    ga_init(&ga, (int)sizeof(char_u *), 10);
+    ga_init(&ga, (int)sizeof(char *), 10);
     globpath((char *)tv_get_string(&argvars[0]), (char *)file, &ga, flags);
 
     if (rettv->v_type == VAR_STRING) {
@@ -3526,6 +3010,19 @@ static void f_glob2regpat(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   rettv->vval.v_string = (pat == NULL) ? NULL : file_pat_to_reg_pat(pat, NULL, NULL, false);
 }
 
+/// "gettext()" function
+static void f_gettext(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  if (argvars[0].v_type != VAR_STRING
+      || argvars[0].vval.v_string == NULL
+      || *argvars[0].vval.v_string == NUL) {
+    semsg(_(e_invarg2), tv_get_string(&argvars[0]));
+  } else {
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = xstrdup(_(argvars[0].vval.v_string));
+  }
+}
+
 /// "has()" function
 static void f_has(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -3542,7 +3039,7 @@ static void f_has(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 #ifdef UNIX
     "unix",
 #endif
-#if defined(MSWIN)
+#ifdef MSWIN
     "win32",
 #endif
 #ifdef _WIN64
@@ -3565,7 +3062,6 @@ static void f_has(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     "cmdwin",
     "comments",
     "conceal",
-    "cscope",
     "cursorbind",
     "cursorshape",
 #ifdef DEBUG
@@ -3586,9 +3082,7 @@ static void f_has(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     "fork",
 #endif
     "gettext",
-#if defined(HAVE_ICONV)
     "iconv",
-#endif
     "insert_expand",
     "jumplist",
     "keymap",
@@ -3616,8 +3110,6 @@ static void f_has(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     "packages",
     "path_extra",
     "persistent_undo",
-    "postscript",
-    "printer",
     "profile",
     "pythonx",
     "reltime",
@@ -3634,7 +3126,7 @@ static void f_has(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     "spell",
     "syntax",
 #if !defined(UNIX)
-    "system",  // TODO(SplinterOfChaos): This IS defined for UNIX!
+    "system",
 #endif
     "tablineat",
     "tag_binary",
@@ -3870,13 +3362,11 @@ static void f_iconv(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
   const char *const str = tv_get_string(&argvars[0]);
   char buf1[NUMBUFLEN];
-  char_u *const from =
-    (char_u *)enc_canonize(enc_skip((char *)tv_get_string_buf(&argvars[1], buf1)));
+  char *const from = enc_canonize(enc_skip((char *)tv_get_string_buf(&argvars[1], buf1)));
   char buf2[NUMBUFLEN];
-  char_u *const to =
-    (char_u *)enc_canonize(enc_skip((char *)tv_get_string_buf(&argvars[2], buf2)));
+  char *const to = enc_canonize(enc_skip((char *)tv_get_string_buf(&argvars[2], buf2)));
   vimconv.vc_type = CONV_NONE;
-  convert_setup(&vimconv, (char *)from, (char *)to);
+  convert_setup(&vimconv, from, to);
 
   // If the encodings are equal, no conversion needed.
   if (vimconv.vc_type == CONV_NONE) {
@@ -3942,33 +3432,36 @@ static void f_index(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     emsg(_(e_listblobreq));
     return;
   }
+
   list_T *const l = argvars[0].vval.v_list;
-  if (l != NULL) {
-    listitem_T *item = tv_list_first(l);
-    if (argvars[2].v_type != VAR_UNKNOWN) {
-      bool error = false;
+  if (l == NULL) {
+    return;
+  }
 
-      // Start at specified item.
-      idx = tv_list_uidx(l, (int)tv_get_number_chk(&argvars[2], &error));
-      if (error || idx == -1) {
+  listitem_T *item = tv_list_first(l);
+  if (argvars[2].v_type != VAR_UNKNOWN) {
+    bool error = false;
+
+    // Start at specified item.
+    idx = tv_list_uidx(l, (int)tv_get_number_chk(&argvars[2], &error));
+    if (error || idx == -1) {
+      item = NULL;
+    } else {
+      item = tv_list_find(l, (int)idx);
+      assert(item != NULL);
+    }
+    if (argvars[3].v_type != VAR_UNKNOWN) {
+      ic = !!tv_get_number_chk(&argvars[3], &error);
+      if (error) {
         item = NULL;
-      } else {
-        item = tv_list_find(l, (int)idx);
-        assert(item != NULL);
-      }
-      if (argvars[3].v_type != VAR_UNKNOWN) {
-        ic = !!tv_get_number_chk(&argvars[3], &error);
-        if (error) {
-          item = NULL;
-        }
       }
     }
+  }
 
-    for (; item != NULL; item = TV_LIST_ITEM_NEXT(l, item), idx++) {
-      if (tv_equal(TV_LIST_ITEM_TV(item), &argvars[1], ic, false)) {
-        rettv->vval.v_number = idx;
-        break;
-      }
+  for (; item != NULL; item = TV_LIST_ITEM_NEXT(l, item), idx++) {
+    if (tv_equal(TV_LIST_ITEM_TV(item), &argvars[1], ic, false)) {
+      rettv->vval.v_number = idx;
+      break;
     }
   }
 }
@@ -4061,8 +3554,8 @@ static void f_insert(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     blob_T *const b = argvars[0].vval.v_blob;
 
     if (b == NULL
-        || var_check_lock(b->bv_lock, N_("insert() argument"),
-                          TV_TRANSLATE)) {
+        || value_check_lock(b->bv_lock, N_("insert() argument"),
+                            TV_TRANSLATE)) {
       return;
     }
 
@@ -4089,16 +3582,16 @@ static void f_insert(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     }
 
     ga_grow(&b->bv_ga, 1);
-    char_u *const p = (char_u *)b->bv_ga.ga_data;
+    uint8_t *const p = (uint8_t *)b->bv_ga.ga_data;
     memmove(p + before + 1, p + before, (size_t)(len - before));
-    *(p + before) = (char_u)val;
+    *(p + before) = (uint8_t)val;
     b->bv_ga.ga_len++;
 
     tv_copy(&argvars[0], rettv);
   } else if (argvars[0].v_type != VAR_LIST) {
     semsg(_(e_listblobarg), "insert()");
-  } else if (!var_check_lock(tv_list_locked((l = argvars[0].vval.v_list)),
-                             N_("insert() argument"), TV_TRANSLATE)) {
+  } else if (!value_check_lock(tv_list_locked((l = argvars[0].vval.v_list)),
+                               N_("insert() argument"), TV_TRANSLATE)) {
     long before = 0;
     if (argvars[2].v_type != VAR_UNKNOWN) {
       before = tv_get_number_chk(&argvars[2], &error);
@@ -4148,11 +3641,11 @@ static void f_islocked(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   lval_T lv;
 
   rettv->vval.v_number = -1;
-  const char_u *const end = (char_u *)get_lval((char *)tv_get_string(&argvars[0]),
-                                               NULL,
-                                               &lv, false, false,
-                                               GLV_NO_AUTOLOAD|GLV_READ_ONLY,
-                                               FNE_CHECK_START);
+  const char *const end = get_lval((char *)tv_get_string(&argvars[0]),
+                                   NULL,
+                                   &lv, false, false,
+                                   GLV_NO_AUTOLOAD|GLV_READ_ONLY,
+                                   FNE_CHECK_START);
   if (end != NULL && lv.ll_name != NULL) {
     if (*end != NUL) {
       semsg(_(e_trailing_arg), end);
@@ -4880,9 +4373,9 @@ static void f_map(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 static void find_some_match(typval_T *const argvars, typval_T *const rettv,
                             const SomeMatchType type)
 {
-  char_u *str = NULL;
+  char *str = NULL;
   long len = 0;
-  char_u *expr = NULL;
+  char *expr = NULL;
   regmatch_T regmatch;
   long start = 0;
   long nth = 1;
@@ -4890,7 +4383,7 @@ static void find_some_match(typval_T *const argvars, typval_T *const rettv,
   bool match = false;
   list_T *l = NULL;
   long idx = 0;
-  char_u *tofree = NULL;
+  char *tofree = NULL;
 
   // Make 'cpoptions' empty, the 'l' flag should not be used here.
   char *save_cpo = p_cpo;
@@ -4927,8 +4420,8 @@ static void find_some_match(typval_T *const argvars, typval_T *const rettv,
     }
     li = tv_list_first(l);
   } else {
-    expr = str = (char_u *)tv_get_string(&argvars[0]);
-    len = (long)STRLEN(str);
+    expr = str = (char *)tv_get_string(&argvars[0]);
+    len = (long)strlen(str);
   }
 
   char patbuf[NUMBUFLEN];
@@ -4987,8 +4480,7 @@ static void find_some_match(typval_T *const argvars, typval_T *const rettv,
           break;
         }
         xfree(tofree);
-        tofree = expr = str = (char_u *)encode_tv2echo(TV_LIST_ITEM_TV(li),
-                                                       NULL);
+        tofree = expr = str = encode_tv2echo(TV_LIST_ITEM_TV(li), NULL);
         if (str == NULL) {
           break;
         }
@@ -5008,9 +4500,9 @@ static void find_some_match(typval_T *const argvars, typval_T *const rettv,
         li = TV_LIST_ITEM_NEXT(l, li);
         idx++;
       } else {
-        startcol = (colnr_T)((char_u *)regmatch.startp[0]
+        startcol = (colnr_T)(regmatch.startp[0]
                              + utfc_ptr2len(regmatch.startp[0]) - str);
-        if (startcol > (colnr_T)len || str + startcol <= (char_u *)regmatch.startp[0]) {
+        if (startcol > (colnr_T)len || str + startcol <= regmatch.startp[0]) {
           match = false;
           break;
         }
@@ -5028,9 +4520,9 @@ static void find_some_match(typval_T *const argvars, typval_T *const rettv,
         xfree(TV_LIST_ITEM_TV(li1)->vval.v_string);
 
         const size_t rd = (size_t)(regmatch.endp[0] - regmatch.startp[0]);
-        TV_LIST_ITEM_TV(li1)->vval.v_string = xmemdupz((const char *)regmatch.startp[0], rd);
-        TV_LIST_ITEM_TV(li3)->vval.v_number = (varnumber_T)((char_u *)regmatch.startp[0] - expr);
-        TV_LIST_ITEM_TV(li4)->vval.v_number = (varnumber_T)(regmatch.endp[0] - (char *)expr);
+        TV_LIST_ITEM_TV(li1)->vval.v_string = xmemdupz(regmatch.startp[0], rd);
+        TV_LIST_ITEM_TV(li3)->vval.v_number = (varnumber_T)(regmatch.startp[0] - expr);
+        TV_LIST_ITEM_TV(li4)->vval.v_number = (varnumber_T)(regmatch.endp[0] - expr);
         if (l != NULL) {
           TV_LIST_ITEM_TV(li2)->vval.v_number = (varnumber_T)idx;
         }
@@ -5064,11 +4556,9 @@ static void find_some_match(typval_T *const argvars, typval_T *const rettv,
           rettv->vval.v_number = idx;
         } else {
           if (type == kSomeMatch) {
-            rettv->vval.v_number =
-              (varnumber_T)((char_u *)regmatch.startp[0] - str);
+            rettv->vval.v_number = (varnumber_T)(regmatch.startp[0] - str);
           } else {
-            rettv->vval.v_number =
-              (varnumber_T)(regmatch.endp[0] - (char *)str);
+            rettv->vval.v_number = (varnumber_T)(regmatch.endp[0] - str);
           }
           rettv->vval.v_number += (varnumber_T)(str - expr);
         }
@@ -5142,7 +4632,7 @@ static void max_min(const typval_T *const tv, typval_T *const rettv, const bool
     TV_LIST_ITER_CONST(tv->vval.v_list, li, {
       const varnumber_T i = tv_get_number_chk(TV_LIST_ITEM_TV(li), &error);
       if (error) {
-        return;
+        return;  // type error; errmsg already given
       }
       if (domax ? i > n : i < n) {
         n = i;
@@ -5155,7 +4645,7 @@ static void max_min(const typval_T *const tv, typval_T *const rettv, const bool
     TV_DICT_ITER(tv->vval.v_dict, di, {
       const varnumber_T i = tv_get_number_chk(&di->di_tv, &error);
       if (error) {
-        return;
+        return;  // type error; errmsg already given
       }
       if (domax ? i > n : i < n) {
         n = i;
@@ -5165,6 +4655,7 @@ static void max_min(const typval_T *const tv, typval_T *const rettv, const bool
     semsg(_(e_listdictarg), domax ? "max()" : "min()");
     return;
   }
+
   rettv->vval.v_number = n;
 }
 
@@ -5216,10 +4707,9 @@ static void f_mkdir(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
         xfree(failed_dir);
         rettv->vval.v_number = FAIL;
         return;
-      } else {
-        rettv->vval.v_number = OK;
-        return;
       }
+      rettv->vval.v_number = OK;
+      return;
     }
   }
   rettv->vval.v_number = vim_mkdir_emsg(dir, prot);
@@ -5470,7 +4960,7 @@ static void f_pathshorten(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     rettv->vval.v_string = NULL;
   } else {
     rettv->vval.v_string = xstrdup(p);
-    shorten_dir_len((char_u *)rettv->vval.v_string, trim_len);
+    shorten_dir_len(rettv->vval.v_string, trim_len);
   }
 }
 
@@ -5657,10 +5147,11 @@ static void init_srand(uint32_t *const x)
     }
   }
   if (dev_urandom_state != OK) {
-    // Reading /dev/urandom doesn't work, fall back to time().
+    // Reading /dev/urandom doesn't work, fall back to os_hrtime() XOR with process ID
 #endif
   // uncrustify:off
-    *x = (uint32_t)time(NULL);
+    *x = (uint32_t)os_hrtime();
+    *x ^= (uint32_t)os_get_pid();
 #ifndef MSWIN
   }
 #endif
@@ -5820,13 +5311,16 @@ static void f_range(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   }
   if (stride == 0) {
     emsg(_("E726: Stride is zero"));
-  } else if (stride > 0 ? end + 1 < start : end - 1 > start) {
+    return;
+  }
+  if (stride > 0 ? end + 1 < start : end - 1 > start) {
     emsg(_("E727: Start past end"));
-  } else {
-    tv_list_alloc_ret(rettv, (end - start) / stride);
-    for (varnumber_T i = start; stride > 0 ? i <= end : i >= end; i += stride) {
-      tv_list_append_number(rettv->vval.v_list, i);
-    }
+    return;
+  }
+
+  tv_list_alloc_ret(rettv, (end - start) / stride);
+  for (varnumber_T i = start; stride > 0 ? i <= end : i >= end; i += stride) {
+    tv_list_append_number(rettv->vval.v_list, i);
   }
 }
 
@@ -5885,17 +5379,17 @@ static void f_readdir(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   ga_clear_strings(&ga);
 }
 
-/// "readfile()" function
-static void f_readfile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+/// "readfile()" or "readblob()" function
+static void read_file_or_blob(typval_T *argvars, typval_T *rettv, bool always_blob)
 {
   bool binary = false;
-  bool blob = false;
+  bool blob = always_blob;
   FILE *fd;
   char buf[(IOSIZE/256) * 256];    // rounded to avoid odd + 1
   int io_size = sizeof(buf);
   char *prev = NULL;               // previously read bytes, if any
-  long prevlen  = 0;               // length of data in prev
-  long prevsize = 0;               // size of prev buffer
+  ptrdiff_t prevlen  = 0;               // length of data in prev
+  ptrdiff_t prevsize = 0;               // size of prev buffer
   long maxline  = MAXLNUM;
 
   if (argvars[1].v_type != VAR_UNKNOWN) {
@@ -5949,7 +5443,7 @@ static void f_readfile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     for (p = buf, start = buf;
          p < buf + readlen || (readlen <= 0 && (prevlen > 0 || binary));
          p++) {
-      if (*p == '\n' || readlen <= 0) {
+      if (readlen <= 0 || *p == '\n') {
         char *s  = NULL;
         size_t len = (size_t)(p - start);
 
@@ -6024,8 +5518,8 @@ static void f_readfile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
             int adjust_prevlen = 0;
 
             if (dest < buf) {  // -V782
-              adjust_prevlen = (int)(buf - dest);  // -V782
               // adjust_prevlen must be 1 or 2.
+              adjust_prevlen = (int)(buf - dest);  // -V782
               dest = buf;
             }
             if (readlen > p - buf + 1) {
@@ -6050,17 +5544,17 @@ static void f_readfile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
         // small, to avoid repeatedly 'allocing' large and
         // 'reallocing' small.
         if (prevsize == 0) {
-          prevsize = (long)(p - start);
+          prevsize = p - start;
         } else {
-          long grow50pc = (prevsize * 3) / 2;
-          long growmin  = (long)((p - start) * 2 + prevlen);
+          ptrdiff_t grow50pc = (prevsize * 3) / 2;
+          ptrdiff_t growmin  = (p - start) * 2 + prevlen;
           prevsize = grow50pc > growmin ? grow50pc : growmin;
         }
         prev = xrealloc(prev, (size_t)prevsize);
       }
       // Add the line part to end of "prev".
       memmove(prev + prevlen, start, (size_t)(p - start));
-      prevlen += (long)(p - start);
+      prevlen += p - start;
     }
   }   // while
 
@@ -6068,6 +5562,18 @@ static void f_readfile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   fclose(fd);
 }
 
+/// "readblob()" function
+static void f_readblob(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  read_file_or_blob(argvars, rettv, true);
+}
+
+/// "readfile()" function
+static void f_readfile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  read_file_or_blob(argvars, rettv, false);
+}
+
 /// "getreginfo()" function
 static void f_getreginfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -6377,7 +5883,7 @@ static void f_resolve(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
           q[-1] = NUL;
           q = path_tail(p);
         }
-        if (q > p && !path_is_absolute((const char_u *)buf)) {
+        if (q > p && !path_is_absolute(buf)) {
           // Symlink is relative to directory of argument. Replace the
           // symlink with the resolved name in the same directory.
           const size_t p_len = strlen(p);
@@ -6457,7 +5963,7 @@ static void f_resolve(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 # endif
 #endif
 
-  simplify_filename((char_u *)rettv->vval.v_string);
+  simplify_filename(rettv->vval.v_string);
 }
 
 /// "reverse({list})" function
@@ -6468,7 +5974,7 @@ static void f_reverse(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     const int len = tv_blob_len(b);
 
     for (int i = 0; i < len / 2; i++) {
-      const char_u tmp = tv_blob_get(b, i);
+      const uint8_t tmp = tv_blob_get(b, i);
       tv_blob_set(b, i, tv_blob_get(b, len - i - 1));
       tv_blob_set(b, len - i - 1, tmp);
     }
@@ -6477,8 +5983,8 @@ static void f_reverse(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     semsg(_(e_listblobarg), "reverse()");
   } else {
     list_T *const l = argvars[0].vval.v_list;
-    if (!var_check_lock(tv_list_locked(l), N_("reverse() argument"),
-                        TV_TRANSLATE)) {
+    if (!value_check_lock(tv_list_locked(l), N_("reverse() argument"),
+                          TV_TRANSLATE)) {
       tv_list_reverse(l);
       tv_list_set_ret(rettv, l);
     }
@@ -6598,55 +6104,57 @@ static int get_search_arg(typval_T *varp, int *flagsp)
 {
   int dir = FORWARD;
 
-  if (varp->v_type != VAR_UNKNOWN) {
-    char nbuf[NUMBUFLEN];
-    const char *flags = tv_get_string_buf_chk(varp, nbuf);
-    if (flags == NULL) {
-      return 0;  // Type error; errmsg already given.
-    }
-    int mask;
-    while (*flags != NUL) {
-      switch (*flags) {
-      case 'b':
-        dir = BACKWARD; break;
-      case 'w':
-        p_ws = true; break;
-      case 'W':
-        p_ws = false; break;
-      default:
-        mask = 0;
-        if (flagsp != NULL) {
-          switch (*flags) {
-          case 'c':
-            mask = SP_START; break;
-          case 'e':
-            mask = SP_END; break;
-          case 'm':
-            mask = SP_RETCOUNT; break;
-          case 'n':
-            mask = SP_NOMOVE; break;
-          case 'p':
-            mask = SP_SUBPAT; break;
-          case 'r':
-            mask = SP_REPEAT; break;
-          case 's':
-            mask = SP_SETPCMARK; break;
-          case 'z':
-            mask = SP_COLUMN; break;
-          }
-        }
-        if (mask == 0) {
-          semsg(_(e_invarg2), flags);
-          dir = 0;
-        } else {
-          *flagsp |= mask;
+  if (varp->v_type == VAR_UNKNOWN) {
+    return FORWARD;
+  }
+
+  char nbuf[NUMBUFLEN];
+  const char *flags = tv_get_string_buf_chk(varp, nbuf);
+  if (flags == NULL) {
+    return 0;  // Type error; errmsg already given.
+  }
+  int mask;
+  while (*flags != NUL) {
+    switch (*flags) {
+    case 'b':
+      dir = BACKWARD; break;
+    case 'w':
+      p_ws = true; break;
+    case 'W':
+      p_ws = false; break;
+    default:
+      mask = 0;
+      if (flagsp != NULL) {
+        switch (*flags) {
+        case 'c':
+          mask = SP_START; break;
+        case 'e':
+          mask = SP_END; break;
+        case 'm':
+          mask = SP_RETCOUNT; break;
+        case 'n':
+          mask = SP_NOMOVE; break;
+        case 'p':
+          mask = SP_SUBPAT; break;
+        case 'r':
+          mask = SP_REPEAT; break;
+        case 's':
+          mask = SP_SETPCMARK; break;
+        case 'z':
+          mask = SP_COLUMN; break;
         }
       }
-      if (dir == 0) {
-        break;
+      if (mask == 0) {
+        semsg(_(e_invarg2), flags);
+        dir = 0;
+      } else {
+        *flagsp |= mask;
       }
-      flags++;
     }
+    if (dir == 0) {
+      break;
+    }
+    flags++;
   }
   return dir;
 }
@@ -6718,7 +6226,7 @@ static int search_cmn(typval_T *argvars, pos_T *match_pos, int *flagsp)
   // Repeat until {skip} returns false.
   for (;;) {
     subpatnum
-      = searchit(curwin, curbuf, &pos, NULL, dir, (char_u *)pat, 1, options, RE_SEARCH, &sia);
+      = searchit(curwin, curbuf, &pos, NULL, dir, (char *)pat, 1, options, RE_SEARCH, &sia);
     // finding the first match again means there is no match where {skip}
     // evaluates to zero.
     if (firstpos.lnum != 0 && equalpos(pos, firstpos)) {
@@ -6729,7 +6237,9 @@ static int search_cmn(typval_T *argvars, pos_T *match_pos, int *flagsp)
       // didn't find it or no skip argument
       break;
     }
-    firstpos = pos;
+    if (firstpos.lnum == 0) {
+      firstpos = pos;
+    }
 
     // If the skip expression matches, ignore this match.
     {
@@ -6811,12 +6321,15 @@ static void f_rpcnotify(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     ADD(args, vim_to_object(tv));
   }
 
-  if (!rpc_send_event((uint64_t)argvars[0].vval.v_number,
-                      tv_get_string(&argvars[1]), args)) {
+  bool ok = rpc_send_event((uint64_t)argvars[0].vval.v_number,
+                           tv_get_string(&argvars[1]), args);
+
+  api_free_array(args);
+
+  if (!ok) {
     semsg(_(e_invarg2), "Channel doesn't exist");
     return;
   }
-
   rettv->vval.v_number = 1;
 }
 
@@ -6955,7 +6468,7 @@ static void f_rpcstart(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
   // Allocate extra memory for the argument vector and the NULL pointer
   int argvl = argsl + 2;
-  char **argv = xmalloc(sizeof(char_u *) * (size_t)argvl);
+  char **argv = xmalloc(sizeof(char *) * (size_t)argvl);
 
   // Copy program name
   argv[0] = xstrdup(argvars[0].vval.v_string);
@@ -7131,7 +6644,7 @@ static void f_searchdecl(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     }
   }
   if (!error && name != NULL) {
-    rettv->vval.v_number = find_decl((char_u *)name, strlen(name), locally,
+    rettv->vval.v_number = find_decl((char *)name, strlen(name), locally,
                                      thisblock, SEARCH_KEEP) == FAIL;
   }
 }
@@ -7266,14 +6779,14 @@ long do_searchpair(const char *spat, const char *mpat, const char *epat, int dir
   // Make two search patterns: start/end (pat2, for in nested pairs) and
   // start/middle/end (pat3, for the top pair).
   const size_t pat2_len = strlen(spat) + strlen(epat) + 17;
-  char_u *pat2 = xmalloc(pat2_len);
+  char *pat2 = xmalloc(pat2_len);
   const size_t pat3_len = strlen(spat) + strlen(mpat) + strlen(epat) + 25;
-  char_u *pat3 = xmalloc(pat3_len);
-  snprintf((char *)pat2, pat2_len, "\\m\\(%s\\m\\)\\|\\(%s\\m\\)", spat, epat);
+  char *pat3 = xmalloc(pat3_len);
+  snprintf(pat2, pat2_len, "\\m\\(%s\\m\\)\\|\\(%s\\m\\)", spat, epat);
   if (*mpat == NUL) {
     STRCPY(pat3, pat2);
   } else {
-    snprintf((char *)pat3, pat3_len,
+    snprintf(pat3, pat3_len,
              "\\m\\(%s\\m\\)\\|\\(%s\\m\\)\\|\\(%s\\m\\)", spat, epat, mpat);
   }
   if (flags & SP_START) {
@@ -7290,7 +6803,7 @@ long do_searchpair(const char *spat, const char *mpat, const char *epat, int dir
   clearpos(&firstpos);
   pos_T foundpos;
   clearpos(&foundpos);
-  char_u *pat = pat3;
+  char *pat = pat3;
   for (;;) {
     searchit_arg_T sia = {
       .sa_stop_lnum = lnum_stop,
@@ -7449,9 +6962,8 @@ static void f_serverstart(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     if (argvars[0].v_type != VAR_STRING) {
       emsg(_(e_invarg));
       return;
-    } else {
-      address = xstrdup(tv_get_string(argvars));
     }
+    address = xstrdup(tv_get_string(argvars));
   } else {
     address = server_address_new(NULL);
   }
@@ -7498,21 +7010,6 @@ static void f_serverstop(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   }
 }
 
-/// "setbufline()" function
-static void f_setbufline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  linenr_T lnum;
-  buf_T *buf;
-
-  buf = tv_get_buf(&argvars[0], false);
-  if (buf == NULL) {
-    rettv->vval.v_number = 1;  // FAIL
-  } else {
-    lnum = tv_get_lnum_buf(&argvars[1], buf);
-    set_buffer_lines(buf, lnum, false, &argvars[2], rettv);
-  }
-}
-
 /// Set the cursor or mark position.
 /// If 'charpos' is true, then use the column number as a character offset.
 /// Otherwise use the column number as a byte offset.
@@ -7522,31 +7019,35 @@ static void set_position(typval_T *argvars, typval_T *rettv, bool charpos)
 
   rettv->vval.v_number = -1;
   const char *const name = tv_get_string_chk(argvars);
-  if (name != NULL) {
-    pos_T pos;
-    int fnum;
-    if (list2fpos(&argvars[1], &pos, &fnum, &curswant, charpos) == OK) {
-      if (pos.col != MAXCOL && --pos.col < 0) {
-        pos.col = 0;
-      }
-      if (name[0] == '.' && name[1] == NUL) {
-        // set cursor; "fnum" is ignored
-        curwin->w_cursor = pos;
-        if (curswant >= 0) {
-          curwin->w_curswant = curswant - 1;
-          curwin->w_set_curswant = false;
-        }
-        check_cursor();
-        rettv->vval.v_number = 0;
-      } else if (name[0] == '\'' && name[1] != NUL && name[2] == NUL) {
-        // set mark
-        if (setmark_pos((uint8_t)name[1], &pos, fnum, NULL) == OK) {
-          rettv->vval.v_number = 0;
-        }
-      } else {
-        emsg(_(e_invarg));
-      }
+  if (name == NULL) {
+    return;
+  }
+
+  pos_T pos;
+  int fnum;
+  if (list2fpos(&argvars[1], &pos, &fnum, &curswant, charpos) != OK) {
+    return;
+  }
+
+  if (pos.col != MAXCOL && --pos.col < 0) {
+    pos.col = 0;
+  }
+  if (name[0] == '.' && name[1] == NUL) {
+    // set cursor; "fnum" is ignored
+    curwin->w_cursor = pos;
+    if (curswant >= 0) {
+      curwin->w_curswant = curswant - 1;
+      curwin->w_set_curswant = false;
+    }
+    check_cursor();
+    rettv->vval.v_number = 0;
+  } else if (name[0] == '\'' && name[1] != NUL && name[2] == NUL) {
+    // set mark
+    if (setmark_pos((uint8_t)name[1], &pos, fnum, NULL) == OK) {
+      rettv->vval.v_number = 0;
     }
+  } else {
+    emsg(_(e_invarg));
   }
 }
 
@@ -7564,23 +7065,25 @@ static void f_setcharsearch(typval_T *argvars, typval_T *rettv, EvalFuncData fpt
   }
 
   dict_T *d = argvars[0].vval.v_dict;
-  if (d != NULL) {
-    char_u *const csearch = (char_u *)tv_dict_get_string(d, "char", false);
-    if (csearch != NULL) {
-      int pcc[MAX_MCO];
-      const int c = utfc_ptr2char((char *)csearch, pcc);
-      set_last_csearch(c, csearch, utfc_ptr2len((char *)csearch));
-    }
+  if (d == NULL) {
+    return;
+  }
 
-    dictitem_T *di = tv_dict_find(d, S_LEN("forward"));
-    if (di != NULL) {
-      set_csearch_direction(tv_get_number(&di->di_tv) ? FORWARD : BACKWARD);
-    }
+  char *const csearch = tv_dict_get_string(d, "char", false);
+  if (csearch != NULL) {
+    int pcc[MAX_MCO];
+    const int c = utfc_ptr2char(csearch, pcc);
+    set_last_csearch(c, csearch, utfc_ptr2len(csearch));
+  }
 
-    di = tv_dict_find(d, S_LEN("until"));
-    if (di != NULL) {
-      set_csearch_until(!!tv_get_number(&di->di_tv));
-    }
+  dictitem_T *di = tv_dict_find(d, S_LEN("forward"));
+  if (di != NULL) {
+    set_csearch_direction(tv_get_number(&di->di_tv) ? FORWARD : BACKWARD);
+  }
+
+  di = tv_dict_find(d, S_LEN("until"));
+  if (di != NULL) {
+    set_csearch_until(!!tv_get_number(&di->di_tv));
   }
 }
 
@@ -7636,13 +7139,6 @@ static void f_setfperm(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   rettv->vval.v_number = os_setperm(fname, mode) == OK;
 }
 
-/// "setline()" function
-static void f_setline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  linenr_T lnum = tv_get_lnum(&argvars[0]);
-  set_buffer_lines(curbuf, lnum, false, &argvars[1], rettv);
-}
-
 /// "setpos()" function
 static void f_setpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -7888,8 +7384,7 @@ static void f_shellescape(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   const bool do_special = non_zero_arg(&argvars[1]);
 
   rettv->vval.v_string =
-    (char *)vim_strsave_shellescape((const char_u *)tv_get_string(&argvars[0]), do_special,
-                                    do_special);
+    vim_strsave_shellescape(tv_get_string(&argvars[0]), do_special, do_special);
   rettv->v_type = VAR_STRING;
 }
 
@@ -7914,7 +7409,7 @@ static void f_simplify(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
   const char *const p = tv_get_string(&argvars[0]);
   rettv->vval.v_string = xstrdup(p);
-  simplify_filename((char_u *)rettv->vval.v_string);  // Simplify in place.
+  simplify_filename(rettv->vval.v_string);  // Simplify in place.
   rettv->v_type = VAR_STRING;
 }
 
@@ -8058,7 +7553,7 @@ static void f_spellbadword(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
     if (str != NULL) {
       // Check the argument for spelling.
       while (*str != NUL) {
-        len = spell_check(curwin, (char_u *)str, &attr, &capcol, false);
+        len = spell_check(curwin, (char *)str, &attr, &capcol, false);
         if (attr != HLF_COUNT) {
           word = str;
           break;
@@ -8117,7 +7612,7 @@ static void f_spellsuggest(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
     maxcount = 25;
   }
 
-  spell_suggest_list(&ga, (char_u *)str, maxcount, need_capital, false);
+  spell_suggest_list(&ga, (char *)str, maxcount, need_capital, false);
 
 f_spellsuggest_return:
   tv_list_alloc_ret(rettv, (ptrdiff_t)ga.ga_len);
@@ -8148,7 +7643,7 @@ static void f_split(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       typeerr = true;
     }
     if (argvars[2].v_type != VAR_UNKNOWN) {
-      keepempty = (bool)tv_get_number_chk(&argvars[2], &typeerr);
+      keepempty = (bool)tv_get_bool_chk(&argvars[2], &typeerr);
     }
   }
   if (pat == NULL || *pat == NUL) {
@@ -8173,7 +7668,7 @@ static void f_split(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       if (*str == NUL) {
         match = false;  // Empty item at the end.
       } else {
-        match = vim_regexec_nl(&regmatch, (char_u *)str, col);
+        match = vim_regexec_nl(&regmatch, (char *)str, col);
       }
       const char *end;
       if (match) {
@@ -8259,10 +7754,10 @@ static void f_str2float(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 static void f_str2list(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
   tv_list_alloc_ret(rettv, kListLenUnknown);
-  const char_u *p = (const char_u *)tv_get_string(&argvars[0]);
+  const char *p = tv_get_string(&argvars[0]);
 
-  for (; *p != NUL; p += utf_ptr2len((char *)p)) {
-    tv_list_append_number(rettv->vval.v_list, utf_ptr2char((char *)p));
+  for (; *p != NUL; p += utf_ptr2len(p)) {
+    tv_list_append_number(rettv->vval.v_list, utf_ptr2char(p));
   }
 }
 
@@ -8278,15 +7773,15 @@ static void f_str2nr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       emsg(_(e_invarg));
       return;
     }
-    if (argvars[2].v_type != VAR_UNKNOWN && tv_get_number(&argvars[2])) {
+    if (argvars[2].v_type != VAR_UNKNOWN && tv_get_bool(&argvars[2])) {
       what |= STR2NR_QUOTE;
     }
   }
 
-  char_u *p = (char_u *)skipwhite(tv_get_string(&argvars[0]));
+  char *p = skipwhite(tv_get_string(&argvars[0]));
   bool isneg = (*p == '-');
   if (*p == '+' || *p == '-') {
-    p = (char_u *)skipwhite((char *)p + 1);
+    p = skipwhite(p + 1);
   }
   switch (base) {
   case 2:
@@ -8300,7 +7795,7 @@ static void f_str2nr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     break;
   }
   varnumber_T n;
-  vim_str2nr((char *)p, NULL, NULL, what, &n, NULL, 0, false);
+  vim_str2nr(p, NULL, NULL, what, &n, NULL, 0, false);
   // Text after the number is silently ignored.
   if (isneg) {
     rettv->vval.v_number = -n;
@@ -8332,15 +7827,13 @@ static void f_strftime(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     vimconv_T conv;
 
     conv.vc_type = CONV_NONE;
-    char *enc = (char *)enc_locale();
+    char *enc = enc_locale();
     convert_setup(&conv, p_enc, enc);
     if (conv.vc_type != CONV_NONE) {
       p = string_convert(&conv, p, NULL);
     }
     char result_buf[256];
-    if (p != NULL) {
-      (void)strftime(result_buf, sizeof(result_buf), p, curtime_ptr);
-    } else {
+    if (p == NULL || strftime(result_buf, sizeof(result_buf), p, curtime_ptr) == 0) {
       result_buf[0] = NUL;
     }
 
@@ -8433,26 +7926,38 @@ static void f_strlen(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   rettv->vval.v_number = (varnumber_T)strlen(tv_get_string(&argvars[0]));
 }
 
-/// "strchars()" function
-static void f_strchars(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+static void strchar_common(typval_T *argvars, typval_T *rettv, bool skipcc)
 {
   const char *s = tv_get_string(&argvars[0]);
-  int skipcc = 0;
   varnumber_T len = 0;
-  int (*func_mb_ptr2char_adv)(const char_u **pp);
+  int (*func_mb_ptr2char_adv)(const char **pp);
+
+  func_mb_ptr2char_adv = skipcc ? mb_ptr2char_adv : mb_cptr2char_adv;
+  while (*s != NUL) {
+    func_mb_ptr2char_adv(&s);
+    len++;
+  }
+  rettv->vval.v_number = len;
+}
+
+/// "strcharlen()" function
+static void f_strcharlen(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  strchar_common(argvars, rettv, true);
+}
+
+/// "strchars()" function
+static void f_strchars(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  int skipcc = false;
 
   if (argvars[1].v_type != VAR_UNKNOWN) {
-    skipcc = (int)tv_get_number_chk(&argvars[1], NULL);
+    skipcc = (int)tv_get_bool(&argvars[1]);
   }
   if (skipcc < 0 || skipcc > 1) {
-    emsg(_(e_invarg));
+    semsg(_(e_using_number_as_bool_nr), skipcc);
   } else {
-    func_mb_ptr2char_adv = skipcc ? mb_ptr2char_adv : mb_cptr2char_adv;
-    while (*s != NUL) {
-      func_mb_ptr2char_adv((const char_u **)&s);
-      len++;
-    }
-    rettv->vval.v_number = len;
+    strchar_common(argvars, rettv, skipcc);
   }
 }
 
@@ -8592,7 +8097,7 @@ static void f_strptime(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   vimconv_T conv = {
     .vc_type = CONV_NONE,
   };
-  char *enc = (char *)enc_locale();
+  char *enc = enc_locale();
   convert_setup(&conv, p_enc, enc);
   if (conv.vc_type != CONV_NONE) {
     fmt = string_convert(&conv, fmt, NULL);
@@ -8866,7 +8371,7 @@ static void f_synconcealed(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
   int syntax_flags = 0;
   int cchar;
   int matchid = 0;
-  char_u str[NUMBUFLEN];
+  char str[NUMBUFLEN];
 
   tv_list_set_ret(rettv, NULL);
 
@@ -8890,7 +8395,7 @@ static void f_synconcealed(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
           : curwin->w_p_lcs_chars.conceal;
       }
       if (cchar != NUL) {
-        utf_char2bytes(cchar, (char *)str);
+        utf_char2bytes(cchar, str);
       }
     }
   }
@@ -8898,7 +8403,7 @@ static void f_synconcealed(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
   tv_list_alloc_ret(rettv, 3);
   tv_list_append_number(rettv->vval.v_list, (syntax_flags & HL_CONCEAL) != 0);
   // -1 to auto-determine strlen
-  tv_list_append_string(rettv->vval.v_list, (const char *)str, -1);
+  tv_list_append_string(rettv->vval.v_list, str, -1);
   tv_list_append_number(rettv->vval.v_list, matchid);
 }
 
@@ -8959,105 +8464,6 @@ static void f_tabpagebuflist(typval_T *argvars, typval_T *rettv, EvalFuncData fp
   }
 }
 
-/// "tabpagenr()" function
-static void f_tabpagenr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  int nr = 1;
-
-  if (argvars[0].v_type != VAR_UNKNOWN) {
-    const char *const arg = tv_get_string_chk(&argvars[0]);
-    nr = 0;
-    if (arg != NULL) {
-      if (strcmp(arg, "$") == 0) {
-        nr = tabpage_index(NULL) - 1;
-      } else if (strcmp(arg, "#") == 0) {
-        nr = valid_tabpage(lastused_tabpage) ? tabpage_index(lastused_tabpage) : 0;
-      } else {
-        semsg(_(e_invexpr2), arg);
-      }
-    }
-  } else {
-    nr = tabpage_index(curtab);
-  }
-  rettv->vval.v_number = nr;
-}
-
-/// Common code for tabpagewinnr() and winnr().
-static int get_winnr(tabpage_T *tp, typval_T *argvar)
-{
-  int nr = 1;
-
-  win_T *twin = (tp == curtab) ? curwin : tp->tp_curwin;
-  if (argvar->v_type != VAR_UNKNOWN) {
-    bool invalid_arg = false;
-    const char *const arg = tv_get_string_chk(argvar);
-    if (arg == NULL) {
-      nr = 0;  // Type error; errmsg already given.
-    } else if (strcmp(arg, "$") == 0) {
-      twin = (tp == curtab) ? lastwin : tp->tp_lastwin;
-    } else if (strcmp(arg, "#") == 0) {
-      twin = (tp == curtab) ? prevwin : tp->tp_prevwin;
-      if (twin == NULL) {
-        nr = 0;
-      }
-    } else {
-      // Extract the window count (if specified). e.g. winnr('3j')
-      char *endp;
-      long count = strtol((char *)arg, &endp, 10);
-      if (count <= 0) {
-        // if count is not specified, default to 1
-        count = 1;
-      }
-      if (endp != NULL && *endp != '\0') {
-        if (strequal(endp, "j")) {
-          twin = win_vert_neighbor(tp, twin, false, count);
-        } else if (strequal(endp, "k")) {
-          twin = win_vert_neighbor(tp, twin, true, count);
-        } else if (strequal(endp, "h")) {
-          twin = win_horz_neighbor(tp, twin, true, count);
-        } else if (strequal(endp, "l")) {
-          twin = win_horz_neighbor(tp, twin, false, count);
-        } else {
-          invalid_arg = true;
-        }
-      } else {
-        invalid_arg = true;
-      }
-    }
-
-    if (invalid_arg) {
-      semsg(_(e_invexpr2), arg);
-      nr = 0;
-    }
-  }
-
-  if (nr > 0) {
-    for (win_T *wp = (tp == curtab) ? firstwin : tp->tp_firstwin;
-         wp != twin; wp = wp->w_next) {
-      if (wp == NULL) {
-        // didn't find it in this tabpage
-        nr = 0;
-        break;
-      }
-      nr++;
-    }
-  }
-  return nr;
-}
-
-/// "tabpagewinnr()" function
-static void f_tabpagewinnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  int nr = 1;
-  tabpage_T *const tp = find_tabpage((int)tv_get_number(&argvars[0]));
-  if (tp == NULL) {
-    nr = 0;
-  } else {
-    nr = get_winnr(tp, &argvars[1]);
-  }
-  rettv->vval.v_number = nr;
-}
-
 /// "tagfiles()" function
 static void f_tagfiles(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -9090,7 +8496,7 @@ static void f_taglist(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     fname = tv_get_string(&argvars[1]);
   }
   (void)get_tags(tv_list_alloc_ret(rettv, kListLenUnknown),
-                 (char_u *)tag_pattern, (char_u *)fname);
+                 (char *)tag_pattern, (char *)fname);
 }
 
 /// "tempname()" function
@@ -9184,9 +8590,9 @@ static void f_termopen(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   int pid = chan->stream.pty.process.pid;
 
   // "./…" => "/home/foo/…"
-  vim_FullName(cwd, (char *)NameBuff, sizeof(NameBuff), false);
+  vim_FullName(cwd, NameBuff, sizeof(NameBuff), false);
   // "/home/foo/…" => "~/…"
-  size_t len = home_replace(NULL, (char *)NameBuff, (char *)IObuff, sizeof(IObuff), true);
+  size_t len = home_replace(NULL, NameBuff, IObuff, sizeof(IObuff), true);
   // Trim slash.
   if (len != 1 && (IObuff[len - 1] == '\\' || IObuff[len - 1] == '/')) {
     IObuff[len - 1] = '\0';
@@ -9199,14 +8605,14 @@ static void f_termopen(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   }
 
   // Terminal URI: "term://$CWD//$PID:$CMD"
-  snprintf((char *)NameBuff, sizeof(NameBuff), "term://%s//%d:%s",
-           (char *)IObuff, pid, cmd);
+  snprintf(NameBuff, sizeof(NameBuff), "term://%s//%d:%s",
+           IObuff, pid, cmd);
   // at this point the buffer has no terminal instance associated yet, so unset
   // the 'swapfile' option to ensure no swap file will be created
   curbuf->b_p_swf = false;
 
   apply_autocmds(EVENT_BUFFILEPRE, NULL, NULL, false, curbuf);
-  (void)setfname(curbuf, (char *)NameBuff, NULL, true);
+  (void)setfname(curbuf, NameBuff, NULL, true);
   apply_autocmds(EVENT_BUFFILEPOST, NULL, NULL, false, curbuf);
 
   // Save the job id and pid in b:terminal_job_{id,pid}
@@ -9357,7 +8763,7 @@ static void f_tr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     int fromlen;
     for (const char *p = fromstr; *p != NUL; p += fromlen) {
       fromlen = utfc_ptr2len(p);
-      if (fromlen == inlen && STRNCMP(in_str, p, inlen) == 0) {
+      if (fromlen == inlen && strncmp(in_str, p, (size_t)inlen) == 0) {
         int tolen;
         for (p = tostr; *p != NUL; p += tolen) {
           tolen = utfc_ptr2len(p);
@@ -9612,276 +9018,6 @@ static void f_wildmenumode(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
   }
 }
 
-/// "win_findbuf()" function
-static void f_win_findbuf(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  tv_list_alloc_ret(rettv, kListLenMayKnow);
-  win_findbuf(argvars, rettv->vval.v_list);
-}
-
-/// "win_getid()" function
-static void f_win_getid(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  rettv->vval.v_number = win_getid(argvars);
-}
-
-/// "win_gettype(nr)" function
-static void f_win_gettype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  win_T *wp = curwin;
-
-  rettv->v_type = VAR_STRING;
-  rettv->vval.v_string = NULL;
-  if (argvars[0].v_type != VAR_UNKNOWN) {
-    wp = find_win_by_nr_or_id(&argvars[0]);
-    if (wp == NULL) {
-      rettv->vval.v_string = xstrdup("unknown");
-      return;
-    }
-  }
-  if (wp == aucmd_win) {
-    rettv->vval.v_string = xstrdup("autocmd");
-  } else if (wp->w_p_pvw) {
-    rettv->vval.v_string = xstrdup("preview");
-  } else if (wp->w_floating) {
-    rettv->vval.v_string = xstrdup("popup");
-  } else if (wp == curwin && cmdwin_type != 0) {
-    rettv->vval.v_string = xstrdup("command");
-  } else if (bt_quickfix(wp->w_buffer)) {
-    rettv->vval.v_string = xstrdup((wp->w_llist_ref != NULL ? "loclist" : "quickfix"));
-  }
-}
-
-/// "win_gotoid()" function
-static void f_win_gotoid(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  int id = (int)tv_get_number(&argvars[0]);
-
-  if (cmdwin_type != 0) {
-    emsg(_(e_cmdwin));
-    return;
-  }
-  FOR_ALL_TAB_WINDOWS(tp, wp) {
-    if (wp->handle == id) {
-      goto_tabpage_win(tp, wp);
-      rettv->vval.v_number = 1;
-      return;
-    }
-  }
-}
-
-/// "win_id2tabwin()" function
-static void f_win_id2tabwin(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  win_id2tabwin(argvars, rettv);
-}
-
-/// "win_id2win()" function
-static void f_win_id2win(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  rettv->vval.v_number = win_id2win(argvars);
-}
-
-/// "win_move_separator()" function
-static void f_win_move_separator(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  rettv->vval.v_number = false;
-
-  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
-  if (wp == NULL || wp->w_floating) {
-    return;
-  }
-
-  int offset = (int)tv_get_number(&argvars[1]);
-  win_drag_vsep_line(wp, offset);
-  rettv->vval.v_number = true;
-}
-
-/// "win_move_statusline()" function
-static void f_win_move_statusline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  win_T *wp;
-  int offset;
-
-  rettv->vval.v_number = false;
-
-  wp = find_win_by_nr_or_id(&argvars[0]);
-  if (wp == NULL || wp->w_floating) {
-    return;
-  }
-
-  offset = (int)tv_get_number(&argvars[1]);
-  win_drag_status_line(wp, offset);
-  rettv->vval.v_number = true;
-}
-
-/// "winbufnr(nr)" function
-static void f_winbufnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
-  if (wp == NULL) {
-    rettv->vval.v_number = -1;
-  } else {
-    rettv->vval.v_number = wp->w_buffer->b_fnum;
-  }
-}
-
-/// "wincol()" function
-static void f_wincol(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  validate_cursor();
-  rettv->vval.v_number = curwin->w_wcol + 1;
-}
-
-/// "winheight(nr)" function
-static void f_winheight(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
-  if (wp == NULL) {
-    rettv->vval.v_number = -1;
-  } else {
-    rettv->vval.v_number = wp->w_height_inner;
-  }
-}
-
-/// "winlayout()" function
-static void f_winlayout(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  tabpage_T *tp;
-
-  tv_list_alloc_ret(rettv, 2);
-
-  if (argvars[0].v_type == VAR_UNKNOWN) {
-    tp = curtab;
-  } else {
-    tp = find_tabpage((int)tv_get_number(&argvars[0]));
-    if (tp == NULL) {
-      return;
-    }
-  }
-
-  get_framelayout(tp->tp_topframe, rettv->vval.v_list, true);
-}
-
-/// "winline()" function
-static void f_winline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  validate_cursor();
-  rettv->vval.v_number = curwin->w_wrow + 1;
-}
-
-/// "winnr()" function
-static void f_winnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  rettv->vval.v_number = get_winnr(curtab, &argvars[0]);
-}
-
-/// "winrestcmd()" function
-static void f_winrestcmd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  char_u buf[50];
-
-  garray_T ga;
-  ga_init(&ga, (int)sizeof(char), 70);
-
-  // Do this twice to handle some window layouts properly.
-  for (int i = 0; i < 2; i++) {
-    int winnr = 1;
-    FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
-      snprintf((char *)buf, sizeof(buf), "%dresize %d|", winnr,
-               wp->w_height);
-      ga_concat(&ga, (char *)buf);
-      snprintf((char *)buf, sizeof(buf), "vert %dresize %d|", winnr,
-               wp->w_width);
-      ga_concat(&ga, (char *)buf);
-      winnr++;
-    }
-  }
-  ga_append(&ga, NUL);
-
-  rettv->vval.v_string = ga.ga_data;
-  rettv->v_type = VAR_STRING;
-}
-
-/// "winrestview()" function
-static void f_winrestview(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  dict_T *dict = argvars[0].vval.v_dict;
-
-  if (argvars[0].v_type != VAR_DICT || dict == NULL) {
-    emsg(_(e_invarg));
-  } else {
-    dictitem_T *di;
-    if ((di = tv_dict_find(dict, S_LEN("lnum"))) != NULL) {
-      curwin->w_cursor.lnum = (linenr_T)tv_get_number(&di->di_tv);
-    }
-    if ((di = tv_dict_find(dict, S_LEN("col"))) != NULL) {
-      curwin->w_cursor.col = (colnr_T)tv_get_number(&di->di_tv);
-    }
-    if ((di = tv_dict_find(dict, S_LEN("coladd"))) != NULL) {
-      curwin->w_cursor.coladd = (colnr_T)tv_get_number(&di->di_tv);
-    }
-    if ((di = tv_dict_find(dict, S_LEN("curswant"))) != NULL) {
-      curwin->w_curswant = (colnr_T)tv_get_number(&di->di_tv);
-      curwin->w_set_curswant = false;
-    }
-    if ((di = tv_dict_find(dict, S_LEN("topline"))) != NULL) {
-      set_topline(curwin, (linenr_T)tv_get_number(&di->di_tv));
-    }
-    if ((di = tv_dict_find(dict, S_LEN("topfill"))) != NULL) {
-      curwin->w_topfill = (int)tv_get_number(&di->di_tv);
-    }
-    if ((di = tv_dict_find(dict, S_LEN("leftcol"))) != NULL) {
-      curwin->w_leftcol = (colnr_T)tv_get_number(&di->di_tv);
-    }
-    if ((di = tv_dict_find(dict, S_LEN("skipcol"))) != NULL) {
-      curwin->w_skipcol = (colnr_T)tv_get_number(&di->di_tv);
-    }
-
-    check_cursor();
-    win_new_height(curwin, curwin->w_height);
-    win_new_width(curwin, curwin->w_width);
-    changed_window_setting();
-
-    if (curwin->w_topline <= 0) {
-      curwin->w_topline = 1;
-    }
-    if (curwin->w_topline > curbuf->b_ml.ml_line_count) {
-      curwin->w_topline = curbuf->b_ml.ml_line_count;
-    }
-    check_topfill(curwin, true);
-  }
-}
-
-/// "winsaveview()" function
-static void f_winsaveview(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  tv_dict_alloc_ret(rettv);
-  dict_T *dict = rettv->vval.v_dict;
-
-  tv_dict_add_nr(dict, S_LEN("lnum"), (varnumber_T)curwin->w_cursor.lnum);
-  tv_dict_add_nr(dict, S_LEN("col"), (varnumber_T)curwin->w_cursor.col);
-  tv_dict_add_nr(dict, S_LEN("coladd"), (varnumber_T)curwin->w_cursor.coladd);
-  update_curswant();
-  tv_dict_add_nr(dict, S_LEN("curswant"), (varnumber_T)curwin->w_curswant);
-
-  tv_dict_add_nr(dict, S_LEN("topline"), (varnumber_T)curwin->w_topline);
-  tv_dict_add_nr(dict, S_LEN("topfill"), (varnumber_T)curwin->w_topfill);
-  tv_dict_add_nr(dict, S_LEN("leftcol"), (varnumber_T)curwin->w_leftcol);
-  tv_dict_add_nr(dict, S_LEN("skipcol"), (varnumber_T)curwin->w_skipcol);
-}
-
-/// "winwidth(nr)" function
-static void f_winwidth(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
-{
-  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
-  if (wp == NULL) {
-    rettv->vval.v_number = -1;
-  } else {
-    rettv->vval.v_number = wp->w_width_inner;
-  }
-}
-
 /// "windowsversion()" function
 static void f_windowsversion(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
@@ -9920,6 +9056,7 @@ static void f_writefile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   bool binary = false;
   bool append = false;
   bool do_fsync = !!p_fs;
+  bool mkdir_p = false;
   if (argvars[2].v_type != VAR_UNKNOWN) {
     const char *const flags = tv_get_string_chk(&argvars[2]);
     if (flags == NULL) {
@@ -9935,6 +9072,8 @@ static void f_writefile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
         do_fsync = true; break;
       case 'S':
         do_fsync = false; break;
+      case 'p':
+        mkdir_p = true; break;
       default:
         // Using %s, p and not %c, *p to preserve multibyte characters
         semsg(_("E5060: Unknown flag: %s"), p);
@@ -9954,6 +9093,7 @@ static void f_writefile(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     emsg(_("E482: Can't open file with an empty name"));
   } else if ((error = file_open(&fp, fname,
                                 ((append ? kFileAppend : kFileTruncate)
+                                 | (mkdir_p ? kFileMkDir : kFileCreate)
                                  | kFileCreate), 0666)) != 0) {
     semsg(_("E482: Can't open file %s for writing: %s"),
           fname, os_strerror(error));
diff --git a/src/nvim/eval/funcs.h b/src/nvim/eval/funcs.h
index adff0b2441..1ae031a952 100644
--- a/src/nvim/eval/funcs.h
+++ b/src/nvim/eval/funcs.h
@@ -1,9 +1,14 @@
 #ifndef NVIM_EVAL_FUNCS_H
 #define NVIM_EVAL_FUNCS_H
 
+#include <stdbool.h>
+#include <stdint.h>
+
 #include "nvim/api/private/dispatch.h"
 #include "nvim/buffer_defs.h"
 #include "nvim/eval/typval.h"
+#include "nvim/eval/typval_defs.h"
+#include "nvim/types.h"
 
 /// Prototype of C function that implements VimL function
 typedef void (*VimLFunc)(typval_T *args, typval_T *rvar, EvalFuncData data);
diff --git a/src/nvim/eval/gc.c b/src/nvim/eval/gc.c
index 633e6abacf..6a54c4ddc1 100644
--- a/src/nvim/eval/gc.c
+++ b/src/nvim/eval/gc.c
@@ -1,11 +1,12 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check
 // it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
+#include <stddef.h>
+
 #include "nvim/eval/gc.h"
-#include "nvim/eval/typval.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
-# include "eval/gc.c.generated.h"
+# include "eval/gc.c.generated.h"  // IWYU pragma: export
 #endif
 
 /// Head of list of all dictionaries
diff --git a/src/nvim/eval/gc.h b/src/nvim/eval/gc.h
index c2e862e469..3185750c3b 100644
--- a/src/nvim/eval/gc.h
+++ b/src/nvim/eval/gc.h
@@ -2,6 +2,7 @@
 #define NVIM_EVAL_GC_H
 
 #include "nvim/eval/typval.h"
+#include "nvim/eval/typval_defs.h"
 
 extern dict_T *gc_first_dict;
 extern list_T *gc_first_list;
diff --git a/src/nvim/eval/typval.c b/src/nvim/eval/typval.c
index a0b06aaaf4..05b4737206 100644
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -28,9 +28,9 @@
 #include "nvim/lua/executor.h"
 #include "nvim/macros.h"
 #include "nvim/mbyte.h"
+#include "nvim/mbyte_defs.h"
 #include "nvim/memory.h"
 #include "nvim/message.h"
-#include "nvim/os/fileio.h"
 #include "nvim/os/input.h"
 #include "nvim/pos.h"
 #include "nvim/types.h"
@@ -43,9 +43,11 @@
 static char e_string_required_for_argument_nr[]
   = N_("E1174: String required for argument %d");
 static char e_non_empty_string_required_for_argument_nr[]
-  = N_("E1142: Non-empty string required for argument %d");
+  = N_("E1175: Non-empty string required for argument %d");
 static char e_number_required_for_argument_nr[]
   = N_("E1210: Number required for argument %d");
+static char e_string_or_list_required_for_argument_nr[]
+  = N_("E1222: String or List required for argument %d");
 
 bool tv_in_free_unref_items = false;
 
@@ -324,10 +326,12 @@ void tv_list_free_list(list_T *const l)
 void tv_list_free(list_T *const l)
   FUNC_ATTR_NONNULL_ALL
 {
-  if (!tv_in_free_unref_items) {
-    tv_list_free_contents(l);
-    tv_list_free_list(l);
+  if (tv_in_free_unref_items) {
+    return;
   }
+
+  tv_list_free_contents(l);
+  tv_list_free_list(l);
 }
 
 /// Unreference a list
@@ -896,8 +900,8 @@ void tv_list_remove(typval_T *argvars, typval_T *rettv, const char *arg_errmsg)
   list_T *l;
   bool error = false;
 
-  if (var_check_lock(tv_list_locked((l = argvars[0].vval.v_list)),
-                     arg_errmsg, TV_TRANSLATE)) {
+  if (value_check_lock(tv_list_locked((l = argvars[0].vval.v_list)),
+                       arg_errmsg, TV_TRANSLATE)) {
     return;
   }
 
@@ -1094,7 +1098,9 @@ static int item_compare2(const void *s1, const void *s2, bool keep_zero)
   tv_clear(&argv[1]);
 
   if (res == FAIL) {
+    // XXX: ITEM_COMPARE_FAIL is unused
     res = ITEM_COMPARE_FAIL;
+    sortinfo->item_compare_func_err = true;
   } else {
     res = (int)tv_get_number_chk(&rettv, &sortinfo->item_compare_func_err);
     if (res > 0) {
@@ -1150,7 +1156,7 @@ static void do_sort_uniq(typval_T *argvars, typval_T *rettv, bool sort)
     semsg(_(e_listarg), sort ? "sort()" : "uniq()");
   } else {
     list_T *const l = argvars[0].vval.v_list;
-    if (var_check_lock(tv_list_locked(l), arg_errmsg, TV_TRANSLATE)) {
+    if (value_check_lock(tv_list_locked(l), arg_errmsg, TV_TRANSLATE)) {
       goto theend;
     }
     tv_list_set_ret(rettv, l);
@@ -1257,7 +1263,7 @@ static void do_sort_uniq(typval_T *argvars, typval_T *rettv, bool sort)
         } else {
           li = TV_LIST_ITEM_NEXT(l, li);
         }
-        if (info.item_compare_func_err) {  // -V547
+        if (info.item_compare_func_err) {
           emsg(_("E882: Uniq compare function failed"));
           break;
         }
@@ -1361,7 +1367,7 @@ void tv_list_reverse(list_T *const l)
 ///               true list will not be modified. Must be initialized to false
 ///               by the caller.
 void tv_list_item_sort(list_T *const l, ListSortItem *const ptrs,
-                       const ListSorter item_compare_func, bool *errp)
+                       const ListSorter item_compare_func, const bool *errp)
   FUNC_ATTR_NONNULL_ARG(3, 4)
 {
   const int len = tv_list_len(l);
@@ -1593,7 +1599,7 @@ void callback_free(Callback *callback)
 {
   switch (callback->type) {
   case kCallbackFuncref:
-    func_unref((char_u *)callback->data.funcref);
+    func_unref(callback->data.funcref);
     xfree(callback->data.funcref);
     break;
   case kCallbackPartial:
@@ -1622,7 +1628,7 @@ void callback_put(Callback *cb, typval_T *tv)
   case kCallbackFuncref:
     tv->v_type = VAR_FUNC;
     tv->vval.v_string = xstrdup(cb->data.funcref);
-    func_ref((char_u *)cb->data.funcref);
+    func_ref(cb->data.funcref);
     break;
   case kCallbackLua:
   // TODO(tjdevries): Unified Callback.
@@ -1648,7 +1654,7 @@ void callback_copy(Callback *dest, Callback *src)
     break;
   case kCallbackFuncref:
     dest->data.funcref = xstrdup(src->data.funcref);
-    func_ref((char_u *)src->data.funcref);
+    func_ref(src->data.funcref);
     break;
   case kCallbackLua:
     dest->data.luaref = api_new_luaref(src->data.luaref);
@@ -1745,9 +1751,8 @@ static bool tv_dict_watcher_matches(DictWatcher *watcher, const char *const key)
   const size_t len = watcher->key_pattern_len;
   if (len && watcher->key_pattern[len - 1] == '*') {
     return strncmp(key, watcher->key_pattern, len - 1) == 0;
-  } else {
-    return strcmp(key, watcher->key_pattern) == 0;
   }
+  return strcmp(key, watcher->key_pattern) == 0;
 }
 
 /// Send a change notification to all dictionary watchers that match given key
@@ -1839,6 +1844,7 @@ dictitem_T *tv_dict_item_alloc_len(const char *const key, const size_t key_len)
   di->di_key[key_len] = NUL;
   di->di_flags = DI_FLAGS_ALLOC;
   di->di_tv.v_lock = VAR_UNLOCKED;
+  di->di_tv.v_type = VAR_UNKNOWN;
   return di;
 }
 
@@ -2058,9 +2064,24 @@ int tv_dict_get_tv(dict_T *d, const char *const key, typval_T *rettv)
 varnumber_T tv_dict_get_number(const dict_T *const d, const char *const key)
   FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
 {
+  return tv_dict_get_number_def(d, key, 0);
+}
+
+/// Get a number item from a dictionary.
+///
+/// Returns "def" if the entry doesn't exist.
+///
+/// @param[in]  d  Dictionary to get item from.
+/// @param[in]  key  Key to find in dictionary.
+/// @param[in]  def  Default value.
+///
+/// @return Dictionary item.
+varnumber_T tv_dict_get_number_def(const dict_T *const d, const char *const key, const int def)
+  FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
+{
   dictitem_T *const di = tv_dict_find(d, key, -1);
   if (di == NULL) {
-    return 0;
+    return def;
   }
   return tv_get_number(&di->di_tv);
 }
@@ -2079,7 +2100,7 @@ char **tv_dict_to_env(dict_T *denv)
   TV_DICT_ITER(denv, var, {
     const char *str = tv_get_string(&var->di_tv);
     assert(str);
-    size_t len = STRLEN(var->di_key) + strlen(str) + strlen("=") + 1;
+    size_t len = strlen((char *)var->di_key) + strlen(str) + strlen("=") + 1;
     env[i] = xmalloc(len);
     snprintf(env[i], len, "%s=%s", (char *)var->di_key, str);
     i++;
@@ -2188,6 +2209,15 @@ bool tv_dict_get_callback(dict_T *const d, const char *const key, const ptrdiff_
   return res;
 }
 
+/// Check for adding a function to g: or l:.
+/// If the name is wrong give an error message and return true.
+int tv_dict_wrong_func_name(dict_T *d, typval_T *tv, const char *name)
+{
+  return (d == &globvardict || &d->dv_hashtab == get_funccal_local_ht())
+         && tv_is_func(*tv)
+         && var_wrong_func_name(name, true);
+}
+
 //{{{2 dict_add*
 
 /// Add item to dictionary
@@ -2199,7 +2229,10 @@ bool tv_dict_get_callback(dict_T *const d, const char *const key, const ptrdiff_
 int tv_dict_add(dict_T *const d, dictitem_T *const item)
   FUNC_ATTR_NONNULL_ALL
 {
-  return hash_add(&d->dv_hashtab, item->di_key);
+  if (tv_dict_wrong_func_name(d, &item->di_tv, (const char *)item->di_key)) {
+    return FAIL;
+  }
+  return hash_add(&d->dv_hashtab, (char *)item->di_key);
 }
 
 /// Add a list entry to dictionary
@@ -2415,10 +2448,10 @@ void tv_dict_clear(dict_T *const d)
 ///
 /// @param  d1  Dictionary to extend.
 /// @param[in]  d2  Dictionary to extend with.
-/// @param[in]  action  "error", "force", "keep":
-///
+/// @param[in]  action  "error", "force", "move", "keep":
 ///                     e*, including "error": duplicate key gives an error.
 ///                     f*, including "force": duplicate d2 keys override d1.
+///                     m*, including "move": move items instead of copying.
 ///                     other, including "keep": duplicate d2 keys ignored.
 void tv_dict_extend(dict_T *const d1, dict_T *const d2, const char *const action)
   FUNC_ATTR_NONNULL_ALL
@@ -2427,27 +2460,33 @@ void tv_dict_extend(dict_T *const d1, dict_T *const d2, const char *const action
   const char *const arg_errmsg = _("extend() argument");
   const size_t arg_errmsg_len = strlen(arg_errmsg);
 
-  TV_DICT_ITER(d2, di2, {
+  if (*action == 'm') {
+    hash_lock(&d2->dv_hashtab);  // don't rehash on hash_remove()
+  }
+
+  HASHTAB_ITER(&d2->dv_hashtab, hi2, {
+    dictitem_T *const di2 = TV_DICT_HI2DI(hi2);
     dictitem_T *const di1 = tv_dict_find(d1, (const char *)di2->di_key, -1);
-    if (d1->dv_scope != VAR_NO_SCOPE) {
-      // Disallow replacing a builtin function in l: and g:.
-      // Check the key to be valid when adding to any scope.
-      if (d1->dv_scope == VAR_DEF_SCOPE
-          && tv_is_func(di2->di_tv)
-          && !var_check_func_name((const char *)di2->di_key, di1 == NULL)) {
-        break;
-      }
-      if (!valid_varname((const char *)di2->di_key)) {
-        break;
-      }
+    // Check the key to be valid when adding to any scope.
+    if (d1->dv_scope != VAR_NO_SCOPE && !valid_varname((const char *)di2->di_key)) {
+      break;
     }
     if (di1 == NULL) {
-      dictitem_T *const new_di = tv_dict_item_copy(di2);
-      if (tv_dict_add(d1, new_di) == FAIL) {
-        tv_dict_item_free(new_di);
-      } else if (watched) {
-        tv_dict_watcher_notify(d1, (const char *)new_di->di_key, &new_di->di_tv,
-                               NULL);
+      if (*action == 'm') {
+        // Cheap way to move a dict item from "d2" to "d1".
+        // If dict_add() fails then "d2" won't be empty.
+        dictitem_T *const new_di = di2;
+        if (tv_dict_add(d1, new_di) == OK) {
+          hash_remove(&d2->dv_hashtab, hi2);
+          tv_dict_watcher_notify(d1, (const char *)new_di->di_key, &new_di->di_tv, NULL);
+        }
+      } else {
+        dictitem_T *const new_di = tv_dict_item_copy(di2);
+        if (tv_dict_add(d1, new_di) == FAIL) {
+          tv_dict_item_free(new_di);
+        } else if (watched) {
+          tv_dict_watcher_notify(d1, (const char *)new_di->di_key, &new_di->di_tv, NULL);
+        }
       }
     } else if (*action == 'e') {
       semsg(_("E737: Key already exists: %s"), di2->di_key);
@@ -2455,10 +2494,14 @@ void tv_dict_extend(dict_T *const d1, dict_T *const d2, const char *const action
     } else if (*action == 'f' && di2 != di1) {
       typval_T oldtv;
 
-      if (var_check_lock(di1->di_tv.v_lock, arg_errmsg, arg_errmsg_len)
+      if (value_check_lock(di1->di_tv.v_lock, arg_errmsg, arg_errmsg_len)
           || var_check_ro(di1->di_flags, arg_errmsg, arg_errmsg_len)) {
         break;
       }
+      // Disallow replacing a builtin function.
+      if (tv_dict_wrong_func_name(d1, &di2->di_tv, (const char *)di2->di_key)) {
+        break;
+      }
 
       if (watched) {
         tv_copy(&di1->di_tv, &oldtv);
@@ -2474,6 +2517,10 @@ void tv_dict_extend(dict_T *const d1, dict_T *const d2, const char *const action
       }
     }
   });
+
+  if (*action == 'm') {
+    hash_unlock(&d2->dv_hashtab);
+  }
 }
 
 /// Compare two dictionaries
@@ -2488,10 +2535,14 @@ bool tv_dict_equal(dict_T *const d1, dict_T *const d2, const bool ic, const bool
   if (d1 == d2) {
     return true;
   }
-  if (d1 == NULL || d2 == NULL) {
+  if (tv_dict_len(d1) != tv_dict_len(d2)) {
     return false;
   }
-  if (tv_dict_len(d1) != tv_dict_len(d2)) {
+  if (tv_dict_len(d1) == 0) {
+    // empty and NULL dicts are considered equal
+    return true;
+  }
+  if (d1 == NULL || d2 == NULL) {
     return false;
   }
 
@@ -2537,7 +2588,7 @@ dict_T *tv_dict_copy(const vimconv_T *const conv, dict_T *const orig, const bool
     if (conv == NULL || conv->vc_type == CONV_NONE) {
       new_di = tv_dict_item_alloc((const char *)di->di_key);
     } else {
-      size_t len = STRLEN(di->di_key);
+      size_t len = strlen((char *)di->di_key);
       char *const key = (char *)string_convert(conv, (char *)di->di_key, &len);
       if (key == NULL) {
         new_di = tv_dict_item_alloc_len((const char *)di->di_key, len);
@@ -2659,7 +2710,7 @@ void tv_blob_remove(typval_T *argvars, typval_T *rettv, const char *arg_errmsg)
 {
   blob_T *const b = argvars[0].vval.v_blob;
 
-  if (b != NULL && var_check_lock(b->bv_lock, arg_errmsg, TV_TRANSLATE)) {
+  if (b != NULL && value_check_lock(b->bv_lock, arg_errmsg, TV_TRANSLATE)) {
     return;
   }
 
@@ -2679,7 +2730,7 @@ void tv_blob_remove(typval_T *argvars, typval_T *rettv, const char *arg_errmsg)
     }
     if (argvars[2].v_type == VAR_UNKNOWN) {
       // Remove one item, return its value.
-      char_u *const p = (char_u *)b->bv_ga.ga_data;
+      uint8_t *const p = (uint8_t *)b->bv_ga.ga_data;
       rettv->vval.v_number = (varnumber_T)(*(p + idx));
       memmove(p + idx, p + idx + 1, (size_t)(len - idx - 1));
       b->bv_ga.ga_len--;
@@ -2701,9 +2752,8 @@ void tv_blob_remove(typval_T *argvars, typval_T *rettv, const char *arg_errmsg)
       blob->bv_ga.ga_len = (int)(end - idx + 1);
       ga_grow(&blob->bv_ga, (int)(end - idx + 1));
 
-      char_u *const p = (char_u *)b->bv_ga.ga_data;
-      memmove((char_u *)blob->bv_ga.ga_data, p + idx,
-              (size_t)(end - idx + 1));
+      uint8_t *const p = (uint8_t *)b->bv_ga.ga_data;
+      memmove(blob->bv_ga.ga_data, p + idx, (size_t)(end - idx + 1));
       tv_blob_set_ret(rettv, blob);
 
       if (len - end - 1 > 0) {
@@ -2851,7 +2901,7 @@ void tv_dict_remove(typval_T *argvars, typval_T *rettv, const char *arg_errmsg)
   if (argvars[2].v_type != VAR_UNKNOWN) {
     semsg(_(e_toomanyarg), "remove()");
   } else if ((d = argvars[0].vval.v_dict) != NULL
-             && !var_check_lock(d->dv_lock, arg_errmsg, TV_TRANSLATE)) {
+             && !value_check_lock(d->dv_lock, arg_errmsg, TV_TRANSLATE)) {
     const char *key = tv_get_string_chk(&argvars[1]);
     if (key != NULL) {
       dictitem_T *di = tv_dict_find(d, key, -1);
@@ -2956,7 +3006,7 @@ void tv_blob_copy(typval_T *const from, typval_T *const to)
     (tv)->v_lock = VAR_UNLOCKED; \
   } while (0)
 
-static inline int _nothing_conv_func_start(typval_T *const tv, char_u *const fun)
+static inline int _nothing_conv_func_start(typval_T *const tv, char *const fun)
   FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_ALWAYS_INLINE FUNC_ATTR_NONNULL_ARG(1)
 {
   tv->v_lock = VAR_UNLOCKED;
@@ -3119,6 +3169,7 @@ static inline void _nothing_conv_dict_end(typval_T *const tv, dict_T **const dic
 #define TYPVAL_ENCODE_FIRST_ARG_TYPE const void *const
 #define TYPVAL_ENCODE_FIRST_ARG_NAME ignored
 #include "nvim/eval/typval_encode.c.h"
+
 #undef TYPVAL_ENCODE_SCOPE
 #undef TYPVAL_ENCODE_NAME
 #undef TYPVAL_ENCODE_FIRST_ARG_TYPE
@@ -3183,7 +3234,7 @@ void tv_free(typval_T *tv)
       partial_unref(tv->vval.v_partial);
       break;
     case VAR_FUNC:
-      func_unref((char_u *)tv->vval.v_string);
+      func_unref(tv->vval.v_string);
       FALLTHROUGH;
     case VAR_STRING:
       xfree(tv->vval.v_string);
@@ -3236,7 +3287,7 @@ void tv_copy(const typval_T *const from, typval_T *const to)
     if (from->vval.v_string != NULL) {
       to->vval.v_string = xstrdup(from->vval.v_string);
       if (from->v_type == VAR_FUNC) {
-        func_ref((char_u *)to->vval.v_string);
+        func_ref(to->vval.v_string);
       }
     }
     break;
@@ -3408,12 +3459,12 @@ bool tv_check_lock(const typval_T *tv, const char *name, size_t name_len)
   default:
     break;
   }
-  return var_check_lock(tv->v_lock, name, name_len)
-         || (lock != VAR_UNLOCKED && var_check_lock(lock, name, name_len));
+  return value_check_lock(tv->v_lock, name, name_len)
+         || (lock != VAR_UNLOCKED && value_check_lock(lock, name, name_len));
 }
 
-/// @return true if variable "name" is locked (immutable)
-bool var_check_lock(VarLockStatus lock, const char *name, size_t name_len)
+/// @return true if variable "name" has a locked (immutable) value
+bool value_check_lock(VarLockStatus lock, const char *name, size_t name_len)
 {
   const char *error_message = NULL;
   switch (lock) {
@@ -3588,13 +3639,13 @@ bool tv_check_str_or_nr(const typval_T *const tv)
 #define FUNC_ERROR "E703: Using a Funcref as a Number"
 
 static const char *const num_errors[] = {
-  [VAR_PARTIAL]=N_(FUNC_ERROR),
-  [VAR_FUNC]=N_(FUNC_ERROR),
-  [VAR_LIST]=N_("E745: Using a List as a Number"),
-  [VAR_DICT]=N_("E728: Using a Dictionary as a Number"),
-  [VAR_FLOAT]=N_("E805: Using a Float as a Number"),
-  [VAR_BLOB]=N_("E974: Using a Blob as a Number"),
-  [VAR_UNKNOWN]=N_("E685: using an invalid value as a Number"),
+  [VAR_PARTIAL]= N_(FUNC_ERROR),
+  [VAR_FUNC]= N_(FUNC_ERROR),
+  [VAR_LIST]= N_("E745: Using a List as a Number"),
+  [VAR_DICT]= N_("E728: Using a Dictionary as a Number"),
+  [VAR_FLOAT]= N_("E805: Using a Float as a Number"),
+  [VAR_BLOB]= N_("E974: Using a Blob as a Number"),
+  [VAR_UNKNOWN]= N_("E685: using an invalid value as a Number"),
 };
 
 #undef FUNC_ERROR
@@ -3633,13 +3684,13 @@ bool tv_check_num(const typval_T *const tv)
 #define FUNC_ERROR "E729: using Funcref as a String"
 
 static const char *const str_errors[] = {
-  [VAR_PARTIAL]=N_(FUNC_ERROR),
-  [VAR_FUNC]=N_(FUNC_ERROR),
-  [VAR_LIST]=N_("E730: using List as a String"),
-  [VAR_DICT]=N_("E731: using Dictionary as a String"),
-  [VAR_FLOAT]=((const char *)e_float_as_string),
-  [VAR_BLOB]=N_("E976: using Blob as a String"),
-  [VAR_UNKNOWN]=N_("E908: using an invalid value as a String"),
+  [VAR_PARTIAL]= N_(FUNC_ERROR),
+  [VAR_FUNC]= N_(FUNC_ERROR),
+  [VAR_LIST]= N_("E730: using List as a String"),
+  [VAR_DICT]= N_("E731: using Dictionary as a String"),
+  [VAR_FLOAT]= ((const char *)e_float_as_string),
+  [VAR_BLOB]= N_("E976: using Blob as a String"),
+  [VAR_UNKNOWN]= N_("E908: using an invalid value as a String"),
 };
 
 #undef FUNC_ERROR
@@ -3851,6 +3902,17 @@ int tv_check_for_opt_number_arg(const typval_T *const args, const int idx)
           || tv_check_for_number_arg(args, idx) != FAIL) ? OK : FAIL;
 }
 
+/// Give an error and return FAIL unless "args[idx]" is a string or a list.
+int tv_check_for_string_or_list_arg(const typval_T *const args, const int idx)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_PURE
+{
+  if (args[idx].v_type != VAR_STRING && args[idx].v_type != VAR_LIST) {
+    semsg(_(e_string_or_list_required_for_argument_nr), idx + 1);
+    return FAIL;
+  }
+  return OK;
+}
+
 /// Get the string value of a "stringish" VimL object.
 ///
 /// @param[in]  tv  Object to get value of.
diff --git a/src/nvim/eval/typval.h b/src/nvim/eval/typval.h
index 0a4adc1f53..3f59cd3547 100644
--- a/src/nvim/eval/typval.h
+++ b/src/nvim/eval/typval.h
@@ -4,14 +4,19 @@
 #include <assert.h>
 #include <stdbool.h>
 #include <stddef.h>
+#include <stdint.h>
 #include <string.h>
 
 #include "nvim/eval/typval_defs.h"
 #include "nvim/func_attr.h"
+#include "nvim/garray.h"
 #include "nvim/gettext.h"
+#include "nvim/hashtab.h"
+#include "nvim/lib/queue.h"
 #include "nvim/macros.h"
 #include "nvim/mbyte_defs.h"
 #include "nvim/message.h"
+#include "nvim/types.h"
 
 #ifdef LOG_LIST_ACTIONS
 # include "nvim/memory.h"
@@ -43,10 +48,8 @@ static inline ListLog *list_log_new(const size_t size)
   return ret;
 }
 
-static inline void list_log(const list_T *const l,
-                            const listitem_T *const li1,
-                            const listitem_T *const li2,
-                            const char *const action)
+static inline void list_log(const list_T *const l, const listitem_T *const li1,
+                            const listitem_T *const li2, const char *const action)
   REAL_FATTR_ALWAYS_INLINE;
 
 /// Add new entry to log
@@ -90,7 +93,7 @@ static inline void list_log(const list_T *const l, const listitem_T *const li1,
 #define TV_DICT_HI2DI(hi) \
   ((dictitem_T *)((hi)->hi_key - offsetof(dictitem_T, di_key)))
 
-static inline void tv_list_ref(list_T *const l)
+static inline void tv_list_ref(list_T *l)
   REAL_FATTR_ALWAYS_INLINE;
 
 /// Increase reference count for a given list
@@ -106,7 +109,7 @@ static inline void tv_list_ref(list_T *const l)
   l->lv_refcount++;
 }
 
-static inline void tv_list_set_ret(typval_T *const tv, list_T *const l)
+static inline void tv_list_set_ret(typval_T *tv, list_T *l)
   REAL_FATTR_ALWAYS_INLINE REAL_FATTR_NONNULL_ARG(1);
 
 /// Set a list as the return value.  Increments the reference count.
@@ -120,7 +123,7 @@ static inline void tv_list_set_ret(typval_T *const tv, list_T *const l)
   tv_list_ref(l);
 }
 
-static inline VarLockStatus tv_list_locked(const list_T *const l)
+static inline VarLockStatus tv_list_locked(const list_T *l)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Get list lock status
@@ -163,7 +166,7 @@ static inline void tv_list_set_copyid(list_T *const l, const int copyid)
   l->lv_copyID = copyid;
 }
 
-static inline int tv_list_len(const list_T *const l)
+static inline int tv_list_len(const list_T *l)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Get the number of items in a list
@@ -178,7 +181,7 @@ static inline int tv_list_len(const list_T *const l)
   return l->lv_len;
 }
 
-static inline int tv_list_copyid(const list_T *const l)
+static inline int tv_list_copyid(const list_T *l)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT REAL_FATTR_NONNULL_ALL;
 
 /// Get list copyID
@@ -191,7 +194,7 @@ static inline int tv_list_copyid(const list_T *const l)
   return l->lv_copyID;
 }
 
-static inline list_T *tv_list_latest_copy(const list_T *const l)
+static inline list_T *tv_list_latest_copy(const list_T *l)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT REAL_FATTR_NONNULL_ALL;
 
 /// Get latest list copy
@@ -206,7 +209,7 @@ static inline list_T *tv_list_latest_copy(const list_T *const l)
   return l->lv_copylist;
 }
 
-static inline int tv_list_uidx(const list_T *const l, int n)
+static inline int tv_list_uidx(const list_T *l, int n)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Normalize index: that is, return either -1 or non-negative index
@@ -229,7 +232,7 @@ static inline int tv_list_uidx(const list_T *const l, int n)
   return n;
 }
 
-static inline bool tv_list_has_watchers(const list_T *const l)
+static inline bool tv_list_has_watchers(const list_T *l)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Check whether list has watchers
@@ -244,7 +247,7 @@ static inline bool tv_list_has_watchers(const list_T *const l)
   return l && l->lv_watch;
 }
 
-static inline listitem_T *tv_list_first(const list_T *const l)
+static inline listitem_T *tv_list_first(const list_T *l)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Get first list item
@@ -262,7 +265,7 @@ static inline listitem_T *tv_list_first(const list_T *const l)
   return l->lv_first;
 }
 
-static inline listitem_T *tv_list_last(const list_T *const l)
+static inline listitem_T *tv_list_last(const list_T *l)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Get last list item
@@ -280,7 +283,7 @@ static inline listitem_T *tv_list_last(const list_T *const l)
   return l->lv_last;
 }
 
-static inline void tv_dict_set_ret(typval_T *const tv, dict_T *const d)
+static inline void tv_dict_set_ret(typval_T *tv, dict_T *d)
   REAL_FATTR_ALWAYS_INLINE REAL_FATTR_NONNULL_ARG(1);
 
 /// Set a dictionary as the return value
@@ -296,7 +299,7 @@ static inline void tv_dict_set_ret(typval_T *const tv, dict_T *const d)
   }
 }
 
-static inline long tv_dict_len(const dict_T *const d)
+static inline long tv_dict_len(const dict_T *d)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Get the number of items in a Dictionary
@@ -310,7 +313,7 @@ static inline long tv_dict_len(const dict_T *const d)
   return (long)d->dv_hashtab.ht_used;
 }
 
-static inline bool tv_dict_is_watched(const dict_T *const d)
+static inline bool tv_dict_is_watched(const dict_T *d)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Check if dictionary is watched
@@ -323,7 +326,7 @@ static inline bool tv_dict_is_watched(const dict_T *const d)
   return d && !QUEUE_EMPTY(&d->watchers);
 }
 
-static inline void tv_blob_set_ret(typval_T *const tv, blob_T *const b)
+static inline void tv_blob_set_ret(typval_T *tv, blob_T *b)
   REAL_FATTR_ALWAYS_INLINE REAL_FATTR_NONNULL_ARG(1);
 
 /// Set a blob as the return value.
@@ -341,7 +344,7 @@ static inline void tv_blob_set_ret(typval_T *const tv, blob_T *const b)
   }
 }
 
-static inline int tv_blob_len(const blob_T *const b)
+static inline int tv_blob_len(const blob_T *b)
   REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Get the length of the data in the blob, in bytes.
@@ -355,7 +358,7 @@ static inline int tv_blob_len(const blob_T *const b)
   return b->bv_ga.ga_len;
 }
 
-static inline char_u tv_blob_get(const blob_T *const b, int idx)
+static inline uint8_t tv_blob_get(const blob_T *b, int idx)
   REAL_FATTR_ALWAYS_INLINE REAL_FATTR_NONNULL_ALL REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Get the byte at index `idx` in the blob.
@@ -364,12 +367,12 @@ static inline char_u tv_blob_get(const blob_T *const b, int idx)
 /// @param[in]  idx  Index in a blob. Must be valid.
 ///
 /// @return Byte value at the given index.
-static inline char_u tv_blob_get(const blob_T *const b, int idx)
+static inline uint8_t tv_blob_get(const blob_T *const b, int idx)
 {
-  return ((char_u *)b->bv_ga.ga_data)[idx];
+  return ((uint8_t *)b->bv_ga.ga_data)[idx];
 }
 
-static inline void tv_blob_set(blob_T *const b, int idx, char_u c)
+static inline void tv_blob_set(blob_T *b, int idx, uint8_t c)
   REAL_FATTR_ALWAYS_INLINE REAL_FATTR_NONNULL_ALL;
 
 /// Store the byte `c` at index `idx` in the blob.
@@ -377,9 +380,9 @@ static inline void tv_blob_set(blob_T *const b, int idx, char_u c)
 /// @param[in]  b  Blob to index. Cannot be NULL.
 /// @param[in]  idx  Index in a blob. Must be valid.
 /// @param[in]  c  Value to store.
-static inline void tv_blob_set(blob_T *const b, int idx, char_u c)
+static inline void tv_blob_set(blob_T *const b, int idx, uint8_t c)
 {
-  ((char_u *)b->bv_ga.ga_data)[idx] = c;
+  ((uint8_t *)b->bv_ga.ga_data)[idx] = c;
 }
 
 /// Initialize VimL object
@@ -431,7 +434,7 @@ extern bool tv_in_free_unref_items;
 /// @param  li  Name of the variable with current listitem_T entry.
 /// @param  code  Cycle body.
 #define TV_LIST_ITER(l, li, code) \
-  _TV_LIST_ITER_MOD( , l, li, code)
+  _TV_LIST_ITER_MOD( , l, li, code)  // NOLINT(whitespace/parens)
 
 /// Iterate over a list
 ///
@@ -488,8 +491,7 @@ extern bool tv_in_free_unref_items;
     } \
   })
 
-static inline bool tv_get_float_chk(const typval_T *const tv,
-                                    float_T *const ret_f)
+static inline bool tv_get_float_chk(const typval_T *tv, float_T *ret_f)
   REAL_FATTR_NONNULL_ALL REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Get the float value
@@ -527,7 +529,7 @@ static inline DictWatcher *tv_dict_watcher_node_data(QUEUE *q)
   return QUEUE_DATA(q, DictWatcher, node);
 }
 
-static inline bool tv_is_func(const typval_T tv)
+static inline bool tv_is_func(typval_T tv)
   FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_ALWAYS_INLINE FUNC_ATTR_CONST;
 
 /// Check whether given typval_T contains a function
@@ -562,4 +564,9 @@ EXTERN const size_t kTVTranslate INIT(= TV_TRANSLATE);
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "eval/typval.h.generated.h"
 #endif
+
+#define tv_get_bool tv_get_number
+#define tv_get_bool_chk tv_get_number_chk
+#define tv_dict_get_bool tv_dict_get_number_def
+
 #endif  // NVIM_EVAL_TYPVAL_H
diff --git a/src/nvim/eval/typval_defs.h b/src/nvim/eval/typval_defs.h
index 1c0a438751..4615198441 100644
--- a/src/nvim/eval/typval_defs.h
+++ b/src/nvim/eval/typval_defs.h
@@ -206,7 +206,7 @@ typedef struct {
   struct { \
     typval_T di_tv;  /* Structure that holds scope dictionary itself. */ \
     uint8_t di_flags;  /* Flags. */ \
-    char_u di_key[__VA_ARGS__];  /* Key value. */ \
+    char_u di_key[__VA_ARGS__];  /* Key value. */  /* NOLINT(runtime/arrays)*/ \
   }
 
 /// Structure to hold a scope dictionary
@@ -337,9 +337,9 @@ struct ufunc {
                            ///< used for s: variables
   int uf_refcount;      ///< reference count, see func_name_refcount()
   funccall_T *uf_scoped;       ///< l: local variables for closure
-  char_u *uf_name_exp;  ///< if "uf_name[]" starts with SNR the name with
+  char *uf_name_exp;    ///< if "uf_name[]" starts with SNR the name with
                         ///< "<SNR>" as a string, otherwise NULL
-  char_u uf_name[];  ///< Name of function (actual size equals name);
+  char uf_name[];    ///< Name of function (actual size equals name);
                      ///< can start with <SNR>123_
                      ///< (<SNR> is K_SPECIAL KS_EXTRA KE_SNR)
 };
diff --git a/src/nvim/eval/typval_encode.c.h b/src/nvim/eval/typval_encode.c.h
index ff4f92e40b..6d29286a58 100644
--- a/src/nvim/eval/typval_encode.c.h
+++ b/src/nvim/eval/typval_encode.c.h
@@ -266,7 +266,7 @@ static inline int _TYPVAL_ENCODE_CHECK_SELF_REFERENCE(
                                                       const MPConvStack *const mpstack, const int copyID,
                                                       const MPConvStackValType conv_type,
                                                       const char *const objname)
-REAL_FATTR_NONNULL_ARG(2, 3, 4, 7) REAL_FATTR_WARN_UNUSED_RESULT
+  REAL_FATTR_NONNULL_ARG(2, 3, 4, 7) REAL_FATTR_WARN_UNUSED_RESULT
   REAL_FATTR_ALWAYS_INLINE;
 
 /// Function for checking whether container references itself
@@ -301,7 +301,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
                                             MPConvStack *const mpstack, MPConvStackVal *const cur_mpsv,
                                             typval_T *const tv, const int copyID,
                                             const char *const objname)
-REAL_FATTR_NONNULL_ARG(2, 4, 6) REAL_FATTR_WARN_UNUSED_RESULT;
+  REAL_FATTR_NONNULL_ARG(2, 4, 6) REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Convert single value
 ///
@@ -339,7 +339,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
                             tv_blob_len(tv->vval.v_blob));
     break;
   case VAR_FUNC:
-    TYPVAL_ENCODE_CONV_FUNC_START(tv, (char_u *)tv->vval.v_string);
+    TYPVAL_ENCODE_CONV_FUNC_START(tv, tv->vval.v_string);
     TYPVAL_ENCODE_CONV_FUNC_BEFORE_ARGS(tv, 0);
     TYPVAL_ENCODE_CONV_FUNC_BEFORE_SELF(tv, -1);
     TYPVAL_ENCODE_CONV_FUNC_END(tv);
@@ -347,7 +347,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
   case VAR_PARTIAL: {
     partial_T *const pt = tv->vval.v_partial;
     (void)pt;
-    TYPVAL_ENCODE_CONV_FUNC_START(tv, (pt == NULL ? NULL : (char_u *)partial_name(pt)));  // -V547
+    TYPVAL_ENCODE_CONV_FUNC_START(tv, (pt == NULL ? NULL : partial_name(pt)));  // -V547
     _mp_push(*mpstack, ((MPConvStackVal) {  // -V779
         .type = kMPConvPartial,
         .tv = tv,
@@ -358,7 +358,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
             .pt = tv->vval.v_partial,
           },
         },
-      }));
+    }));
     break;
   }
   case VAR_LIST: {
@@ -381,7 +381,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
             .li = tv_list_first(tv->vval.v_list),
           },
         },
-      }));
+    }));
     TYPVAL_ENCODE_CONV_REAL_LIST_AFTER_START(tv, _mp_last(*mpstack));
     break;
   }
@@ -459,8 +459,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
         const listitem_T *const highest_bits_li = (
                                                    TV_LIST_ITEM_NEXT(val_list, sign_li));
         if (TV_LIST_ITEM_TV(highest_bits_li)->v_type != VAR_NUMBER
-            || ((highest_bits
-                   = TV_LIST_ITEM_TV(highest_bits_li)->vval.v_number)
+            || ((highest_bits = TV_LIST_ITEM_TV(highest_bits_li)->vval.v_number)
                 < 0)) {
           goto _convert_one_value_regular_dict;
         }
@@ -536,7 +535,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
                   .li = tv_list_first(val_di->di_tv.vval.v_list),
                 },
               },
-            }));
+        }));
         break;
       }
       case kMPMap: {
@@ -571,7 +570,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
                   .li = tv_list_first(val_list),
                 },
               },
-            }));
+        }));
         break;
       }
       case kMPExt: {
@@ -581,8 +580,7 @@ static int _TYPVAL_ENCODE_CONVERT_ONE_VALUE(
             || tv_list_len((val_list = val_di->di_tv.vval.v_list)) != 2
             || (TV_LIST_ITEM_TV(tv_list_first(val_list))->v_type
                 != VAR_NUMBER)
-            || ((type
-                   = TV_LIST_ITEM_TV(tv_list_first(val_list))->vval.v_number)
+            || ((type = TV_LIST_ITEM_TV(tv_list_first(val_list))->vval.v_number)
                 > INT8_MAX)
             || type < INT8_MIN
             || (TV_LIST_ITEM_TV(tv_list_last(val_list))->v_type
@@ -622,7 +620,7 @@ _convert_one_value_regular_dict: {}
             .todo = tv->vval.v_dict->dv_hashtab.ht_used,
           },
         },
-      }));
+    }));
     TYPVAL_ENCODE_CONV_REAL_DICT_AFTER_START(tv, tv->vval.v_dict,
                                              _mp_last(*mpstack));
     break;
@@ -640,7 +638,7 @@ typval_encode_stop_converting_one_item:
 TYPVAL_ENCODE_SCOPE int _TYPVAL_ENCODE_ENCODE(
                                               TYPVAL_ENCODE_FIRST_ARG_TYPE TYPVAL_ENCODE_FIRST_ARG_NAME,
                                               typval_T *const tv, const char *const objname)
-REAL_FATTR_NONNULL_ARG(2, 3) REAL_FATTR_WARN_UNUSED_RESULT;
+  REAL_FATTR_NONNULL_ARG(2, 3) REAL_FATTR_WARN_UNUSED_RESULT;
 
 /// Convert the whole typval
 ///
@@ -758,7 +756,7 @@ typval_encode_stop_converting_one_item:
                   .todo = (size_t)pt->pt_argc,
                 },
               },
-            }));
+          }));
         }
         break;
       case kMPConvPartialSelf: {
@@ -797,7 +795,7 @@ typval_encode_stop_converting_one_item:
                     .todo = dict->dv_hashtab.ht_used,
                   },
                 },
-              }));
+          }));
           TYPVAL_ENCODE_CONV_REAL_DICT_AFTER_START(NULL, pt->pt_dict,
                                                    _mp_last(mpstack));
         } else {
diff --git a/src/nvim/eval/typval_encode.h b/src/nvim/eval/typval_encode.h
index 33e19c531c..2f19144da3 100644
--- a/src/nvim/eval/typval_encode.h
+++ b/src/nvim/eval/typval_encode.h
@@ -71,7 +71,7 @@ typedef kvec_withinit_t(MPConvStackVal, 8) MPConvStack;
 #define _mp_pop kv_pop
 #define _mp_last kv_last
 
-static inline size_t tv_strlen(const typval_T *const tv)
+static inline size_t tv_strlen(const typval_T *tv)
   REAL_FATTR_ALWAYS_INLINE REAL_FATTR_PURE REAL_FATTR_WARN_UNUSED_RESULT
   REAL_FATTR_NONNULL_ALL;
 
diff --git a/src/nvim/eval/userfunc.c b/src/nvim/eval/userfunc.c
index b0a56c4440..22c5b1954d 100644
--- a/src/nvim/eval/userfunc.c
+++ b/src/nvim/eval/userfunc.c
@@ -3,28 +3,49 @@
 
 // User defined function support
 
+#include <assert.h>
+#include <ctype.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "lauxlib.h"
 #include "nvim/ascii.h"
+#include "nvim/autocmd.h"
+#include "nvim/buffer_defs.h"
 #include "nvim/charset.h"
 #include "nvim/debugger.h"
-#include "nvim/edit.h"
 #include "nvim/eval.h"
 #include "nvim/eval/encode.h"
 #include "nvim/eval/funcs.h"
+#include "nvim/eval/typval.h"
 #include "nvim/eval/userfunc.h"
 #include "nvim/eval/vars.h"
+#include "nvim/ex_cmds_defs.h"
 #include "nvim/ex_docmd.h"
 #include "nvim/ex_eval.h"
 #include "nvim/ex_getln.h"
-#include "nvim/fileio.h"
 #include "nvim/getchar.h"
+#include "nvim/gettext.h"
 #include "nvim/globals.h"
 #include "nvim/insexpand.h"
+#include "nvim/keycodes.h"
 #include "nvim/lua/executor.h"
+#include "nvim/macros.h"
+#include "nvim/mbyte.h"
+#include "nvim/memline_defs.h"
+#include "nvim/memory.h"
+#include "nvim/message.h"
+#include "nvim/option_defs.h"
 #include "nvim/os/input.h"
+#include "nvim/path.h"
 #include "nvim/profile.h"
 #include "nvim/regexp.h"
 #include "nvim/runtime.h"
 #include "nvim/search.h"
+#include "nvim/strings.h"
+#include "nvim/types.h"
 #include "nvim/ui.h"
 #include "nvim/vim.h"
 
@@ -48,6 +69,8 @@ static char *e_funcexts = N_("E122: Function %s already exists, add ! to replace
 static char *e_funcdict = N_("E717: Dictionary entry already exists");
 static char *e_funcref = N_("E718: Funcref required");
 static char *e_nofunc = N_("E130: Unknown function: %s");
+static char e_no_white_space_allowed_before_str_str[]
+  = N_("E1068: No white space allowed before '%s': %s");
 
 void func_init(void)
 {
@@ -61,7 +84,7 @@ hashtab_T *func_tbl_get(void)
 }
 
 /// Get function arguments.
-static int get_function_args(char **argp, char_u endchar, garray_T *newargs, int *varargs,
+static int get_function_args(char **argp, char endchar, garray_T *newargs, int *varargs,
                              garray_T *default_args, bool skip)
 {
   bool mustend = false;
@@ -71,10 +94,10 @@ static int get_function_args(char **argp, char_u endchar, garray_T *newargs, int
   int i;
 
   if (newargs != NULL) {
-    ga_init(newargs, (int)sizeof(char_u *), 3);
+    ga_init(newargs, (int)sizeof(char *), 3);
   }
   if (default_args != NULL) {
-    ga_init(default_args, (int)sizeof(char_u *), 3);
+    ga_init(default_args, (int)sizeof(char *), 3);
   }
 
   if (varargs != NULL) {
@@ -83,7 +106,7 @@ static int get_function_args(char **argp, char_u endchar, garray_T *newargs, int
 
   // Isolate the arguments: "arg1, arg2, ...)"
   bool any_default = false;
-  while (*p != (char)endchar) {
+  while (*p != endchar) {
     if (p[0] == '.' && p[1] == '.' && p[2] == '.') {
       if (varargs != NULL) {
         *varargs = true;
@@ -95,9 +118,9 @@ static int get_function_args(char **argp, char_u endchar, garray_T *newargs, int
       while (ASCII_ISALNUM(*p) || *p == '_') {
         p++;
       }
-      if (arg == p || isdigit(*arg)
-          || (p - arg == 9 && STRNCMP(arg, "firstline", 9) == 0)
-          || (p - arg == 8 && STRNCMP(arg, "lastline", 8) == 0)) {
+      if (arg == p || isdigit((uint8_t)(*arg))
+          || (p - arg == 9 && strncmp(arg, "firstline", 9) == 0)
+          || (p - arg == 8 && strncmp(arg, "lastline", 8) == 0)) {
         if (!skip) {
           semsg(_("E125: Illegal argument: %s"), arg);
         }
@@ -149,6 +172,15 @@ static int get_function_args(char **argp, char_u endchar, garray_T *newargs, int
         emsg(_("E989: Non-default argument follows default argument"));
         mustend = true;
       }
+
+      if (ascii_iswhite(*p) && *skipwhite(p) == ',') {
+        // Be tolerant when skipping
+        if (!skip) {
+          semsg(_(e_no_white_space_allowed_before_str_str), ",", p);
+          goto err_ret;
+        }
+        p = skipwhite(p);
+      }
       if (*p == ',') {
         p++;
       } else {
@@ -156,14 +188,14 @@ static int get_function_args(char **argp, char_u endchar, garray_T *newargs, int
       }
     }
     p = skipwhite(p);
-    if (mustend && *p != (char)endchar) {
+    if (mustend && *p != endchar) {
       if (!skip) {
         semsg(_(e_invarg2), *argp);
       }
       break;
     }
   }
-  if (*p != (char)endchar) {
+  if (*p != endchar) {
     goto err_ret;
   }
   p++;  // skip "endchar"
@@ -197,21 +229,21 @@ static void register_closure(ufunc_T *fp)
 }
 
 /// @return  a name for a lambda.  Returned in static memory.
-char_u *get_lambda_name(void)
+char *get_lambda_name(void)
 {
-  static char_u name[30];
+  static char name[30];
   static int lambda_no = 0;
 
-  snprintf((char *)name, sizeof(name), "<lambda>%d", ++lambda_no);
+  snprintf(name, sizeof(name), "<lambda>%d", ++lambda_no);
   return name;
 }
 
-static void set_ufunc_name(ufunc_T *fp, char_u *name)
+static void set_ufunc_name(ufunc_T *fp, char *name)
 {
   STRCPY(fp->uf_name, name);
 
-  if (name[0] == K_SPECIAL) {
-    fp->uf_name_exp = xmalloc(STRLEN(name) + 3);
+  if ((uint8_t)name[0] == K_SPECIAL) {
+    fp->uf_name_exp = xmalloc(strlen(name) + 3);
     STRCPY(fp->uf_name_exp, "<SNR>");
     STRCAT(fp->uf_name_exp, fp->uf_name + 3);
   }
@@ -228,13 +260,13 @@ int get_lambda_tv(char **arg, typval_T *rettv, bool evaluate)
   partial_T *pt = NULL;
   int varargs;
   int ret;
-  char_u *start = (char_u *)skipwhite(*arg + 1);
-  char_u *s, *e;
+  char *start = skipwhite(*arg + 1);
+  char *s, *e;
   bool *old_eval_lavars = eval_lavars_used;
   bool eval_lavars = false;
 
   // First, check if this is a lambda expression. "->" must exists.
-  ret = get_function_args((char **)&start, '-', NULL, NULL, NULL, true);
+  ret = get_function_args(&start, '-', NULL, NULL, NULL, true);
   if (ret == FAIL || *start != '>') {
     return NOTDONE;
   }
@@ -258,38 +290,39 @@ int get_lambda_tv(char **arg, typval_T *rettv, bool evaluate)
 
   // Get the start and the end of the expression.
   *arg = skipwhite((*arg) + 1);
-  s = (char_u *)(*arg);
+  s = *arg;
   ret = skip_expr(arg);
   if (ret == FAIL) {
     goto errret;
   }
-  e = (char_u *)(*arg);
+  e = *arg;
   *arg = skipwhite(*arg);
   if (**arg != '}') {
+    semsg(_("E451: Expected }: %s"), *arg);
     goto errret;
   }
   (*arg)++;
 
   if (evaluate) {
     int flags = 0;
-    char_u *p;
+    char *p;
     garray_T newlines;
 
-    char_u *name = get_lambda_name();
+    char *name = get_lambda_name();
 
-    fp = xcalloc(1, offsetof(ufunc_T, uf_name) + STRLEN(name) + 1);
+    fp = xcalloc(1, offsetof(ufunc_T, uf_name) + strlen(name) + 1);
     pt = xcalloc(1, sizeof(partial_T));
 
-    ga_init(&newlines, (int)sizeof(char_u *), 1);
+    ga_init(&newlines, (int)sizeof(char *), 1);
     ga_grow(&newlines, 1);
 
     // Add "return " before the expression.
     size_t len = (size_t)(7 + e - s + 1);
-    p = (char_u *)xmalloc(len);
-    ((char **)(newlines.ga_data))[newlines.ga_len++] = (char *)p;
+    p = xmalloc(len);
+    ((char **)(newlines.ga_data))[newlines.ga_len++] = p;
     STRCPY(p, "return ");
-    STRLCPY(p + 7, s, e - s + 1);
-    if (strstr((char *)p + 7, "a:") == NULL) {
+    xstrlcpy(p + 7, s, (size_t)(e - s) + 1);
+    if (strstr(p + 7, "a:") == NULL) {
       // No a: variables are used for sure.
       flags |= FC_NOARGS;
     }
@@ -298,7 +331,7 @@ int get_lambda_tv(char **arg, typval_T *rettv, bool evaluate)
     set_ufunc_name(fp, name);
     hash_add(&func_hashtab, UF2HIKEY(fp));
     fp->uf_args = newargs;
-    ga_init(&fp->uf_def_args, (int)sizeof(char_u *), 1);
+    ga_init(&fp->uf_def_args, (int)sizeof(char *), 1);
     fp->uf_lines = newlines;
     if (current_funccal != NULL && eval_lavars) {
       flags |= FC_CLOSURE;
@@ -351,7 +384,7 @@ errret:
 ///                          was not found.
 ///
 /// @return name of the function.
-char_u *deref_func_name(const char *name, int *lenp, partial_T **const partialp, bool no_autoload)
+char *deref_func_name(const char *name, int *lenp, partial_T **const partialp, bool no_autoload)
   FUNC_ATTR_NONNULL_ARG(1, 2)
 {
   if (partialp != NULL) {
@@ -362,10 +395,10 @@ char_u *deref_func_name(const char *name, int *lenp, partial_T **const partialp,
   if (v != NULL && v->di_tv.v_type == VAR_FUNC) {
     if (v->di_tv.vval.v_string == NULL) {  // just in case
       *lenp = 0;
-      return (char_u *)"";
+      return "";
     }
     *lenp = (int)strlen(v->di_tv.vval.v_string);
-    return (char_u *)v->di_tv.vval.v_string;
+    return v->di_tv.vval.v_string;
   }
 
   if (v != NULL && v->di_tv.v_type == VAR_PARTIAL) {
@@ -373,31 +406,31 @@ char_u *deref_func_name(const char *name, int *lenp, partial_T **const partialp,
 
     if (pt == NULL) {  // just in case
       *lenp = 0;
-      return (char_u *)"";
+      return "";
     }
     if (partialp != NULL) {
       *partialp = pt;
     }
-    char_u *s = (char_u *)partial_name(pt);
-    *lenp = (int)STRLEN(s);
+    char *s = partial_name(pt);
+    *lenp = (int)strlen(s);
     return s;
   }
 
-  return (char_u *)name;
+  return (char *)name;
 }
 
 /// Give an error message with a function name.  Handle <SNR> things.
 ///
 /// @param ermsg must be passed without translation (use N_() instead of _()).
 /// @param name function name
-void emsg_funcname(char *ermsg, const char_u *name)
+void emsg_funcname(char *ermsg, const char *name)
 {
-  char_u *p;
+  char *p;
 
-  if (*name == K_SPECIAL) {
-    p = (char_u *)concat_str("<SNR>", (char *)name + 3);
+  if ((uint8_t)(*name) == K_SPECIAL) {
+    p = concat_str("<SNR>", name + 3);
   } else {
-    p = (char_u *)name;
+    p = (char *)name;
   }
 
   semsg(_(ermsg), p);
@@ -415,7 +448,7 @@ void emsg_funcname(char *ermsg, const char_u *name)
 /// @param funcexe  various values
 ///
 /// @return  OK or FAIL.
-int get_func_tv(const char_u *name, int len, typval_T *rettv, char **arg, funcexe_T *funcexe)
+int get_func_tv(const char *name, int len, typval_T *rettv, char **arg, funcexe_T *funcexe)
 {
   char *argp;
   int ret = OK;
@@ -449,7 +482,7 @@ int get_func_tv(const char_u *name, int len, typval_T *rettv, char **arg, funcex
     int i = 0;
 
     if (get_vim_var_nr(VV_TESTING)) {
-      // Prepare for calling garbagecollect_for_testing(), need to know
+      // Prepare for calling test_garbagecollect_now(), need to know
       // what variables are used on the call stack.
       if (funcargs.ga_itemsize == 0) {
         ga_init(&funcargs, (int)sizeof(typval_T *), 50);
@@ -459,7 +492,7 @@ int get_func_tv(const char_u *name, int len, typval_T *rettv, char **arg, funcex
         ((typval_T **)funcargs.ga_data)[funcargs.ga_len++] = &argvars[i];
       }
     }
-    ret = call_func((char *)name, len, rettv, argcount, argvars, funcexe);
+    ret = call_func(name, len, rettv, argcount, argvars, funcexe);
 
     funcargs.ga_len -= i;
   } else if (!aborting()) {
@@ -549,9 +582,9 @@ static char *fname_trans_sid(const char *const name, char *const fname_buf, char
 /// Find a function by name, return pointer to it in ufuncs.
 ///
 /// @return  NULL for unknown function.
-ufunc_T *find_func(const char_u *name)
+ufunc_T *find_func(const char *name)
 {
-  hashitem_T *hi = hash_find(&func_hashtab, (char *)name);
+  hashitem_T *hi = hash_find(&func_hashtab, name);
   if (!HASHITEM_EMPTY(hi)) {
     return HI2UF(hi);
   }
@@ -561,9 +594,9 @@ ufunc_T *find_func(const char_u *name)
 /// Copy the function name of "fp" to buffer "buf".
 /// "buf" must be able to hold the function name plus three bytes.
 /// Takes care of script-local function names.
-static void cat_func_name(char_u *buf, ufunc_T *fp)
+static void cat_func_name(char *buf, ufunc_T *fp)
 {
-  if (fp->uf_name[0] == K_SPECIAL) {
+  if ((uint8_t)fp->uf_name[0] == K_SPECIAL) {
     STRCPY(buf, "<SNR>");
     STRCAT(buf, fp->uf_name + 3);
   } else {
@@ -578,7 +611,7 @@ static void add_nr_var(dict_T *dp, dictitem_T *v, char *name, varnumber_T nr)
   STRCPY(v->di_key, name);
 #endif
   v->di_flags = DI_FLAGS_RO | DI_FLAGS_FIX;
-  tv_dict_add(dp, v);
+  hash_add(&dp->dv_hashtab, (char *)v->di_key);
   v->di_tv.v_type = VAR_NUMBER;
   v->di_tv.v_lock = VAR_FIXED;
   v->di_tv.vval.v_number = nr;
@@ -813,7 +846,7 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
   int fixvar_idx = 0;           // index in fixvar[]
   int ai;
   bool islambda = false;
-  char_u numbuf[NUMBUFLEN];
+  char numbuf[NUMBUFLEN];
   char *name;
   typval_T *tv_to_free[MAX_FUNC_ARGS];
   int tv_to_free_len = 0;
@@ -855,7 +888,7 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
   ga_init(&fc->fc_funcs, sizeof(ufunc_T *), 1);
   func_ptr_ref(fp);
 
-  if (STRNCMP(fp->uf_name, "<lambda>", 8) == 0) {
+  if (strncmp(fp->uf_name, "<lambda>", 8) == 0) {
     islambda = true;
   }
 
@@ -874,7 +907,7 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
     STRCPY(name, "self");
 #endif
     v->di_flags = DI_FLAGS_RO | DI_FLAGS_FIX;
-    tv_dict_add(&fc->l_vars, v);
+    hash_add(&fc->l_vars.dv_hashtab, (char *)v->di_key);
     v->di_tv.v_type = VAR_DICT;
     v->di_tv.v_lock = VAR_UNLOCKED;
     v->di_tv.vval.v_dict = selfdict;
@@ -900,7 +933,7 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
     STRCPY(name, "000");
 #endif
     v->di_flags = DI_FLAGS_RO | DI_FLAGS_FIX;
-    tv_dict_add(&fc->l_avars, v);
+    hash_add(&fc->l_avars.dv_hashtab, (char *)v->di_key);
     v->di_tv.v_type = VAR_LIST;
     v->di_tv.v_lock = VAR_FIXED;
     v->di_tv.vval.v_list = &fc->l_varlist;
@@ -952,8 +985,8 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
         break;
       }
       // "..." argument a:1, a:2, etc.
-      snprintf((char *)numbuf, sizeof(numbuf), "%d", ai + 1);
-      name = (char *)numbuf;
+      snprintf(numbuf, sizeof(numbuf), "%d", ai + 1);
+      name = numbuf;
     }
     if (fixvar_idx < FIXVAR_CNT && strlen(name) <= VAR_SHORT_LEN) {
       v = (dictitem_T *)&fc->fixvar[fixvar_idx++];
@@ -978,16 +1011,16 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
       // Named arguments can be accessed without the "a:" prefix in lambda
       // expressions. Add to the l: dict.
       tv_copy(&v->di_tv, &v->di_tv);
-      tv_dict_add(&fc->l_vars, v);
+      hash_add(&fc->l_vars.dv_hashtab, (char *)v->di_key);
     } else {
-      tv_dict_add(&fc->l_avars, v);
+      hash_add(&fc->l_avars.dv_hashtab, (char *)v->di_key);
     }
 
     if (ai >= 0 && ai < MAX_FUNC_ARGS) {
       listitem_T *li = &fc->l_listitems[ai];
 
       *TV_LIST_ITEM_TV(li) = argvars[i];
-      TV_LIST_ITEM_TV(li)->v_lock =  VAR_FIXED;
+      TV_LIST_ITEM_TV(li)->v_lock = VAR_FIXED;
       tv_list_append(&fc->l_varlist, li);
     }
   }
@@ -1193,9 +1226,9 @@ void call_user_func(ufunc_T *fp, int argcount, typval_T *argvars, typval_T *rett
 /// For the first we only count the name stored in func_hashtab as a reference,
 /// using function() does not count as a reference, because the function is
 /// looked up by name.
-static bool func_name_refcount(char_u *name)
+static bool func_name_refcount(const char *name)
 {
-  return isdigit(*name) || *name == '<';
+  return isdigit((uint8_t)(*name)) || *name == '<';
 }
 
 /// Call a user function after checking the arguments.
@@ -1265,7 +1298,7 @@ void free_all_functions(void)
   ufunc_T *fp;
   uint64_t skipped = 0;
   uint64_t todo = 1;
-  uint64_t used;
+  int changed;
 
   // Clean up the current_funccal chain and the funccal stack.
   while (current_funccal != NULL) {
@@ -1289,9 +1322,9 @@ void free_all_functions(void)
         if (func_name_refcount(fp->uf_name)) {
           skipped++;
         } else {
-          used = func_hashtab.ht_used;
+          changed = func_hashtab.ht_changed;
           func_clear(fp, true);
-          if (used != func_hashtab.ht_used) {
+          if (changed != func_hashtab.ht_changed) {
             skipped = 0;
             break;
           }
@@ -1335,10 +1368,10 @@ void free_all_functions(void)
 /// @param[in]   len    length of "name", or -1 for NUL terminated.
 ///
 /// @return true if "name" looks like a builtin function name: starts with a
-/// lower case letter and doesn't contain AUTOLOAD_CHAR.
+/// lower case letter and doesn't contain AUTOLOAD_CHAR or ':'.
 static bool builtin_function(const char *name, int len)
 {
-  if (!ASCII_ISLOWER(name[0])) {
+  if (!ASCII_ISLOWER(name[0]) || name[1] == ':') {
     return false;
   }
 
@@ -1349,7 +1382,7 @@ static bool builtin_function(const char *name, int len)
   return p == NULL;
 }
 
-int func_call(char_u *name, typval_T *args, partial_T *partial, dict_T *selfdict, typval_T *rettv)
+int func_call(char *name, typval_T *args, partial_T *partial, dict_T *selfdict, typval_T *rettv)
 {
   typval_T argv[MAX_FUNC_ARGS + 1];
   int argc = 0;
@@ -1371,7 +1404,7 @@ int func_call(char_u *name, typval_T *args, partial_T *partial, dict_T *selfdict
   funcexe.fe_evaluate = true;
   funcexe.fe_partial = partial;
   funcexe.fe_selfdict = selfdict;
-  r = call_func((char *)name, -1, rettv, argc, argv, &funcexe);
+  r = call_func(name, -1, rettv, argc, argv, &funcexe);
 
 func_call_skip_call:
   // Free the arguments.
@@ -1382,9 +1415,27 @@ func_call_skip_call:
   return r;
 }
 
+/// call the 'callback' function and return the result as a number.
+/// Returns -2 when calling the function fails.  Uses argv[0] to argv[argc - 1]
+/// for the function arguments. argv[argc] should have type VAR_UNKNOWN.
+///
+/// @param argcount  number of "argvars"
+/// @param argvars   vars for arguments, must have "argcount" PLUS ONE elements!
+varnumber_T callback_call_retnr(Callback *callback, int argcount, typval_T *argvars)
+{
+  typval_T rettv;
+  if (!callback_call(callback, argcount, argvars, &rettv)) {
+    return -2;
+  }
+
+  varnumber_T retval = tv_get_number_chk(&rettv, NULL);
+  tv_clear(&rettv);
+  return retval;
+}
+
 /// Give an error message for the result of a function.
 /// Nothing if "error" is FCERR_NONE.
-static void user_func_error(int error, const char_u *name)
+static void user_func_error(int error, const char *name)
   FUNC_ATTR_NONNULL_ALL
 {
   switch (error) {
@@ -1401,16 +1452,13 @@ static void user_func_error(int error, const char_u *name)
     emsg_funcname(_(e_toomanyarg), name);
     break;
   case FCERR_TOOFEW:
-    emsg_funcname(N_("E119: Not enough arguments for function: %s"),
-                  name);
+    emsg_funcname(N_("E119: Not enough arguments for function: %s"), name);
     break;
   case FCERR_SCRIPT:
-    emsg_funcname(N_("E120: Using <SID> not in a script context: %s"),
-                  name);
+    emsg_funcname(N_("E120: Using <SID> not in a script context: %s"), name);
     break;
   case FCERR_DICT:
-    emsg_funcname(N_("E725: Calling dict function without Dictionary: %s"),
-                  name);
+    emsg_funcname(N_("E725: Calling dict function without Dictionary: %s"), name);
     break;
   }
 }
@@ -1477,7 +1525,7 @@ int call_func(const char *funcname, int len, typval_T *rettv, int argcount_in, t
     // Make a copy of the name, if it comes from a funcref variable it could
     // be changed or deleted in the called function.
     name = xstrnsave(funcname, (size_t)len);
-    fname = fname_trans_sid(name, (char *)fname_buf, &tofree, &error);
+    fname = fname_trans_sid(name, fname_buf, &tofree, &error);
   }
 
   if (funcexe->fe_doesrange != NULL) {
@@ -1532,7 +1580,7 @@ int call_func(const char *funcname, int len, typval_T *rettv, int argcount_in, t
     } else if (fp != NULL || !builtin_function((const char *)rfname, -1)) {
       // User defined function.
       if (fp == NULL) {
-        fp = find_func((char_u *)rfname);
+        fp = find_func(rfname);
       }
 
       // Trigger FuncUndefined event, may load the function.
@@ -1540,13 +1588,13 @@ int call_func(const char *funcname, int len, typval_T *rettv, int argcount_in, t
           && apply_autocmds(EVENT_FUNCUNDEFINED, rfname, rfname, true, NULL)
           && !aborting()) {
         // executed an autocommand, search for the function again
-        fp = find_func((char_u *)rfname);
+        fp = find_func(rfname);
       }
       // Try loading a package.
       if (fp == NULL && script_autoload((const char *)rfname, strlen(rfname),
                                         true) && !aborting()) {
         // Loaded a package, search for the function again.
-        fp = find_func((char_u *)rfname);
+        fp = find_func(rfname);
       }
 
       if (fp != NULL && (fp->uf_flags & FC_DELETED)) {
@@ -1564,11 +1612,11 @@ int call_func(const char *funcname, int len, typval_T *rettv, int argcount_in, t
     } else if (funcexe->fe_basetv != NULL) {
       // expr->method(): Find the method name in the table, call its
       // implementation with the base as one of the arguments.
-      error = call_internal_method((char_u *)fname, argcount, argvars, rettv,
+      error = call_internal_method(fname, argcount, argvars, rettv,
                                    funcexe->fe_basetv);
     } else {
       // Find the function name in the table, call its implementation.
-      error = call_internal_func((char_u *)fname, argcount, argvars, rettv);
+      error = call_internal_func(fname, argcount, argvars, rettv);
     }
     // The function call (or "FuncUndefined" autocommand sequence) might
     // have been aborted by an error, an interrupt, or an explicitly thrown
@@ -1588,7 +1636,7 @@ theend:
   // Report an error unless the argument evaluation or function call has been
   // cancelled due to an aborting error, an interrupt, or an exception.
   if (!aborting()) {
-    user_func_error(error, (name != NULL) ? (char_u *)name : (char_u *)funcname);
+    user_func_error(error, (name != NULL) ? name : funcname);
   }
 
   // clear the copies made from the partial
@@ -1602,6 +1650,11 @@ theend:
   return ret;
 }
 
+char *printable_func_name(ufunc_T *fp)
+{
+  return fp->uf_name_exp != NULL ? fp->uf_name_exp : fp->uf_name;
+}
+
 /// List the head of the function: "name(arg1, arg2)".
 ///
 /// @param[in]  fp      Function pointer.
@@ -1671,12 +1724,12 @@ static void list_func_head(ufunc_T *fp, int indent, bool force)
 /// @param partial  return: partial of a FuncRef
 ///
 /// @return the function name in allocated memory, or NULL for failure.
-char_u *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, partial_T **partial)
+char *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, partial_T **partial)
   FUNC_ATTR_NONNULL_ARG(1)
 {
   char *name = NULL;
-  const char_u *start;
-  const char_u *end;
+  const char *start;
+  const char *end;
   int lead;
   int len;
   lval_T lv;
@@ -1684,7 +1737,7 @@ char_u *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, pa
   if (fdp != NULL) {
     CLEAR_POINTER(fdp);
   }
-  start = (char_u *)(*pp);
+  start = *pp;
 
   // Check for hard coded <SNR>: already translated function ID (from a user
   // command).
@@ -1692,19 +1745,19 @@ char_u *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, pa
       && (*pp)[2] == KE_SNR) {
     *pp += 3;
     len = get_id_len((const char **)pp) + 3;
-    return (char_u *)xmemdupz(start, (size_t)len);
+    return xmemdupz(start, (size_t)len);
   }
 
   // A name starting with "<SID>" or "<SNR>" is local to a script.  But
   // don't skip over "s:", get_lval() needs it for "s:dict.func".
-  lead = eval_fname_script((const char *)start);
+  lead = eval_fname_script(start);
   if (lead > 2) {
     start += lead;
   }
 
   // Note that TFN_ flags use the same values as GLV_ flags.
-  end = (char_u *)get_lval((char *)start, NULL, &lv, false, skip, flags | GLV_READ_ONLY,
-                           lead > 2 ? 0 : FNE_CHECK_START);
+  end = get_lval((char *)start, NULL, &lv, false, skip, flags | GLV_READ_ONLY,
+                 lead > 2 ? 0 : FNE_CHECK_START);
   if (end == start) {
     if (!skip) {
       emsg(_("E129: Function name required"));
@@ -1728,7 +1781,7 @@ char_u *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, pa
   if (lv.ll_tv != NULL) {
     if (fdp != NULL) {
       fdp->fd_dict = lv.ll_dict;
-      fdp->fd_newkey = (char_u *)lv.ll_newkey;
+      fdp->fd_newkey = lv.ll_newkey;
       lv.ll_newkey = NULL;
       fdp->fd_di = lv.ll_di;
     }
@@ -1738,7 +1791,7 @@ char_u *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, pa
     } else if (lv.ll_tv->v_type == VAR_PARTIAL
                && lv.ll_tv->vval.v_partial != NULL) {
       if (is_luafunc(lv.ll_tv->vval.v_partial) && *end == '.') {
-        len = check_luafunc_name((const char *)end + 1, true);
+        len = check_luafunc_name(end + 1, true);
         if (len == 0) {
           semsg(e_invexpr2, "v:lua");
           goto theend;
@@ -1775,15 +1828,14 @@ char_u *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, pa
   // Check if the name is a Funcref.  If so, use the value.
   if (lv.ll_exp_name != NULL) {
     len = (int)strlen(lv.ll_exp_name);
-    name = (char *)deref_func_name(lv.ll_exp_name, &len, partial,
-                                   flags & TFN_NO_AUTOLOAD);
+    name = deref_func_name(lv.ll_exp_name, &len, partial,
+                           flags & TFN_NO_AUTOLOAD);
     if ((const char *)name == lv.ll_exp_name) {
       name = NULL;
     }
   } else if (!(flags & TFN_NO_DEREF)) {
-    len = (int)(end - (char_u *)(*pp));
-    name = (char *)deref_func_name((const char *)(*pp), &len, partial,
-                                   flags & TFN_NO_AUTOLOAD);
+    len = (int)(end - *pp);
+    name = deref_func_name(*pp, &len, partial, flags & TFN_NO_AUTOLOAD);
     if (name == *pp) {
       name = NULL;
     }
@@ -1791,7 +1843,7 @@ char_u *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, pa
   if (name != NULL) {
     name = xstrdup(name);
     *pp = (char *)end;
-    if (STRNCMP(name, "<SNR>", 5) == 0) {
+    if (strncmp(name, "<SNR>", 5) == 0) {
       // Change "<SNR>" to the byte sequence.
       name[0] = (char)K_SPECIAL;
       name[1] = (char)KS_EXTRA;
@@ -1818,7 +1870,7 @@ char_u *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, pa
       lv.ll_name += 2;
       lv.ll_name_len -= 2;
     }
-    len = (int)((const char *)end - lv.ll_name);
+    len = (int)(end - lv.ll_name);
   }
 
   size_t sid_buf_len = 0;
@@ -1849,7 +1901,7 @@ char_u *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, pa
   }
 
   if (!skip && !(flags & TFN_QUIET) && !(flags & TFN_NO_DEREF)) {
-    char_u *cp = xmemrchr(lv.ll_name, ':', lv.ll_name_len);
+    char *cp = xmemrchr(lv.ll_name, ':', lv.ll_name_len);
 
     if (cp != NULL && cp < end) {
       semsg(_("E884: Function name cannot contain a colon: %s"), start);
@@ -1872,11 +1924,96 @@ char_u *trans_function_name(char **pp, bool skip, int flags, funcdict_T *fdp, pa
 
 theend:
   clear_lval(&lv);
-  return (char_u *)name;
+  return name;
+}
+
+/// If the "funcname" starts with "s:" or "<SID>", then expands it to the
+/// current script ID and returns the expanded function name. The caller should
+/// free the returned name. If not called from a script context or the function
+/// name doesn't start with these prefixes, then returns NULL.
+/// This doesn't check whether the script-local function exists or not.
+char *get_scriptlocal_funcname(char *funcname)
+{
+  if (funcname == NULL) {
+    return NULL;
+  }
+
+  if (strncmp(funcname, "s:", 2) != 0
+      && strncmp(funcname, "<SID>", 5) != 0) {
+    // The function name is not a script-local function name
+    return NULL;
+  }
+
+  if (!SCRIPT_ID_VALID(current_sctx.sc_sid)) {
+    emsg(_(e_usingsid));
+    return NULL;
+  }
+
+  char sid_buf[25];
+  // Expand s: and <SID> prefix into <SNR>nr_<name>
+  snprintf(sid_buf, sizeof(sid_buf), "<SNR>%" PRId64 "_",
+           (int64_t)current_sctx.sc_sid);
+  const int off = *funcname == 's' ? 2 : 5;
+  char *newname = xmalloc(strlen(sid_buf) + strlen(funcname + off) + 1);
+  STRCPY(newname, sid_buf);
+  STRCAT(newname, funcname + off);
+
+  return newname;
+}
+
+/// Call trans_function_name(), except that a lambda is returned as-is.
+/// Returns the name in allocated memory.
+char *save_function_name(char **name, bool skip, int flags, funcdict_T *fudi)
+{
+  char *p = *name;
+  char *saved;
+
+  if (strncmp(p, "<lambda>", 8) == 0) {
+    p += 8;
+    (void)getdigits(&p, false, 0);
+    saved = xstrndup(*name, (size_t)(p - *name));
+    if (fudi != NULL) {
+      CLEAR_POINTER(fudi);
+    }
+  } else {
+    saved = trans_function_name(&p, skip, flags, fudi, NULL);
+  }
+  *name = p;
+  return saved;
 }
 
 #define MAX_FUNC_NESTING 50
 
+/// List functions.
+///
+/// @param regmatch  When NULL, all of them.
+///                  Otherwise functions matching "regmatch".
+static void list_functions(regmatch_T *regmatch)
+{
+  const int changed = func_hashtab.ht_changed;
+  size_t todo = func_hashtab.ht_used;
+  const hashitem_T *const ht_array = func_hashtab.ht_array;
+
+  for (const hashitem_T *hi = ht_array; todo > 0 && !got_int; hi++) {
+    if (!HASHITEM_EMPTY(hi)) {
+      ufunc_T *fp = HI2UF(hi);
+      todo--;
+      if ((fp->uf_flags & FC_DEAD) == 0
+          && (regmatch == NULL
+              ? (!message_filtered((char *)fp->uf_name)
+                 && !func_name_refcount(fp->uf_name))
+              : (!isdigit((uint8_t)(*fp->uf_name))
+                 && vim_regexec(regmatch, (char *)fp->uf_name, 0)))) {
+        list_func_head(fp, false, false);
+        if (changed != func_hashtab.ht_changed) {
+          emsg(_("E454: function list was modified"));
+          return;
+        }
+      }
+    }
+  }
+}
+
 /// ":function"
 void ex_function(exarg_T *eap)
 {
@@ -1903,7 +2040,6 @@ void ex_function(exarg_T *eap)
   static int func_nr = 0;           // number for nameless function
   int paren;
   hashtab_T *ht;
-  int todo;
   hashitem_T *hi;
   linenr_T sourcing_lnum_off;
   linenr_T sourcing_lnum_top;
@@ -1916,19 +2052,7 @@ void ex_function(exarg_T *eap)
   // ":function" without argument: list functions.
   if (ends_excmd(*eap->arg)) {
     if (!eap->skip) {
-      todo = (int)func_hashtab.ht_used;
-      for (hi = func_hashtab.ht_array; todo > 0 && !got_int; hi++) {
-        if (!HASHITEM_EMPTY(hi)) {
-          todo--;
-          fp = HI2UF(hi);
-          if (message_filtered((char *)fp->uf_name)) {
-            continue;
-          }
-          if (!func_name_refcount(fp->uf_name)) {
-            list_func_head(fp, false, false);
-          }
-        }
-      }
+      list_functions(NULL);
     }
     eap->nextcmd = check_nextcmd(eap->arg);
     return;
@@ -1936,7 +2060,7 @@ void ex_function(exarg_T *eap)
 
   // ":function /pat": list functions matching pattern.
   if (*eap->arg == '/') {
-    p = skip_regexp(eap->arg + 1, '/', true, NULL);
+    p = skip_regexp(eap->arg + 1, '/', true);
     if (!eap->skip) {
       regmatch_T regmatch;
 
@@ -1946,18 +2070,7 @@ void ex_function(exarg_T *eap)
       *p = c;
       if (regmatch.regprog != NULL) {
         regmatch.rm_ic = p_ic;
-
-        todo = (int)func_hashtab.ht_used;
-        for (hi = func_hashtab.ht_array; todo > 0 && !got_int; hi++) {
-          if (!HASHITEM_EMPTY(hi)) {
-            todo--;
-            fp = HI2UF(hi);
-            if (!isdigit(*fp->uf_name)
-                && vim_regexec(&regmatch, (char *)fp->uf_name, 0)) {
-              list_func_head(fp, false, false);
-            }
-          }
-        }
+        list_functions(&regmatch);
         vim_regfree(regmatch.regprog);
       }
     }
@@ -1983,14 +2096,7 @@ void ex_function(exarg_T *eap)
   // s:func      script-local function name
   // g:func      global function name, same as "func"
   p = eap->arg;
-  if (strncmp(p, "<lambda>", 8) == 0) {
-    p += 8;
-    (void)getdigits(&p, false, 0);
-    name = xstrndup(eap->arg, (size_t)(p - eap->arg));
-    CLEAR_FIELD(fudi);
-  } else {
-    name = (char *)trans_function_name(&p, eap->skip, TFN_NO_AUTOLOAD, &fudi, NULL);
-  }
+  name = save_function_name(&p, eap->skip, TFN_NO_AUTOLOAD, &fudi);
   paren = (vim_strchr(p, '(') != NULL);
   if (name == NULL && (fudi.fd_dict == NULL || !paren) && !eap->skip) {
     // Return on an invalid expression in braces, unless the expression
@@ -2002,9 +2108,8 @@ void ex_function(exarg_T *eap)
       }
       xfree(fudi.fd_newkey);
       return;
-    } else {
-      eap->skip = true;
     }
+    eap->skip = true;
   }
 
   // An error in a function call during evaluation of an expression in magic
@@ -2028,7 +2133,7 @@ void ex_function(exarg_T *eap)
       *p = NUL;
     }
     if (!eap->skip && !got_int) {
-      fp = find_func((char_u *)name);
+      fp = find_func(name);
       if (fp != NULL) {
         list_func_head(fp, !eap->forceit, eap->forceit);
         for (int j = 0; j < fp->uf_lines.ga_len && !got_int; j++) {
@@ -2054,7 +2159,7 @@ void ex_function(exarg_T *eap)
           msg_puts(eap->forceit ? "endfunction" : "   endfunction");
         }
       } else {
-        emsg_funcname(N_("E123: Undefined function: %s"), (char_u *)name);
+        emsg_funcname(N_("E123: Undefined function: %s"), name);
       }
     }
     goto ret_free;
@@ -2074,8 +2179,8 @@ void ex_function(exarg_T *eap)
   }
   p = skipwhite(p + 1);
 
-  ga_init(&newargs, (int)sizeof(char_u *), 3);
-  ga_init(&newlines, (int)sizeof(char_u *), 3);
+  ga_init(&newargs, (int)sizeof(char *), 3);
+  ga_init(&newlines, (int)sizeof(char *), 3);
 
   if (!eap->skip) {
     // Check the name of the function.  Unless it's a dictionary function
@@ -2083,7 +2188,7 @@ void ex_function(exarg_T *eap)
     if (name != NULL) {
       arg = name;
     } else {
-      arg = (char *)fudi.fd_newkey;
+      arg = fudi.fd_newkey;
     }
     if (arg != NULL && (fudi.fd_di == NULL || !tv_is_func(fudi.fd_di->di_tv))) {
       int j = ((uint8_t)(*arg) == K_SPECIAL) ? 3 : 0;
@@ -2091,7 +2196,7 @@ void ex_function(exarg_T *eap)
         j++;
       }
       if (arg[j] != NUL) {
-        emsg_funcname((char *)e_invarg2, (char_u *)arg);
+        emsg_funcname((char *)e_invarg2, arg);
       }
     }
     // Disallow using the g: dict.
@@ -2113,21 +2218,21 @@ void ex_function(exarg_T *eap)
   // find extra arguments "range", "dict", "abort" and "closure"
   for (;;) {
     p = skipwhite(p);
-    if (STRNCMP(p, "range", 5) == 0) {
+    if (strncmp(p, "range", 5) == 0) {
       flags |= FC_RANGE;
       p += 5;
-    } else if (STRNCMP(p, "dict", 4) == 0) {
+    } else if (strncmp(p, "dict", 4) == 0) {
       flags |= FC_DICT;
       p += 4;
-    } else if (STRNCMP(p, "abort", 5) == 0) {
+    } else if (strncmp(p, "abort", 5) == 0) {
       flags |= FC_ABORT;
       p += 5;
-    } else if (STRNCMP(p, "closure", 7) == 0) {
+    } else if (strncmp(p, "closure", 7) == 0) {
       flags |= FC_CLOSURE;
       p += 7;
       if (current_funccal == NULL) {
         emsg_funcname(N_("E932: Closure function should not be at top level: %s"),
-                      name == NULL ? (char_u *)"" : (char_u *)name);
+                      name == NULL ? "" : name);
         goto erret;
       }
     } else {
@@ -2151,8 +2256,8 @@ void ex_function(exarg_T *eap)
     if (!eap->skip && !eap->forceit) {
       if (fudi.fd_dict != NULL && fudi.fd_newkey == NULL) {
         emsg(_(e_funcdict));
-      } else if (name != NULL && find_func((char_u *)name) != NULL) {
-        emsg_funcname(e_funcexts, (char_u *)name);
+      } else if (name != NULL && find_func(name) != NULL) {
+        emsg_funcname(e_funcexts, name);
       }
     }
 
@@ -2191,7 +2296,7 @@ void ex_function(exarg_T *eap)
     } else {
       xfree(line_to_free);
       if (eap->getline == NULL) {
-        theline = (char *)getcmdline(':', 0L, indent, do_concat);
+        theline = getcmdline(':', 0L, indent, do_concat);
       } else {
         theline = eap->getline(':', eap->cookie, indent, do_concat);
       }
@@ -2224,7 +2329,7 @@ void ex_function(exarg_T *eap)
       // * ":let {var-name} =<< [trim] {marker}" and "{marker}"
       if (heredoc_trimmed == NULL
           || (is_heredoc && skipwhite(theline) == theline)
-          || STRNCMP(theline, heredoc_trimmed,
+          || strncmp(theline, heredoc_trimmed,
                      strlen(heredoc_trimmed)) == 0) {
         if (heredoc_trimmed == NULL) {
           p = theline;
@@ -2274,12 +2379,12 @@ void ex_function(exarg_T *eap)
 
       // Increase indent inside "if", "while", "for" and "try", decrease
       // at "end".
-      if (indent > 2 && STRNCMP(p, "end", 3) == 0) {
+      if (indent > 2 && strncmp(p, "end", 3) == 0) {
         indent -= 2;
-      } else if (STRNCMP(p, "if", 2) == 0
-                 || STRNCMP(p, "wh", 2) == 0
-                 || STRNCMP(p, "for", 3) == 0
-                 || STRNCMP(p, "try", 3) == 0) {
+      } else if (strncmp(p, "if", 2) == 0
+                 || strncmp(p, "wh", 2) == 0
+                 || strncmp(p, "for", 3) == 0
+                 || strncmp(p, "try", 3) == 0) {
         indent += 2;
       }
 
@@ -2307,7 +2412,7 @@ void ex_function(exarg_T *eap)
               && (!ASCII_ISALPHA(p[1])
                   || (p[1] == 'h' && (!ASCII_ISALPHA(p[2])
                                       || (p[2] == 'a'
-                                          && (STRNCMP(&p[3], "nge", 3) != 0
+                                          && (strncmp(&p[3], "nge", 3) != 0
                                               || !ASCII_ISALPHA(p[6])))))))
           || (p[0] == 'i'
               && (!ASCII_ISALPHA(p[1]) || (p[1] == 'n'
@@ -2358,7 +2463,7 @@ void ex_function(exarg_T *eap)
                 && (!ASCII_ISALNUM(p[2])
                     || (p[2] == 't' && !ASCII_ISALNUM(p[3]))))) {
           p = skipwhite(arg + 3);
-          if (STRNCMP(p, "trim", 4) == 0) {
+          if (strncmp(p, "trim", 4) == 0) {
             // Ignore leading white space.
             p = skipwhite(p + 4);
             heredoc_trimmed = xstrnsave(theline, (size_t)(skipwhite(theline) - theline));
@@ -2401,24 +2506,22 @@ void ex_function(exarg_T *eap)
   if (fudi.fd_dict == NULL) {
     v = find_var((const char *)name, strlen(name), &ht, false);
     if (v != NULL && v->di_tv.v_type == VAR_FUNC) {
-      emsg_funcname(N_("E707: Function name conflicts with variable: %s"),
-                    (char_u *)name);
+      emsg_funcname(N_("E707: Function name conflicts with variable: %s"), name);
       goto erret;
     }
 
-    fp = find_func((char_u *)name);
+    fp = find_func(name);
     if (fp != NULL) {
       // Function can be replaced with "function!" and when sourcing the
       // same script again, but only once.
       if (!eap->forceit
           && (fp->uf_script_ctx.sc_sid != current_sctx.sc_sid
               || fp->uf_script_ctx.sc_seq == current_sctx.sc_seq)) {
-        emsg_funcname(e_funcexts, (char_u *)name);
+        emsg_funcname(e_funcexts, name);
         goto erret;
       }
       if (fp->uf_calls > 0) {
-        emsg_funcname(N_("E127: Cannot redefine function %s: It is in use"),
-                      (char_u *)name);
+        emsg_funcname(N_("E127: Cannot redefine function %s: It is in use"), name);
         goto erret;
       }
       if (fp->uf_refcount > 1) {
@@ -2429,7 +2532,7 @@ void ex_function(exarg_T *eap)
         fp = NULL;
         overwrite = true;
       } else {
-        char_u *exp_name = fp->uf_name_exp;
+        char *exp_name = fp->uf_name_exp;
         // redefine existing function, keep the expanded name
         XFREE_CLEAR(name);
         fp->uf_name_exp = NULL;
@@ -2448,13 +2551,13 @@ void ex_function(exarg_T *eap)
       goto erret;
     }
     if (fudi.fd_di == NULL) {
-      if (var_check_lock(fudi.fd_dict->dv_lock, (const char *)eap->arg,
-                         TV_CSTRING)) {
+      if (value_check_lock(fudi.fd_dict->dv_lock, (const char *)eap->arg,
+                           TV_CSTRING)) {
         // Can't add a function to a locked dictionary
         goto erret;
       }
-    } else if (var_check_lock(fudi.fd_di->di_tv.v_lock, (const char *)eap->arg,
-                              TV_CSTRING)) {
+    } else if (value_check_lock(fudi.fd_di->di_tv.v_lock, (const char *)eap->arg,
+                                TV_CSTRING)) {
       // Can't change an existing function if it is locked
       goto erret;
     }
@@ -2469,15 +2572,15 @@ void ex_function(exarg_T *eap)
   if (fp == NULL) {
     if (fudi.fd_dict == NULL && vim_strchr(name, AUTOLOAD_CHAR) != NULL) {
       int slen, plen;
-      char_u *scriptname;
+      char *scriptname;
 
       // Check that the autoload name matches the script name.
       int j = FAIL;
       if (SOURCING_NAME != NULL) {
-        scriptname = (char_u *)autoload_name((const char *)name, strlen(name));
-        p = vim_strchr((char *)scriptname, '/');
-        plen = (int)STRLEN(p);
-        slen = (int)STRLEN(SOURCING_NAME);
+        scriptname = autoload_name(name, strlen(name));
+        p = vim_strchr(scriptname, '/');
+        plen = (int)strlen(p);
+        slen = (int)strlen(SOURCING_NAME);
         if (slen > plen && path_fnamecmp(p, SOURCING_NAME + slen - plen) == 0) {
           j = OK;
         }
@@ -2513,10 +2616,10 @@ void ex_function(exarg_T *eap)
     }
 
     // insert the new function in the function list
-    set_ufunc_name(fp, (char_u *)name);
+    set_ufunc_name(fp, name);
     if (overwrite) {
       hi = hash_find(&func_hashtab, name);
-      hi->hi_key = UF2HIKEY(fp);
+      hi->hi_key = (char *)UF2HIKEY(fp);
     } else if (hash_add(&func_hashtab, UF2HIKEY(fp)) == FAIL) {
       xfree(fp);
       goto erret;
@@ -2587,7 +2690,7 @@ bool translated_function_exists(const char *name)
   if (builtin_function(name, -1)) {
     return find_internal_func((char *)name) != NULL;
   }
-  return find_func((const char_u *)name) != NULL;
+  return find_func(name) != NULL;
 }
 
 /// Check whether function with the given name exists
@@ -2598,15 +2701,15 @@ bool translated_function_exists(const char *name)
 /// @return  true if it exists, false otherwise.
 bool function_exists(const char *const name, bool no_deref)
 {
-  const char_u *nm = (const char_u *)name;
+  const char *nm = name;
   bool n = false;
   int flag = TFN_INT | TFN_QUIET | TFN_NO_AUTOLOAD;
 
   if (no_deref) {
     flag |= TFN_NO_DEREF;
   }
-  char *const p = (char *)trans_function_name((char **)&nm, false, flag, NULL, NULL);
-  nm = (char_u *)skipwhite((char *)nm);
+  char *const p = trans_function_name((char **)&nm, false, flag, NULL, NULL);
+  nm = skipwhite(nm);
 
   // Only accept "funcname", "funcname ", "funcname (..." and
   // "funcname(...", not "funcname!...".
@@ -2622,15 +2725,17 @@ bool function_exists(const char *const name, bool no_deref)
 char *get_user_func_name(expand_T *xp, int idx)
 {
   static size_t done;
+  static int changed;
   static hashitem_T *hi;
   ufunc_T *fp;
 
   if (idx == 0) {
     done = 0;
     hi = func_hashtab.ht_array;
+    changed = func_hashtab.ht_changed;
   }
   assert(hi);
-  if (done < func_hashtab.ht_used) {
+  if (changed == func_hashtab.ht_changed && done < func_hashtab.ht_used) {
     if (done++ > 0) {
       hi++;
     }
@@ -2640,22 +2745,22 @@ char *get_user_func_name(expand_T *xp, int idx)
     fp = HI2UF(hi);
 
     if ((fp->uf_flags & FC_DICT)
-        || STRNCMP(fp->uf_name, "<lambda>", 8) == 0) {
+        || strncmp(fp->uf_name, "<lambda>", 8) == 0) {
       return "";       // don't show dict and lambda functions
     }
 
-    if (STRLEN(fp->uf_name) + 4 >= IOSIZE) {
+    if (strlen(fp->uf_name) + 4 >= IOSIZE) {
       return (char *)fp->uf_name;  // Prevent overflow.
     }
 
-    cat_func_name((char_u *)IObuff, fp);
+    cat_func_name(IObuff, fp);
     if (xp->xp_context != EXPAND_USER_FUNC) {
       STRCAT(IObuff, "(");
       if (!fp->uf_varargs && GA_EMPTY(&fp->uf_args)) {
         STRCAT(IObuff, ")");
       }
     }
-    return (char *)IObuff;
+    return IObuff;
   }
   return NULL;
 }
@@ -2664,12 +2769,12 @@ char *get_user_func_name(expand_T *xp, int idx)
 void ex_delfunction(exarg_T *eap)
 {
   ufunc_T *fp = NULL;
-  char_u *p;
-  char_u *name;
+  char *p;
+  char *name;
   funcdict_T fudi;
 
-  p = (char_u *)eap->arg;
-  name = trans_function_name((char **)&p, eap->skip, 0, &fudi, NULL);
+  p = eap->arg;
+  name = trans_function_name(&p, eap->skip, 0, &fudi, NULL);
   xfree(fudi.fd_newkey);
   if (name == NULL) {
     if (fudi.fd_dict != NULL && !eap->skip) {
@@ -2677,16 +2782,23 @@ void ex_delfunction(exarg_T *eap)
     }
     return;
   }
-  if (!ends_excmd(*skipwhite((char *)p))) {
+  if (!ends_excmd(*skipwhite(p))) {
     xfree(name);
     semsg(_(e_trailing_arg), p);
     return;
   }
-  eap->nextcmd = check_nextcmd((char *)p);
+  eap->nextcmd = check_nextcmd(p);
   if (eap->nextcmd != NULL) {
     *p = NUL;
   }
 
+  if (isdigit((uint8_t)(*name)) && fudi.fd_dict == NULL) {
+    if (!eap->skip) {
+      semsg(_(e_invarg2), eap->arg);
+    }
+    xfree(name);
+    return;
+  }
   if (!eap->skip) {
     fp = find_func(name);
   }
@@ -2737,7 +2849,7 @@ void ex_delfunction(exarg_T *eap)
 
 /// Unreference a Function: decrement the reference count and free it when it
 /// becomes zero.
-void func_unref(char_u *name)
+void func_unref(char *name)
 {
   ufunc_T *fp = NULL;
 
@@ -2746,7 +2858,7 @@ void func_unref(char_u *name)
   }
 
   fp = find_func(name);
-  if (fp == NULL && isdigit(*name)) {
+  if (fp == NULL && isdigit((uint8_t)(*name))) {
 #ifdef EXITFREE
     if (!entered_free_all_mem) {
       internal_error("func_unref()");
@@ -2779,7 +2891,7 @@ void func_ptr_unref(ufunc_T *fp)
 }
 
 /// Count a reference to a Function.
-void func_ref(char_u *name)
+void func_ref(char *name)
 {
   ufunc_T *fp;
 
@@ -2789,7 +2901,7 @@ void func_ref(char_u *name)
   fp = find_func(name);
   if (fp != NULL) {
     (fp->uf_refcount)++;
-  } else if (isdigit(*name)) {
+  } else if (isdigit((uint8_t)(*name))) {
     // Only give an error for a numbered function.
     // Fail silently, when named or lambda function isn't found.
     internal_error("func_ref()");
@@ -2833,7 +2945,7 @@ static int can_free_funccal(funccall_T *fc, int copyID)
 /// ":return [expr]"
 void ex_return(exarg_T *eap)
 {
-  char_u *arg = (char_u *)eap->arg;
+  char *arg = eap->arg;
   typval_T rettv;
   int returning = false;
 
@@ -2848,7 +2960,7 @@ void ex_return(exarg_T *eap)
 
   eap->nextcmd = NULL;
   if ((*arg != NUL && *arg != '|' && *arg != '\n')
-      && eval0((char *)arg, &rettv, &eap->nextcmd, !eap->skip) != FAIL) {
+      && eval0(arg, &rettv, &eap->nextcmd, !eap->skip) != FAIL) {
     if (!eap->skip) {
       returning = do_return(eap, false, true, &rettv);
     } else {
@@ -2871,7 +2983,7 @@ void ex_return(exarg_T *eap)
   if (returning) {
     eap->nextcmd = NULL;
   } else if (eap->nextcmd == NULL) {          // no argument
-    eap->nextcmd = check_nextcmd((char *)arg);
+    eap->nextcmd = check_nextcmd(arg);
   }
 
   if (eap->skip) {
@@ -2879,15 +2991,13 @@ void ex_return(exarg_T *eap)
   }
 }
 
-// TODO(ZyX-I): move to eval/ex_cmds
-
 /// ":1,25call func(arg1, arg2)" function call.
 void ex_call(exarg_T *eap)
 {
-  char_u *arg = (char_u *)eap->arg;
-  char_u *startarg;
-  char_u *name;
-  char_u *tofree;
+  char *arg = eap->arg;
+  char *startarg;
+  char *name;
+  char *tofree;
   int len;
   typval_T rettv;
   linenr_T lnum;
@@ -2908,7 +3018,7 @@ void ex_call(exarg_T *eap)
     return;
   }
 
-  tofree = trans_function_name((char **)&arg, false, TFN_INT, &fudi, &partial);
+  tofree = trans_function_name(&arg, false, TFN_INT, &fudi, &partial);
   if (fudi.fd_newkey != NULL) {
     // Still need to give an error message for missing key.
     semsg(_(e_dictkey), fudi.fd_newkey);
@@ -2927,13 +3037,12 @@ void ex_call(exarg_T *eap)
   // If it is the name of a variable of type VAR_FUNC or VAR_PARTIAL use its
   // contents. For VAR_PARTIAL get its partial, unless we already have one
   // from trans_function_name().
-  len = (int)STRLEN(tofree);
-  name = deref_func_name((const char *)tofree, &len,
-                         partial != NULL ? NULL : &partial, false);
+  len = (int)strlen(tofree);
+  name = deref_func_name(tofree, &len, partial != NULL ? NULL : &partial, false);
 
   // Skip white space to allow ":call func ()".  Not good, but required for
   // backward compatibility.
-  startarg = (char_u *)skipwhite((char *)arg);
+  startarg = skipwhite(arg);
   rettv.v_type = VAR_UNKNOWN;  // tv_clear() uses this.
 
   if (*startarg != '(') {
@@ -2963,7 +3072,7 @@ void ex_call(exarg_T *eap)
     funcexe.fe_evaluate = true;
     funcexe.fe_partial = partial;
     funcexe.fe_selfdict = fudi.fd_dict;
-    if (get_func_tv(name, -1, &rettv, (char **)&arg, &funcexe) == FAIL) {
+    if (get_func_tv(name, -1, &rettv, &arg, &funcexe) == FAIL) {
       failed = true;
       break;
     }
@@ -3000,7 +3109,7 @@ void ex_call(exarg_T *eap)
         semsg(_(e_trailing_arg), arg);
       }
     } else {
-      eap->nextcmd = check_nextcmd((char *)arg);
+      eap->nextcmd = check_nextcmd(arg);
     }
   }
 
@@ -3100,12 +3209,12 @@ char *get_return_cmd(void *rettv)
   }
 
   STRCPY(IObuff, ":return ");
-  STRLCPY(IObuff + 8, s, IOSIZE - 8);
+  xstrlcpy(IObuff + 8, s, IOSIZE - 8);
   if (strlen(s) + 8 >= IOSIZE) {
     STRCPY(IObuff + IOSIZE - 4, "...");
   }
   xfree(tofree);
-  return xstrdup((char *)IObuff);
+  return xstrdup(IObuff);
 }
 
 /// Get next function line.
@@ -3182,20 +3291,20 @@ int func_has_abort(void *cookie)
 /// Changes "rettv" in-place.
 void make_partial(dict_T *const selfdict, typval_T *const rettv)
 {
-  char_u *fname;
-  char_u *tofree = NULL;
+  char *fname;
+  char *tofree = NULL;
   ufunc_T *fp;
-  char_u fname_buf[FLEN_FIXED + 1];
+  char fname_buf[FLEN_FIXED + 1];
   int error;
 
   if (rettv->v_type == VAR_PARTIAL && rettv->vval.v_partial->pt_func != NULL) {
     fp = rettv->vval.v_partial->pt_func;
   } else {
     fname = rettv->v_type == VAR_FUNC || rettv->v_type == VAR_STRING
-                                      ? (char_u *)rettv->vval.v_string
-                                      : (char_u *)rettv->vval.v_partial->pt_name;
+                                      ? rettv->vval.v_string
+                                      : rettv->vval.v_partial->pt_name;
     // Translate "s:func" to the stored function name.
-    fname = (char_u *)fname_trans_sid((char *)fname, (char *)fname_buf, (char **)&tofree, &error);
+    fname = fname_trans_sid(fname, fname_buf, &tofree, &error);
     fp = find_func(fname);
     xfree(tofree);
   }
@@ -3219,7 +3328,7 @@ void make_partial(dict_T *const selfdict, typval_T *const rettv)
       // be referenced elsewhere.
       if (ret_pt->pt_name != NULL) {
         pt->pt_name = xstrdup(ret_pt->pt_name);
-        func_ref((char_u *)pt->pt_name);
+        func_ref(pt->pt_name);
       } else {
         pt->pt_func = ret_pt->pt_func;
         func_ptr_ref(pt->pt_func);
@@ -3240,7 +3349,7 @@ void make_partial(dict_T *const selfdict, typval_T *const rettv)
 }
 
 /// @return  the name of the executed function.
-char_u *func_name(void *cookie)
+char *func_name(void *cookie)
 {
   return ((funccall_T *)cookie)->func->uf_name;
 }
@@ -3527,21 +3636,21 @@ bool set_ref_in_func_args(int copyID)
 /// "ht_stack" is used to add hashtabs to be marked.  Can be NULL.
 ///
 /// @return  true if setting references failed somehow.
-bool set_ref_in_func(char_u *name, ufunc_T *fp_in, int copyID)
+bool set_ref_in_func(char *name, ufunc_T *fp_in, int copyID)
 {
   ufunc_T *fp = fp_in;
   funccall_T *fc;
   int error = FCERR_NONE;
-  char_u fname_buf[FLEN_FIXED + 1];
-  char_u *tofree = NULL;
-  char_u *fname;
+  char fname_buf[FLEN_FIXED + 1];
+  char *tofree = NULL;
+  char *fname;
   bool abort = false;
   if (name == NULL && fp_in == NULL) {
     return false;
   }
 
   if (fp_in == NULL) {
-    fname = (char_u *)fname_trans_sid((char *)name, (char *)fname_buf, (char **)&tofree, &error);
+    fname = fname_trans_sid(name, fname_buf, &tofree, &error);
     fp = find_func(fname);
   }
   if (fp != NULL) {
@@ -3554,10 +3663,10 @@ bool set_ref_in_func(char_u *name, ufunc_T *fp_in, int copyID)
 }
 
 /// Registers a luaref as a lambda.
-char_u *register_luafunc(LuaRef ref)
+char *register_luafunc(LuaRef ref)
 {
-  char_u *name = get_lambda_name();
-  ufunc_T *fp = xcalloc(1, offsetof(ufunc_T, uf_name) + STRLEN(name) + 1);
+  char *name = get_lambda_name();
+  ufunc_T *fp = xcalloc(1, offsetof(ufunc_T, uf_name) + strlen(name) + 1);
 
   fp->uf_refcount = 1;
   fp->uf_varargs = true;
diff --git a/src/nvim/eval/userfunc.h b/src/nvim/eval/userfunc.h
index 4098622a14..c8583f232c 100644
--- a/src/nvim/eval/userfunc.h
+++ b/src/nvim/eval/userfunc.h
@@ -1,8 +1,18 @@
 #ifndef NVIM_EVAL_USERFUNC_H
 #define NVIM_EVAL_USERFUNC_H
 
+#include <stdbool.h>
+#include <stddef.h>
+
 #include "nvim/eval/typval.h"
+#include "nvim/eval/typval_defs.h"
 #include "nvim/ex_cmds_defs.h"
+#include "nvim/garray.h"
+#include "nvim/hashtab.h"
+#include "nvim/pos.h"
+#include "nvim/types.h"
+
+struct funccal_entry;
 
 // From user function to hashitem and back.
 #define UF2HIKEY(fp) ((fp)->uf_name)
@@ -23,10 +33,10 @@
 #define FC_VIM9     0x400         // defined in vim9 script file
 #define FC_LUAREF  0x800          // luaref callback
 
-///< Structure used by trans_function_name()
+/// Structure used by trans_function_name()
 typedef struct {
   dict_T *fd_dict;  ///< Dictionary used.
-  char_u *fd_newkey;  ///< New key in "dict" in allocated memory.
+  char *fd_newkey;  ///< New key in "dict" in allocated memory.
   dictitem_T *fd_di;  ///< Dictionary item used.
 } funcdict_T;
 
diff --git a/src/nvim/eval/vars.c b/src/nvim/eval/vars.c
index 4d7214205d..3e593151fc 100644
--- a/src/nvim/eval/vars.c
+++ b/src/nvim/eval/vars.c
@@ -3,24 +3,43 @@
 
 // eval/vars.c: functions for dealing with variables
 
+#include <assert.h>
+#include <ctype.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+
 #include "nvim/ascii.h"
 #include "nvim/autocmd.h"
-#include "nvim/buffer.h"
+#include "nvim/buffer_defs.h"
 #include "nvim/charset.h"
 #include "nvim/drawscreen.h"
 #include "nvim/eval.h"
 #include "nvim/eval/encode.h"
 #include "nvim/eval/funcs.h"
 #include "nvim/eval/typval.h"
+#include "nvim/eval/typval_defs.h"
 #include "nvim/eval/userfunc.h"
 #include "nvim/eval/vars.h"
+#include "nvim/eval/window.h"
 #include "nvim/ex_cmds.h"
+#include "nvim/ex_cmds_defs.h"
 #include "nvim/ex_docmd.h"
 #include "nvim/ex_eval.h"
+#include "nvim/gettext.h"
+#include "nvim/globals.h"
+#include "nvim/hashtab.h"
+#include "nvim/macros.h"
+#include "nvim/memory.h"
+#include "nvim/message.h"
 #include "nvim/ops.h"
 #include "nvim/option.h"
-#include "nvim/screen.h"
+#include "nvim/os/os.h"
 #include "nvim/search.h"
+#include "nvim/strings.h"
+#include "nvim/types.h"
+#include "nvim/vim.h"
 #include "nvim/window.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
@@ -62,7 +81,7 @@ static list_T *heredoc_get(exarg_T *eap, char *cmd)
 
   // Check for the optional 'trim' word before the marker
   cmd = skipwhite(cmd);
-  if (STRNCMP(cmd, "trim", 4) == 0
+  if (strncmp(cmd, "trim", 4) == 0
       && (cmd[4] == NUL || ascii_iswhite(cmd[4]))) {
     cmd = skipwhite(cmd + 4);
 
@@ -87,7 +106,7 @@ static list_T *heredoc_get(exarg_T *eap, char *cmd)
       return NULL;
     }
     *p = NUL;
-    if (islower(*marker)) {
+    if (islower((uint8_t)(*marker))) {
       emsg(_("E221: Marker cannot start with lower case letter"));
       return NULL;
     }
@@ -110,7 +129,7 @@ static list_T *heredoc_get(exarg_T *eap, char *cmd)
     // with "trim": skip the indent matching the :let line to find the
     // marker
     if (marker_indent_len > 0
-        && STRNCMP(theline, *eap->cmdlinep, marker_indent_len) == 0) {
+        && strncmp(theline, *eap->cmdlinep, (size_t)marker_indent_len) == 0) {
       mi = marker_indent_len;
     }
     if (strcmp(marker, theline + mi) == 0) {
@@ -189,8 +208,8 @@ static void ex_let_const(exarg_T *eap, const bool is_const)
     argend--;
   }
   expr = skipwhite(argend);
-  if (*expr != '=' && !((vim_strchr("+-*/%.", *expr) != NULL
-                         && expr[1] == '=') || STRNCMP(expr, "..=", 3) == 0)) {
+  if (*expr != '=' && !((vim_strchr("+-*/%.", (uint8_t)(*expr)) != NULL
+                         && expr[1] == '=') || strncmp(expr, "..=", 3) == 0)) {
     // ":let" without "=": list variables
     if (*arg == '[') {
       emsg(_(e_invarg));
@@ -225,17 +244,19 @@ static void ex_let_const(exarg_T *eap, const bool is_const)
     op[0] = '=';
     op[1] = NUL;
     if (*expr != '=') {
-      if (vim_strchr("+-*/%.", *expr) != NULL) {
+      if (vim_strchr("+-*/%.", (uint8_t)(*expr)) != NULL) {
         op[0] = *expr;  // +=, -=, *=, /=, %= or .=
         if (expr[0] == '.' && expr[1] == '.') {  // ..=
           expr++;
         }
       }
-      expr = skipwhite(expr + 2);
+      expr += 2;
     } else {
-      expr = skipwhite(expr + 1);
+      expr += 1;
     }
 
+    expr = skipwhite(expr);
+
     if (eap->skip) {
       emsg_skip++;
     }
@@ -378,9 +399,8 @@ const char *skip_var_list(const char *arg, int *var_count, int *semicolon)
       }
     }
     return p + 1;
-  } else {
-    return skip_var_one((char *)arg);
   }
+  return skip_var_one((char *)arg);
 }
 
 /// Skip one (assignable) variable name, including @r, $VAR, &option, d.key,
@@ -539,8 +559,6 @@ static const char *list_arg_vars(exarg_T *eap, const char *arg, int *first)
   return arg;
 }
 
-// TODO(ZyX-I): move to eval/ex_cmds
-
 /// Set one item of `:let var = expr` or `:let [v1, v2] = list` to its value
 ///
 /// @param[in]  arg  Start of the variable name.
@@ -558,8 +576,6 @@ static char *ex_let_one(char *arg, typval_T *const tv, const bool copy, const bo
 {
   char *arg_end = NULL;
   int len;
-  int opt_flags;
-  char *tofree = NULL;
 
   // ":let $VAR = expr": Set environment variable.
   if (*arg == '$') {
@@ -574,18 +590,18 @@ static char *ex_let_one(char *arg, typval_T *const tv, const bool copy, const bo
     if (len == 0) {
       semsg(_(e_invarg2), name - 1);
     } else {
-      if (op != NULL && vim_strchr("+-*/%", *op) != NULL) {
+      if (op != NULL && vim_strchr("+-*/%", (uint8_t)(*op)) != NULL) {
         semsg(_(e_letwrong), op);
       } else if (endchars != NULL
-                 && vim_strchr(endchars, *skipwhite(arg)) == NULL) {
+                 && vim_strchr(endchars, (uint8_t)(*skipwhite(arg))) == NULL) {
         emsg(_(e_letunexp));
       } else if (!check_secure()) {
+        char *tofree = NULL;
         const char c1 = name[len];
         name[len] = NUL;
         const char *p = tv_get_string_chk(tv);
         if (p != NULL && op != NULL && *op == '.') {
           char *s = vim_getenv(name);
-
           if (s != NULL) {
             tofree = concat_str(s, p);
             p = (const char *)tofree;
@@ -609,10 +625,11 @@ static char *ex_let_one(char *arg, typval_T *const tv, const bool copy, const bo
       return NULL;
     }
     // Find the end of the name.
-    char *const p = (char *)find_option_end((const char **)&arg, &opt_flags);
+    int scope;
+    char *const p = (char *)find_option_end((const char **)&arg, &scope);
     if (p == NULL
         || (endchars != NULL
-            && vim_strchr(endchars, *skipwhite(p)) == NULL)) {
+            && vim_strchr(endchars, (uint8_t)(*skipwhite(p))) == NULL)) {
       emsg(_(e_letunexp));
     } else {
       varnumber_T n = 0;
@@ -621,11 +638,13 @@ static char *ex_let_one(char *arg, typval_T *const tv, const bool copy, const bo
       char *stringval = NULL;
       const char *s = NULL;
       bool failed = false;
+      uint32_t opt_p_flags;
+      char *tofree = NULL;
 
       const char c1 = *p;
       *p = NUL;
 
-      opt_type = get_option_value(arg, &numval, &stringval, opt_flags);
+      opt_type = get_option_value(arg, &numval, &stringval, &opt_p_flags, scope);
       if (opt_type == gov_bool
           || opt_type == gov_number
           || opt_type == gov_hidden_bool
@@ -634,8 +653,13 @@ static char *ex_let_one(char *arg, typval_T *const tv, const bool copy, const bo
         n = (long)tv_get_number(tv);
       }
 
-      // Avoid setting a string option to the text "v:false" or similar.
-      if (tv->v_type != VAR_BOOL && tv->v_type != VAR_SPECIAL) {
+      if ((opt_p_flags & P_FUNC) && tv_is_func(*tv)) {
+        // If the option can be set to a function reference or a lambda
+        // and the passed value is a function reference, then convert it to
+        // the name (string) of the function reference.
+        s = tofree = encode_tv2string(tv, NULL);
+      } else if (tv->v_type != VAR_BOOL && tv->v_type != VAR_SPECIAL) {
+        // Avoid setting a string option to the text "v:false" or similar.
         s = tv_get_string_chk(tv);
       }
 
@@ -672,7 +696,7 @@ static char *ex_let_one(char *arg, typval_T *const tv, const bool copy, const bo
 
       if (!failed) {
         if (opt_type != gov_string || s != NULL) {
-          char *err = set_option_value(arg, n, s, opt_flags);
+          char *err = set_option_value(arg, n, s, scope);
           arg_end = p;
           if (err != NULL) {
             emsg(_(err));
@@ -683,6 +707,7 @@ static char *ex_let_one(char *arg, typval_T *const tv, const bool copy, const bo
       }
       *p = c1;
       xfree(stringval);
+      xfree(tofree);
     }
     // ":let @r = expr": Set register contents.
   } else if (*arg == '@') {
@@ -691,10 +716,10 @@ static char *ex_let_one(char *arg, typval_T *const tv, const bool copy, const bo
       return NULL;
     }
     arg++;
-    if (op != NULL && vim_strchr("+-*/%", *op) != NULL) {
+    if (op != NULL && vim_strchr("+-*/%", (uint8_t)(*op)) != NULL) {
       semsg(_(e_letwrong), op);
     } else if (endchars != NULL
-               && vim_strchr(endchars, *skipwhite(arg + 1)) == NULL) {
+               && vim_strchr(endchars, (uint8_t)(*skipwhite(arg + 1))) == NULL) {
       emsg(_(e_letunexp));
     } else {
       char *s;
@@ -722,7 +747,7 @@ static char *ex_let_one(char *arg, typval_T *const tv, const bool copy, const bo
 
     char *const p = get_lval(arg, tv, &lv, false, false, 0, FNE_CHECK_START);
     if (p != NULL && lv.ll_name != NULL) {
-      if (endchars != NULL && vim_strchr(endchars, *skipwhite(p)) == NULL) {
+      if (endchars != NULL && vim_strchr(endchars, (uint8_t)(*skipwhite(p))) == NULL) {
         emsg(_(e_letunexp));
       } else {
         set_var_lval(&lv, p, tv, copy, is_const, op);
@@ -743,8 +768,6 @@ void ex_unlet(exarg_T *eap)
   ex_unletlock(eap, eap->arg, 0, do_unlet_var);
 }
 
-// TODO(ZyX-I): move to eval/ex_cmds
-
 /// ":lockvar" and ":unlockvar" commands
 void ex_lockvar(exarg_T *eap)
 {
@@ -761,8 +784,6 @@ void ex_lockvar(exarg_T *eap)
   ex_unletlock(eap, arg, deep, do_lock_var);
 }
 
-// TODO(ZyX-I): move to eval/ex_cmds
-
 /// Common parsing logic for :unlet, :lockvar and :unlockvar.
 ///
 /// Invokes `callback` afterwards if successful and `eap->skip == false`.
@@ -827,8 +848,6 @@ static void ex_unletlock(exarg_T *eap, char *argstart, int deep, ex_unletlock_ca
   eap->nextcmd = check_nextcmd(arg);
 }
 
-// TODO(ZyX-I): move to eval/ex_cmds
-
 /// Unlet a variable indicated by `lp`.
 ///
 /// @param[in]  lp  The lvalue.
@@ -845,7 +864,7 @@ static int do_unlet_var(lval_T *lp, char *name_end, exarg_T *eap, int deep FUNC_
   int cc;
 
   if (lp->ll_tv == NULL) {
-    cc = (char_u)(*name_end);
+    cc = (uint8_t)(*name_end);
     *name_end = NUL;
 
     // Environment variable, normal name or expanded name.
@@ -858,13 +877,13 @@ static int do_unlet_var(lval_T *lp, char *name_end, exarg_T *eap, int deep FUNC_
   } else if ((lp->ll_list != NULL
               // ll_list is not NULL when lvalue is not in a list, NULL lists
               // yield E689.
-              && var_check_lock(tv_list_locked(lp->ll_list),
-                                lp->ll_name,
-                                lp->ll_name_len))
+              && value_check_lock(tv_list_locked(lp->ll_list),
+                                  lp->ll_name,
+                                  lp->ll_name_len))
              || (lp->ll_dict != NULL
-                 && var_check_lock(lp->ll_dict->dv_lock,
-                                   lp->ll_name,
-                                   lp->ll_name_len))) {
+                 && value_check_lock(lp->ll_dict->dv_lock,
+                                     lp->ll_name,
+                                     lp->ll_name_len))) {
     return FAIL;
   } else if (lp->ll_range) {
     assert(lp->ll_list != NULL);
@@ -873,18 +892,17 @@ static int do_unlet_var(lval_T *lp, char *name_end, exarg_T *eap, int deep FUNC_
     listitem_T *last_li = first_li;
     for (;;) {
       listitem_T *const li = TV_LIST_ITEM_NEXT(lp->ll_list, lp->ll_li);
-      if (var_check_lock(TV_LIST_ITEM_TV(lp->ll_li)->v_lock,
-                         lp->ll_name,
-                         lp->ll_name_len)) {
+      if (value_check_lock(TV_LIST_ITEM_TV(lp->ll_li)->v_lock,
+                           lp->ll_name,
+                           lp->ll_name_len)) {
         return false;
       }
       lp->ll_li = li;
       lp->ll_n1++;
       if (lp->ll_li == NULL || (!lp->ll_empty2 && lp->ll_n2 < lp->ll_n1)) {
         break;
-      } else {
-        last_li = lp->ll_li;
       }
+      last_li = lp->ll_li;
     }
     tv_list_remove_items(lp->ll_list, first_li, last_li);
   } else {
@@ -919,8 +937,6 @@ static int do_unlet_var(lval_T *lp, char *name_end, exarg_T *eap, int deep FUNC_
   return ret;
 }
 
-// TODO(ZyX-I): move to eval/ex_cmds
-
 /// unlet a variable
 ///
 /// @param[in]  name  Variable name to unlet.
@@ -960,11 +976,11 @@ int do_unlet(const char *const name, const size_t name_len, const bool forceit)
       dictitem_T *const di = TV_DICT_HI2DI(hi);
       if (var_check_fixed(di->di_flags, name, TV_CSTRING)
           || var_check_ro(di->di_flags, name, TV_CSTRING)
-          || var_check_lock(d->dv_lock, name, TV_CSTRING)) {
+          || value_check_lock(d->dv_lock, name, TV_CSTRING)) {
         return FAIL;
       }
 
-      if (var_check_lock(d->dv_lock, name, TV_CSTRING)) {
+      if (value_check_lock(d->dv_lock, name, TV_CSTRING)) {
         return FAIL;
       }
 
@@ -991,8 +1007,6 @@ int do_unlet(const char *const name, const size_t name_len, const bool forceit)
   return FAIL;
 }
 
-// TODO(ZyX-I): move to eval/ex_cmds
-
 /// Lock or unlock variable indicated by `lp`.
 ///
 /// Locks if `eap->cmdidx == CMD_lockvar`, unlocks otherwise.
@@ -1009,10 +1023,6 @@ static int do_lock_var(lval_T *lp, char *name_end FUNC_ATTR_UNUSED, exarg_T *eap
   bool lock = eap->cmdidx == CMD_lockvar;
   int ret = OK;
 
-  if (deep == 0) {  // Nothing to do.
-    return OK;
-  }
-
   if (lp->ll_tv == NULL) {
     if (*lp->ll_name == '$') {
       semsg(_(e_lock_unlock), lp->ll_name);
@@ -1036,9 +1046,13 @@ static int do_lock_var(lval_T *lp, char *name_end FUNC_ATTR_UNUSED, exarg_T *eap
         } else {
           di->di_flags &= (uint8_t)(~DI_FLAGS_LOCK);
         }
-        tv_item_lock(&di->di_tv, deep, lock, false);
+        if (deep != 0) {
+          tv_item_lock(&di->di_tv, deep, lock, false);
+        }
       }
     }
+  } else if (deep == 0) {
+    // nothing to do
   } else if (lp->ll_range) {
     listitem_T *li = lp->ll_li;
 
@@ -1098,7 +1112,7 @@ int get_var_tv(const char *name, int len, typval_T *rettv, dictitem_T **dip, boo
 ///          NULL when it doesn't exist.
 ///
 /// @see  tv_get_string() for how long the pointer remains valid.
-char_u *get_var_value(const char *const name)
+char *get_var_value(const char *const name)
 {
   dictitem_T *v;
 
@@ -1106,7 +1120,7 @@ char_u *get_var_value(const char *const name)
   if (v == NULL) {
     return NULL;
   }
-  return (char_u *)tv_get_string(&v->di_tv);
+  return (char *)tv_get_string(&v->di_tv);
 }
 
 /// Clean up a list of internal variables.
@@ -1161,7 +1175,7 @@ void delete_var(hashtab_T *ht, hashitem_T *hi)
 static void list_one_var(dictitem_T *v, const char *prefix, int *first)
 {
   char *const s = encode_tv2echo(&v->di_tv, NULL);
-  list_one_var_a(prefix, (const char *)v->di_key, (ptrdiff_t)STRLEN(v->di_key),
+  list_one_var_a(prefix, (const char *)v->di_key, (ptrdiff_t)strlen((char *)v->di_key),
                  v->di_tv.v_type, (s == NULL ? "" : s), first);
   xfree(s);
 }
@@ -1257,7 +1271,7 @@ void set_var_const(const char *name, const size_t name_len, typval_T *const tv,
     v = find_var_in_scoped_ht(name, name_len, true);
   }
 
-  if (tv_is_func(*tv) && !var_check_func_name(name, v == NULL)) {
+  if (tv_is_func(*tv) && var_wrong_func_name(name, v == NULL)) {
     return;
   }
 
@@ -1268,12 +1282,18 @@ void set_var_const(const char *name, const size_t name_len, typval_T *const tv,
       return;
     }
 
-    // existing variable, need to clear the value
+    // Check in this order for backwards compatibility:
+    // - Whether the variable is read-only
+    // - Whether the variable value is locked
+    // - Whether the variable is locked
     if (var_check_ro(v->di_flags, name, name_len)
-        || var_check_lock(v->di_tv.v_lock, name, name_len)) {
+        || value_check_lock(v->di_tv.v_lock, name, name_len)
+        || var_check_lock(v->di_flags, name, name_len)) {
       return;
     }
 
+    // existing variable, need to clear the value
+
     // Handle setting internal v: variables separately where needed to
     // prevent changing the type.
     if (is_vimvarht(ht)) {
@@ -1329,7 +1349,7 @@ void set_var_const(const char *name, const size_t name_len, typval_T *const tv,
 
     v = xmalloc(sizeof(dictitem_T) + strlen(varname));
     STRCPY(v->di_key, varname);
-    if (tv_dict_add(dict, v) == FAIL) {
+    if (hash_add(ht, (char *)v->di_key) == FAIL) {
       xfree(v);
       return;
     }
@@ -1404,6 +1424,26 @@ bool var_check_ro(const int flags, const char *name, size_t name_len)
   return true;
 }
 
+/// Return true if di_flags "flags" indicates variable "name" is locked.
+/// Also give an error message.
+bool var_check_lock(const int flags, const char *name, size_t name_len)
+{
+  if (!(flags & DI_FLAGS_LOCK)) {
+    return false;
+  }
+
+  if (name_len == TV_TRANSLATE) {
+    name = _(name);
+    name_len = strlen(name);
+  } else if (name_len == TV_CSTRING) {
+    name_len = strlen(name);
+  }
+
+  semsg(_("E1122: Variable is locked: %*s"), (int)name_len, name);
+
+  return true;
+}
+
 /// Check whether variable is fixed (DI_FLAGS_FIX)
 ///
 /// Also gives an error message.
@@ -1438,37 +1478,34 @@ bool var_check_fixed(const int flags, const char *name, size_t name_len)
   return false;
 }
 
-// TODO(ZyX-I): move to eval/expressions
-
 /// Check if name is a valid name to assign funcref to
 ///
 /// @param[in]  name  Possible function/funcref name.
 /// @param[in]  new_var  True if it is a name for a variable.
 ///
-/// @return false in case of error, true in case of success. Also gives an
+/// @return false in case of success, true in case of failure. Also gives an
 ///         error message if appropriate.
-bool var_check_func_name(const char *const name, const bool new_var)
+bool var_wrong_func_name(const char *const name, const bool new_var)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT
 {
   // Allow for w: b: s: and t:.
-  if (!(vim_strchr("wbst", name[0]) != NULL && name[1] == ':')
-      && !ASCII_ISUPPER((name[0] != NUL && name[1] == ':')
-                        ? name[2] : name[0])) {
+  // Allow autoload variable.
+  if (!(vim_strchr("wbst", (uint8_t)name[0]) != NULL && name[1] == ':')
+      && !ASCII_ISUPPER((name[0] != NUL && name[1] == ':') ? name[2] : name[0])
+      && vim_strchr(name, '#') == NULL) {
     semsg(_("E704: Funcref variable name must start with a capital: %s"), name);
-    return false;
+    return true;
   }
   // Don't allow hiding a function.  When "v" is not NULL we might be
   // assigning another function to the same var, the type is checked
   // below.
   if (new_var && function_exists(name, false)) {
     semsg(_("E705: Variable name conflicts with existing function: %s"), name);
-    return false;
+    return true;
   }
-  return true;
+  return false;
 }
 
-// TODO(ZyX-I): move to eval/expressions
-
 /// Check if a variable name is valid
 ///
 /// @param[in]  varname  Variable name to check.
@@ -1643,25 +1680,27 @@ static void setwinvar(typval_T *argvars, typval_T *rettv, int off)
   const char *varname = tv_get_string_chk(&argvars[off + 1]);
   typval_T *varp = &argvars[off + 2];
 
-  if (win != NULL && varname != NULL && varp != NULL) {
-    bool need_switch_win = !(tp == curtab && win == curwin);
-    switchwin_T switchwin;
-    if (!need_switch_win || switch_win(&switchwin, win, tp, true) == OK) {
-      if (*varname == '&') {
-        set_option_from_tv(varname + 1, varp);
-      } else {
-        const size_t varname_len = strlen(varname);
-        char *const winvarname = xmalloc(varname_len + 3);
-        memcpy(winvarname, "w:", 2);
-        memcpy(winvarname + 2, varname, varname_len + 1);
-        set_var(winvarname, varname_len + 2, varp, true);
-        xfree(winvarname);
-      }
-    }
-    if (need_switch_win) {
-      restore_win(&switchwin, true);
+  if (win == NULL || varname == NULL) {
+    return;
+  }
+
+  bool need_switch_win = !(tp == curtab && win == curwin);
+  switchwin_T switchwin;
+  if (!need_switch_win || switch_win(&switchwin, win, tp, true) == OK) {
+    if (*varname == '&') {
+      set_option_from_tv(varname + 1, varp);
+    } else {
+      const size_t varname_len = strlen(varname);
+      char *const winvarname = xmalloc(varname_len + 3);
+      memcpy(winvarname, "w:", 2);
+      memcpy(winvarname + 2, varname, varname_len + 1);
+      set_var(winvarname, varname_len + 2, varp, true);
+      xfree(winvarname);
     }
   }
+  if (need_switch_win) {
+    restore_win(&switchwin, true);
+  }
 }
 
 bool var_exists(const char *var)
@@ -1744,21 +1783,23 @@ void f_settabvar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   const char *const varname = tv_get_string_chk(&argvars[1]);
   typval_T *const varp = &argvars[2];
 
-  if (varname != NULL && tp != NULL) {
-    tabpage_T *const save_curtab = curtab;
-    goto_tabpage_tp(tp, false, false);
+  if (varname == NULL || tp == NULL) {
+    return;
+  }
 
-    const size_t varname_len = strlen(varname);
-    char *const tabvarname = xmalloc(varname_len + 3);
-    memcpy(tabvarname, "t:", 2);
-    memcpy(tabvarname + 2, varname, varname_len + 1);
-    set_var(tabvarname, varname_len + 2, varp, true);
-    xfree(tabvarname);
-
-    // Restore current tabpage.
-    if (valid_tabpage(save_curtab)) {
-      goto_tabpage_tp(save_curtab, false, false);
-    }
+  tabpage_T *const save_curtab = curtab;
+  goto_tabpage_tp(tp, false, false);
+
+  const size_t varname_len = strlen(varname);
+  char *const tabvarname = xmalloc(varname_len + 3);
+  memcpy(tabvarname, "t:", 2);
+  memcpy(tabvarname + 2, varname, varname_len + 1);
+  set_var(tabvarname, varname_len + 2, varp, true);
+  xfree(tabvarname);
+
+  // Restore current tabpage.
+  if (valid_tabpage(save_curtab)) {
+    goto_tabpage_tp(save_curtab, false, false);
   }
 }
 
@@ -1785,27 +1826,29 @@ void f_setbufvar(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
   buf_T *const buf = tv_get_buf(&argvars[0], false);
   typval_T *varp = &argvars[2];
 
-  if (buf != NULL && varname != NULL) {
-    if (*varname == '&') {
-      aco_save_T aco;
+  if (buf == NULL || varname == NULL) {
+    return;
+  }
 
-      // set curbuf to be our buf, temporarily
-      aucmd_prepbuf(&aco, buf);
+  if (*varname == '&') {
+    aco_save_T aco;
 
-      set_option_from_tv(varname + 1, varp);
+    // Set curbuf to be our buf, temporarily.
+    aucmd_prepbuf(&aco, buf);
 
-      // reset notion of buffer
-      aucmd_restbuf(&aco);
-    } else {
-      const size_t varname_len = strlen(varname);
-      char *const bufvarname = xmalloc(varname_len + 3);
-      buf_T *const save_curbuf = curbuf;
-      curbuf = buf;
-      memcpy(bufvarname, "b:", 2);
-      memcpy(bufvarname + 2, varname, varname_len + 1);
-      set_var(bufvarname, varname_len + 2, varp, true);
-      xfree(bufvarname);
-      curbuf = save_curbuf;
-    }
+    set_option_from_tv(varname + 1, varp);
+
+    // reset notion of buffer
+    aucmd_restbuf(&aco);
+  } else {
+    const size_t varname_len = strlen(varname);
+    char *const bufvarname = xmalloc(varname_len + 3);
+    buf_T *const save_curbuf = curbuf;
+    curbuf = buf;
+    memcpy(bufvarname, "b:", 2);
+    memcpy(bufvarname + 2, varname, varname_len + 1);
+    set_var(bufvarname, varname_len + 2, varp, true);
+    xfree(bufvarname);
+    curbuf = save_curbuf;
   }
 }
diff --git a/src/nvim/eval/vars.h b/src/nvim/eval/vars.h
index 73efc4938a..b87c9d62cb 100644
--- a/src/nvim/eval/vars.h
+++ b/src/nvim/eval/vars.h
@@ -1,7 +1,7 @@
 #ifndef NVIM_EVAL_VARS_H
 #define NVIM_EVAL_VARS_H
 
-#include "nvim/ex_cmds_defs.h"  // For exarg_T
+#include "nvim/ex_cmds_defs.h"
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "eval/vars.h.generated.h"
diff --git a/src/nvim/eval/window.c b/src/nvim/eval/window.c
new file mode 100644
index 0000000000..f58a0c488a
--- /dev/null
+++ b/src/nvim/eval/window.c
@@ -0,0 +1,954 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
+// eval/window.c: Window related builtin functions
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "nvim/ascii.h"
+#include "nvim/autocmd.h"
+#include "nvim/buffer.h"
+#include "nvim/buffer_defs.h"
+#include "nvim/cursor.h"
+#include "nvim/eval/funcs.h"
+#include "nvim/eval/typval.h"
+#include "nvim/eval/typval_defs.h"
+#include "nvim/eval/window.h"
+#include "nvim/garray.h"
+#include "nvim/gettext.h"
+#include "nvim/globals.h"
+#include "nvim/macros.h"
+#include "nvim/memline_defs.h"
+#include "nvim/memory.h"
+#include "nvim/message.h"
+#include "nvim/move.h"
+#include "nvim/option_defs.h"
+#include "nvim/pos.h"
+#include "nvim/types.h"
+#include "nvim/vim.h"
+#include "nvim/window.h"
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "eval/window.c.generated.h"
+#endif
+
+static char *e_invalwindow = N_("E957: Invalid window number");
+static char e_cannot_resize_window_in_another_tab_page[]
+  = N_("E1308: Cannot resize a window in another tab page");
+
+static int win_getid(typval_T *argvars)
+{
+  if (argvars[0].v_type == VAR_UNKNOWN) {
+    return curwin->handle;
+  }
+  int winnr = (int)tv_get_number(&argvars[0]);
+  win_T *wp;
+  if (winnr <= 0) {
+    return 0;
+  }
+
+  if (argvars[1].v_type == VAR_UNKNOWN) {
+    wp = firstwin;
+  } else {
+    tabpage_T *tp = NULL;
+    int tabnr = (int)tv_get_number(&argvars[1]);
+    FOR_ALL_TABS(tp2) {
+      if (--tabnr == 0) {
+        tp = tp2;
+        break;
+      }
+    }
+    if (tp == NULL) {
+      return -1;
+    }
+    if (tp == curtab) {
+      wp = firstwin;
+    } else {
+      wp = tp->tp_firstwin;
+    }
+  }
+  for (; wp != NULL; wp = wp->w_next) {
+    if (--winnr == 0) {
+      return wp->handle;
+    }
+  }
+  return 0;
+}
+
+static void win_id2tabwin(typval_T *const argvars, typval_T *const rettv)
+{
+  handle_T id = (handle_T)tv_get_number(&argvars[0]);
+
+  int winnr = 1;
+  int tabnr = 1;
+  win_get_tabwin(id, &tabnr, &winnr);
+
+  list_T *const list = tv_list_alloc_ret(rettv, 2);
+  tv_list_append_number(list, tabnr);
+  tv_list_append_number(list, winnr);
+}
+
+win_T *win_id2wp(int id)
+{
+  return win_id2wp_tp(id, NULL);
+}
+
+/// Return the window and tab pointer of window "id".
+win_T *win_id2wp_tp(int id, tabpage_T **tpp)
+{
+  FOR_ALL_TAB_WINDOWS(tp, wp) {
+    if (wp->handle == id) {
+      if (tpp != NULL) {
+        *tpp = tp;
+      }
+      return wp;
+    }
+  }
+
+  return NULL;
+}
+
+static int win_id2win(typval_T *argvars)
+{
+  int nr = 1;
+  int id = (int)tv_get_number(&argvars[0]);
+
+  FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
+    if (wp->handle == id) {
+      return nr;
+    }
+    nr++;
+  }
+  return 0;
+}
+
+void win_findbuf(typval_T *argvars, list_T *list)
+{
+  int bufnr = (int)tv_get_number(&argvars[0]);
+
+  FOR_ALL_TAB_WINDOWS(tp, wp) {
+    if (wp->w_buffer->b_fnum == bufnr) {
+      tv_list_append_number(list, wp->handle);
+    }
+  }
+}
+
+/// Find window specified by "vp" in tabpage "tp".
+///
+/// @param tp  NULL for current tab page
+/// @return  current window if "vp" is number zero.
+///          NULL if not found.
+win_T *find_win_by_nr(typval_T *vp, tabpage_T *tp)
+{
+  int nr = (int)tv_get_number_chk(vp, NULL);
+
+  if (nr < 0) {
+    return NULL;
+  }
+
+  if (nr == 0) {
+    return curwin;
+  }
+
+  // This method accepts NULL as an alias for curtab.
+  if (tp == NULL) {
+    tp = curtab;
+  }
+
+  FOR_ALL_WINDOWS_IN_TAB(wp, tp) {
+    if (nr >= LOWEST_WIN_ID) {
+      if (wp->handle == nr) {
+        return wp;
+      }
+    } else if (--nr <= 0) {
+      return wp;
+    }
+  }
+  return NULL;
+}
+
+/// Find a window: When using a Window ID in any tab page, when using a number
+/// in the current tab page.
+win_T *find_win_by_nr_or_id(typval_T *vp)
+{
+  int nr = (int)tv_get_number_chk(vp, NULL);
+
+  if (nr >= LOWEST_WIN_ID) {
+    return win_id2wp((int)tv_get_number(vp));
+  }
+
+  return find_win_by_nr(vp, NULL);
+}
+
+/// Find window specified by "wvp" in tabpage "tvp".
+win_T *find_tabwin(typval_T *wvp, typval_T *tvp)
+{
+  win_T *wp = NULL;
+  tabpage_T *tp = NULL;
+
+  if (wvp->v_type != VAR_UNKNOWN) {
+    if (tvp->v_type != VAR_UNKNOWN) {
+      long n = tv_get_number(tvp);
+      if (n >= 0) {
+        tp = find_tabpage((int)n);
+      }
+    } else {
+      tp = curtab;
+    }
+
+    if (tp != NULL) {
+      wp = find_win_by_nr(wvp, tp);
+    }
+  } else {
+    wp = curwin;
+  }
+
+  return wp;
+}
+
+/// Get the layout of the given tab page for winlayout().
+static void get_framelayout(const frame_T *fr, list_T *l, bool outer)
+{
+  if (fr == NULL) {
+    return;
+  }
+
+  list_T *fr_list;
+  if (outer) {
+    // outermost call from f_winlayout()
+    fr_list = l;
+  } else {
+    fr_list = tv_list_alloc(2);
+    tv_list_append_list(l, fr_list);
+  }
+
+  if (fr->fr_layout == FR_LEAF) {
+    if (fr->fr_win != NULL) {
+      tv_list_append_string(fr_list, "leaf", -1);
+      tv_list_append_number(fr_list, fr->fr_win->handle);
+    }
+  } else {
+    tv_list_append_string(fr_list, fr->fr_layout == FR_ROW ? "row" : "col", -1);
+
+    list_T *const win_list = tv_list_alloc(kListLenUnknown);
+    tv_list_append_list(fr_list, win_list);
+    const frame_T *child = fr->fr_child;
+    while (child != NULL) {
+      get_framelayout(child, win_list, false);
+      child = child->fr_next;
+    }
+  }
+}
+
+/// Common code for tabpagewinnr() and winnr().
+static int get_winnr(tabpage_T *tp, typval_T *argvar)
+{
+  int nr = 1;
+
+  win_T *twin = (tp == curtab) ? curwin : tp->tp_curwin;
+  if (argvar->v_type != VAR_UNKNOWN) {
+    bool invalid_arg = false;
+    const char *const arg = tv_get_string_chk(argvar);
+    if (arg == NULL) {
+      nr = 0;  // Type error; errmsg already given.
+    } else if (strcmp(arg, "$") == 0) {
+      twin = (tp == curtab) ? lastwin : tp->tp_lastwin;
+    } else if (strcmp(arg, "#") == 0) {
+      twin = (tp == curtab) ? prevwin : tp->tp_prevwin;
+      if (twin == NULL) {
+        nr = 0;
+      }
+    } else {
+      // Extract the window count (if specified). e.g. winnr('3j')
+      char *endp;
+      long count = strtol((char *)arg, &endp, 10);
+      if (count <= 0) {
+        // if count is not specified, default to 1
+        count = 1;
+      }
+      if (endp != NULL && *endp != '\0') {
+        if (strequal(endp, "j")) {
+          twin = win_vert_neighbor(tp, twin, false, count);
+        } else if (strequal(endp, "k")) {
+          twin = win_vert_neighbor(tp, twin, true, count);
+        } else if (strequal(endp, "h")) {
+          twin = win_horz_neighbor(tp, twin, true, count);
+        } else if (strequal(endp, "l")) {
+          twin = win_horz_neighbor(tp, twin, false, count);
+        } else {
+          invalid_arg = true;
+        }
+      } else {
+        invalid_arg = true;
+      }
+    }
+
+    if (invalid_arg) {
+      semsg(_(e_invexpr2), arg);
+      nr = 0;
+    }
+  }
+
+  if (nr <= 0) {
+    return 0;
+  }
+
+  for (win_T *wp = (tp == curtab) ? firstwin : tp->tp_firstwin;
+       wp != twin; wp = wp->w_next) {
+    if (wp == NULL) {
+      // didn't find it in this tabpage
+      nr = 0;
+      break;
+    }
+    nr++;
+  }
+  return nr;
+}
+
+/// @return  information about a window as a dictionary.
+static dict_T *get_win_info(win_T *wp, int16_t tpnr, int16_t winnr)
+{
+  dict_T *const dict = tv_dict_alloc();
+
+  // make sure w_botline is valid
+  validate_botline(wp);
+
+  tv_dict_add_nr(dict, S_LEN("tabnr"), tpnr);
+  tv_dict_add_nr(dict, S_LEN("winnr"), winnr);
+  tv_dict_add_nr(dict, S_LEN("winid"), wp->handle);
+  tv_dict_add_nr(dict, S_LEN("height"), wp->w_height_inner);
+  tv_dict_add_nr(dict, S_LEN("winrow"), wp->w_winrow + 1);
+  tv_dict_add_nr(dict, S_LEN("topline"), wp->w_topline);
+  tv_dict_add_nr(dict, S_LEN("botline"), wp->w_botline - 1);
+  tv_dict_add_nr(dict, S_LEN("winbar"), wp->w_winbar_height);
+  tv_dict_add_nr(dict, S_LEN("width"), wp->w_width_inner);
+  tv_dict_add_nr(dict, S_LEN("bufnr"), wp->w_buffer->b_fnum);
+  tv_dict_add_nr(dict, S_LEN("wincol"), wp->w_wincol + 1);
+  tv_dict_add_nr(dict, S_LEN("textoff"), win_col_off(wp));
+  tv_dict_add_nr(dict, S_LEN("terminal"), bt_terminal(wp->w_buffer));
+  tv_dict_add_nr(dict, S_LEN("quickfix"), bt_quickfix(wp->w_buffer));
+  tv_dict_add_nr(dict, S_LEN("loclist"),
+                 (bt_quickfix(wp->w_buffer) && wp->w_llist_ref != NULL));
+
+  // Add a reference to window variables
+  tv_dict_add_dict(dict, S_LEN("variables"), wp->w_vars);
+
+  return dict;
+}
+
+/// @return  information (variables, options, etc.) about a tab page
+///          as a dictionary.
+static dict_T *get_tabpage_info(tabpage_T *tp, int tp_idx)
+{
+  dict_T *const dict = tv_dict_alloc();
+
+  tv_dict_add_nr(dict, S_LEN("tabnr"), tp_idx);
+
+  list_T *const l = tv_list_alloc(kListLenMayKnow);
+  FOR_ALL_WINDOWS_IN_TAB(wp, tp) {
+    tv_list_append_number(l, (varnumber_T)wp->handle);
+  }
+  tv_dict_add_list(dict, S_LEN("windows"), l);
+
+  // Make a reference to tabpage variables
+  tv_dict_add_dict(dict, S_LEN("variables"), tp->tp_vars);
+
+  return dict;
+}
+
+/// "gettabinfo()" function
+void f_gettabinfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  tabpage_T *tparg = NULL;
+
+  tv_list_alloc_ret(rettv, (argvars[0].v_type == VAR_UNKNOWN
+                            ? 1
+                            : kListLenMayKnow));
+
+  if (argvars[0].v_type != VAR_UNKNOWN) {
+    // Information about one tab page
+    tparg = find_tabpage((int)tv_get_number_chk(&argvars[0], NULL));
+    if (tparg == NULL) {
+      return;
+    }
+  }
+
+  // Get information about a specific tab page or all tab pages
+  int tpnr = 0;
+  FOR_ALL_TABS(tp) {
+    tpnr++;
+    if (tparg != NULL && tp != tparg) {
+      continue;
+    }
+    dict_T *const d = get_tabpage_info(tp, tpnr);
+    tv_list_append_dict(rettv->vval.v_list, d);
+    if (tparg != NULL) {
+      return;
+    }
+  }
+}
+
+/// "getwininfo()" function
+void f_getwininfo(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  win_T *wparg = NULL;
+
+  tv_list_alloc_ret(rettv, kListLenMayKnow);
+
+  if (argvars[0].v_type != VAR_UNKNOWN) {
+    wparg = win_id2wp((int)tv_get_number(&argvars[0]));
+    if (wparg == NULL) {
+      return;
+    }
+  }
+
+  // Collect information about either all the windows across all the tab
+  // pages or one particular window.
+  int16_t tabnr = 0;
+  FOR_ALL_TABS(tp) {
+    tabnr++;
+    int16_t winnr = 0;
+    FOR_ALL_WINDOWS_IN_TAB(wp, tp) {
+      winnr++;
+      if (wparg != NULL && wp != wparg) {
+        continue;
+      }
+      dict_T *const d = get_win_info(wp, tabnr, winnr);
+      tv_list_append_dict(rettv->vval.v_list, d);
+      if (wparg != NULL) {
+        // found information about a specific window
+        return;
+      }
+    }
+  }
+}
+
+/// "getwinpos({timeout})" function
+void f_getwinpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  tv_list_alloc_ret(rettv, 2);
+  tv_list_append_number(rettv->vval.v_list, -1);
+  tv_list_append_number(rettv->vval.v_list, -1);
+}
+
+/// "getwinposx()" function
+void f_getwinposx(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  rettv->vval.v_number = -1;
+}
+
+/// "getwinposy()" function
+void f_getwinposy(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  rettv->vval.v_number = -1;
+}
+
+/// "tabpagenr()" function
+void f_tabpagenr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  int nr = 1;
+
+  if (argvars[0].v_type != VAR_UNKNOWN) {
+    const char *const arg = tv_get_string_chk(&argvars[0]);
+    nr = 0;
+    if (arg != NULL) {
+      if (strcmp(arg, "$") == 0) {
+        nr = tabpage_index(NULL) - 1;
+      } else if (strcmp(arg, "#") == 0) {
+        nr = valid_tabpage(lastused_tabpage) ? tabpage_index(lastused_tabpage) : 0;
+      } else {
+        semsg(_(e_invexpr2), arg);
+      }
+    }
+  } else {
+    nr = tabpage_index(curtab);
+  }
+  rettv->vval.v_number = nr;
+}
+
+/// "tabpagewinnr()" function
+void f_tabpagewinnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  int nr = 1;
+  tabpage_T *const tp = find_tabpage((int)tv_get_number(&argvars[0]));
+  if (tp == NULL) {
+    nr = 0;
+  } else {
+    nr = get_winnr(tp, &argvars[1]);
+  }
+  rettv->vval.v_number = nr;
+}
+
+/// "win_execute(win_id, command)" function
+void f_win_execute(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  // Return an empty string if something fails.
+  rettv->v_type = VAR_STRING;
+  rettv->vval.v_string = NULL;
+
+  int id = (int)tv_get_number(argvars);
+  tabpage_T *tp;
+  win_T *wp = win_id2wp_tp(id, &tp);
+  if (wp == NULL || tp == NULL) {
+    return;
+  }
+
+  WIN_EXECUTE(wp, tp, execute_common(argvars, rettv, 1));
+}
+
+/// "win_findbuf()" function
+void f_win_findbuf(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  tv_list_alloc_ret(rettv, kListLenMayKnow);
+  win_findbuf(argvars, rettv->vval.v_list);
+}
+
+/// "win_getid()" function
+void f_win_getid(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  rettv->vval.v_number = win_getid(argvars);
+}
+
+/// "win_gotoid()" function
+void f_win_gotoid(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  int id = (int)tv_get_number(&argvars[0]);
+
+  if (cmdwin_type != 0) {
+    emsg(_(e_cmdwin));
+    return;
+  }
+  FOR_ALL_TAB_WINDOWS(tp, wp) {
+    if (wp->handle == id) {
+      goto_tabpage_win(tp, wp);
+      rettv->vval.v_number = 1;
+      return;
+    }
+  }
+}
+
+/// "win_id2tabwin()" function
+void f_win_id2tabwin(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  win_id2tabwin(argvars, rettv);
+}
+
+/// "win_id2win()" function
+void f_win_id2win(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  rettv->vval.v_number = win_id2win(argvars);
+}
+
+/// "win_move_separator()" function
+void f_win_move_separator(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  rettv->vval.v_number = false;
+
+  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
+  if (wp == NULL || wp->w_floating) {
+    return;
+  }
+  if (!win_valid(wp)) {
+    emsg(_(e_cannot_resize_window_in_another_tab_page));
+    return;
+  }
+
+  int offset = (int)tv_get_number(&argvars[1]);
+  win_drag_vsep_line(wp, offset);
+  rettv->vval.v_number = true;
+}
+
+/// "win_move_statusline()" function
+void f_win_move_statusline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  win_T *wp;
+  int offset;
+
+  rettv->vval.v_number = false;
+
+  wp = find_win_by_nr_or_id(&argvars[0]);
+  if (wp == NULL || wp->w_floating) {
+    return;
+  }
+  if (!win_valid(wp)) {
+    emsg(_(e_cannot_resize_window_in_another_tab_page));
+    return;
+  }
+
+  offset = (int)tv_get_number(&argvars[1]);
+  win_drag_status_line(wp, offset);
+  rettv->vval.v_number = true;
+}
+
+/// "win_screenpos()" function
+void f_win_screenpos(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  tv_list_alloc_ret(rettv, 2);
+  const win_T *const wp = find_win_by_nr_or_id(&argvars[0]);
+  tv_list_append_number(rettv->vval.v_list, wp == NULL ? 0 : wp->w_winrow + 1);
+  tv_list_append_number(rettv->vval.v_list, wp == NULL ? 0 : wp->w_wincol + 1);
+}
+
+/// Move the window wp into a new split of targetwin in a given direction
+static void win_move_into_split(win_T *wp, win_T *targetwin, int size, int flags)
+{
+  int height = wp->w_height;
+  win_T *oldwin = curwin;
+
+  if (wp == targetwin || is_aucmd_win(wp)) {
+    return;
+  }
+
+  // Jump to the target window
+  if (curwin != targetwin) {
+    win_goto(targetwin);
+  }
+
+  // Remove the old window and frame from the tree of frames
+  int dir;
+  (void)winframe_remove(wp, &dir, NULL);
+  win_remove(wp, NULL);
+  last_status(false);     // may need to remove last status line
+  (void)win_comp_pos();   // recompute window positions
+
+  // Split a window on the desired side and put the old window there
+  (void)win_split_ins(size, flags, wp, dir);
+
+  // If splitting horizontally, try to preserve height
+  if (size == 0 && !(flags & WSP_VERT)) {
+    win_setheight_win(height, wp);
+    if (p_ea) {
+      win_equal(wp, true, 'v');
+    }
+  }
+
+  if (oldwin != curwin) {
+    win_goto(oldwin);
+  }
+}
+
+/// "win_splitmove()" function
+void f_win_splitmove(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
+  win_T *targetwin = find_win_by_nr_or_id(&argvars[1]);
+
+  if (wp == NULL || targetwin == NULL || wp == targetwin
+      || !win_valid(wp) || !win_valid(targetwin)
+      || win_valid_floating(wp) || win_valid_floating(targetwin)) {
+    emsg(_(e_invalwindow));
+    rettv->vval.v_number = -1;
+    return;
+  }
+
+  int flags = 0, size = 0;
+
+  if (argvars[2].v_type != VAR_UNKNOWN) {
+    dict_T *d;
+    dictitem_T *di;
+
+    if (argvars[2].v_type != VAR_DICT || argvars[2].vval.v_dict == NULL) {
+      emsg(_(e_invarg));
+      return;
+    }
+
+    d = argvars[2].vval.v_dict;
+    if (tv_dict_get_number(d, "vertical")) {
+      flags |= WSP_VERT;
+    }
+    if ((di = tv_dict_find(d, "rightbelow", -1)) != NULL) {
+      flags |= tv_get_number(&di->di_tv) ? WSP_BELOW : WSP_ABOVE;
+    }
+    size = (int)tv_dict_get_number(d, "size");
+  }
+
+  win_move_into_split(wp, targetwin, size, flags);
+}
+
+/// "win_gettype(nr)" function
+void f_win_gettype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  win_T *wp = curwin;
+
+  rettv->v_type = VAR_STRING;
+  rettv->vval.v_string = NULL;
+  if (argvars[0].v_type != VAR_UNKNOWN) {
+    wp = find_win_by_nr_or_id(&argvars[0]);
+    if (wp == NULL) {
+      rettv->vval.v_string = xstrdup("unknown");
+      return;
+    }
+  }
+  if (is_aucmd_win(wp)) {
+    rettv->vval.v_string = xstrdup("autocmd");
+  } else if (wp->w_p_pvw) {
+    rettv->vval.v_string = xstrdup("preview");
+  } else if (wp->w_floating) {
+    rettv->vval.v_string = xstrdup("popup");
+  } else if (wp == curwin && cmdwin_type != 0) {
+    rettv->vval.v_string = xstrdup("command");
+  } else if (bt_quickfix(wp->w_buffer)) {
+    rettv->vval.v_string = xstrdup((wp->w_llist_ref != NULL ? "loclist" : "quickfix"));
+  }
+}
+
+/// "getcmdwintype()" function
+void f_getcmdwintype(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  rettv->v_type = VAR_STRING;
+  rettv->vval.v_string = NULL;
+  rettv->vval.v_string = xmallocz(1);
+  rettv->vval.v_string[0] = (char)cmdwin_type;
+}
+
+/// "winbufnr(nr)" function
+void f_winbufnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
+  if (wp == NULL) {
+    rettv->vval.v_number = -1;
+  } else {
+    rettv->vval.v_number = wp->w_buffer->b_fnum;
+  }
+}
+
+/// "wincol()" function
+void f_wincol(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  validate_cursor();
+  rettv->vval.v_number = curwin->w_wcol + 1;
+}
+
+/// "winheight(nr)" function
+void f_winheight(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
+  if (wp == NULL) {
+    rettv->vval.v_number = -1;
+  } else {
+    rettv->vval.v_number = wp->w_height_inner;
+  }
+}
+
+/// "winlayout()" function
+void f_winlayout(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  tabpage_T *tp;
+
+  tv_list_alloc_ret(rettv, 2);
+
+  if (argvars[0].v_type == VAR_UNKNOWN) {
+    tp = curtab;
+  } else {
+    tp = find_tabpage((int)tv_get_number(&argvars[0]));
+    if (tp == NULL) {
+      return;
+    }
+  }
+
+  get_framelayout(tp->tp_topframe, rettv->vval.v_list, true);
+}
+
+/// "winline()" function
+void f_winline(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  validate_cursor();
+  rettv->vval.v_number = curwin->w_wrow + 1;
+}
+
+/// "winnr()" function
+void f_winnr(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  rettv->vval.v_number = get_winnr(curtab, &argvars[0]);
+}
+
+/// "winrestcmd()" function
+void f_winrestcmd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  char buf[50];
+
+  garray_T ga;
+  ga_init(&ga, (int)sizeof(char), 70);
+
+  // Do this twice to handle some window layouts properly.
+  for (int i = 0; i < 2; i++) {
+    int winnr = 1;
+    FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
+      snprintf(buf, sizeof(buf), "%dresize %d|", winnr,
+               wp->w_height);
+      ga_concat(&ga, buf);
+      snprintf(buf, sizeof(buf), "vert %dresize %d|", winnr,
+               wp->w_width);
+      ga_concat(&ga, buf);
+      winnr++;
+    }
+  }
+  ga_append(&ga, NUL);
+
+  rettv->vval.v_string = ga.ga_data;
+  rettv->v_type = VAR_STRING;
+}
+
+/// "winrestview()" function
+void f_winrestview(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  dict_T *dict = argvars[0].vval.v_dict;
+
+  if (argvars[0].v_type != VAR_DICT || dict == NULL) {
+    emsg(_(e_invarg));
+  } else {
+    dictitem_T *di;
+    if ((di = tv_dict_find(dict, S_LEN("lnum"))) != NULL) {
+      curwin->w_cursor.lnum = (linenr_T)tv_get_number(&di->di_tv);
+    }
+    if ((di = tv_dict_find(dict, S_LEN("col"))) != NULL) {
+      curwin->w_cursor.col = (colnr_T)tv_get_number(&di->di_tv);
+    }
+    if ((di = tv_dict_find(dict, S_LEN("coladd"))) != NULL) {
+      curwin->w_cursor.coladd = (colnr_T)tv_get_number(&di->di_tv);
+    }
+    if ((di = tv_dict_find(dict, S_LEN("curswant"))) != NULL) {
+      curwin->w_curswant = (colnr_T)tv_get_number(&di->di_tv);
+      curwin->w_set_curswant = false;
+    }
+    if ((di = tv_dict_find(dict, S_LEN("topline"))) != NULL) {
+      set_topline(curwin, (linenr_T)tv_get_number(&di->di_tv));
+    }
+    if ((di = tv_dict_find(dict, S_LEN("topfill"))) != NULL) {
+      curwin->w_topfill = (int)tv_get_number(&di->di_tv);
+    }
+    if ((di = tv_dict_find(dict, S_LEN("leftcol"))) != NULL) {
+      curwin->w_leftcol = (colnr_T)tv_get_number(&di->di_tv);
+    }
+    if ((di = tv_dict_find(dict, S_LEN("skipcol"))) != NULL) {
+      curwin->w_skipcol = (colnr_T)tv_get_number(&di->di_tv);
+    }
+
+    check_cursor();
+    win_new_height(curwin, curwin->w_height);
+    win_new_width(curwin, curwin->w_width);
+    changed_window_setting();
+
+    if (curwin->w_topline <= 0) {
+      curwin->w_topline = 1;
+    }
+    if (curwin->w_topline > curbuf->b_ml.ml_line_count) {
+      curwin->w_topline = curbuf->b_ml.ml_line_count;
+    }
+    check_topfill(curwin, true);
+  }
+}
+
+/// "winsaveview()" function
+void f_winsaveview(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  tv_dict_alloc_ret(rettv);
+  dict_T *dict = rettv->vval.v_dict;
+
+  tv_dict_add_nr(dict, S_LEN("lnum"), (varnumber_T)curwin->w_cursor.lnum);
+  tv_dict_add_nr(dict, S_LEN("col"), (varnumber_T)curwin->w_cursor.col);
+  tv_dict_add_nr(dict, S_LEN("coladd"), (varnumber_T)curwin->w_cursor.coladd);
+  update_curswant();
+  tv_dict_add_nr(dict, S_LEN("curswant"), (varnumber_T)curwin->w_curswant);
+
+  tv_dict_add_nr(dict, S_LEN("topline"), (varnumber_T)curwin->w_topline);
+  tv_dict_add_nr(dict, S_LEN("topfill"), (varnumber_T)curwin->w_topfill);
+  tv_dict_add_nr(dict, S_LEN("leftcol"), (varnumber_T)curwin->w_leftcol);
+  tv_dict_add_nr(dict, S_LEN("skipcol"), (varnumber_T)curwin->w_skipcol);
+}
+
+/// "winwidth(nr)" function
+void f_winwidth(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
+{
+  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
+  if (wp == NULL) {
+    rettv->vval.v_number = -1;
+  } else {
+    rettv->vval.v_number = wp->w_width_inner;
+  }
+}
+
+/// Set "win" to be the curwin and "tp" to be the current tab page.
+/// restore_win() MUST be called to undo, also when FAIL is returned.
+/// No autocommands will be executed until restore_win() is called.
+///
+/// @param no_display  if true the display won't be affected, no redraw is
+///                    triggered, another tabpage access is limited.
+///
+/// @return FAIL if switching to "win" failed.
+int switch_win(switchwin_T *switchwin, win_T *win, tabpage_T *tp, bool no_display)
+{
+  block_autocmds();
+  return switch_win_noblock(switchwin, win, tp, no_display);
+}
+
+// As switch_win() but without blocking autocommands.
+int switch_win_noblock(switchwin_T *switchwin, win_T *win, tabpage_T *tp, bool no_display)
+{
+  CLEAR_POINTER(switchwin);
+  switchwin->sw_curwin = curwin;
+  if (win == curwin) {
+    switchwin->sw_same_win = true;
+  } else {
+    // Disable Visual selection, because redrawing may fail.
+    switchwin->sw_visual_active = VIsual_active;
+    VIsual_active = false;
+  }
+
+  if (tp != NULL) {
+    switchwin->sw_curtab = curtab;
+    if (no_display) {
+      curtab->tp_firstwin = firstwin;
+      curtab->tp_lastwin = lastwin;
+      curtab = tp;
+      firstwin = curtab->tp_firstwin;
+      lastwin = curtab->tp_lastwin;
+    } else {
+      goto_tabpage_tp(tp, false, false);
+    }
+  }
+  if (!win_valid(win)) {
+    return FAIL;
+  }
+  curwin = win;
+  curbuf = curwin->w_buffer;
+  return OK;
+}
+
+// Restore current tabpage and window saved by switch_win(), if still valid.
+// When "no_display" is true the display won't be affected, no redraw is
+// triggered.
+void restore_win(switchwin_T *switchwin, bool no_display)
+{
+  restore_win_noblock(switchwin, no_display);
+  unblock_autocmds();
+}
+
+// As restore_win() but without unblocking autocommands.
+void restore_win_noblock(switchwin_T *switchwin, bool no_display)
+{
+  if (switchwin->sw_curtab != NULL && valid_tabpage(switchwin->sw_curtab)) {
+    if (no_display) {
+      curtab->tp_firstwin = firstwin;
+      curtab->tp_lastwin = lastwin;
+      curtab = switchwin->sw_curtab;
+      firstwin = curtab->tp_firstwin;
+      lastwin = curtab->tp_lastwin;
+    } else {
+      goto_tabpage_tp(switchwin->sw_curtab, false, false);
+    }
+  }
+
+  if (!switchwin->sw_same_win) {
+    VIsual_active = switchwin->sw_visual_active;
+  }
+
+  if (win_valid(switchwin->sw_curwin)) {
+    curwin = switchwin->sw_curwin;
+    curbuf = curwin->w_buffer;
+  }
+}
diff --git a/src/nvim/eval/window.h b/src/nvim/eval/window.h
new file mode 100644
index 0000000000..995f0a55a9
--- /dev/null
+++ b/src/nvim/eval/window.h
@@ -0,0 +1,78 @@
+#ifndef NVIM_EVAL_WINDOW_H
+#define NVIM_EVAL_WINDOW_H
+
+#include <stdbool.h>
+#include <string.h>
+
+#include "nvim/buffer.h"
+#include "nvim/buffer_defs.h"
+#include "nvim/cursor.h"
+#include "nvim/eval/typval_defs.h"
+#include "nvim/globals.h"
+#include "nvim/mark.h"
+#include "nvim/option_defs.h"
+#include "nvim/os/os.h"
+#include "nvim/pos.h"
+#include "nvim/vim.h"
+#include "nvim/window.h"
+
+/// Structure used by switch_win() to pass values to restore_win()
+typedef struct {
+  win_T *sw_curwin;
+  tabpage_T *sw_curtab;
+  bool sw_same_win;  ///< VIsual_active was not reset
+  bool sw_visual_active;
+} switchwin_T;
+
+/// Execute a block of code in the context of window `wp` in tabpage `tp`.
+/// Ensures the status line is redrawn and cursor position is valid if it is moved.
+#define WIN_EXECUTE(wp, tp, block) \
+  do { \
+    win_T *const wp_ = (wp); \
+    const pos_T curpos_ = wp_->w_cursor; \
+    char cwd_[MAXPATHL]; \
+    char autocwd_[MAXPATHL]; \
+    bool apply_acd_ = false; \
+    int cwd_status_ = FAIL; \
+    /* Getting and setting directory can be slow on some systems, only do */ \
+    /* this when the current or target window/tab have a local directory or */ \
+    /* 'acd' is set. */ \
+    if (curwin != wp \
+        && (curwin->w_localdir != NULL || wp->w_localdir != NULL \
+            || (curtab != tp && (curtab->tp_localdir != NULL || tp->tp_localdir != NULL)) \
+            || p_acd)) { \
+      cwd_status_ = os_dirname(cwd_, MAXPATHL); \
+    } \
+    /* If 'acd' is set, check we are using that directory.  If yes, then */ \
+    /* apply 'acd' afterwards, otherwise restore the current directory. */ \
+    if (cwd_status_ == OK && p_acd) { \
+      do_autochdir(); \
+      apply_acd_ = os_dirname(autocwd_, MAXPATHL) == OK && strcmp(cwd_, autocwd_) == 0; \
+    } \
+    switchwin_T switchwin_; \
+    if (switch_win_noblock(&switchwin_, wp_, (tp), true) == OK) { \
+      check_cursor(); \
+      block; \
+    } \
+    restore_win_noblock(&switchwin_, true); \
+    if (apply_acd_) { \
+      do_autochdir(); \
+    } else if (cwd_status_ == OK) { \
+      os_chdir(cwd_); \
+    } \
+    /* Update the status line if the cursor moved. */ \
+    if (win_valid(wp_) && !equalpos(curpos_, wp_->w_cursor)) { \
+      wp_->w_redr_status = true; \
+    } \
+    /* In case the command moved the cursor or changed the Visual area, */ \
+    /* check it is valid. */ \
+    check_cursor(); \
+    if (VIsual_active) { \
+      check_pos(curbuf, &VIsual); \
+    } \
+  } while (false)
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "eval/window.h.generated.h"
+#endif
+#endif  // NVIM_EVAL_WINDOW_H