refactor: reduce number of explicit char casts (#16077)

* refactor: reduce number of explicit char casts

27 files changed, 151 insertions, 167 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index c1374ff00e..3103905819 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -71,7 +71,7 @@ Dictionary nvim_get_hl_by_name(String name, Boolean rgb, Error *err)
   FUNC_API_SINCE(3)
 {
   Dictionary result = ARRAY_DICT_INIT;
-  int id = syn_name2id((const char_u *)name.data);
+  int id = syn_name2id(name.data);
 
   if (id == 0) {
     api_set_error(err, kErrorTypeException, "Invalid highlight name: %s",
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index e9d89c2f91..88938d5099 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -3130,7 +3130,7 @@ void fileinfo(int fullname, int shorthelp, int dont_truncate)
       //   before redrawing).
       // - When the screen was scrolled but there is no wait-return
       //   prompt.
-      set_keep_msg((char_u *)p, 0);
+      set_keep_msg(p, 0);
     }
   }
 
@@ -3429,7 +3429,7 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
   static int *stl_separator_locations = NULL;
 
 #define TMPLEN 70
-  char_u buf_tmp[TMPLEN];
+  char buf_tmp[TMPLEN];
   char_u win_tmp[TMPLEN];
   char_u *usefmt = fmt;
   const int save_must_redraw = must_redraw;
@@ -3856,7 +3856,7 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
     bool itemisflag = false;
     bool fillable = true;
     long num = -1;
-    char_u *str = NULL;
+    char *str = NULL;
     switch (opt) {
     case STL_FILEPATH:
     case STL_FULLPATH:
@@ -3873,9 +3873,9 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
       }
       trans_characters(NameBuff, MAXPATHL);
       if (opt != STL_FILENAME) {
-        str = NameBuff;
+        str = (char *)NameBuff;
       } else {
-        str = path_tail(NameBuff);
+        str = (char *)path_tail(NameBuff);
       }
       break;
     case STL_VIM_EXPR:     // '{'
@@ -3912,8 +3912,8 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
       // { Evaluate the expression
 
       // Store the current buffer number as a string variable
-      vim_snprintf((char *)buf_tmp, sizeof(buf_tmp), "%d", curbuf->b_fnum);
-      set_internal_string_var("g:actual_curbuf", buf_tmp);
+      vim_snprintf(buf_tmp, sizeof(buf_tmp), "%d", curbuf->b_fnum);
+      set_internal_string_var("g:actual_curbuf", (char_u *)buf_tmp);
       vim_snprintf((char *)win_tmp, sizeof(win_tmp), "%d", curwin->handle);
       set_internal_string_var("g:actual_curwin", win_tmp);
 
@@ -3928,7 +3928,7 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
       }
 
       // Note: The result stored in `t` is unused.
-      str = eval_to_string_safe(out_p, &t, use_sandbox);
+      str = (char *)eval_to_string_safe(out_p, &t, use_sandbox);
 
       curwin = save_curwin;
       curbuf = save_curbuf;
@@ -3943,8 +3943,8 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
       // Check if the evaluated result is a number.
       // If so, convert the number to an int and free the string.
       if (str != NULL && *str != 0) {
-        if (*skipdigits(str) == NUL) {
-          num = atoi((char *)str);
+        if (*skipdigits((char_u *)str) == NUL) {
+          num = atoi(str);
           XFREE_CLEAR(str);
           itemisflag = false;
         }
@@ -3957,8 +3957,8 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
           && strchr((const char *)str, '%') != NULL
           && evaldepth < MAX_STL_EVAL_DEPTH) {
         size_t parsed_usefmt = (size_t)(block_start - usefmt);
-        size_t str_length = strlen((const char *)str);
-        size_t fmt_length = strlen((const char *)fmt_p);
+        size_t str_length = STRLEN(str);
+        size_t fmt_length = STRLEN(fmt_p);
         size_t new_fmt_len = parsed_usefmt
                              + str_length + fmt_length + 3;
         char_u *new_fmt = (char_u *)xmalloc(new_fmt_len * sizeof(char_u));
@@ -4029,7 +4029,7 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
       // Store the position percentage in our temporary buffer.
       // Note: We cannot store the value in `num` because
       //       `get_rel_pos` can return a named position. Ex: "Top"
-      get_rel_pos(wp, buf_tmp, TMPLEN);
+      get_rel_pos(wp, (char_u *)buf_tmp, TMPLEN);
       str = buf_tmp;
       break;
 
@@ -4044,14 +4044,14 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
 
       // Note: The call will only return true if it actually
       //       appended data to the `buf_tmp` buffer.
-      if (append_arg_number(wp, buf_tmp, (int)sizeof(buf_tmp), false)) {
+      if (append_arg_number(wp, (char_u *)buf_tmp, (int)sizeof(buf_tmp), false)) {
         str = buf_tmp;
       }
       break;
 
     case STL_KEYMAP:
       fillable = false;
-      if (get_keymap_str(wp, (char_u *)"<%s>", buf_tmp, TMPLEN)) {
+      if (get_keymap_str(wp, (char_u *)"<%s>", (char_u *)buf_tmp, TMPLEN)) {
         str = buf_tmp;
       }
       break;
@@ -4090,7 +4090,7 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
     case STL_ROFLAG_ALT:
       itemisflag = true;
       if (wp->w_buffer->b_p_ro) {
-        str = (char_u *)((opt == STL_ROFLAG_ALT) ? ",RO" : _("[RO]"));
+        str = (opt == STL_ROFLAG_ALT) ? ",RO" : _("[RO]");
       }
       break;
 
@@ -4098,8 +4098,7 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
     case STL_HELPFLAG_ALT:
       itemisflag = true;
       if (wp->w_buffer->b_help) {
-        str = (char_u *)((opt == STL_HELPFLAG_ALT) ? ",HLP"
-                                                   : _("[Help]"));
+        str = (opt == STL_HELPFLAG_ALT) ? ",HLP" : _("[Help]");
       }
       break;
 
@@ -4109,7 +4108,7 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
       // (including the brackets and null terminating character)
       if (*wp->w_buffer->b_p_ft != NUL
           && STRLEN(wp->w_buffer->b_p_ft) < TMPLEN - 3) {
-        vim_snprintf((char *)buf_tmp, sizeof(buf_tmp), "[%s]",
+        vim_snprintf(buf_tmp, sizeof(buf_tmp), "[%s]",
                      wp->w_buffer->b_p_ft);
         str = buf_tmp;
       }
@@ -4122,10 +4121,10 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
       // (including the comma and null terminating character)
       if (*wp->w_buffer->b_p_ft != NUL
           && STRLEN(wp->w_buffer->b_p_ft) < TMPLEN - 2) {
-        vim_snprintf((char *)buf_tmp, sizeof(buf_tmp), ",%s",
+        vim_snprintf(buf_tmp, sizeof(buf_tmp), ",%s",
                      wp->w_buffer->b_p_ft);
         // Uppercase the file extension
-        for (char_u *t = buf_tmp; *t != 0; t++) {
+        for (char_u *t = (char_u *)buf_tmp; *t != 0; t++) {
           *t = (char_u)TOUPPER_LOC(*t);
         }
         str = buf_tmp;
@@ -4135,16 +4134,13 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
     case STL_PREVIEWFLAG_ALT:
       itemisflag = true;
       if (wp->w_p_pvw) {
-        str = (char_u *)((opt == STL_PREVIEWFLAG_ALT) ? ",PRV"
-                                                      : _("[Preview]"));
+        str = (opt == STL_PREVIEWFLAG_ALT) ? ",PRV" : _("[Preview]");
       }
       break;
 
     case STL_QUICKFIX:
       if (bt_quickfix(wp->w_buffer)) {
-        str = (char_u *)(wp->w_llist_ref
-                         ? _(msg_loclist)
-                         : _(msg_qflist));
+        str = wp->w_llist_ref ? _(msg_loclist) : _(msg_qflist);
       }
       break;
 
@@ -4155,17 +4151,17 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
               + bufIsChanged(wp->w_buffer) * 2
               + (!MODIFIABLE(wp->w_buffer)) * 4) {
       case 2:
-        str = (char_u *)"[+]"; break;
+        str = "[+]"; break;
       case 3:
-        str = (char_u *)",+"; break;
+        str = ",+"; break;
       case 4:
-        str = (char_u *)"[-]"; break;
+        str = "[-]"; break;
       case 5:
-        str = (char_u *)",-"; break;
+        str = ",-"; break;
       case 6:
-        str = (char_u *)"[+-]"; break;
+        str = "[+-]"; break;
       case 7:
-        str = (char_u *)",+-"; break;
+        str = ",+-"; break;
       }
       break;
 
@@ -4199,7 +4195,7 @@ int build_stl_str_hl(win_T *wp, char_u *out, size_t outlen, char_u *fmt, int use
     if (str != NULL && *str) {
       // { Skip the leading `,` or ` ` if the item is a flag
       //  and the proper conditions are met
-      char_u *t = str;
+      char_u *t = (char_u *)str;
       if (itemisflag) {
         if ((t[0] && t[1])
             && ((!prevchar_isitem && *t == ',')
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index ca903fdcf7..7a24ee1b32 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -3292,16 +3292,11 @@ void get_complete_info(list_T *what_list, dict_T *retdict)
           dict_T *di = tv_dict_alloc();
 
           tv_list_append_dict(li, di);
-          tv_dict_add_str(di, S_LEN("word"),
-                          (char *)EMPTY_IF_NULL(match->cp_str));
-          tv_dict_add_str(di, S_LEN("abbr"),
-                          (char *)EMPTY_IF_NULL(match->cp_text[CPT_ABBR]));
-          tv_dict_add_str(di, S_LEN("menu"),
-                          (char *)EMPTY_IF_NULL(match->cp_text[CPT_MENU]));
-          tv_dict_add_str(di, S_LEN("kind"),
-                          (char *)EMPTY_IF_NULL(match->cp_text[CPT_KIND]));
-          tv_dict_add_str(di, S_LEN("info"),
-                          (char *)EMPTY_IF_NULL(match->cp_text[CPT_INFO]));
+          tv_dict_add_str(di, S_LEN("word"), EMPTY_IF_NULL(match->cp_str));
+          tv_dict_add_str(di, S_LEN("abbr"), EMPTY_IF_NULL(match->cp_text[CPT_ABBR]));
+          tv_dict_add_str(di, S_LEN("menu"), EMPTY_IF_NULL(match->cp_text[CPT_MENU]));
+          tv_dict_add_str(di, S_LEN("kind"), EMPTY_IF_NULL(match->cp_text[CPT_KIND]));
+          tv_dict_add_str(di, S_LEN("info"), EMPTY_IF_NULL(match->cp_text[CPT_INFO]));
           if (match->cp_user_data.v_type == VAR_UNKNOWN) {
             tv_dict_add_str(di, S_LEN("user_data"), "");
           } else {
@@ -4635,16 +4630,11 @@ static dict_T *ins_compl_dict_alloc(compl_T *match)
 {
   // { word, abbr, menu, kind, info }
   dict_T *dict = tv_dict_alloc_lock(VAR_FIXED);
-  tv_dict_add_str(dict, S_LEN("word"),
-                  (const char *)EMPTY_IF_NULL(match->cp_str));
-  tv_dict_add_str(dict, S_LEN("abbr"),
-                  (const char *)EMPTY_IF_NULL(match->cp_text[CPT_ABBR]));
-  tv_dict_add_str(dict, S_LEN("menu"),
-                  (const char *)EMPTY_IF_NULL(match->cp_text[CPT_MENU]));
-  tv_dict_add_str(dict, S_LEN("kind"),
-                  (const char *)EMPTY_IF_NULL(match->cp_text[CPT_KIND]));
-  tv_dict_add_str(dict, S_LEN("info"),
-                  (const char *)EMPTY_IF_NULL(match->cp_text[CPT_INFO]));
+  tv_dict_add_str(dict, S_LEN("word"), EMPTY_IF_NULL(match->cp_str));
+  tv_dict_add_str(dict, S_LEN("abbr"), EMPTY_IF_NULL(match->cp_text[CPT_ABBR]));
+  tv_dict_add_str(dict, S_LEN("menu"), EMPTY_IF_NULL(match->cp_text[CPT_MENU]));
+  tv_dict_add_str(dict, S_LEN("kind"), EMPTY_IF_NULL(match->cp_text[CPT_KIND]));
+  tv_dict_add_str(dict, S_LEN("info"), EMPTY_IF_NULL(match->cp_text[CPT_INFO]));
   if (match->cp_user_data.v_type == VAR_UNKNOWN) {
     tv_dict_add_str(dict, S_LEN("user_data"), "");
   } else {
diff --git a/src/nvim/eval/encode.c b/src/nvim/eval/encode.c
index b457353838..d694b8a374 100644
--- a/src/nvim/eval/encode.c
+++ b/src/nvim/eval/encode.c
@@ -29,8 +29,6 @@
 #include "nvim/message.h"
 #include "nvim/vim.h"  // For _()
 
-#define utf_ptr2char(b) utf_ptr2char((char_u *)b)
-#define utf_ptr2len(b) ((size_t)utf_ptr2len((char_u *)b))
 #define utf_char2len(b) ((size_t)utf_char2len(b))
 
 const char *const encode_bool_var_names[] = {
@@ -614,8 +612,8 @@ static inline int convert_to_json_string(garray_T *const gap, const char *const
 #define ENCODE_RAW(ch) \
   (ch >= 0x20 && utf_printable(ch))
     for (size_t i = 0; i < utf_len;) {
-      const int ch = utf_ptr2char(utf_buf + i);
-      const size_t shift = (ch == 0? 1: utf_ptr2len(utf_buf + i));
+      const int ch = utf_ptr2char((char_u *)utf_buf + i);
+      const size_t shift = (ch == 0 ? 1 : ((size_t)utf_ptr2len((char_u *)utf_buf + i)));
       assert(shift > 0);
       i += shift;
       switch (ch) {
@@ -654,11 +652,11 @@ static inline int convert_to_json_string(garray_T *const gap, const char *const
     ga_append(gap, '"');
     ga_grow(gap, (int)str_len);
     for (size_t i = 0; i < utf_len;) {
-      const int ch = utf_ptr2char(utf_buf + i);
+      const int ch = utf_ptr2char((char_u *)utf_buf + i);
       const size_t shift = (ch == 0? 1: utf_char2len(ch));
       assert(shift > 0);
       // Is false on invalid unicode, but this should already be handled.
-      assert(ch == 0 || shift == utf_ptr2len(utf_buf + i));
+      assert(ch == 0 || shift == ((size_t)utf_ptr2len((char_u *)utf_buf + i)));
       switch (ch) {
       case BS:
       case TAB:
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index 1d9ebdb596..7549ec7ac8 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -3544,7 +3544,7 @@ static void f_getcwd(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   }
 
   if (from) {
-    xstrlcpy((char *)cwd, (char *)from, MAXPATHL);
+    STRLCPY(cwd, from, MAXPATHL);
   }
 
   rettv->vval.v_string = vim_strsave(cwd);
@@ -4867,7 +4867,7 @@ static void f_histnr(typval_T *argvars, typval_T *rettv, FunPtr fptr)
  */
 static void f_hlID(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
-  rettv->vval.v_number = syn_name2id((const char_u *)tv_get_string(&argvars[0]));
+  rettv->vval.v_number = syn_name2id(tv_get_string(&argvars[0]));
 }
 
 /*
@@ -4875,7 +4875,7 @@ static void f_hlID(typval_T *argvars, typval_T *rettv, FunPtr fptr)
  */
 static void f_hlexists(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {
-  rettv->vval.v_number = highlight_exists((const char_u *)tv_get_string(&argvars[0]));
+  rettv->vval.v_number = highlight_exists(tv_get_string(&argvars[0]));
 }
 
 /*
diff --git a/src/nvim/eval/userfunc.c b/src/nvim/eval/userfunc.c
index 6fe75e5e1f..80a22f6f9d 100644
--- a/src/nvim/eval/userfunc.c
+++ b/src/nvim/eval/userfunc.c
@@ -1818,7 +1818,7 @@ char_u *trans_function_name(char_u **pp, bool skip, int flags, funcdict_T *fdp,
   if (name != NULL) {
     name = vim_strsave(name);
     *pp = (char_u *)end;
-    if (strncmp((char *)name, "<SNR>", 5) == 0) {
+    if (STRNCMP(name, "<SNR>", 5) == 0) {
       // Change "<SNR>" to the byte sequence.
       name[0] = K_SPECIAL;
       name[1] = KS_EXTRA;
diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index 145fe33284..66e30bdf2b 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -1440,7 +1440,7 @@ static void do_filter(linenr_T line1, linenr_T line2, exarg_T *eap, char_u *cmd,
                      _("%" PRId64 " lines filtered"), (int64_t)linecount);
         if (msg(msg_buf) && !msg_scroll) {
           // save message to display it after redraw
-          set_keep_msg((char_u *)msg_buf, 0);
+          set_keep_msg(msg_buf, 0);
         }
       } else {
         msgmore((long)linecount);
@@ -3280,7 +3280,7 @@ static bool sub_joining_lines(exarg_T *eap, char_u *pat, char_u *sub, char_u *cm
   // TODO(vim): find a generic solution to make line-joining operations more
   // efficient, avoid allocating a string that grows in size.
   if (pat != NULL
-      && strcmp((const char *)pat, "\\n") == 0
+      && STRCMP(pat, "\\n") == 0
       && *sub == NUL
       && (*cmd == NUL || (cmd[1] == NUL
                           && (*cmd == 'g'
@@ -4468,7 +4468,7 @@ bool do_sub_msg(bool count_only)
                      (int64_t)sub_nsubs, (int64_t)sub_nlines);
     if (msg(msg_buf)) {
       // save message to display it after redraw
-      set_keep_msg((char_u *)msg_buf, 0);
+      set_keep_msg(msg_buf, 0);
     }
     return true;
   }
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index 499c6ed4f9..e622a2a68f 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -2647,7 +2647,7 @@ static char_u *find_command(exarg_T *eap, int *full)
       const int c2 = len == 1 ? NUL : eap->cmd[1];
 
       if (command_count != CMD_SIZE) {
-        iemsg((char *)_("E943: Command table needs to be updated, run 'make'"));
+        iemsg(_("E943: Command table needs to be updated, run 'make'"));
         getout(1);
       }
 
@@ -9130,7 +9130,7 @@ char_u *eval_vars(char_u *src, char_u *srcstart, size_t *usedlen, linenr_T *lnum
         // postponed to avoid a delay when <afile> is not used.
         result = (char_u *)FullName_save((char *)autocmd_fname, false);
         // Copy into `autocmd_fname`, don't reassign it. #8165
-        xstrlcpy((char *)autocmd_fname, (char *)result, MAXPATHL);
+        STRLCPY(autocmd_fname, result, MAXPATHL);
         xfree(result);
       }
       result = autocmd_fname;
diff --git a/src/nvim/ex_eval.c b/src/nvim/ex_eval.c
index cfc8eb7316..348a26d723 100644
--- a/src/nvim/ex_eval.c
+++ b/src/nvim/ex_eval.c
@@ -566,7 +566,7 @@ static void discard_exception(except_T *excp, bool was_finished)
     } else {
       verbose_leave();
     }
-    xstrlcpy((char *)IObuff, (const char *)saved_IObuff, IOSIZE);
+    STRLCPY(IObuff, saved_IObuff, IOSIZE);
     xfree(saved_IObuff);
   }
   if (excp->type != ET_INTERRUPT) {
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 9ccbdbaf58..0716b5445d 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -2697,7 +2697,7 @@ static void color_expr_cmdline(const CmdlineInfo *const colored_ccline,
         .attr = 0,
       }));
     }
-    const int id = syn_name2id((const char_u *)chunk.group);
+    const int id = syn_name2id(chunk.group);
     const int attr = (id == 0 ? 0 : syn_id2attr(id));
     kv_push(ret_ccline_colors->colors, ((CmdlineColorChunk) {
       .start = (int)chunk.start.col,
@@ -2899,7 +2899,7 @@ static bool color_cmdline(CmdlineInfo *colored_ccline)
     if (group == NULL) {
       goto color_cmdline_error;
     }
-    const int id = syn_name2id((char_u *)group);
+    const int id = syn_name2id(group);
     const int attr = (id == 0 ? 0 : syn_id2attr(id));
     kv_push(ccline_colors->colors, ((CmdlineColorChunk) {
       .start = (int)start,
@@ -4989,13 +4989,13 @@ static int ExpandFromContext(expand_T *xp, char_u *pat, int *num_file, char_u **
 
   // When expanding a function name starting with s:, match the <SNR>nr_
   // prefix.
-  char_u *tofree = NULL;
+  char *tofree = NULL;
   if (xp->xp_context == EXPAND_USER_FUNC && STRNCMP(pat, "^s:", 3) == 0) {
     const size_t len = STRLEN(pat) + 20;
 
     tofree = xmalloc(len);
-    snprintf((char *)tofree, len, "^<SNR>\\d\\+_%s", pat + 3);
-    pat = tofree;
+    snprintf(tofree, len, "^<SNR>\\d\\+_%s", pat + 3);
+    pat = (char_u *)tofree;
   }
 
   if (xp->xp_context == EXPAND_LUA) {
diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index cf4037308b..321d884d9c 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -125,7 +125,7 @@ void filemess(buf_T *buf, char_u *name, char_u *s, int attr)
   }
   add_quoted_fname((char *)IObuff, IOSIZE - 100, buf, (const char *)name);
   // Avoid an over-long translation to cause trouble.
-  xstrlcat((char *)IObuff, (const char *)s, IOSIZE);
+  STRLCAT(IObuff, s, IOSIZE);
   // For the first message may have to start a new line.
   // For further ones overwrite the previous one, reset msg_scroll before
   // calling filemess().
@@ -1857,7 +1857,7 @@ failed:
         // - When restart_edit is set (otherwise there will be a delay before
         //   redrawing).
         // - When the screen was scrolled but there is no wait-return prompt.
-        set_keep_msg(p, 0);
+        set_keep_msg((char *)p, 0);
       }
       msg_scrolled_ign = false;
     }
@@ -3536,7 +3536,7 @@ restore_backup:
       }
     }
 
-    set_keep_msg((char_u *)msg_trunc_attr((char *)IObuff, FALSE, 0), 0);
+    set_keep_msg(msg_trunc_attr((char *)IObuff, false, 0), 0);
   }
 
   /* When written everything correctly: reset 'modified'.  Unless not
diff --git a/src/nvim/hardcopy.c b/src/nvim/hardcopy.c
index 296c5cbdbf..ab3f63c93e 100644
--- a/src/nvim/hardcopy.c
+++ b/src/nvim/hardcopy.c
@@ -461,10 +461,10 @@ static void prt_line_number(prt_settings_T *const psettings, const int page_line
 
   // Leave two spaces between the number and the text; depends on
   // PRINT_NUMBER_WIDTH.
-  char_u tbuf[20];
-  snprintf((char *)tbuf, sizeof(tbuf), "%6ld", (long)lnum);
+  char tbuf[20];
+  snprintf(tbuf, sizeof(tbuf), "%6ld", (long)lnum);
   for (int i = 0; i < 6; i++) {
-    (void)mch_print_text_out(&tbuf[i], 1);
+    (void)mch_print_text_out((char_u *)(&tbuf[i]), 1);
   }
 
   if (psettings->do_syntax) {
@@ -669,7 +669,7 @@ void ex_hardcopy(exarg_T *eap)
 
   // Syntax highlighting of line numbers.
   if (prt_use_number() && settings.do_syntax) {
-    int id = syn_name2id((char_u *)"LineNr");
+    int id = syn_name2id("LineNr");
     if (id > 0) {
       id = syn_get_final_id(id);
     }
@@ -1310,7 +1310,7 @@ static int prt_collate;
 /*
  * Buffers used when generating PostScript output
  */
-static char_u prt_line_buffer[257];
+static char prt_line_buffer[257];
 static garray_T prt_ps_buffer = GA_EMPTY_INIT_VALUE;
 
 static int prt_do_conv;
@@ -1334,9 +1334,9 @@ static void prt_write_file_raw_len(char_u *buffer, size_t bytes)
   }
 }
 
-static void prt_write_file(char_u *buffer)
+static void prt_write_file(char *buffer)
 {
-  prt_write_file_len(buffer, STRLEN(buffer));
+  prt_write_file_len((char_u *)buffer, STRLEN(buffer));
 }
 
 static void prt_write_file_len(char_u *buffer, size_t bytes)
@@ -1349,7 +1349,7 @@ static void prt_write_file_len(char_u *buffer, size_t bytes)
  */
 static void prt_write_string(char *s)
 {
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer), "%s", s);
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer), "%s", s);
   prt_write_file(prt_line_buffer);
 }
 
@@ -1358,7 +1358,7 @@ static void prt_write_string(char *s)
  */
 static void prt_write_int(int i)
 {
-  sprintf((char *)prt_line_buffer, "%d ", i);
+  snprintf(prt_line_buffer, sizeof(prt_line_buffer), "%d ", i);
   prt_write_file(prt_line_buffer);
 }
 
@@ -1367,7 +1367,7 @@ static void prt_write_int(int i)
  */
 static void prt_write_boolean(int b)
 {
-  sprintf((char *)prt_line_buffer, "%s ", (b ? "T" : "F"));
+  snprintf(prt_line_buffer, sizeof(prt_line_buffer), "%s ", (b ? "T" : "F"));
   prt_write_file(prt_line_buffer);
 }
 
@@ -1376,14 +1376,14 @@ static void prt_write_boolean(int b)
  */
 static void prt_def_font(char *new_name, char *encoding, int height, char *font)
 {
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                "/_%s /VIM-%s /%s ref\n", new_name, encoding, font);
   prt_write_file(prt_line_buffer);
   if (prt_out_mbyte) {
-    sprintf((char *)prt_line_buffer, "/%s %d %f /_%s sffs\n",
-            new_name, height, 500./prt_ps_courier_font.wx, new_name);
+    snprintf(prt_line_buffer, sizeof(prt_line_buffer), "/%s %d %f /_%s sffs\n",
+             new_name, height, 500./prt_ps_courier_font.wx, new_name);
   } else {
-    vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+    vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                  "/%s %d /_%s ffs\n", new_name, height, new_name);
   }
   prt_write_file(prt_line_buffer);
@@ -1394,10 +1394,10 @@ static void prt_def_font(char *new_name, char *encoding, int height, char *font)
  */
 static void prt_def_cidfont(char *new_name, int height, char *cidfont)
 {
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                "/_%s /%s[/%s] vim_composefont\n", new_name, prt_cmap, cidfont);
   prt_write_file(prt_line_buffer);
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                "/%s %d /_%s ffs\n", new_name, height, new_name);
   prt_write_file(prt_line_buffer);
 }
@@ -1407,7 +1407,7 @@ static void prt_def_cidfont(char *new_name, int height, char *cidfont)
  */
 static void prt_dup_cidfont(char *original_name, char *new_name)
 {
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                "/%s %s d\n", new_name, original_name);
   prt_write_file(prt_line_buffer);
 }
@@ -1444,7 +1444,7 @@ static void prt_write_real(double val, int prec)
 
   prt_real_bits(val, prec, &integer, &fraction);
   // Emit integer part
-  snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer), "%d", integer);
+  snprintf(prt_line_buffer, sizeof(prt_line_buffer), "%d", integer);
   prt_write_file(prt_line_buffer);
   // Only emit fraction if necessary
   if (fraction != 0) {
@@ -1454,11 +1454,11 @@ static void prt_write_real(double val, int prec)
       fraction /= 10;
     }
     // Emit fraction left padded with zeros
-    snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer), ".%0*d",
+    snprintf(prt_line_buffer, sizeof(prt_line_buffer), ".%0*d",
              prec, fraction);
     prt_write_file(prt_line_buffer);
   }
-  sprintf((char *)prt_line_buffer, " ");
+  snprintf(prt_line_buffer, sizeof(prt_line_buffer), " ");
   prt_write_file(prt_line_buffer);
 }
 
@@ -1467,11 +1467,11 @@ static void prt_write_real(double val, int prec)
  */
 static void prt_def_var(char *name, double value, int prec)
 {
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                "/%s ", name);
   prt_write_file(prt_line_buffer);
   prt_write_real(value, prec);
-  sprintf((char *)prt_line_buffer, "d\n");
+  snprintf(prt_line_buffer, sizeof(prt_line_buffer), "d\n");
   prt_write_file(prt_line_buffer);
 }
 
@@ -1569,8 +1569,8 @@ static int prt_find_resource(char *name, struct prt_ps_resource_S *resource)
   // Look for named resource file in runtimepath
   STRCPY(buffer, "print");
   add_pathsep((char *)buffer);
-  xstrlcat((char *)buffer, name, MAXPATHL);
-  xstrlcat((char *)buffer, ".ps", MAXPATHL);
+  STRLCAT(buffer, name, MAXPATHL);
+  STRLCAT(buffer, ".ps", MAXPATHL);
   resource->filename[0] = NUL;
   retval = (do_in_runtimepath(buffer, 0, prt_resource_name, resource->filename)
             && resource->filename[0] != NUL);
@@ -1833,14 +1833,14 @@ static void prt_dsc_start(void)
 
 static void prt_dsc_noarg(char *comment)
 {
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                "%%%%%s\n", comment);
   prt_write_file(prt_line_buffer);
 }
 
 static void prt_dsc_textline(char *comment, char *text)
 {
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                "%%%%%s: %s\n", comment, text);
   prt_write_file(prt_line_buffer);
 }
@@ -1848,7 +1848,7 @@ static void prt_dsc_textline(char *comment, char *text)
 static void prt_dsc_text(char *comment, char *text)
 {
   // TODO(vim): - should scan 'text' for any chars needing escaping!
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                "%%%%%s: (%s)\n", comment, text);
   prt_write_file(prt_line_buffer);
 }
@@ -1859,12 +1859,12 @@ static void prt_dsc_ints(char *comment, int count, int *ints)
 {
   int i;
 
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                "%%%%%s:", comment);
   prt_write_file(prt_line_buffer);
 
   for (i = 0; i < count; i++) {
-    sprintf((char *)prt_line_buffer, " %d", ints[i]);
+    snprintf(prt_line_buffer, sizeof(prt_line_buffer), " %d", ints[i]);
     prt_write_file(prt_line_buffer);
   }
 
@@ -1876,15 +1876,15 @@ static void prt_dsc_resources(const char *comment, const char *type, const char
   FUNC_ATTR_NONNULL_ARG(2, 3)
 {
   if (comment != NULL) {
-    vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+    vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                  "%%%%%s: %s", comment, type);
   } else {
-    vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+    vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                  "%%%%+ %s", type);
   }
   prt_write_file(prt_line_buffer);
 
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                " %s\n", string);
   prt_write_file(prt_line_buffer);
 }
@@ -1910,7 +1910,7 @@ static void prt_dsc_requirements(int duplex, int tumble, int collate, int color,
     return;
   }
 
-  sprintf((char *)prt_line_buffer, "%%%%Requirements:");
+  snprintf(prt_line_buffer, sizeof(prt_line_buffer), "%%%%Requirements:");
   prt_write_file(prt_line_buffer);
 
   if (duplex) {
@@ -1928,7 +1928,7 @@ static void prt_dsc_requirements(int duplex, int tumble, int collate, int color,
   if (num_copies > 1) {
     prt_write_string(" numcopies(");
     // Note: no space wanted so don't use prt_write_int()
-    snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer), "%d",
+    snprintf(prt_line_buffer, sizeof(prt_line_buffer), "%d",
              num_copies);
     prt_write_file(prt_line_buffer);
     prt_write_string(")");
@@ -1939,7 +1939,7 @@ static void prt_dsc_requirements(int duplex, int tumble, int collate, int color,
 static void prt_dsc_docmedia(char *paper_name, double width, double height, double weight,
                              char *colour, char *type)
 {
-  vim_snprintf((char *)prt_line_buffer, sizeof(prt_line_buffer),
+  vim_snprintf(prt_line_buffer, sizeof(prt_line_buffer),
                "%%%%DocumentMedia: %s ", paper_name);
   prt_write_file(prt_line_buffer);
   prt_write_real(width, 2);
@@ -2492,7 +2492,7 @@ int mch_print_begin(prt_settings_T *psettings)
   struct prt_ps_resource_S res_prolog;
   struct prt_ps_resource_S res_encoding;
   char buffer[256];
-  char_u *p_encoding;
+  char *p_encoding;
   char_u *p;
   struct prt_ps_resource_S res_cidfont;
   struct prt_ps_resource_S res_cmap;
@@ -2595,20 +2595,20 @@ int mch_print_begin(prt_settings_T *psettings)
   // that cannot be found then default to "latin1".
   // Note: VIM specific encoding header is always skipped.
   if (!prt_out_mbyte) {
-    p_encoding = enc_skip(p_penc);
+    p_encoding = (char *)enc_skip(p_penc);
     if (*p_encoding == NUL
-        || !prt_find_resource((char *)p_encoding, &res_encoding)) {
+        || !prt_find_resource(p_encoding, &res_encoding)) {
       // 'printencoding' not set or not supported - find alternate
       int props;
 
-      p_encoding = enc_skip(p_enc);
-      props = enc_canon_props(p_encoding);
+      p_encoding = (char *)enc_skip(p_enc);
+      props = enc_canon_props((char_u *)p_encoding);
       if (!(props & ENC_8BIT)
-          || !prt_find_resource((char *)p_encoding, &res_encoding)) {
+          || !prt_find_resource(p_encoding, &res_encoding)) {
         // 8-bit 'encoding' is not supported
         // Use latin1 as default printing encoding
-        p_encoding = (char_u *)"latin1";
-        if (!prt_find_resource((char *)p_encoding, &res_encoding)) {
+        p_encoding = "latin1";
+        if (!prt_find_resource(p_encoding, &res_encoding)) {
           semsg(_("E456: Can't find PostScript resource file \"%s.ps\""),
                 p_encoding);
           return FALSE;
@@ -2621,9 +2621,9 @@ int mch_print_begin(prt_settings_T *psettings)
     // For the moment there are no checks on encoding resource files to
     // perform
   } else {
-    p_encoding = enc_skip(p_penc);
+    p_encoding = (char *)enc_skip(p_penc);
     if (*p_encoding == NUL) {
-      p_encoding = enc_skip(p_enc);
+      p_encoding = (char *)enc_skip(p_enc);
     }
     if (prt_use_courier) {
       // Include ASCII range encoding vector
@@ -2641,9 +2641,9 @@ int mch_print_begin(prt_settings_T *psettings)
   }
 
   prt_conv.vc_type = CONV_NONE;
-  if (!(enc_canon_props(p_enc) & enc_canon_props(p_encoding) & ENC_8BIT)) {
+  if (!(enc_canon_props(p_enc) & enc_canon_props((char_u *)p_encoding) & ENC_8BIT)) {
     // Set up encoding conversion if required
-    if (convert_setup(&prt_conv, p_enc, p_encoding) == FAIL) {
+    if (convert_setup(&prt_conv, p_enc, (char_u *)p_encoding) == FAIL) {
       semsg(_("E620: Unable to convert to print encoding \"%s\""),
             p_encoding);
       return false;
@@ -2766,23 +2766,23 @@ int mch_print_begin(prt_settings_T *psettings)
     // When using Courier for ASCII range when printing multi-byte, need to
     // pick up ASCII encoding to use with it.
     if (prt_use_courier) {
-      p_encoding = (char_u *)prt_ascii_encoding;
+      p_encoding = prt_ascii_encoding;
     }
     prt_dsc_resources("IncludeResource", "font",
                       prt_ps_courier_font.ps_fontname[PRT_PS_FONT_ROMAN]);
-    prt_def_font("F0", (char *)p_encoding, (int)prt_line_height,
+    prt_def_font("F0", p_encoding, (int)prt_line_height,
                  prt_ps_courier_font.ps_fontname[PRT_PS_FONT_ROMAN]);
     prt_dsc_resources("IncludeResource", "font",
                       prt_ps_courier_font.ps_fontname[PRT_PS_FONT_BOLD]);
-    prt_def_font("F1", (char *)p_encoding, (int)prt_line_height,
+    prt_def_font("F1", p_encoding, (int)prt_line_height,
                  prt_ps_courier_font.ps_fontname[PRT_PS_FONT_BOLD]);
     prt_dsc_resources("IncludeResource", "font",
                       prt_ps_courier_font.ps_fontname[PRT_PS_FONT_OBLIQUE]);
-    prt_def_font("F2", (char *)p_encoding, (int)prt_line_height,
+    prt_def_font("F2", p_encoding, (int)prt_line_height,
                  prt_ps_courier_font.ps_fontname[PRT_PS_FONT_OBLIQUE]);
     prt_dsc_resources("IncludeResource", "font",
                       prt_ps_courier_font.ps_fontname[PRT_PS_FONT_BOLDOBLIQUE]);
-    prt_def_font("F3", (char *)p_encoding, (int)prt_line_height,
+    prt_def_font("F3", p_encoding, (int)prt_line_height,
                  prt_ps_courier_font.ps_fontname[PRT_PS_FONT_BOLDOBLIQUE]);
   }
   if (prt_out_mbyte) {
@@ -2865,7 +2865,7 @@ void mch_print_end(prt_settings_T *psettings)
 
   // Write CTRL-D to close serial communication link if used.
   // NOTHING MUST BE WRITTEN AFTER THIS!
-  prt_write_file((char_u *)"\004");
+  prt_write_file("\004");
 
   if (!prt_file_error && psettings->outfile == NULL
       && !got_int && !psettings->user_abort) {
diff --git a/src/nvim/if_cscope.c b/src/nvim/if_cscope.c
index 5b5f056164..2c44ce380d 100644
--- a/src/nvim/if_cscope.c
+++ b/src/nvim/if_cscope.c
@@ -601,7 +601,7 @@ static int cs_cnt_matches(size_t idx)
     if ((stok = strtok(NULL, (const char *)" ")) == NULL) {
       continue;
     }
-    if (strncmp((const char *)stok, "lines", 5)) {
+    if (strncmp(stok, "lines", 5)) {
       continue;
     }
 
@@ -1214,8 +1214,8 @@ static cscmd_T *cs_lookup_cmd(exarg_T *eap)
   }
 
   len = strlen(stok);
-  for (cmdp = cs_cmds; cmdp->name != NULL; ++cmdp) {
-    if (strncmp((const char *)(stok), cmdp->name, len) == 0) {
+  for (cmdp = cs_cmds; cmdp->name != NULL; cmdp++) {
+    if (strncmp(stok, cmdp->name, len) == 0) {
       return cmdp;
     }
   }
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index b27b1ae7a8..6a8b70a158 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -957,7 +957,7 @@ int nlua_source_using_linegetter(LineGetter fgetline, void *cookie, char *name)
   while ((line = fgetline(0, cookie, 0, false)) != NULL) {
     GA_APPEND(char_u *, &ga, line);
   }
-  char *code = (char *)ga_concat_strings_sep(&ga, "\n");
+  char *code = ga_concat_strings_sep(&ga, "\n");
   size_t len = strlen(code);
   nlua_typval_exec(code, len, name, NULL, 0, false, NULL);
 
diff --git a/src/nvim/macros.h b/src/nvim/macros.h
index faef0f69b2..c2b2c89abf 100644
--- a/src/nvim/macros.h
+++ b/src/nvim/macros.h
@@ -54,7 +54,7 @@
 #define ASCII_ISALNUM(c) (ASCII_ISALPHA(c) || ascii_isdigit(c))
 
 // Returns empty string if it is NULL.
-#define EMPTY_IF_NULL(x) ((x) ? (x) : (char_u *)"")
+#define EMPTY_IF_NULL(x) (char *)((x) ? (x) : (char_u *)"")
 
 // Adjust chars in a language according to 'langmap' option.
 // NOTE that there is no noticeable overhead if 'langmap' is not set.
diff --git a/src/nvim/memline.c b/src/nvim/memline.c
index 456b1013c1..edab367f02 100644
--- a/src/nvim/memline.c
+++ b/src/nvim/memline.c
@@ -2564,7 +2564,7 @@ static int ml_delete_int(buf_T *buf, linenr_T lnum, bool message)
    */
   if (buf->b_ml.ml_line_count == 1) {       // file becomes empty
     if (message) {
-      set_keep_msg((char_u *)_(no_lines_msg), 0);
+      set_keep_msg(_(no_lines_msg), 0);
     }
 
     i = ml_replace((linenr_T)1, (char_u *)"", true);
diff --git a/src/nvim/message.c b/src/nvim/message.c
index 7b6337bea2..8223e6c188 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -329,7 +329,7 @@ bool msg_attr_keep(const char *s, int attr, bool keep, bool multiline)
 
   if (keep && retval && vim_strsize((char_u *)s) < (int)(Rows - cmdline_row - 1)
       * Columns + sc_col) {
-    set_keep_msg((char_u *)s, 0);
+    set_keep_msg((char *)s, 0);
   }
 
   xfree(buf);
@@ -732,7 +732,7 @@ static bool emsg_multiline(const char *s, bool multiline)
 /// @return true if wait_return not called
 bool emsg(const char *s)
 {
-  return emsg_multiline((const char *)s, false);
+  return emsg_multiline(s, false);
 }
 
 void emsg_invreg(int name)
@@ -1288,11 +1288,11 @@ static void hit_return_msg(void)
 /*
  * Set "keep_msg" to "s".  Free the old value and check for NULL pointer.
  */
-void set_keep_msg(char_u *s, int attr)
+void set_keep_msg(char *s, int attr)
 {
   xfree(keep_msg);
   if (s != NULL && msg_silent == 0) {
-    keep_msg = vim_strsave(s);
+    keep_msg = vim_strsave((char_u *)s);
   } else {
     keep_msg = NULL;
   }
@@ -3342,7 +3342,7 @@ void give_warning(char_u *message, bool hl) FUNC_ATTR_NONNULL_ARG(1)
   }
 
   if (msg_attr((const char *)message, keep_msg_attr) && msg_scrolled == 0) {
-    set_keep_msg(message, keep_msg_attr);
+    set_keep_msg((char *)message, keep_msg_attr);
   }
   msg_didout = false;  // Overwrite this message.
   msg_nowait = true;   // Don't wait for this message.
diff --git a/src/nvim/misc1.c b/src/nvim/misc1.c
index faf0b0f633..5ecd4ca431 100644
--- a/src/nvim/misc1.c
+++ b/src/nvim/misc1.c
@@ -699,7 +699,7 @@ void msgmore(long n)
       xstrlcat(msg_buf, _(" (Interrupted)"), MSG_BUF_LEN);
     }
     if (msg(msg_buf)) {
-      set_keep_msg((char_u *)msg_buf, 0);
+      set_keep_msg(msg_buf, 0);
       keep_msg_more = true;
     }
   }
diff --git a/src/nvim/option.c b/src/nvim/option.c
index b7df856949..5dd7d708f9 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -2419,7 +2419,7 @@ static char *did_set_string_option(int opt_idx, char_u **varp, bool new_value_al
     }
   } else if (varp == &p_hl) {
     // 'highlight'
-    if (strcmp((char *)(*varp), HIGHLIGHT_INIT) != 0) {
+    if (STRCMP(*varp, HIGHLIGHT_INIT) != 0) {
       errmsg = e_unsupportedoption;
     }
   } else if (varp == &p_jop) {  // 'jumpoptions'
diff --git a/src/nvim/os/env.c b/src/nvim/os/env.c
index 727b10f7a7..e9f44d2775 100644
--- a/src/nvim/os/env.c
+++ b/src/nvim/os/env.c
@@ -1048,7 +1048,7 @@ size_t home_replace(const buf_T *const buf, const char_u *src, char_u *const dst
   }
 
   if (buf != NULL && buf->b_help) {
-    const size_t dlen = xstrlcpy((char *)dst, (char *)path_tail(src), dstlen);
+    const size_t dlen = STRLCPY(dst, path_tail(src), dstlen);
     return MIN(dlen, dstlen - 1);
   }
 
diff --git a/src/nvim/path.c b/src/nvim/path.c
index 1085f7a10c..c28d848683 100644
--- a/src/nvim/path.c
+++ b/src/nvim/path.c
@@ -65,7 +65,7 @@ FileComparison path_full_compare(char_u *const s1, char_u *const s2, const bool
   if (expandenv) {
     expand_env(s1, exp1, MAXPATHL);
   } else {
-    xstrlcpy((char *)exp1, (const char *)s1, MAXPATHL);
+    STRLCPY(exp1, s1, MAXPATHL);
   }
   bool id_ok_1 = os_fileid((char *)exp1, &file_id_1);
   bool id_ok_2 = os_fileid((char *)s2, &file_id_2);
@@ -2395,9 +2395,9 @@ void path_guess_exepath(const char *argv0, char *buf, size_t bufsize)
       if (dir_len + 1 > sizeof(NameBuff)) {
         continue;
       }
-      xstrlcpy((char *)NameBuff, dir, dir_len + 1);
-      xstrlcat((char *)NameBuff, PATHSEPSTR, sizeof(NameBuff));
-      xstrlcat((char *)NameBuff, argv0, sizeof(NameBuff));
+      STRLCPY(NameBuff, dir, dir_len + 1);
+      STRLCAT(NameBuff, PATHSEPSTR, sizeof(NameBuff));
+      STRLCAT(NameBuff, argv0, sizeof(NameBuff));
       if (os_can_exe((char *)NameBuff, NULL, false)) {
         xstrlcpy(buf, (char *)NameBuff, bufsize);
         return;
diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index 950d187ad5..bf9052de6f 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -1183,7 +1183,7 @@ static void qf_store_title(qf_list_T *qfl, const char_u *title)
     char_u *p = xmallocz(len);
 
     qfl->qf_title = p;
-    xstrlcpy((char *)p, (const char *)title, len + 1);
+    STRLCPY(p, title, len + 1);
   }
 }
 
@@ -1402,7 +1402,7 @@ static int qf_parse_fmt_s(regmatch_T *rmp, int midx, qffields_T *fields)
     len = CMDBUFFSIZE - 5;
   }
   STRCPY(fields->pattern, "^\\V");
-  xstrlcat((char *)fields->pattern, (char *)rmp->startp[midx], len + 4);
+  STRLCAT(fields->pattern, rmp->startp[midx], len + 4);
   fields->pattern[len + 3] = '\\';
   fields->pattern[len + 4] = '$';
   fields->pattern[len + 5] = NUL;
@@ -1424,7 +1424,7 @@ static int qf_parse_fmt_o(regmatch_T *rmp, int midx, qffields_T *fields)
   if (dsize > CMDBUFFSIZE) {
     dsize = CMDBUFFSIZE;
   }
-  xstrlcat((char *)fields->module, (char *)rmp->startp[midx], dsize);
+  STRLCAT(fields->module, rmp->startp[midx], dsize);
   return QF_OK;
 }
 
@@ -3231,7 +3231,7 @@ static void qf_msg(qf_info_T *qi, int which, char *lead)
       memset(buf + len, ' ', 34 - len);
       buf[34] = NUL;
     }
-    xstrlcat((char *)buf, title, IOSIZE);
+    STRLCAT(buf, title, IOSIZE);
   }
   trunc_string(buf, buf, Columns - 1, IOSIZE);
   msg((char *)buf);
diff --git a/src/nvim/runtime.c b/src/nvim/runtime.c
index 674d807e96..14f49d05d5 100644
--- a/src/nvim/runtime.c
+++ b/src/nvim/runtime.c
@@ -872,7 +872,7 @@ static void add_pack_start_dir(char_u *fname, void *cookie)
       continue;
     }
     STRLCPY(buf, fname, MAXPATHL);
-    xstrlcat((char *)buf, start_pat[i], sizeof buf);
+    STRLCAT(buf, start_pat[i], sizeof buf);
     if (pack_has_entries(buf)) {
       add_pack_dir_to_rtp(buf, true);
     }
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index 63e904079e..cc3fab3503 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -3117,7 +3117,7 @@ static int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool noc
               // the match.
               if (cur != NULL
                   && shl != &search_hl
-                  && syn_name2id((char_u *)"Conceal") == cur->hlg_id) {
+                  && syn_name2id("Conceal") == cur->hlg_id) {
                 has_match_conc = v == (long)shl->startcol ? 2 : 1;
                 match_conc = cur->conceal_char;
               } else {
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index 504d1cd16e..8347f1bff1 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -4271,7 +4271,7 @@ static char_u *get_syn_options(char_u *arg, syn_opt_arg_T *opt, int *conceal_cha
         if (STRCMP(gname, "NONE") == 0) {
           *opt->sync_idx = NONE_IDX;
         } else {
-          syn_id = syn_name2id(gname);
+          syn_id = syn_name2id((char *)gname);
           int i;
           for (i = curwin->w_s->b_syn_patterns.ga_len; --i >= 0; ) {
             if (SYN_ITEMS(curwin->w_s)[i].sp_syn.id == syn_id
@@ -5264,7 +5264,7 @@ static void syn_cmd_sync(exarg_T *eap, int syncing)
         }
         next_arg = skipwhite(arg_end);
       } else if (!eap->skip) {
-        curwin->w_s->b_syn_sync_id = syn_name2id((char_u *)"Comment");
+        curwin->w_s->b_syn_sync_id = syn_name2id("Comment");
       }
     } else if (STRNCMP(key, "LINES", 5) == 0
                || STRNCMP(key, "MINLINES", 8) == 0
@@ -7403,9 +7403,9 @@ static bool highlight_list_arg(const int id, bool didh, const int type, int iarg
       for (int i = 0; hl_attr_table[i] != 0; i++) {
         if (iarg & hl_attr_table[i]) {
           if (buf[0] != NUL) {
-            xstrlcat((char *)buf, ",", 100);
+            xstrlcat(buf, ",", 100);
           }
-          xstrlcat((char *)buf, hl_name_table[i], 100);
+          xstrlcat(buf, hl_name_table[i], 100);
           iarg &= ~hl_attr_table[i];                // don't want "inverse"
         }
       }
@@ -7605,10 +7605,10 @@ static void set_hl_attr(int idx)
   }
 }
 
-int syn_name2id(const char_u *name)
+int syn_name2id(const char *name)
   FUNC_ATTR_NONNULL_ALL
 {
-  return syn_name2id_len(name, STRLEN(name));
+  return syn_name2id_len((char_u *)name, STRLEN(name));
 }
 
 /// Lookup a highlight group name and return its ID.
@@ -7641,7 +7641,7 @@ int syn_name2id_len(const char_u *name, size_t len)
 int syn_name2attr(const char_u *name)
   FUNC_ATTR_NONNULL_ALL
 {
-  int id = syn_name2id(name);
+  int id = syn_name2id((char *)name);
 
   if (id != 0) {
     return syn_id2attr(id);
@@ -7652,7 +7652,7 @@ int syn_name2attr(const char_u *name)
 /*
  * Return TRUE if highlight group "name" exists.
  */
-int highlight_exists(const char_u *name)
+int highlight_exists(const char *name)
 {
   return syn_name2id(name) > 0;
 }
@@ -7870,7 +7870,7 @@ static void combine_stl_hlt(int id, int id_S, int id_alt, int hlcnt, int i, int
 void highlight_changed(void)
 {
   int id;
-  char_u userhl[30];  // use 30 to avoid compiler warning
+  char userhl[30];  // use 30 to avoid compiler warning
   int id_S = -1;
   int id_SNC = 0;
   int hlcnt;
@@ -7919,7 +7919,7 @@ void highlight_changed(void)
     id_S = hlcnt + 10;
   }
   for (int i = 0; i < 9; i++) {
-    sprintf((char *)userhl, "User%d", i + 1);
+    snprintf(userhl, sizeof(userhl), "User%d", i + 1);
     id = syn_name2id(userhl);
     if (id == 0) {
       highlight_user[i] = 0;
diff --git a/src/nvim/terminal.c b/src/nvim/terminal.c
index 9002ac4967..35c68fa1f6 100644
--- a/src/nvim/terminal.c
+++ b/src/nvim/terminal.c
@@ -393,7 +393,7 @@ void terminal_enter(void)
   long save_w_p_so = curwin->w_p_so;
   long save_w_p_siso = curwin->w_p_siso;
   if (curwin->w_p_cul && curwin->w_p_culopt_flags & CULOPT_NBR) {
-    if (strcmp((char *)curwin->w_p_culopt, "number")) {
+    if (STRCMP(curwin->w_p_culopt, "number")) {
       save_w_p_culopt = curwin->w_p_culopt;
       curwin->w_p_culopt = (char_u *)xstrdup("number");
     }
diff --git a/src/nvim/window.c b/src/nvim/window.c
index ff5b39eb84..59079584ca 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -569,7 +569,7 @@ wingotofile:
 
 static void cmd_with_count(char *cmd, char_u *bufp, size_t bufsize, int64_t Prenum)
 {
-  size_t len = xstrlcpy((char *)bufp, cmd, bufsize);
+  size_t len = STRLCPY(bufp, cmd, bufsize);
 
   if (Prenum > 0 && len < bufsize) {
     vim_snprintf((char *)bufp + len, bufsize - len, "%" PRId64, Prenum);