23 files changed, 308 insertions, 263 deletions
diff --git a/src/nvim/README.md b/src/nvim/README.md
index e4939d94fd..f16c6de12f 100644
--- a/src/nvim/README.md
+++ b/src/nvim/README.md
@@ -11,7 +11,7 @@ that are constantly changing. As the code becomes more organized and stable,
 this document will be updated to reflect the changes.
 
 If you are looking for module-specific details, it is best to read the source
-code. Some files are extensively commented at the top(eg: terminal.c,
+code. Some files are extensively commented at the top (e.g. terminal.c,
 screen.c).
 
 ### Top-level program loops
@@ -43,13 +43,13 @@ a typical editing session:
 
 Note that we have split user actions into sequences of inputs that change the
 state of the editor. While there's no documentation about a "g command
-mode"(step 16), internally it is implemented similarly to "operator-pending
+mode" (step 16), internally it is implemented similarly to "operator-pending
 mode".
 
 From this we can see that Vim has the behavior of a input-driven state
-machine(more specifically, a pushdown automaton since it requires a stack for
+machine (more specifically, a pushdown automaton since it requires a stack for
 transitioning back from states). Assuming each state has a callback responsible
-for handling keys, this pseudocode(a python-like language) shows a good
+for handling keys, this pseudocode (a python-like language) shows a good
 representation of the main program loop:
 
 ```py
@@ -129,20 +129,20 @@ def insert_state(data, key):
 While the actual code is much more complicated, the above gives an idea of how
 Neovim is organized internally. Some states like the `g_command_state` or
 `get_operator_count_state` do not have a dedicated `state_enter` callback, but
-are implicitly embedded into other states(this will change later as we continue
+are implicitly embedded into other states (this will change later as we continue
 the refactoring effort). To start reading the actual code, here's the
 recommended order:
 
-1. `state_enter()` function(state.c). This is the actual program loop,
+1. `state_enter()` function (state.c). This is the actual program loop,
    note that a `VimState` structure is used, which contains function pointers
    for the callback and state data.
-2. `main()` function(main.c). After all startup, `normal_enter` is called
+2. `main()` function (main.c). After all startup, `normal_enter` is called
    at the end of function to enter normal mode.
-3. `normal_enter()` function(normal.c) is a small wrapper for setting
+3. `normal_enter()` function (normal.c) is a small wrapper for setting
    up the NormalState structure and calling `state_enter`.
-4. `normal_check()` function(normal.c) is called before each iteration of
+4. `normal_check()` function (normal.c) is called before each iteration of
    normal mode.
-5. `normal_execute()` function(normal.c) is called when a key is read in normal
+5. `normal_execute()` function (normal.c) is called when a key is read in normal
    mode.
 
 The basic structure described for normal mode in 3, 4 and 5 is used for other
@@ -159,7 +159,7 @@ asynchronous events, which can include:
 
 - msgpack-rpc requests
 - job control callbacks
-- timers(not implemented yet but the support code is already there)
+- timers (not implemented yet but the support code is already there)
 
 Neovim implements this functionality by entering another event loop while
 waiting for characters, so instead of:
@@ -180,11 +180,11 @@ def state_enter(state_callback, data):
   while state_callback(data, event) # invoke the callback for the current state
 ```
 
-where `event` is something the operating system delivers to us, including(but
+where `event` is something the operating system delivers to us, including (but
 not limited to) user input. The `read_next_event()` part is internally
 implemented by libuv, the platform layer used by Neovim.
 
 Since Neovim inherited its code from Vim, the states are not prepared to receive
-"arbitrary events", so we use a special key to represent those(When a state
+"arbitrary events", so we use a special key to represent those (When a state
 receives an "arbitrary event", it normally doesn't do anything other update the
 screen).
diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index 2776e45f5d..e06ffd0bbc 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -1057,27 +1057,28 @@ void diff_win_options(win_T *wp, int addbuf)
   newFoldLevel();
   curwin = old_curwin;
 
-  wp->w_p_diff = TRUE;
-
   // Use 'scrollbind' and 'cursorbind' when available
-  if (!wp->w_p_diff_saved) {
+  if (!wp->w_p_diff) {
     wp->w_p_scb_save = wp->w_p_scb;
   }
   wp->w_p_scb = TRUE;
 
-  if (!wp->w_p_diff_saved) {
+  if (!wp->w_p_diff) {
     wp->w_p_crb_save = wp->w_p_crb;
   }
   wp->w_p_crb = TRUE;
 
-  if (!wp->w_p_diff_saved) {
+  if (!wp->w_p_diff) {
     wp->w_p_wrap_save = wp->w_p_wrap;
   }
   wp->w_p_wrap = FALSE;
   curwin = wp;
   curbuf = curwin->w_buffer;
 
-  if (!wp->w_p_diff_saved) {
+  if (!wp->w_p_diff) {
+    if (wp->w_p_diff_saved) {
+      free_string_option(wp->w_p_fdm_save);
+    }
     wp->w_p_fdm_save = vim_strsave(wp->w_p_fdm);
   }
   set_string_option_direct((char_u *)"fdm", -1, (char_u *)"diff",
@@ -1085,7 +1086,7 @@ void diff_win_options(win_T *wp, int addbuf)
   curwin = old_curwin;
   curbuf = curwin->w_buffer;
 
-  if (!wp->w_p_diff_saved) {
+  if (!wp->w_p_diff) {
     wp->w_p_fdc_save = wp->w_p_fdc;
     wp->w_p_fen_save = wp->w_p_fen;
     wp->w_p_fdl_save = wp->w_p_fdl;
@@ -1104,6 +1105,8 @@ void diff_win_options(win_T *wp, int addbuf)
   // Saved the current values, to be restored in ex_diffoff().
   wp->w_p_diff_saved = TRUE;
 
+  wp->w_p_diff = true;
+
   if (addbuf) {
     diff_buf_add(wp->w_buffer);
   }
@@ -1116,68 +1119,50 @@ void diff_win_options(win_T *wp, int addbuf)
 /// @param eap
 void ex_diffoff(exarg_T *eap)
 {
-  win_T *old_curwin = curwin;
-  int diffwin = FALSE;
+  int diffwin = false;
 
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
     if (eap->forceit ? wp->w_p_diff : (wp == curwin)) {
-      // Set 'diff', 'scrollbind' off and 'wrap' on. If option values
-      // were saved in diff_win_options() restore them.
-      wp->w_p_diff = FALSE;
-
-      if (wp->w_p_scb) {
-        wp->w_p_scb = wp->w_p_diff_saved ? wp->w_p_scb_save : FALSE;
-      }
-
-      if (wp->w_p_crb) {
-        wp->w_p_crb = wp->w_p_diff_saved ? wp->w_p_crb_save : FALSE;
-      }
-
-      if (!wp->w_p_wrap) {
-        wp->w_p_wrap = wp->w_p_diff_saved ? wp->w_p_wrap_save : TRUE;
-      }
-      curwin = wp;
-      curbuf = curwin->w_buffer;
+      // Set 'diff' off. If option values were saved in
+      // diff_win_options(), restore the ones whose settings seem to have
+      // been left over from diff mode.
+      wp->w_p_diff = false;
 
       if (wp->w_p_diff_saved) {
-        free_string_option(wp->w_p_fdm);
-        wp->w_p_fdm = wp->w_p_fdm_save;
-        wp->w_p_fdm_save = empty_option;
-      } else {
-        set_string_option_direct((char_u *)"fdm", -1,
-                                 (char_u *)"manual", OPT_LOCAL | OPT_FREE, 0);
-      }
-      curwin = old_curwin;
-      curbuf = curwin->w_buffer;
+        if (wp->w_p_scb) {
+          wp->w_p_scb = wp->w_p_scb_save;
+        }
 
-      if (wp->w_p_fdc == diff_foldcolumn) {
-        wp->w_p_fdc = wp->w_p_diff_saved ? wp->w_p_fdc_save : 0;
-      }
+        if (wp->w_p_crb) {
+          wp->w_p_crb = wp->w_p_crb_save;
+        }
 
-      if ((wp->w_p_fdl == 0)
-          && wp->w_p_diff_saved) {
-        wp->w_p_fdl = wp->w_p_fdl_save;
-      }
+        if (!wp->w_p_wrap) {
+          wp->w_p_wrap = wp->w_p_wrap_save;
+        }
 
-      if (wp->w_p_fen) {
+        free_string_option(wp->w_p_fdm);
+        wp->w_p_fdm = vim_strsave(wp->w_p_fdm_save);
+        if (wp->w_p_fdc == diff_foldcolumn) {
+          wp->w_p_fdc = wp->w_p_fdc_save;
+        }
+        if (wp->w_p_fdl == 0) {
+          wp->w_p_fdl = wp->w_p_fdl_save;
+        }
         // Only restore 'foldenable' when 'foldmethod' is not
         // "manual", otherwise we continue to show the diff folds.
-        if (foldmethodIsManual(wp) || !wp->w_p_diff_saved) {
-          wp->w_p_fen = FALSE;
-        } else {
-          wp->w_p_fen = wp->w_p_fen_save;
+        if (wp->w_p_fen) {
+          wp->w_p_fen = foldmethodIsManual(wp) ? false : wp->w_p_fen_save;
         }
-      }
 
-      foldUpdateAll(wp);
+        foldUpdateAll(wp);
 
-      // make sure topline is not halfway through a fold
-      changed_window_setting_win(wp);
+        // make sure topline is not halfway through a fold
+        changed_window_setting_win(wp);
+      }
 
       // Note: 'sbo' is not restored, it's a global option.
       diff_buf_adjust(wp);
-
-      wp->w_p_diff_saved = FALSE;
     }
     diffwin |= wp->w_p_diff;
   }
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index dbbcf4f1b9..213df4f65a 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -2548,8 +2548,12 @@ void ins_compl_show_pum(void)
       }
   }
 
-  /* Compute the screen column of the start of the completed text.
-   * Use the cursor to get all wrapping and other settings right. */
+  // In Replace mode when a $ is displayed at the end of the line only
+  // part of the screen would be updated.  We do need to redraw here.
+  dollar_vcol = -1;
+
+  // Compute the screen column of the start of the completed text.
+  // Use the cursor to get all wrapping and other settings right.
   col = curwin->w_cursor.col;
   curwin->w_cursor.col = compl_col;
   pum_display(compl_match_array, compl_match_arraysize, cur);
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 0d7e2f7b5d..8971b6d463 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -3045,12 +3045,13 @@ static int do_lock_var(lval_T *lp, char_u *name_end, int deep, int lock)
       li = li->li_next;
       ++lp->ll_n1;
     }
-  } else if (lp->ll_list != NULL)
-    /* (un)lock a List item. */
+  } else if (lp->ll_list != NULL) {
+    // (un)lock a List item.
     item_lock(&lp->ll_li->li_tv, deep, lock);
-  else
-    /* un(lock) a Dictionary item. */
+  } else {
+    // (un)lock a Dictionary item.
     item_lock(&lp->ll_di->di_tv, deep, lock);
+  }
 
   return ret;
 }
@@ -7337,7 +7338,7 @@ static struct fst {
   { "sqrt",              1, 1, f_sqrt },
   { "str2float",         1, 1, f_str2float },
   { "str2nr",            1, 2, f_str2nr },
-  { "strchars",          1, 1, f_strchars },
+  { "strchars",          1, 2, f_strchars },
   { "strdisplaywidth",   1, 2, f_strdisplaywidth },
   { "strftime",          1, 2, f_strftime },
   { "stridx",            2, 3, f_stridx },
@@ -10988,8 +10989,6 @@ static void f_has(typval_T *argvars, typval_T *rettv)
 #endif
     } else if (STRICMP(name, "syntax_items") == 0) {
       n = syntax_present(curwin);
-    } else if (STRICMP(name, "gui_running") == 0) {
-      n = ui_rgb_attached();
     }
   }
 
@@ -16215,13 +16214,23 @@ static void f_strlen(typval_T *argvars, typval_T *rettv)
 static void f_strchars(typval_T *argvars, typval_T *rettv)
 {
   char_u              *s = get_tv_string(&argvars[0]);
+  int skipcc = 0;
   varnumber_T len = 0;
+  int (*func_mb_ptr2char_adv)(char_u **pp);
 
-  while (*s != NUL) {
-    mb_cptr2char_adv(&s);
-    ++len;
+  if (argvars[1].v_type != VAR_UNKNOWN) {
+    skipcc = get_tv_number_chk(&argvars[1], NULL);
+  }
+  if (skipcc < 0 || skipcc > 1) {
+    EMSG(_(e_invarg));
+  } else {
+    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;
   }
-  rettv->vval.v_number = len;
 }
 
 /*
diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index a517037431..4d62dd0ff9 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -690,9 +690,17 @@ int do_move(linenr_T line1, linenr_T line2, linenr_T dest)
 {
   char_u      *str;
   linenr_T l;
-  linenr_T extra;           /* Num lines added before line1 */
-  linenr_T num_lines;       /* Num lines moved */
-  linenr_T last_line;       /* Last line in file after adding new text */
+  linenr_T extra;      // Num lines added before line1
+  linenr_T num_lines;  // Num lines moved
+  linenr_T last_line;  // Last line in file after adding new text
+
+  // Moving lines seems to corrupt the folds, delete folding info now
+  // and recreate it when finished.  Don't do this for manual folding, it
+  // would delete all folds.
+  bool isFolded = hasAnyFolding(curwin) && !foldmethodIsManual(curwin);
+  if (isFolded) {
+    deleteFoldRecurse(&curwin->w_folds);
+  }
 
   if (dest >= line1 && dest < line2) {
     EMSG(_("E134: Move lines into themselves"));
@@ -777,8 +785,14 @@ int do_move(linenr_T line1, linenr_T line2, linenr_T dest)
     if (dest > last_line + 1)
       dest = last_line + 1;
     changed_lines(line1, 0, dest, 0L);
-  } else
+  } else {
     changed_lines(dest + 1, 0, line1 + num_lines, 0L);
+  }
+
+  // recreate folds
+  if (isFolded) {
+    foldUpdateAll(curwin);
+  }
 
   return OK;
 }
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index c45be3de74..50513c0a6a 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -5659,8 +5659,13 @@ static void ex_quit(exarg_T *eap)
       || (only_one_window() && check_changed_any(eap->forceit))) {
     not_exiting();
   } else {
-    if (only_one_window()) {
-      // quit last window
+    // quit last window
+    // Note: only_one_window() returns true, even so a help window is
+    // still open. In that case only quit, if no address has been
+    // specified. Example:
+    // :h|wincmd w|1q     - don't quit
+    // :h|wincmd w|q      - quit
+    if (only_one_window() && (firstwin == lastwin || eap->addr_count == 0)) {
       getout(0);
     }
     /* close window; may free buffer */
@@ -8366,8 +8371,7 @@ makeopens (
 {
   int only_save_windows = TRUE;
   int nr;
-  int cnr = 1;
-  int restore_size = TRUE;
+  int restore_size = true;
   win_T       *wp;
   char_u      *sname;
   win_T       *edited_win = NULL;
@@ -8484,7 +8488,8 @@ makeopens (
   tab_firstwin = firstwin;      /* first window in tab page "tabnr" */
   tab_topframe = topframe;
   for (tabnr = 1;; ++tabnr) {
-    int need_tabnew = FALSE;
+    int need_tabnew = false;
+    int cnr = 1;
 
     if ((ssop_flags & SSOP_TABPAGES)) {
       tabpage_T *tp = find_tabpage(tabnr);
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 96bf2c78d2..d015f6b4a0 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -5136,6 +5136,8 @@ static int ex_window(void)
 
     /* Don't execute autocommands while deleting the window. */
     block_autocmds();
+    // Avoid command-line window first character being concealed
+    curwin->w_p_cole = 0;
     wp = curwin;
     bp = curbuf;
     win_goto(old_curwin);
diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index 8fe7ad0e30..383cd47dbe 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -1543,12 +1543,12 @@ rewind_retry:
       if (fileformat == EOL_UNKNOWN) {
         /* First try finding a NL, for Dos and Unix */
         if (try_dos || try_unix) {
-          for (p = ptr; p < ptr + size; ++p) {
-            // Reset the carriage return counter.
-            if (try_mac) {
-              try_mac = 1;
-            }
+          // Reset the carriage return counter.
+          if (try_mac) {
+            try_mac = 1;
+          }
 
+          for (p = ptr; p < ptr + size; ++p) {
             if (*p == NL) {
               if (!try_unix
                   || (try_dos && p > ptr && p[-1] == CAR))
diff --git a/src/nvim/fold.c b/src/nvim/fold.c
index 2e32e78062..6c135ef47b 100644
--- a/src/nvim/fold.c
+++ b/src/nvim/fold.c
@@ -767,9 +767,9 @@ void foldUpdate(win_T *wp, linenr_T top, linenr_T bot)
     return;
   }
 
-  /* Mark all folds from top to bot as maybe-small. */
-  (void)foldFind(&curwin->w_folds, top, &fp);
-  while (fp < (fold_T *)curwin->w_folds.ga_data + curwin->w_folds.ga_len
+  // Mark all folds from top to bot as maybe-small.
+  (void)foldFind(&wp->w_folds, top, &fp);
+  while (fp < (fold_T *)wp->w_folds.ga_data + wp->w_folds.ga_len
          && fp->fd_top < bot) {
     fp->fd_small = MAYBE;
     ++fp;
diff --git a/src/nvim/main.c b/src/nvim/main.c
index cef10d12d5..a8c2cebbbd 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -219,9 +219,10 @@ int main(int argc, char **argv)
 {
   argv0 = (char *)path_tail((char_u *)argv[0]);
 
-  char_u      *fname = NULL;            /* file name from command line */
-  mparm_T params;                       /* various parameters passed between
-                                         * main() and other functions. */
+  char_u *fname = NULL;   // file name from command line
+  mparm_T params;         // various parameters passed between
+                          // main() and other functions.
+  char_u *cwd = NULL;     // current workding dir on startup
   time_init();
 
   /* Many variables are in "params" so that we can pass them to invoked
@@ -461,11 +462,10 @@ int main(int argc, char **argv)
     TIME_MSG("jump to first error");
   }
 
-  /*
-   * If opened more than one window, start editing files in the other
-   * windows.
-   */
-  edit_buffers(&params);
+  // If opened more than one window, start editing files in the other
+  // windows.
+  edit_buffers(&params, cwd);
+  xfree(cwd);
 
   if (params.diff_mode) {
     /* set options in each window for "nvim -d". */
@@ -1182,12 +1182,19 @@ static char_u *get_fname(mparm_T *parmp)
    * Expand wildcards in file names.
    */
   if (!parmp->literal) {
-    /* Temporarily add '(' and ')' to 'isfname'.  These are valid
-     * filename characters but are excluded from 'isfname' to make
-     * "gf" work on a file name in parenthesis (e.g.: see vim.h). */
+    cwd = xmalloc(MAXPATHL);
+    if (cwd != NULL) {
+      os_dirname(cwd, MAXPATHL);
+    }
+    // Temporarily add '(' and ')' to 'isfname'.  These are valid
+    // filename characters but are excluded from 'isfname' to make
+    // "gf" work on a file name in parenthesis (e.g.: see vim.h).
     do_cmdline_cmd(":set isf+=(,)");
     alist_expand(NULL, 0);
     do_cmdline_cmd(":set isf&");
+    if (cwd != NULL) {
+      os_chdir((char *)cwd);
+    }
   }
 #endif
   return alist_name(&GARGLIST[0]);
@@ -1417,11 +1424,9 @@ static void create_windows(mparm_T *parmp)
   }
 }
 
-/*
- * If opened more than one window, start editing files in the other
- * windows.  make_windows() has already opened the windows.
- */
-static void edit_buffers(mparm_T *parmp)
+/// If opened more than one window, start editing files in the other
+/// windows. make_windows() has already opened the windows.
+static void edit_buffers(mparm_T *parmp, char_u *cwd)
 {
   int arg_idx;                          /* index in argument list */
   int i;
@@ -1442,7 +1447,10 @@ static void edit_buffers(mparm_T *parmp)
 
   arg_idx = 1;
   for (i = 1; i < parmp->window_count; ++i) {
-    /* When w_arg_idx is -1 remove the window (see create_windows()). */
+    if (cwd != NULL) {
+      os_chdir((char *)cwd);
+    }
+    // When w_arg_idx is -1 remove the window (see create_windows()).
     if (curwin->w_arg_idx == -1) {
       ++arg_idx;
       win_close(curwin, TRUE);
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index be8307e8b3..e036c49be4 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -6222,8 +6222,8 @@ void clear_tab_page_click_defs(StlClickDefinition *const tpcd,
         xfree(tpcd[i].func);
       }
     }
+    memset(tpcd, 0, (size_t) tpcd_size * sizeof(tpcd[0]));
   }
-  memset(tpcd, 0, (size_t) tpcd_size * sizeof(tpcd[0]));
 }
 
 void screenclear(void)
diff --git a/src/nvim/search.c b/src/nvim/search.c
index d393ee7d02..2dd0201259 100644
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -3076,18 +3076,18 @@ current_block (
   } else
     old_end = VIsual;
 
-  /*
-   * Search backwards for unclosed '(', '{', etc..
-   * Put this position in start_pos.
-   * Ignore quotes here.
-   */
+  // Search backwards for unclosed '(', '{', etc..
+  // Put this position in start_pos.
+  // Ignore quotes here.  Keep the "M" flag in 'cpo', as that is what the
+  // user wants.
   save_cpo = p_cpo;
-  p_cpo = (char_u *)"%";
+  p_cpo = (char_u *)(vim_strchr(p_cpo, CPO_MATCHBSL) != NULL ? "%M" : "%");
   while (count-- > 0) {
-    if ((pos = findmatch(NULL, what)) == NULL)
+    if ((pos = findmatch(NULL, what)) == NULL) {
       break;
+    }
     curwin->w_cursor = *pos;
-    start_pos = *pos;       /* the findmatch for end_pos will overwrite *pos */
+    start_pos = *pos;  // the findmatch for end_pos will overwrite *pos
   }
   p_cpo = save_cpo;
 
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index f47c5eadd3..494683d254 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -3004,14 +3004,19 @@ static void syn_cmd_spell(exarg_T *eap, int syncing)
     return;
 
   next = skiptowhite(arg);
-  if (STRNICMP(arg, "toplevel", 8) == 0 && next - arg == 8)
+  if (STRNICMP(arg, "toplevel", 8) == 0 && next - arg == 8) {
     curwin->w_s->b_syn_spell = SYNSPL_TOP;
-  else if (STRNICMP(arg, "notoplevel", 10) == 0 && next - arg == 10)
+  } else if (STRNICMP(arg, "notoplevel", 10) == 0 && next - arg == 10) {
     curwin->w_s->b_syn_spell = SYNSPL_NOTOP;
-  else if (STRNICMP(arg, "default", 7) == 0 && next - arg == 7)
+  } else if (STRNICMP(arg, "default", 7) == 0 && next - arg == 7) {
     curwin->w_s->b_syn_spell = SYNSPL_DEFAULT;
-  else
+  } else {
     EMSG2(_("E390: Illegal argument: %s"), arg);
+    return;
+  }
+
+  // assume spell checking changed, force a redraw
+  redraw_win_later(curwin, NOT_VALID);
 }
 
 /*
diff --git a/src/nvim/testdir/Makefile b/src/nvim/testdir/Makefile
index fe511166f2..d1a7abfbf7 100644
--- a/src/nvim/testdir/Makefile
+++ b/src/nvim/testdir/Makefile
@@ -15,7 +15,7 @@ SCRIPTS :=                                                             \
                                                            test30.out  \
                        test32.out              test34.out              \
            test36.out  test37.out                          test40.out  \
-                       test42.out                          test45.out  \
+                       test42.out                                      \
                        test47.out  test48.out  test49.out              \
                        test52.out  test53.out              test55.out  \
                                                test64.out              \
diff --git a/src/nvim/testdir/test13.in b/src/nvim/testdir/test13.in
index cb8a6fff89..6713f80e88 100644
--- a/src/nvim/testdir/test13.in
+++ b/src/nvim/testdir/test13.in
@@ -48,6 +48,12 @@ otestje3
 :au BufWipeout Xtestje1 buf Xtestje1
 :bwipe
 :w >>test.out
+:only
+:new|set buftype=help
+:wincmd w
+:1quit
+:$put ='Final line'
+:$w >>test.out
 :qa!
 ENDTEST
 
diff --git a/src/nvim/testdir/test13.ok b/src/nvim/testdir/test13.ok
index 0f1fc347a4..66ebce63f7 100644
--- a/src/nvim/testdir/test13.ok
+++ b/src/nvim/testdir/test13.ok
@@ -28,3 +28,4 @@ testje1
 	contents
 	contents
 end of testfile
+Final line
diff --git a/src/nvim/testdir/test30.in b/src/nvim/testdir/test30.in
index 3f7b9eb472..2a89eac73d 100644
--- a/src/nvim/testdir/test30.in
+++ b/src/nvim/testdir/test30.in
@@ -7,32 +7,27 @@ STARTTEST
 :" first write three test files, one in each format
 :set fileformat=unix
 :set fileformats=
-:/^1/w! XX1
-:/^2/w! XX2
-:/^3/w! XX3
-:/^4/w! XX4
-:/^5/w! XX5
-:/^6/w! XX6
-:/^7/w! XX7
-:/^8/w! XX8
-:/^9/w! XX9
-:/^10/w! XX10
 :/^unix/;/eof/-1w! XXUnix
 :/^dos/;/eof/-1w! XXDos
 :set bin noeol
 :$w! XXMac
+Gonoeol
+:$w! XXEol
 :set nobin eol
+:enew!
 :bwipe XXUnix XXDos XXMac
 :" create mixed format files
 :if has("win32")
 : !copy /b XXUnix+XXDos XXUxDs
 : !copy /b XXUnix+XXMac XXUxMac
 : !copy /b XXDos+XXMac XXDosMac
+: !copy /b XXMac+XXEol XXMacEol
 : !copy /b XXUnix+XXDos+XXMac XXUxDsMc
 :else
 : !cat XXUnix XXDos >XXUxDs
 : !cat XXUnix XXMac >XXUxMac
 : !cat XXDos XXMac >XXDosMac
+: !cat XXMac XXEol >XXMacEol
 : !cat XXUnix XXDos XXMac >XXUxDsMc
 :endif
 :"
@@ -97,26 +92,48 @@ STARTTEST
 :e! XXDosMac
 :w! XXtt53
 :bwipe XXDosMac
+:e! XXEol
+ggO=&ffs
+:=&ff
+:w! XXtt54
+:bwipe XXEol
 :set fileformats=dos,mac
 :e! XXUxDs
 :w! XXtt61
 :bwipe XXUxDs
 :e! XXUxMac
-:w! XXtt62
+ggO=&ffs
+:=&ff
+:w! XXtt62
 :bwipe XXUxMac
 :e! XXUxDsMc
 :w! XXtt63
 :bwipe XXUxDsMc
+:e! XXMacEol
+ggO=&ffs
+:=&ff
+:w! XXtt64
+:bwipe XXMacEol
 :"
 :" try reading and writing with 'fileformats' set to three formats
 :set fileformats=unix,dos,mac
 :e! XXUxDsMc
 :w! XXtt71
 :bwipe XXUxDsMc
+:e! XXEol
+ggO=&ffs
+:=&ff
+:w! XXtt72
+:bwipe XXEol
 :set fileformats=mac,dos,unix
 :e! XXUxDsMc
 :w! XXtt81
 :bwipe XXUxDsMc
+:e! XXEol
+ggO=&ffs
+:=&ff
+:w! XXtt82
+:bwipe XXEol
 :" try with 'binary' set
 :set fileformats=mac,unix,dos
 :set binary
@@ -150,11 +167,15 @@ ggdGaEND:w >>XXtt01
 :w >>XXtt51
 :w >>XXtt52
 :w >>XXtt53
+:w >>XXtt54
 :w >>XXtt61
 :w >>XXtt62
 :w >>XXtt63
+:w >>XXtt64
 :w >>XXtt71
+:w >>XXtt72
 :w >>XXtt81
+:w >>XXtt82
 :w >>XXtt91
 :w >>XXtt92
 :w >>XXtt93
@@ -181,11 +202,15 @@ Go4:$r XXtt41
 Go5:$r XXtt51
 :$r XXtt52
 :$r XXtt53
+:$r XXtt54
 Go6:$r XXtt61
 :$r XXtt62
 :$r XXtt63
+:$r XXtt64
 Go7:$r XXtt71
+:$r XXtt72
 Go8:$r XXtt81
+:$r XXtt82
 Go9:$r XXtt91
 :$r XXtt92
 :$r XXtt93
@@ -195,17 +220,6 @@ Go10:$r XXUnix
 :qa!
 ENDTEST
 
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-
 unix
 unix
 eof
diff --git a/src/nvim/testdir/test30.ok b/src/nvim/testdir/test30.ok
index 380ce67061..b35f4f5904 100644
--- a/src/nvim/testdir/test30.ok
+++ b/src/nvim/testdir/test30.ok
@@ -70,12 +70,16 @@ END
 dos
 dos
 mac
 mac
 END
+unix,mac:unix
+noeol
+END
 6
 unix
 unix
 dos
 dos
 END
+dos,mac:dos
 unix
 unix
 mac
 mac
@@ -86,6 +90,7 @@ dos
 dos
 mac
 mac
 END
+dos,mac:mac
+mac
+mac
+noeol
+END
 7
 unix
 unix
@@ -93,6 +98,9 @@ dos
 dos
 mac
 mac
 END
+unix,dos,mac:unix
+noeol
+END
 8
 unix
 unix
@@ -100,6 +108,7 @@ dos
 dos
 mac
 mac
 END
+mac,dos,unix:mac
+noeol
+END
 9
 unix
 unix
diff --git a/src/nvim/testdir/test45.in b/src/nvim/testdir/test45.in
deleted file mode 100644
index e5af5073d9..0000000000
--- a/src/nvim/testdir/test45.in
+++ /dev/null
@@ -1,80 +0,0 @@
-Tests for folding. vim: set ft=vim :
-
-STARTTEST
-:so small.vim
-:" We also need the +syntax feature here.
-:if !has("syntax")
-   e! test.ok
-   w! test.out
-   qa!
-:endif
-:" basic test if a fold can be created, opened, moving to the end and closed
-/^1
-zf2j:call append("$", "manual " . getline(foldclosed(".")))
-zo:call append("$", foldclosed("."))
-]z:call append("$", getline("."))
-zc:call append("$", getline(foldclosed(".")))
-:" test folding with markers.
-:set fdm=marker fdl=1 fdc=3
-/^5
-:call append("$", "marker " . foldlevel("."))
-[z:call append("$", foldlevel("."))
-jo{{ r{jj:call append("$", foldlevel("."))
-kYpj:call append("$", foldlevel("."))
-:" test folding with indent
-:set fdm=indent sw=2
-/^2 b
-i  jI    :call append("$", "indent " . foldlevel("."))
-k:call append("$", foldlevel("."))
-:" test syntax folding
-:set fdm=syntax fdl=0
-:syn region Hup start="dd" end="ii" fold contains=Fd1,Fd2,Fd3
-:syn region Fd1 start="ee" end="ff" fold contained
-:syn region Fd2 start="gg" end="hh" fold contained
-:syn region Fd3 start="commentstart" end="commentend" fold contained
-Gzk:call append("$", "folding " . getline("."))
-k:call append("$", getline("."))
-jAcommentstart  Acommentend:set fdl=1
-3j:call append("$", getline("."))
-:set fdl=0
-zOj:call append("$", getline("."))
-:" test expression folding
-:fun Flvl()
-  let l = getline(v:lnum)
-  if l =~ "bb$"
-    return 2
-  elseif l =~ "gg$"
-    return "s1"
-  elseif l =~ "ii$"
-    return ">2"
-  elseif l =~ "kk$"
-    return "0"
-  endif
-  return "="
-endfun
-:set fdm=expr fde=Flvl()
-/bb$
-:call append("$", "expr " . foldlevel("."))
-/hh$
-:call append("$", foldlevel("."))
-/ii$
-:call append("$", foldlevel("."))
-/kk$
-:call append("$", foldlevel("."))
-:/^last/+1,$w! test.out
-:delfun Flvl
-:qa!
-ENDTEST
-
-1 aa
-2 bb
-3 cc
-4 dd {{{
-5 ee {{{ }}}
-6 ff }}}
-7 gg
-8 hh
-9 ii
-a jj
-b kk
-last
diff --git a/src/nvim/testdir/test45.ok b/src/nvim/testdir/test45.ok
deleted file mode 100644
index f04996e337..0000000000
--- a/src/nvim/testdir/test45.ok
+++ /dev/null
@@ -1,18 +0,0 @@
-manual 1 aa
--1
-3 cc
-1 aa
-marker 2
-1
-1
-0
-indent 2
-1
-folding 9 ii
-    3 cc
-7 gg
-8 hh
-expr 2
-1
-2
-0
diff --git a/src/nvim/testdir/test47.in b/src/nvim/testdir/test47.in
index 13ad82462f..f15eaf0f8f 100644
--- a/src/nvim/testdir/test47.in
+++ b/src/nvim/testdir/test47.in
@@ -1,5 +1,7 @@
 Tests for vertical splits and filler lines in diff mode
 
+Also tests restoration of saved options by :diffoff.
+
 STARTTEST
 :so small.vim
 :" Disable the title to avoid xterm keeping the wrong one.
@@ -10,8 +12,19 @@ pkdd:w! Xtest
 ddGpkkrXoxxx:w! Xtest2
 :file Nop
 ggoyyyjjjozzzz
+:set foldmethod=marker foldcolumn=4
+:redir => nodiffsettings
+:silent! :set diff? fdm? fdc? scb? crb? wrap?
+:redir END
 :vert diffsplit Xtest
 :vert diffsplit Xtest2
+:redir => diffsettings
+:silent! :set diff? fdm? fdc? scb? crb? wrap?
+:redir END
+:let diff_fdm = &fdm
+:let diff_fdc = &fdc
+:" repeat entering diff mode here to see if this saves the wrong settings
+:diffthis
 :" jump to second window for a moment to have filler line appear at start of
 :" first window
 ggpgg:let one = winline()
@@ -36,8 +49,36 @@ j:let three = three . "-" . winline()
 :call append("$", two)
 :call append("$", three)
 :$-2,$w! test.out
-:" Test that diffing shows correct filler lines
+:"
+:" Test diffoff
 :diffoff!
+1
+:let &diff = 1
+:let &fdm = diff_fdm
+:let &fdc = diff_fdc
+4
+:diffoff!
+:$put =nodiffsettings
+:$put =diffsettings
+1
+:redir => nd1
+:silent! :set diff? fdm? fdc? scb? crb? wrap?
+:redir END
+
+:redir => nd2
+:silent! :set diff? fdm? fdc? scb? crb? wrap?
+:redir END
+
+:redir => nd3
+:silent! :set diff? fdm? fdc? scb? crb? wrap?
+:redir END
+
+:$put =nd1
+:$put =nd2
+:$put =nd3
+:$-39,$w >> test.out
+:"
+:" Test that diffing shows correct filler lines
 :windo :bw!
 :enew
 :put =range(4,10)
@@ -51,7 +92,7 @@ j:let three = three . "-" . winline()
 :enew
 :put =w0
 :.w >> test.out
-:unlet! one two three w0
+:unlet! one two three nodiffsettings diffsettings diff_fdm diff_fdc nd1 nd2 nd3 w0
 :qa!
 ENDTEST
 
diff --git a/src/nvim/testdir/test47.ok b/src/nvim/testdir/test47.ok
index b1cba92b1c..83e96571ad 100644
--- a/src/nvim/testdir/test47.ok
+++ b/src/nvim/testdir/test47.ok
@@ -1,4 +1,44 @@
 2-4-5-6-8-9
 1-2-4-5-8
 2-3-4-5-6-7-8
+
+
+nodiff
+  foldmethod=marker
+  foldcolumn=4
+noscrollbind
+nocursorbind
+  wrap
+
+
+  diff
+  foldmethod=diff
+  foldcolumn=2
+  scrollbind
+  cursorbind
+nowrap
+
+
+nodiff
+  foldmethod=marker
+  foldcolumn=4
+noscrollbind
+nocursorbind
+  wrap
+
+
+nodiff
+  foldmethod=marker
+  foldcolumn=4
+noscrollbind
+nocursorbind
+  wrap
+
+
+nodiff
+  foldmethod=marker
+  foldcolumn=4
+noscrollbind
+nocursorbind
+  wrap
 1
diff --git a/src/nvim/version.c b/src/nvim/version.c
index 2225611779..3fb1738f2a 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -487,7 +487,7 @@ static int included_patches[] = {
   // 804,
   803,
   802,
-  // 801,
+  801,
   800,
   799,
   798,
@@ -519,8 +519,8 @@ static int included_patches[] = {
   // 772 NA
   // 771,
   // 770 NA
-  // 769,
-  // 768,
+  769,
+  768,
   // 767,
   // 766 NA
   765,
@@ -528,12 +528,12 @@ static int included_patches[] = {
   // 763 NA
   // 762 NA
   // 761 NA
-  // 760,
+  760,
   // 759 NA
-  // 758,
+  758,
   // 757 NA
   // 756 NA
-  // 755,
+  755,
   754,
   753,
   // 752,
@@ -548,7 +548,7 @@ static int included_patches[] = {
   // 743,
   // 742,
   741,
-  // 740,
+  740,
   739,
   // 738 NA
   // 737,
@@ -588,19 +588,19 @@ static int included_patches[] = {
   // 703 NA
   702,
   // 701 NA
-  // 700,
+  700,
   699,
   698,
   697,
   696,
   695,
-  // 694,
-  // 693,
+  694,
+  693,
   // 692 NA
   // 691 NA
   690,
-  // 689,
-  // 688,
+  689,
+  688,
   // 687 NA
   686,
   685,
@@ -626,7 +626,7 @@ static int included_patches[] = {
   665,
   // 664 NA
   // 663 NA
-  // 662,
+  662,
   // 661 NA
   660,
   659,
@@ -645,7 +645,7 @@ static int included_patches[] = {
   646,
   645,
   // 644 NA
-  // 643,
+  643,
   642,
   // 641 NA
   640,