1 files changed, 259 insertions, 206 deletions

diff --git a/src/nvim/window.c b/src/nvim/window.c
index b71b2cb603..bea55c465f 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -1,12 +1,3 @@
-/*
- * VIM - Vi IMproved	by Bram Moolenaar
- *
- * Do ":help uganda"  in Vim to read a list of people who contributed.
- * Do ":help credits" in Vim to see a list of people who contributed.
- * See README.txt for an overview of the Vim source code.
- */
-
-#include <errno.h>
 #include <assert.h>
 #include <inttypes.h>
 #include <stdbool.h>
@@ -106,7 +97,7 @@ do_window (
      * don't replicate the quickfix buffer. */
     if (bt_quickfix(curbuf))
       goto newwindow;
-    win_split((int)Prenum, 0);
+    (void)win_split((int)Prenum, 0);
     break;
 
   /* split current window in two parts, vertically */
@@ -117,7 +108,7 @@ do_window (
      * don't replicate the quickfix buffer. */
     if (bt_quickfix(curbuf))
       goto newwindow;
-    win_split((int)Prenum, WSP_VERT);
+    (void)win_split((int)Prenum, WSP_VERT);
     break;
 
   /* split current window and edit alternate file */
@@ -257,7 +248,7 @@ newwindow:
       /* First create a new tab with the window, then go back to
        * the old tab and close the window there. */
       wp = curwin;
-      if (win_new_tabpage((int)Prenum) == OK
+      if (win_new_tabpage((int)Prenum, NULL) == OK
           && valid_tabpage(oldtab)) {
         newtab = curtab;
         goto_tabpage_tp(oldtab, TRUE, TRUE);
@@ -1053,19 +1044,21 @@ static void win_init_some(win_T *newp, win_T *oldp)
 }
 
 
-/*
- * Check if "win" is a pointer to an existing window.
- */
-int win_valid(win_T *win)
+/// Check if "win" is a pointer to an existing window in the current tabpage.
+///
+/// @param  win  window to check
+bool win_valid(win_T *win) FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
 {
-  if (win == NULL)
-    return FALSE;
+  if (win == NULL) {
+    return false;
+  }
+
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
     if (wp == win) {
-      return TRUE;
+      return true;
     }
   }
-  return FALSE;
+  return false;
 }
 
 /*
@@ -1741,21 +1734,18 @@ close_windows (
     shell_new_rows();
 }
 
-/*
- * Return TRUE if the current window is the only window that exists (ignoring
- * "aucmd_win").
- * Returns FALSE if there is a window, possibly in another tab page.
- */
-static int last_window(void)
+/// Check that current window is the last one.
+///
+/// @return true if the current window is the only window that exists, false if
+///         there is another, possibly in another tab page.
+static bool last_window(void) FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
 {
   return one_window() && first_tabpage->tp_next == NULL;
 }
 
-/*
- * Return TRUE if there is only one window other than "aucmd_win" in the
- * current tab page.
- */
-bool one_window(void)
+/// Check that current tab page contains no more then one window other than
+/// "aucmd_win".
+bool one_window(void) FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
 {
   bool seen_one = false;
 
@@ -1770,14 +1760,20 @@ bool one_window(void)
   return true;
 }
 
-/*
- * Close the possibly last window in a tab page.
- * Returns TRUE when the window was closed already.
- */
-static int close_last_window_tabpage(win_T *win, int free_buf, tabpage_T *prev_curtab)
+/// Close the possibly last window in a tab page.
+///
+/// @param  win          window to close
+/// @param  free_buf     whether to free the window's current buffer
+/// @param  prev_curtab  previous tabpage that will be closed if "win" is the
+///                      last window in the tabpage
+///
+/// @return true when the window was closed already.
+static bool close_last_window_tabpage(win_T *win, bool free_buf,
+                                      tabpage_T *prev_curtab)
+  FUNC_ATTR_NONNULL_ARG(1)
 {
   if (firstwin != lastwin) {
-    return FALSE;
+    return false;
   }
   buf_T   *old_curbuf = curbuf;
 
@@ -1818,14 +1814,15 @@ static int close_last_window_tabpage(win_T *win, int free_buf, tabpage_T *prev_c
     terminal_resize(term, 0, 0);
   }
 
-  /* Since goto_tabpage_tp above did not trigger *Enter autocommands, do
-   * that now. */
-  apply_autocmds(EVENT_TABCLOSED, prev_idx, prev_idx, FALSE, curbuf);
-  apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
-  apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
-  if (old_curbuf != curbuf)
-    apply_autocmds(EVENT_BUFENTER, NULL, NULL, FALSE, curbuf);
-  return TRUE;
+  // Since goto_tabpage_tp above did not trigger *Enter autocommands, do
+  // that now.
+  apply_autocmds(EVENT_TABCLOSED, prev_idx, prev_idx, false, curbuf);
+  apply_autocmds(EVENT_WINENTER, NULL, NULL, false, curbuf);
+  apply_autocmds(EVENT_TABENTER, NULL, NULL, false, curbuf);
+  if (old_curbuf != curbuf) {
+    apply_autocmds(EVENT_BUFENTER, NULL, NULL, false, curbuf);
+  }
+  return true;
 }
 
 /*
@@ -1916,9 +1913,16 @@ int win_close(win_T *win, int free_buf)
    */
   if (win->w_buffer != NULL) {
     win->w_closing = true;
-    close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0, TRUE);
-    if (win_valid(win))
+    close_buffer(win, win->w_buffer, free_buf ? DOBUF_UNLOAD : 0, true);
+    if (win_valid(win)) {
       win->w_closing = false;
+    }
+
+    // Make sure curbuf is valid. It can become invalid if 'bufhidden' is
+    // "wipe".
+    if (!buf_valid(curbuf)) {
+      curbuf = firstbuf;
+    }
   }
 
   if (only_one_window() && win_valid(win) && win->w_buffer == NULL
@@ -2310,20 +2314,22 @@ static win_T *frame2win(frame_T *frp)
   return frp->fr_win;
 }
 
-/*
- * Return TRUE if frame "frp" contains window "wp".
- */
-static int frame_has_win(frame_T *frp, win_T *wp)
+/// Check that the frame "frp" contains the window "wp".
+///
+/// @param  frp  frame
+/// @param  wp   window
+static bool frame_has_win(frame_T *frp, win_T *wp)
+  FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ARG(1)
 {
-  frame_T     *p;
-
-  if (frp->fr_layout == FR_LEAF)
+  if (frp->fr_layout == FR_LEAF) {
     return frp->fr_win == wp;
-
-  for (p = frp->fr_child; p != NULL; p = p->fr_next)
-    if (frame_has_win(p, wp))
-      return TRUE;
-  return FALSE;
+  }
+  for (frame_T *p = frp->fr_child; p != NULL; p = p->fr_next) {
+    if (frame_has_win(p, wp)) {
+      return true;
+    }
+  }
+  return false;
 }
 
 /*
@@ -2415,58 +2421,72 @@ frame_new_height (
   topfrp->fr_height = height;
 }
 
-/*
- * Return TRUE if height of frame "frp" should not be changed because of
- * the 'winfixheight' option.
- */
-static int frame_fixed_height(frame_T *frp)
+/// Return true if height of frame "frp" should not be changed because of
+/// the 'winfixheight' option.
+///
+/// @param  frp  frame
+///
+/// @return true if the frame has a fixed height
+static bool frame_fixed_height(frame_T *frp)
+  FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL
 {
-  /* frame with one window: fixed height if 'winfixheight' set. */
-  if (frp->fr_win != NULL)
+  // frame with one window: fixed height if 'winfixheight' set.
+  if (frp->fr_win != NULL) {
     return frp->fr_win->w_p_wfh;
-
+  }
   if (frp->fr_layout == FR_ROW) {
-    /* The frame is fixed height if one of the frames in the row is fixed
-     * height. */
-    for (frp = frp->fr_child; frp != NULL; frp = frp->fr_next)
-      if (frame_fixed_height(frp))
-        return TRUE;
-    return FALSE;
+    // The frame is fixed height if one of the frames in the row is fixed
+    // height.
+    for (frp = frp->fr_child; frp != NULL; frp = frp->fr_next) {
+      if (frame_fixed_height(frp)) {
+        return true;
+      }
+    }
+    return false;
   }
 
-  /* frp->fr_layout == FR_COL: The frame is fixed height if all of the
-   * frames in the row are fixed height. */
-  for (frp = frp->fr_child; frp != NULL; frp = frp->fr_next)
-    if (!frame_fixed_height(frp))
-      return FALSE;
-  return TRUE;
+  // frp->fr_layout == FR_COL: The frame is fixed height if all of the
+  // frames in the row are fixed height.
+  for (frp = frp->fr_child; frp != NULL; frp = frp->fr_next) {
+    if (!frame_fixed_height(frp)) {
+      return false;
+    }
+  }
+  return true;
 }
 
-/*
- * Return TRUE if width of frame "frp" should not be changed because of
- * the 'winfixwidth' option.
- */
-static int frame_fixed_width(frame_T *frp)
+/// Return true if width of frame "frp" should not be changed because of
+/// the 'winfixwidth' option.
+///
+/// @param  frp  frame
+///
+/// @return true if the frame has a fixed width
+static bool frame_fixed_width(frame_T *frp)
+  FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL
 {
-  /* frame with one window: fixed width if 'winfixwidth' set. */
-  if (frp->fr_win != NULL)
+  // frame with one window: fixed width if 'winfixwidth' set.
+  if (frp->fr_win != NULL) {
     return frp->fr_win->w_p_wfw;
-
+  }
   if (frp->fr_layout == FR_COL) {
-    /* The frame is fixed width if one of the frames in the row is fixed
-     * width. */
-    for (frp = frp->fr_child; frp != NULL; frp = frp->fr_next)
-      if (frame_fixed_width(frp))
-        return TRUE;
-    return FALSE;
+    // The frame is fixed width if one of the frames in the row is fixed
+    // width.
+    for (frp = frp->fr_child; frp != NULL; frp = frp->fr_next) {
+      if (frame_fixed_width(frp)) {
+        return true;
+      }
+    }
+    return false;
   }
 
-  /* frp->fr_layout == FR_ROW: The frame is fixed width if all of the
-   * frames in the row are fixed width. */
-  for (frp = frp->fr_child; frp != NULL; frp = frp->fr_next)
-    if (!frame_fixed_width(frp))
-      return FALSE;
-  return TRUE;
+  // frp->fr_layout == FR_ROW: The frame is fixed width if all of the
+  // frames in the row are fixed width.
+  for (frp = frp->fr_child; frp != NULL; frp = frp->fr_next) {
+    if (!frame_fixed_width(frp)) {
+      return false;
+    }
+  }
+  return true;
 }
 
 /*
@@ -2928,18 +2948,19 @@ void free_tabpage(tabpage_T *tp)
   unref_var_dict(tp->tp_vars);
 
 
-
+  xfree(tp->localdir);  // Free tab-local working directory
   xfree(tp);
 }
 
-/*
- * Create a new Tab page with one window.
- * It will edit the current buffer, like after ":split".
- * When "after" is 0 put it just after the current Tab page.
- * Otherwise put it just before tab page "after".
- * Return FAIL or OK.
- */
-int win_new_tabpage(int after)
+/// Create a new tabpage with one window.
+///
+/// It will edit the current buffer, like after :split.
+///
+/// @param after Put new tabpage after tabpage "after", or after the current
+///              tabpage in case of 0.
+/// @param filename Will be passed to apply_autocmds().
+/// @return Was the new tabpage created successfully? FAIL or OK.
+int win_new_tabpage(int after, char_u *filename)
 {
   tabpage_T   *tp = curtab;
   tabpage_T   *newtp;
@@ -2979,10 +3000,12 @@ int win_new_tabpage(int after)
     newtp->tp_topframe = topframe;
     last_status(FALSE);
 
-
     redraw_all_later(CLEAR);
-    apply_autocmds(EVENT_WINENTER, NULL, NULL, FALSE, curbuf);
-    apply_autocmds(EVENT_TABENTER, NULL, NULL, FALSE, curbuf);
+
+    apply_autocmds(EVENT_TABNEW, filename, filename, false, curbuf);
+    apply_autocmds(EVENT_WINENTER, NULL, NULL, false, curbuf);
+    apply_autocmds(EVENT_TABENTER, NULL, NULL, false, curbuf);
+
     return OK;
   }
 
@@ -3003,7 +3026,7 @@ int may_open_tabpage(void)
   if (n != 0) {
     cmdmod.tab = 0;         /* reset it to avoid doing it twice */
     postponed_split_tab = 0;
-    return win_new_tabpage(n);
+    return win_new_tabpage(n, NULL);
   }
   return FAIL;
 }
@@ -3027,9 +3050,11 @@ int make_tabpages(int maxcount)
    */
   block_autocmds();
 
-  for (todo = count - 1; todo > 0; --todo)
-    if (win_new_tabpage(0) == FAIL)
+  for (todo = count - 1; todo > 0; --todo) {
+    if (win_new_tabpage(0, NULL) == FAIL) {
       break;
+    }
+  }
 
   unblock_autocmds();
 
@@ -3037,10 +3062,10 @@ int make_tabpages(int maxcount)
   return count - todo;
 }
 
-/*
- * Return TRUE when "tpc" points to a valid tab page.
- */
-bool valid_tabpage(tabpage_T *tpc)
+/// Check that tpc points to a valid tab page.
+///
+/// @param[in]  tpc  Tabpage to check.
+bool valid_tabpage(tabpage_T *tpc) FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
 {
   FOR_ALL_TABS(tp) {
     if (tp == tpc) {
@@ -3261,17 +3286,27 @@ void goto_tabpage_win(tabpage_T *tp, win_T *wp)
   }
 }
 
-/*
- * Move the current tab page to before tab page "nr".
- */
+// Move the current tab page to after tab page "nr".
 void tabpage_move(int nr)
 {
-  int n = nr;
-  tabpage_T   *tp;
+  int n = 1;
+  tabpage_T *tp;
+  tabpage_T *tp_dst;
 
   if (first_tabpage->tp_next == NULL)
     return;
 
+  for (tp = first_tabpage; tp->tp_next != NULL && n < nr; tp = tp->tp_next) {
+    ++n;
+  }
+
+  if (tp == curtab || (nr > 0 && tp->tp_next != NULL
+                       && tp->tp_next == curtab)) {
+    return;
+  }
+
+  tp_dst = tp;
+
   /* Remove the current tab page from the list of tab pages. */
   if (curtab == first_tabpage)
     first_tabpage = curtab->tp_next;
@@ -3284,15 +3319,13 @@ void tabpage_move(int nr)
     tp->tp_next = curtab->tp_next;
   }
 
-  /* Re-insert it at the specified position. */
-  if (n <= 0) {
+  // Re-insert it at the specified position.
+  if (nr <= 0) {
     curtab->tp_next = first_tabpage;
     first_tabpage = curtab;
   } else {
-    for (tp = first_tabpage; tp->tp_next != NULL && n > 1; tp = tp->tp_next)
-      --n;
-    curtab->tp_next = tp->tp_next;
-    tp->tp_next = curtab;
+    curtab->tp_next = tp_dst->tp_next;
+    tp_dst->tp_next = curtab;
   }
 
   /* Need to redraw the tabline.  Tab page contents doesn't change. */
@@ -3527,18 +3560,24 @@ static void win_enter_ext(win_T *wp, bool undo_sync, int curwin_invalid, int tri
     curwin->w_cursor.coladd = 0;
   changed_line_abv_curs();      /* assume cursor position needs updating */
 
-  if (curwin->w_localdir != NULL) {
-    /* Window has a local directory: Save current directory as global
-     * directory (unless that was done already) and change to the local
-     * directory. */
+  // The new directory is either the local directory of the window, of the tab
+  // or NULL.
+  char_u *new_dir = curwin->w_localdir ? curwin->w_localdir : curtab->localdir;
+
+  if (new_dir) {
+    // Window/tab has a local directory: Save current directory as global
+    // directory (unless that was done already) and change to the local
+    // directory.
     if (globaldir == NULL) {
       char_u cwd[MAXPATHL];
 
-      if (os_dirname(cwd, MAXPATHL) == OK)
+      if (os_dirname(cwd, MAXPATHL) == OK) {
         globaldir = vim_strsave(cwd);
+      }
+    }
+    if (os_chdir((char *)new_dir) == 0) {
+      shorten_fnames(true);
     }
-    if (os_chdir((char *)curwin->w_localdir) == 0)
-      shorten_fnames(TRUE);
   } else if (globaldir != NULL) {
     /* Window doesn't have a local directory and we are not in the global
      * directory: Change to the global directory. */
@@ -4547,10 +4586,19 @@ void win_drag_vsep_line(win_T *dragwin, int offset)
   }
   assert(fr);
 
-  if (room < offset)            /* Not enough room */
-    offset = room;              /* Move as far as we can */
-  if (offset <= 0)              /* No room at all, quit. */
+  // Not enough room
+  if (room < offset) {
+    offset = room;  // Move as far as we can
+  }
+
+  // No room at all, quit.
+  if (offset <= 0) {
     return;
+  }
+
+  if (fr == NULL) {
+    return;  // Safety check, should not happen.
+  }
 
   /* grow frame fr by offset lines */
   frame_new_width(fr, fr->fr_width + offset, left, FALSE);
@@ -4582,10 +4630,8 @@ void win_drag_vsep_line(win_T *dragwin, int offset)
 
 #define FRACTION_MULT   16384L
 
-/*
- * Set wp->w_fraction for the current w_wrow and w_height.
- */
-static void set_fraction(win_T *wp)
+// Set wp->w_fraction for the current w_wrow and w_height.
+void set_fraction(win_T *wp)
 {
   wp->w_fraction = ((long)wp->w_wrow * FRACTION_MULT + wp->w_height / 2)
                    / (long)wp->w_height;
@@ -4846,17 +4892,15 @@ static void frame_add_height(frame_T *frp, int n)
  */
 char_u *grab_file_name(long count, linenr_T *file_lnum)
 {
+  int options = FNAME_MESS | FNAME_EXP | FNAME_REL | FNAME_UNESC;
   if (VIsual_active) {
     size_t len;
     char_u  *ptr;
     if (get_visual_text(NULL, &ptr, &len) == FAIL)
       return NULL;
-    return find_file_name_in_path(ptr, len,
-                                  FNAME_MESS|FNAME_EXP|FNAME_REL,
-                                  count, curbuf->b_ffname);
+    return find_file_name_in_path(ptr, len, options, count, curbuf->b_ffname);
   }
-  return file_name_at_cursor(FNAME_MESS|FNAME_HYP|FNAME_EXP|FNAME_REL, count,
-                             file_lnum);
+  return file_name_at_cursor(options | FNAME_HYP, count, file_lnum);
 }
 
 /*
@@ -4927,12 +4971,18 @@ file_name_in_line (
    * Also allow "://" when ':' is not in 'isfname'.
    */
   len = 0;
-  while (vim_isfilec(ptr[len])
-         || ((options & FNAME_HYP) && path_is_url((char *)ptr + len)))
-    if (has_mbyte)
+  while (vim_isfilec(ptr[len]) || (ptr[len] == '\\' && ptr[len + 1] == ' ')
+         || ((options & FNAME_HYP) && path_is_url((char *)ptr + len))) {
+    if (ptr[len] == '\\' && ptr[len + 1] == ' ') {
+      // Skip over the "\" in "\ ".
+      ++len;
+    }
+    if (has_mbyte) {
       len += (size_t)(*mb_ptr2len)(ptr + len);
-    else
+    } else {
       ++len;
+    }
+  }
 
   /*
    * If there is trailing punctuation, remove it.
@@ -5057,27 +5107,22 @@ int min_rows(void)
   return total;
 }
 
-/*
- * Return TRUE if there is only one window (in the current tab page), not
- * counting a help or preview window, unless it is the current window.
- * Does not count "aucmd_win".
- */
-int only_one_window(void)
+/// Check that there is only one window (and only one tab page), not counting a
+/// help or preview window, unless it is the current window. Does not count
+/// "aucmd_win".
+bool only_one_window(void) FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT
 {
-  int count = 0;
-
-  /* If there is another tab page there always is another window. */
-  if (first_tabpage->tp_next != NULL)
-    return FALSE;
+  // If there is another tab page there always is another window.
+  if (first_tabpage->tp_next != NULL) {
+    return false;
+  }
 
+  int count = 0;
   FOR_ALL_WINDOWS_IN_TAB(wp, curtab) {
     if (wp->w_buffer != NULL
         && (!((wp->w_buffer->b_help && !curbuf->b_help)
-              || wp->w_p_pvw
-              ) || wp == curwin)
-        && wp != aucmd_win
-        ) {
-      ++count;
+              || wp->w_p_pvw) || wp == curwin) && wp != aucmd_win) {
+      count++;
     }
   }
   return count <= 1;
@@ -5315,14 +5360,14 @@ void restore_buffer(buf_T *save_curbuf)
 }
 
 
-/*
- * Add match to the match list of window 'wp'.  The pattern 'pat' will be
- * highlighted with the group 'grp' with priority 'prio'.
- * Optionally, a desired ID 'id' can be specified (greater than or equal to 1).
- * If no particular ID is desired, -1 must be specified for 'id'.
- * Return ID of added match, -1 on failure.
- */
-int match_add(win_T *wp, char_u *grp, char_u *pat, int prio, int id, list_T *pos_list)
+// Add match to the match list of window 'wp'.  The pattern 'pat' will be
+// highlighted with the group 'grp' with priority 'prio'.
+// Optionally, a desired ID 'id' can be specified (greater than or equal to 1).
+// If no particular ID is desired, -1 must be specified for 'id'.
+// Return ID of added match, -1 on failure.
+int match_add(win_T *wp, char_u *grp, char_u *pat,
+              int prio, int id, list_T *pos_list,
+              char_u *conceal_char)
 {
   matchitem_T *cur;
   matchitem_T *prev;
@@ -5378,6 +5423,10 @@ int match_add(win_T *wp, char_u *grp, char_u *pat, int prio, int id, list_T *pos
   m->match.regprog = regprog;
   m->match.rmm_ic = FALSE;
   m->match.rmm_maxcol = 0;
+  m->conceal_char = 0;
+  if (conceal_char != NULL) {
+    m->conceal_char = (*mb_ptr2char)(conceal_char);
+  }
 
   // Set up position matches
   if (pos_list != NULL)
@@ -5576,38 +5625,42 @@ matchitem_T *get_match(win_T *wp, int id)
 }
 
 
-/*
- * Return TRUE if "topfrp" and its children are at the right height.
- */
-static int frame_check_height(frame_T *topfrp, int height)
+/// Check that "topfrp" and its children are at the right height.
+///
+/// @param  topfrp  top frame pointer
+/// @param  height  expected height
+static bool frame_check_height(frame_T *topfrp, int height)
+  FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL
 {
-  frame_T *frp;
-
-  if (topfrp->fr_height != height)
-    return FALSE;
-
-  if (topfrp->fr_layout == FR_ROW)
-    for (frp = topfrp->fr_child; frp != NULL; frp = frp->fr_next)
-      if (frp->fr_height != height)
-        return FALSE;
-
-  return TRUE;
+  if (topfrp->fr_height != height) {
+    return false;
+  }
+  if (topfrp->fr_layout == FR_ROW) {
+    for (frame_T *frp = topfrp->fr_child; frp != NULL; frp = frp->fr_next) {
+      if (frp->fr_height != height) {
+        return false;
+      }
+    }
+  }
+  return true;
 }
 
-/*
- * Return TRUE if "topfrp" and its children are at the right width.
- */
-static int frame_check_width(frame_T *topfrp, int width)
+/// Check that "topfrp" and its children are at the right width.
+///
+/// @param  topfrp  top frame pointer
+/// @param  width   expected width
+static bool frame_check_width(frame_T *topfrp, int width)
+  FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL
 {
-  frame_T *frp;
-
-  if (topfrp->fr_width != width)
-    return FALSE;
-
-  if (topfrp->fr_layout == FR_COL)
-    for (frp = topfrp->fr_child; frp != NULL; frp = frp->fr_next)
-      if (frp->fr_width != width)
-        return FALSE;
-
-  return TRUE;
+  if (topfrp->fr_width != width) {
+    return false;
+  }
+  if (topfrp->fr_layout == FR_COL) {
+    for (frame_T *frp = topfrp->fr_child; frp != NULL; frp = frp->fr_next) {
+      if (frp->fr_width != width) {
+        return false;
+      }
+    }
+  }
+  return true;
 }