refactor: follow style guide

- reduce variable scope
- prefer initialization over declaration and assignment
- use bool to represent boolean values

42 files changed, 287 insertions, 554 deletions

diff --git a/src/nvim/arglist.c b/src/nvim/arglist.c
index 7f75506c1e..433032fbf9 100644
--- a/src/nvim/arglist.c
+++ b/src/nvim/arglist.c
@@ -254,9 +254,8 @@ void alist_slash_adjust(void)
 static char *do_one_arg(char *str)
 {
   char *p;
-  bool inbacktick;
 
-  inbacktick = false;
+  bool inbacktick = false;
   for (p = str; *str; str++) {
     // When the backslash is used for escaping the special meaning of a
     // character we need to keep it until wildcard expansion.
@@ -834,10 +833,8 @@ char *get_arglist_name(expand_T *xp FUNC_ATTR_UNUSED, int idx)
 /// Get the file name for an argument list entry.
 char *alist_name(aentry_T *aep)
 {
-  buf_T *bp;
-
   // Use the name from the associated buffer if it exists.
-  bp = buflist_findnr(aep->ae_fnum);
+  buf_T *bp = buflist_findnr(aep->ae_fnum);
   if (bp == NULL || bp->b_fname == NULL) {
     return aep->ae_fname;
   }
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 677809459c..230cd4cef7 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -134,13 +134,12 @@ int get_highest_fnum(void)
 static int read_buffer(int read_stdin, exarg_T *eap, int flags)
 {
   int retval = OK;
-  linenr_T line_count;
   bool silent = shortmess(SHM_FILEINFO);
 
   // Read from the buffer which the text is already filled in and append at
   // the end.  This makes it possible to retry when 'fileformat' or
   // 'fileencoding' was guessed wrong.
-  line_count = curbuf->b_ml.ml_line_count;
+  linenr_T line_count = curbuf->b_ml.ml_line_count;
   retval = readfile(read_stdin ? NULL : curbuf->b_ffname,
                     read_stdin ? NULL : curbuf->b_fname,
                     line_count, 0, (linenr_T)MAXLNUM, eap,
@@ -1039,9 +1038,8 @@ char *do_bufdel(int command, char *arg, int addr_count, int start_bnr, int end_b
 {
   int do_current = 0;             // delete current buffer?
   int deleted = 0;                // number of buffers deleted
-  char *errormsg = NULL;   // return value
+  char *errormsg = NULL;          // return value
   int bnr;                        // buffer number
-  char *p;
 
   if (addr_count == 0) {
     (void)do_buffer(command, DOBUF_CURRENT, FORWARD, 0, forceit);
@@ -1078,7 +1076,7 @@ char *do_bufdel(int command, char *arg, int addr_count, int start_bnr, int end_b
           break;
         }
         if (!ascii_isdigit(*arg)) {
-          p = skiptowhite_esc(arg);
+          char *p = skiptowhite_esc(arg);
           bnr = buflist_findpat(arg, p, command == DOBUF_WIPE, false, false);
           if (bnr < 0) {                    // failed
             break;
@@ -1125,7 +1123,6 @@ char *do_bufdel(int command, char *arg, int addr_count, int start_bnr, int end_b
 /// Used when it is wiped out and it's the last buffer.
 static int empty_curbuf(int close_others, int forceit, int action)
 {
-  int retval;
   buf_T *buf = curbuf;
 
   if (action == DOBUF_UNLOAD) {
@@ -1158,8 +1155,7 @@ static int empty_curbuf(int close_others, int forceit, int action)
   }
 
   setpcmark();
-  retval = do_ecmd(0, NULL, NULL, NULL, ECMD_ONE,
-                   forceit ? ECMD_FORCEIT : 0, curwin);
+  int retval = do_ecmd(0, NULL, NULL, NULL, ECMD_ONE, forceit ? ECMD_FORCEIT : 0, curwin);
 
   // do_ecmd() may create a new buffer, then we have to delete
   // the old one.  But do_ecmd() may have done that already, check
@@ -2044,12 +2040,11 @@ void free_buf_options(buf_T *buf, int free_p_ff)
 /// Return FAIL for failure, OK for success.
 int buflist_getfile(int n, linenr_T lnum, int options, int forceit)
 {
-  buf_T *buf;
   win_T *wp = NULL;
   fmark_T *fm = NULL;
   colnr_T col;
 
-  buf = buflist_findnr(n);
+  buf_T *buf = buflist_findnr(n);
   if (buf == NULL) {
     if ((options & GETF_ALT) && n == 0) {
       emsg(_(e_noalt));
@@ -2121,9 +2116,7 @@ int buflist_getfile(int n, linenr_T lnum, int options, int forceit)
 /// Go to the last known line number for the current buffer.
 void buflist_getfpos(void)
 {
-  pos_T *fpos;
-
-  fpos = &buflist_findfmark(curbuf)->mark;
+  pos_T *fpos = &buflist_findfmark(curbuf)->mark;
 
   curwin->w_cursor.lnum = fpos->lnum;
   check_cursor_lnum(curwin);
@@ -2143,18 +2136,17 @@ void buflist_getfpos(void)
 /// @return  buffer or NULL if not found
 buf_T *buflist_findname_exp(char *fname)
 {
-  char *ffname;
   buf_T *buf = NULL;
 
   // First make the name into a full path name
-  ffname = FullName_save(fname,
+  char *ffname = FullName_save(fname,
 #ifdef UNIX
-                         // force expansion, get rid of symbolic links
-                         true
+                               // force expansion, get rid of symbolic links
+                               true
 #else
-                         false
+                               false
 #endif
-                         );  // NOLINT(whitespace/parens)
+                               );  // NOLINT(whitespace/parens)
   if (ffname != NULL) {
     buf = buflist_findname(ffname);
     xfree(ffname);
@@ -2204,12 +2196,6 @@ int buflist_findpat(const char *pattern, const char *pattern_end, bool unlisted,
   FUNC_ATTR_NONNULL_ARG(1)
 {
   int match = -1;
-  int find_listed;
-  char *pat;
-  char *patend;
-  int attempt;
-  char *p;
-  int toggledollar;
 
   if (pattern_end == pattern + 1 && (*pattern == '%' || *pattern == '#')) {
     if (*pattern == '%') {
@@ -2230,23 +2216,24 @@ int buflist_findpat(const char *pattern, const char *pattern_end, bool unlisted,
     // Repeat this for finding an unlisted buffer if there was no matching
     // listed buffer.
 
-    pat = file_pat_to_reg_pat(pattern, pattern_end, NULL, false);
+    char *pat = file_pat_to_reg_pat(pattern, pattern_end, NULL, false);
     if (pat == NULL) {
       return -1;
     }
-    patend = pat + strlen(pat) - 1;
-    toggledollar = (patend > pat && *patend == '$');
+    char *patend = pat + strlen(pat) - 1;
+    int toggledollar = (patend > pat && *patend == '$');
 
     // First try finding a listed buffer.  If not found and "unlisted"
     // is true, try finding an unlisted buffer.
-    find_listed = true;
+
+    int find_listed = true;
     while (true) {
-      for (attempt = 0; attempt <= 3; attempt++) {
+      for (int attempt = 0; attempt <= 3; attempt++) {
         // may add '^' and '$'
         if (toggledollar) {
           *patend = (attempt < 2) ? NUL : '$';           // add/remove '$'
         }
-        p = pat;
+        char *p = pat;
         if (*p == '^' && !(attempt & 1)) {               // add/remove '^'
           p++;
         }
@@ -2336,7 +2323,6 @@ int ExpandBufnames(char *pat, int *num_file, char ***file, int options)
   int count = 0;
   int round;
   char *p;
-  int attempt;
   bufmatch_T *matches = NULL;
 
   *num_file = 0;                    // return values in case of FAIL
@@ -2364,7 +2350,7 @@ int ExpandBufnames(char *pat, int *num_file, char ***file, int options)
   fuzmatch_str_T *fuzmatch = NULL;
   // attempt == 0: try match with    '\<', match at start of word
   // attempt == 1: try match without '\<', match anywhere
-  for (attempt = 0; attempt <= (fuzzy ? 0 : 1); attempt++) {
+  for (int attempt = 0; attempt <= (fuzzy ? 0 : 1); attempt++) {
     regmatch_T regmatch;
     if (!fuzzy) {
       if (attempt > 0 && patc == pat) {
@@ -2520,7 +2506,6 @@ static char *buflist_match(regmatch_T *rmp, buf_T *buf, bool ignore_case)
 static char *fname_match(regmatch_T *rmp, char *name, bool ignore_case)
 {
   char *match = NULL;
-  char *p;
 
   // extra check for valid arguments
   if (name == NULL || rmp->regprog == NULL) {
@@ -2533,7 +2518,7 @@ static char *fname_match(regmatch_T *rmp, char *name, bool ignore_case)
     match = name;
   } else if (rmp->regprog != NULL) {
     // Replace $(HOME) with '~' and try matching again.
-    p = home_replace_save(NULL, name);
+    char *p = home_replace_save(NULL, name);
     if (vim_regexec(rmp, p, 0)) {
       match = name;
     }
@@ -3151,10 +3136,8 @@ void fileinfo(int fullname, int shorthelp, int dont_truncate)
   char *name;
   int n;
   char *p;
-  char *buffer;
-  size_t len;
 
-  buffer = xmalloc(IOSIZE);
+  char *buffer = xmalloc(IOSIZE);
 
   if (fullname > 1) {       // 2 CTRL-G: include buffer number
     vim_snprintf(buffer, IOSIZE, "buf %d: ", curbuf->b_fnum);
@@ -3217,7 +3200,7 @@ void fileinfo(int fullname, int shorthelp, int dont_truncate)
                      (int64_t)curbuf->b_ml.ml_line_count,
                      n);
     validate_virtcol();
-    len = strlen(buffer);
+    size_t len = strlen(buffer);
     col_print(buffer + len, IOSIZE - len,
               (int)curwin->w_cursor.col + 1, (int)curwin->w_virtcol + 1);
   }
@@ -3266,7 +3249,6 @@ void maketitle(void)
   char *icon_str = NULL;
   int maxlen = 0;
   int len;
-  int mustset;
   char buf[IOSIZE];
 
   if (!redrawing()) {
@@ -3389,7 +3371,7 @@ void maketitle(void)
 #undef SPACE_FOR_ARGNR
     }
   }
-  mustset = value_change(title_str, &lasttitle);
+  int mustset = value_change(title_str, &lasttitle);
 
   if (p_icon) {
     icon_str = buf;
@@ -3807,12 +3789,10 @@ static int chk_modeline(linenr_T lnum, int flags)
   char *s;
   char *e;
   char *linecopy;                // local copy of any modeline found
-  int prev;
   intmax_t vers;
-  int end;
   int retval = OK;
 
-  prev = -1;
+  int prev = -1;
   for (s = ml_get(lnum); *s != NUL; s++) {
     if (prev == -1 || ascii_isspace(prev)) {
       if ((prev != -1 && strncmp(s, "ex:", (size_t)3) == 0)
@@ -3858,7 +3838,7 @@ static int chk_modeline(linenr_T lnum, int flags)
   // prepare for emsg()
   estack_push(ETYPE_MODELINE, "modelines", lnum);
 
-  end = false;
+  bool end = false;
   while (end == false) {
     s = skipwhite(s);
     if (*s == NUL) {
diff --git a/src/nvim/change.c b/src/nvim/change.c
index bee074385e..46c21da384 100644
--- a/src/nvim/change.c
+++ b/src/nvim/change.c
@@ -1696,14 +1696,13 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
   // concatenate leader and p_extra, if there is a leader
   if (lead_len > 0) {
     if (flags & OPENLINE_COM_LIST && second_line_indent > 0) {
-      int i;
       int padding = second_line_indent
                     - (newindent + (int)strlen(leader));
 
       // Here whitespace is inserted after the comment char.
       // Below, set_indent(newindent, SIN_INSERT) will insert the
       // whitespace needed before the comment char.
-      for (i = 0; i < padding; i++) {
+      for (int i = 0; i < padding; i++) {
         STRCAT(leader, " ");
         less_cols--;
         newcol++;
@@ -1987,9 +1986,7 @@ int get_leader_len(char *line, char **flags, bool backward, bool include_space)
   int got_com = false;
   char part_buf[COM_MAX_LEN];         // buffer for one option part
   char *string;                  // pointer to comment string
-  char *list;
   int middle_match_len = 0;
-  char *prev_list;
   char *saved_flags = NULL;
 
   int result = 0;
@@ -2002,13 +1999,13 @@ int get_leader_len(char *line, char **flags, bool backward, bool include_space)
   while (line[i] != NUL) {
     // scan through the 'comments' option for a match
     int found_one = false;
-    for (list = curbuf->b_p_com; *list;) {
+    for (char *list = curbuf->b_p_com; *list;) {
       // Get one option part into part_buf[].  Advance "list" to next
       // one.  Put "string" at start of string.
       if (!got_com && flags != NULL) {
         *flags = list;              // remember where flags started
       }
-      prev_list = list;
+      char *prev_list = list;
       (void)copy_option_part(&list, part_buf, COM_MAX_LEN, ",");
       string = vim_strchr(part_buf, ':');
       if (string == NULL) {         // missing ':', ignore this part
@@ -2204,7 +2201,6 @@ int get_last_leader_offset(char *line, char **flags)
 
     if (found_one) {
       char part_buf2[COM_MAX_LEN];            // buffer for one option part
-      int len1, len2, off;
 
       result = i;
       // If this comment nests, continue searching.
@@ -2222,7 +2218,7 @@ int get_last_leader_offset(char *line, char **flags)
       while (ascii_iswhite(*com_leader)) {
         com_leader++;
       }
-      len1 = (int)strlen(com_leader);
+      int len1 = (int)strlen(com_leader);
 
       for (list = curbuf->b_p_com; *list;) {
         char *flags_save = list;
@@ -2236,14 +2232,14 @@ int get_last_leader_offset(char *line, char **flags)
         while (ascii_iswhite(*string)) {
           string++;
         }
-        len2 = (int)strlen(string);
+        int len2 = (int)strlen(string);
         if (len2 == 0) {
           continue;
         }
 
         // Now we have to verify whether string ends with a substring
         // beginning the com_leader.
-        for (off = (len2 > i ? i : len2); off > 0 && off + len1 > len2;) {
+        for (int off = (len2 > i ? i : len2); off > 0 && off + len1 > len2;) {
           off--;
           if (!strncmp(string + off, com_leader, (size_t)(len2 - off))) {
             if (i - off < lower_check_bound) {
diff --git a/src/nvim/charset.c b/src/nvim/charset.c
index 2edf9a87cc..0adcc09ec7 100644
--- a/src/nvim/charset.c
+++ b/src/nvim/charset.c
@@ -88,10 +88,6 @@ int init_chartab(void)
 int buf_init_chartab(buf_T *buf, int global)
 {
   int c;
-  int c2;
-  int i;
-  bool tilde;
-  bool do_isalpha;
 
   if (global) {
     // Set the default size for printable characters:
@@ -130,7 +126,7 @@ int buf_init_chartab(buf_T *buf, int global)
   // Walk through the 'isident', 'iskeyword', 'isfname' and 'isprint'
   // options Each option is a list of characters, character numbers or
   // ranges, separated by commas, e.g.: "200-210,x,#-178,-"
-  for (i = global ? 0 : 3; i <= 3; i++) {
+  for (int i = global ? 0 : 3; i <= 3; i++) {
     const char *p;
     if (i == 0) {
       // first round: 'isident'
@@ -147,8 +143,8 @@ int buf_init_chartab(buf_T *buf, int global)
     }
 
     while (*p) {
-      tilde = false;
-      do_isalpha = false;
+      bool tilde = false;
+      bool do_isalpha = false;
 
       if ((*p == '^') && (p[1] != NUL)) {
         tilde = true;
@@ -160,7 +156,7 @@ int buf_init_chartab(buf_T *buf, int global)
       } else {
         c = mb_ptr2char_adv(&p);
       }
-      c2 = -1;
+      int c2 = -1;
 
       if ((*p == '-') && (p[1] != NUL)) {
         p++;
@@ -431,7 +427,6 @@ char *str_foldcase(char *str, int orglen, char *buf, int buflen)
   FUNC_ATTR_NONNULL_RET
 {
   garray_T ga;
-  int i;
   int len = orglen;
 
 #define GA_CHAR(i) ((char *)ga.ga_data)[i]
@@ -461,7 +456,7 @@ char *str_foldcase(char *str, int orglen, char *buf, int buflen)
   }
 
   // Make each character lower case.
-  i = 0;
+  int i = 0;
   while (STR_CHAR(i) != NUL) {
     int c = utf_ptr2char(STR_PTR(i));
     int olen = utf_ptr2len(STR_PTR(i));
diff --git a/src/nvim/cmdexpand.c b/src/nvim/cmdexpand.c
index 6a6cf9e4af..cba06976c9 100644
--- a/src/nvim/cmdexpand.c
+++ b/src/nvim/cmdexpand.c
@@ -225,7 +225,6 @@ static void ExpandEscape(expand_T *xp, char *str, int numfiles, char **files, in
 int nextwild(expand_T *xp, int type, int options, bool escape)
 {
   CmdlineInfo *const ccline = get_cmdline_info();
-  int i;
   char *p2;
 
   if (xp->xp_numfiles == -1) {
@@ -249,7 +248,7 @@ int nextwild(expand_T *xp, int type, int options, bool escape)
     ui_flush();
   }
 
-  i = (int)(xp->xp_pattern - ccline->cmdbuff);
+  int i = (int)(xp->xp_pattern - ccline->cmdbuff);
   assert(ccline->cmdpos >= i);
   xp->xp_pattern_len = (size_t)ccline->cmdpos - (size_t)i;
 
@@ -444,11 +443,8 @@ static int wildmenu_match_len(expand_T *xp, char *s)
 /// @param matches  list of matches
 static void redraw_wildmenu(expand_T *xp, int num_matches, char **matches, int match, int showtail)
 {
-  int row;
-  char *buf;
   int len;
   int clen;                     // length in screen cells
-  int fillchar;
   int attr;
   int i;
   bool highlight = true;
@@ -463,7 +459,7 @@ static void redraw_wildmenu(expand_T *xp, int num_matches, char **matches, int m
     return;
   }
 
-  buf = xmalloc((size_t)Columns * MB_MAXBYTES + 1);
+  char *buf = xmalloc((size_t)Columns * MB_MAXBYTES + 1);
 
   if (match == -1) {    // don't show match but original text
     match = 0;
@@ -511,7 +507,7 @@ static void redraw_wildmenu(expand_T *xp, int num_matches, char **matches, int m
     }
   }
 
-  fillchar = fillchar_status(&attr, curwin);
+  int fillchar = fillchar_status(&attr, curwin);
 
   if (first_match == 0) {
     *buf = NUL;
@@ -570,7 +566,7 @@ static void redraw_wildmenu(expand_T *xp, int num_matches, char **matches, int m
 
   buf[len] = NUL;
 
-  row = cmdline_row - 1;
+  int row = cmdline_row - 1;
   if (row >= 0) {
     if (wild_menu_showing == 0 || wild_menu_showing == WM_LIST) {
       if (msg_scrolled > 0) {
@@ -1032,7 +1028,7 @@ int showmatches(expand_T *xp, int wildmenu)
   CmdlineInfo *const ccline = get_cmdline_info();
   int numMatches;
   char **matches;
-  int i, j;
+  int j;
   int maxlen;
   int lines;
   int columns;
@@ -1041,8 +1037,8 @@ int showmatches(expand_T *xp, int wildmenu)
 
   if (xp->xp_numfiles == -1) {
     set_expand_context(xp);
-    i = expand_cmdline(xp, ccline->cmdbuff, ccline->cmdpos,
-                       &numMatches, &matches);
+    int i = expand_cmdline(xp, ccline->cmdbuff, ccline->cmdpos,
+                           &numMatches, &matches);
     showtail = expand_showtail(xp);
     if (i != EXPAND_OK) {
       return i;
@@ -1080,7 +1076,7 @@ int showmatches(expand_T *xp, int wildmenu)
   } else {
     // find the length of the longest file name
     maxlen = 0;
-    for (i = 0; i < numMatches; i++) {
+    for (int i = 0; i < numMatches; i++) {
       if (!showtail && (xp->xp_context == EXPAND_FILES
                         || xp->xp_context == EXPAND_SHELLCMD
                         || xp->xp_context == EXPAND_BUFFERS)) {
@@ -1116,7 +1112,7 @@ int showmatches(expand_T *xp, int wildmenu)
     }
 
     // list the files line by line
-    for (i = 0; i < lines; i++) {
+    for (int i = 0; i < lines; i++) {
       showmatches_oneline(xp, matches, numMatches, lines, i, maxlen, showtail, attr);
       if (got_int) {
         got_int = false;
@@ -1140,11 +1136,10 @@ int showmatches(expand_T *xp, int wildmenu)
 /// Return the tail of file name path "s", ignoring a trailing "/".
 static char *showmatches_gettail(char *s, bool eager)
 {
-  char *p;
   char *t = s;
   bool had_sep = false;
 
-  for (p = s; *p != NUL;) {
+  for (char *p = s; *p != NUL;) {
     if (vim_ispathsep(*p)
 #ifdef BACKSLASH_IN_FILENAME
         && !rem_backslash(p)
@@ -1169,9 +1164,6 @@ static char *showmatches_gettail(char *s, bool eager)
 /// returned.
 static bool expand_showtail(expand_T *xp)
 {
-  char *s;
-  char *end;
-
   // When not completing file names a "/" may mean something different.
   if (xp->xp_context != EXPAND_FILES
       && xp->xp_context != EXPAND_SHELLCMD
@@ -1179,12 +1171,12 @@ static bool expand_showtail(expand_T *xp)
     return false;
   }
 
-  end = path_tail(xp->xp_pattern);
+  char *end = path_tail(xp->xp_pattern);
   if (end == xp->xp_pattern) {          // there is no path separator
     return false;
   }
 
-  for (s = xp->xp_pattern; s < end; s++) {
+  for (char *s = xp->xp_pattern; s < end; s++) {
     // Skip escaped wildcards.  Only when the backslash is not a path
     // separator, on DOS the '*' "path\*\file" must not be skipped.
     if (rem_backslash(s)) {
@@ -1209,9 +1201,6 @@ char *addstar(char *fname, size_t len, int context)
 {
   char *retval;
   size_t i, j;
-  size_t new_len;
-  char *tail;
-  int ends_in_star;
 
   if (context != EXPAND_FILES
       && context != EXPAND_FILES_IN_PATH
@@ -1236,7 +1225,7 @@ char *addstar(char *fname, size_t len, int context)
         || context == EXPAND_LUA) {
       retval = xstrnsave(fname, len);
     } else {
-      new_len = len + 2;                // +2 for '^' at start, NUL at end
+      size_t new_len = len + 2;                // +2 for '^' at start, NUL at end
       for (i = 0; i < len; i++) {
         if (fname[i] == '*' || fname[i] == '~') {
           new_len++;                    // '*' needs to be replaced by ".*"
@@ -1304,8 +1293,8 @@ char *addstar(char *fname, size_t len, int context)
     // $ could be anywhere in the tail.
     // ` could be anywhere in the file name.
     // When the name ends in '$' don't add a star, remove the '$'.
-    tail = path_tail(retval);
-    ends_in_star = (len > 0 && retval[len - 1] == '*');
+    char *tail = path_tail(retval);
+    int ends_in_star = (len > 0 && retval[len - 1] == '*');
 #ifndef BACKSLASH_IN_FILENAME
     for (ssize_t k = (ssize_t)len - 2; k >= 0; k--) {
       if (retval[k] != '\\') {
@@ -2981,18 +2970,16 @@ static void expand_shellcmd_onedir(char *buf, char *s, size_t l, char *pat, char
 static void expand_shellcmd(char *filepat, char ***matches, int *numMatches, int flagsarg)
   FUNC_ATTR_NONNULL_ALL
 {
-  char *pat;
-  int i;
   char *path = NULL;
   garray_T ga;
   char *buf = xmalloc(MAXPATHL);
-  char *s, *e;
+  char *e;
   int flags = flagsarg;
   bool did_curdir = false;
 
   // for ":set path=" and ":set tags=" halve backslashes for escaped space
-  pat = xstrdup(filepat);
-  for (i = 0; pat[i]; i++) {
+  char *pat = xstrdup(filepat);
+  for (int i = 0; pat[i]; i++) {
     if (pat[i] == '\\' && pat[i + 1] == ' ') {
       STRMOVE(pat + i, pat + i + 1);
     }
@@ -3022,7 +3009,7 @@ static void expand_shellcmd(char *filepat, char ***matches, int *numMatches, int
   ga_init(&ga, (int)sizeof(char *), 10);
   hashtab_T found_ht;
   hash_init(&found_ht);
-  for (s = path;; s = e) {
+  for (char *s = path;; s = e) {
     e = vim_strchr(s, ENV_SEPCHAR);
     if (e == NULL) {
       e = s + strlen(s);
@@ -3071,7 +3058,6 @@ static void *call_user_expand_func(user_expand_func_T user_expand_func, expand_T
   CmdlineInfo *const ccline = get_cmdline_info();
   char keep = 0;
   typval_T args[4];
-  char *pat = NULL;
   const sctx_T save_current_sctx = current_sctx;
 
   if (xp->xp_arg == NULL || xp->xp_arg[0] == '\0' || xp->xp_line == NULL) {
@@ -3083,7 +3069,7 @@ static void *call_user_expand_func(user_expand_func_T user_expand_func, expand_T
     ccline->cmdbuff[ccline->cmdlen] = 0;
   }
 
-  pat = xstrnsave(xp->xp_pattern, xp->xp_pattern_len);
+  char *pat = xstrnsave(xp->xp_pattern, xp->xp_pattern_len);
   args[0].v_type = VAR_STRING;
   args[1].v_type = VAR_STRING;
   args[2].v_type = VAR_NUMBER;
diff --git a/src/nvim/cmdhist.c b/src/nvim/cmdhist.c
index 25093a2b1c..e2916d1641 100644
--- a/src/nvim/cmdhist.c
+++ b/src/nvim/cmdhist.c
@@ -519,14 +519,12 @@ static int del_history_idx(int histype, int idx)
 /// "histadd()" function
 void f_histadd(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
-  HistoryType histype;
-
   rettv->vval.v_number = false;
   if (check_secure()) {
     return;
   }
   const char *str = tv_get_string_chk(&argvars[0]);  // NULL on type error
-  histype = str != NULL ? get_histtype(str, strlen(str), false) : HIST_INVALID;
+  HistoryType histype = str != NULL ? get_histtype(str, strlen(str), false) : HIST_INVALID;
   if (histype == HIST_INVALID) {
     return;
   }
@@ -605,7 +603,6 @@ void ex_history(exarg_T *eap)
   int histype2 = HIST_CMD;
   int hisidx1 = 1;
   int hisidx2 = -1;
-  int i;
   char *end;
   char *arg = eap->arg;
 
@@ -661,7 +658,7 @@ void ex_history(exarg_T *eap)
       k = (-k > hislen) ? 0 : hist[(hislen + k + idx + 1) % hislen].hisnum;
     }
     if (idx >= 0 && j <= k) {
-      for (i = idx + 1; !got_int; i++) {
+      for (int i = idx + 1; !got_int; i++) {
         if (i == hislen) {
           i = 0;
         }
diff --git a/src/nvim/cursor_shape.c b/src/nvim/cursor_shape.c
index 37fa0ccd8e..2e5a28b07b 100644
--- a/src/nvim/cursor_shape.c
+++ b/src/nvim/cursor_shape.c
@@ -112,10 +112,9 @@ const char *parse_shape_opt(int what)
   int len;
   int i;
   int found_ve = false;                 // found "ve" flag
-  int round;
 
   // First round: check for errors; second round: do it for real.
-  for (round = 1; round <= 2; round++) {
+  for (int round = 1; round <= 2; round++) {
     if (round == 2 || *p_guicursor == NUL) {
       // Set all entries to default (block, blinkon0, default color).
       // This is the default for anything that is not set.
diff --git a/src/nvim/debugger.c b/src/nvim/debugger.c
index bfb15d59f5..9ab95eaec6 100644
--- a/src/nvim/debugger.c
+++ b/src/nvim/debugger.c
@@ -505,7 +505,6 @@ static typval_T *eval_expr_no_emsg(struct debuggy *const bp)
 static int dbg_parsearg(char *arg, garray_T *gap)
 {
   char *p = arg;
-  char *q;
   bool here = false;
 
   ga_grow(gap, 1);
@@ -561,7 +560,7 @@ static int dbg_parsearg(char *arg, garray_T *gap)
     // Expand the file name in the same way as do_source().  This means
     // doing it twice, so that $DIR/file gets expanded when $DIR is
     // "~/dir".
-    q = expand_env_save(p);
+    char *q = expand_env_save(p);
     if (q == NULL) {
       return FAIL;
     }
diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index aee0081e86..9c75a21b2c 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -340,8 +340,7 @@ static void diff_mark_adjust_tp(tabpage_T *tp, int idx, linenr_T line1, linenr_T
 
       dnext->df_lnum[idx] = line1;
       dnext->df_count[idx] = inserted;
-      int i;
-      for (i = 0; i < DB_COUNT; i++) {
+      for (int i = 0; i < DB_COUNT; i++) {
         if ((tp->tp_diffbuf[i] != NULL) && (i != idx)) {
           if (dprev == NULL) {
             dnext->df_lnum[i] = line1;
@@ -472,8 +471,7 @@ static void diff_mark_adjust_tp(tabpage_T *tp, int idx, linenr_T line1, linenr_T
     // check if this block touches the previous one, may merge them.
     if ((dprev != NULL) && !dp->is_linematched
         && (dprev->df_lnum[idx] + dprev->df_count[idx] == dp->df_lnum[idx])) {
-      int i;
-      for (i = 0; i < DB_COUNT; i++) {
+      for (int i = 0; i < DB_COUNT; i++) {
         if (tp->tp_diffbuf[i] != NULL) {
           dprev->df_count[i] += dp->df_count[i];
         }
diff --git a/src/nvim/digraph.c b/src/nvim/digraph.c
index b29b5aed72..bc0ce99c5e 100644
--- a/src/nvim/digraph.c
+++ b/src/nvim/digraph.c
@@ -2074,8 +2074,6 @@ char *keymap_init(void)
 /// @param eap
 void ex_loadkeymap(exarg_T *eap)
 {
-  char *s;
-
 #define KMAP_LLEN 200  // max length of "to" and "from" together
   char buf[KMAP_LLEN + 11];
   char *save_cpo = p_cpo;
@@ -2106,7 +2104,7 @@ void ex_loadkeymap(exarg_T *eap)
 
     if ((*p != '"') && (*p != NUL)) {
       kmap_T *kp = GA_APPEND_VIA_PTR(kmap_T, &curbuf->b_kmap_ga);
-      s = skiptowhite(p);
+      char *s = skiptowhite(p);
       kp->from = xmemdupz(p, (size_t)(s - p));
       p = skipwhite(s);
       s = skiptowhite(p);
diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 5f61848188..11b4e55c5c 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -401,8 +401,6 @@ static void handle_foldcolumn(win_T *wp, winlinevars_T *wlv)
 size_t fill_foldcolumn(char *p, win_T *wp, foldinfo_T foldinfo, linenr_T lnum, int *n_closing)
 {
   int i = 0;
-  int level;
-  int first_level;
   int fdc = compute_foldcolumn(wp, 0);    // available cell width
   size_t char_counter = 0;
   int symbol = 0;
@@ -411,11 +409,11 @@ size_t fill_foldcolumn(char *p, win_T *wp, foldinfo_T foldinfo, linenr_T lnum, i
   // Init to all spaces.
   memset(p, ' ', MB_MAXCHAR * (size_t)fdc + 1);
 
-  level = foldinfo.fi_level;
+  int level = foldinfo.fi_level;
 
   // If the column is too narrow, we start at the lowest level that
   // fits and use numbers to indicate the depth.
-  first_level = level - fdc - closed + 1;
+  int first_level = level - fdc - closed + 1;
   if (first_level < 1) {
     first_level = 1;
   }
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index 42b714ef47..ce547b55fe 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -1387,7 +1387,6 @@ void ins_redraw(bool ready)
 // Handle a CTRL-V or CTRL-Q typed in Insert mode.
 static void ins_ctrl_v(void)
 {
-  int c;
   bool did_putchar = false;
 
   // may need to redraw when no more chars available now
@@ -1402,7 +1401,7 @@ static void ins_ctrl_v(void)
   add_to_showcmd_c(Ctrl_V);
 
   // Do not include modifiers into the key for CTRL-SHIFT-V.
-  c = get_literal(mod_mask & MOD_MASK_SHIFT);
+  int c = get_literal(mod_mask & MOD_MASK_SHIFT);
   if (did_putchar) {
     // when the line fits in 'columns' the '^' is at the start of the next
     // line and will not removed by the redraw
@@ -1491,10 +1490,9 @@ char *prompt_text(void)
 static void init_prompt(int cmdchar_todo)
 {
   char *prompt = prompt_text();
-  char *text;
 
   curwin->w_cursor.lnum = curbuf->b_ml.ml_line_count;
-  text = get_cursor_line_ptr();
+  char *text = get_cursor_line_ptr();
   if (strncmp(text, prompt, strlen(prompt)) != 0) {
     // prompt is missing, insert it or append a line with it
     if (*text == NUL) {
@@ -1558,13 +1556,12 @@ void edit_unputchar(void)
 void display_dollar(colnr_T col_arg)
 {
   colnr_T col = col_arg < 0 ? 0 : col_arg;
-  colnr_T save_col;
 
   if (!redrawing()) {
     return;
   }
 
-  save_col = curwin->w_cursor.col;
+  colnr_T save_col = curwin->w_cursor.col;
   curwin->w_cursor.col = col;
 
   // If on the last byte of a multi-byte move to the first byte.
@@ -1599,14 +1596,7 @@ void undisplay_dollar(void)
 /// @param call_changed_bytes  call changed_bytes()
 void change_indent(int type, int amount, int round, int replaced, int call_changed_bytes)
 {
-  int vcol;
-  int last_vcol;
   int insstart_less;                    // reduction for Insstart.col
-  int new_cursor_col;
-  char *ptr;
-  int save_p_list;
-  int start_col;
-  colnr_T vc;
   colnr_T orig_col = 0;                 // init for GCC
   char *orig_line = NULL;     // init for GCC
 
@@ -1617,18 +1607,18 @@ void change_indent(int type, int amount, int round, int replaced, int call_chang
   }
 
   // for the following tricks we don't want list mode
-  save_p_list = curwin->w_p_list;
+  int save_p_list = curwin->w_p_list;
   curwin->w_p_list = false;
-  vc = getvcol_nolist(&curwin->w_cursor);
-  vcol = vc;
+  colnr_T vc = getvcol_nolist(&curwin->w_cursor);
+  int vcol = vc;
 
   // For Replace mode we need to fix the replace stack later, which is only
   // possible when the cursor is in the indent.  Remember the number of
   // characters before the cursor if it's possible.
-  start_col = curwin->w_cursor.col;
+  int start_col = curwin->w_cursor.col;
 
   // determine offset from first non-blank
-  new_cursor_col = curwin->w_cursor.col;
+  int new_cursor_col = curwin->w_cursor.col;
   beginline(BL_WHITE);
   new_cursor_col -= curwin->w_cursor.col;
 
@@ -1681,8 +1671,8 @@ void change_indent(int type, int amount, int round, int replaced, int call_chang
     curwin->w_virtcol = (colnr_T)((vcol < 0) ? 0 : vcol);
 
     // Advance the cursor until we reach the right screen column.
-    last_vcol = 0;
-    ptr = get_cursor_line_ptr();
+    int last_vcol = 0;
+    char *ptr = get_cursor_line_ptr();
     chartabsize_T cts;
     init_chartabsize_arg(&cts, curwin, 0, 0, ptr, ptr);
     while (cts.cts_vcol <= (int)curwin->w_virtcol) {
@@ -1872,9 +1862,7 @@ static bool del_char_after_col(int limit_col)
 /// @param  no_simplify  do not include modifiers into the key
 int get_literal(bool no_simplify)
 {
-  int cc;
   int nc;
-  int i;
   bool hex = false;
   bool octal = false;
   int unicode = 0;
@@ -1884,8 +1872,8 @@ int get_literal(bool no_simplify)
   }
 
   no_mapping++;                 // don't map the next key hits
-  cc = 0;
-  i = 0;
+  int cc = 0;
+  int i = 0;
   while (true) {
     nc = plain_vgetc();
     if (!no_simplify) {
@@ -2313,15 +2301,13 @@ int stop_arrow(void)
 /// @param nomove  <c-\><c-o>, don't move cursor
 static void stop_insert(pos_T *end_insert_pos, int esc, int nomove)
 {
-  char *ptr;
-
   stop_redo_ins();
   replace_flush();              // abandon replace stack
 
   // Save the inserted text for later redo with ^@ and CTRL-A.
   // Don't do it when "restart_edit" was set and nothing was inserted,
   // otherwise CTRL-O w and then <Left> will clear "last_insert".
-  ptr = get_inserted();
+  char *ptr = get_inserted();
   int added = ptr == NULL ? 0 : (int)strlen(ptr) - new_insert_skip;
   if (did_restart_edit == 0 || added > 0) {
     xfree(last_insert);
@@ -2432,11 +2418,9 @@ static void stop_insert(pos_T *end_insert_pos, int esc, int nomove)
 // Used for the replace command.
 void set_last_insert(int c)
 {
-  char *s;
-
   xfree(last_insert);
   last_insert = xmalloc(MB_MAXBYTES * 3 + 5);
-  s = last_insert;
+  char *s = last_insert;
   // Use the CTRL-V only when entering a special char
   if (c < ' ' || c == DEL) {
     *s++ = Ctrl_V;
@@ -2489,7 +2473,6 @@ void beginline(int flags)
 int oneright(void)
 {
   char *ptr;
-  int l;
 
   if (virtual_active()) {
     pos_T prevpos = curwin->w_cursor;
@@ -2509,7 +2492,7 @@ int oneright(void)
     return FAIL;            // already at the very end
   }
 
-  l = utfc_ptr2len(ptr);
+  int l = utfc_ptr2len(ptr);
 
   // move "l" bytes right, but don't end up on the NUL, unless 'virtualedit'
   // contains "onemore".
@@ -2526,7 +2509,6 @@ int oneright(void)
 int oneleft(void)
 {
   if (virtual_active()) {
-    int width;
     int v = getviscol();
 
     if (v == 0) {
@@ -2534,7 +2516,7 @@ int oneleft(void)
     }
 
     // We might get stuck on 'showbreak', skip over it.
-    width = 1;
+    int width = 1;
     while (true) {
       coladvance(v - width);
       // getviscol() is slow, skip it when 'showbreak' is empty,
@@ -2692,11 +2674,9 @@ int cursor_down(int n, int upd_topline)
 int stuff_inserted(int c, int count, int no_esc)
 {
   char *esc_ptr;
-  char *ptr;
-  char *last_ptr;
   char last = NUL;
 
-  ptr = get_last_insert();
+  char *ptr = get_last_insert();
   if (ptr == NULL) {
     emsg(_(e_noinstext));
     return FAIL;
@@ -2714,7 +2694,7 @@ int stuff_inserted(int c, int count, int no_esc)
   // when the last char is either "0" or "^" it will be quoted if no ESC
   // comes after it OR if it will inserted more than once and "ptr"
   // starts with ^D.  -- Acevedo
-  last_ptr = (esc_ptr ? esc_ptr : ptr + strlen(ptr)) - 1;
+  char *last_ptr = (esc_ptr ? esc_ptr : ptr + strlen(ptr)) - 1;
   if (last_ptr >= ptr && (*last_ptr == '0' || *last_ptr == '^')
       && (no_esc || (*ptr == Ctrl_D && count > 1))) {
     last = *last_ptr;
@@ -2758,14 +2738,11 @@ char *get_last_insert(void)
 // Returns pointer to allocated memory (must be freed) or NULL.
 char *get_last_insert_save(void)
 {
-  char *s;
-  int len;
-
   if (last_insert == NULL) {
     return NULL;
   }
-  s = xstrdup(last_insert + last_insert_skip);
-  len = (int)strlen(s);
+  char *s = xstrdup(last_insert + last_insert_skip);
+  int len = (int)strlen(s);
   if (len > 0 && s[len - 1] == ESC) {         // remove trailing ESC
     s[len - 1] = NUL;
   }
@@ -2843,9 +2820,8 @@ void replace_push(int c)
 int replace_push_mb(char *p)
 {
   int l = utfc_ptr2len(p);
-  int j;
 
-  for (j = l - 1; j >= 0; j--) {
+  for (int j = l - 1; j >= 0; j--) {
     replace_push(p[j]);
   }
   return l;
@@ -2896,11 +2872,10 @@ static void mb_replace_pop_ins(int cc)
 {
   int n;
   uint8_t buf[MB_MAXBYTES + 1];
-  int i;
 
   if ((n = MB_BYTE2LEN(cc)) > 1) {
     buf[0] = (uint8_t)cc;
-    for (i = 1; i < n; i++) {
+    for (int i = 1; i < n; i++) {
       buf[i] = (uint8_t)replace_pop();
     }
     ins_bytes_len((char *)buf, (size_t)n);
@@ -2922,14 +2897,14 @@ static void mb_replace_pop_ins(int cc)
 
     buf[0] = (uint8_t)c;
     assert(n > 1);
-    for (i = 1; i < n; i++) {
+    for (int i = 1; i < n; i++) {
       buf[i] = (uint8_t)replace_pop();
     }
     if (utf_iscomposing(utf_ptr2char((char *)buf))) {
       ins_bytes_len((char *)buf, (size_t)n);
     } else {
       // Not a composing char, put it back.
-      for (i = n - 1; i >= 0; i--) {
+      for (int i = n - 1; i >= 0; i--) {
         replace_push(buf[i]);
       }
       break;
@@ -2955,11 +2930,10 @@ static void replace_flush(void)
 // using composing characters, use del_char_after_col() instead of del_char().
 static void replace_do_bs(int limit_col)
 {
-  int cc;
   colnr_T start_vcol;
   const int l_State = State;
 
-  cc = replace_pop();
+  int cc = replace_pop();
   if (cc > 0) {
     int orig_len = 0;
     int orig_vcols = 0;
@@ -3235,7 +3209,6 @@ bool in_cinkeys(int keytyped, int when, bool line_is_empty)
 static void ins_reg(void)
 {
   bool need_redraw = false;
-  int regname;
   int literally = 0;
   int vis_active = VIsual_active;
 
@@ -3253,7 +3226,7 @@ static void ins_reg(void)
   // deleted when ESC is hit.
   no_mapping++;
   allow_keys++;
-  regname = plain_vgetc();
+  int regname = plain_vgetc();
   LANGMAP_ADJUST(regname, true);
   if (regname == Ctrl_R || regname == Ctrl_O || regname == Ctrl_P) {
     // Get a third key for literal register insertion
@@ -3324,8 +3297,6 @@ static void ins_reg(void)
 // CTRL-G commands in Insert mode.
 static void ins_ctrl_g(void)
 {
-  int c;
-
   // Right after CTRL-X the cursor will be after the ruler.
   setcursor();
 
@@ -3333,7 +3304,7 @@ static void ins_ctrl_g(void)
   // deleted when ESC is hit.
   no_mapping++;
   allow_keys++;
-  c = plain_vgetc();
+  int c = plain_vgetc();
   no_mapping--;
   allow_keys--;
   switch (c) {
@@ -3709,9 +3680,7 @@ static bool ins_bs(int c, int mode, int *inserted_space_p)
 {
   int cc;
   int temp = 0;                     // init for GCC
-  colnr_T save_col;
   bool did_backspace = false;
-  int in_indent;
   int cpc[MAX_MCO];                 // composing characters
   bool call_fix_indent = false;
 
@@ -3736,7 +3705,7 @@ static bool ins_bs(int c, int mode, int *inserted_space_p)
   if (stop_arrow() == FAIL) {
     return false;
   }
-  in_indent = inindent(0);
+  int in_indent = inindent(0);
   if (in_indent) {
     can_cindent = false;
   }
@@ -3822,7 +3791,7 @@ static bool ins_bs(int c, int mode, int *inserted_space_p)
         State = MODE_NORMAL;
         // restore characters (blanks) deleted after cursor
         while (cc > 0) {
-          save_col = curwin->w_cursor.col;
+          colnr_T save_col = curwin->w_cursor.col;
           mb_replace_pop_ins(cc);
           curwin->w_cursor.col = save_col;
           cc = replace_pop();
@@ -3843,7 +3812,7 @@ static bool ins_bs(int c, int mode, int *inserted_space_p)
     if (mode == BACKSPACE_LINE
         && (curbuf->b_p_ai || cindent_on())
         && !revins_on) {
-      save_col = curwin->w_cursor.col;
+      colnr_T save_col = curwin->w_cursor.col;
       beginline(BL_WHITE);
       if (curwin->w_cursor.col < save_col) {
         mincol = curwin->w_cursor.col;
@@ -3864,14 +3833,13 @@ static bool ins_bs(int c, int mode, int *inserted_space_p)
                         && (!*inserted_space_p || arrow_used)))))) {
       colnr_T vcol;
       colnr_T want_vcol;
-      colnr_T start_vcol;
 
       *inserted_space_p = false;
       // Compute the virtual column where we want to be.  Since
       // 'showbreak' may get in the way, need to get the last column of
       // the previous character.
       getvcol(curwin, &curwin->w_cursor, &vcol, NULL, NULL);
-      start_vcol = vcol;
+      colnr_T start_vcol = vcol;
       dec_cursor();
       getvcol(curwin, &curwin->w_cursor, NULL, NULL, &want_vcol);
       inc_cursor();
@@ -4017,14 +3985,13 @@ static bool ins_bs(int c, int mode, int *inserted_space_p)
 
 static void ins_left(void)
 {
-  pos_T tpos;
   const bool end_change = dont_sync_undo == kFalse;  // end undoable change
 
   if ((fdo_flags & FDO_HOR) && KeyTyped) {
     foldOpenCursor();
   }
   undisplay_dollar();
-  tpos = curwin->w_cursor;
+  pos_T tpos = curwin->w_cursor;
   if (oneleft() == OK) {
     start_arrow_with_change(&tpos, end_change);
     if (!end_change) {
@@ -4050,13 +4017,11 @@ static void ins_left(void)
 
 static void ins_home(int c)
 {
-  pos_T tpos;
-
   if ((fdo_flags & FDO_HOR) && KeyTyped) {
     foldOpenCursor();
   }
   undisplay_dollar();
-  tpos = curwin->w_cursor;
+  pos_T tpos = curwin->w_cursor;
   if (c == K_C_HOME) {
     curwin->w_cursor.lnum = 1;
   }
@@ -4068,13 +4033,11 @@ static void ins_home(int c)
 
 static void ins_end(int c)
 {
-  pos_T tpos;
-
   if ((fdo_flags & FDO_HOR) && KeyTyped) {
     foldOpenCursor();
   }
   undisplay_dollar();
-  tpos = curwin->w_cursor;
+  pos_T tpos = curwin->w_cursor;
   if (c == K_C_END) {
     curwin->w_cursor.lnum = curbuf->b_ml.ml_line_count;
   }
@@ -4166,12 +4129,11 @@ static void ins_s_right(void)
 /// @param startcol  when true move to Insstart.col
 static void ins_up(bool startcol)
 {
-  pos_T tpos;
   linenr_T old_topline = curwin->w_topline;
   int old_topfill = curwin->w_topfill;
 
   undisplay_dollar();
-  tpos = curwin->w_cursor;
+  pos_T tpos = curwin->w_cursor;
   if (cursor_up(1, true) == OK) {
     if (startcol) {
       coladvance(getvcol_nolist(&Insstart));
@@ -4189,8 +4151,6 @@ static void ins_up(bool startcol)
 
 static void ins_pageup(void)
 {
-  pos_T tpos;
-
   undisplay_dollar();
 
   if (mod_mask & MOD_MASK_CTRL) {
@@ -4202,7 +4162,7 @@ static void ins_pageup(void)
     return;
   }
 
-  tpos = curwin->w_cursor;
+  pos_T tpos = curwin->w_cursor;
   if (onepage(BACKWARD, 1) == OK) {
     start_arrow(&tpos);
     can_cindent = true;
@@ -4214,12 +4174,11 @@ static void ins_pageup(void)
 /// @param startcol  when true move to Insstart.col
 static void ins_down(bool startcol)
 {
-  pos_T tpos;
   linenr_T old_topline = curwin->w_topline;
   int old_topfill = curwin->w_topfill;
 
   undisplay_dollar();
-  tpos = curwin->w_cursor;
+  pos_T tpos = curwin->w_cursor;
   if (cursor_down(1, true) == OK) {
     if (startcol) {
       coladvance(getvcol_nolist(&Insstart));
@@ -4237,8 +4196,6 @@ static void ins_down(bool startcol)
 
 static void ins_pagedown(void)
 {
-  pos_T tpos;
-
   undisplay_dollar();
 
   if (mod_mask & MOD_MASK_CTRL) {
@@ -4250,7 +4207,7 @@ static void ins_pagedown(void)
     return;
   }
 
-  tpos = curwin->w_cursor;
+  pos_T tpos = curwin->w_cursor;
   if (onepage(FORWARD, 1) == OK) {
     start_arrow(&tpos);
     can_cindent = true;
@@ -4528,7 +4485,6 @@ bool ins_eol(int c)
 // done.
 static int ins_digraph(void)
 {
-  int c;
   bool did_putchar = false;
 
   pc_status = PC_STATUS_UNSET;
@@ -4545,7 +4501,7 @@ static int ins_digraph(void)
   // mode message to be deleted when ESC is hit
   no_mapping++;
   allow_keys++;
-  c = plain_vgetc();
+  int c = plain_vgetc();
   no_mapping--;
   allow_keys--;
   if (did_putchar) {
@@ -4597,9 +4553,7 @@ static int ins_digraph(void)
 // Returns the char to be inserted, or NUL if none found.
 int ins_copychar(linenr_T lnum)
 {
-  int c;
-  char *ptr, *prev_ptr;
-  char *line;
+  char *ptr;
 
   if (lnum < 1 || lnum > curbuf->b_ml.ml_line_count) {
     vim_beep(BO_COPY);
@@ -4608,8 +4562,8 @@ int ins_copychar(linenr_T lnum)
 
   // try to advance to the cursor column
   validate_virtcol();
-  line = ml_get(lnum);
-  prev_ptr = line;
+  char *line = ml_get(lnum);
+  char *prev_ptr = line;
 
   chartabsize_T cts;
   init_chartabsize_arg(&cts, curwin, lnum, 0, line, line);
@@ -4625,7 +4579,7 @@ int ins_copychar(linenr_T lnum)
   }
   clear_chartabsize_arg(&cts);
 
-  c = utf_ptr2char(ptr);
+  int c = utf_ptr2char(ptr);
   if (c == NUL) {
     vim_beep(BO_COPY);
   }
@@ -4811,9 +4765,8 @@ void set_can_cindent(bool val)
 int ins_apply_autocmds(event_T event)
 {
   varnumber_T tick = buf_get_changedtick(curbuf);
-  int r;
 
-  r = apply_autocmds(event, NULL, NULL, false, curbuf);
+  int r = apply_autocmds(event, NULL, NULL, false, curbuf);
 
   // If u_savesub() was called then we are not prepared to start
   // a new line.  Call u_save() with no contents to fix that.
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index be9d0abc42..6d2c276df4 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -1867,14 +1867,13 @@ notify:
 void *eval_for_line(const char *arg, bool *errp, exarg_T *eap, evalarg_T *const evalarg)
 {
   forinfo_T *fi = xcalloc(1, sizeof(forinfo_T));
-  const char *expr;
   typval_T tv;
   list_T *l;
   const bool skip = !(evalarg->eval_flags & EVAL_EVALUATE);
 
   *errp = true;  // Default: there is an error.
 
-  expr = skip_var_list(arg, &fi->fi_varcount, &fi->fi_semicolon);
+  const char *expr = skip_var_list(arg, &fi->fi_varcount, &fi->fi_semicolon);
   if (expr == NULL) {
     return fi;
   }
@@ -2005,13 +2004,12 @@ void set_context_for_expression(expand_T *xp, char *arg, cmdidx_T cmdidx)
   FUNC_ATTR_NONNULL_ALL
 {
   bool got_eq = false;
-  char *p;
 
   if (cmdidx == CMD_let || cmdidx == CMD_const) {
     xp->xp_context = EXPAND_USER_VARS;
     if (strpbrk(arg, "\"'+-*/%.=!?~|&$([<>,#") == NULL) {
       // ":let var1 var2 ...": find last space.
-      for (p = arg + strlen(arg); p >= arg;) {
+      for (char *p = arg + strlen(arg); p >= arg;) {
         xp->xp_pattern = p;
         MB_PTR_BACK(arg, p);
         if (ascii_iswhite(*p)) {
@@ -2343,14 +2341,12 @@ void clear_evalarg(evalarg_T *evalarg, exarg_T *eap)
 /// @return OK or FAIL.
 int eval0(char *arg, typval_T *rettv, exarg_T *eap, evalarg_T *const evalarg)
 {
-  int ret;
-  char *p;
   const int did_emsg_before = did_emsg;
   const int called_emsg_before = called_emsg;
   bool end_error = false;
 
-  p = skipwhite(arg);
-  ret = eval1(&p, rettv, evalarg);
+  char *p = skipwhite(arg);
+  int ret = eval1(&p, rettv, evalarg);
 
   if (ret != FAIL) {
     end_error = !ends_excmd(*p);
@@ -7239,10 +7235,9 @@ void set_vim_var_tv(const VimVarIndex idx, typval_T *const tv)
 void set_argv_var(char **argv, int argc)
 {
   list_T *l = tv_list_alloc(argc);
-  int i;
 
   tv_list_set_lock(l, VAR_FIXED);
-  for (i = 0; i < argc; i++) {
+  for (int i = 0; i < argc; i++) {
     tv_list_append_string(l, (const char *const)argv[i], -1);
     TV_LIST_ITEM_TV(tv_list_last(l))->v_lock = VAR_FIXED;
   }
diff --git a/src/nvim/ex_cmds.c b/src/nvim/ex_cmds.c
index 19d1bdc8e6..94f981dc2b 100644
--- a/src/nvim/ex_cmds.c
+++ b/src/nvim/ex_cmds.c
@@ -238,12 +238,8 @@ void do_ascii(exarg_T *eap)
 /// ":left", ":center" and ":right": align text.
 void ex_align(exarg_T *eap)
 {
-  pos_T save_curpos;
-  int len;
   int indent = 0;
   int new_indent;
-  int has_tab;
-  int width;
 
   if (curwin->w_p_rl) {
     // switch left and right aligning
@@ -254,8 +250,8 @@ void ex_align(exarg_T *eap)
     }
   }
 
-  width = atoi(eap->arg);
-  save_curpos = curwin->w_cursor;
+  int width = atoi(eap->arg);
+  pos_T save_curpos = curwin->w_cursor;
   if (eap->cmdidx == CMD_left) {    // width is used for new indent
     if (width >= 0) {
       indent = width;
@@ -284,8 +280,8 @@ void ex_align(exarg_T *eap)
     if (eap->cmdidx == CMD_left) {              // left align
       new_indent = indent;
     } else {
-      has_tab = false;          // avoid uninit warnings
-      len = linelen(eap->cmdidx == CMD_right ? &has_tab : NULL) - get_indent();
+      int has_tab = false;          // avoid uninit warnings
+      int len = linelen(eap->cmdidx == CMD_right ? &has_tab : NULL) - get_indent();
 
       if (len <= 0) {                           // skip blank lines
         continue;
@@ -328,26 +324,23 @@ void ex_align(exarg_T *eap)
 /// @return  the length of the current line, excluding trailing white space.
 static int linelen(int *has_tab)
 {
-  char *line;
-  char *first;
   char *last;
-  int len;
 
   // Get the line.  If it's empty bail out early (could be the empty string
   // for an unloaded buffer).
-  line = get_cursor_line_ptr();
+  char *line = get_cursor_line_ptr();
   if (*line == NUL) {
     return 0;
   }
   // find the first non-blank character
-  first = skipwhite(line);
+  char *first = skipwhite(line);
 
   // find the character after the last non-blank character
   for (last = first + strlen(first);
        last > first && ascii_iswhite(last[-1]); last--) {}
   char save = *last;
   *last = NUL;
-  len = linetabsize_str(line);  // Get line length.
+  int len = linetabsize_str(line);  // Get line length.
   if (has_tab != NULL) {        // Check for embedded TAB.
     *has_tab = vim_strchr(first, TAB) != NULL;
   }
@@ -451,19 +444,11 @@ static int sort_compare(const void *s1, const void *s2)
 void ex_sort(exarg_T *eap)
 {
   regmatch_T regmatch;
-  int len;
   linenr_T lnum;
   int maxlen = 0;
   size_t count = (size_t)(eap->line2 - eap->line1) + 1;
   size_t i;
-  char *p;
-  char *s;
-  char *s2;
-  char c;                             // temporary character storage
   bool unique = false;
-  linenr_T deleted;
-  colnr_T start_col;
-  colnr_T end_col;
   int sort_what = 0;
 
   // Sorting one line is really quick!
@@ -483,7 +468,7 @@ void ex_sort(exarg_T *eap)
   size_t format_found = 0;
   bool change_occurred = false;   // Buffer contents changed.
 
-  for (p = eap->arg; *p != NUL; p++) {
+  for (char *p = eap->arg; *p != NUL; p++) {
     if (ascii_iswhite(*p)) {
       // Skip
     } else if (*p == 'i') {
@@ -516,7 +501,7 @@ void ex_sort(exarg_T *eap)
       eap->nextcmd = check_nextcmd(p);
       break;
     } else if (!ASCII_ISALPHA(*p) && regmatch.regprog == NULL) {
-      s = skip_regexp_err(p + 1, *p, true);
+      char *s = skip_regexp_err(p + 1, *p, true);
       if (s == NULL) {
         goto sortend;
       }
@@ -559,14 +544,14 @@ void ex_sort(exarg_T *eap)
   // matching and number conversion only has to be done once per line.
   // Also get the longest line length for allocating "sortbuf".
   for (lnum = eap->line1; lnum <= eap->line2; lnum++) {
-    s = ml_get(lnum);
-    len = (int)strlen(s);
+    char *s = ml_get(lnum);
+    int len = (int)strlen(s);
     if (maxlen < len) {
       maxlen = len;
     }
 
-    start_col = 0;
-    end_col = len;
+    colnr_T start_col = 0;
+    colnr_T end_col = len;
     if (regmatch.regprog != NULL && vim_regexec(&regmatch, s, 0)) {
       if (sort_rx) {
         start_col = (colnr_T)(regmatch.startp[0] - s);
@@ -581,11 +566,11 @@ void ex_sort(exarg_T *eap)
     if (sort_nr || sort_flt) {
       // Make sure vim_str2nr() doesn't read any digits past the end
       // of the match, by temporarily terminating the string there
-      s2 = s + end_col;
-      c = *s2;
+      char *s2 = s + end_col;
+      char c = *s2;  // temporary character storage
       *s2 = NUL;
       // Sorting on number: Store the number itself.
-      p = s + start_col;
+      char *p = s + start_col;
       if (sort_nr) {
         if (sort_what & STR2NR_HEX) {
           s = skiptohex(p);
@@ -660,7 +645,7 @@ void ex_sort(exarg_T *eap)
       change_occurred = true;
     }
 
-    s = ml_get(get_lnum);
+    char *s = ml_get(get_lnum);
     size_t bytelen = strlen(s) + 1;  // include EOL in bytelen
     old_count += (bcount_t)bytelen;
     if (!unique || i == 0 || string_compare(s, sortbuf1) != 0) {
@@ -688,7 +673,7 @@ void ex_sort(exarg_T *eap)
   }
 
   // Adjust marks for deleted (or added) lines and prepare for displaying.
-  deleted = (linenr_T)count - (lnum - eap->line2);
+  linenr_T deleted = (linenr_T)count - (lnum - eap->line2);
   if (deleted > 0) {
     mark_adjust(eap->line2 - deleted, eap->line2, MAXLNUM, -deleted, kExtmarkNOOP);
     msgmore(-deleted);
@@ -954,14 +939,9 @@ void do_bang(int addr_count, exarg_T *eap, bool forceit, bool do_in, bool do_out
   linenr_T line2 = eap->line2;        // end of range
   char *newcmd = NULL;              // the new command
   bool free_newcmd = false;           // need to free() newcmd
-  char *t;
-  char *p;
-  char *trailarg;
   int scroll_save = msg_scroll;
 
-  //
   // Disallow shell commands in secure mode
-  //
   if (check_secure()) {
     return;
   }
@@ -977,7 +957,7 @@ void do_bang(int addr_count, exarg_T *eap, bool forceit, bool do_in, bool do_out
   bool ins_prevcmd = forceit;
 
   // Skip leading white space to avoid a strange error with some shells.
-  trailarg = skipwhite(arg);
+  char *trailarg = skipwhite(arg);
   do {
     size_t len = strlen(trailarg) + 1;
     if (newcmd != NULL) {
@@ -990,7 +970,7 @@ void do_bang(int addr_count, exarg_T *eap, bool forceit, bool do_in, bool do_out
       }
       len += strlen(prevcmd);
     }
-    t = xmalloc(len);
+    char *t = xmalloc(len);
     *t = NUL;
     if (newcmd != NULL) {
       STRCAT(t, newcmd);
@@ -998,7 +978,7 @@ void do_bang(int addr_count, exarg_T *eap, bool forceit, bool do_in, bool do_out
     if (ins_prevcmd) {
       STRCAT(t, prevcmd);
     }
-    p = t + strlen(t);
+    char *p = t + strlen(t);
     STRCAT(t, trailarg);
     xfree(newcmd);
     newcmd = t;
@@ -1099,10 +1079,6 @@ static void do_filter(linenr_T line1, linenr_T line2, exarg_T *eap, char *cmd, b
 {
   char *itmp = NULL;
   char *otmp = NULL;
-  linenr_T linecount;
-  linenr_T read_linecount;
-  pos_T cursor_save;
-  char *cmd_buf;
   buf_T *old_curbuf = curbuf;
   int shell_flags = 0;
   const pos_T orig_start = curbuf->b_op_start;
@@ -1118,8 +1094,8 @@ static void do_filter(linenr_T line1, linenr_T line2, exarg_T *eap, char *cmd, b
   // regions of the buffer for foldUpdate(), linecount, etc.
   cmdmod.cmod_flags &= ~CMOD_LOCKMARKS;
 
-  cursor_save = curwin->w_cursor;
-  linecount = line2 - line1 + 1;
+  pos_T cursor_save = curwin->w_cursor;
+  linenr_T linecount = line2 - line1 + 1;
   curwin->w_cursor.lnum = line1;
   curwin->w_cursor.col = 0;
   changed_line_abv_curs();
@@ -1184,7 +1160,7 @@ static void do_filter(linenr_T line1, linenr_T line2, exarg_T *eap, char *cmd, b
   }
 
   // Create the shell command in allocated memory.
-  cmd_buf = make_filter_cmd(cmd, itmp, otmp);
+  char *cmd_buf = make_filter_cmd(cmd, itmp, otmp);
   ui_cursor_goto(Rows - 1, 0);
 
   if (do_out) {
@@ -1194,7 +1170,7 @@ static void do_filter(linenr_T line1, linenr_T line2, exarg_T *eap, char *cmd, b
     }
     redraw_curbuf_later(UPD_VALID);
   }
-  read_linecount = curbuf->b_ml.ml_line_count;
+  linenr_T read_linecount = curbuf->b_ml.ml_line_count;
 
   // Pass on the kShellOptDoOut flag when the output is being redirected.
   call_shell(cmd_buf, (ShellOpts)(kShellOptFilter | shell_flags), NULL);
@@ -1534,10 +1510,7 @@ void print_line(linenr_T lnum, int use_number, int list)
 
 int rename_buffer(char *new_fname)
 {
-  char *fname, *sfname, *xfname;
-  buf_T *buf;
-
-  buf = curbuf;
+  buf_T *buf = curbuf;
   apply_autocmds(EVENT_BUFFILEPRE, NULL, NULL, false, curbuf);
   // buffer changed, don't change name now
   if (buf != curbuf) {
@@ -1551,9 +1524,9 @@ int rename_buffer(char *new_fname)
   // name, which will become the alternate file name.
   // But don't set the alternate file name if the buffer didn't have a
   // name.
-  fname = curbuf->b_ffname;
-  sfname = curbuf->b_sfname;
-  xfname = curbuf->b_fname;
+  char *fname = curbuf->b_ffname;
+  char *sfname = curbuf->b_sfname;
+  char *xfname = curbuf->b_fname;
   curbuf->b_ffname = NULL;
   curbuf->b_sfname = NULL;
   if (setfname(curbuf, new_fname, NULL, true) == FAIL) {
@@ -1647,7 +1620,6 @@ int do_write(exarg_T *eap)
 {
   int other;
   char *fname = NULL;            // init to shut up gcc
-  char *ffname;
   int retval = FAIL;
   char *free_fname = NULL;
   buf_T *alt_buf = NULL;
@@ -1657,7 +1629,7 @@ int do_write(exarg_T *eap)
     return FAIL;
   }
 
-  ffname = eap->arg;
+  char *ffname = eap->arg;
   if (*ffname == NUL) {
     if (eap->cmdidx == CMD_saveas) {
       emsg(_(e_argreq));
@@ -2931,12 +2903,9 @@ void ex_change(exarg_T *eap)
 
 void ex_z(exarg_T *eap)
 {
-  char *x;
   int64_t bigness;
-  char *kind;
   int minus = 0;
   linenr_T start, end, curs, i;
-  int j;
   linenr_T lnum = eap->line2;
 
   // Vi compatible: ":z!" uses display height, without a count uses
@@ -2952,8 +2921,8 @@ void ex_z(exarg_T *eap)
     bigness = 1;
   }
 
-  x = eap->arg;
-  kind = x;
+  char *x = eap->arg;
+  char *kind = x;
   if (*kind == '-' || *kind == '+' || *kind == '='
       || *kind == '^' || *kind == '.') {
     x++;
@@ -3041,7 +3010,7 @@ void ex_z(exarg_T *eap)
     if (minus && i == lnum) {
       msg_putchar('\n');
 
-      for (j = 1; j < Columns; j++) {
+      for (int j = 1; j < Columns; j++) {
         msg_putchar('-');
       }
     }
@@ -3051,7 +3020,7 @@ void ex_z(exarg_T *eap)
     if (minus && i == lnum) {
       msg_putchar('\n');
 
-      for (j = 1; j < Columns; j++) {
+      for (int j = 1; j < Columns; j++) {
         msg_putchar('-');
       }
     }
@@ -4386,7 +4355,6 @@ void ex_global(exarg_T *eap)
   char *pat;
   regmmatch_T regmatch;
   int match;
-  int which_pat;
 
   // When nesting the command works on one line.  This allows for
   // ":g/found/v/notfound/command".
@@ -4403,7 +4371,7 @@ void ex_global(exarg_T *eap)
     type = (uint8_t)(*eap->cmd);
   }
   cmd = eap->arg;
-  which_pat = RE_LAST;              // default: use last used regexp
+  int which_pat = RE_LAST;              // default: use last used regexp
 
   // undocumented vi feature:
   //    "\/" and "\?": use previous search pattern.
diff --git a/src/nvim/ex_cmds2.c b/src/nvim/ex_cmds2.c
index 10b0fd6236..a99563bd9c 100644
--- a/src/nvim/ex_cmds2.c
+++ b/src/nvim/ex_cmds2.c
@@ -101,7 +101,6 @@ void ex_perldo(exarg_T *eap)
 /// @return FAIL for failure, OK otherwise
 int autowrite(buf_T *buf, int forceit)
 {
-  int r;
   bufref_T bufref;
 
   if (!(p_aw || p_awa) || !p_write
@@ -111,7 +110,7 @@ int autowrite(buf_T *buf, int forceit)
     return FAIL;
   }
   set_bufref(&bufref, buf);
-  r = buf_write_all(buf, forceit);
+  int r = buf_write_all(buf, forceit);
 
   // Writing may succeed but the buffer still changed, e.g., when there is a
   // conversion error.  We do want to return FAIL then.
@@ -273,9 +272,7 @@ bool can_abandon(buf_T *buf, int forceit)
 /// Add a buffer number to "bufnrs", unless it's already there.
 static void add_bufnum(int *bufnrs, int *bufnump, int nr)
 {
-  int i;
-
-  for (i = 0; i < *bufnump; i++) {
+  for (int i = 0; i < *bufnump; i++) {
     if (bufnrs[i] == nr) {
       return;
     }
@@ -296,11 +293,9 @@ static void add_bufnum(int *bufnrs, int *bufnump, int nr)
 bool check_changed_any(bool hidden, bool unload)
 {
   bool ret = false;
-  int save;
   int i;
   int bufnum = 0;
   size_t bufcount = 0;
-  int *bufnrs;
 
   // Make a list of all buffers, with the most important ones first.
   FOR_ALL_BUFFERS(buf) {
@@ -311,7 +306,7 @@ bool check_changed_any(bool hidden, bool unload)
     return false;
   }
 
-  bufnrs = xmalloc(sizeof(*bufnrs) * bufcount);
+  int *bufnrs = xmalloc(sizeof(*bufnrs) * bufcount);
 
   // curbuf
   bufnrs[bufnum++] = curbuf->b_fnum;
@@ -379,7 +374,7 @@ bool check_changed_any(bool hidden, bool unload)
         ? semsg(_("E947: Job still running in buffer \"%s\""), buf->b_fname)
         : semsg(_("E162: No write since last change for buffer \"%s\""),
                 buf_spname(buf) != NULL ? buf_spname(buf) : buf->b_fname)) {
-      save = no_wait_return;
+      int save = no_wait_return;
       no_wait_return = false;
       wait_return(false);
       no_wait_return = save;
@@ -429,12 +424,11 @@ int check_fname(void)
 /// @return  FAIL for failure, OK otherwise
 int buf_write_all(buf_T *buf, int forceit)
 {
-  int retval;
   buf_T *old_curbuf = curbuf;
 
-  retval = (buf_write(buf, buf->b_ffname, buf->b_fname,
-                      1, buf->b_ml.ml_line_count, NULL,
-                      false, forceit, true, false));
+  int retval = (buf_write(buf, buf->b_ffname, buf->b_fname,
+                          1, buf->b_ml.ml_line_count, NULL,
+                          false, forceit, true, false));
   if (curbuf != old_curbuf) {
     msg_source(HL_ATTR(HLF_W));
     msg(_("Warning: Entered other buffer unexpectedly (check autocommands)"), 0);
@@ -684,9 +678,7 @@ void ex_listdo(exarg_T *eap)
 /// ":compiler[!] {name}"
 void ex_compiler(exarg_T *eap)
 {
-  char *buf;
   char *old_cur_comp = NULL;
-  char *p;
 
   if (*eap->arg == NUL) {
     // List all compiler scripts.
@@ -696,7 +688,7 @@ void ex_compiler(exarg_T *eap)
   }
 
   size_t bufsize = strlen(eap->arg) + 14;
-  buf = xmalloc(bufsize);
+  char *buf = xmalloc(bufsize);
 
   if (eap->forceit) {
     // ":compiler! {name}" sets global options
@@ -726,7 +718,7 @@ void ex_compiler(exarg_T *eap)
   do_cmdline_cmd(":delcommand CompilerSet");
 
   // Set "b:current_compiler" from "current_compiler".
-  p = get_var_value("g:current_compiler");
+  char *p = get_var_value("g:current_compiler");
   if (p != NULL) {
     set_internal_string_var("b:current_compiler", p);
   }
@@ -809,7 +801,6 @@ static void script_host_do_range(char *name, exarg_T *eap)
 void ex_drop(exarg_T *eap)
 {
   bool split = false;
-  buf_T *buf;
 
   // Check if the first argument is already being edited in a window.  If
   // so, jump to that window.
@@ -837,7 +828,7 @@ void ex_drop(exarg_T *eap)
   // ":drop file ...": Edit the first argument.  Jump to an existing
   // window if possible, edit in current window if the current buffer
   // can be abandoned, otherwise open a new window.
-  buf = buflist_findnr(ARGLIST[0].ae_fnum);
+  buf_T *buf = buflist_findnr(ARGLIST[0].ae_fnum);
 
   FOR_ALL_TAB_WINDOWS(tp, wp) {
     if (wp->w_buffer == buf) {
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index 88c33088bd..13043930b2 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -333,16 +333,12 @@ int do_cmdline(char *cmdline, LineGetter fgetline, void *cookie, int flags)
   linenr_T *breakpoint = NULL;          // ptr to breakpoint field in cookie
   int *dbg_tick = NULL;                 // ptr to dbg_tick field in cookie
   struct dbg_stuff debug_saved;         // saved things for debug mode
-  int initial_trylevel;
-  msglist_T **saved_msg_list = NULL;
   msglist_T *private_msg_list;
 
   // "fgetline" and "cookie" passed to do_one_cmd()
   char *(*cmd_getline)(int, void *, int, bool);
   void *cmd_cookie;
   struct loop_cookie cmd_loop_cookie;
-  void *real_cookie;
-  int getline_is_func;
   static int call_depth = 0;            // recursiveness
 
   // For every pair of do_cmdline()/do_one_cmd() calls, use an extra memory
@@ -351,7 +347,7 @@ int do_cmdline(char *cmdline, LineGetter fgetline, void *cookie, int flags)
   // combine the messages stored by an earlier invocation of do_one_cmd()
   // with the command name of the later one.  This would happen when
   // BufWritePost autocommands are executed after a write error.
-  saved_msg_list = msg_list;
+  msglist_T **saved_msg_list = msg_list;
   msg_list = &private_msg_list;
   private_msg_list = NULL;
 
@@ -371,10 +367,10 @@ int do_cmdline(char *cmdline, LineGetter fgetline, void *cookie, int flags)
 
   ga_init(&lines_ga, (int)sizeof(wcmd_T), 10);
 
-  real_cookie = getline_cookie(fgetline, cookie);
+  void *real_cookie = getline_cookie(fgetline, cookie);
 
   // Inside a function use a higher nesting level.
-  getline_is_func = getline_equal(fgetline, cookie, get_func_line);
+  bool getline_is_func = getline_equal(fgetline, cookie, get_func_line);
   if (getline_is_func && ex_nesting_level == func_level(real_cookie)) {
     ex_nesting_level++;
   }
@@ -406,7 +402,7 @@ int do_cmdline(char *cmdline, LineGetter fgetline, void *cookie, int flags)
     CLEAR_FIELD(debug_saved);
   }
 
-  initial_trylevel = trylevel;
+  int initial_trylevel = trylevel;
 
   // "did_throw" will be set to true when an exception is being thrown.
   did_throw = false;
@@ -5328,8 +5324,6 @@ static void ex_edit(exarg_T *eap)
 /// @param old_curwin  curwin before doing a split or NULL
 void do_exedit(exarg_T *eap, win_T *old_curwin)
 {
-  int n;
-
   // ":vi" command ends Ex mode.
   if (exmode_active && (eap->cmdidx == CMD_visual
                         || eap->cmdidx == CMD_view)) {
@@ -5380,7 +5374,7 @@ void do_exedit(exarg_T *eap, win_T *old_curwin)
     if (*eap->arg != NUL && text_or_buf_locked()) {
       return;
     }
-    n = readonlymode;
+    int n = readonlymode;
     if (eap->cmdidx == CMD_view || eap->cmdidx == CMD_sview) {
       readonlymode = true;
     } else if (eap->cmdidx == CMD_enew) {
@@ -5428,7 +5422,7 @@ void do_exedit(exarg_T *eap, win_T *old_curwin)
     if (eap->do_ecmd_cmd != NULL) {
       do_cmdline_cmd(eap->do_ecmd_cmd);
     }
-    n = curwin->w_arg_idx_invalid;
+    int n = curwin->w_arg_idx_invalid;
     check_arg_idx(curwin);
     if (n != curwin->w_arg_idx_invalid) {
       maketitle();
@@ -6498,8 +6492,7 @@ static void ex_normal(exarg_T *eap)
 
     // Count the number of characters to be escaped.
     int l;
-    char *p;
-    for (p = eap->arg; *p != NUL; p++) {
+    for (char *p = eap->arg; *p != NUL; p++) {
       for (l = utfc_ptr2len(p) - 1; l > 0; l--) {
         if (*++p == (char)K_SPECIAL) {  // trailbyte K_SPECIAL
           len += 2;
@@ -6509,7 +6502,7 @@ static void ex_normal(exarg_T *eap)
     if (len > 0) {
       arg = xmalloc(strlen(eap->arg) + (size_t)len + 1);
       len = 0;
-      for (p = eap->arg; *p != NUL; p++) {
+      for (char *p = eap->arg; *p != NUL; p++) {
         arg[len++] = *p;
         for (l = utfc_ptr2len(p) - 1; l > 0; l--) {
           arg[len++] = *++p;
diff --git a/src/nvim/ex_eval.c b/src/nvim/ex_eval.c
index 60dd5a076e..00abade4b0 100644
--- a/src/nvim/ex_eval.c
+++ b/src/nvim/ex_eval.c
@@ -156,7 +156,6 @@ bool cause_errthrow(const char *mesg, bool multiline, bool severe, bool *ignore)
   FUNC_ATTR_NONNULL_ALL
 {
   msglist_T *elem;
-  msglist_T **plist;
 
   // Do nothing when displaying the interrupt message or reporting an
   // uncaught exception (which has already been discarded then) at the top
@@ -237,7 +236,7 @@ bool cause_errthrow(const char *mesg, bool multiline, bool severe, bool *ignore)
     // returned.  -  Throw only the first of several errors in a row, except
     // a severe error is following.
     if (msg_list != NULL) {
-      plist = msg_list;
+      msglist_T **plist = msg_list;
       while (*plist != NULL) {
         plist = &(*plist)->next;
       }
@@ -249,10 +248,8 @@ bool cause_errthrow(const char *mesg, bool multiline, bool severe, bool *ignore)
       elem->throw_msg = NULL;
       *plist = elem;
       if (plist == msg_list || severe) {
-        char *tmsg;
-
         // Skip the extra "Vim " prefix for message "E458".
-        tmsg = elem->msg;
+        char *tmsg = elem->msg;
         if (strncmp(tmsg, "Vim E", 5) == 0
             && ascii_isdigit(tmsg[5])
             && ascii_isdigit(tmsg[6])
@@ -277,10 +274,9 @@ bool cause_errthrow(const char *mesg, bool multiline, bool severe, bool *ignore)
 /// Free a "msg_list" and the messages it contains.
 static void free_msglist(msglist_T *l)
 {
-  msglist_T *next;
   msglist_T *messages = l;
   while (messages != NULL) {
-    next = messages->next;
+    msglist_T *next = messages->next;
     xfree(messages->msg);
     xfree(messages->sfile);
     xfree(messages);
@@ -376,13 +372,12 @@ int do_intthrow(cstack_T *cstack)
 /// Get an exception message that is to be stored in current_exception->value.
 char *get_exception_string(void *value, except_type_T type, char *cmdname, int *should_free)
 {
-  char *ret, *mesg;
+  char *ret;
 
   if (type == ET_ERROR) {
-    char *p;
     char *val;
     *should_free = true;
-    mesg = ((msglist_T *)value)->throw_msg;
+    char *mesg = ((msglist_T *)value)->throw_msg;
     if (cmdname != NULL && *cmdname != NUL) {
       size_t cmdlen = strlen(cmdname);
       ret = xstrnsave("Vim(", 4 + cmdlen + 2 + strlen(mesg));
@@ -397,7 +392,7 @@ char *get_exception_string(void *value, except_type_T type, char *cmdname, int *
     // msg_add_fname may have been used to prefix the message with a file
     // name in quotes.  In the exception value, put the file name in
     // parentheses and move it to the end.
-    for (p = mesg;; p++) {
+    for (char *p = mesg;; p++) {
       if (*p == NUL
           || (*p == 'E'
               && ascii_isdigit(p[1])
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 912eab2a31..69025d81c7 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -249,14 +249,9 @@ static bool do_incsearch_highlighting(int firstc, int *search_delim, incsearch_s
                                       int *skiplen, int *patlen)
   FUNC_ATTR_NONNULL_ALL
 {
-  char *cmd;
   char *p;
   bool delim_optional = false;
-  int delim;
-  char *end;
   const char *dummy;
-  pos_T save_cursor;
-  bool use_last_pat;
   bool retval = false;
   magic_T magic = 0;
 
@@ -290,7 +285,7 @@ static bool do_incsearch_highlighting(int firstc, int *search_delim, incsearch_s
   cmdmod_T dummy_cmdmod;
   parse_command_modifiers(&ea, &dummy, &dummy_cmdmod, true);
 
-  cmd = skip_range(ea.cmd, NULL);
+  char *cmd = skip_range(ea.cmd, NULL);
   if (vim_strchr("sgvl", (uint8_t)(*cmd)) == NULL) {
     goto theend;
   }
@@ -341,11 +336,11 @@ static bool do_incsearch_highlighting(int firstc, int *search_delim, incsearch_s
   }
 
   p = skipwhite(p);
-  delim = (delim_optional && vim_isIDc((uint8_t)(*p))) ? ' ' : *p++;
+  int delim = (delim_optional && vim_isIDc((uint8_t)(*p))) ? ' ' : *p++;
   *search_delim = delim;
-  end = skip_regexp_ex(p, delim, magic_isset(), NULL, NULL, &magic);
+  char *end = skip_regexp_ex(p, delim, magic_isset(), NULL, NULL, &magic);
 
-  use_last_pat = end == p && *end == delim;
+  bool use_last_pat = end == p && *end == delim;
   if (end == p && !use_last_pat) {
     goto theend;
   }
@@ -366,7 +361,7 @@ static bool do_incsearch_highlighting(int firstc, int *search_delim, incsearch_s
   *patlen = (int)(end - p);
 
   // parse the address range
-  save_cursor = curwin->w_cursor;
+  pos_T save_cursor = curwin->w_cursor;
   curwin->w_cursor = s->search_start;
   parse_cmd_address(&ea, &dummy, true);
   if (ea.addr_count > 0) {
@@ -395,10 +390,7 @@ theend:
 static void may_do_incsearch_highlighting(int firstc, int count, incsearch_state_T *s)
 {
   pos_T end_pos;
-  proftime_T tm;
   int skiplen, patlen;
-  char next_char;
-  bool use_last_pat;
   int search_delim;
 
   // Parsing range may already set the last search pattern.
@@ -435,9 +427,9 @@ static void may_do_incsearch_highlighting(int firstc, int count, incsearch_state
   int found;  // do_search() result
 
   // Use the previous pattern for ":s//".
-  next_char = ccline.cmdbuff[skiplen + patlen];
-  use_last_pat = patlen == 0 && skiplen > 0
-                 && ccline.cmdbuff[skiplen - 1] == next_char;
+  char next_char = ccline.cmdbuff[skiplen + patlen];
+  bool use_last_pat = patlen == 0 && skiplen > 0
+                      && ccline.cmdbuff[skiplen - 1] == next_char;
 
   // If there is no pattern, don't do anything.
   if (patlen == 0 && !use_last_pat) {
@@ -450,7 +442,7 @@ static void may_do_incsearch_highlighting(int firstc, int count, incsearch_state
     ui_flush();
     emsg_off++;            // So it doesn't beep if bad expr
     // Set the time limit to half a second.
-    tm = profile_setlimit(500);
+    proftime_T tm = profile_setlimit(500);
     if (!p_hls) {
       search_flags += SEARCH_KEEP;
     }
@@ -1408,7 +1400,6 @@ static int may_do_command_line_next_incsearch(int firstc, int count, incsearch_s
   pos_T t;
   char *pat;
   int search_flags = SEARCH_NOOF;
-  char save;
 
   if (search_delim == ccline.cmdbuff[skiplen]) {
     pat = last_search_pattern();
@@ -1437,7 +1428,7 @@ static int may_do_command_line_next_incsearch(int firstc, int count, incsearch_s
     search_flags += SEARCH_KEEP;
   }
   emsg_off++;
-  save = pat[patlen];
+  char save = pat[patlen];
   pat[patlen] = NUL;
   int found = searchit(curwin, curbuf, &t, NULL,
                        next_match ? FORWARD : BACKWARD,
@@ -3971,11 +3962,9 @@ void escape_fname(char **pp)
 /// If 'orig_pat' starts with "~/", replace the home directory with "~".
 void tilde_replace(char *orig_pat, int num_files, char **files)
 {
-  char *p;
-
   if (orig_pat[0] == '~' && vim_ispathsep(orig_pat[1])) {
     for (int i = 0; i < num_files; i++) {
-      p = home_replace_save(NULL, files[i]);
+      char *p = home_replace_save(NULL, files[i]);
       xfree(files[i]);
       files[i] = p;
     }
diff --git a/src/nvim/ex_session.c b/src/nvim/ex_session.c
index 3807436efb..aa85696b51 100644
--- a/src/nvim/ex_session.c
+++ b/src/nvim/ex_session.c
@@ -60,11 +60,9 @@ static int put_view_curpos(FILE *fd, const win_T *wp, char *spaces)
 
 static int ses_winsizes(FILE *fd, int restore_size, win_T *tab_firstwin)
 {
-  win_T *wp;
-
   if (restore_size && (ssop_flags & SSOP_WINSIZE)) {
     int n = 0;
-    for (wp = tab_firstwin; wp != NULL; wp = wp->w_next) {
+    for (win_T *wp = tab_firstwin; wp != NULL; wp = wp->w_next) {
       if (!ses_do_win(wp)) {
         continue;
       }
@@ -104,7 +102,6 @@ static int ses_winsizes(FILE *fd, int restore_size, win_T *tab_firstwin)
 /// @return  FAIL when writing the commands to "fd" fails.
 static int ses_win_rec(FILE *fd, frame_T *fr)
 {
-  frame_T *frc;
   int count = 0;
 
   if (fr->fr_layout == FR_LEAF) {
@@ -113,7 +110,7 @@ static int ses_win_rec(FILE *fd, frame_T *fr)
 
   // Find first frame that's not skipped and then create a window for
   // each following one (first frame is already there).
-  frc = ses_skipframe(fr->fr_child);
+  frame_T *frc = ses_skipframe(fr->fr_child);
   if (frc != NULL) {
     while ((frc = ses_skipframe(frc->fr_next)) != NULL) {
       // Make window as big as possible so that we have lots of room
@@ -315,14 +312,12 @@ static int ses_put_fname(FILE *fd, char *name, unsigned *flagp)
 /// @param current_arg_idx  current argument index of the window, use -1 if unknown
 static int put_view(FILE *fd, win_T *wp, int add_edit, unsigned *flagp, int current_arg_idx)
 {
-  win_T *save_curwin;
   int f;
-  int do_cursor;
   int did_next = false;
 
   // Always restore cursor position for ":mksession".  For ":mkview" only
   // when 'viewoptions' contains "cursor".
-  do_cursor = (flagp == &ssop_flags || *flagp & SSOP_CURSOR);
+  int do_cursor = (flagp == &ssop_flags || *flagp & SSOP_CURSOR);
 
   // Local argument list.
   if (wp->w_alist == &global_alist) {
@@ -428,7 +423,7 @@ static int put_view(FILE *fd, win_T *wp, int add_edit, unsigned *flagp, int curr
   // used and 'sessionoptions' doesn't include "nvim/options".
   // Some folding options are always stored when "folds" is included,
   // otherwise the folds would not be restored correctly.
-  save_curwin = curwin;
+  win_T *save_curwin = curwin;
   curwin = wp;
   curbuf = curwin->w_buffer;
   if (*flagp & (SSOP_OPTIONS | SSOP_LOCALOPTIONS)) {
@@ -534,8 +529,6 @@ static int makeopens(FILE *fd, char *dirnow)
 {
   int only_save_windows = true;
   int restore_size = true;
-  win_T *wp;
-  char *sname;
   win_T *edited_win = NULL;
   win_T *tab_firstwin;
   frame_T *tab_topframe;
@@ -565,7 +558,7 @@ static int makeopens(FILE *fd, char *dirnow)
   if (ssop_flags & SSOP_SESDIR) {
     PUTLINE_FAIL("exe \"cd \" . escape(expand(\"<sfile>:p:h\"), ' ')");
   } else if (ssop_flags & SSOP_CURDIR) {
-    sname = home_replace_save(NULL, globaldir != NULL ? globaldir : dirnow);
+    char *sname = home_replace_save(NULL, globaldir != NULL ? globaldir : dirnow);
     char *fname_esc = ses_escape_fname(sname, &ssop_flags);
     if (fprintf(fd, "cd %s\n", fname_esc) < 0) {
       xfree(fname_esc);
@@ -691,7 +684,7 @@ static int makeopens(FILE *fd, char *dirnow)
     // Before creating the window layout, try loading one file.  If this
     // is aborted we don't end up with a number of useless windows.
     // This may have side effects! (e.g., compressed or network file).
-    for (wp = tab_firstwin; wp != NULL; wp = wp->w_next) {
+    for (win_T *wp = tab_firstwin; wp != NULL; wp = wp->w_next) {
       if (ses_do_win(wp)
           && wp->w_buffer->b_ffname != NULL
           && !bt_help(wp->w_buffer)
@@ -732,7 +725,7 @@ static int makeopens(FILE *fd, char *dirnow)
     // Check if window sizes can be restored (no windows omitted).
     // Remember the window number of the current window after restoring.
     int nr = 0;
-    for (wp = tab_firstwin; wp != NULL; wp = wp->w_next) {
+    for (win_T *wp = tab_firstwin; wp != NULL; wp = wp->w_next) {
       if (ses_do_win(wp)) {
         nr++;
       } else {
@@ -781,7 +774,7 @@ static int makeopens(FILE *fd, char *dirnow)
     }
 
     // Restore the view of the window (options, file, cursor, etc.).
-    for (wp = tab_firstwin; wp != NULL; wp = wp->w_next) {
+    for (win_T *wp = tab_firstwin; wp != NULL; wp = wp->w_next) {
       if (!ses_do_win(wp)) {
         continue;
       }
diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index 3010ded1d0..e89bb41745 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -87,7 +87,6 @@ static const char *e_auchangedbuf = N_("E812: Autocommands changed buffer or buf
 
 void filemess(buf_T *buf, char *name, char *s, int attr)
 {
-  int msg_scroll_save;
   int prev_msg_col = msg_col;
 
   if (msg_silent != 0) {
@@ -102,7 +101,7 @@ void filemess(buf_T *buf, char *name, char *s, int attr)
   // For the first message may have to start a new line.
   // For further ones overwrite the previous one, reset msg_scroll before
   // calling filemess().
-  msg_scroll_save = msg_scroll;
+  int msg_scroll_save = msg_scroll;
   if (shortmess(SHM_OVERALL) && !msg_listdo_overwrite && !exiting && p_verbose == 0) {
     msg_scroll = false;
   }
@@ -1323,7 +1322,6 @@ retry:
         // Reading UTF-8: Check if the bytes are valid UTF-8.
         for (p = (uint8_t *)ptr;; p++) {
           int todo = (int)(((uint8_t *)ptr + size) - p);
-          int l;
 
           if (todo <= 0) {
             break;
@@ -1333,7 +1331,7 @@ retry:
             // an incomplete character at the end though, the next
             // read() will get the next bytes, we'll check it
             // then.
-            l = utf_ptr2len_len((char *)p, todo);
+            int l = utf_ptr2len_len((char *)p, todo);
             if (l > todo && !incomplete_tail) {
               // Avoid retrying with a different encoding when
               // a truncated file is more likely, or attempting
@@ -1905,11 +1903,8 @@ bool is_dev_fd_file(char *fname)
 /// @param endp     end of more bytes read
 static linenr_T readfile_linenr(linenr_T linecnt, char *p, const char *endp)
 {
-  char *s;
-  linenr_T lnum;
-
-  lnum = curbuf->b_ml.ml_line_count - linecnt + 1;
-  for (s = p; s < endp; s++) {
+  linenr_T lnum = curbuf->b_ml.ml_line_count - linecnt + 1;
+  for (char *s = p; s < endp; s++) {
     if (*s == '\n') {
       lnum++;
     }
@@ -1977,7 +1972,6 @@ void set_forced_fenc(exarg_T *eap)
 static char *next_fenc(char **pp, bool *alloced)
   FUNC_ATTR_NONNULL_ALL FUNC_ATTR_NONNULL_RET
 {
-  char *p;
   char *r;
 
   *alloced = false;
@@ -1985,7 +1979,7 @@ static char *next_fenc(char **pp, bool *alloced)
     *pp = NULL;
     return "";
   }
-  p = vim_strchr(*pp, ',');
+  char *p = vim_strchr(*pp, ',');
   if (p == NULL) {
     r = enc_canonize(*pp);
     *pp += strlen(*pp);
@@ -2012,10 +2006,9 @@ static char *next_fenc(char **pp, bool *alloced)
 ///               Returns NULL if the conversion failed ("*fdp" is not set) .
 static char *readfile_charconvert(char *fname, char *fenc, int *fdp)
 {
-  char *tmpname;
   char *errmsg = NULL;
 
-  tmpname = vim_tempname();
+  char *tmpname = vim_tempname();
   if (tmpname == NULL) {
     errmsg = _("Can't find temp file for conversion");
   } else {
@@ -3246,12 +3239,10 @@ void write_lnum_adjust(linenr_T offset)
 /// unless when it looks like a URL.
 void forward_slash(char *fname)
 {
-  char *p;
-
   if (path_with_url(fname)) {
     return;
   }
-  for (p = fname; *p != NUL; p++) {
+  for (char *p = fname; *p != NUL; p++) {
     if (*p == '\\') {
       *p = '/';
     }
diff --git a/src/nvim/getchar.c b/src/nvim/getchar.c
index 47577714bb..df94822936 100644
--- a/src/nvim/getchar.c
+++ b/src/nvim/getchar.c
@@ -1952,7 +1952,6 @@ static int handle_mapping(int *keylenp, const bool *timedout, int *mapdepth)
   int mp_match_len = 0;
   int max_mlen = 0;
   int tb_c1;
-  int mlen;
   int keylen = *keylenp;
   int local_State = get_real_state();
   bool is_plug_map = false;
@@ -1986,6 +1985,7 @@ static int handle_mapping(int *keylenp, const bool *timedout, int *mapdepth)
       && State != MODE_ASKMORE
       && State != MODE_CONFIRM
       && !at_ins_compl_key()) {
+    int mlen;
     int nolmaplen;
     if (tb_c1 == K_SPECIAL) {
       nolmaplen = 2;
diff --git a/src/nvim/grid.c b/src/nvim/grid.c
index 15b648bb03..f21b7e3a90 100644
--- a/src/nvim/grid.c
+++ b/src/nvim/grid.c
@@ -549,8 +549,6 @@ void grid_line_flush_if_valid_row(void)
 void grid_fill(ScreenGrid *grid, int start_row, int end_row, int start_col, int end_col, int c1,
                int c2, int attr)
 {
-  schar_T sc;
-
   int row_off = 0, col_off = 0;
   grid_adjust(&grid, &row_off, &col_off);
   start_row += row_off;
@@ -594,7 +592,7 @@ void grid_fill(ScreenGrid *grid, int start_row, int end_row, int start_col, int
     }
 
     int col = start_col;
-    sc = schar_from_char(c1);
+    schar_T sc = schar_from_char(c1);
     for (col = start_col; col < end_col; col++) {
       size_t off = lineoff + (size_t)col;
       if (grid->chars[off] != sc || grid->attrs[off] != attr || rdb_flags & RDB_NODELTA) {
diff --git a/src/nvim/help.c b/src/nvim/help.c
index 3e7577505d..14dc7b6623 100644
--- a/src/nvim/help.c
+++ b/src/nvim/help.c
@@ -55,8 +55,6 @@ void ex_help(exarg_T *eap)
   char **matches;
   int empty_fnum = 0;
   int alt_fnum = 0;
-  buf_T *buf;
-  int len;
   const bool old_KeyTyped = KeyTyped;
 
   if (eap != NULL) {
@@ -105,7 +103,7 @@ void ex_help(exarg_T *eap)
   if (n != FAIL && lang != NULL) {
     // Find first item with the requested language.
     for (i = 0; i < num_matches; i++) {
-      len = (int)strlen(matches[i]);
+      int len = (int)strlen(matches[i]);
       if (len > 3 && matches[i][len - 3] == '@'
           && STRICMP(matches[i] + len - 2, lang) == 0) {
         break;
@@ -196,7 +194,7 @@ void ex_help(exarg_T *eap)
   // may have jumped to another window, check that the buffer is not in a
   // window.
   if (empty_fnum != 0 && curbuf->b_fnum != empty_fnum) {
-    buf = buflist_findnr(empty_fnum);
+    buf_T *buf = buflist_findnr(empty_fnum);
     if (buf != NULL && buf->b_nwindows == 0) {
       wipe_buffer(buf, true);
     }
@@ -647,9 +645,6 @@ void prepare_help_buffer(void)
 /// highlighting is not used.
 void fix_help_buffer(void)
 {
-  linenr_T lnum;
-  char *line;
-
   // Set filetype to "help".
   if (strcmp(curbuf->b_p_ft, "help") != 0) {
     curbuf->b_ro_locked++;
@@ -659,8 +654,8 @@ void fix_help_buffer(void)
 
   if (!syntax_present(curwin)) {
     bool in_example = false;
-    for (lnum = 1; lnum <= curbuf->b_ml.ml_line_count; lnum++) {
-      line = ml_get_buf(curbuf, lnum);
+    for (linenr_T lnum = 1; lnum <= curbuf->b_ml.ml_line_count; lnum++) {
+      char *line = ml_get_buf(curbuf, lnum);
       const size_t len = strlen(line);
       if (in_example && len > 0 && !ascii_iswhite(line[0])) {
         // End of example: non-white or '<' in first column.
@@ -695,8 +690,8 @@ void fix_help_buffer(void)
           && ASCII_ISALPHA(fname[6])
           && TOLOWER_ASC(fname[7]) == 'x'
           && fname[8] == NUL)) {
-    for (lnum = 1; lnum < curbuf->b_ml.ml_line_count; lnum++) {
-      line = ml_get_buf(curbuf, lnum);
+    for (linenr_T lnum = 1; lnum < curbuf->b_ml.ml_line_count; lnum++) {
+      char *line = ml_get_buf(curbuf, lnum);
       if (strstr(line, "*local-additions*") == NULL) {
         continue;
       }
diff --git a/src/nvim/insexpand.c b/src/nvim/insexpand.c
index 42f3a78f27..bd32c6e2dc 100644
--- a/src/nvim/insexpand.c
+++ b/src/nvim/insexpand.c
@@ -910,7 +910,6 @@ static bool ins_compl_equal(compl_T *match, char *str, size_t len)
 static void ins_compl_longest_match(compl_T *match)
 {
   char *p, *s;
-  int c1, c2;
   int had_match;
 
   if (compl_leader == NULL) {
@@ -936,8 +935,8 @@ static void ins_compl_longest_match(compl_T *match)
   p = compl_leader;
   s = match->cp_str;
   while (*p != NUL) {
-    c1 = utf_ptr2char(p);
-    c2 = utf_ptr2char(s);
+    int c1 = utf_ptr2char(p);
+    int c2 = utf_ptr2char(s);
 
     if ((match->cp_flags & CP_ICASE)
         ? (mb_tolower(c1) != mb_tolower(c2))
@@ -1442,11 +1441,10 @@ static void ins_compl_files(int count, char **files, int thesaurus, int flags, r
 {
   char *ptr;
   int i;
-  FILE *fp;
   int add_r;
 
   for (i = 0; i < count && !got_int && !compl_interrupted; i++) {
-    fp = os_fopen(files[i], "r");  // open dictionary file
+    FILE *fp = os_fopen(files[i], "r");  // open dictionary file
     if (flags != DICT_EXACT && !shortmess(SHM_COMPLETIONSCAN)) {
       msg_hist_off = true;  // reset in msg_trunc()
       vim_snprintf(IObuff, IOSIZE,
@@ -2181,7 +2179,6 @@ bool ins_compl_prep(int c)
 static void ins_compl_fixRedoBufForLeader(char *ptr_arg)
 {
   int len;
-  char *p;
   char *ptr = ptr_arg;
 
   if (ptr == NULL) {
@@ -2192,7 +2189,7 @@ static void ins_compl_fixRedoBufForLeader(char *ptr_arg)
     }
   }
   if (compl_orig_text != NULL) {
-    p = compl_orig_text;
+    char *p = compl_orig_text;
     for (len = 0; p[len] != NUL && p[len] == ptr[len]; len++) {}
     if (len > 0) {
       len -= utf_head_off(p, p + len);
@@ -3853,15 +3850,13 @@ static bool ins_compl_pum_key(int c)
 /// Returns 1 for most keys, height of the popup menu for page-up/down keys.
 static int ins_compl_key2count(int c)
 {
-  int h;
-
   if (c == K_EVENT || c == K_COMMAND || c == K_LUA) {
     int offset = pum_want.item - pum_selected_item;
     return abs(offset);
   }
 
   if (ins_compl_pum_key(c) && c != K_UP && c != K_DOWN) {
-    h = pum_get_height();
+    int h = pum_get_height();
     if (h > 3) {
       h -= 2;       // keep some context
     }
diff --git a/src/nvim/keycodes.c b/src/nvim/keycodes.c
index dcb1b74198..66ee51f09f 100644
--- a/src/nvim/keycodes.c
+++ b/src/nvim/keycodes.c
@@ -469,7 +469,6 @@ char *get_special_key_name(int c, int modifiers)
 
   int i, idx;
   int table_idx;
-  char *s;
 
   string[0] = '<';
   idx = 1;
@@ -536,7 +535,7 @@ char *get_special_key_name(int c, int modifiers)
       } else if (vim_isprintc(c)) {
         string[idx++] = (char)(uint8_t)c;
       } else {
-        s = transchar(c);
+        char *s = transchar(c);
         while (*s) {
           string[idx++] = *s++;
         }
@@ -631,7 +630,6 @@ int find_special_key(const char **const srcp, const size_t src_len, int *const m
   const char *const end = *srcp + src_len - 1;
   const bool in_string = flags & FSK_IN_STRING;
   int modifiers;
-  int bit;
   uvarnumber_T n;
   int l;
 
@@ -686,7 +684,7 @@ int find_special_key(const char **const srcp, const size_t src_len, int *const m
     modifiers = 0x0;
     for (bp = src + 1; bp < last_dash; bp++) {
       if (*bp != '-') {
-        bit = name_to_mod_mask((uint8_t)(*bp));
+        int bit = name_to_mod_mask((uint8_t)(*bp));
         if (bit == 0x0) {
           break;                // Illegal modifier name
         }
diff --git a/src/nvim/main.c b/src/nvim/main.c
index f80fb98918..00eb6e75a5 100644
--- a/src/nvim/main.c
+++ b/src/nvim/main.c
@@ -1749,7 +1749,6 @@ static void create_windows(mparm_T *parmp)
 static void edit_buffers(mparm_T *parmp, char *cwd)
 {
   int arg_idx;                          // index in argument list
-  int i;
   bool advance = true;
   win_T *win;
   char *p_shm_save = NULL;
@@ -1765,7 +1764,7 @@ static void edit_buffers(mparm_T *parmp, char *cwd)
   }
 
   arg_idx = 1;
-  for (i = 1; i < parmp->window_count; i++) {
+  for (int i = 1; i < parmp->window_count; i++) {
     if (cwd != NULL) {
       os_chdir(cwd);
     }
@@ -1869,7 +1868,6 @@ static void exe_pre_commands(mparm_T *parmp)
 {
   char **cmds = parmp->pre_commands;
   int cnt = parmp->n_pre_commands;
-  int i;
 
   if (cnt <= 0) {
     return;
@@ -1878,7 +1876,7 @@ static void exe_pre_commands(mparm_T *parmp)
   curwin->w_cursor.lnum = 0;     // just in case..
   estack_push(ETYPE_ARGS, _("pre-vimrc command line"), 0);
   current_sctx.sc_sid = SID_CMDARG;
-  for (i = 0; i < cnt; i++) {
+  for (int i = 0; i < cnt; i++) {
     do_cmdline_cmd(cmds[i]);
   }
   estack_pop();
@@ -1889,8 +1887,6 @@ static void exe_pre_commands(mparm_T *parmp)
 // Execute "+", "-c" and "-S" arguments.
 static void exe_commands(mparm_T *parmp)
 {
-  int i;
-
   // We start commands on line 0, make "vim +/pat file" match a
   // pattern on line 1.  But don't move the cursor when an autocommand
   // with g`" was used.
@@ -1901,7 +1897,7 @@ static void exe_commands(mparm_T *parmp)
   estack_push(ETYPE_ARGS, "command line", 0);
   current_sctx.sc_sid = SID_CARG;
   current_sctx.sc_seq = 0;
-  for (i = 0; i < parmp->n_commands; i++) {
+  for (int i = 0; i < parmp->n_commands; i++) {
     do_cmdline_cmd(parmp->commands[i]);
     if (parmp->cmds_tofree[i]) {
       xfree(parmp->commands[i]);
diff --git a/src/nvim/match.c b/src/nvim/match.c
index 5ecccdd1dd..3420455e5f 100644
--- a/src/nvim/match.c
+++ b/src/nvim/match.c
@@ -354,11 +354,10 @@ void init_search_hl(win_T *wp, match_T *search_hl)
 static int next_search_hl_pos(match_T *shl, linenr_T lnum, matchitem_T *match, colnr_T mincol)
   FUNC_ATTR_NONNULL_ALL
 {
-  int i;
   int found = -1;
 
   shl->lnum = 0;
-  for (i = match->mit_pos_cur; i < match->mit_pos_count; i++) {
+  for (int i = match->mit_pos_cur; i < match->mit_pos_count; i++) {
     llpos_T *pos = &match->mit_pos_array[i];
 
     if (pos->lnum == 0) {
@@ -902,7 +901,6 @@ void f_clearmatches(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 void f_getmatches(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 {
   matchitem_T *cur;
-  int i;
   win_T *win = get_optional_window(argvars, 0);
 
   tv_list_alloc_ret(rettv, kListLenMayKnow);
@@ -915,7 +913,7 @@ void f_getmatches(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     dict_T *dict = tv_dict_alloc();
     if (cur->mit_match.regprog == NULL) {
       // match added with matchaddpos()
-      for (i = 0; i < cur->mit_pos_count; i++) {
+      for (int i = 0; i < cur->mit_pos_count; i++) {
         llpos_T *llpos;
         char buf[30];  // use 30 to avoid compiler warning
 
diff --git a/src/nvim/mbyte.c b/src/nvim/mbyte.c
index 39ee65d9d3..0d468889a4 100644
--- a/src/nvim/mbyte.c
+++ b/src/nvim/mbyte.c
@@ -693,9 +693,7 @@ static int utf_safe_read_char_adv(const char **s, size_t *n)
 // Note: composing characters are skipped!
 int mb_ptr2char_adv(const char **const pp)
 {
-  int c;
-
-  c = utf_ptr2char(*pp);
+  int c = utf_ptr2char(*pp);
   *pp += utfc_ptr2len(*pp);
   return c;
 }
@@ -704,9 +702,7 @@ int mb_ptr2char_adv(const char **const pp)
 // Note: composing characters are returned as separate characters.
 int mb_cptr2char_adv(const char **pp)
 {
-  int c;
-
-  c = utf_ptr2char(*pp);
+  int c = utf_ptr2char(*pp);
   *pp += utf_ptr2len(*pp);
   return c;
 }
@@ -716,9 +712,7 @@ int mb_cptr2char_adv(const char **pp)
 /// behaves like a composing character.
 bool utf_composinglike(const char *p1, const char *p2)
 {
-  int c2;
-
-  c2 = utf_ptr2char(p2);
+  int c2 = utf_ptr2char(p2);
   if (utf_iscomposing(c2)) {
     return true;
   }
@@ -842,10 +836,9 @@ int utf_byte2len(int b)
 // Never returns zero.
 int utf_ptr2len_len(const char *p, int size)
 {
-  int len;
   int m;
 
-  len = utf8len_tab[(uint8_t)(*p)];
+  int len = utf8len_tab[(uint8_t)(*p)];
   if (len == 1) {
     return 1;           // NUL, ascii or illegal lead byte
   }
@@ -905,9 +898,6 @@ int utfc_ptr2len(const char *const p)
 /// Returns 1 for an illegal char or an incomplete byte sequence.
 int utfc_ptr2len_len(const char *p, int size)
 {
-  int len;
-  int prevlen;
-
   if (size < 1 || *p == NUL) {
     return 0;
   }
@@ -916,7 +906,7 @@ int utfc_ptr2len_len(const char *p, int size)
   }
 
   // Skip over first UTF-8 char, stopping at a NUL byte.
-  len = utf_ptr2len_len(p, size);
+  int len = utf_ptr2len_len(p, size);
 
   // Check for illegal byte and incomplete byte sequence.
   if ((len == 1 && (uint8_t)p[0] >= 0x80) || len > size) {
@@ -925,17 +915,15 @@ int utfc_ptr2len_len(const char *p, int size)
 
   // Check for composing characters.  We can handle only the first six, but
   // skip all of them (otherwise the cursor would get stuck).
-  prevlen = 0;
+  int prevlen = 0;
   while (len < size) {
-    int len_next_char;
-
     if ((uint8_t)p[len] < 0x80) {
       break;
     }
 
     // Next character length should not go beyond size to ensure that
     // utf_composinglike(...) does not read beyond size.
-    len_next_char = utf_ptr2len_len(p + len, size - len);
+    int len_next_char = utf_ptr2len_len(p + len, size - len);
     if (len_next_char > size - len) {
       break;
     }
@@ -1836,7 +1824,6 @@ int utf_cp_tail_off(const char *base, const char *p_in)
 int utf_cp_head_off(const char *base, const char *p)
 {
   int i;
-  int j;
 
   if (*p == NUL) {
     return 0;
@@ -1850,7 +1837,7 @@ int utf_cp_head_off(const char *base, const char *p)
   }
 
   // Find the last character that is 10xx.xxxx
-  for (j = 0; ((uint8_t)p[j + 1] & 0xc0) == 0x80; j++) {}
+  for (int j = 0; ((uint8_t)p[j + 1] & 0xc0) == 0x80; j++) {}
 
   // Check for illegal sequence.
   if (utf8len_tab[(uint8_t)p[i]] == 1) {
@@ -2118,7 +2105,6 @@ char *enc_skip(char *p)
 char *enc_canonize(char *enc)
   FUNC_ATTR_NONNULL_RET
 {
-  char *p, *s;
   if (strcmp(enc, "default") == 0) {
     // Use the default encoding as found by set_init_1().
     return xstrdup(fenc_default);
@@ -2127,8 +2113,8 @@ char *enc_canonize(char *enc)
   // copy "enc" to allocated memory, with room for two '-'
   char *r = xmalloc(strlen(enc) + 3);
   // Make it all lower case and replace '_' with '-'.
-  p = r;
-  for (s = enc; *s != NUL; s++) {
+  char *p = r;
+  for (char *s = enc; *s != NUL; s++) {
     if (*s == '_') {
       *p++ = '-';
     } else {
@@ -2260,17 +2246,14 @@ enc_locale_copy_enc:
 // (should return iconv_t, but that causes problems with prototypes).
 void *my_iconv_open(char *to, char *from)
 {
-  iconv_t fd;
 #define ICONV_TESTLEN 400
   char tobuf[ICONV_TESTLEN];
-  char *p;
-  size_t tolen;
   static WorkingStatus iconv_working = kUnknown;
 
   if (iconv_working == kBroken) {
     return (void *)-1;          // detected a broken iconv() previously
   }
-  fd = iconv_open(enc_skip(to), enc_skip(from));
+  iconv_t fd = iconv_open(enc_skip(to), enc_skip(from));
 
   if (fd != (iconv_t)-1 && iconv_working == kUnknown) {
     // Do a dummy iconv() call to check if it actually works.  There is a
@@ -2278,8 +2261,8 @@ void *my_iconv_open(char *to, char *from)
     // because it's wide-spread.  The symptoms are that after outputting
     // the initial shift state the "to" pointer is NULL and conversion
     // stops for no apparent reason after about 8160 characters.
-    p = tobuf;
-    tolen = ICONV_TESTLEN;
+    char *p = tobuf;
+    size_t tolen = ICONV_TESTLEN;
     (void)iconv(fd, NULL, NULL, &p, &tolen);
     if (p == NULL) {
       iconv_working = kBroken;
@@ -2301,24 +2284,19 @@ void *my_iconv_open(char *to, char *from)
 static char *iconv_string(const vimconv_T *const vcp, const char *str, size_t slen,
                           size_t *unconvlenp, size_t *resultlenp)
 {
-  const char *from;
-  size_t fromlen;
   char *to;
-  size_t tolen;
   size_t len = 0;
   size_t done = 0;
   char *result = NULL;
-  char *p;
-  int l;
 
-  from = str;
-  fromlen = slen;
+  const char *from = str;
+  size_t fromlen = slen;
   while (true) {
     if (len == 0 || ICONV_ERRNO == ICONV_E2BIG) {
       // Allocate enough room for most conversions.  When re-allocating
       // increase the buffer size.
       len = len + fromlen * 2 + 40;
-      p = xmalloc(len);
+      char *p = xmalloc(len);
       if (done > 0) {
         memmove(p, result, done);
       }
@@ -2327,7 +2305,7 @@ static char *iconv_string(const vimconv_T *const vcp, const char *str, size_t sl
     }
 
     to = result + done;
-    tolen = len - done - 2;
+    size_t tolen = len - done - 2;
     // Avoid a warning for systems with a wrong iconv() prototype by
     // casting the second argument to void *.
     if (iconv(vcp->vc_fd, (void *)&from, &fromlen, &to, &tolen) != SIZE_MAX) {
@@ -2357,7 +2335,7 @@ static char *iconv_string(const vimconv_T *const vcp, const char *str, size_t sl
       if (utf_ptr2cells(from) > 1) {
         *to++ = '?';
       }
-      l = utfc_ptr2len_len(from, (int)fromlen);
+      int l = utfc_ptr2len_len(from, (int)fromlen);
       from += l;
       fromlen -= (size_t)l;
     } else if (ICONV_ERRNO != ICONV_E2BIG) {
@@ -2421,8 +2399,6 @@ int convert_setup(vimconv_T *vcp, char *from, char *to)
 int convert_setup_ext(vimconv_T *vcp, char *from, bool from_unicode_is_utf8, char *to,
                       bool to_unicode_is_utf8)
 {
-  int from_prop;
-  int to_prop;
   int from_is_utf8;
   int to_is_utf8;
 
@@ -2438,8 +2414,8 @@ int convert_setup_ext(vimconv_T *vcp, char *from, bool from_unicode_is_utf8, cha
     return OK;
   }
 
-  from_prop = enc_canon_props(from);
-  to_prop = enc_canon_props(to);
+  int from_prop = enc_canon_props(from);
+  int to_prop = enc_canon_props(to);
   if (from_unicode_is_utf8) {
     from_is_utf8 = from_prop & ENC_UNICODE;
   } else {
diff --git a/src/nvim/menu.c b/src/nvim/menu.c
index 0e6b91090a..9e3fd56c36 100644
--- a/src/nvim/menu.c
+++ b/src/nvim/menu.c
@@ -800,8 +800,6 @@ static int show_menus(char *const path_name, int modes)
 /// Recursively show the mappings associated with the menus under the given one
 static void show_menus_recursive(vimmenu_T *menu, int modes, int depth)
 {
-  int i;
-
   if (menu != NULL && (menu->modes & modes) == 0x0) {
     return;
   }
@@ -811,7 +809,7 @@ static void show_menus_recursive(vimmenu_T *menu, int modes, int depth)
     if (got_int) {              // "q" hit for "--more--"
       return;
     }
-    for (i = 0; i < depth; i++) {
+    for (int i = 0; i < depth; i++) {
       msg_puts("  ");
     }
     if (menu->priority) {
@@ -829,7 +827,7 @@ static void show_menus_recursive(vimmenu_T *menu, int modes, int depth)
         if (got_int) {                  // "q" hit for "--more--"
           return;
         }
-        for (i = 0; i < depth + 2; i++) {
+        for (int i = 0; i < depth + 2; i++) {
           msg_puts("  ");
         }
         msg_puts(menu_mode_chars[bit]);
diff --git a/src/nvim/message.c b/src/nvim/message.c
index dbef962551..8be8581537 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -2680,7 +2680,6 @@ static int do_more_prompt(int typed_char)
   bool to_redraw = false;
   msgchunk_T *mp_last = NULL;
   msgchunk_T *mp;
-  int i;
 
   // If headless mode is enabled and no input is required, this variable
   // will be true. However If server mode is enabled, the message "--more--"
@@ -2698,7 +2697,7 @@ static int do_more_prompt(int typed_char)
   if (typed_char == 'G') {
     // "g<": Find first line on the last page.
     mp_last = msg_sb_start(last_msgchunk);
-    for (i = 0; i < Rows - 2 && mp_last != NULL
+    for (int i = 0; i < Rows - 2 && mp_last != NULL
          && mp_last->sb_prev != NULL; i++) {
       mp_last = msg_sb_start(mp_last->sb_prev);
     }
@@ -2816,13 +2815,13 @@ static int do_more_prompt(int typed_char)
         }
 
         // go to start of line at top of the screen
-        for (i = 0; i < Rows - 2 && mp != NULL && mp->sb_prev != NULL; i++) {
+        for (int i = 0; i < Rows - 2 && mp != NULL && mp->sb_prev != NULL; i++) {
           mp = msg_sb_start(mp->sb_prev);
         }
 
         if (mp != NULL && (mp->sb_prev != NULL || to_redraw)) {
           // Find line to be displayed at top
-          for (i = 0; i > toscroll; i--) {
+          for (int i = 0; i > toscroll; i--) {
             if (mp == NULL || mp->sb_prev == NULL) {
               break;
             }
@@ -2846,7 +2845,7 @@ static int do_more_prompt(int typed_char)
             // event fragmentization, not unnecessary scroll events).
             grid_fill(&msg_grid_adj, 0, Rows, 0, Columns, ' ', ' ',
                       HL_ATTR(HLF_MSG));
-            for (i = 0; mp != NULL && i < Rows - 1; i++) {
+            for (int i = 0; mp != NULL && i < Rows - 1; i++) {
               mp = disp_sb_line(i, mp);
               msg_scrolled++;
             }
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index db59c2c98e..9c2b4e7b74 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -2541,9 +2541,7 @@ int op_change(oparg_T *oap)
 #if defined(EXITFREE)
 void clear_registers(void)
 {
-  int i;
-
-  for (i = 0; i < NUM_REGISTERS; i++) {
+  for (int i = 0; i < NUM_REGISTERS; i++) {
     free_register(&y_regs[i]);
   }
 }
diff --git a/src/nvim/os/shell.c b/src/nvim/os/shell.c
index b3ce4a3c91..2fd4c732fc 100644
--- a/src/nvim/os/shell.c
+++ b/src/nvim/os/shell.c
@@ -1234,12 +1234,12 @@ static size_t word_length(const char *str)
 /// before we finish writing.
 static void read_input(DynamicBuffer *buf)
 {
-  size_t written = 0, l = 0, len = 0;
+  size_t written = 0, len = 0;
   linenr_T lnum = curbuf->b_op_start.lnum;
   char *lp = ml_get(lnum);
 
   while (true) {
-    l = strlen(lp + written);
+    size_t l = strlen(lp + written);
     if (l == 0) {
       len = 0;
     } else if (lp[written] == NL) {
diff --git a/src/nvim/path.c b/src/nvim/path.c
index d08866ed14..dc7e0d9645 100644
--- a/src/nvim/path.c
+++ b/src/nvim/path.c
@@ -1554,14 +1554,13 @@ void simplify_filename(char *filename)
 
       if (components > 0) {             // strip one preceding component
         bool do_strip = false;
-        char saved_char;
 
         // Don't strip for an erroneous file name.
         if (!stripping_disabled) {
           // If the preceding component does not exist in the file
           // system, we strip it.  On Unix, we don't accept a symbolic
           // link that refers to a non-existent file.
-          saved_char = p[-1];
+          char saved_char = p[-1];
           p[-1] = NUL;
           FileInfo file_info;
           if (!os_fileinfo_link(filename, &file_info)) {
@@ -2186,12 +2185,7 @@ int expand_wildcards_eval(char **pat, int *num_file, char ***file, int flags)
 ///                      NULL or points to "".
 int expand_wildcards(int num_pat, char **pat, int *num_files, char ***files, int flags)
 {
-  int retval;
-  int i, j;
-  char *p;
-  int non_suf_match;            // number without matching suffix
-
-  retval = gen_expand_wildcards(num_pat, pat, num_files, files, flags);
+  int retval = gen_expand_wildcards(num_pat, pat, num_files, files, flags);
 
   // When keeping all matches, return here
   if ((flags & EW_KEEPALL) || retval == FAIL) {
@@ -2200,18 +2194,16 @@ int expand_wildcards(int num_pat, char **pat, int *num_files, char ***files, int
 
   // Remove names that match 'wildignore'.
   if (*p_wig) {
-    char *ffname;
-
     // check all files in (*files)[]
     assert(*num_files == 0 || *files != NULL);
-    for (i = 0; i < *num_files; i++) {
-      ffname = FullName_save((*files)[i], false);
+    for (int i = 0; i < *num_files; i++) {
+      char *ffname = FullName_save((*files)[i], false);
       assert((*files)[i] != NULL);
       assert(ffname != NULL);
       if (match_file_list(p_wig, (*files)[i], ffname)) {
         // remove this matching file from the list
         xfree((*files)[i]);
-        for (j = i; j + 1 < *num_files; j++) {
+        for (int j = i; j + 1 < *num_files; j++) {
           (*files)[j] = (*files)[j + 1];
         }
         (*num_files)--;
@@ -2225,12 +2217,12 @@ int expand_wildcards(int num_pat, char **pat, int *num_files, char ***files, int
   // Skip when interrupted, the result probably won't be used.
   assert(*num_files == 0 || *files != NULL);
   if (*num_files > 1 && !got_int) {
-    non_suf_match = 0;
-    for (i = 0; i < *num_files; i++) {
+    int non_suf_match = 0;            // number without matching suffix
+    for (int i = 0; i < *num_files; i++) {
       if (!match_suffix((*files)[i])) {
         // Move the name without matching suffix to the front of the list.
-        p = (*files)[i];
-        for (j = i; j > non_suf_match; j--) {
+        char *p = (*files)[i];
+        for (int j = i; j > non_suf_match; j--) {
           (*files)[j] = (*files)[j - 1];
         }
         (*files)[non_suf_match++] = p;
diff --git a/src/nvim/popupmenu.c b/src/nvim/popupmenu.c
index 7db8fe01b7..4ed5d64c60 100644
--- a/src/nvim/popupmenu.c
+++ b/src/nvim/popupmenu.c
@@ -420,7 +420,6 @@ void pum_redraw(void)
   int row = 0;
   int attr_scroll = win_hl_attr(curwin, HLF_PSB);
   int attr_thumb = win_hl_attr(curwin, HLF_PST);
-  int i;
   char *s;
   char *p = NULL;
   int width;
@@ -499,7 +498,7 @@ void pum_redraw(void)
                 / (pum_size - pum_height);
   }
 
-  for (i = 0; i < pum_height; i++) {
+  for (int i = 0; i < pum_height; i++) {
     int idx = i + pum_first;
     const int *const attrs = (idx == pum_selected) ? attrsSel : attrsNorm;
     int attr = attrs[0];  // start with "word" highlight
diff --git a/src/nvim/profile.c b/src/nvim/profile.c
index 3e824fc34f..80f613c096 100644
--- a/src/nvim/profile.c
+++ b/src/nvim/profile.c
@@ -434,12 +434,11 @@ static void prof_func_line(FILE *fd, int count, const proftime_T *total, const p
 /// @param prefer_self  when equal print only self time
 static void prof_sort_list(FILE *fd, ufunc_T **sorttab, int st_len, char *title, bool prefer_self)
 {
-  int i;
   ufunc_T *fp;
 
   fprintf(fd, "FUNCTIONS SORTED ON %s TIME\n", title);
   fprintf(fd, "count  total (s)   self (s)  function\n");
-  for (i = 0; i < 20 && i < st_len; i++) {
+  for (int i = 0; i < 20 && i < st_len; i++) {
     fp = sorttab[i];
     prof_func_line(fd, fp->uf_tm_count, &fp->uf_tm_total, &fp->uf_tm_self,
                    prefer_self);
diff --git a/src/nvim/runtime.c b/src/nvim/runtime.c
index 1438385e66..83c4a68af2 100644
--- a/src/nvim/runtime.c
+++ b/src/nvim/runtime.c
@@ -2583,10 +2583,8 @@ char *getsourceline(int c, void *cookie, int indent, bool do_concat)
   }
 
   if (line != NULL && sp->conv.vc_type != CONV_NONE) {
-    char *s;
-
     // Convert the encoding of the script line.
-    s = string_convert(&sp->conv, line, NULL);
+    char *s = string_convert(&sp->conv, line, NULL);
     if (s != NULL) {
       xfree(line);
       line = s;
diff --git a/src/nvim/spellfile.c b/src/nvim/spellfile.c
index 9bf5ef3ed8..67b29e25a4 100644
--- a/src/nvim/spellfile.c
+++ b/src/nvim/spellfile.c
@@ -3395,7 +3395,7 @@ static int store_aff_word(spellinfo_T *spin, char *word, char *afflist, afffile_
   affentry_T *ae;
   char newword[MAXWLEN];
   int retval = OK;
-  int i, j;
+  int j;
   char *p;
   int use_flags;
   char *use_pfxlist;
@@ -3452,7 +3452,7 @@ static int store_aff_word(spellinfo_T *spin, char *word, char *afflist, afffile_
               p = word;
               if (ae->ae_chop != NULL) {
                 // Skip chop string.
-                i = mb_charlen(ae->ae_chop);
+                int i = mb_charlen(ae->ae_chop);
                 for (; i > 0; i--) {
                   MB_PTR_ADV(p);
                 }
@@ -3464,7 +3464,7 @@ static int store_aff_word(spellinfo_T *spin, char *word, char *afflist, afffile_
               if (ae->ae_chop != NULL) {
                 // Remove chop string.
                 p = newword + strlen(newword);
-                i = mb_charlen(ae->ae_chop);
+                int i = mb_charlen(ae->ae_chop);
                 for (; i > 0; i--) {
                   MB_PTR_BACK(newword, p);
                 }
@@ -3514,7 +3514,7 @@ static int store_aff_word(spellinfo_T *spin, char *word, char *afflist, afffile_
 
                 // Combine the prefix IDs. Avoid adding the
                 // same ID twice.
-                for (i = 0; i < pfxlen; i++) {
+                for (int i = 0; i < pfxlen; i++) {
                   for (j = 0; j < use_pfxlen; j++) {
                     if (pfxlist[i] == use_pfxlist[j]) {
                       break;
@@ -3536,7 +3536,7 @@ static int store_aff_word(spellinfo_T *spin, char *word, char *afflist, afffile_
                 // Combine the list of compound flags.
                 // Concatenate them to the prefix IDs list.
                 // Avoid adding the same ID twice.
-                for (i = pfxlen; pfxlist[i] != NUL; i++) {
+                for (int i = pfxlen; pfxlist[i] != NUL; i++) {
                   for (j = use_pfxlen; use_pfxlist[j] != NUL; j++) {
                     if (pfxlist[i] == use_pfxlist[j]) {
                       break;
@@ -5072,16 +5072,15 @@ static int sug_maketable(spellinfo_T *spin)
 /// @param gap  place to store line of numbers
 static int sug_filltable(spellinfo_T *spin, wordnode_T *node, int startwordnr, garray_T *gap)
 {
-  wordnode_T *p, *np;
   int wordnr = startwordnr;
   int nr;
   int prev_nr;
 
-  for (p = node; p != NULL; p = p->wn_sibling) {
+  for (wordnode_T *p = node; p != NULL; p = p->wn_sibling) {
     if (p->wn_byte == NUL) {
       gap->ga_len = 0;
       prev_nr = 0;
-      for (np = p; np != NULL && np->wn_byte == NUL; np = np->wn_sibling) {
+      for (wordnode_T *np = p; np != NULL && np->wn_byte == NUL; np = np->wn_sibling) {
         ga_grow(gap, 10);
 
         nr = (np->wn_flags << 16) + (np->wn_region & 0xffff);
@@ -5810,7 +5809,6 @@ static int write_spell_prefcond(FILE *fd, garray_T *gap, size_t *fwv)
 // Use map string "map" for languages "lp".
 static void set_map_str(slang_T *lp, const char *map)
 {
-  const char *p;
   int headc = 0;
 
   if (*map == NUL) {
@@ -5828,7 +5826,7 @@ static void set_map_str(slang_T *lp, const char *map)
   // The similar characters are stored separated with slashes:
   // "aaa/bbb/ccc/".  Fill sl_map_array[c] with the character before c and
   // before the same slash.  For characters above 255 sl_map_hash is used.
-  for (p = map; *p != NUL;) {
+  for (const char *p = map; *p != NUL;) {
     int c = mb_cptr2char_adv(&p);
     if (c == '/') {
       headc = 0;
diff --git a/src/nvim/strings.c b/src/nvim/strings.c
index 007d088bbb..eb851a4c1b 100644
--- a/src/nvim/strings.c
+++ b/src/nvim/strings.c
@@ -485,10 +485,8 @@ void sort_strings(char **files, int count)
 bool has_non_ascii(const char *s)
   FUNC_ATTR_PURE
 {
-  const char *p;
-
   if (s != NULL) {
-    for (p = s; *p != NUL; p++) {
+    for (const char *p = s; *p != NUL; p++) {
       if ((uint8_t)(*p) >= 128) {
         return true;
       }
@@ -1964,7 +1962,6 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
           assert(str_arg_l < sizeof(tmp));
 
           if (remove_trailing_zeroes) {
-            int i;
             char *tp;
 
             // using %g or %G: remove superfluous zeroes
@@ -1979,7 +1976,7 @@ int vim_vsnprintf_typval(char *str, size_t str_m, const char *fmt, va_list ap_st
                   STRMOVE(tp + 1, tp + 2);
                   str_arg_l--;
                 }
-                i = (tp[1] == '-') ? 2 : 1;
+                int i = (tp[1] == '-') ? 2 : 1;
                 while (tp[i] == '0') {
                   // change "1.0e07" to "1.0e7"
                   STRMOVE(tp + i, tp + i + 1);
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index 67d762d546..d83d58229f 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -307,7 +307,6 @@ void syn_set_timeout(proftime_T *tm)
 // window.
 void syntax_start(win_T *wp, linenr_T lnum)
 {
-  synstate_T *p;
   synstate_T *last_valid = NULL;
   synstate_T *last_min_valid = NULL;
   synstate_T *sp, *prev = NULL;
@@ -362,7 +361,7 @@ void syntax_start(win_T *wp, linenr_T lnum)
   // Only do this if lnum is not before and not to far beyond a saved state.
   if (INVALID_STATE(&current_state) && syn_block->b_sst_array != NULL) {
     // Find last valid saved state before start_lnum.
-    for (p = syn_block->b_sst_first; p != NULL; p = p->sst_next) {
+    for (synstate_T *p = syn_block->b_sst_first; p != NULL; p = p->sst_next) {
       if (p->sst_lnum > lnum) {
         break;
       }
@@ -877,13 +876,11 @@ static void syn_update_ends(bool startofline)
 
 static void syn_stack_free_block(synblock_T *block)
 {
-  synstate_T *p;
-
   if (block->b_sst_array == NULL) {
     return;
   }
 
-  for (p = block->b_sst_first; p != NULL; p = p->sst_next) {
+  for (synstate_T *p = block->b_sst_first; p != NULL; p = p->sst_next) {
     clear_syn_state(p);
   }
   XFREE_CLEAR(block->b_sst_array);
@@ -1037,7 +1034,7 @@ static void syn_stack_apply_changes_block(synblock_T *block, buf_T *buf)
 /// @return  true if at least one entry was freed.
 static bool syn_stack_cleanup(void)
 {
-  synstate_T *p, *prev;
+  synstate_T *prev;
   disptick_T tick;
   int dist;
   bool retval = false;
@@ -1059,7 +1056,7 @@ static bool syn_stack_cleanup(void)
   tick = syn_block->b_sst_lasttick;
   bool above = false;
   prev = syn_block->b_sst_first;
-  for (p = prev->sst_next; p != NULL; prev = p, p = p->sst_next) {
+  for (synstate_T *p = prev->sst_next; p != NULL; prev = p, p = p->sst_next) {
     if (prev->sst_lnum + dist > p->sst_lnum) {
       if (p->sst_tick > syn_block->b_sst_lasttick) {
         if (!above || p->sst_tick < tick) {
@@ -1075,7 +1072,7 @@ static bool syn_stack_cleanup(void)
   // Go through the list to make the entries for the oldest tick at an
   // interval of several lines.
   prev = syn_block->b_sst_first;
-  for (p = prev->sst_next; p != NULL; prev = p, p = p->sst_next) {
+  for (synstate_T *p = prev->sst_next; p != NULL; prev = p, p = p->sst_next) {
     if (p->sst_tick == tick && prev->sst_lnum + dist > p->sst_lnum) {
       // Move this entry from used list to free list
       prev->sst_next = p->sst_next;
@@ -1101,10 +1098,8 @@ static void syn_stack_free_entry(synblock_T *block, synstate_T *p)
 // Returns NULL when there is no entry or the first entry is after "lnum".
 static synstate_T *syn_stack_find_entry(linenr_T lnum)
 {
-  synstate_T *p, *prev;
-
-  prev = NULL;
-  for (p = syn_block->b_sst_first; p != NULL; prev = p, p = p->sst_next) {
+  synstate_T *prev = NULL;
+  for (synstate_T *p = syn_block->b_sst_first; p != NULL; prev = p, p = p->sst_next) {
     if (p->sst_lnum == lnum) {
       return p;
     }
diff --git a/src/nvim/textformat.c b/src/nvim/textformat.c
index ca57bf3259..58037fef36 100644
--- a/src/nvim/textformat.c
+++ b/src/nvim/textformat.c
@@ -101,7 +101,6 @@ void internal_format(int textwidth, int second_indent, int flags, bool format_on
     int wantcol;                        // column at textwidth border
     int foundcol;                       // column for start of spaces
     int end_foundcol = 0;               // column for start of word
-    colnr_T len;
     colnr_T virtcol;
     int orig_col = 0;
     char *saved_text = NULL;
@@ -437,7 +436,7 @@ void internal_format(int textwidth, int second_indent, int flags, bool format_on
       // Check if cursor is not past the NUL off the line, cindent
       // may have added or removed indent.
       curwin->w_cursor.col += startcol;
-      len = (colnr_T)strlen(get_cursor_line_ptr());
+      colnr_T len = (colnr_T)strlen(get_cursor_line_ptr());
       if (curwin->w_cursor.col > len) {
         curwin->w_cursor.col = len;
       }
@@ -518,7 +517,6 @@ static bool same_leader(linenr_T lnum, int leader1_len, char *leader1_flags, int
                         char *leader2_flags)
 {
   int idx1 = 0, idx2 = 0;
-  char *p;
   char *line1;
   char *line2;
 
@@ -532,7 +530,7 @@ static bool same_leader(linenr_T lnum, int leader1_len, char *leader1_flags, int
   // If first leader has 's' flag, the lines can only be joined if there is
   // some text after it and the second line has the 'm' flag.
   if (leader1_flags != NULL) {
-    for (p = leader1_flags; *p && *p != ':'; p++) {
+    for (char *p = leader1_flags; *p && *p != ':'; p++) {
       if (*p == COM_FIRST) {
         return leader2_len == 0;
       }
@@ -629,9 +627,7 @@ static bool paragraph_start(linenr_T lnum)
 /// @param prev_line   may start in previous line
 void auto_format(bool trailblank, bool prev_line)
 {
-  colnr_T len;
-  char *linep, *plinep;
-  int cc;
+  char *linep;
 
   if (!has_format_option(FO_AUTO)) {
     return;
@@ -651,7 +647,7 @@ void auto_format(bool trailblank, bool prev_line)
   int wasatend = (pos.col == (colnr_T)strlen(old));
   if (*old != NUL && !trailblank && wasatend) {
     dec_cursor();
-    cc = gchar_cursor();
+    int cc = gchar_cursor();
     if (!WHITECHAR(cc) && curwin->w_cursor.col > 0
         && has_format_option(FO_ONE_LETTER)) {
       dec_cursor();
@@ -702,9 +698,9 @@ void auto_format(bool trailblank, bool prev_line)
   // formatted.
   if (!wasatend && has_format_option(FO_WHITE_PAR)) {
     linep = get_cursor_line_ptr();
-    len = (colnr_T)strlen(linep);
+    colnr_T len = (colnr_T)strlen(linep);
     if (curwin->w_cursor.col == len) {
-      plinep = xstrnsave(linep, (size_t)len + 2);
+      char *plinep = xstrnsave(linep, (size_t)len + 2);
       plinep[len] = ' ';
       plinep[len + 1] = NUL;
       ml_replace(curwin->w_cursor.lnum, plinep, false);
diff --git a/src/nvim/ugrid.c b/src/nvim/ugrid.c
index 3a422ff2f2..f02b9626cd 100644
--- a/src/nvim/ugrid.c
+++ b/src/nvim/ugrid.c
@@ -61,10 +61,8 @@ void ugrid_scroll(UGrid *grid, int top, int bot, int left, int right, int count)
     step = -1;
   }
 
-  int i;
-
   // Copy cell data
-  for (i = start; i != stop; i += step) {
+  for (int i = start; i != stop; i += step) {
     UCell *target_row = grid->cells[i] + left;
     UCell *source_row = grid->cells[i + count] + left;
     assert(right >= left && left >= 0);
diff --git a/src/nvim/version.c b/src/nvim/version.c
index d36d6a7346..abcb9d94d2 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -2837,7 +2837,6 @@ void intro_message(int colon)
 
 static void do_intro_line(int row, char *mesg, int attr)
 {
-  char *p;
   int l;
 
   // Center the message horizontally.
@@ -2851,7 +2850,7 @@ static void do_intro_line(int row, char *mesg, int attr)
 
   grid_line_start(&default_grid, row);
   // Split up in parts to highlight <> items differently.
-  for (p = mesg; *p != NUL; p += l) {
+  for (char *p = mesg; *p != NUL; p += l) {
     for (l = 0;
          p[l] != NUL && (l == 0 || (p[l] != '<' && p[l - 1] != '>'));
          l++) {