refactor: replace char_u with char

Work on https://github.com/neovim/neovim/issues/459

48 files changed, 504 insertions, 523 deletions

diff --git a/src/nvim/api/buffer.c b/src/nvim/api/buffer.c
index 43027473a0..199650fc55 100644
--- a/src/nvim/api/buffer.c
+++ b/src/nvim/api/buffer.c
@@ -1031,7 +1031,7 @@ String nvim_buf_get_name(Buffer buffer, Arena *arena, Error *err)
     return rv;
   }
 
-  return cstr_as_string((char *)buf->b_ffname);
+  return cstr_as_string(buf->b_ffname);
 }
 
 /// Sets the full file name for a buffer
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 2fa0277df7..ca98aeb34a 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -2044,7 +2044,7 @@ Array nvim_get_mark(String name, Dictionary opts, Error *err)
   // Marks are from an open buffer it fnum is non zero
   if (mark->fmark.fnum != 0) {
     bufnr = mark->fmark.fnum;
-    filename = (char *)buflist_nr2name(bufnr, true, true);
+    filename = buflist_nr2name(bufnr, true, true);
     allocated = true;
     // Marks comes from shada
   } else {
@@ -2232,7 +2232,7 @@ Dictionary nvim_eval_statusline(String str, Dict(eval_statusline) *opts, Error *
 
     // If first character doesn't have a defined highlight,
     // add the default highlight at the beginning of the highlight list
-    if (hltab->start == NULL || ((char *)hltab->start - buf) != 0) {
+    if (hltab->start == NULL || (hltab->start - buf) != 0) {
       Dictionary hl_info = ARRAY_DICT_INIT;
       grpname = get_default_stl_hl(wp, use_winbar);
 
diff --git a/src/nvim/arglist.c b/src/nvim/arglist.c
index 4f940f2fa5..21aa5afbae 100644
--- a/src/nvim/arglist.c
+++ b/src/nvim/arglist.c
@@ -157,7 +157,7 @@ void alist_add(alist_T *al, char *fname, int set_fnum)
 #ifdef BACKSLASH_IN_FILENAME
   slash_adjust(fname);
 #endif
-  AARGLIST(al)[al->al_ga.ga_len].ae_fname = (char_u *)fname;
+  AARGLIST(al)[al->al_ga.ga_len].ae_fname = fname;
   if (set_fnum > 0) {
     AARGLIST(al)[al->al_ga.ga_len].ae_fnum =
       buflist_add(fname, BLN_LISTED | (set_fnum == 2 ? BLN_CURBUF : 0));
@@ -226,7 +226,7 @@ static char *do_one_arg(char *str)
 /// growarray "gap".
 static void get_arglist(garray_T *gap, char *str, int escaped)
 {
-  ga_init(gap, (int)sizeof(char_u *), 20);
+  ga_init(gap, (int)sizeof(char *), 20);
   while (*str != NUL) {
     GA_APPEND(char *, gap, str);
 
@@ -244,12 +244,12 @@ static void get_arglist(garray_T *gap, char *str, int escaped)
 /// "fnames[fcountp]".  When "wig" is true, removes files matching 'wildignore'.
 ///
 /// @return  FAIL or OK.
-int get_arglist_exp(char_u *str, int *fcountp, char ***fnamesp, bool wig)
+int get_arglist_exp(char *str, int *fcountp, char ***fnamesp, bool wig)
 {
   garray_T ga;
   int i;
 
-  get_arglist(&ga, (char *)str, true);
+  get_arglist(&ga, str, true);
 
   if (wig) {
     i = expand_wildcards(ga.ga_len, ga.ga_data,
@@ -297,7 +297,7 @@ static void alist_add_list(int count, char **files, int after, bool will_edit)
     }
     for (int i = 0; i < count; i++) {
       const int flags = BLN_LISTED | (will_edit ? BLN_CURBUF : 0);
-      ARGLIST[after + i].ae_fname = (char_u *)files[i];
+      ARGLIST[after + i].ae_fname = files[i];
       ARGLIST[after + i].ae_fnum = buflist_add(files[i], flags);
     }
     ALIST(curwin)->al_ga.ga_len += count;
@@ -377,7 +377,7 @@ static int do_arglist(char *str, int what, int after, bool will_edit)
       vim_regfree(regmatch.regprog);
       xfree(p);
       if (!didone) {
-        semsg(_(e_nomatch2), ((char_u **)new_ga.ga_data)[i]);
+        semsg(_(e_nomatch2), ((char **)new_ga.ga_data)[i]);
       }
     }
     ga_clear(&new_ga);
@@ -472,7 +472,7 @@ void ex_args(exarg_T *eap)
   } else if (eap->cmdidx == CMD_args) {
     // ":args": list arguments.
     if (ARGCOUNT > 0) {
-      char **items = xmalloc(sizeof(char_u *) * (size_t)ARGCOUNT);
+      char **items = xmalloc(sizeof(char *) * (size_t)ARGCOUNT);
       // Overwrite the command, for a short list there is no scrolling
       // required and no wait_return().
       gotocmdline(true);
@@ -489,10 +489,8 @@ void ex_args(exarg_T *eap)
     ga_grow(gap, GARGCOUNT);
     for (int i = 0; i < GARGCOUNT; i++) {
       if (GARGLIST[i].ae_fname != NULL) {
-        AARGLIST(curwin->w_alist)[gap->ga_len].ae_fname =
-          vim_strsave(GARGLIST[i].ae_fname);
-        AARGLIST(curwin->w_alist)[gap->ga_len].ae_fnum =
-          GARGLIST[i].ae_fnum;
+        AARGLIST(curwin->w_alist)[gap->ga_len].ae_fname = xstrdup(GARGLIST[i].ae_fname);
+        AARGLIST(curwin->w_alist)[gap->ga_len].ae_fnum = GARGLIST[i].ae_fnum;
         gap->ga_len++;
       }
     }
@@ -742,7 +740,7 @@ char *alist_name(aentry_T *aep)
   // Use the name from the associated buffer if it exists.
   bp = buflist_findnr(aep->ae_fnum);
   if (bp == NULL || bp->b_fname == NULL) {
-    return (char *)aep->ae_fname;
+    return aep->ae_fname;
   }
   return bp->b_fname;
 }
diff --git a/src/nvim/autocmd.c b/src/nvim/autocmd.c
index 50e873dc55..e970387456 100644
--- a/src/nvim/autocmd.c
+++ b/src/nvim/autocmd.c
@@ -1720,9 +1720,9 @@ bool apply_autocmds_group(event_T event, char *fname, char *fname_io, bool force
       fname = NULL;
     } else {
       if (event == EVENT_SYNTAX) {
-        fname = (char *)buf->b_p_syn;
+        fname = buf->b_p_syn;
       } else if (event == EVENT_FILETYPE) {
-        fname = (char *)buf->b_p_ft;
+        fname = buf->b_p_ft;
       } else {
         if (buf->b_sfname != NULL) {
           sfname = xstrdup(buf->b_sfname);
diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index c56fd9e6a8..d7d680b0fd 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -116,11 +116,11 @@ typedef uint64_t disptick_T;  // display tick type
  * The taggy struct is used to store the information about a :tag command.
  */
 typedef struct taggy {
-  char_u *tagname;         // tag name
+  char *tagname;                // tag name
   fmark_T fmark;                // cursor position BEFORE ":tag"
   int cur_match;                // match number
   int cur_fnum;                 // buffer number used for cur_match
-  char_u *user_data;            // used with tagfunc
+  char *user_data;              // used with tagfunc
 } taggy_T;
 
 typedef struct buffblock buffblock_T;
@@ -131,7 +131,7 @@ typedef struct buffheader buffheader_T;
  */
 struct buffblock {
   buffblock_T *b_next;  // pointer to next buffblock
-  char_u b_str[1];      // contents (actually longer)
+  char b_str[1];        // contents (actually longer)
 };
 
 /*
@@ -159,39 +159,39 @@ typedef struct {
 #define w_p_arab w_onebuf_opt.wo_arab  // 'arabic'
   int wo_bri;
 #define w_p_bri w_onebuf_opt.wo_bri    // 'breakindent'
-  char_u *wo_briopt;
+  char *wo_briopt;
 #define w_p_briopt w_onebuf_opt.wo_briopt  // 'breakindentopt'
   int wo_diff;
 #define w_p_diff w_onebuf_opt.wo_diff  // 'diff'
-  char_u *wo_fdc;
+  char *wo_fdc;
 #define w_p_fdc w_onebuf_opt.wo_fdc    // 'foldcolumn'
-  char_u *wo_fdc_save;
+  char *wo_fdc_save;
 #define w_p_fdc_save w_onebuf_opt.wo_fdc_save  // 'fdc' saved for diff mode
   int wo_fen;
 #define w_p_fen w_onebuf_opt.wo_fen    // 'foldenable'
   int wo_fen_save;
   // 'foldenable' saved for diff mode
 #define w_p_fen_save w_onebuf_opt.wo_fen_save
-  char_u *wo_fdi;
+  char *wo_fdi;
 #define w_p_fdi w_onebuf_opt.wo_fdi    // 'foldignore'
   long wo_fdl;
 #define w_p_fdl w_onebuf_opt.wo_fdl    // 'foldlevel'
   long wo_fdl_save;
   // 'foldlevel' state saved for diff mode
 #define w_p_fdl_save w_onebuf_opt.wo_fdl_save
-  char_u *wo_fdm;
+  char *wo_fdm;
 #define w_p_fdm w_onebuf_opt.wo_fdm    // 'foldmethod'
-  char_u *wo_fdm_save;
+  char *wo_fdm_save;
 #define w_p_fdm_save w_onebuf_opt.wo_fdm_save  // 'fdm' saved for diff mode
   long wo_fml;
 #define w_p_fml w_onebuf_opt.wo_fml    // 'foldminlines'
   long wo_fdn;
 #define w_p_fdn w_onebuf_opt.wo_fdn    // 'foldnestmax'
-  char_u *wo_fde;
+  char *wo_fde;
 #define w_p_fde w_onebuf_opt.wo_fde    // 'foldexpr'
-  char_u *wo_fdt;
+  char *wo_fdt;
 #define w_p_fdt w_onebuf_opt.wo_fdt   // 'foldtext'
-  char_u *wo_fmr;
+  char *wo_fmr;
 #define w_p_fmr w_onebuf_opt.wo_fmr    // 'foldmarker'
   int wo_lbr;
 #define w_p_lbr w_onebuf_opt.wo_lbr    // 'linebreak'
@@ -201,7 +201,7 @@ typedef struct {
 #define w_p_nu w_onebuf_opt.wo_nu       // 'number'
   int wo_rnu;
 #define w_p_rnu w_onebuf_opt.wo_rnu     // 'relativenumber'
-  char_u *wo_ve;
+  char *wo_ve;
 #define w_p_ve w_onebuf_opt.wo_ve       // 'virtualedit'
   unsigned wo_ve_flags;
 #define w_ve_flags w_onebuf_opt.wo_ve_flags  // flags for 'virtualedit'
@@ -215,7 +215,7 @@ typedef struct {
 #define w_p_pvw w_onebuf_opt.wo_pvw    // 'previewwindow'
   int wo_rl;
 #define w_p_rl w_onebuf_opt.wo_rl      // 'rightleft'
-  char_u *wo_rlc;
+  char *wo_rlc;
 #define w_p_rlc w_onebuf_opt.wo_rlc    // 'rightleftcmd'
   long wo_scr;
 #define w_p_scr w_onebuf_opt.wo_scr     // 'scroll'
@@ -225,13 +225,13 @@ typedef struct {
 #define w_p_cuc w_onebuf_opt.wo_cuc    // 'cursorcolumn'
   int wo_cul;
 #define w_p_cul w_onebuf_opt.wo_cul    // 'cursorline'
-  char_u *wo_culopt;
+  char *wo_culopt;
 #define w_p_culopt w_onebuf_opt.wo_culopt  // 'cursorlineopt'
-  char_u *wo_cc;
+  char *wo_cc;
 #define w_p_cc w_onebuf_opt.wo_cc      // 'colorcolumn'
-  char_u *wo_sbr;
+  char *wo_sbr;
 #define w_p_sbr w_onebuf_opt.wo_sbr    // 'showbreak'
-  char_u *wo_stl;
+  char *wo_stl;
 #define w_p_stl w_onebuf_opt.wo_stl     // 'statusline'
   char *wo_wbr;
 #define w_p_wbr w_onebuf_opt.wo_wbr   // 'winbar'
@@ -245,7 +245,7 @@ typedef struct {
 #define w_p_wrap w_onebuf_opt.wo_wrap   // 'wrap'
   int wo_wrap_save;             // 'wrap' state saved for diff mode
 #define w_p_wrap_save w_onebuf_opt.wo_wrap_save
-  char_u *wo_cocu;                 // 'concealcursor'
+  char *wo_cocu;                 // 'concealcursor'
 #define w_p_cocu w_onebuf_opt.wo_cocu
   long wo_cole;                         // 'conceallevel'
 #define w_p_cole w_onebuf_opt.wo_cole
@@ -253,13 +253,13 @@ typedef struct {
 #define w_p_crb w_onebuf_opt.wo_crb    // 'cursorbind'
   int wo_crb_save;              // 'cursorbind' state saved for diff mode
 #define w_p_crb_save w_onebuf_opt.wo_crb_save
-  char_u *wo_scl;
+  char *wo_scl;
 #define w_p_scl w_onebuf_opt.wo_scl    // 'signcolumn'
-  char_u *wo_winhl;
+  char *wo_winhl;
 #define w_p_winhl w_onebuf_opt.wo_winhl    // 'winhighlight'
-  char_u *wo_fcs;
+  char *wo_fcs;
 #define w_p_fcs w_onebuf_opt.wo_fcs    // 'fillchars'
-  char_u *wo_lcs;
+  char *wo_lcs;
 #define w_p_lcs w_onebuf_opt.wo_lcs    // 'listchars'
   long wo_winbl;
 #define w_p_winbl w_onebuf_opt.wo_winbl  // 'winblend'
@@ -308,8 +308,8 @@ typedef struct arglist {
 //
 // TODO(Felipe): move aentry_T to another header
 typedef struct argentry {
-  char_u *ae_fname;        // file name as specified
-  int ae_fnum;                  // buffer number with expanded file name
+  char *ae_fname;        // file name as specified
+  int ae_fnum;           // buffer number with expanded file name
 } aentry_T;
 
 #define ALIST(win) (win)->w_alist
@@ -326,7 +326,7 @@ typedef struct argentry {
  */
 typedef struct {
   char_u *tb_buf;          // buffer for typed characters
-  char_u *tb_noremap;      // mapping flags for characters in tb_buf[]
+  uint8_t *tb_noremap;          // mapping flags for characters in tb_buf[]
   int tb_buflen;                // size of tb_buf[]
   int tb_off;                   // current position in tb_buf[]
   int tb_len;                   // number of valid bytes in tb_buf[]
@@ -352,11 +352,11 @@ typedef struct {
  */
 typedef struct mapblock mapblock_T;
 struct mapblock {
-  mapblock_T *m_next;          // next mapblock in list
-  char_u *m_keys;          // mapped from, lhs
-  char_u *m_str;           // mapped to, rhs
-  char_u *m_orig_str;      // rhs as entered by the user
-  LuaRef m_luaref;         // lua function reference as rhs
+  mapblock_T *m_next;           // next mapblock in list
+  char_u *m_keys;               // mapped from, lhs
+  char *m_str;                  // mapped to, rhs
+  char *m_orig_str;             // rhs as entered by the user
+  LuaRef m_luaref;              // lua function reference as rhs
   int m_keylen;                 // strlen(m_keys)
   int m_mode;                   // valid mode
   int m_simplified;             // m_keys was simplified, do no use this map
@@ -447,7 +447,7 @@ typedef struct {
   linenr_T b_syn_sync_minlines;         // minimal sync lines offset
   linenr_T b_syn_sync_maxlines;         // maximal sync lines offset
   linenr_T b_syn_sync_linebreaks;       // offset for multi-line pattern
-  char_u *b_syn_linecont_pat;           // line continuation pattern
+  char *b_syn_linecont_pat;             // line continuation pattern
   regprog_T *b_syn_linecont_prog;       // line continuation program
   syn_time_T b_syn_linecont_time;
   int b_syn_linecont_ic;                // ignore-case flag for above
@@ -476,17 +476,17 @@ typedef struct {
   disptick_T b_sst_lasttick;    // last display tick
 
   // for spell checking
-  garray_T b_langp;             // list of pointers to slang_T, see spell.c
-  bool b_spell_ismw[256];       // flags: is midword char
-  char_u *b_spell_ismw_mb;  // multi-byte midword chars
-  char_u *b_p_spc;         // 'spellcapcheck'
+  garray_T b_langp;           // list of pointers to slang_T, see spell.c
+  bool b_spell_ismw[256];     // flags: is midword char
+  char *b_spell_ismw_mb;      // multi-byte midword chars
+  char *b_p_spc;              // 'spellcapcheck'
   regprog_T *b_cap_prog;      // program for 'spellcapcheck'
-  char_u *b_p_spf;         // 'spellfile'
-  char_u *b_p_spl;         // 'spelllang'
-  char_u *b_p_spo;         // 'spelloptions'
-  int b_cjk;                    // all CJK letters as OK
-  char_u b_syn_chartab[32];     // syntax iskeyword option
-  char_u *b_syn_isk;            // iskeyword option
+  char *b_p_spf;              // 'spellfile'
+  char *b_p_spl;              // 'spelllang'
+  char *b_p_spo;              // 'spelloptions'
+  int b_cjk;                  // all CJK letters as OK
+  uint8_t b_syn_chartab[32];  // syntax iskeyword option
+  char *b_syn_isk;            // iskeyword option
 } synblock_T;
 
 /// Type used for changedtick_di member in buf_T
@@ -653,10 +653,8 @@ struct file_buffer {
   time_t b_u_time_cur;          // uh_time of header below which we are now
   long b_u_save_nr_cur;         // file write nr after which we are now
 
-  /*
-   * variables for "U" command in undo.c
-   */
-  char_u *b_u_line_ptr;    // saved line for "U" command
+  // variables for "U" command in undo.c
+  char *b_u_line_ptr;           // saved line for "U" command
   linenr_T b_u_line_lnum;       // line number of line in u_line
   colnr_T b_u_line_colnr;       // optional column number
 
@@ -686,72 +684,72 @@ struct file_buffer {
 
   int b_p_ai;                   ///< 'autoindent'
   int b_p_ai_nopaste;           ///< b_p_ai saved for paste mode
-  char_u *b_p_bkc;              ///< 'backupco
+  char *b_p_bkc;                ///< 'backupco
   unsigned int b_bkc_flags;     ///< flags for 'backupco
   int b_p_ci;                   ///< 'copyindent'
   int b_p_bin;                  ///< 'binary'
   int b_p_bomb;                 ///< 'bomb'
-  char_u *b_p_bh;               ///< 'bufhidden'
-  char_u *b_p_bt;               ///< 'buftype'
+  char *b_p_bh;                 ///< 'bufhidden'
+  char *b_p_bt;                 ///< 'buftype'
   int b_has_qf_entry;           ///< quickfix exists for buffer
   int b_p_bl;                   ///< 'buflisted'
   long b_p_channel;             ///< 'channel'
   int b_p_cin;                  ///< 'cindent'
-  char_u *b_p_cino;             ///< 'cinoptions'
-  char_u *b_p_cink;             ///< 'cinkeys'
-  char_u *b_p_cinw;             ///< 'cinwords'
-  char_u *b_p_cinsd;            ///< 'cinscopedecls'
-  char_u *b_p_com;              ///< 'comments'
-  char_u *b_p_cms;              ///< 'commentstring'
-  char_u *b_p_cpt;              ///< 'complete'
+  char *b_p_cino;               ///< 'cinoptions'
+  char *b_p_cink;               ///< 'cinkeys'
+  char *b_p_cinw;               ///< 'cinwords'
+  char *b_p_cinsd;              ///< 'cinscopedecls'
+  char *b_p_com;                ///< 'comments'
+  char *b_p_cms;                ///< 'commentstring'
+  char *b_p_cpt;                ///< 'complete'
 #ifdef BACKSLASH_IN_FILENAME
   char_u *b_p_csl;              ///< 'completeslash'
 #endif
-  char_u *b_p_cfu;              ///< 'completefunc'
-  char_u *b_p_ofu;              ///< 'omnifunc'
-  char_u *b_p_tfu;              ///< 'tagfunc'
+  char *b_p_cfu;                ///< 'completefunc'
+  char *b_p_ofu;                ///< 'omnifunc'
+  char *b_p_tfu;                ///< 'tagfunc'
   int b_p_eol;                  ///< 'endofline'
   int b_p_fixeol;               ///< 'fixendofline'
   int b_p_et;                   ///< 'expandtab'
   int b_p_et_nobin;             ///< b_p_et saved for binary mode
   int b_p_et_nopaste;           ///< b_p_et saved for paste mode
-  char_u *b_p_fenc;             ///< 'fileencoding'
-  char_u *b_p_ff;               ///< 'fileformat'
-  char_u *b_p_ft;               ///< 'filetype'
-  char_u *b_p_fo;               ///< 'formatoptions'
-  char_u *b_p_flp;              ///< 'formatlistpat'
+  char *b_p_fenc;               ///< 'fileencoding'
+  char *b_p_ff;                 ///< 'fileformat'
+  char *b_p_ft;                 ///< 'filetype'
+  char *b_p_fo;                 ///< 'formatoptions'
+  char *b_p_flp;                ///< 'formatlistpat'
   int b_p_inf;                  ///< 'infercase'
-  char_u *b_p_isk;              ///< 'iskeyword'
-  char_u *b_p_def;              ///< 'define' local value
-  char_u *b_p_inc;              ///< 'include'
-  char_u *b_p_inex;             ///< 'includeexpr'
+  char *b_p_isk;                ///< 'iskeyword'
+  char *b_p_def;                ///< 'define' local value
+  char *b_p_inc;                ///< 'include'
+  char *b_p_inex;               ///< 'includeexpr'
   uint32_t b_p_inex_flags;      ///< flags for 'includeexpr'
-  char_u *b_p_inde;             ///< 'indentexpr'
+  char *b_p_inde;               ///< 'indentexpr'
   uint32_t b_p_inde_flags;      ///< flags for 'indentexpr'
-  char_u *b_p_indk;             ///< 'indentkeys'
-  char_u *b_p_fp;               ///< 'formatprg'
-  char_u *b_p_fex;              ///< 'formatexpr'
+  char *b_p_indk;               ///< 'indentkeys'
+  char *b_p_fp;                 ///< 'formatprg'
+  char *b_p_fex;                ///< 'formatexpr'
   uint32_t b_p_fex_flags;       ///< flags for 'formatexpr'
-  char_u *b_p_kp;               ///< 'keywordprg'
+  char *b_p_kp;                 ///< 'keywordprg'
   int b_p_lisp;                 ///< 'lisp'
-  char_u *b_p_menc;             ///< 'makeencoding'
-  char_u *b_p_mps;              ///< 'matchpairs'
+  char *b_p_menc;               ///< 'makeencoding'
+  char *b_p_mps;                ///< 'matchpairs'
   int b_p_ml;                   ///< 'modeline'
   int b_p_ml_nobin;             ///< b_p_ml saved for binary mode
   int b_p_ma;                   ///< 'modifiable'
-  char_u *b_p_nf;               ///< 'nrformats'
+  char *b_p_nf;                 ///< 'nrformats'
   int b_p_pi;                   ///< 'preserveindent'
-  char_u *b_p_qe;               ///< 'quoteescape'
+  char *b_p_qe;                 ///< 'quoteescape'
   int b_p_ro;                   ///< 'readonly'
   long b_p_sw;                  ///< 'shiftwidth'
   long b_p_scbk;                ///< 'scrollback'
   int b_p_si;                   ///< 'smartindent'
   long b_p_sts;                 ///< 'softtabstop'
   long b_p_sts_nopaste;         ///< b_p_sts saved for paste mode
-  char_u *b_p_sua;              ///< 'suffixesadd'
+  char *b_p_sua;                ///< 'suffixesadd'
   int b_p_swf;                  ///< 'swapfile'
   long b_p_smc;                 ///< 'synmaxcol'
-  char_u *b_p_syn;              ///< 'syntax'
+  char *b_p_syn;                ///< 'syntax'
   long b_p_ts;                  ///< 'tabstop'
   long b_p_tw;                  ///< 'textwidth'
   long b_p_tw_nobin;            ///< b_p_tw saved for binary mode
@@ -759,29 +757,29 @@ struct file_buffer {
   long b_p_wm;                  ///< 'wrapmargin'
   long b_p_wm_nobin;            ///< b_p_wm saved for binary mode
   long b_p_wm_nopaste;          ///< b_p_wm saved for paste mode
-  char_u *b_p_vsts;             ///< 'varsofttabstop'
-  long *b_p_vsts_array;          ///< 'varsofttabstop' in internal format
-  char_u *b_p_vsts_nopaste;     ///< b_p_vsts saved for paste mode
-  char_u *b_p_vts;              ///< 'vartabstop'
-  long *b_p_vts_array;           ///< 'vartabstop' in internal format
-  char_u *b_p_keymap;           ///< 'keymap'
+  char *b_p_vsts;               ///< 'varsofttabstop'
+  long *b_p_vsts_array;         ///< 'varsofttabstop' in internal format
+  char *b_p_vsts_nopaste;       ///< b_p_vsts saved for paste mode
+  char *b_p_vts;                ///< 'vartabstop'
+  long *b_p_vts_array;          ///< 'vartabstop' in internal format
+  char *b_p_keymap;             ///< 'keymap'
 
   // local values for options which are normally global
-  char_u *b_p_gp;               ///< 'grepprg' local value
-  char_u *b_p_mp;               ///< 'makeprg' local value
-  char_u *b_p_efm;              ///< 'errorformat' local value
-  char_u *b_p_ep;               ///< 'equalprg' local value
-  char_u *b_p_path;             ///< 'path' local value
+  char *b_p_gp;                 ///< 'grepprg' local value
+  char *b_p_mp;                 ///< 'makeprg' local value
+  char *b_p_efm;                ///< 'errorformat' local value
+  char *b_p_ep;                 ///< 'equalprg' local value
+  char *b_p_path;               ///< 'path' local value
   int b_p_ar;                   ///< 'autoread' local value
-  char_u *b_p_tags;             ///< 'tags' local value
-  char_u *b_p_tc;               ///< 'tagcase' local value
+  char *b_p_tags;               ///< 'tags' local value
+  char *b_p_tc;                 ///< 'tagcase' local value
   unsigned b_tc_flags;          ///< flags for 'tagcase'
-  char_u *b_p_dict;             ///< 'dictionary' local value
-  char_u *b_p_tsr;              ///< 'thesaurus' local value
-  char_u *b_p_tsrfu;            ///< 'thesaurusfunc' local value
+  char *b_p_dict;               ///< 'dictionary' local value
+  char *b_p_tsr;                ///< 'thesaurus' local value
+  char *b_p_tsrfu;              ///< 'thesaurusfunc' local value
   long b_p_ul;                  ///< 'undolevels' local value
   int b_p_udf;                  ///< 'undofile'
-  char_u *b_p_lw;               ///< 'lispwords' local value
+  char *b_p_lw;                 ///< 'lispwords' local value
 
   // end of buffer options
 
diff --git a/src/nvim/change.c b/src/nvim/change.c
index ab54c3ea88..45ff2ceacb 100644
--- a/src/nvim/change.c
+++ b/src/nvim/change.c
@@ -536,9 +536,9 @@ void unchanged(buf_T *buf, int ff, bool always_inc_changedtick)
 
 /// Insert string "p" at the cursor position.  Stops at a NUL byte.
 /// Handles Replace mode and multi-byte characters.
-void ins_bytes(char_u *p)
+void ins_bytes(char *p)
 {
-  ins_bytes_len(p, STRLEN(p));
+  ins_bytes_len((char_u *)p, STRLEN(p));
 }
 
 /// Insert string "p" with length "len" at the cursor position.
@@ -1309,10 +1309,10 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
 
         // Doing "O" on the end of a comment inserts the middle leader.
         // Find the string for the middle leader, searching backwards.
-        while (p > (char *)curbuf->b_p_com && *p != ',') {
+        while (p > curbuf->b_p_com && *p != ',') {
           p--;
         }
-        for (lead_repl = p; lead_repl > (char *)curbuf->b_p_com
+        for (lead_repl = p; lead_repl > curbuf->b_p_com
              && lead_repl[-1] != ':'; lead_repl--) {}
         lead_repl_len = (int)(p - lead_repl);
 
@@ -1795,7 +1795,7 @@ int open_line(int dir, int flags, int second_line_indent, bool *did_do_comment)
     // Insert new stuff into line again
     curwin->w_cursor.col = 0;
     curwin->w_cursor.coladd = 0;
-    ins_bytes(p_extra);         // will call changed_bytes()
+    ins_bytes((char *)p_extra);         // will call changed_bytes()
     xfree(p_extra);
     next_line = NULL;
   }
@@ -1814,16 +1814,16 @@ theend:
 /// If "fixpos" is true fix the cursor position when done.
 void truncate_line(int fixpos)
 {
-  char_u *newp;
+  char *newp;
   linenr_T lnum = curwin->w_cursor.lnum;
   colnr_T col = curwin->w_cursor.col;
 
   if (col == 0) {
-    newp = vim_strsave((char_u *)"");
+    newp = xstrdup("");
   } else {
-    newp = vim_strnsave(ml_get(lnum), (size_t)col);
+    newp = (char *)vim_strnsave(ml_get(lnum), (size_t)col);
   }
-  ml_replace(lnum, (char *)newp, false);
+  ml_replace(lnum, newp, false);
 
   // mark the buffer as changed and prepare for displaying
   changed_bytes(lnum, curwin->w_cursor.col);
@@ -1900,7 +1900,7 @@ 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 = (char *)curbuf->b_p_com; *list;) {
+    for (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) {
@@ -2037,7 +2037,7 @@ int get_last_leader_offset(char *line, char **flags)
   while (--i >= lower_check_bound) {
     // scan through the 'comments' option for a match
     int found_one = false;
-    for (list = (char *)curbuf->b_p_com; *list;) {
+    for (list = curbuf->b_p_com; *list;) {
       char *flags_save = list;
 
       // Get one option part into part_buf[].  Advance list to next one.
@@ -2122,7 +2122,7 @@ int get_last_leader_offset(char *line, char **flags)
       }
       len1 = (int)STRLEN(com_leader);
 
-      for (list = (char *)curbuf->b_p_com; *list;) {
+      for (list = curbuf->b_p_com; *list;) {
         char *flags_save = list;
 
         (void)copy_option_part(&list, part_buf2, COM_MAX_LEN, ",");
diff --git a/src/nvim/charset.c b/src/nvim/charset.c
index 6238d85b3a..ff58810ff0 100644
--- a/src/nvim/charset.c
+++ b/src/nvim/charset.c
@@ -149,7 +149,7 @@ int buf_init_chartab(buf_T *buf, int global)
       p = p_isf;
     } else {  // i == 3
       // fourth round: 'iskeyword'
-      p = buf->b_p_isk;
+      p = (char_u *)buf->b_p_isk;
     }
 
     while (*p) {
diff --git a/src/nvim/diff.c b/src/nvim/diff.c
index 90d621ae1e..fa1c669aaf 100644
--- a/src/nvim/diff.c
+++ b/src/nvim/diff.c
@@ -797,8 +797,8 @@ static int diff_write(buf_T *buf, diffin_T *din)
   }
 
   // Always use 'fileformat' set to "unix".
-  char_u *save_ff = buf->b_p_ff;
-  buf->b_p_ff = vim_strsave((char_u *)FF_UNIX);
+  char *save_ff = buf->b_p_ff;
+  buf->b_p_ff = xstrdup(FF_UNIX);
   const bool save_cmod_flags = cmdmod.cmod_flags;
   // Writing the buffer is an implementation detail of performing the diff,
   // so it shouldn't update the '[ and '] marks.
@@ -1413,7 +1413,7 @@ void diff_win_options(win_T *wp, int addbuf)
     if (wp->w_p_diff_saved) {
       free_string_option(wp->w_p_fdm_save);
     }
-    wp->w_p_fdm_save = vim_strsave(wp->w_p_fdm);
+    wp->w_p_fdm_save = xstrdup(wp->w_p_fdm);
   }
   set_string_option_direct_in_win(wp, "fdm", -1, "diff", OPT_LOCAL | OPT_FREE, 0);
 
@@ -1424,12 +1424,12 @@ void diff_win_options(win_T *wp, int addbuf)
     if (wp->w_p_diff_saved) {
       free_string_option(wp->w_p_fdc_save);
     }
-    wp->w_p_fdc_save = vim_strsave(wp->w_p_fdc);
+    wp->w_p_fdc_save = xstrdup(wp->w_p_fdc);
   }
   free_string_option(wp->w_p_fdc);
-  wp->w_p_fdc = (char_u *)xstrdup("2");
+  wp->w_p_fdc = xstrdup("2");
   assert(diff_foldcolumn >= 0 && diff_foldcolumn <= 9);
-  snprintf((char *)wp->w_p_fdc, STRLEN(wp->w_p_fdc) + 1, "%d", diff_foldcolumn);
+  snprintf(wp->w_p_fdc, STRLEN(wp->w_p_fdc) + 1, "%d", diff_foldcolumn);
   wp->w_p_fen = true;
   wp->w_p_fdl = 0;
   foldUpdateAll(wp);
@@ -1480,11 +1480,9 @@ void ex_diffoff(exarg_T *eap)
           }
         }
         free_string_option(wp->w_p_fdm);
-        wp->w_p_fdm = vim_strsave(*wp->w_p_fdm_save
-                                  ? wp->w_p_fdm_save
-                                  : (char_u *)"manual");
+        wp->w_p_fdm = xstrdup(*wp->w_p_fdm_save ? wp->w_p_fdm_save : "manual");
         free_string_option(wp->w_p_fdc);
-        wp->w_p_fdc = vim_strsave(wp->w_p_fdc_save);
+        wp->w_p_fdc = xstrdup(wp->w_p_fdc_save);
 
         if (wp->w_p_fdl == 0) {
           wp->w_p_fdl = wp->w_p_fdl_save;
diff --git a/src/nvim/drawline.c b/src/nvim/drawline.c
index 2b1b2607fb..f1a808e2bc 100644
--- a/src/nvim/drawline.c
+++ b/src/nvim/drawline.c
@@ -2082,7 +2082,7 @@ int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow, bool nochange,
       if (wp->w_p_cole > 0
           && (wp != curwin || lnum != wp->w_cursor.lnum || conceal_cursor_line(wp))
           && ((syntax_flags & HL_CONCEAL) != 0 || has_match_conc > 0 || decor_conceal > 0)
-          && !(lnum_in_visual_area && vim_strchr((char *)wp->w_p_cocu, 'v') == NULL)) {
+          && !(lnum_in_visual_area && vim_strchr(wp->w_p_cocu, 'v') == NULL)) {
         char_attr = conceal_attr;
         if (((prev_syntax_id != syntax_seqnr && (syntax_flags & HL_CONCEAL) != 0)
              || has_match_conc > 1 || decor_conceal > 1)
diff --git a/src/nvim/edit.c b/src/nvim/edit.c
index 79317d3df6..5fc19f9409 100644
--- a/src/nvim/edit.c
+++ b/src/nvim/edit.c
@@ -1780,7 +1780,7 @@ void change_indent(int type, int amount, int round, int replaced, int call_chang
     backspace_until_column(0);
 
     // Insert new stuff into line again
-    ins_bytes(new_line);
+    ins_bytes((char *)new_line);
 
     xfree(new_line);
 
@@ -2595,7 +2595,7 @@ static void internal_format(int textwidth, int second_indent, int flags, int for
     if (State & VREPLACE_FLAG) {
       // In MODE_VREPLACE state we have backspaced over the text to be
       // moved, now we re-insert it into the new line.
-      ins_bytes(saved_text);
+      ins_bytes((char *)saved_text);
       xfree(saved_text);
     } else {
       /*
@@ -3689,9 +3689,9 @@ bool in_cinkeys(int keytyped, int when, bool line_is_empty)
   }
 
   if (*curbuf->b_p_inde != NUL) {
-    look = curbuf->b_p_indk;            // 'indentexpr' set: use 'indentkeys'
+    look = (char_u *)curbuf->b_p_indk;            // 'indentexpr' set: use 'indentkeys'
   } else {
-    look = curbuf->b_p_cink;            // 'indentexpr' empty: use 'cinkeys'
+    look = (char_u *)curbuf->b_p_cink;            // 'indentexpr' empty: use 'cinkeys'
   }
   while (*look) {
     /*
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index 1458d1ff36..6d37106143 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -2192,7 +2192,7 @@ int pattern_match(char *pat, char *text, bool ic)
 
   // avoid 'l' flag in 'cpoptions'
   char *save_cpo = p_cpo;
-  p_cpo = (char *)empty_option;
+  p_cpo = empty_option;
   regmatch.regprog = vim_regcomp(pat, RE_MAGIC + RE_STRING);
   if (regmatch.regprog != NULL) {
     regmatch.rm_ic = ic;
@@ -8326,7 +8326,7 @@ char *do_string_sub(char *str, char *pat, char *sub, typval_T *expr, char *flags
 
   // Make 'cpoptions' empty, so that the 'l' flag doesn't work here
   char *save_cpo = p_cpo;
-  p_cpo = (char *)empty_option;
+  p_cpo = empty_option;
 
   ga_init(&ga, 1, 200);
 
@@ -8386,7 +8386,7 @@ char *do_string_sub(char *str, char *pat, char *sub, typval_T *expr, char *flags
 
   char *ret = xstrdup(ga.ga_data == NULL ? str : ga.ga_data);
   ga_clear(&ga);
-  if ((char_u *)p_cpo == empty_option) {
+  if (p_cpo == empty_option) {
     p_cpo = save_cpo;
   } else {
     // Darn, evaluating {sub} expression or {expr} changed the value.
@@ -8395,7 +8395,7 @@ char *do_string_sub(char *str, char *pat, char *sub, typval_T *expr, char *flags
     if (*p_cpo == NUL) {
       set_option_value_give_err("cpo", 0L, save_cpo, 0);
     }
-    free_string_option((char_u *)save_cpo);
+    free_string_option(save_cpo);
   }
 
   return ret;
diff --git a/src/nvim/eval/funcs.c b/src/nvim/eval/funcs.c
index fc926cf5a9..ff5d8a0a8f 100644
--- a/src/nvim/eval/funcs.c
+++ b/src/nvim/eval/funcs.c
@@ -591,7 +591,7 @@ buf_T *tv_get_buf(typval_T *tv, int curtab_only)
   int save_magic = p_magic;
   p_magic = true;
   char *save_cpo = p_cpo;
-  p_cpo = (char *)empty_option;
+  p_cpo = empty_option;
 
   buf_T *buf = buflist_findnr(buflist_findpat((char *)name, (char *)name + STRLEN(name),
                                               true, false, curtab_only));
@@ -2224,7 +2224,7 @@ static void f_filewritable(typval_T *argvars, typval_T *rettv, EvalFuncData fptr
 static void findfilendir(typval_T *argvars, typval_T *rettv, int find_what)
 {
   char_u *fresult = NULL;
-  char_u *path = *curbuf->b_p_path == NUL ? p_path : curbuf->b_p_path;
+  char_u *path = *curbuf->b_p_path == NUL ? p_path : (char_u *)curbuf->b_p_path;
   int count = 1;
   bool first = true;
   bool error = false;
@@ -2265,7 +2265,7 @@ static void findfilendir(typval_T *argvars, typval_T *rettv, int find_what)
                                          find_what, (char_u *)curbuf->b_ffname,
                                          (find_what == FINDFILE_DIR
                                           ? (char_u *)""
-                                          : curbuf->b_p_sua));
+                                          : (char_u *)curbuf->b_p_sua));
       first = false;
 
       if (fresult != NULL && rettv->v_type == VAR_LIST) {
@@ -4903,7 +4903,7 @@ static void find_some_match(typval_T *const argvars, typval_T *const rettv,
 
   // Make 'cpoptions' empty, the 'l' flag should not be used here.
   char *save_cpo = p_cpo;
-  p_cpo = (char *)empty_option;
+  p_cpo = empty_option;
 
   rettv->vval.v_number = -1;
   switch (type) {
@@ -6312,7 +6312,7 @@ static void f_resolve(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
       v = os_realpath(fname, v);
     }
   }
-  rettv->vval.v_string = (char_u *)(v == NULL ? xstrdup(fname) : v);
+  rettv->vval.v_string = (v == NULL ? xstrdup(fname) : v);
 #else
 # ifdef HAVE_READLINK
   {
@@ -7293,7 +7293,7 @@ long do_searchpair(const char *spat, const char *mpat, const char *epat, int dir
 
   // Make 'cpoptions' empty, the 'l' flag should not be used here.
   char *save_cpo = p_cpo;
-  p_cpo = (char *)empty_option;
+  p_cpo = empty_option;
 
   // Set the time limit, if there is one.
   proftime_T tm = profile_setlimit(time_limit);
@@ -7419,7 +7419,7 @@ long do_searchpair(const char *spat, const char *mpat, const char *epat, int dir
 
   xfree(pat2);
   xfree(pat3);
-  if ((char_u *)p_cpo == empty_option) {
+  if (p_cpo == empty_option) {
     p_cpo = save_cpo;
   } else {
     // Darn, evaluating the {skip} expression changed the value.
@@ -7428,7 +7428,7 @@ long do_searchpair(const char *spat, const char *mpat, const char *epat, int dir
     if (*p_cpo == NUL) {
       set_option_value_give_err("cpo", 0L, save_cpo, 0);
     }
-    free_string_option((char_u *)save_cpo);
+    free_string_option(save_cpo);
   }
 
   return retval;
@@ -8182,7 +8182,7 @@ static void f_split(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
 
   // Make 'cpoptions' empty, the 'l' flag should not be used here.
   char *save_cpo = p_cpo;
-  p_cpo = (char *)empty_option;
+  p_cpo = empty_option;
 
   const char *str = tv_get_string(&argvars[0]);
   const char *pat = NULL;
diff --git a/src/nvim/ex_cmds2.c b/src/nvim/ex_cmds2.c
index 2ed45f7ab8..41512205dc 100644
--- a/src/nvim/ex_cmds2.c
+++ b/src/nvim/ex_cmds2.c
@@ -680,11 +680,11 @@ void ex_listdo(exarg_T *eap)
         // buffer was opened while Syntax autocommands were disabled,
         // need to trigger them now.
         if (buf == curbuf) {
-          apply_autocmds(EVENT_SYNTAX, (char *)curbuf->b_p_syn, curbuf->b_fname, true,
+          apply_autocmds(EVENT_SYNTAX, curbuf->b_p_syn, curbuf->b_fname, true,
                          curbuf);
         } else {
           aucmd_prepbuf(&aco, buf);
-          apply_autocmds(EVENT_SYNTAX, (char *)buf->b_p_syn, buf->b_fname, true, buf);
+          apply_autocmds(EVENT_SYNTAX, buf->b_p_syn, buf->b_fname, true, buf);
           aucmd_restbuf(&aco);
         }
 
diff --git a/src/nvim/ex_docmd.c b/src/nvim/ex_docmd.c
index 8f2a98b401..29812dd8fe 100644
--- a/src/nvim/ex_docmd.c
+++ b/src/nvim/ex_docmd.c
@@ -2602,7 +2602,7 @@ void undo_cmdmod(cmdmod_T *cmod)
   if (cmod->cmod_save_ei != NULL) {
     // Restore 'eventignore' to the value before ":noautocmd".
     set_string_option_direct("ei", -1, cmod->cmod_save_ei, OPT_FREE, SID_NONE);
-    free_string_option((char_u *)cmod->cmod_save_ei);
+    free_string_option(cmod->cmod_save_ei);
     cmod->cmod_save_ei = NULL;
   }
 
@@ -3646,8 +3646,8 @@ char *replace_makeprg(exarg_T *eap, char *arg, char **cmdlinep)
   // Don't do it when ":vimgrep" is used for ":grep".
   if ((eap->cmdidx == CMD_make || eap->cmdidx == CMD_lmake || isgrep)
       && !grep_internal(eap->cmdidx)) {
-    const char *program = isgrep ? (*curbuf->b_p_gp == NUL ? (char *)p_gp : (char *)curbuf->b_p_gp)
-                                 : (*curbuf->b_p_mp == NUL ? (char *)p_mp : (char *)curbuf->b_p_mp);
+    const char *program = isgrep ? (*curbuf->b_p_gp == NUL ? (char *)p_gp : curbuf->b_p_gp)
+                                 : (*curbuf->b_p_mp == NUL ? (char *)p_mp : curbuf->b_p_mp);
 
     arg = skipwhite(arg);
 
diff --git a/src/nvim/ex_eval.c b/src/nvim/ex_eval.c
index 5ddcb0270b..8941921568 100644
--- a/src/nvim/ex_eval.c
+++ b/src/nvim/ex_eval.c
@@ -1376,7 +1376,7 @@ void ex_catch(exarg_T *eap)
           *end = NUL;
         }
         save_cpo = p_cpo;
-        p_cpo = (char *)empty_option;
+        p_cpo = empty_option;
         // Disable error messages, it will make current exception
         // invalid
         emsg_off++;
diff --git a/src/nvim/ex_session.c b/src/nvim/ex_session.c
index 9495ae1c4b..453de89aea 100644
--- a/src/nvim/ex_session.c
+++ b/src/nvim/ex_session.c
@@ -359,7 +359,7 @@ static int put_view(FILE *fd, win_T *wp, int add_edit, unsigned *flagp, int curr
       // Then ":help" will re-use both the buffer and the window and set
       // the options, even when "options" is not in 'sessionoptions'.
       if (0 < wp->w_tagstackidx && wp->w_tagstackidx <= wp->w_tagstacklen) {
-        curtag = (char *)wp->w_tagstack[wp->w_tagstackidx - 1].tagname;
+        curtag = wp->w_tagstack[wp->w_tagstackidx - 1].tagname;
       }
 
       if (put_line(fd, "enew | setl bt=help") == FAIL
diff --git a/src/nvim/file_search.c b/src/nvim/file_search.c
index 53f87d0e42..2e86e3f7b0 100644
--- a/src/nvim/file_search.c
+++ b/src/nvim/file_search.c
@@ -827,7 +827,7 @@ char_u *vim_findfile(void *search_ctx_arg)
             if (search_ctx->ffsc_tagfile) {
               suf = "";
             } else {
-              suf = (char *)curbuf->b_p_sua;
+              suf = curbuf->b_p_sua;
             }
             for (;;) {
               // if file exists and we didn't already find it
@@ -1355,8 +1355,8 @@ char_u *find_file_in_path(char_u *ptr, size_t len, int options, int first, char_
   return find_file_in_path_option(ptr, len, options, first,
                                   (*curbuf->b_p_path == NUL
                                    ? p_path
-                                   : curbuf->b_p_path),
-                                  FINDFILE_BOTH, rel_fname, curbuf->b_p_sua);
+                                   : (char_u *)curbuf->b_p_path),
+                                  FINDFILE_BOTH, rel_fname, (char_u *)curbuf->b_p_sua);
 }
 
 static char_u *ff_file_to_find = NULL;
diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index 39bf1b3670..cc592c2430 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -708,7 +708,7 @@ int readfile(char *fname, char *sfname, linenr_T from, linenr_T lines_to_skip,
 
     fenc_alloced = false;
   } else if (*p_fencs == NUL) {
-    fenc = (char *)curbuf->b_p_fenc;            // use format from buffer
+    fenc = curbuf->b_p_fenc;            // use format from buffer
     fenc_alloced = false;
   } else {
     fenc_next = (char *)p_fencs;                // try items in 'fileencodings'
@@ -1948,7 +1948,7 @@ failed:
       if (!au_did_filetype && *curbuf->b_p_ft != NUL) {
         // EVENT_FILETYPE was not triggered but the buffer already has a
         // filetype.  Trigger EVENT_FILETYPE using the existing filetype.
-        apply_autocmds(EVENT_FILETYPE, (char *)curbuf->b_p_ft, curbuf->b_fname, true, curbuf);
+        apply_autocmds(EVENT_FILETYPE, curbuf->b_p_ft, curbuf->b_fname, true, curbuf);
       }
     } else {
       apply_autocmds_exarg(EVENT_FILEREADPOST, sfname, sfname,
@@ -3052,7 +3052,7 @@ nobackup:
     fenc = (char *)enc_canonize((char_u *)fenc);
     fenc_tofree = fenc;
   } else {
-    fenc = (char *)buf->b_p_fenc;
+    fenc = buf->b_p_fenc;
   }
 
   // Check if the file needs to be converted.
diff --git a/src/nvim/fold.c b/src/nvim/fold.c
index 9cc17acb37..b4ddb3ec08 100644
--- a/src/nvim/fold.c
+++ b/src/nvim/fold.c
@@ -1556,7 +1556,7 @@ static void foldCreateMarkers(win_T *wp, pos_T start, pos_T end)
   }
   parseMarker(wp);
 
-  foldAddMarker(buf, start, wp->w_p_fmr, foldstartmarkerlen);
+  foldAddMarker(buf, start, (char_u *)wp->w_p_fmr, foldstartmarkerlen);
   foldAddMarker(buf, end, foldendmarker, foldendmarkerlen);
 
   // Update both changes here, to avoid all folds after the start are
@@ -1575,9 +1575,9 @@ static void foldCreateMarkers(win_T *wp, pos_T start, pos_T end)
 /// Add "marker[markerlen]" in 'commentstring' to position `pos`.
 static void foldAddMarker(buf_T *buf, pos_T pos, const char_u *marker, size_t markerlen)
 {
-  char_u *cms = buf->b_p_cms;
+  char_u *cms = (char_u *)buf->b_p_cms;
   char_u *newline;
-  char_u *p = (char_u *)strstr((char *)buf->b_p_cms, "%s");
+  char_u *p = (char_u *)strstr(buf->b_p_cms, "%s");
   bool line_is_comment = false;
   linenr_T lnum = pos.lnum;
 
@@ -1621,7 +1621,7 @@ static void deleteFoldMarkers(win_T *wp, fold_T *fp, int recursive, linenr_T lnu
                         lnum_off + fp->fd_top);
     }
   }
-  foldDelMarker(wp->w_buffer, fp->fd_top + lnum_off, wp->w_p_fmr,
+  foldDelMarker(wp->w_buffer, fp->fd_top + lnum_off, (char_u *)wp->w_p_fmr,
                 foldstartmarkerlen);
   foldDelMarker(wp->w_buffer, fp->fd_top + lnum_off + fp->fd_len - 1,
                 foldendmarker, foldendmarkerlen);
@@ -1639,7 +1639,7 @@ static void foldDelMarker(buf_T *buf, linenr_T lnum, char_u *marker, size_t mark
     return;
   }
 
-  char_u *cms = buf->b_p_cms;
+  char_u *cms = (char_u *)buf->b_p_cms;
   char_u *line = ml_get_buf(buf, lnum, false);
   for (char_u *p = line; *p != NUL; p++) {
     if (STRNCMP(p, marker, markerlen) != 0) {
@@ -1729,7 +1729,7 @@ char_u *get_foldtext(win_T *wp, linenr_T lnum, linenr_T lnume, foldinfo_T foldin
 
       emsg_silent++;       // handle exceptions, but don't display errors
       text =
-        (char_u *)eval_to_string_safe((char *)wp->w_p_fdt, NULL,
+        (char_u *)eval_to_string_safe(wp->w_p_fdt, NULL,
                                       was_set_insecurely(wp, "foldtext", OPT_LOCAL));
       emsg_silent--;
 
@@ -1790,7 +1790,7 @@ char_u *get_foldtext(win_T *wp, linenr_T lnum, linenr_T lnume, foldinfo_T foldin
 static void foldtext_cleanup(char_u *str)
 {
   // Ignore leading and trailing white space in 'commentstring'.
-  char_u *cms_start = (char_u *)skipwhite((char *)curbuf->b_p_cms);
+  char_u *cms_start = (char_u *)skipwhite(curbuf->b_p_cms);
   size_t cms_slen = STRLEN(cms_start);
   while (cms_slen > 0 && ascii_iswhite(cms_start[cms_slen - 1])) {
     cms_slen--;
@@ -2854,7 +2854,7 @@ static void foldlevelIndent(fline_T *flp)
 
   // empty line or lines starting with a character in 'foldignore': level
   // depends on surrounding lines
-  if (*s == NUL || vim_strchr((char *)flp->wp->w_p_fdi, *s) != NULL) {
+  if (*s == NUL || vim_strchr(flp->wp->w_p_fdi, *s) != NULL) {
     // first and last line can't be undefined, use level 0
     if (lnum == 1 || lnum == buf->b_ml.ml_line_count) {
       flp->lvl = 0;
@@ -2907,7 +2907,7 @@ static void foldlevelExpr(fline_T *flp)
   const bool save_keytyped = KeyTyped;
 
   int c;
-  const int n = eval_foldexpr((char *)flp->wp->w_p_fde, &c);
+  const int n = eval_foldexpr(flp->wp->w_p_fde, &c);
   KeyTyped = save_keytyped;
 
   switch (c) {
@@ -2985,8 +2985,8 @@ static void foldlevelExpr(fline_T *flp)
 /// Relies on the option value to have been checked for correctness already.
 static void parseMarker(win_T *wp)
 {
-  foldendmarker = (char_u *)vim_strchr((char *)wp->w_p_fmr, ',');
-  foldstartmarkerlen = (size_t)(foldendmarker++ - wp->w_p_fmr);
+  foldendmarker = (char_u *)vim_strchr(wp->w_p_fmr, ',');
+  foldstartmarkerlen = (size_t)(foldendmarker++ - (char_u *)wp->w_p_fmr);
   foldendmarkerlen = STRLEN(foldendmarker);
 }
 
@@ -3003,7 +3003,7 @@ static void foldlevelMarker(fline_T *flp)
   int start_lvl = flp->lvl;
 
   // cache a few values for speed
-  char_u *startmarker = flp->wp->w_p_fmr;
+  char_u *startmarker = (char_u *)flp->wp->w_p_fmr;
   int cstart = *startmarker;
   startmarker++;
   int cend = *foldendmarker;
diff --git a/src/nvim/getchar.c b/src/nvim/getchar.c
index 1f4d28bcd3..e858b9244b 100644
--- a/src/nvim/getchar.c
+++ b/src/nvim/getchar.c
@@ -162,7 +162,7 @@ static char_u *get_buffcont(buffheader_T *buffer, int dozero)
     p2 = p;
     for (const buffblock_T *bp = buffer->bh_first.b_next;
          bp != NULL; bp = bp->b_next) {
-      for (const char_u *str = bp->b_str; *str;) {
+      for (const char_u *str = (char_u *)bp->b_str; *str;) {
         *p2++ = *str++;
       }
     }
@@ -341,7 +341,7 @@ static int read_readbuf(buffheader_T *buf, int advance)
   }
 
   buffblock_T *const curr = buf->bh_first.b_next;
-  c = curr->b_str[buf->bh_index];
+  c = (char_u)curr->b_str[buf->bh_index];
 
   if (advance) {
     if (curr->b_str[++buf->bh_index] == NUL) {
@@ -649,7 +649,7 @@ static int read_redo(bool init, bool old_redo)
     if (bp == NULL) {
       return FAIL;
     }
-    p = bp->b_str;
+    p = (char_u *)bp->b_str;
     return OK;
   }
   if ((c = *p) == NUL) {
@@ -670,7 +670,7 @@ static int read_redo(bool init, bool old_redo)
     }
     if (*++p == NUL && bp->b_next != NULL) {
       bp = bp->b_next;
-      p = bp->b_str;
+      p = (char_u *)bp->b_str;
     }
     buf[i] = (char_u)c;
     if (i == n - 1) {         // last byte of a character
@@ -934,7 +934,7 @@ int ins_typebuf(char *str, int noremap, int offset, bool nottyped, bool silent)
   }
   for (i = 0; i < addlen; i++) {
     typebuf.tb_noremap[typebuf.tb_off + i + offset] =
-      (char_u)((--nrm >= 0) ? val : RM_YES);
+      (uint8_t)((--nrm >= 0) ? val : RM_YES);
   }
 
   // tb_maplen and tb_silent only remember the length of mapped and/or
@@ -2047,12 +2047,11 @@ static int handle_mapping(int *keylenp, bool *timedout, int *mapdepth)
         // - Partly match: mlen == typebuf.tb_len
         keylen = mp->m_keylen;
         if (mlen == keylen || (mlen == typebuf.tb_len && typebuf.tb_len < keylen)) {
-          char_u *s;
           int n;
 
           // If only script-local mappings are allowed, check if the
           // mapping starts with K_SNR.
-          s = typebuf.tb_noremap + typebuf.tb_off;
+          uint8_t *s = typebuf.tb_noremap + typebuf.tb_off;
           if (*s == RM_SCRIPT
               && (mp->m_keys[0] != K_SPECIAL
                   || mp->m_keys[1] != KS_EXTRA
@@ -2248,7 +2247,7 @@ static int handle_mapping(int *keylenp, bool *timedout, int *mapdepth)
 
       save_m_keys = vim_strsave(mp->m_keys);
       if (save_m_luaref == LUA_NOREF) {
-        save_m_str = vim_strsave(mp->m_str);
+        save_m_str = vim_strsave((char_u *)mp->m_str);
       }
       map_str = eval_map_expr(mp, NUL);
 
@@ -2280,7 +2279,7 @@ static int handle_mapping(int *keylenp, bool *timedout, int *mapdepth)
       vgetc_busy = save_vgetc_busy;
       may_garbage_collect = save_may_garbage_collect;
     } else {
-      map_str = mp->m_str;
+      map_str = (char_u *)mp->m_str;
     }
 
     // Insert the 'to' part in the typebuf.tb_buf.
@@ -2501,7 +2500,7 @@ static int vgetorpeek(bool advance)
                 // write char to script file(s)
                 gotchars(typebuf.tb_buf + typebuf.tb_off, 1);
               }
-              KeyNoremap = typebuf.tb_noremap[typebuf.tb_off];
+              KeyNoremap = (unsigned char)typebuf.tb_noremap[typebuf.tb_off];
               del_typebuf(1, 0);
             }
             break;  // got character, break the for loop
diff --git a/src/nvim/globals.h b/src/nvim/globals.h
index 67b113849c..37181d02bd 100644
--- a/src/nvim/globals.h
+++ b/src/nvim/globals.h
@@ -755,7 +755,7 @@ EXTERN int keep_help_flag INIT(= false);  // doing :ta from help file
 // When a string option is NULL (which only happens in out-of-memory
 // situations), it is set to empty_option, to avoid having to check for NULL
 // everywhere.
-EXTERN char_u *empty_option INIT(= (char_u *)"");
+EXTERN char *empty_option INIT(= "");
 
 EXTERN bool redir_off INIT(= false);        // no redirection for a moment
 EXTERN FILE *redir_fd INIT(= NULL);         // message redirection file
diff --git a/src/nvim/indent.c b/src/nvim/indent.c
index f18a6d7b32..12fad371ae 100644
--- a/src/nvim/indent.c
+++ b/src/nvim/indent.c
@@ -710,7 +710,7 @@ int get_number_indent(linenr_T lnum)
   if ((State & MODE_INSERT) || has_format_option(FO_Q_COMS)) {
     lead_len = get_leader_len((char *)ml_get(lnum), NULL, false, true);
   }
-  regmatch.regprog = vim_regcomp((char *)curbuf->b_p_flp, RE_MAGIC);
+  regmatch.regprog = vim_regcomp(curbuf->b_p_flp, RE_MAGIC);
 
   if (regmatch.regprog != NULL) {
     regmatch.rm_ic = false;
@@ -770,7 +770,7 @@ int get_breakindent_win(win_T *wp, char_u *line)
   // add additional indent for numbered lists
   if (wp->w_briopt_list != 0) {
     regmatch_T regmatch = {
-      .regprog = vim_regcomp((char *)curbuf->b_p_flp,
+      .regprog = vim_regcomp(curbuf->b_p_flp,
                              RE_MAGIC + RE_STRING + RE_AUTO + RE_STRICT),
     };
 
@@ -855,7 +855,7 @@ int get_expr_indent(void)
 
   // Need to make a copy, the 'indentexpr' option could be changed while
   // evaluating it.
-  char_u *inde_copy = vim_strsave(curbuf->b_p_inde);
+  char_u *inde_copy = vim_strsave((char_u *)curbuf->b_p_inde);
   indent = (int)eval_to_number((char *)inde_copy);
   xfree(inde_copy);
 
@@ -1077,7 +1077,7 @@ static int lisp_match(char_u *p)
 {
   char_u buf[LSIZE];
   int len;
-  char *word = (char *)(*curbuf->b_p_lw != NUL ? curbuf->b_p_lw : p_lispwords);
+  char *word = (char *)(*curbuf->b_p_lw != NUL ? (char_u *)curbuf->b_p_lw : p_lispwords);
 
   while (*word != NUL) {
     (void)copy_option_part(&word, (char *)buf, LSIZE, ",");
diff --git a/src/nvim/indent_c.c b/src/nvim/indent_c.c
index fe8c235cc1..df337125ca 100644
--- a/src/nvim/indent_c.c
+++ b/src/nvim/indent_c.c
@@ -223,7 +223,7 @@ bool cin_is_cinword(const char_u *line)
   char_u *cinw_buf = xmalloc(cinw_len);
   line = (char_u *)skipwhite((char *)line);
 
-  for (char *cinw = (char *)curbuf->b_p_cinw; *cinw;) {
+  for (char *cinw = curbuf->b_p_cinw; *cinw;) {
     size_t len = copy_option_part(&cinw, (char *)cinw_buf, cinw_len, ",");
     if (STRNCMP(line, cinw_buf, len) == 0
         && (!vim_iswordc(line[len]) || !vim_iswordc(line[len - 1]))) {
@@ -519,7 +519,7 @@ bool cin_isscopedecl(const char_u *p)
 
   bool found = false;
 
-  for (char *cinsd = (char *)curbuf->b_p_cinsd; *cinsd;) {
+  for (char *cinsd = curbuf->b_p_cinsd; *cinsd;) {
     const size_t len = copy_option_part(&cinsd, (char *)cinsd_buf, cinsd_len, ",");
     if (STRNCMP(s, cinsd_buf, len) == 0) {
       const char_u *skip = cin_skipcomment(s + len);
@@ -1740,7 +1740,7 @@ void parse_cino(buf_T *buf)
   // Handle C #pragma directives
   buf->b_ind_pragma = 0;
 
-  for (p = (char *)buf->b_p_cino; *p;) {
+  for (p = buf->b_p_cino; *p;) {
     l = p++;
     if (*p == '-') {
       p++;
@@ -2063,7 +2063,7 @@ int get_c_indent(void)
     *lead_start = NUL;
     *lead_middle = NUL;
 
-    p = (char *)curbuf->b_p_com;
+    p = curbuf->b_p_com;
     while (*p != NUL) {
       int align = 0;
       int off = 0;
diff --git a/src/nvim/insexpand.c b/src/nvim/insexpand.c
index c92183dc2a..a3b5e3df5c 100644
--- a/src/nvim/insexpand.c
+++ b/src/nvim/insexpand.c
@@ -901,7 +901,7 @@ static void ins_compl_longest_match(compl_T *match)
 
     had_match = (curwin->w_cursor.col > compl_col);
     ins_compl_delete();
-    ins_bytes(compl_leader + get_compl_len());
+    ins_bytes((char *)compl_leader + get_compl_len());
     ins_redraw(false);
 
     // When the match isn't there (to avoid matching itself) remove it
@@ -935,7 +935,7 @@ static void ins_compl_longest_match(compl_T *match)
     *p = NUL;
     had_match = (curwin->w_cursor.col > compl_col);
     ins_compl_delete();
-    ins_bytes(compl_leader + get_compl_len());
+    ins_bytes((char *)compl_leader + get_compl_len());
     ins_redraw(false);
 
     // When the match isn't there (to avoid matching itself) remove it
@@ -1677,7 +1677,7 @@ static void ins_compl_new_leader(void)
 {
   ins_compl_del_pum();
   ins_compl_delete();
-  ins_bytes(compl_leader + get_compl_len());
+  ins_bytes((char *)compl_leader + get_compl_len());
   compl_used_match = false;
 
   if (compl_started) {
@@ -2224,11 +2224,11 @@ static char_u *get_complete_funcname(int type)
 {
   switch (type) {
   case CTRL_X_FUNCTION:
-    return curbuf->b_p_cfu;
+    return (char_u *)curbuf->b_p_cfu;
   case CTRL_X_OMNI:
-    return curbuf->b_p_ofu;
+    return (char_u *)curbuf->b_p_ofu;
   case CTRL_X_THESAURUS:
-    return *curbuf->b_p_tsrfu == NUL ? p_tsrfu : curbuf->b_p_tsrfu;
+    return *curbuf->b_p_tsrfu == NUL ? p_tsrfu : (char_u *)curbuf->b_p_tsrfu;
   default:
     return (char_u *)"";
   }
@@ -2823,8 +2823,8 @@ static void get_next_dict_tsr_completion(int compl_type, char_u *dict, int dict_
   } else {
     ins_compl_dictionaries(dict != NULL ? dict
                            : (compl_type == CTRL_X_THESAURUS
-                              ? (*curbuf->b_p_tsr == NUL ? p_tsr : curbuf->b_p_tsr)
-                              : (*curbuf->b_p_dict == NUL ? p_dict : curbuf->b_p_dict)),
+                              ? (*curbuf->b_p_tsr == NUL ? p_tsr : (char_u *)curbuf->b_p_tsr)
+                              : (*curbuf->b_p_dict == NUL ? p_dict : (char_u *)curbuf->b_p_dict)),
                            (char_u *)compl_pattern,
                            dict != NULL ? dict_f : 0,
                            compl_type == CTRL_X_THESAURUS);
@@ -3174,7 +3174,7 @@ static int ins_compl_get_exp(pos_T *ini)
     }
     st.found_all = false;
     st.ins_buf = curbuf;
-    st.e_cpt = (compl_cont_status & CONT_LOCAL) ? "." : (char *)curbuf->b_p_cpt;
+    st.e_cpt = (compl_cont_status & CONT_LOCAL) ? "." : curbuf->b_p_cpt;
     st.last_match_pos = st.first_match_pos = *ini;
   } else if (st.ins_buf != curbuf && !buf_valid(st.ins_buf)) {
     st.ins_buf = curbuf;  // In case the buffer was wiped out.
@@ -3319,7 +3319,7 @@ void ins_compl_delete(void)
 /// "in_compl_func" is true when called from complete_check().
 void ins_compl_insert(bool in_compl_func)
 {
-  ins_bytes(compl_shown_match->cp_str + get_compl_len());
+  ins_bytes((char *)compl_shown_match->cp_str + get_compl_len());
   compl_used_match = !match_at_original_text(compl_shown_match);
 
   dict_T *dict = ins_compl_dict_alloc(compl_shown_match);
@@ -3511,13 +3511,13 @@ static int ins_compl_next(bool allow_get_expansion, int count, bool insert_match
 
   // Insert the text of the new completion, or the compl_leader.
   if (compl_no_insert && !started) {
-    ins_bytes(compl_orig_text + get_compl_len());
+    ins_bytes((char *)compl_orig_text + get_compl_len());
     compl_used_match = false;
   } else if (insert_match) {
     if (!compl_get_longest || compl_used_match) {
       ins_compl_insert(in_compl_func);
     } else {
-      ins_bytes(compl_leader + get_compl_len());
+      ins_bytes((char *)compl_leader + get_compl_len());
     }
   } else {
     compl_used_match = false;
@@ -4079,9 +4079,9 @@ static int ins_compl_start(void)
     edit_submode_pre = (char_u *)_(" Adding");
     if (ctrl_x_mode_line_or_eval()) {
       // Insert a new line, keep indentation but ignore 'comments'.
-      char_u *old = curbuf->b_p_com;
+      char *old = curbuf->b_p_com;
 
-      curbuf->b_p_com = (char_u *)"";
+      curbuf->b_p_com = "";
       compl_startpos.lnum = curwin->w_cursor.lnum;
       compl_startpos.col = compl_col;
       ins_eol('\r');
diff --git a/src/nvim/lua/executor.c b/src/nvim/lua/executor.c
index 38bc187f4f..39585ac182 100644
--- a/src/nvim/lua/executor.c
+++ b/src/nvim/lua/executor.c
@@ -990,7 +990,7 @@ int nlua_in_fast_event(lua_State *lstate)
 
 static bool viml_func_is_fast(const char *name)
 {
-  const EvalFuncDef *const fdef = find_internal_func((const char *)name);
+  const EvalFuncDef *const fdef = find_internal_func(name);
   if (fdef) {
     return fdef->fast;
   }
diff --git a/src/nvim/mapping.c b/src/nvim/mapping.c
index 9da7e9a947..f7f1de13c4 100644
--- a/src/nvim/mapping.c
+++ b/src/nvim/mapping.c
@@ -150,7 +150,7 @@ static void showmap(mapblock_T *mp, bool local)
 {
   size_t len = 1;
 
-  if (message_filtered(mp->m_keys) && message_filtered(mp->m_str)
+  if (message_filtered(mp->m_keys) && message_filtered((char_u *)mp->m_str)
       && (mp->m_desc == NULL || message_filtered((char_u *)mp->m_desc))) {
     return;
   }
@@ -203,7 +203,7 @@ static void showmap(mapblock_T *mp, bool local)
   } else if (mp->m_str[0] == NUL) {
     msg_puts_attr("<Nop>", HL_ATTR(HLF_8));
   } else {
-    msg_outtrans_special(mp->m_str, false, 0);
+    msg_outtrans_special((char_u *)mp->m_str, false, 0);
   }
 
   if (mp->m_desc != NULL) {
@@ -449,8 +449,8 @@ static void map_add(buf_T *buf, mapblock_T **map_table, mapblock_T **abbr_table,
   }
 
   mp->m_keys = vim_strsave(keys);
-  mp->m_str = args->rhs;
-  mp->m_orig_str = args->orig_rhs;
+  mp->m_str = (char *)args->rhs;
+  mp->m_orig_str = (char *)args->orig_rhs;
   mp->m_luaref = args->rhs_lua;
   if (!simplified) {
     args->rhs = NULL;
@@ -704,7 +704,7 @@ static int buf_do_map(int maptype, MapArguments *args, int mode, bool is_abbrev,
           } else {                          // do we have a match?
             if (round) {              // second round: Try unmap "rhs" string
               n = (int)STRLEN(mp->m_str);
-              p = mp->m_str;
+              p = (char_u *)mp->m_str;
             } else {
               n = mp->m_keylen;
               p = mp->m_keys;
@@ -761,8 +761,8 @@ static int buf_do_map(int maptype, MapArguments *args, int mode, bool is_abbrev,
                     XFREE_CLEAR(mp->m_str);
                     XFREE_CLEAR(mp->m_orig_str);
                   }
-                  mp->m_str = args->rhs;
-                  mp->m_orig_str = args->orig_rhs;
+                  mp->m_str = (char *)args->rhs;
+                  mp->m_orig_str = (char *)args->orig_rhs;
                   mp->m_luaref = args->rhs_lua;
                   if (!keyround1_simplified) {
                     args->rhs = NULL;
@@ -1113,7 +1113,7 @@ int map_to_exists_mode(const char *const rhs, const int mode, const bool abbr)
         mp = maphash[hash];
       }
       for (; mp; mp = mp->m_next) {
-        if ((mp->m_mode & mode) && strstr((char *)mp->m_str, rhs) != NULL) {
+        if ((mp->m_mode & mode) && strstr(mp->m_str, rhs) != NULL) {
           return true;
         }
       }
@@ -1506,7 +1506,7 @@ bool check_abbr(int c, char_u *ptr, int col, int mincol)
       if (mp->m_expr) {
         s = eval_map_expr(mp, c);
       } else {
-        s = mp->m_str;
+        s = (char_u *)mp->m_str;
       }
       if (s != NULL) {
         // insert the to string
@@ -1542,7 +1542,7 @@ char_u *eval_map_expr(mapblock_T *mp, int c)
   // Remove escaping of K_SPECIAL, because "str" is in a format to be used as
   // typeahead.
   if (mp->m_luaref == LUA_NOREF) {
-    expr = vim_strsave(mp->m_str);
+    expr = vim_strsave((char_u *)mp->m_str);
     vim_unescape_ks(expr);
   }
 
@@ -1639,7 +1639,7 @@ int makemap(FILE *fd, buf_T *buf)
         if (mp->m_luaref != LUA_NOREF) {
           continue;
         }
-        for (p = mp->m_str; *p != NUL; p++) {
+        for (p = (char_u *)mp->m_str; *p != NUL; p++) {
           if (p[0] == K_SPECIAL && p[1] == KS_EXTRA
               && p[2] == KE_SNR) {
             break;
@@ -1785,7 +1785,7 @@ int makemap(FILE *fd, buf_T *buf)
           if (putc(' ', fd) < 0
               || put_escstr(fd, mp->m_keys, 0) == FAIL
               || putc(' ', fd) < 0
-              || put_escstr(fd, mp->m_str, 1) == FAIL
+              || put_escstr(fd, (char_u *)mp->m_str, 1) == FAIL
               || put_eol(fd) < 0) {
             return FAIL;
           }
@@ -1956,7 +1956,7 @@ char_u *check_map(char_u *keys, int mode, int exact, int ign_mod, int abbr, mapb
               *local_ptr = local;
             }
             *rhs_lua = mp->m_luaref;
-            return mp->m_luaref == LUA_NOREF ? mp->m_str : NULL;
+            return mp->m_luaref == LUA_NOREF ? (char_u *)mp->m_str : NULL;
           }
         }
       }
diff --git a/src/nvim/mbyte.c b/src/nvim/mbyte.c
index f9d8422481..83044f209a 100644
--- a/src/nvim/mbyte.c
+++ b/src/nvim/mbyte.c
@@ -1932,11 +1932,11 @@ void utf_find_illegal(void)
   char_u *tofree = NULL;
 
   vimconv.vc_type = CONV_NONE;
-  if (enc_canon_props(curbuf->b_p_fenc) & ENC_8BIT) {
+  if (enc_canon_props((char_u *)curbuf->b_p_fenc) & ENC_8BIT) {
     // 'encoding' is "utf-8" but we are editing a 8-bit encoded file,
     // possibly a utf-8 file with illegal bytes.  Setup for conversion
     // from utf-8 to 'fileencoding'.
-    convert_setup(&vimconv, p_enc, curbuf->b_p_fenc);
+    convert_setup(&vimconv, p_enc, (char_u *)curbuf->b_p_fenc);
   }
 
   curwin->w_cursor.coladd = 0;
diff --git a/src/nvim/memline.c b/src/nvim/memline.c
index 980d6908f9..318bd64d88 100644
--- a/src/nvim/memline.c
+++ b/src/nvim/memline.c
@@ -721,7 +721,7 @@ static void add_b0_fenc(ZERO_BL *b0p, buf_T *buf)
     b0p->b0_flags &= (uint8_t) ~B0_HAS_FENC;
   } else {
     memmove((char *)b0p->b0_fname + size - n,
-            (char *)buf->b_p_fenc, (size_t)n);
+            buf->b_p_fenc, (size_t)n);
     *(b0p->b0_fname + size - n - 1) = NUL;
     b0p->b0_flags |= B0_HAS_FENC;
   }
diff --git a/src/nvim/msgpack_rpc/server.c b/src/nvim/msgpack_rpc/server.c
index b252f0998e..532e684f93 100644
--- a/src/nvim/msgpack_rpc/server.c
+++ b/src/nvim/msgpack_rpc/server.c
@@ -216,7 +216,7 @@ bool server_stop(char *endpoint)
   watchers.ga_len--;
 
   // Bump v:servername to the next available server, if any.
-  if (strequal(addr, (char *)get_vim_var_str(VV_SEND_SERVER))) {
+  if (strequal(addr, get_vim_var_str(VV_SEND_SERVER))) {
     set_vservername(&watchers);
   }
 
diff --git a/src/nvim/normal.c b/src/nvim/normal.c
index 75900b735b..1bd780be0f 100644
--- a/src/nvim/normal.c
+++ b/src/nvim/normal.c
@@ -2653,10 +2653,10 @@ void clear_showcmd(void)
 
     if (VIsual_mode == Ctrl_V) {
       char_u *const saved_sbr = p_sbr;
-      char_u *const saved_w_sbr = curwin->w_p_sbr;
+      char *const saved_w_sbr = curwin->w_p_sbr;
 
       // Make 'sbr' empty for a moment to get the correct size.
-      p_sbr = empty_option;
+      p_sbr = (char_u *)empty_option;
       curwin->w_p_sbr = empty_option;
       getvcols(curwin, &curwin->w_cursor, &VIsual, &leftcol, &rightcol);
       p_sbr = saved_sbr;
@@ -4275,7 +4275,7 @@ static void nv_ident(cmdarg_T *cap)
   // Allocate buffer to put the command in.  Inserting backslashes can
   // double the length of the word.  p_kp / curbuf->b_p_kp could be added
   // and some numbers.
-  char_u *kp = *curbuf->b_p_kp == NUL ? p_kp : curbuf->b_p_kp;  // 'keywordprg'
+  char_u *kp = *curbuf->b_p_kp == NUL ? p_kp : (char_u *)curbuf->b_p_kp;  // 'keywordprg'
   assert(*kp != NUL);  // option.c:do_set() should default to ":help" if empty.
   bool kp_ex = (*kp == ':');  // 'keywordprg' is an ex command
   bool kp_help = (STRCMP(kp, ":he") == 0 || STRCMP(kp, ":help") == 0);
@@ -7075,8 +7075,8 @@ static void nv_object(cmdarg_T *cap)
     include = true;         // "ax" = an object: include white space
   }
   // Make sure (), [], {} and <> are in 'matchpairs'
-  mps_save = curbuf->b_p_mps;
-  curbuf->b_p_mps = (char_u *)"(:),{:},[:],<:>";
+  mps_save = (char_u *)curbuf->b_p_mps;
+  curbuf->b_p_mps = "(:),{:},[:],<:>";
 
   switch (cap->nchar) {
   case 'w':       // "aw" = a word
@@ -7130,7 +7130,7 @@ static void nv_object(cmdarg_T *cap)
     break;
   }
 
-  curbuf->b_p_mps = mps_save;
+  curbuf->b_p_mps = (char *)mps_save;
   if (!flag) {
     clearopbeep(cap->oap);
   }
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 1f6b154eed..b30538a9dc 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -4385,23 +4385,20 @@ int fex_format(linenr_T lnum, long count, int c)
 {
   int use_sandbox = was_set_insecurely(curwin, "formatexpr", OPT_LOCAL);
   int r;
-  char_u *fex;
 
-  /*
-   * Set v:lnum to the first line number and v:count to the number of lines.
-   * Set v:char to the character to be inserted (can be NUL).
-   */
+  // Set v:lnum to the first line number and v:count to the number of lines.
+  // Set v:char to the character to be inserted (can be NUL).
   set_vim_var_nr(VV_LNUM, (varnumber_T)lnum);
   set_vim_var_nr(VV_COUNT, (varnumber_T)count);
   set_vim_var_char(c);
 
   // Make a copy, the option could be changed while calling it.
-  fex = vim_strsave(curbuf->b_p_fex);
+  char *fex = xstrdup(curbuf->b_p_fex);
   // Evaluate the function.
   if (use_sandbox) {
     sandbox++;
   }
-  r = (int)eval_to_number((char *)fex);
+  r = (int)eval_to_number(fex);
   if (use_sandbox) {
     sandbox--;
   }
@@ -5008,12 +5005,12 @@ int do_addsub(int op_type, pos_T *pos, int length, linenr_T Prenum1)
   pos_T endpos;
   colnr_T save_coladd = 0;
 
-  const bool do_hex = vim_strchr((char *)curbuf->b_p_nf, 'x') != NULL;    // "heX"
-  const bool do_oct = vim_strchr((char *)curbuf->b_p_nf, 'o') != NULL;    // "Octal"
-  const bool do_bin = vim_strchr((char *)curbuf->b_p_nf, 'b') != NULL;    // "Bin"
-  const bool do_alpha = vim_strchr((char *)curbuf->b_p_nf, 'p') != NULL;  // "alPha"
+  const bool do_hex = vim_strchr(curbuf->b_p_nf, 'x') != NULL;    // "heX"
+  const bool do_oct = vim_strchr(curbuf->b_p_nf, 'o') != NULL;    // "Octal"
+  const bool do_bin = vim_strchr(curbuf->b_p_nf, 'b') != NULL;    // "Bin"
+  const bool do_alpha = vim_strchr(curbuf->b_p_nf, 'p') != NULL;  // "alPha"
   // "Unsigned"
-  const bool do_unsigned = vim_strchr((char *)curbuf->b_p_nf, 'u') != NULL;
+  const bool do_unsigned = vim_strchr(curbuf->b_p_nf, 'u') != NULL;
 
   if (virtual_active()) {
     save_coladd = pos->coladd;
@@ -5886,10 +5883,10 @@ void cursor_pos_info(dict_T *dict)
 
       if (l_VIsual_mode == Ctrl_V) {
         char_u *const saved_sbr = p_sbr;
-        char_u *const saved_w_sbr = curwin->w_p_sbr;
+        char *const saved_w_sbr = curwin->w_p_sbr;
 
         // Make 'sbr' empty for a moment to get the correct size.
-        p_sbr = empty_option;
+        p_sbr = (char_u *)empty_option;
         curwin->w_p_sbr = empty_option;
         oparg.is_VIsual = true;
         oparg.motion_type = kMTBlockWise;
diff --git a/src/nvim/option.c b/src/nvim/option.c
index b1d5be8cb7..b2525b73a0 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -464,7 +464,7 @@ static void set_option_default(int opt_idx, int opt_flags)
                                  (char *)options[opt_idx].def_val, opt_flags, 0);
       } else {
         if ((opt_flags & OPT_FREE) && (flags & P_ALLOCED)) {
-          free_string_option(*(char_u **)(varp));
+          free_string_option(*(char **)(varp));
         }
         *(char_u **)varp = options[opt_idx].def_val;
         options[opt_idx].flags &= ~P_ALLOCED;
@@ -603,14 +603,14 @@ void free_all_options(void)
     if (options[i].indir == PV_NONE) {
       // global option: free value and default value.
       if ((options[i].flags & P_ALLOCED) && options[i].var != NULL) {
-        free_string_option(*(char_u **)options[i].var);
+        free_string_option(*(char **)options[i].var);
       }
       if (options[i].flags & P_DEF_ALLOCED) {
-        free_string_option(options[i].def_val);
+        free_string_option((char *)options[i].def_val);
       }
     } else if (options[i].var != VAR_WIN && (options[i].flags & P_STRING)) {
       // buffer-local option: free global value
-      clear_string_option((char_u **)options[i].var);
+      clear_string_option((char **)options[i].var);
     }
   }
   free_operatorfunc_option();
@@ -730,7 +730,7 @@ void set_helplang_default(const char *lang)
   int idx = findoption("hlg");
   if (idx >= 0 && !(options[idx].flags & P_WAS_SET)) {
     if (options[idx].flags & P_ALLOCED) {
-      free_string_option(p_hlg);
+      free_string_option((char *)p_hlg);
     }
     p_hlg = (char_u *)xmemdupz(lang, lang_len);
     // zh_CN becomes "cn", zh_TW becomes "tw".
@@ -1185,7 +1185,7 @@ int do_set(char *arg, int opt_flags)
               // A global-local string option might have an empty
               // option as value to indicate that the global
               // value should be used.
-              if (((int)options[opt_idx].indir & PV_BOTH) && origval_l == empty_option) {
+              if (((int)options[opt_idx].indir & PV_BOTH) && origval_l == (char_u *)empty_option) {
                 origval_l = origval_g;
               }
             }
@@ -1205,7 +1205,7 @@ int do_set(char *arg, int opt_flags)
               // required when an environment variable was set
               // later
               if (newval == NULL) {
-                newval = empty_option;
+                newval = (char_u *)empty_option;
               } else if (!(options[opt_idx].flags & P_NO_DEF_EXP)) {
                 s = option_expand(opt_idx, newval);
                 if (s == NULL) {
@@ -1233,7 +1233,7 @@ int do_set(char *arg, int opt_flags)
                 i = getdigits_int((char **)varp, true, 0);
                 switch (i) {
                 case 0:
-                  *(char_u **)varp = empty_option;
+                  *(char **)varp = empty_option;
                   break;
                 case 1:
                   *(char_u **)varp = vim_strsave((char_u *)"indent,eol");
@@ -1797,17 +1797,17 @@ static void didset_options2(void)
   highlight_changed();
 
   // Parse default for 'fillchars'.
-  (void)set_chars_option(curwin, &curwin->w_p_fcs, true);
+  (void)set_chars_option(curwin, (char_u **)&curwin->w_p_fcs, true);
 
   // Parse default for 'listchars'.
-  (void)set_chars_option(curwin, &curwin->w_p_lcs, true);
+  (void)set_chars_option(curwin, (char_u **)&curwin->w_p_lcs, true);
 
   // Parse default for 'wildmode'.
   check_opt_wim();
   xfree(curbuf->b_p_vsts_array);
-  (void)tabstop_set(curbuf->b_p_vsts, &curbuf->b_p_vsts_array);
+  (void)tabstop_set((char_u *)curbuf->b_p_vsts, &curbuf->b_p_vsts_array);
   xfree(curbuf->b_p_vts_array);
-  (void)tabstop_set(curbuf->b_p_vts,  &curbuf->b_p_vts_array);
+  (void)tabstop_set((char_u *)curbuf->b_p_vts,  &curbuf->b_p_vts_array);
 }
 
 /// Check for string options that are NULL (normally only termcap options).
@@ -1817,7 +1817,7 @@ void check_options(void)
 
   for (opt_idx = 0; options[opt_idx].fullname != NULL; opt_idx++) {
     if ((options[opt_idx].flags & P_STRING) && options[opt_idx].var != NULL) {
-      check_string_option((char_u **)get_varp(&(options[opt_idx])));
+      check_string_option((char **)get_varp(&(options[opt_idx])));
     }
   }
 }
@@ -3597,12 +3597,12 @@ int makeset(FILE *fd, int opt_flags, int local_only)
 /// 'sessionoptions' or 'viewoptions' contains "folds" but not "options".
 int makefoldset(FILE *fd)
 {
-  if (put_setstring(fd, "setlocal", "fdm", &curwin->w_p_fdm, 0) == FAIL
-      || put_setstring(fd, "setlocal", "fde", &curwin->w_p_fde, 0)
+  if (put_setstring(fd, "setlocal", "fdm", (char_u **)&curwin->w_p_fdm, 0) == FAIL
+      || put_setstring(fd, "setlocal", "fde", (char_u **)&curwin->w_p_fde, 0)
       == FAIL
-      || put_setstring(fd, "setlocal", "fmr", &curwin->w_p_fmr, 0)
+      || put_setstring(fd, "setlocal", "fmr", (char_u **)&curwin->w_p_fmr, 0)
       == FAIL
-      || put_setstring(fd, "setlocal", "fdi", &curwin->w_p_fdi, 0)
+      || put_setstring(fd, "setlocal", "fdi", (char_u **)&curwin->w_p_fdi, 0)
       == FAIL
       || put_setnum(fd, "setlocal", "fdl", &curwin->w_p_fdl) == FAIL
       || put_setnum(fd, "setlocal", "fml", &curwin->w_p_fml) == FAIL
@@ -3803,7 +3803,7 @@ void unset_global_local_option(char *name, void *from)
     clear_string_option(&((win_T *)from)->w_p_stl);
     break;
   case PV_WBR:
-    clear_string_option((char_u **)&((win_T *)from)->w_p_wbr);
+    clear_string_option(&((win_T *)from)->w_p_wbr);
     break;
   case PV_UL:
     buf->b_p_ul = NO_LOCAL_UNDOLEVEL;
@@ -3816,12 +3816,12 @@ void unset_global_local_option(char *name, void *from)
     break;
   case PV_LCS:
     clear_string_option(&((win_T *)from)->w_p_lcs);
-    set_chars_option((win_T *)from, &((win_T *)from)->w_p_lcs, true);
+    set_chars_option((win_T *)from, (char_u **)&((win_T *)from)->w_p_lcs, true);
     redraw_later((win_T *)from, UPD_NOT_VALID);
     break;
   case PV_FCS:
     clear_string_option(&((win_T *)from)->w_p_fcs);
-    set_chars_option((win_T *)from, &((win_T *)from)->w_p_fcs, true);
+    set_chars_option((win_T *)from, (char_u **)&((win_T *)from)->w_p_fcs, true);
     redraw_later((win_T *)from, UPD_NOT_VALID);
     break;
   case PV_VE:
@@ -4238,7 +4238,7 @@ char_u *get_equalprg(void)
   if (*curbuf->b_p_ep == NUL) {
     return p_ep;
   }
-  return curbuf->b_p_ep;
+  return (char_u *)curbuf->b_p_ep;
 }
 
 /// Copy options from one window to another.
@@ -4260,19 +4260,19 @@ void copy_winopt(winopt_T *from, winopt_T *to)
   to->wo_list = from->wo_list;
   to->wo_nu = from->wo_nu;
   to->wo_rnu = from->wo_rnu;
-  to->wo_ve = vim_strsave(from->wo_ve);
+  to->wo_ve = xstrdup(from->wo_ve);
   to->wo_ve_flags = from->wo_ve_flags;
   to->wo_nuw = from->wo_nuw;
   to->wo_rl  = from->wo_rl;
-  to->wo_rlc = vim_strsave(from->wo_rlc);
-  to->wo_sbr = vim_strsave(from->wo_sbr);
-  to->wo_stl = vim_strsave(from->wo_stl);
+  to->wo_rlc = xstrdup(from->wo_rlc);
+  to->wo_sbr = xstrdup(from->wo_sbr);
+  to->wo_stl = xstrdup(from->wo_stl);
   to->wo_wbr = xstrdup(from->wo_wbr);
   to->wo_wrap = from->wo_wrap;
   to->wo_wrap_save = from->wo_wrap_save;
   to->wo_lbr = from->wo_lbr;
   to->wo_bri = from->wo_bri;
-  to->wo_briopt = vim_strsave(from->wo_briopt);
+  to->wo_briopt = xstrdup(from->wo_briopt);
   to->wo_scb = from->wo_scb;
   to->wo_scb_save = from->wo_scb_save;
   to->wo_crb = from->wo_crb;
@@ -4280,32 +4280,30 @@ void copy_winopt(winopt_T *from, winopt_T *to)
   to->wo_spell = from->wo_spell;
   to->wo_cuc = from->wo_cuc;
   to->wo_cul = from->wo_cul;
-  to->wo_culopt = vim_strsave(from->wo_culopt);
-  to->wo_cc = vim_strsave(from->wo_cc);
+  to->wo_culopt = xstrdup(from->wo_culopt);
+  to->wo_cc = xstrdup(from->wo_cc);
   to->wo_diff = from->wo_diff;
   to->wo_diff_saved = from->wo_diff_saved;
-  to->wo_cocu = vim_strsave(from->wo_cocu);
+  to->wo_cocu = xstrdup(from->wo_cocu);
   to->wo_cole = from->wo_cole;
-  to->wo_fdc = vim_strsave(from->wo_fdc);
-  to->wo_fdc_save = from->wo_diff_saved
-                    ? vim_strsave(from->wo_fdc_save) : empty_option;
+  to->wo_fdc = xstrdup(from->wo_fdc);
+  to->wo_fdc_save = from->wo_diff_saved ? xstrdup(from->wo_fdc_save) : empty_option;
   to->wo_fen = from->wo_fen;
   to->wo_fen_save = from->wo_fen_save;
-  to->wo_fdi = vim_strsave(from->wo_fdi);
+  to->wo_fdi = xstrdup(from->wo_fdi);
   to->wo_fml = from->wo_fml;
   to->wo_fdl = from->wo_fdl;
   to->wo_fdl_save = from->wo_fdl_save;
-  to->wo_fdm = vim_strsave(from->wo_fdm);
-  to->wo_fdm_save = from->wo_diff_saved
-                    ? vim_strsave(from->wo_fdm_save) : empty_option;
+  to->wo_fdm = xstrdup(from->wo_fdm);
+  to->wo_fdm_save = from->wo_diff_saved ? xstrdup(from->wo_fdm_save) : empty_option;
   to->wo_fdn = from->wo_fdn;
-  to->wo_fde = vim_strsave(from->wo_fde);
-  to->wo_fdt = vim_strsave(from->wo_fdt);
-  to->wo_fmr = vim_strsave(from->wo_fmr);
-  to->wo_scl = vim_strsave(from->wo_scl);
-  to->wo_winhl = vim_strsave(from->wo_winhl);
-  to->wo_fcs = vim_strsave(from->wo_fcs);
-  to->wo_lcs = vim_strsave(from->wo_lcs);
+  to->wo_fde = xstrdup(from->wo_fde);
+  to->wo_fdt = xstrdup(from->wo_fdt);
+  to->wo_fmr = xstrdup(from->wo_fmr);
+  to->wo_scl = xstrdup(from->wo_scl);
+  to->wo_winhl = xstrdup(from->wo_winhl);
+  to->wo_fcs = xstrdup(from->wo_fcs);
+  to->wo_lcs = xstrdup(from->wo_lcs);
   to->wo_winbl = from->wo_winbl;
 
   // Copy the script context so that we know were the value was last set.
@@ -4343,7 +4341,7 @@ static void check_winopt(winopt_T *wop)
   check_string_option(&wop->wo_fcs);
   check_string_option(&wop->wo_lcs);
   check_string_option(&wop->wo_ve);
-  check_string_option((char_u **)&wop->wo_wbr);
+  check_string_option(&wop->wo_wbr);
 }
 
 /// Free the allocated memory inside a winopt_T.
@@ -4369,7 +4367,7 @@ void clear_winopt(winopt_T *wop)
   clear_string_option(&wop->wo_fcs);
   clear_string_option(&wop->wo_lcs);
   clear_string_option(&wop->wo_ve);
-  clear_string_option((char_u **)&wop->wo_wbr);
+  clear_string_option(&wop->wo_wbr);
 }
 
 void didset_window_options(win_T *wp, bool valid_cursor)
@@ -4377,8 +4375,8 @@ void didset_window_options(win_T *wp, bool valid_cursor)
   check_colorcolumn(wp);
   briopt_check(wp);
   fill_culopt_flags(NULL, wp);
-  set_chars_option(wp, &wp->w_p_fcs, true);
-  set_chars_option(wp, &wp->w_p_lcs, true);
+  set_chars_option(wp, (char_u **)&wp->w_p_fcs, true);
+  set_chars_option(wp, (char_u **)&wp->w_p_lcs, true);
   parse_winhl_opt(wp);  // sets w_hl_needs_update also for w_p_winbl
   check_blending(wp);
   set_winbar_win(wp, false, valid_cursor);
@@ -4451,7 +4449,7 @@ void buf_copy_options(buf_T *buf, int flags)
       // (jumping back to a help file with CTRL-T or CTRL-O)
       dont_do_help = ((flags & BCO_NOHELP) && buf->b_help) || buf->b_p_initialized;
       if (dont_do_help) {               // don't free b_p_isk
-        save_p_isk = buf->b_p_isk;
+        save_p_isk = (char_u *)buf->b_p_isk;
         buf->b_p_isk = NULL;
       }
       // Always free the allocated strings.  If not already initialized,
@@ -4459,19 +4457,19 @@ void buf_copy_options(buf_T *buf, int flags)
       if (!buf->b_p_initialized) {
         free_buf_options(buf, true);
         buf->b_p_ro = false;                    // don't copy readonly
-        buf->b_p_fenc = vim_strsave(p_fenc);
+        buf->b_p_fenc = (char *)vim_strsave(p_fenc);
         switch (*p_ffs) {
         case 'm':
-          buf->b_p_ff = vim_strsave((char_u *)FF_MAC);
+          buf->b_p_ff = xstrdup(FF_MAC);
           break;
         case 'd':
-          buf->b_p_ff = vim_strsave((char_u *)FF_DOS);
+          buf->b_p_ff = xstrdup(FF_DOS);
           break;
         case 'u':
-          buf->b_p_ff = vim_strsave((char_u *)FF_UNIX);
+          buf->b_p_ff = xstrdup(FF_UNIX);
           break;
         default:
-          buf->b_p_ff = vim_strsave(p_ff);
+          buf->b_p_ff = (char *)vim_strsave(p_ff);
           break;
         }
         buf->b_p_bh = empty_option;
@@ -4516,42 +4514,42 @@ void buf_copy_options(buf_T *buf, int flags)
         buf->b_p_swf = p_swf;
         COPY_OPT_SCTX(buf, BV_SWF);
       }
-      buf->b_p_cpt = vim_strsave(p_cpt);
+      buf->b_p_cpt = (char *)vim_strsave(p_cpt);
       COPY_OPT_SCTX(buf, BV_CPT);
 #ifdef BACKSLASH_IN_FILENAME
       buf->b_p_csl = vim_strsave(p_csl);
       COPY_OPT_SCTX(buf, BV_CSL);
 #endif
-      buf->b_p_cfu = vim_strsave(p_cfu);
+      buf->b_p_cfu = (char *)vim_strsave(p_cfu);
       COPY_OPT_SCTX(buf, BV_CFU);
-      buf->b_p_ofu = vim_strsave(p_ofu);
+      buf->b_p_ofu = (char *)vim_strsave(p_ofu);
       COPY_OPT_SCTX(buf, BV_OFU);
-      buf->b_p_tfu = vim_strsave(p_tfu);
+      buf->b_p_tfu = (char *)vim_strsave(p_tfu);
       COPY_OPT_SCTX(buf, BV_TFU);
       buf->b_p_sts = p_sts;
       COPY_OPT_SCTX(buf, BV_STS);
       buf->b_p_sts_nopaste = p_sts_nopaste;
-      buf->b_p_vsts = vim_strsave(p_vsts);
+      buf->b_p_vsts = (char *)vim_strsave(p_vsts);
       COPY_OPT_SCTX(buf, BV_VSTS);
-      if (p_vsts && p_vsts != empty_option) {
+      if (p_vsts && p_vsts != (char_u *)empty_option) {
         (void)tabstop_set(p_vsts, &buf->b_p_vsts_array);
       } else {
         buf->b_p_vsts_array = NULL;
       }
       buf->b_p_vsts_nopaste = p_vsts_nopaste
-                                ? vim_strsave(p_vsts_nopaste)
+                                ? (char *)vim_strsave(p_vsts_nopaste)
                                 : NULL;
-      buf->b_p_com = vim_strsave(p_com);
+      buf->b_p_com = (char *)vim_strsave(p_com);
       COPY_OPT_SCTX(buf, BV_COM);
-      buf->b_p_cms = vim_strsave(p_cms);
+      buf->b_p_cms = (char *)vim_strsave(p_cms);
       COPY_OPT_SCTX(buf, BV_CMS);
-      buf->b_p_fo = vim_strsave(p_fo);
+      buf->b_p_fo = (char *)vim_strsave(p_fo);
       COPY_OPT_SCTX(buf, BV_FO);
-      buf->b_p_flp = vim_strsave(p_flp);
+      buf->b_p_flp = (char *)vim_strsave(p_flp);
       COPY_OPT_SCTX(buf, BV_FLP);
-      buf->b_p_nf = vim_strsave(p_nf);
+      buf->b_p_nf = (char *)vim_strsave(p_nf);
       COPY_OPT_SCTX(buf, BV_NF);
-      buf->b_p_mps = vim_strsave(p_mps);
+      buf->b_p_mps = (char *)vim_strsave(p_mps);
       COPY_OPT_SCTX(buf, BV_MPS);
       buf->b_p_si = p_si;
       COPY_OPT_SCTX(buf, BV_SI);
@@ -4561,18 +4559,18 @@ void buf_copy_options(buf_T *buf, int flags)
       COPY_OPT_SCTX(buf, BV_CI);
       buf->b_p_cin = p_cin;
       COPY_OPT_SCTX(buf, BV_CIN);
-      buf->b_p_cink = vim_strsave(p_cink);
+      buf->b_p_cink = (char *)vim_strsave(p_cink);
       COPY_OPT_SCTX(buf, BV_CINK);
-      buf->b_p_cino = vim_strsave(p_cino);
+      buf->b_p_cino = (char *)vim_strsave(p_cino);
       COPY_OPT_SCTX(buf, BV_CINO);
-      buf->b_p_cinsd = vim_strsave(p_cinsd);
+      buf->b_p_cinsd = (char *)vim_strsave(p_cinsd);
       COPY_OPT_SCTX(buf, BV_CINSD);
 
       // Don't copy 'filetype', it must be detected
       buf->b_p_ft = empty_option;
       buf->b_p_pi = p_pi;
       COPY_OPT_SCTX(buf, BV_PI);
-      buf->b_p_cinw = vim_strsave(p_cinw);
+      buf->b_p_cinw = (char *)vim_strsave(p_cinw);
       COPY_OPT_SCTX(buf, BV_CINW);
       buf->b_p_lisp = p_lisp;
       COPY_OPT_SCTX(buf, BV_LISP);
@@ -4581,25 +4579,25 @@ void buf_copy_options(buf_T *buf, int flags)
       buf->b_p_smc = p_smc;
       COPY_OPT_SCTX(buf, BV_SMC);
       buf->b_s.b_syn_isk = empty_option;
-      buf->b_s.b_p_spc = vim_strsave(p_spc);
+      buf->b_s.b_p_spc = (char *)vim_strsave(p_spc);
       COPY_OPT_SCTX(buf, BV_SPC);
       (void)compile_cap_prog(&buf->b_s);
-      buf->b_s.b_p_spf = vim_strsave(p_spf);
+      buf->b_s.b_p_spf = (char *)vim_strsave(p_spf);
       COPY_OPT_SCTX(buf, BV_SPF);
-      buf->b_s.b_p_spl = vim_strsave(p_spl);
+      buf->b_s.b_p_spl = (char *)vim_strsave(p_spl);
       COPY_OPT_SCTX(buf, BV_SPL);
-      buf->b_s.b_p_spo = vim_strsave(p_spo);
+      buf->b_s.b_p_spo = (char *)vim_strsave(p_spo);
       COPY_OPT_SCTX(buf, BV_SPO);
-      buf->b_p_inde = vim_strsave(p_inde);
+      buf->b_p_inde = (char *)vim_strsave(p_inde);
       COPY_OPT_SCTX(buf, BV_INDE);
-      buf->b_p_indk = vim_strsave(p_indk);
+      buf->b_p_indk = (char *)vim_strsave(p_indk);
       COPY_OPT_SCTX(buf, BV_INDK);
       buf->b_p_fp = empty_option;
-      buf->b_p_fex = vim_strsave(p_fex);
+      buf->b_p_fex = (char *)vim_strsave(p_fex);
       COPY_OPT_SCTX(buf, BV_FEX);
-      buf->b_p_sua = vim_strsave(p_sua);
+      buf->b_p_sua = (char *)vim_strsave(p_sua);
       COPY_OPT_SCTX(buf, BV_SUA);
-      buf->b_p_keymap = vim_strsave(p_keymap);
+      buf->b_p_keymap = (char *)vim_strsave(p_keymap);
       COPY_OPT_SCTX(buf, BV_KMAP);
       buf->b_kmap_state |= KEYMAP_INIT;
       // This isn't really an option, but copying the langmap and IME
@@ -4626,12 +4624,12 @@ void buf_copy_options(buf_T *buf, int flags)
       buf->b_tc_flags = 0;
       buf->b_p_def = empty_option;
       buf->b_p_inc = empty_option;
-      buf->b_p_inex = vim_strsave(p_inex);
+      buf->b_p_inex = (char *)vim_strsave(p_inex);
       COPY_OPT_SCTX(buf, BV_INEX);
       buf->b_p_dict = empty_option;
       buf->b_p_tsr = empty_option;
       buf->b_p_tsrfu = empty_option;
-      buf->b_p_qe = vim_strsave(p_qe);
+      buf->b_p_qe = (char *)vim_strsave(p_qe);
       COPY_OPT_SCTX(buf, BV_QE);
       buf->b_p_udf = p_udf;
       COPY_OPT_SCTX(buf, BV_UDF);
@@ -4645,21 +4643,21 @@ void buf_copy_options(buf_T *buf, int flags)
        * or to a help buffer.
        */
       if (dont_do_help) {
-        buf->b_p_isk = save_p_isk;
-        if (p_vts && p_vts != empty_option && !buf->b_p_vts_array) {
+        buf->b_p_isk = (char *)save_p_isk;
+        if (p_vts && p_vts != (char_u *)empty_option && !buf->b_p_vts_array) {
           (void)tabstop_set(p_vts, &buf->b_p_vts_array);
         } else {
           buf->b_p_vts_array = NULL;
         }
       } else {
-        buf->b_p_isk = vim_strsave(p_isk);
+        buf->b_p_isk = (char *)vim_strsave(p_isk);
         COPY_OPT_SCTX(buf, BV_ISK);
         did_isk = true;
         buf->b_p_ts = p_ts;
         COPY_OPT_SCTX(buf, BV_TS);
-        buf->b_p_vts = vim_strsave(p_vts);
+        buf->b_p_vts = (char *)vim_strsave(p_vts);
         COPY_OPT_SCTX(buf, BV_VTS);
-        if (p_vts && p_vts != empty_option && !buf->b_p_vts_array) {
+        if (p_vts && p_vts != (char_u *)empty_option && !buf->b_p_vts_array) {
           (void)tabstop_set(p_vts, &buf->b_p_vts_array);
         } else {
           buf->b_p_vts_array = NULL;
@@ -5065,7 +5063,7 @@ bool has_format_option(int x)
   if (p_paste) {
     return false;
   }
-  return vim_strchr((char *)curbuf->b_p_fo, x) != NULL;
+  return vim_strchr(curbuf->b_p_fo, x) != NULL;
 }
 
 /// @returns true if "x" is present in 'shortmess' option, or
@@ -5105,7 +5103,7 @@ static void paste_option_changed(void)
           xfree(buf->b_p_vsts_nopaste);
         }
         buf->b_p_vsts_nopaste = buf->b_p_vsts && buf->b_p_vsts != empty_option
-                                    ? vim_strsave(buf->b_p_vsts)
+                                    ? xstrdup(buf->b_p_vsts)
                                     : NULL;
       }
 
@@ -5124,7 +5122,7 @@ static void paste_option_changed(void)
       if (p_vsts_nopaste) {
         xfree(p_vsts_nopaste);
       }
-      p_vsts_nopaste = p_vsts && p_vsts != empty_option
+      p_vsts_nopaste = p_vsts && p_vsts != (char_u *)empty_option
                           ? vim_strsave(p_vsts)
                           : NULL;
     }
@@ -5160,9 +5158,9 @@ static void paste_option_changed(void)
     p_sts = 0;
     p_ai = 0;
     if (p_vsts) {
-      free_string_option(p_vsts);
+      free_string_option((char *)p_vsts);
     }
-    p_vsts = empty_option;
+    p_vsts = (char_u *)empty_option;
   } else if (old_p_paste) {
     // Paste switched from on to off: Restore saved values.
 
@@ -5176,12 +5174,10 @@ static void paste_option_changed(void)
       if (buf->b_p_vsts) {
         free_string_option(buf->b_p_vsts);
       }
-      buf->b_p_vsts = buf->b_p_vsts_nopaste
-                        ? vim_strsave(buf->b_p_vsts_nopaste)
-                        : empty_option;
+      buf->b_p_vsts = buf->b_p_vsts_nopaste ? xstrdup(buf->b_p_vsts_nopaste) : empty_option;
       xfree(buf->b_p_vsts_array);
       if (buf->b_p_vsts && buf->b_p_vsts != empty_option) {
-        (void)tabstop_set(buf->b_p_vsts, &buf->b_p_vsts_array);
+        (void)tabstop_set((char_u *)buf->b_p_vsts, &buf->b_p_vsts_array);
       } else {
         buf->b_p_vsts_array = NULL;
       }
@@ -5203,9 +5199,9 @@ static void paste_option_changed(void)
     p_tw = p_tw_nopaste;
     p_wm = p_wm_nopaste;
     if (p_vsts) {
-      free_string_option(p_vsts);
+      free_string_option((char *)p_vsts);
     }
-    p_vsts = p_vsts_nopaste ? vim_strsave(p_vsts_nopaste) : empty_option;
+    p_vsts = p_vsts_nopaste ? vim_strsave(p_vsts_nopaste) : (char_u *)empty_option;
   }
 
   old_p_paste = p_paste;
@@ -5286,7 +5282,7 @@ int fill_culopt_flags(char_u *val, win_T *wp)
   char_u culopt_flags_new = 0;
 
   if (val == NULL) {
-    p = wp->w_p_culopt;
+    p = (char_u *)wp->w_p_culopt;
   } else {
     p = val;
   }
@@ -5437,7 +5433,7 @@ bool can_bs(int what)
 /// the file must be considered changed when the value is different.
 void save_file_ff(buf_T *buf)
 {
-  buf->b_start_ffc = *buf->b_p_ff;
+  buf->b_start_ffc = (unsigned char)(*buf->b_p_ff);
   buf->b_start_eol = buf->b_p_eol;
   buf->b_start_bomb = buf->b_p_bomb;
 
@@ -5445,7 +5441,7 @@ void save_file_ff(buf_T *buf)
   if (buf->b_start_fenc == NULL
       || STRCMP(buf->b_start_fenc, buf->b_p_fenc) != 0) {
     xfree(buf->b_start_fenc);
-    buf->b_start_fenc = (char *)vim_strsave(buf->b_p_fenc);
+    buf->b_start_fenc = xstrdup(buf->b_p_fenc);
   }
 }
 
@@ -5493,7 +5489,7 @@ bool briopt_check(win_T *wp)
   bool bri_sbr = false;
   int bri_list = 0;
 
-  char *p = (char *)wp->w_p_briopt;
+  char *p = wp->w_p_briopt;
   while (*p != NUL) {
     if (STRNCMP(p, "shift:", 6) == 0
         && ((p[6] == '-' && ascii_isdigit(p[7])) || ascii_isdigit(p[6]))) {
@@ -5550,16 +5546,16 @@ char_u *get_showbreak_value(win_T *const win)
     return p_sbr;
   }
   if (STRCMP(win->w_p_sbr, "NONE") == 0) {
-    return empty_option;
+    return (char_u *)empty_option;
   }
-  return win->w_p_sbr;
+  return (char_u *)win->w_p_sbr;
 }
 
 /// Return the current end-of-line type: EOL_DOS, EOL_UNIX or EOL_MAC.
 int get_fileformat(const buf_T *buf)
   FUNC_ATTR_PURE FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_NONNULL_ALL
 {
-  int c = *buf->b_p_ff;
+  int c = (unsigned char)(*buf->b_p_ff);
 
   if (buf->b_p_bin || c == 'u') {
     return EOL_UNIX;
@@ -5586,7 +5582,7 @@ int get_fileformat_force(const buf_T *buf, const exarg_T *eap)
         ? (eap->force_bin == FORCE_BIN) : buf->b_p_bin) {
       return EOL_UNIX;
     }
-    c = *buf->b_p_ff;
+    c = (unsigned char)(*buf->b_p_ff);
   }
   if (c == 'u') {
     return EOL_UNIX;
diff --git a/src/nvim/optionstr.c b/src/nvim/optionstr.c
index 78ae7e41ab..e1538e0491 100644
--- a/src/nvim/optionstr.c
+++ b/src/nvim/optionstr.c
@@ -254,14 +254,14 @@ void check_buf_options(buf_T *buf)
 /// memory, vim_strsave() returned NULL, which was replaced by empty_option by
 /// check_options().
 /// Does NOT check for P_ALLOCED flag!
-void free_string_option(char_u *p)
+void free_string_option(char *p)
 {
   if (p != empty_option) {
     xfree(p);
   }
 }
 
-void clear_string_option(char_u **pp)
+void clear_string_option(char **pp)
 {
   if (*pp != empty_option) {
     xfree(*pp);
@@ -269,7 +269,7 @@ void clear_string_option(char_u **pp)
   *pp = empty_option;
 }
 
-void check_string_option(char_u **pp)
+void check_string_option(char **pp)
 {
   if (*pp == NULL) {
     *pp = empty_option;
@@ -292,7 +292,7 @@ static void set_string_option_global(int opt_idx, char_u **varp)
   }
   if (!is_global_option(opt_idx) && p != varp) {
     s = vim_strsave(*varp);
-    free_string_option(*p);
+    free_string_option((char *)(*p));
     *p = s;
   }
 }
@@ -332,7 +332,7 @@ void set_string_option_direct(const char *name, int opt_idx, const char *val, in
   {
     varp = (char **)get_option_varp_scope(idx, both ? OPT_LOCAL : opt_flags);
     if ((opt_flags & OPT_FREE) && (get_option_flags(idx) & P_ALLOCED)) {
-      free_string_option((char_u *)(*varp));
+      free_string_option(*varp);
     }
     *varp = s;
 
@@ -346,8 +346,8 @@ void set_string_option_direct(const char *name, int opt_idx, const char *val, in
     // When setting both values of a global option with a local value,
     // make the local value empty, so that the global value is used.
     if (is_global_local_option(idx) && both) {
-      free_string_option((char_u *)(*varp));
-      *varp = (char *)empty_option;
+      free_string_option(*varp);
+      *varp = empty_option;
     }
     if (set_sid != SID_NONE) {
       sctx_T script_ctx;
@@ -662,7 +662,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     unsigned int *flags = &bkc_flags;
 
     if (opt_flags & OPT_LOCAL) {
-      bkc   = curbuf->b_p_bkc;
+      bkc = (char_u *)curbuf->b_p_bkc;
       flags = &curbuf->b_bkc_flags;
     }
 
@@ -687,12 +687,12 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
                *p_pm == '.' ? p_pm + 1 : p_pm) == 0) {
       errmsg = e_backupext_and_patchmode_are_equal;
     }
-  } else if (varp == &curwin->w_p_briopt) {  // 'breakindentopt'
+  } else if (varp == (char_u **)&curwin->w_p_briopt) {  // 'breakindentopt'
     if (briopt_check(curwin) == FAIL) {
       errmsg = e_invarg;
     }
   } else if (varp == &p_isi
-             || varp == &(curbuf->b_p_isk)
+             || varp == (char_u **)&(curbuf->b_p_isk)
              || varp == &p_isp
              || varp == &p_isf) {
     // 'isident', 'iskeyword', 'isprint or 'isfname' option: refill g_chartab[]
@@ -712,12 +712,12 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     }
   } else if (varp == &p_rtp || varp == &p_pp) {  // 'runtimepath' 'packpath'
     runtime_search_path_invalidate();
-  } else if (varp == &curwin->w_p_culopt
-             || gvarp == &curwin->w_allbuf_opt.wo_culopt) {  // 'cursorlineopt'
+  } else if (varp == (char_u **)&curwin->w_p_culopt
+             || gvarp == (char_u **)&curwin->w_allbuf_opt.wo_culopt) {  // 'cursorlineopt'
     if (**varp == NUL || fill_culopt_flags(*varp, curwin) != OK) {
       errmsg = e_invarg;
     }
-  } else if (varp == &curwin->w_p_cc) {  // 'colorcolumn'
+  } else if (varp == (char_u **)&curwin->w_p_cc) {  // 'colorcolumn'
     errmsg = check_colorcolumn(curwin);
   } else if (varp == &p_hlg) {  // 'helplang'
     // Check for "", "ab", "ab,cd", etc.
@@ -780,9 +780,9 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
         // value, that's not what we want here.  Disable the color
         // scheme and set the colors again.
         do_unlet(S_LEN("g:colors_name"), true);
-        free_string_option(p_bg);
+        free_string_option((char *)p_bg);
         p_bg = vim_strsave((char_u *)(dark ? "dark" : "light"));
-        check_string_option(&p_bg);
+        check_string_option((char **)&p_bg);
         init_highlight(false, false);
       }
     } else {
@@ -841,7 +841,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     p = (char *)enc_canonize(p_penc);
     xfree(p_penc);
     p_penc = (char_u *)p;
-  } else if (varp == &curbuf->b_p_keymap) {
+  } else if (varp == (char_u **)&curbuf->b_p_keymap) {
     if (!valid_filetype(*varp)) {
       errmsg = e_invarg;
     } else {
@@ -960,11 +960,11 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
       FOR_ALL_TAB_WINDOWS(tp, wp) {
         // If no error was returned above, we don't expect an error
         // here, so ignore the return value.
-        (void)set_chars_option(wp, &wp->w_p_lcs, true);
+        (void)set_chars_option(wp, (char_u **)&wp->w_p_lcs, true);
       }
       redraw_all_later(UPD_NOT_VALID);
     }
-  } else if (varp == &curwin->w_p_lcs) {  // local 'listchars'
+  } else if (varp == (char_u **)&curwin->w_p_lcs) {  // local 'listchars'
     errmsg = set_chars_option(curwin, varp, true);
   } else if (varp == &p_fcs) {  // global 'fillchars'
     errmsg = set_chars_option(curwin, varp, false);
@@ -977,11 +977,11 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
       FOR_ALL_TAB_WINDOWS(tp, wp) {
         // If no error was returned above, we don't expect an error
         // here, so ignore the return value.
-        (void)set_chars_option(wp, &wp->w_p_fcs, true);
+        (void)set_chars_option(wp, (char_u **)&wp->w_p_fcs, true);
       }
       redraw_all_later(UPD_NOT_VALID);
     }
-  } else if (varp == &curwin->w_p_fcs) {  // local 'fillchars'
+  } else if (varp == (char_u **)&curwin->w_p_fcs) {  // local 'fillchars'
     errmsg = set_chars_option(curwin, varp, true);
   } else if (varp == &p_cedit) {  // 'cedit'
     errmsg = check_cedit();
@@ -1117,11 +1117,11 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     if (opt_strings_flags(p_cb, p_cb_values, &cb_flags, true) != OK) {
       errmsg = e_invarg;
     }
-  } else if (varp == &(curwin->w_s->b_p_spl)  // 'spell'
-             || varp == &(curwin->w_s->b_p_spf)) {
+  } else if (varp == (char_u **)&(curwin->w_s->b_p_spl)  // 'spell'
+             || varp == (char_u **)&(curwin->w_s->b_p_spf)) {
     // When 'spelllang' or 'spellfile' is set and there is a window for this
     // buffer in which 'spell' is set load the wordlists.
-    const bool is_spellfile = varp == &(curwin->w_s->b_p_spf);
+    const bool is_spellfile = varp == (char_u **)&(curwin->w_s->b_p_spf);
 
     if ((is_spellfile && !valid_spellfile(*varp))
         || (!is_spellfile && !valid_spelllang(*varp))) {
@@ -1129,10 +1129,10 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     } else {
       errmsg = did_set_spell_option(is_spellfile);
     }
-  } else if (varp == &(curwin->w_s->b_p_spc)) {
+  } else if (varp == (char_u **)&(curwin->w_s->b_p_spc)) {
     // When 'spellcapcheck' is set compile the regexp program.
     errmsg = compile_cap_prog(curwin->w_s);
-  } else if (varp == &(curwin->w_s->b_p_spo)) {  // 'spelloptions'
+  } else if (varp == (char_u **)&(curwin->w_s->b_p_spo)) {  // 'spelloptions'
     if (**varp != NUL && STRCMP("camel", *varp) != 0) {
       errmsg = e_invarg;
     }
@@ -1146,14 +1146,14 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     }
   } else if (gvarp == &p_bh) {
     // When 'bufhidden' is set, check for valid value.
-    if (check_opt_strings(curbuf->b_p_bh, p_bufhidden_values, false) != OK) {
+    if (check_opt_strings((char_u *)curbuf->b_p_bh, p_bufhidden_values, false) != OK) {
       errmsg = e_invarg;
     }
   } else if (gvarp == &p_bt) {
     // When 'buftype' is set, check for valid value.
     if ((curbuf->terminal && curbuf->b_p_bt[0] != 't')
         || (!curbuf->terminal && curbuf->b_p_bt[0] == 't')
-        || check_opt_strings(curbuf->b_p_bt, p_buftype_values, false) != OK) {
+        || check_opt_strings((char_u *)curbuf->b_p_bt, p_buftype_values, false) != OK) {
       errmsg = e_invarg;
     } else {
       if (curwin->w_status_height || global_stl_height()) {
@@ -1241,7 +1241,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
       errmsg = e_invarg;
     }
 #endif
-  } else if (varp == &curwin->w_p_scl) {  // 'signcolumn'
+  } else if (varp == (char_u **)&curwin->w_p_scl) {  // 'signcolumn'
     if (check_signcolumn(*varp) != OK) {
       errmsg = e_invarg;
     }
@@ -1252,7 +1252,8 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
         && (curwin->w_p_nu || curwin->w_p_rnu)) {
       curwin->w_nrwidth_line_count = 0;
     }
-  } else if (varp == &curwin->w_p_fdc || varp == &curwin->w_allbuf_opt.wo_fdc) {
+  } else if (varp == (char_u **)&curwin->w_p_fdc
+             || varp == (char_u **)&curwin->w_allbuf_opt.wo_fdc) {
     // 'foldcolumn'
     if (**varp == NUL || check_opt_strings(*varp, p_fdc_values, false) != OK) {
       errmsg = e_invarg;
@@ -1266,7 +1267,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
                               &p, REPTERM_FROM_PART | REPTERM_DO_LT, NULL,
                               CPO_TO_CPO_FLAGS);
       if (p != NULL) {
-        free_string_option(p_pt);
+        free_string_option((char *)p_pt);
         p_pt = (char_u *)p;
       }
     }
@@ -1286,7 +1287,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     unsigned int *flags;
 
     if (opt_flags & OPT_LOCAL) {
-      p = (char *)curbuf->b_p_tc;
+      p = curbuf->b_p_tc;
       flags = &curbuf->b_tc_flags;
     } else {
       p = (char *)p_tc;
@@ -1308,7 +1309,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     if (diffopt_changed() == FAIL) {
       errmsg = e_invarg;
     }
-  } else if (gvarp == &curwin->w_allbuf_opt.wo_fdm) {  // 'foldmethod'
+  } else if (gvarp == (char_u **)&curwin->w_allbuf_opt.wo_fdm) {  // 'foldmethod'
     if (check_opt_strings(*varp, p_fdm_values, false) != OK
         || *curwin->w_p_fdm == NUL) {
       errmsg = e_invarg;
@@ -1318,11 +1319,11 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
         newFoldLevel();
       }
     }
-  } else if (varp == &curwin->w_p_fde) {  // 'foldexpr'
+  } else if (varp == (char_u **)&curwin->w_p_fde) {  // 'foldexpr'
     if (foldmethodIsExpr(curwin)) {
       foldUpdateAll(curwin);
     }
-  } else if (gvarp == &curwin->w_allbuf_opt.wo_fmr) {  // 'foldmarker'
+  } else if (gvarp == (char_u **)&curwin->w_allbuf_opt.wo_fmr) {  // 'foldmarker'
     p = vim_strchr((char *)(*varp), ',');
     if (p == NULL) {
       errmsg = N_("E536: comma required");
@@ -1343,7 +1344,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     if (check_opt_strings(p_fcl, p_fcl_values, true) != OK) {
       errmsg = e_invarg;
     }
-  } else if (gvarp == &curwin->w_allbuf_opt.wo_fdi) {  // 'foldignore'
+  } else if (gvarp == (char_u **)&curwin->w_allbuf_opt.wo_fdi) {  // 'foldignore'
     if (foldmethodIsIndent(curwin)) {
       foldUpdateAll(curwin);
     }
@@ -1352,7 +1353,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     unsigned int *flags = &ve_flags;
 
     if (opt_flags & OPT_LOCAL) {
-      ve = curwin->w_p_ve;
+      ve = (char_u *)curwin->w_p_ve;
       flags = &curwin->w_ve_flags;
     }
 
@@ -1413,7 +1414,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
       // even when the value comes from a modeline.
       *value_checked = true;
     }
-  } else if (varp == &curwin->w_p_winhl) {
+  } else if (varp == (char_u **)&curwin->w_p_winhl) {
     if (!parse_winhl_opt(curwin)) {
       errmsg = e_invarg;
     }
@@ -1421,7 +1422,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     if (opt_strings_flags(p_tpf, p_tpf_values, &tpf_flags, true) != OK) {
       errmsg = e_invarg;
     }
-  } else if (varp == &(curbuf->b_p_vsts)) {  // 'varsofttabstop'
+  } else if (varp == (char_u **)&(curbuf->b_p_vsts)) {  // 'varsofttabstop'
     char_u *cp;
 
     if (!(*varp)[0] || ((*varp)[0] == '0' && !(*varp)[1])) {
@@ -1446,7 +1447,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
         }
       }
     }
-  } else if (varp == &(curbuf->b_p_vts)) {  // 'vartabstop'
+  } else if (varp == (char_u **)&(curbuf->b_p_vts)) {  // 'vartabstop'
     char_u *cp;
 
     if (!(*varp)[0] || ((*varp)[0] == '0' && !(*varp)[1])) {
@@ -1492,9 +1493,9 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
       p = (char *)SHM_ALL;
     } else if (varp == (char_u **)&(p_cpo)) {  // 'cpoptions'
       p = CPO_VI;
-    } else if (varp == &(curbuf->b_p_fo)) {  // 'formatoptions'
+    } else if (varp == (char_u **)&(curbuf->b_p_fo)) {  // 'formatoptions'
       p = FO_ALL;
-    } else if (varp == &curwin->w_p_cocu) {  // 'concealcursor'
+    } else if (varp == (char_u **)&curwin->w_p_cocu) {  // 'concealcursor'
       p = COCU_ALL;
     } else if (varp == &p_mouse) {  // 'mouse'
       p = MOUSE_ALL;
@@ -1511,7 +1512,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
 
   // If error detected, restore the previous value.
   if (errmsg != NULL) {
-    free_string_option(*varp);
+    free_string_option((char *)(*varp));
     *varp = oldval;
     // When resetting some values, need to act on it.
     if (did_chartab) {
@@ -1524,7 +1525,7 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
     // Use "free_oldval", because recursiveness may change the flags under
     // our fingers (esp. init_highlight()).
     if (free_oldval) {
-      free_string_option(oldval);
+      free_string_option((char *)oldval);
     }
     set_option_flag(opt_idx, P_ALLOCED);
 
@@ -1533,8 +1534,8 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
       // global option with local value set to use global value; free
       // the local value and make it empty
       p = (char *)get_option_varp_scope(opt_idx, OPT_LOCAL);
-      free_string_option(*(char_u **)p);
-      *(char_u **)p = empty_option;
+      free_string_option(*(char **)p);
+      *(char **)p = empty_option;
     } else if (!(opt_flags & OPT_LOCAL) && opt_flags != OPT_GLOBAL) {
       // May set global value for local option.
       set_string_option_global(opt_idx, varp);
@@ -1542,17 +1543,17 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
 
     // Trigger the autocommand only after setting the flags.
     // When 'syntax' is set, load the syntax of that name
-    if (varp == &(curbuf->b_p_syn)) {
+    if (varp == (char_u **)&(curbuf->b_p_syn)) {
       static int syn_recursive = 0;
 
       syn_recursive++;
       // Only pass true for "force" when the value changed or not used
       // recursively, to avoid endless recurrence.
-      apply_autocmds(EVENT_SYNTAX, (char *)curbuf->b_p_syn, curbuf->b_fname,
+      apply_autocmds(EVENT_SYNTAX, curbuf->b_p_syn, curbuf->b_fname,
                      value_changed || syn_recursive == 1, curbuf);
       curbuf->b_flags |= BF_SYN_SET;
       syn_recursive--;
-    } else if (varp == &(curbuf->b_p_ft)) {
+    } else if (varp == (char_u **)&(curbuf->b_p_ft)) {
       // 'filetype' is set, trigger the FileType autocommand
       // Skip this when called from a modeline and the filetype was
       // already set to this value.
@@ -1568,19 +1569,19 @@ char *did_set_string_option(int opt_idx, char_u **varp, char_u *oldval, char *er
         did_filetype = true;
         // Only pass true for "force" when the value changed or not
         // used recursively, to avoid endless recurrence.
-        apply_autocmds(EVENT_FILETYPE, (char *)curbuf->b_p_ft, curbuf->b_fname,
+        apply_autocmds(EVENT_FILETYPE, curbuf->b_p_ft, curbuf->b_fname,
                        value_changed || ft_recursive == 1, curbuf);
         ft_recursive--;
         // Just in case the old "curbuf" is now invalid
-        if (varp != &(curbuf->b_p_ft)) {
+        if (varp != (char_u **)&(curbuf->b_p_ft)) {
           varp = NULL;
         }
         secure = secure_save;
       }
     }
-    if (varp == &(curwin->w_s->b_p_spl)) {
+    if (varp == (char_u **)&(curwin->w_s->b_p_spl)) {
       char_u fname[200];
-      char_u *q = curwin->w_s->b_p_spl;
+      char_u *q = (char_u *)curwin->w_s->b_p_spl;
 
       // Skip the first name if it is "cjk".
       if (STRNCMP(q, "cjk,", 4) == 0) {
diff --git a/src/nvim/os/shell.c b/src/nvim/os/shell.c
index b793b8f9c6..574543b1a5 100644
--- a/src/nvim/os/shell.c
+++ b/src/nvim/os/shell.c
@@ -74,7 +74,7 @@ static bool have_wildcard(int num, char **file)
 static bool have_dollars(int num, char **file)
 {
   for (int i = 0; i < num; i++) {
-    if (vim_strchr((char *)file[i], '$') != NULL) {
+    if (vim_strchr(file[i], '$') != NULL) {
       return true;
     }
   }
diff --git a/src/nvim/path.c b/src/nvim/path.c
index 3b3156bc73..e4215c89c2 100644
--- a/src/nvim/path.c
+++ b/src/nvim/path.c
@@ -376,16 +376,16 @@ int path_fnamencmp(const char *const fname1, const char *const fname2, size_t le
   const char *p1 = fname1;
   const char *p2 = fname2;
   while (len > 0) {
-    c1 = utf_ptr2char((const char_u *)p1);
-    c2 = utf_ptr2char((const char_u *)p2);
+    c1 = utf_ptr2char(p1);
+    c2 = utf_ptr2char(p2);
     if ((c1 == NUL || c2 == NUL
          || (!((c1 == '/' || c1 == '\\') && (c2 == '\\' || c2 == '/'))))
         && (p_fic ? (c1 != c2 && CH_FOLD(c1) != CH_FOLD(c2)) : c1 != c2)) {
       break;
     }
-    len -= (size_t)utfc_ptr2len((const char_u *)p1);
-    p1 += utfc_ptr2len((const char_u *)p1);
-    p2 += utfc_ptr2len((const char_u *)p2);
+    len -= (size_t)utfc_ptr2len(p1);
+    p1 += utfc_ptr2len(p1);
+    p2 += utfc_ptr2len(p2);
   }
   return p_fic ? CH_FOLD(c1) - CH_FOLD(c2) : c1 - c2;
 #else
@@ -843,7 +843,7 @@ static bool is_unique(char_u *maybe_unique, garray_T *gap, int i)
  */
 static void expand_path_option(char_u *curdir, garray_T *gap)
 {
-  char_u *path_option = *curbuf->b_p_path == NUL ? p_path : curbuf->b_p_path;
+  char_u *path_option = *curbuf->b_p_path == NUL ? p_path : (char_u *)curbuf->b_p_path;
   char_u *buf = xmalloc(MAXPATHL);
 
   while (*path_option != NUL) {
@@ -1684,7 +1684,7 @@ void simplify_filename(char_u *filename)
 static char *eval_includeexpr(const char *const ptr, const size_t len)
 {
   set_vim_var_string(VV_FNAME, ptr, (ptrdiff_t)len);
-  char *res = eval_to_string_safe((char *)curbuf->b_p_inex, NULL,
+  char *res = eval_to_string_safe(curbuf->b_p_inex, NULL,
                                   was_set_insecurely(curwin, "includeexpr", OPT_LOCAL));
   set_vim_var_string(VV_FNAME, NULL, 0);
   return res;
diff --git a/src/nvim/quickfix.c b/src/nvim/quickfix.c
index 6ce2b4d878..a6d5098a20 100644
--- a/src/nvim/quickfix.c
+++ b/src/nvim/quickfix.c
@@ -1091,7 +1091,7 @@ static int qf_init_ext(qf_info_T *qi, int qf_idx, const char *restrict efile, bu
 
   // Use the local value of 'errorformat' if it's set.
   if (errorformat == p_efm && tv == NULL && buf && *buf->b_p_efm != NUL) {
-    efm = (char *)buf->b_p_efm;
+    efm = buf->b_p_efm;
   } else {
     efm = errorformat;
   }
@@ -2534,7 +2534,7 @@ static int qf_open_new_file_win(qf_info_T *ll_ref)
   if (win_split(0, flags) == FAIL) {
     return FAIL;  // not enough room for window
   }
-  p_swb = empty_option;  // don't split again
+  p_swb = (char_u *)empty_option;  // don't split again
   swb_flags = 0;
   RESET_BINDING(curwin);
   if (ll_ref != NULL) {
@@ -2994,7 +2994,7 @@ theend:
     qfl->qf_ptr = qf_ptr;
     qfl->qf_index = qf_index;
   }
-  if (p_swb != (char_u *)old_swb && p_swb == empty_option) {
+  if (p_swb != (char_u *)old_swb && p_swb == (char_u *)empty_option) {
     // Restore old 'switchbuf' value, but not when an autocommand or
     // modeline has changed the value.
     p_swb = (char_u *)old_swb;
@@ -4183,7 +4183,7 @@ int grep_internal(cmdidx_T cmdidx)
           || cmdidx == CMD_grepadd
           || cmdidx == CMD_lgrepadd)
          && STRCMP("internal",
-                   *curbuf->b_p_gp == NUL ? p_gp : curbuf->b_p_gp) == 0;
+                   *curbuf->b_p_gp == NUL ? p_gp : (char_u *)curbuf->b_p_gp) == 0;
 }
 
 // Return the make/grep autocmd name.
@@ -4241,7 +4241,7 @@ static char *make_get_fullcmd(const char *makecmd, const char *fname)
 // Used for ":make", ":lmake", ":grep", ":lgrep", ":grepadd", and ":lgrepadd"
 void ex_make(exarg_T *eap)
 {
-  char *enc = (*curbuf->b_p_menc != NUL) ? (char *)curbuf->b_p_menc : (char *)p_menc;
+  char *enc = (*curbuf->b_p_menc != NUL) ? curbuf->b_p_menc : (char *)p_menc;
 
   // Redirect ":grep" to ":vimgrep" if 'grepprg' is "internal".
   if (grep_internal(eap->cmdidx)) {
@@ -4981,7 +4981,7 @@ void ex_cfile(exarg_T *eap)
     set_string_option_direct("ef", -1, eap->arg, OPT_FREE, 0);
   }
 
-  char *enc = (*curbuf->b_p_menc != NUL) ? (char *)curbuf->b_p_menc : (char *)p_menc;
+  char *enc = (*curbuf->b_p_menc != NUL) ? curbuf->b_p_menc : (char *)p_menc;
 
   if (is_loclist_cmd(eap->cmdidx)) {
     wp = curwin;
@@ -5305,7 +5305,7 @@ static int vgr_process_args(exarg_T *eap, vgr_args_T *args)
   }
 
   // Parse the list of arguments, wildcards have already been expanded.
-  if (get_arglist_exp((char_u *)p, &args->fcount, &args->fnames, true) == FAIL) {
+  if (get_arglist_exp(p, &args->fcount, &args->fnames, true) == FAIL) {
     return FAIL;
   }
   if (args->fcount == 0) {
@@ -5429,7 +5429,7 @@ static int vgr_process_files(win_T *wp, qf_info_T *qi, vgr_args_T *cmd_args, boo
           // options!
           aco_save_T aco;
           aucmd_prepbuf(&aco, buf);
-          apply_autocmds(EVENT_FILETYPE, (char *)buf->b_p_ft, buf->b_fname, true, buf);
+          apply_autocmds(EVENT_FILETYPE, buf->b_p_ft, buf->b_fname, true, buf);
           do_modelines(OPT_NOWIN);
           aucmd_restbuf(&aco);
         }
@@ -7065,7 +7065,7 @@ void ex_helpgrep(exarg_T *eap)
   bool updated = false;
   // Make 'cpoptions' empty, the 'l' flag should not be used here.
   char *const save_cpo = p_cpo;
-  p_cpo = (char *)empty_option;
+  p_cpo = empty_option;
 
   bool new_qi = false;
   if (is_loclist_cmd(eap->cmdidx)) {
@@ -7096,7 +7096,7 @@ void ex_helpgrep(exarg_T *eap)
     updated = true;
   }
 
-  if ((char_u *)p_cpo == empty_option) {
+  if (p_cpo == empty_option) {
     p_cpo = save_cpo;
   } else {
     // Darn, some plugin changed the value.  If it's still empty it was
@@ -7104,7 +7104,7 @@ void ex_helpgrep(exarg_T *eap)
     if (*p_cpo == NUL) {
       set_option_value_give_err("cpo", 0L, save_cpo, 0);
     }
-    free_string_option((char_u *)save_cpo);
+    free_string_option(save_cpo);
   }
 
   if (updated) {
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index 58e195b745..2ed31ae8a9 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -69,7 +69,7 @@ bool conceal_cursor_line(const win_T *wp)
   } else {
     return false;
   }
-  return vim_strchr((char *)wp->w_p_cocu, c) != NULL;
+  return vim_strchr(wp->w_p_cocu, c) != NULL;
 }
 
 /// Whether cursorline is drawn in a special way
@@ -535,7 +535,7 @@ bool get_keymap_str(win_T *wp, char *fmt, char *buf, int len)
     curwin = old_curwin;
     if (p == NULL || *p == NUL) {
       if (wp->w_buffer->b_kmap_state & KEYMAP_LOADED) {
-        p = (char *)wp->w_buffer->b_p_keymap;
+        p = wp->w_buffer->b_p_keymap;
       } else {
         p = "lang";
       }
@@ -1347,16 +1347,16 @@ char *set_chars_option(win_T *wp, char_u **varp, bool set)
     { &wp->w_p_lcs_chars.conceal, "conceal",  NUL },
   };
 
-  if (varp == &p_lcs || varp == &wp->w_p_lcs) {
+  if (varp == &p_lcs || varp == (char_u **)&wp->w_p_lcs) {
     tab = lcs_tab;
     entries = ARRAY_SIZE(lcs_tab);
-    if (varp == &wp->w_p_lcs && wp->w_p_lcs[0] == NUL) {
+    if (varp == (char_u **)&wp->w_p_lcs && wp->w_p_lcs[0] == NUL) {
       varp = &p_lcs;
     }
   } else {
     tab = fcs_tab;
     entries = ARRAY_SIZE(fcs_tab);
-    if (varp == &wp->w_p_fcs && wp->w_p_fcs[0] == NUL) {
+    if (varp == (char_u **)&wp->w_p_fcs && wp->w_p_fcs[0] == NUL) {
       varp = &p_fcs;
     }
   }
@@ -1370,7 +1370,7 @@ char *set_chars_option(win_T *wp, char_u **varp, bool set)
           *(tab[i].cp) = tab[i].def;
         }
       }
-      if (varp == &p_lcs || varp == &wp->w_p_lcs) {
+      if (varp == &p_lcs || varp == (char_u **)&wp->w_p_lcs) {
         wp->w_p_lcs_chars.tab1 = NUL;
         wp->w_p_lcs_chars.tab3 = NUL;
 
@@ -1439,7 +1439,7 @@ char *set_chars_option(win_T *wp, char_u **varp, bool set)
       if (i == entries) {
         len = (int)STRLEN("multispace");
         len2 = (int)STRLEN("leadmultispace");
-        if ((varp == &p_lcs || varp == &wp->w_p_lcs)
+        if ((varp == &p_lcs || varp == (char_u **)&wp->w_p_lcs)
             && STRNCMP(p, "multispace", len) == 0
             && p[len] == ':'
             && p[len + 1] != NUL) {
@@ -1470,7 +1470,7 @@ char *set_chars_option(win_T *wp, char_u **varp, bool set)
             }
             p = s;
           }
-        } else if ((varp == &p_lcs || varp == &wp->w_p_lcs)
+        } else if ((varp == &p_lcs || varp == (char_u **)&wp->w_p_lcs)
                    && STRNCMP(p, "leadmultispace", len2) == 0
                    && p[len2] == ':'
                    && p[len2 + 1] != NUL) {
@@ -1527,10 +1527,10 @@ char *check_chars_options(void)
     return e_conflicts_with_value_of_fillchars;
   }
   FOR_ALL_TAB_WINDOWS(tp, wp) {
-    if (set_chars_option(wp, &wp->w_p_lcs, true) != NULL) {
+    if (set_chars_option(wp, (char_u **)&wp->w_p_lcs, true) != NULL) {
       return e_conflicts_with_value_of_listchars;
     }
-    if (set_chars_option(wp, &wp->w_p_fcs, true) != NULL) {
+    if (set_chars_option(wp, (char_u **)&wp->w_p_fcs, true) != NULL) {
       return e_conflicts_with_value_of_fillchars;
     }
   }
diff --git a/src/nvim/search.c b/src/nvim/search.c
index 6e5e12dd17..34ff30a8da 100644
--- a/src/nvim/search.c
+++ b/src/nvim/search.c
@@ -1696,34 +1696,34 @@ static bool find_rawstring_end(char_u *linep, pos_T *startpos, pos_T *endpos)
 static void find_mps_values(int *initc, int *findc, bool *backwards, bool switchit)
   FUNC_ATTR_NONNULL_ALL
 {
-  char_u *ptr = curbuf->b_p_mps;
+  char *ptr = curbuf->b_p_mps;
 
   while (*ptr != NUL) {
-    if (utf_ptr2char((char *)ptr) == *initc) {
+    if (utf_ptr2char(ptr) == *initc) {
       if (switchit) {
         *findc = *initc;
-        *initc = utf_ptr2char((char *)ptr + utfc_ptr2len((char *)ptr) + 1);
+        *initc = utf_ptr2char(ptr + utfc_ptr2len(ptr) + 1);
         *backwards = true;
       } else {
-        *findc = utf_ptr2char((char *)ptr + utfc_ptr2len((char *)ptr) + 1);
+        *findc = utf_ptr2char(ptr + utfc_ptr2len(ptr) + 1);
         *backwards = false;
       }
       return;
     }
-    char_u *prev = ptr;
-    ptr += utfc_ptr2len((char *)ptr) + 1;
-    if (utf_ptr2char((char *)ptr) == *initc) {
+    char *prev = ptr;
+    ptr += utfc_ptr2len(ptr) + 1;
+    if (utf_ptr2char(ptr) == *initc) {
       if (switchit) {
         *findc = *initc;
-        *initc = utf_ptr2char((char *)prev);
+        *initc = utf_ptr2char(prev);
         *backwards = false;
       } else {
-        *findc = utf_ptr2char((char *)prev);
+        *findc = utf_ptr2char(prev);
         *backwards = true;
       }
       return;
     }
-    ptr += utfc_ptr2len((char *)ptr);
+    ptr += utfc_ptr2len(ptr);
     if (*ptr == ',') {
       ptr++;
     }
@@ -2376,7 +2376,7 @@ void showmatch(int c)
    * Only show match for chars in the 'matchpairs' option.
    */
   // 'matchpairs' is "x:y,x:y"
-  for (p = curbuf->b_p_mps; *p != NUL; p++) {
+  for (p = (char_u *)curbuf->b_p_mps; *p != NUL; p++) {
     if (utf_ptr2char((char *)p) == c && (curwin->w_p_rl ^ p_ri)) {
       break;
     }
@@ -4090,8 +4090,7 @@ bool current_quote(oparg_T *oap, long count, bool include, int quotechar)
       if (col_start < 0) {
         goto abort_search;
       }
-      col_end = find_next_quote(line, col_start + 1, quotechar,
-                                curbuf->b_p_qe);
+      col_end = find_next_quote(line, col_start + 1, quotechar, (char_u *)curbuf->b_p_qe);
       if (col_end < 0) {
         // We were on a starting quote perhaps?
         col_end = col_start;
@@ -4102,8 +4101,7 @@ bool current_quote(oparg_T *oap, long count, bool include, int quotechar)
       if (line[col_end] != quotechar) {
         goto abort_search;
       }
-      col_start = find_prev_quote(line, col_end, quotechar,
-                                  curbuf->b_p_qe);
+      col_start = find_prev_quote(line, col_end, quotechar, (char_u *)curbuf->b_p_qe);
       if (line[col_start] != quotechar) {
         // We were on an ending quote perhaps?
         col_start = col_end;
@@ -4132,8 +4130,7 @@ bool current_quote(oparg_T *oap, long count, bool include, int quotechar)
         goto abort_search;
       }
       // Find close quote character.
-      col_end = find_next_quote(line, col_start + 1, quotechar,
-                                curbuf->b_p_qe);
+      col_end = find_next_quote(line, col_start + 1, quotechar, (char_u *)curbuf->b_p_qe);
       if (col_end < 0) {
         goto abort_search;
       }
@@ -4146,7 +4143,7 @@ bool current_quote(oparg_T *oap, long count, bool include, int quotechar)
     }
   } else {
     // Search backward for a starting quote.
-    col_start = find_prev_quote(line, col_start, quotechar, curbuf->b_p_qe);
+    col_start = find_prev_quote(line, col_start, quotechar, (char_u *)curbuf->b_p_qe);
     if (line[col_start] != quotechar) {
       // No quote before the cursor, look after the cursor.
       col_start = find_next_quote(line, col_start, quotechar, NULL);
@@ -4156,8 +4153,7 @@ bool current_quote(oparg_T *oap, long count, bool include, int quotechar)
     }
 
     // Find close quote character.
-    col_end = find_next_quote(line, col_start + 1, quotechar,
-                              curbuf->b_p_qe);
+    col_end = find_next_quote(line, col_start + 1, quotechar, (char_u *)curbuf->b_p_qe);
     if (col_end < 0) {
       goto abort_search;
     }
@@ -5375,7 +5371,7 @@ void find_pattern_in_path(char_u *ptr, Direction dir, size_t len, bool whole, bo
       goto fpip_end;
     }
   }
-  inc_opt = (*curbuf->b_p_inc == NUL) ? p_inc : curbuf->b_p_inc;
+  inc_opt = (*curbuf->b_p_inc == NUL) ? p_inc : (char_u *)curbuf->b_p_inc;
   if (*inc_opt != NUL) {
     incl_regmatch.regprog = vim_regcomp((char *)inc_opt, p_magic ? RE_MAGIC : 0);
     if (incl_regmatch.regprog == NULL) {
@@ -5385,7 +5381,7 @@ void find_pattern_in_path(char_u *ptr, Direction dir, size_t len, bool whole, bo
   }
   if (type == FIND_DEFINE && (*curbuf->b_p_def != NUL || *p_def != NUL)) {
     def_regmatch.regprog = vim_regcomp(*curbuf->b_p_def == NUL
-                                       ? (char *)p_def : (char *)curbuf->b_p_def,
+                                       ? (char *)p_def : curbuf->b_p_def,
                                        p_magic ? RE_MAGIC : 0);
     if (def_regmatch.regprog == NULL) {
       goto fpip_end;
diff --git a/src/nvim/spell.c b/src/nvim/spell.c
index ecb97afd02..439fcff8a0 100644
--- a/src/nvim/spell.c
+++ b/src/nvim/spell.c
@@ -1837,7 +1837,7 @@ char *did_set_spelllang(win_T *wp)
 
   // Make a copy of 'spelllang', the SpellFileMissing autocommands may change
   // it under our fingers.
-  spl_copy = vim_strsave(wp->w_s->b_p_spl);
+  spl_copy = vim_strsave((char_u *)wp->w_s->b_p_spl);
 
   wp->w_s->b_cjk = 0;
 
@@ -1966,7 +1966,7 @@ char *did_set_spelllang(win_T *wp)
   // round 1: load first name in 'spellfile'.
   // round 2: load second name in 'spellfile.
   // etc.
-  spf = (char *)curwin->w_s->b_p_spf;
+  spf = curwin->w_s->b_p_spf;
   for (round = 0; round == 0 || *spf != NUL; round++) {
     if (round == 0) {
       // Internal wordlist, if there is one.
@@ -2120,13 +2120,13 @@ static void use_midword(slang_T *lp, win_T *wp)
       wp->w_s->b_spell_ismw[c] = true;
     } else if (wp->w_s->b_spell_ismw_mb == NULL) {
       // First multi-byte char in "b_spell_ismw_mb".
-      wp->w_s->b_spell_ismw_mb = vim_strnsave(p, (size_t)l);
+      wp->w_s->b_spell_ismw_mb = (char *)vim_strnsave(p, (size_t)l);
     } else {
       // Append multi-byte chars to "b_spell_ismw_mb".
       const int n = (int)STRLEN(wp->w_s->b_spell_ismw_mb);
-      char_u *bp = vim_strnsave(wp->w_s->b_spell_ismw_mb, (size_t)n + (size_t)l);
+      char_u *bp = vim_strnsave((char_u *)wp->w_s->b_spell_ismw_mb, (size_t)n + (size_t)l);
       xfree(wp->w_s->b_spell_ismw_mb);
-      wp->w_s->b_spell_ismw_mb = bp;
+      wp->w_s->b_spell_ismw_mb = (char *)bp;
       STRLCPY(bp + n, p, l + 1);
     }
     p += l;
@@ -2359,7 +2359,7 @@ bool spell_iswordp(const char_u *p, const win_T *wp)
     if (c < 256
         ? wp->w_s->b_spell_ismw[c]
         : (wp->w_s->b_spell_ismw_mb != NULL
-           && vim_strchr((char *)wp->w_s->b_spell_ismw_mb, c) != NULL)) {
+           && vim_strchr(wp->w_s->b_spell_ismw_mb, c) != NULL)) {
       s = p + l;
     }
   }
@@ -2405,7 +2405,7 @@ static bool spell_iswordp_w(const int *p, const win_T *wp)
 
   if (*p <
       256 ? wp->w_s->b_spell_ismw[*p] : (wp->w_s->b_spell_ismw_mb != NULL
-                                         && vim_strchr((char *)wp->w_s->b_spell_ismw_mb,
+                                         && vim_strchr(wp->w_s->b_spell_ismw_mb,
                                                        *p) != NULL)) {
     s = p + 1;
   } else {
@@ -3599,7 +3599,7 @@ char *compile_cap_prog(synblock_T *synblock)
     synblock->b_cap_prog = NULL;
   } else {
     // Prepend a ^ so that we only match at one column
-    char_u *re = concat_str((char_u *)"^", synblock->b_p_spc);
+    char_u *re = concat_str((char_u *)"^", (char_u *)synblock->b_p_spc);
     synblock->b_cap_prog = vim_regcomp((char *)re, RE_MAGIC);
     xfree(re);
     if (synblock->b_cap_prog == NULL) {
diff --git a/src/nvim/spellfile.c b/src/nvim/spellfile.c
index 676eff9f4a..0fd7351d26 100644
--- a/src/nvim/spellfile.c
+++ b/src/nvim/spellfile.c
@@ -4877,12 +4877,12 @@ void ex_mkspell(exarg_T *eap)
 {
   int fcount;
   char **fnames;
-  char_u *arg = (char_u *)eap->arg;
+  char *arg = eap->arg;
   bool ascii = false;
 
   if (STRNCMP(arg, "-ascii", 6) == 0) {
     ascii = true;
-    arg = (char_u *)skipwhite((char *)arg + 6);
+    arg = skipwhite(arg + 6);
   }
 
   // Expand all the remaining arguments (e.g., $VIMRUNTIME).
@@ -5552,7 +5552,7 @@ void spell_add_word(char_u *word, int len, SpellAddType what, int idx, bool undo
     }
     fnamebuf = xmalloc(MAXPATHL);
 
-    for (spf = curwin->w_s->b_p_spf, i = 1; *spf != NUL; i++) {
+    for (spf = (char_u *)curwin->w_s->b_p_spf, i = 1; *spf != NUL; i++) {
       copy_option_part((char **)&spf, (char *)fnamebuf, MAXPATHL, ",");
       if (i == idx) {
         break;
@@ -5680,14 +5680,14 @@ static void init_spellfile(void)
   char_u *rtp;
   char_u *lend;
   bool aspath = false;
-  char_u *lstart = curbuf->b_s.b_p_spl;
+  char_u *lstart = (char_u *)curbuf->b_s.b_p_spl;
 
   if (*curwin->w_s->b_p_spl != NUL && !GA_EMPTY(&curwin->w_s->b_langp)) {
     buf = xmalloc(MAXPATHL);
 
     // Find the end of the language name.  Exclude the region.  If there
     // is a path separator remember the start of the tail.
-    for (lend = curwin->w_s->b_p_spl; *lend != NUL
+    for (lend = (char_u *)curwin->w_s->b_p_spl; *lend != NUL
          && vim_strchr(",._", *lend) == NULL; lend++) {
       if (vim_ispathsep(*lend)) {
         aspath = true;
@@ -5702,8 +5702,7 @@ static void init_spellfile(void)
       if (aspath) {
         // Use directory of an entry with path, e.g., for
         // "/dir/lg.utf-8.spl" use "/dir".
-        STRLCPY(buf, curbuf->b_s.b_p_spl,
-                lstart - curbuf->b_s.b_p_spl);
+        STRLCPY(buf, curbuf->b_s.b_p_spl, lstart - (char_u *)curbuf->b_s.b_p_spl);
       } else {
         // Copy the path from 'runtimepath' to buf[].
         copy_option_part((char **)&rtp, (char *)buf, MAXPATHL, ",");
@@ -5712,8 +5711,7 @@ static void init_spellfile(void)
         // Use the first language name from 'spelllang' and the
         // encoding used in the first loaded .spl file.
         if (aspath) {
-          STRLCPY(buf, curbuf->b_s.b_p_spl,
-                  lend - curbuf->b_s.b_p_spl + 1);
+          STRLCPY(buf, curbuf->b_s.b_p_spl, lend - (char_u *)curbuf->b_s.b_p_spl + 1);
         } else {
           // Create the "spell" directory if it doesn't exist yet.
           l = (int)STRLEN(buf);
diff --git a/src/nvim/statusline.c b/src/nvim/statusline.c
index e868a79b9a..d7277b38ae 100644
--- a/src/nvim/statusline.c
+++ b/src/nvim/statusline.c
@@ -522,7 +522,7 @@ void win_redr_custom(win_T *wp, bool draw_winbar, bool draw_ruler)
       use_sandbox = was_set_insecurely(wp, "rulerformat", 0);
     } else {
       if (*wp->w_p_stl != NUL) {
-        stl = wp->w_p_stl;
+        stl = (char_u *)wp->w_p_stl;
       } else {
         stl = p_stl;
       }
diff --git a/src/nvim/syntax.c b/src/nvim/syntax.c
index 7794499582..69a5225edc 100644
--- a/src/nvim/syntax.c
+++ b/src/nvim/syntax.c
@@ -3162,7 +3162,7 @@ static void syn_cmd_iskeyword(exarg_T *eap, int syncing)
     msg_puts("\n");
     if (curwin->w_s->b_syn_isk != empty_option) {
       msg_puts("syntax iskeyword ");
-      msg_outtrans((char *)curwin->w_s->b_syn_isk);
+      msg_outtrans(curwin->w_s->b_syn_isk);
     } else {
       msg_outtrans(_("syntax iskeyword not set"));
     }
@@ -3172,15 +3172,15 @@ static void syn_cmd_iskeyword(exarg_T *eap, int syncing)
       clear_string_option(&curwin->w_s->b_syn_isk);
     } else {
       memmove(save_chartab, curbuf->b_chartab, (size_t)32);
-      save_isk = curbuf->b_p_isk;
-      curbuf->b_p_isk = vim_strsave(arg);
+      save_isk = (char_u *)curbuf->b_p_isk;
+      curbuf->b_p_isk = (char *)vim_strsave(arg);
 
       buf_init_chartab(curbuf, false);
       memmove(curwin->w_s->b_syn_chartab, curbuf->b_chartab, (size_t)32);
       memmove(curbuf->b_chartab, save_chartab, (size_t)32);
       clear_string_option(&curwin->w_s->b_syn_isk);
       curwin->w_s->b_syn_isk = curbuf->b_p_isk;
-      curbuf->b_p_isk = save_isk;
+      curbuf->b_p_isk = (char *)save_isk;
     }
   }
   redraw_later(curwin, UPD_NOT_VALID);
@@ -5070,7 +5070,7 @@ static char_u *get_syn_pattern(char_u *arg, synpat_T *ci)
 
   // Make 'cpoptions' empty, to avoid the 'l' flag
   cpo_save = p_cpo;
-  p_cpo = (char *)empty_option;
+  p_cpo = empty_option;
   ci->sp_prog = vim_regcomp((char *)ci->sp_pattern, RE_MAGIC);
   p_cpo = cpo_save;
 
@@ -5226,14 +5226,14 @@ static void syn_cmd_sync(exarg_T *eap, int syncing)
       if (!eap->skip) {
         // store the pattern and compiled regexp program
         curwin->w_s->b_syn_linecont_pat =
-          vim_strnsave(next_arg + 1, (size_t)(arg_end - (char *)next_arg) - 1);
+          (char *)vim_strnsave(next_arg + 1, (size_t)(arg_end - (char *)next_arg) - 1);
         curwin->w_s->b_syn_linecont_ic = curwin->w_s->b_syn_ic;
 
         // Make 'cpoptions' empty, to avoid the 'l' flag
         cpo_save = p_cpo;
-        p_cpo = (char *)empty_option;
+        p_cpo = empty_option;
         curwin->w_s->b_syn_linecont_prog =
-          vim_regcomp((char *)curwin->w_s->b_syn_linecont_pat, RE_MAGIC);
+          vim_regcomp(curwin->w_s->b_syn_linecont_pat, RE_MAGIC);
         p_cpo = cpo_save;
         syn_clear_time(&curwin->w_s->b_syn_linecont_time);
 
diff --git a/src/nvim/tag.c b/src/nvim/tag.c
index 7401e73e84..ad00c3dafc 100644
--- a/src/nvim/tag.c
+++ b/src/nvim/tag.c
@@ -202,7 +202,7 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
   }
 
   prev_num_matches = num_matches;
-  free_string_option(nofile_fname);
+  free_string_option((char *)nofile_fname);
   nofile_fname = NULL;
 
   clearpos(&saved_fmark.mark);          // shutup gcc 4.0
@@ -215,7 +215,7 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
     new_tag = true;
     if (g_do_tagpreview != 0) {
       tagstack_clear_entry(&ptag_entry);
-      ptag_entry.tagname = vim_strsave(tag);
+      ptag_entry.tagname = (char *)vim_strsave(tag);
     }
   } else {
     if (g_do_tagpreview != 0) {
@@ -239,7 +239,7 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
           cur_fnum = ptag_entry.cur_fnum;
         } else {
           tagstack_clear_entry(&ptag_entry);
-          ptag_entry.tagname = vim_strsave(tag);
+          ptag_entry.tagname = (char *)vim_strsave(tag);
         }
       } else {
         /*
@@ -261,7 +261,7 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
         }
 
         // put the tag name in the tag stack
-        tagstack[tagstackidx].tagname = vim_strsave(tag);
+        tagstack[tagstackidx].tagname = (char *)vim_strsave(tag);
 
         curwin->w_tagstacklen = tagstacklen;
 
@@ -440,9 +440,9 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
 
     // When desired match not found yet, try to find it (and others).
     if (use_tagstack) {
-      name = tagstack[tagstackidx].tagname;
+      name = (char_u *)tagstack[tagstackidx].tagname;
     } else if (g_do_tagpreview != 0) {
-      name = ptag_entry.tagname;
+      name = (char_u *)ptag_entry.tagname;
     } else {
       name = tag;
     }
@@ -587,9 +587,9 @@ bool do_tag(char_u *tag, int type, int count, int forceit, int verbose)
         if (use_tfu && parse_match((char_u *)matches[cur_match], &tagp2) == OK
             && tagp2.user_data) {
           XFREE_CLEAR(tagstack[tagstackidx].user_data);
-          tagstack[tagstackidx].user_data = vim_strnsave(tagp2.user_data,
-                                                         (size_t)(tagp2.user_data_end -
-                                                                  tagp2.user_data));
+          tagstack[tagstackidx].user_data = (char *)vim_strnsave(tagp2.user_data,
+                                                                 (size_t)(tagp2.user_data_end -
+                                                                          tagp2.user_data));
         }
 
         tagstackidx++;
@@ -1184,7 +1184,7 @@ static int find_tagfunc_tags(char_u *pat, garray_T *ga, int *match_count, int fl
                flags & TAG_REGEXP   ? "r": "");
 
   save_pos = curwin->w_cursor;
-  result = call_vim_function((char *)curbuf->b_p_tfu, 3, args, &rettv);
+  result = call_vim_function(curbuf->b_p_tfu, 3, args, &rettv);
   curwin->w_cursor = save_pos;  // restore the cursor position
   d->dv_refcount--;
 
@@ -2388,7 +2388,7 @@ int get_tagfname(tagname_T *tnp, int first, char_u *buf)
   if (first) {
     // Init.  We make a copy of 'tags', because autocommands may change
     // the value without notifying us.
-    tnp->tn_tags = vim_strsave((*curbuf->b_p_tags != NUL) ? curbuf->b_p_tags : p_tags);
+    tnp->tn_tags = vim_strsave((*curbuf->b_p_tags != NUL) ? (char_u *)curbuf->b_p_tags : p_tags);
     tnp->tn_np = (char *)tnp->tn_tags;
   }
 
@@ -3365,7 +3365,7 @@ static void tagstack_push_item(win_T *wp, char_u *tagname, int cur_fnum, int cur
   }
 
   wp->w_tagstacklen++;
-  tagstack[idx].tagname = tagname;
+  tagstack[idx].tagname = (char *)tagname;
   tagstack[idx].cur_fnum = cur_fnum;
   tagstack[idx].cur_match = cur_match;
   if (tagstack[idx].cur_match < 0) {
@@ -3373,7 +3373,7 @@ static void tagstack_push_item(win_T *wp, char_u *tagname, int cur_fnum, int cur
   }
   tagstack[idx].fmark.mark = mark;
   tagstack[idx].fmark.fnum = fnum;
-  tagstack[idx].user_data = user_data;
+  tagstack[idx].user_data = (char *)user_data;
 }
 
 // Add a list of items to the tag stack in the specified window
diff --git a/src/nvim/terminal.c b/src/nvim/terminal.c
index 1b4ac12aa6..90966bcfad 100644
--- a/src/nvim/terminal.c
+++ b/src/nvim/terminal.c
@@ -418,7 +418,7 @@ bool terminal_enter(void)
   // placed at end of buffer to "follow" output. #11072
   handle_T save_curwin = curwin->handle;
   bool save_w_p_cul = curwin->w_p_cul;
-  char_u *save_w_p_culopt = NULL;
+  char *save_w_p_culopt = NULL;
   char_u save_w_p_culopt_flags = curwin->w_p_culopt_flags;
   int save_w_p_cuc = curwin->w_p_cuc;
   long save_w_p_so = curwin->w_p_so;
@@ -426,7 +426,7 @@ bool terminal_enter(void)
   if (curwin->w_p_cul && curwin->w_p_culopt_flags & CULOPT_NBR) {
     if (STRCMP(curwin->w_p_culopt, "number")) {
       save_w_p_culopt = curwin->w_p_culopt;
-      curwin->w_p_culopt = (char_u *)xstrdup("number");
+      curwin->w_p_culopt = xstrdup("number");
     }
     curwin->w_p_culopt_flags = CULOPT_NBR;
   } else {
diff --git a/src/nvim/testing.c b/src/nvim/testing.c
index e3ffe1c7d1..4a252dca3e 100644
--- a/src/nvim/testing.c
+++ b/src/nvim/testing.c
@@ -457,7 +457,7 @@ void f_assert_exception(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     ga_clear(&ga);
     rettv->vval.v_number = 1;
   } else if (error != NULL
-             && strstr((char *)get_vim_var_str(VV_EXCEPTION), error) == NULL) {
+             && strstr(get_vim_var_str(VV_EXCEPTION), error) == NULL) {
     prepare_assert_error(&ga);
     fill_assert_error(&ga, &argvars[1], NULL, &argvars[0],
                       get_vim_var_tv(VV_EXCEPTION), ASSERT_OTHER);
@@ -493,7 +493,7 @@ void f_assert_fails(typval_T *argvars, typval_T *rettv, EvalFuncData fptr)
     const char *const error = tv_get_string_buf_chk(&argvars[1], buf);
 
     if (error == NULL
-        || strstr((char *)get_vim_var_str(VV_ERRMSG), error) == NULL) {
+        || strstr(get_vim_var_str(VV_ERRMSG), error) == NULL) {
       prepare_assert_error(&ga);
       fill_assert_error(&ga, &argvars[2], NULL, &argvars[1],
                         get_vim_var_tv(VV_ERRMSG), ASSERT_OTHER);
diff --git a/src/nvim/undo.c b/src/nvim/undo.c
index e2e0bb38a2..ac52bce2f9 100644
--- a/src/nvim/undo.c
+++ b/src/nvim/undo.c
@@ -773,7 +773,7 @@ static bool serialize_header(bufinfo_T *bi, char_u *hash)
   undo_write_bytes(bi, (uintmax_t)buf->b_ml.ml_line_count, 4);
   size_t len = buf->b_u_line_ptr ? STRLEN(buf->b_u_line_ptr) : 0;
   undo_write_bytes(bi, len, 4);
-  if (len > 0 && !undo_write(bi, buf->b_u_line_ptr, len)) {
+  if (len > 0 && !undo_write(bi, (char_u *)buf->b_u_line_ptr, len)) {
     return false;
   }
   undo_write_bytes(bi, (uintmax_t)buf->b_u_line_lnum, 4);
@@ -1593,7 +1593,7 @@ void u_read_undo(char *name, const char_u *hash, const char_u *orig_name FUNC_AT
   curbuf->b_u_oldhead = old_idx < 0 ? NULL : uhp_table[old_idx];
   curbuf->b_u_newhead = new_idx < 0 ? NULL : uhp_table[new_idx];
   curbuf->b_u_curhead = cur_idx < 0 ? NULL : uhp_table[cur_idx];
-  curbuf->b_u_line_ptr = line_ptr;
+  curbuf->b_u_line_ptr = (char *)line_ptr;
   curbuf->b_u_line_lnum = line_lnum;
   curbuf->b_u_line_colnr = line_colnr;
   curbuf->b_u_numhead = num_head;
@@ -2960,7 +2960,7 @@ void u_saveline(linenr_T lnum)
   } else {
     curbuf->b_u_line_colnr = 0;
   }
-  curbuf->b_u_line_ptr = u_save_line(lnum);
+  curbuf->b_u_line_ptr = (char *)u_save_line(lnum);
 }
 
 /// clear the line saved for the "U" command
@@ -2992,12 +2992,12 @@ void u_undoline(void)
   }
 
   char_u *oldp = u_save_line(curbuf->b_u_line_lnum);
-  ml_replace(curbuf->b_u_line_lnum, (char *)curbuf->b_u_line_ptr, true);
+  ml_replace(curbuf->b_u_line_lnum, curbuf->b_u_line_ptr, true);
   changed_bytes(curbuf->b_u_line_lnum, 0);
   extmark_splice_cols(curbuf, (int)curbuf->b_u_line_lnum - 1, 0, (colnr_T)STRLEN(oldp),
                       (colnr_T)STRLEN(curbuf->b_u_line_ptr), kExtmarkUndo);
   xfree(curbuf->b_u_line_ptr);
-  curbuf->b_u_line_ptr = oldp;
+  curbuf->b_u_line_ptr = (char *)oldp;
 
   colnr_T t = curbuf->b_u_line_colnr;
   if (curwin->w_cursor.lnum == curbuf->b_u_line_lnum) {
diff --git a/src/nvim/version.c b/src/nvim/version.c
index 34ded3460f..0e0aac0354 100644
--- a/src/nvim/version.c
+++ b/src/nvim/version.c
@@ -2072,7 +2072,7 @@ void list_in_columns(char **items, int size, int current)
   // Find the length of the longest item, use that + 1 as the column width.
   int i;
   for (i = 0; size < 0 ? items[i] != NULL : i < size; i++) {
-    int l = vim_strsize((char *)items[i]) + (i == current ? 2 : 0);
+    int l = vim_strsize(items[i]) + (i == current ? 2 : 0);
 
     if (l > width) {
       width = l;
@@ -2084,7 +2084,7 @@ void list_in_columns(char **items, int size, int current)
   if (Columns < width) {
     // Not enough screen columns - show one per line
     for (i = 0; i < item_count; i++) {
-      version_msg_wrap((char *)items[i], i == current);
+      version_msg_wrap(items[i], i == current);
       if (msg_col > 0 && i < item_count - 1) {
         msg_putchar('\n');
       }
@@ -2106,7 +2106,7 @@ void list_in_columns(char **items, int size, int current)
       if (idx == current) {
         msg_putchar('[');
       }
-      msg_puts((char *)items[idx]);
+      msg_puts(items[idx]);
       if (idx == current) {
         msg_putchar(']');
       }
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 2a944e7d1d..aa275d1182 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -727,38 +727,38 @@ void win_set_minimal_style(win_T *wp)
 
   // Hide EOB region: use " " fillchar and cleared highlighting
   if (wp->w_p_fcs_chars.eob != ' ') {
-    char_u *old = wp->w_p_fcs;
+    char_u *old = (char_u *)wp->w_p_fcs;
     wp->w_p_fcs = ((*old == NUL)
-                   ? (char_u *)xstrdup("eob: ")
-                   : concat_str(old, (char_u *)",eob: "));
-    free_string_option(old);
+                   ? xstrdup("eob: ")
+                   : (char *)concat_str(old, (char_u *)",eob: "));
+    free_string_option((char *)old);
   }
 
   // TODO(bfredl): this could use a highlight namespace directly,
   // and avoid pecularities around window options
-  char_u *old = wp->w_p_winhl;
+  char_u *old = (char_u *)wp->w_p_winhl;
   wp->w_p_winhl = ((*old == NUL)
-                   ? (char_u *)xstrdup("EndOfBuffer:")
-                   : concat_str(old, (char_u *)",EndOfBuffer:"));
-  free_string_option(old);
+                   ? xstrdup("EndOfBuffer:")
+                   : (char *)concat_str(old, (char_u *)",EndOfBuffer:"));
+  free_string_option((char *)old);
   parse_winhl_opt(wp);
 
   // signcolumn: use 'auto'
   if (wp->w_p_scl[0] != 'a' || STRLEN(wp->w_p_scl) >= 8) {
     free_string_option(wp->w_p_scl);
-    wp->w_p_scl = (char_u *)xstrdup("auto");
+    wp->w_p_scl = xstrdup("auto");
   }
 
   // foldcolumn: use '0'
   if (wp->w_p_fdc[0] != '0') {
     free_string_option(wp->w_p_fdc);
-    wp->w_p_fdc = (char_u *)xstrdup("0");
+    wp->w_p_fdc = xstrdup("0");
   }
 
   // colorcolumn: cleared
   if (wp->w_p_cc != NULL && *wp->w_p_cc != NUL) {
     free_string_option(wp->w_p_cc);
-    wp->w_p_cc = (char_u *)xstrdup("");
+    wp->w_p_cc = xstrdup("");
   }
 }
 
@@ -1570,10 +1570,10 @@ static void win_init(win_T *newp, win_T *oldp, int flags)
     taggy_T *tag = &newp->w_tagstack[i];
     *tag = oldp->w_tagstack[i];
     if (tag->tagname != NULL) {
-      tag->tagname = vim_strsave(tag->tagname);
+      tag->tagname = xstrdup(tag->tagname);
     }
     if (tag->user_data != NULL) {
-      tag->user_data = vim_strsave(tag->user_data);
+      tag->user_data = xstrdup(tag->user_data);
     }
   }
   newp->w_tagstackidx = oldp->w_tagstackidx;
@@ -7291,7 +7291,7 @@ char *check_colorcolumn(win_T *wp)
     return NULL;      // buffer was closed
   }
 
-  for (s = (char *)wp->w_p_cc; *s != NUL && count < 255;) {
+  for (s = wp->w_p_cc; *s != NUL && count < 255;) {
     if (*s == '-' || *s == '+') {
       // -N and +N: add to 'textwidth'
       col = (*s == '-') ? -1 : 1;