8 files changed, 13 insertions, 10 deletions
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 9dde62f0ee..787b6addc9 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -2960,7 +2960,7 @@ void nvim_set_decoration_provider(Integer ns_id, DictionaryOf(LuaRef) opts,
     String k = opts.items[i].key;
     Object *v = &opts.items[i].value;
     size_t j;
-    for (j = 0; cbs[j].name; j++) {
+    for (j = 0; cbs[j].name && cbs[j].dest; j++) {
       if (strequal(cbs[j].name, k.data)) {
         if (v->type != kObjectTypeLuaRef) {
           api_set_error(err, kErrorTypeValidation,
diff --git a/src/nvim/ex_cmds2.c b/src/nvim/ex_cmds2.c
index c4c18c4324..cc0ec71627 100644
--- a/src/nvim/ex_cmds2.c
+++ b/src/nvim/ex_cmds2.c
@@ -2535,7 +2535,7 @@ void ex_source(exarg_T *eap)
 
 static void cmd_source(char_u *fname, exarg_T *eap)
 {
-  if (*fname == NUL) {
+  if (eap != NULL && *fname == NUL) {
     cmd_source_buffer(eap);
   } else if (eap != NULL && eap->forceit) {
     // ":source!": read Normal mode commands
@@ -2575,7 +2575,8 @@ static char_u *get_buffer_line(int c, void *cookie, int indent, bool do_concat)
   return (char_u *)xstrdup((const char *)curr_line);
 }
 
-static void cmd_source_buffer(exarg_T *eap)
+static void cmd_source_buffer(const exarg_T *eap)
+  FUNC_ATTR_NONNULL_ALL
 {
   GetBufferLineCookie cookie = {
       .curr_lnum = eap->line1,
diff --git a/src/nvim/ex_getln.c b/src/nvim/ex_getln.c
index 76df01c205..38385d19b2 100644
--- a/src/nvim/ex_getln.c
+++ b/src/nvim/ex_getln.c
@@ -4093,9 +4093,10 @@ ExpandOne (
   }
 
   if (mode == WILD_CANCEL) {
-    ss = vim_strsave(orig_save);
+    ss = vim_strsave(orig_save ? orig_save : (char_u *)"");
   } else if (mode == WILD_APPLY) {
-    ss =  vim_strsave(findex == -1 ? orig_save : xp->xp_files[findex]);
+    ss =  vim_strsave(findex == -1 ? (orig_save ? orig_save : (char_u *)"") :
+                      xp->xp_files[findex]);
   }
 
   /* free old names */
diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index 714bbb5780..65bd809436 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -4280,7 +4280,7 @@ char *modname(const char *fname, const char *ext, bool prepend_dot)
   if (fname == NULL || *fname == NUL) {
     retval = xmalloc(MAXPATHL + extlen + 3);  // +3 for PATHSEP, "_" (Win), NUL
     if (os_dirname((char_u *)retval, MAXPATHL) == FAIL
-        || (fnamelen = strlen(retval)) == 0) {
+        || strlen(retval) == 0) {
       xfree(retval);
       return NULL;
     }
diff --git a/src/nvim/message.c b/src/nvim/message.c
index dea6696f55..7c98d3c6b5 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -869,18 +869,18 @@ char_u *msg_trunc_attr(char_u *s, int force, int attr)
  */
 char_u *msg_may_trunc(int force, char_u *s)
 {
-  int n;
   int room;
 
   room = (int)(Rows - cmdline_row - 1) * Columns + sc_col - 1;
   if ((force || (shortmess(SHM_TRUNC) && !exmode_active))
-      && (n = (int)STRLEN(s) - room) > 0) {
+      && (int)STRLEN(s) - room > 0) {
     int size = vim_strsize(s);
 
     // There may be room anyway when there are multibyte chars.
     if (size <= room) {
       return s;
     }
+    int n;
     for (n = 0; size >= room; ) {
       size -= utf_ptr2cells(s + n);
       n += utfc_ptr2len(s + n);
diff --git a/src/nvim/mouse.c b/src/nvim/mouse.c
index fa9787a3ac..4c0339e5f4 100644
--- a/src/nvim/mouse.c
+++ b/src/nvim/mouse.c
@@ -748,7 +748,7 @@ int mouse_check_fold(void)
     }
   }
 
-  if (mouse_char == wp->w_p_fcs_chars.foldclosed) {
+  if (wp && mouse_char == wp->w_p_fcs_chars.foldclosed) {
     return MOUSE_FOLD_OPEN;
   } else if (mouse_char != ' ') {
     return MOUSE_FOLD_CLOSE;
diff --git a/src/nvim/ops.c b/src/nvim/ops.c
index 2d351f4dba..2cd71f2360 100644
--- a/src/nvim/ops.c
+++ b/src/nvim/ops.c
@@ -2807,7 +2807,7 @@ void do_put(int regname, yankreg_T *reg, int dir, long count, int flags)
   size_t y_size;
   size_t oldlen;
   int y_width = 0;
-  colnr_T vcol;
+  colnr_T vcol = 0;
   int delcount;
   int incr = 0;
   struct block_def bd;
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index 760a54a316..5bf5a471c1 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -3154,6 +3154,7 @@ static int win_line(win_T *wp, linenr_T lnum, int startrow, int endrow,
           mb_utf8 = false;
         }
       } else {
+        assert(p_extra != NULL);
         c = *p_extra;
         mb_c = c;
         // If the UTF-8 character is more than one byte: