build: enable -Wshadow

Note about shada.c:
- shada_read_next_item_start was intentionally shadowing `unpacked` and
  `i` because many of the macros (e.g. ADDITIONAL_KEY) implicitly
  depended on those variable names.
- Macros were changed to parameterize `unpacked` (but not `i`). Macros
  like CLEAR_GA_AND_ERROR_OUT do control-flow (goto), so any other
  approach is messy.

1 files changed, 3 insertions, 4 deletions

diff --git a/src/nvim/fileio.c b/src/nvim/fileio.c
index fe12a69801..c631057e81 100644
--- a/src/nvim/fileio.c
+++ b/src/nvim/fileio.c
@@ -5997,9 +5997,8 @@ void do_autocmd(char_u *arg_in, int forceit)
   char_u      *pat;
   char_u      *envpat = NULL;
   char_u      *cmd;
-  event_T event;
-  int need_free = FALSE;
-  int nested = FALSE;
+  int need_free = false;
+  int nested = false;
   int group;
 
   if (*arg == '|') {
@@ -6082,7 +6081,7 @@ void do_autocmd(char_u *arg_in, int forceit)
   last_event = (event_T)-1;             // for listing the event name
   last_group = AUGROUP_ERROR;           // for listing the group name
   if (*arg == '*' || *arg == NUL || *arg == '|') {
-    for (event = (event_T)0; (int)event < (int)NUM_EVENTS;
+    for (event_T event = (event_T)0; (int)event < (int)NUM_EVENTS;
          event = (event_T)((int)event + 1)) {
       if (do_autocmd_event(event, pat, nested, cmd, forceit, group) == FAIL) {
         break;