[Bug c/67854] Missing diagnostic for passing bool to va_arg

[slyfox at inbox dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67854

Sergei Trofimovich <slyfox at inbox dot ru> changed:

           What    |Removed                     |Added
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                 CC|                            |slyfox at inbox dot ru

--- Comment #4 from Sergei Trofimovich <slyfox at inbox dot ru> ---
Came up again in https://www.linux.org.ru/forum/development/12376493

The simplified test that which pre problem:

  typedef __builtin_va_list __gnuc_va_list;
  typedef __gnuc_va_list va_list;

  void func(va_list arg) {
    _Bool value = __builtin_va_arg(
                  arg
  //# 5 "a.c" 3 4
                  , _Bool);
    (void)value;
  }

  $ gcc-5.3.0 -c -O2 -Wall -Wextra a.c
  a.c: In function 'func':
  a.c:8:21: warning: '_Bool' is promoted to 'int' when passed through '...'
                     , _Bool);
                       ^
  a.c:8:21: note: (so you should pass 'int' not '_Bool' to 'va_arg')
  a.c:8:21: note: if this code is reached, the program will abort

If we uncomment line pragmas is stops working:

  typedef __builtin_va_list __gnuc_va_list;
  typedef __gnuc_va_list va_list;

  void func(va_list arg) {
    _Bool value = __builtin_va_arg(
                  arg
  # 5 "a.c" 3 4
                  , _Bool);
    (void)value;
  }

  $ gcc-5.3.0 -c -O2 -Wall -Wextra a.c

No warning.