clang/test/C/C99/block-scopes.c

   1 // RUN: %clang_cc1 -std=c89 -verify %s
   2 // RUN: %clang_cc1 -std=c99 -verify %s
   3 // RUN: %clang_cc1 -std=c11 -verify %s
   4 // RUN: %clang_cc1 -std=c17 -verify %s
   5 // RUN: %clang_cc1 -std=c23 -verify %s
   6
   7 // expected-no-diagnostics
   8
   9 /* WG14 ???: yes
  10  * new block scopes for selection and iteration statements
  11  *
  12  * This is referenced in the C99 front matter as new changes to C99, but it is
  13  * not clear which document number introduced the changes. It's possible this
  14  * is WG14 N759, based on discussion in the C99 rationale document that claims
  15  * these changes were made in response to surprising issues with the lifetime
  16  * of compound literals in compound statements vs non-compound statements.
  17  */
  18
  19 enum {a, b};
  20 void different(void) {
  21   if (sizeof(enum {b, a}) != sizeof(int)) {
  22     _Static_assert(a == 1, "");
  23   }
  24   /* In C89, the 'b' found here would have been from the enum declaration in
  25    * the controlling expression of the selection statement, not from the global
  26    * declaration. In C99 and later, that enumeration is scoped to the 'if'
  27    * statement and the global declaration is what's found.
  28    */
  29   #if __STDC_VERSION__ >= 199901L
  30     _Static_assert(b == 1, "");
  31   #else
  32     _Static_assert(b == 0, "");
  33   #endif
  34 }
  35