clang/test/Sema/c2x-maybe_unused.c

   1 // RUN: %clang_cc1 -fsyntax-only -Wunused -std=c2x -verify %s
   2
   3 // This is the latest version of maybe_unused that we support.
   4 _Static_assert(__has_c_attribute(maybe_unused) == 202106L);
   5
   6 struct [[maybe_unused]] S1 { // ok
   7   int a [[maybe_unused]];
   8 };
   9
  10 enum [[maybe_unused]] E1 {
  11   EnumVal [[maybe_unused]]
  12 };
  13
  14 [[maybe_unused]] void unused_func([[maybe_unused]] int parm) {
  15   typedef int maybe_unused_int [[maybe_unused]];
  16   [[maybe_unused]] int I;
  17 }
  18
  19 void f1(void) {
  20   int x; // expected-warning {{unused variable}}
  21   typedef int I; // expected-warning {{unused typedef 'I'}}
  22
  23   // Should not warn about these due to not being used.
  24   [[maybe_unused]] int y;
  25   typedef int maybe_unused_int [[maybe_unused]];
  26
  27   // Should not warn about these uses.
  28   struct S1 s;
  29   maybe_unused_int test;
  30   y = 12;
  31 }
  32
  33 void f2(void);
  34 [[maybe_unused]] void f2(void);
  35
  36 void f2(void) {
  37 }
  38
  39 void label(void) {
  40   [[maybe_unused]] label:
  41   ;
  42
  43   other_label: // expected-warning {{unused label 'other_label'}}
  44   ;
  45 }