gcc/testsuite/gcc.dg/c23-attr-nodiscard-2.c

   1 /* Test C23 nodiscard attribute: invalid contexts.  */
   2 /* { dg-do compile } */
   3 /* { dg-options "-std=c23 -pedantic-errors" } */
   4
   5 /* This attribute is not valid on types other than their definitions,
   6    or on declarations other than function declarations, or on
   7    statements, or as an attribute-declaration.  */
   8
   9 [[nodiscard]]; /* { dg-error "ignored" } */
  10
  11 int [[nodiscard]] var; /* { dg-error "ignored" } */
  12
  13 int [[nodiscard ("reason")]] var2; /* { dg-error "ignored" } */
  14
  15 int array_with_nod_type[2] [[nodiscard]]; /* { dg-error "ignored" } */
  16
  17 void fn_with_nod_type () [[nodiscard]]; /* { dg-error "ignored" } */
  18
  19 int z = sizeof (int [[__nodiscard__]]); /* { dg-error "ignored" } */
  20
  21 [[nodiscard]] typedef int nod_int; /* { dg-error "can only be applied" } */
  22
  23 [[nodiscard]] int nvar; /* { dg-error "can only be applied" } */
  24
  25 struct s { int a; };
  26
  27 [[nodiscard]] typedef struct s nod_s; /* { dg-error "can only be applied" } */
  28
  29 struct t { [[nodiscard]] int b; }; /* { dg-error "can only be applied" } */
  30
  31 enum e { E [[nodiscard]] }; /* { dg-error "can only be applied" } */
  32
  33 void fx ([[nodiscard]] int p); /* { dg-error "can only be applied" } */
  34
  35 void
  36 f (void)
  37 {
  38   int a;
  39   [[nodiscard ("reason")]] int b = 1; /* { dg-error "can only be applied" } */
  40   [[nodiscard]]; /* { dg-error "ignored" } */
  41   [[nodiscard]] a = 1; /* { dg-error "ignored" } */
  42   [[nodiscard]] label: ; /* { dg-error "can only be applied" } */
  43   switch (var)
  44     {
  45       [[nodiscard]] case 1: ; /* { dg-error "can only be applied" } */
  46       [[nodiscard]] default: ; /* { dg-error "can only be applied" } */
  47     }
  48 }