clang/test/C/drs/dr209.c

   1 /* RUN: %clang_cc1 -std=c99 -ffreestanding -triple x86_64-unknown-linux -fsyntax-only -verify -pedantic -Wno-c11-extensions %s
   2    RUN: %clang_cc1 -std=c99 -ffreestanding -triple x86_64-unknown-win32 -fms-compatibility -fsyntax-only -verify -pedantic -Wno-c11-extensions %s
   3    RUN: %clang_cc1 -std=c11 -ffreestanding -fsyntax-only -verify -pedantic %s
   4    RUN: %clang_cc1 -std=c17 -ffreestanding -fsyntax-only -verify -pedantic %s
   5    RUN: %clang_cc1 -std=c2x -ffreestanding -fsyntax-only -verify -pedantic %s
   6  */
   7
   8 /* WG14 DR209: partial
   9  * Problem implementing INTN_C macros
  10  */
  11 #include <stdint.h>
  12
  13 #if INT8_C(0) != 0
  14 #error "uh oh"
  15 #elif INT16_C(0) != 0
  16 #error "uh oh"
  17 #elif INT32_C(0) != 0
  18 #error "uh oh"
  19 #elif INT64_C(0) != 0LL
  20 #error "uh oh"
  21 #elif UINT8_C(0) != 0U
  22 #error "uh oh"
  23 #elif UINT16_C(0) != 0U
  24 #error "uh oh"
  25 #elif UINT32_C(0) != 0U
  26 #error "uh oh"
  27 #elif UINT64_C(0) != 0ULL
  28 #error "uh oh"
  29 #endif
  30
  31 void dr209(void) {
  32   (void)_Generic(INT8_C(0), __typeof__(+(int_least8_t){0}) : 1);
  33   (void)_Generic(INT16_C(0), __typeof__(+(int_least16_t){0}) : 1);
  34   (void)_Generic(INT32_C(0), __typeof__(+(int_least32_t){0}) : 1);
  35   (void)_Generic(INT64_C(0), __typeof__(+(int_least64_t){0}) : 1);
  36   // FIXME: This is not the expected behavior; the type of the expanded value
  37   // in both of these cases should be 'int',
  38   //
  39   // C99 7.18.4p3: The type of the expression shall have the same type as would
  40   // an expression of the corresponding type converted according to the integer
  41   // promotions.
  42   //
  43   // C99 7.18.4.1p1: The macro UINTN_C(value) shall expand to an integer
  44   // constant expression corresponding to the type uint_leastN_t.
  45   //
  46   // C99 7.18.1.2p2: The typedef name uint_leastN_t designates an unsigned
  47   // integer type with a width of at least N, ...
  48   //
  49   // So the value's type is the same underlying type as uint_leastN_t, which is
  50   // unsigned char for uint_least8_t, and unsigned short for uint_least16_t,
  51   // but then the value undergoes integer promotions which would convert both
  52   // of those types to int.
  53   //
  54   (void)_Generic(UINT8_C(0), __typeof__(+(uint_least8_t){0}) : 1);
  55   (void)_Generic(UINT16_C(0), __typeof__(+(uint_least16_t){0}) : 1);
  56   // expected-error@-2 {{controlling expression type 'unsigned int' not compatible with any generic association type}}
  57   // expected-error@-2 {{controlling expression type 'unsigned int' not compatible with any generic association type}}
  58   (void)_Generic(UINT32_C(0), __typeof__(+(uint_least32_t){0}) : 1);
  59   (void)_Generic(UINT64_C(0), __typeof__(+(uint_least64_t){0}) : 1);
  60 }
  61