clang/test/C/C99/n835.c

   1 /* RUN: %clang_cc1 -verify -pedantic -std=c99 %s
   2    RUN: %clang_cc1 -verify=c89 -pedantic -std=c89 %s
   3    expected-no-diagnostics
   4  */
   5
   6 /* WG14 N835: Yes
   7  * Conversion of array to pointer not limited to lvalues
   8  *
   9  * NB: The crux of the change was C99 changing:
  10  *
  11  * C89 3.2.2.1: Except when it is the operand of ..., an lvalue that has type
  12  * 'array of type' is converted to an expression that has type 'pointer to
  13  * type' that points to the initial element of the array object and is not an
  14  * lvalue.
  15  *
  16  * C99 6.3.2.1p3: Except when it is the operand of ..., an expression that has
  17  * type 'array of type' is converted to an expression with type 'pointer to
  18  * type' that points to the initial element of the array object and is not an
  19  * lvalue.
  20  */
  21
  22 struct S {
  23   char arr[100];
  24 };
  25
  26 struct S f(void);
  27
  28 void func(void) {
  29   char c;
  30   /* The return from f() is an rvalue, so this code is not valid in C89, but is
  31    * valid in C99.
  32    */
  33   c = f().arr[10]; /* c89-warning {{ISO C90 does not allow subscripting non-lvalue array}} */
  34 }
  35