gcc/testsuite/gcc.dg/pr29521-2.c

/* PR 29521 : warning for return with expression in function returning void */
/* { dg-do compile } */
/* { dg-options "-pedantic-errors" } */

void func (void) { }

void func2 (void)
{
  return func (); /* { dg-error "ISO C forbids 'return' with expression" } */
}

void func3 (void)
{
  return 1; /* { dg-error "'return' with a value" } */
}