clang/test/Sema/c2x-fallthrough.c

   1 // RUN: %clang_cc1 -fsyntax-only -fdouble-square-bracket-attributes -verify %s
   2
   3 void f(int n) {
   4   switch (n) {
   5   case 0:
   6     n += 1;
   7     [[fallthrough]]; // ok
   8   case 1:
   9     if (n) {
  10       [[fallthrough]]; // ok
  11     } else {
  12       return;
  13     }
  14   case 2:
  15     for (int n = 0; n != 10; ++n)
  16       [[fallthrough]]; // expected-error {{does not directly precede switch label}}
  17   case 3:
  18     while (1)
  19       [[fallthrough]]; // expected-error {{does not directly precede switch label}}
  20   case 4:
  21     while (0)
  22       [[fallthrough]]; // expected-error {{does not directly precede switch label}}
  23   case 5:
  24     do [[fallthrough]]; while (1); // expected-error {{does not directly precede switch label}}
  25   case 6:
  26     do [[fallthrough]]; while (0); // expected-error {{does not directly precede switch label}}
  27   case 7:
  28     switch (n) {
  29     case 0:
  30       // FIXME: This should be an error, even though the next thing we do is to
  31       // fall through in an outer switch statement.
  32       [[fallthrough]];
  33     }
  34   case 8:
  35     [[fallthrough]]; // expected-error {{does not directly precede switch label}}
  36     goto label;
  37   label:
  38   case 9:
  39     n += 1;
  40   case 10: // no warning, -Wimplicit-fallthrough is not enabled in this test, and does not need to
  41            // be enabled for these diagnostics to be produced.
  42     break;
  43   }
  44 }
  45
  46 [[fallthrough]] typedef int n1; // expected-error {{'fallthrough' attribute cannot be applied to a declaration}}
  47 typedef int [[fallthrough]] n2; // expected-error {{'fallthrough' attribute cannot be applied to types}}
  48 typedef int n3 [[fallthrough]]; // expected-error {{'fallthrough' attribute cannot be applied to a declaration}}
  49
  50 enum [[fallthrough]] E { // expected-error {{'fallthrough' attribute cannot be applied to a declaration}}
  51   One
  52 };
  53 struct [[fallthrough]] S { // expected-error {{'fallthrough' attribute cannot be applied to a declaration}}
  54   int i;
  55 };
  56
  57 [[fallthrough]] // expected-error {{'fallthrough' attribute cannot be applied to a declaration}}
  58 void g(void) {
  59   [[fallthrough]] int n; // expected-error {{'fallthrough' attribute cannot be applied to a declaration}}
  60   [[fallthrough]] ++n; // expected-error {{'fallthrough' attribute only applies to empty statements}}
  61
  62   switch (n) {
  63     // FIXME: This should be an error.
  64     [[fallthrough]];
  65     return;
  66
  67   case 0:
  68     [[fallthrough, fallthrough]]; // ok
  69   case 1:
  70     [[fallthrough(0)]]; // expected-error {{argument list}}
  71   case 2:
  72     break;
  73   }
  74 }
  75