1 // RUN: %clang_cc1 -std=c++1z -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 (true) 19 [[fallthrough]]; // expected-error {{does not directly precede switch label}} 20 case 4: 21 while (false) 22 [[fallthrough]]; // expected-error {{does not directly precede switch label}} 23 case 5: 24 do [[fallthrough]]; while (true); // expected-error {{does not directly precede switch label}} 25 case 6: 26 do [[fallthrough]]; while (false); // 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 n; // expected-error {{'fallthrough' attribute cannot be applied to a declaration}} 47 typedef int [[fallthrough]] n; // expected-error {{'fallthrough' attribute cannot be applied to types}} 48 typedef int n [[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 class [[fallthrough]] C {}; // expected-error {{'fallthrough' attribute cannot be applied to a declaration}} 52 53 [[fallthrough]] // expected-error {{'fallthrough' attribute cannot be applied to a declaration}} 54 void g() { 55 [[fallthrough]] int n; // expected-error {{'fallthrough' attribute cannot be applied to a declaration}} 56 [[fallthrough]] ++n; // expected-error-re {{{{^}}fallthrough attribute is only allowed on empty statements}} 57 58 switch (n) { 59 // FIXME: This should be an error. 60 [[fallthrough]]; 61 return; 62 63 case 0: 64 [[fallthrough, fallthrough]]; // expected-error {{multiple times}} 65 case 1: 66 [[fallthrough(0)]]; // expected-error {{argument list}} 67 case 2: 68 break; 69 } 70 } 71
