xref: /llvm-project/clang/test/SemaCXX/coroutine-unreachable-warning.cpp (revision a73baf620b8374805b7e927cc79cc157a30e0ac8) 
1 // RUN: %clang_cc1 -triple x86_64-unknown-unknown %s -std=c++20 -fsyntax-only -verify -Wunreachable-code
2 
3 #include "Inputs/std-coroutine.h"
4 
5 extern void abort(void) __attribute__((__noreturn__));
6 
7 struct task {
8   struct promise_type {
9     std::suspend_always initial_suspend();
10     std::suspend_always final_suspend() noexcept;
11     void return_void();
yield_valuetask::promise_type12     std::suspend_always yield_value(int) { return {}; }
13     task get_return_object();
14     void unhandled_exception();
15 
16     struct Awaiter {
17       bool await_ready();
18       void await_suspend(auto);
19       int await_resume();
20     };
await_transformtask::promise_type21     auto await_transform(const int& x) { return Awaiter{}; }
22   };
23 };
24 
test1()25 task test1() {
26   abort();
27   co_yield 1;
28 }
29 
test2()30 task test2() {
31   abort();
32   1;  // expected-warning {{code will never be executed}}
33   co_yield 1;
34 }
35 
test3()36 task test3() {
37   abort();
38   co_return;
39 }
40 
test4()41 task test4() {
42   abort();
43   1;  // expected-warning {{code will never be executed}}
44   co_return;
45 }
46 
test5()47 task test5() {
48   abort();
49   co_await 1;
50 }
51 
test6()52 task test6() {
53   abort();
54   1;  // expected-warning {{code will never be executed}}
55   co_await 3;
56 }
57 
test7()58 task test7() {
59   // coroutine statements are not considered unreachable.
60   co_await 1;
61   abort();
62   co_await 2;
63 }
64 
test8()65 task test8() {
66   // coroutine statements are not considered unreachable.
67   abort();
68   co_return;
69   1 + 1;  // expected-warning {{code will never be executed}}
70 }
71 
test9()72 task test9() {
73   abort();
74   // This warning is emitted on the declaration itself, rather the coroutine substmt.
75   int x = co_await 1; // expected-warning {{code will never be executed}}
76 }
77