https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109323
Bug ID: 109323 Summary: No error when neither of return_value or return_void is defined Product: gcc Version: 12.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: enricomaria.dean6elis at gmail dot com Target Milestone: --- Repro: 1. take the example here -> https://en.cppreference.com/w/cpp/language/coroutines 2. remove the 3 `if (cond) co_return;` from `fibonacci_sequence` 3. remove `return_void` from `promise_type` 4. compile Alternatively: https://godbolt.org/z/v3xd3b7TE, where both GCC and Clang erroneously accept the code, whereas MSVC correcly rejects it. (http://eel.is/c++draft/dcl.fct.def.coroutine#6) I'm aware of https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95517, but that makes no reference to the fact that not declaring any of the two functions is erroneous.