https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100127
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Iain D Sandoe <ia...@gcc.gnu.org>: https://gcc.gnu.org/g:2466a8d0dd40d05cb4a239d7d4a21bbd9ffab698 commit r12-6046-g2466a8d0dd40d05cb4a239d7d4a21bbd9ffab698 Author: Iain Sandoe <i...@sandoe.co.uk> Date: Sat Oct 2 17:20:08 2021 +0100 coroutines: Handle initial awaiters with non-void returns [PR 100127]. The way in which a C++20 coroutine is specified discards any value that might be returned from the initial or final await expressions. This ICE was caused by an initial await expression with an await_resume () returning a reference, the function rewrite code was not set up to expect this. Fixed by looking through any indirection present and by explicitly discarding the value, if any, returned by await_resume(). It does not seem useful to make a diagnostic for this, since the user could define a generic awaiter that usefully returns values when used in a different position from the initial (or final) await expressions. Signed-off-by: Iain Sandoe <i...@sandoe.co.uk> PR c++/100127 gcc/cp/ChangeLog: * coroutines.cc (coro_rewrite_function_body): Handle initial await expressions that try to produce a reference value. gcc/testsuite/ChangeLog: * g++.dg/coroutines/pr100127.C: New test.