https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111728
--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The releases/gcc-14 branch has been updated by Iain D Sandoe <ia...@gcc.gnu.org>: https://gcc.gnu.org/g:074a89e4c5f9b237176626d464fcc494389905f6 commit r14-11716-g074a89e4c5f9b237176626d464fcc494389905f6 Author: Arsen ArsenoviÄ <ar...@aarsen.me> Date: Thu Jul 18 18:16:49 2024 +0200 cp/coroutines: do not rewrite parameters in unevaluated contexts It is possible to use parameters of a parent function of a lambda in unevaluated contexts without capturing them. By not capturing them, we work around the usual mechanism we use to prevent rewriting captured parameters. Prevent this by simply skipping rewrites in unevaluated contexts. Those won't mind the value not being present anyway. This prevents an ICE during parameter substitution. In the testcase from the PR, the rewriting machinery finds a param in the body of the coroutine, which it did not previously encounter while processing the coroutine declaration, and that does not have a DECL_VALUE_EXPR, and fails. gcc/cp/ChangeLog: PR c++/111728 * coroutines.cc (rewrite_param_uses): Skip unevaluated subexpressions. gcc/testsuite/ChangeLog: PR c++/111728 * g++.dg/coroutines/pr111728.C: New test. (cherry picked from commit 1a37d6b732506f8c3f9e9452c9dc6a456f25397b)
