Un-revert "[coroutines][PR40978] Emit error for co_yield within catch block"


Un-revert "[coroutines][PR40978] Emit error for co_yield within catch block"

https://reviews.llvm.org/D59076 added a new coroutine error that
prevented users from using 'co_await' or 'co_yield' within a exception
handler. However, it was reverted in https://reviews.llvm.org/rC356774
because it caused a regression in nested scopes in C++ catch statements,
as documented by https://bugs.llvm.org/show_bug.cgi?id=41171.

The issue was due to an incorrect use of a clang::ParseScope. To fix:

  1. Add a regression test for catch statement parsing that mimics the bug report from https://bugs.llvm.org/show_bug.cgi?id=41171.
  2. Re-apply the coroutines error patch from https://reviews.llvm.org/D59076, but this time with the correct ParseScope behavior.

Reviewers: GorNishanov, tks2103, rsmith, riccibruno, jbulow

Reviewed By: riccibruno

Subscribers: EricWF, jdoerfert, lewissbaker, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D59752