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

Summary:
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

llvm-svn: 356865

1 files changed, 3 insertions, 1 deletions

diff --git a/clang/lib/Sema/Scope.cpp b/clang/lib/Sema/Scope.cpp
index 09940688efa..51b0b24e57b 100644
--- a/clang/lib/Sema/Scope.cpp
+++ b/clang/lib/Sema/Scope.cpp
@@ -166,7 +166,9 @@ void Scope::dumpImpl(raw_ostream &OS) const {
       {SEHExceptScope, "SEHExceptScope"},
       {SEHFilterScope, "SEHFilterScope"},
       {CompoundStmtScope, "CompoundStmtScope"},
-      {ClassInheritanceScope, "ClassInheritanceScope"}};
+      {ClassInheritanceScope, "ClassInheritanceScope"},
+      {CatchScope, "CatchScope"},
+  };
 
   for (auto Info : FlagInfo) {
     if (Flags & Info.first) {