[coroutines] Improved diagnostics when unhandled_exception is missing in the promise_type

Summary: Now we helpfully provide a note pointing at the promise_type in question.

Reviewers: EricWF, GorNishanov

Reviewed By: GorNishanov

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D33481

llvm-svn: 303752
diff --git a/clang/test/SemaCXX/coroutines.cpp b/clang/test/SemaCXX/coroutines.cpp
index 3e33c99..a39ad1b 100644
--- a/clang/test/SemaCXX/coroutines.cpp
+++ b/clang/test/SemaCXX/coroutines.cpp
@@ -540,7 +540,7 @@
 }
 template coro<bad_promise_6> bad_implicit_return_dependent(bad_promise_6); // expected-note {{in instantiation}}
 
-struct bad_promise_7 {
+struct bad_promise_7 { // expected-note 2 {{defined here}}
   coro<bad_promise_7> get_return_object();
   suspend_always initial_suspend();
   suspend_always final_suspend();