Preserve the "last diagnostic was suppressed" flag across SFINAE checks.

Sometimes we check the validity of some construct between producing a
diagnostic and producing its notes. Ideally, we wouldn't do that, but in
practice running code that "cannot possibly produce a diagnostic" in such a
situation should be safe, and reasonable factoring of some code requires it
with our current diagnostics infrastruture. If this does happen, a diagnostic
that's suppressed due to SFINAE should not cause notes connected to the prior
diagnostic to be suppressed.

llvm-svn: 319408

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/test/SemaCXX/overload-call.cpp b/clang/test/SemaCXX/overload-call.cpp
index 0e3a9ee50bb..0c4bba5027f 100644
--- a/clang/test/SemaCXX/overload-call.cpp
+++ b/clang/test/SemaCXX/overload-call.cpp
@@ -658,3 +658,11 @@ namespace StringLiteralToCharAmbiguity {
   // expected-note@-5 {{candidate function}}
 #endif
 }
+
+namespace ProduceNotesAfterSFINAEFailure {
+  struct A {
+    template<typename T, typename U = typename T::x> A(T); // expected-warning 0-1{{extension}}
+  };
+  void f(void*, A); // expected-note {{candidate function not viable}}
+  void g() { f(1, 2); } // expected-error {{no matching function}}
+}