Make sure we correctly treat __is_convertible_to as an unevaluated context. PR11833.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148893 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 9 insertions, 2 deletions

diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 1b08aa2159..5c00e70af6 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -3166,8 +3166,9 @@ static bool EvaluateBinaryTypeTrait(Sema &Self, BinaryTypeTrait BTT,
     InitializationKind Kind(InitializationKind::CreateCopy(KeyLoc, 
                                                            SourceLocation()));
     
-    // Perform the initialization within a SFINAE trap at translation unit 
-    // scope.
+    // Perform the initialization in an unevaluated context within a SFINAE 
+    // trap at translation unit scope.
+    EnterExpressionEvaluationContext Unevaluated(Self, Sema::Unevaluated);
     Sema::SFINAETrap SFINAE(Self, /*AccessCheckingSFINAE=*/true);
     Sema::ContextRAII TUContext(Self, Self.Context.getTranslationUnitDecl());
     InitializationSequence Init(Self, To, Kind, &FromPtr, 1);
diff --git a/test/SemaCXX/type-traits.cpp b/test/SemaCXX/type-traits.cpp
index 2b8714b5e0..c1783dab28 100644
--- a/test/SemaCXX/type-traits.cpp
+++ b/test/SemaCXX/type-traits.cpp
@@ -1543,6 +1543,12 @@ void is_convertible_to() {
   { int arr[T(__is_convertible_to(X0<int>, X0<float>))]; }
 }
 
+namespace is_convertible_to_instantiate {
+  // Make sure we don't try to instantiate the constructor.
+  template<int x> class A { A(int) { int a[x]; } };
+  int x = __is_convertible_to(int, A<-1>);
+}
+
 void is_trivial()
 {
   { int arr[T(__is_trivial(int))]; }