Make __is_convertible_to handle abstract types correctly. PR13591.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@161828 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 21 insertions, 1 deletions

diff --git a/lib/Sema/SemaDeclCXX.cpp b/lib/Sema/SemaDeclCXX.cpp
index 539ed0eac5..1d45a6823d 100644
--- a/lib/Sema/SemaDeclCXX.cpp
+++ b/lib/Sema/SemaDeclCXX.cpp
@@ -3478,6 +3478,7 @@ bool Sema::RequireNonAbstractType(SourceLocation Loc, QualType T,
       : TypeDiagnoser(DiagID == 0), DiagID(DiagID), SelID(SelID) { }
     
     virtual void diagnose(Sema &S, SourceLocation Loc, QualType T) {
+      if (Suppressed) return;
       if (SelID == -1)
         S.Diag(Loc, DiagID) << T;
       else
diff --git a/lib/Sema/SemaExprCXX.cpp b/lib/Sema/SemaExprCXX.cpp
index 1a3cff5bd7..27402599a4 100644
--- a/lib/Sema/SemaExprCXX.cpp
+++ b/lib/Sema/SemaExprCXX.cpp
@@ -3542,9 +3542,25 @@ static bool EvaluateBinaryTypeTrait(Sema &Self, BinaryTypeTrait BTT,
     // We model the initialization as a copy-initialization of a temporary
     // of the appropriate type, which for this expression is identical to the
     // return statement (since NRVO doesn't apply).
+
+    // Functions aren't allowed to return function or array types.
+    if (RhsT->isFunctionType() || RhsT->isArrayType())
+      return false;
+
+    // A return statement in a void function must have void type.
+    if (RhsT->isVoidType())
+      return LhsT->isVoidType();
+
+    // A function definition requires a complete, non-abstract return type.
+    if (Self.RequireCompleteType(KeyLoc, RhsT, 0) ||
+        Self.RequireNonAbstractType(KeyLoc, RhsT, 0))
+      return false;
+
+    // Compute the result of add_rvalue_reference.
     if (LhsT->isObjectType() || LhsT->isFunctionType())
       LhsT = Self.Context.getRValueReferenceType(LhsT);
-    
+
+    // Build a fake source and destination for initialization.
     InitializedEntity To(InitializedEntity::InitializeTemporary(RhsT));
     OpaqueValueExpr From(KeyLoc, LhsT.getNonLValueExprType(Self.Context),
                          Expr::getValueKindForType(LhsT));
diff --git a/test/SemaCXX/type-traits.cpp b/test/SemaCXX/type-traits.cpp
index bf590f9c72..54294bcbb8 100644
--- a/test/SemaCXX/type-traits.cpp
+++ b/test/SemaCXX/type-traits.cpp
@@ -1574,6 +1574,8 @@ struct X0 {
   template<typename U> X0(const X0<U>&);
 };
 
+struct Abstract { virtual void f() = 0; };
+
 void is_convertible_to() {
   { int arr[T(__is_convertible_to(Int, Int))]; }
   { int arr[F(__is_convertible_to(Int, IntAr))]; }
@@ -1598,6 +1600,7 @@ void is_convertible_to() {
   { int arr[F(__is_convertible_to(Function, Function))]; }
   { int arr[F(__is_convertible_to(PrivateCopy, PrivateCopy))]; }
   { int arr[T(__is_convertible_to(X0<int>, X0<float>))]; }
+  { int arr[F(__is_convertible_to(Abstract, Abstract))]; }
 }
 
 namespace is_convertible_to_instantiate {