diff --git a/lib/Rewrite/Frontend/RewriteModernObjC.cpp b/lib/Rewrite/Frontend/RewriteModernObjC.cpp
index caba62b118..03fd17f3da 100644
--- a/lib/Rewrite/Frontend/RewriteModernObjC.cpp
+++ b/lib/Rewrite/Frontend/RewriteModernObjC.cpp
@@ -939,9 +939,8 @@ void RewriteModernObjC::RewritePropertyImplDecl(ObjCPropertyImplDecl *PID,
   // Generate the 'getter' function.
   ObjCPropertyDecl *PD = PID->getPropertyDecl();
   ObjCIvarDecl *OID = PID->getPropertyIvarDecl();
+  assert(IMD && OID && "Synthesized ivars must be attached to @implementation");
 
-  if (!OID)
-    return;
   unsigned Attributes = PD->getPropertyAttributes();
   if (mustSynthesizeSetterGetterMethod(IMD, PD, true /*getter*/)) {
     bool GenGetProperty = !(Attributes & ObjCPropertyDecl::OBJC_PR_nonatomic) &&
diff --git a/lib/Sema/SemaExpr.cpp b/lib/Sema/SemaExpr.cpp
index dc6132ca9f..3af64bb9f1 100644
--- a/lib/Sema/SemaExpr.cpp
+++ b/lib/Sema/SemaExpr.cpp
@@ -3807,6 +3807,7 @@ bool Sema::GatherArgumentsForCall(SourceLocation CallLoc,
 
       Arg = ArgE.takeAs<Expr>();
     } else {
+      assert(FDecl && "can't use default arguments without a known callee");
       Param = FDecl->getParamDecl(i);
 
       ExprResult ArgExpr =