Fix isOverride() for the case of a dependent typed base class.

The method decl is not marked as overriding any other method decls
until the template is instantiated.
Use the override attribute as another signal.

llvm-svn: 231487
diff --git a/clang/unittests/ASTMatchers/ASTMatchersTest.cpp b/clang/unittests/ASTMatchers/ASTMatchersTest.cpp
index 0d27b5d..dab22e3 100644
--- a/clang/unittests/ASTMatchers/ASTMatchersTest.cpp
+++ b/clang/unittests/ASTMatchers/ASTMatchersTest.cpp
@@ -1790,6 +1790,9 @@
        methodDecl(isOverride())));
   EXPECT_TRUE(notMatches("class X { int f(); int f(int); }; ",
        methodDecl(isOverride())));
+  EXPECT_TRUE(
+      matches("template <typename Base> struct Y : Base { void f() override;};",
+              methodDecl(isOverride(), hasName("::Y::f"))));
 }
 
 TEST(Matcher, ConstructorCall) {