[ASTMatchers] New matcher hasReturnValue added

Summary: A checker (will be uploaded after this patch) needs to check implicit casts. Existing generic matcher "has" ignores implicit casts and parenthesized expressions and no specific matcher for matching return value expression preexisted. The patch adds such a matcher (hasReturnValue).

Reviewers: klimek, sbenza

Subscribers: xazax.hun, klimek, cfe-commits

Patch by Ádám Balogh!

Differential Revision: http://reviews.llvm.org/D17986

llvm-svn: 264037
diff --git a/clang/unittests/ASTMatchers/ASTMatchersTest.cpp b/clang/unittests/ASTMatchers/ASTMatchersTest.cpp
index 63dc1a8..713ef5a 100644
--- a/clang/unittests/ASTMatchers/ASTMatchersTest.cpp
+++ b/clang/unittests/ASTMatchers/ASTMatchersTest.cpp
@@ -5488,5 +5488,11 @@
   EXPECT_TRUE(notMatches("int i = 0;", expr(nullPointerConstant())));
 }
 
+TEST(StatementMatcher, HasReturnValue) {
+  StatementMatcher RetVal = returnStmt(hasReturnValue(binaryOperator()));
+  EXPECT_TRUE(matches("int F() { int a, b; return a + b; }", RetVal));
+  EXPECT_FALSE(matches("int F() { int a; return a; }", RetVal));
+}
+
 } // end namespace ast_matchers
 } // end namespace clang