1 files changed, 15 insertions, 11 deletions
diff --git a/googletest/include/gtest/gtest-matchers.h b/googletest/include/gtest/gtest-matchers.h
index 128fdb2f..846b9455 100644
--- a/googletest/include/gtest/gtest-matchers.h
+++ b/googletest/include/gtest/gtest-matchers.h
@@ -555,13 +555,12 @@ class PolymorphicMatcher {
   Impl impl_;
 };
 
-// Creates a matcher from its implementation.  This is easier to use
-// than the Matcher<T> constructor as it doesn't require you to
-// explicitly write the template argument, e.g.
+// Creates a matcher from its implementation.
+// DEPRECATED: Especially in the generic code, prefer:
+//   Matcher<T>(new MyMatcherImpl<const T&>(...));
 //
-//   MakeMatcher(foo);
-// vs
-//   Matcher<const string&>(foo);
+// MakeMatcher may create a Matcher that accepts its argument by value, which
+// leads to unnecessary copies & lack of support for non-copyable types.
 template <typename T>
 inline Matcher<T> MakeMatcher(const MatcherInterface<T>* impl) {
   return Matcher<T>(impl);
@@ -596,25 +595,30 @@ class ComparisonBase {
   explicit ComparisonBase(const Rhs& rhs) : rhs_(rhs) {}
   template <typename Lhs>
   operator Matcher<Lhs>() const {
-    return MakeMatcher(new Impl<Lhs>(rhs_));
+    return Matcher<Lhs>(new Impl<const Lhs&>(rhs_));
   }
 
  private:
-  template <typename Lhs>
+  template <typename T>
+  static const T& Unwrap(const T& v) { return v; }
+  template <typename T>
+  static const T& Unwrap(std::reference_wrapper<T> v) { return v; }
+
+  template <typename Lhs, typename = Rhs>
   class Impl : public MatcherInterface<Lhs> {
    public:
     explicit Impl(const Rhs& rhs) : rhs_(rhs) {}
     bool MatchAndExplain(Lhs lhs,
                          MatchResultListener* /* listener */) const override {
-      return Op()(lhs, rhs_);
+      return Op()(lhs, Unwrap(rhs_));
     }
     void DescribeTo(::std::ostream* os) const override {
       *os << D::Desc() << " ";
-      UniversalPrint(rhs_, os);
+      UniversalPrint(Unwrap(rhs_), os);
     }
     void DescribeNegationTo(::std::ostream* os) const override {
       *os << D::NegatedDesc() <<  " ";
-      UniversalPrint(rhs_, os);
+      UniversalPrint(Unwrap(rhs_), os);
     }
 
    private: