Enable safe matcher casts from Matcher<const T&> to Matcher<T>.

PiperOrigin-RevId: 715826130
Change-Id: Id962fd456f6da21ea2a909f331f92d814f1dad46

googlemock/test/gmock-matchers-comparisons_test.cc

@@ -411,9 +411,27 @@ class IntValue {
   int value_;
 };
 
+// For testing casting matchers between compatible types. This is similar to
+// IntValue, but takes a non-const reference to the value, showing MatcherCast
+// works with such types (and doesn't, for example, use a const ref internally).
+class MutableIntView {
+ public:
+  // An int& can be statically (although not implicitly) cast to a
+  // MutableIntView.
+  explicit MutableIntView(int& a_value) : value_(a_value) {}
+
+  int& value() const { return value_; }
+
+ private:
+  int& value_;
+};
+
 // For testing casting matchers between compatible types.
 bool IsPositiveIntValue(const IntValue& foo) { return foo.value() > 0; }
 
+// For testing casting matchers between compatible types.
+bool IsPositiveMutableIntView(MutableIntView foo) { return foo.value() > 0; }
+
 // Tests that MatcherCast<T>(m) works when m is a Matcher<U> where T
 // can be statically converted to U.
 TEST(MatcherCastTest, FromCompatibleType) {
@@ -429,14 +447,34 @@ TEST(MatcherCastTest, FromCompatibleType) {
   // predicate.
   EXPECT_TRUE(m4.Matches(1));
   EXPECT_FALSE(m4.Matches(0));
+
+  Matcher<MutableIntView> m5 = Truly(IsPositiveMutableIntView);
+  Matcher<int> m6 = MatcherCast<int>(m5);
+  // In the following, the arguments 1 and 0 are statically converted to
+  // MutableIntView objects, and then tested by the IsPositiveMutableIntView()
+  // predicate.
+  EXPECT_TRUE(m6.Matches(1));
+  EXPECT_FALSE(m6.Matches(0));
 }
 
 // Tests that MatcherCast<T>(m) works when m is a Matcher<const T&>.
 TEST(MatcherCastTest, FromConstReferenceToNonReference) {
-  Matcher<const int&> m1 = Eq(0);
+  int n = 0;
+  Matcher<const int&> m1 = Ref(n);
   Matcher<int> m2 = MatcherCast<int>(m1);
-  EXPECT_TRUE(m2.Matches(0));
-  EXPECT_FALSE(m2.Matches(1));
+  int n1 = 0;
+  EXPECT_TRUE(m2.Matches(n));
+  EXPECT_FALSE(m2.Matches(n1));
+}
+
+// Tests that MatcherCast<T&>(m) works when m is a Matcher<const T&>.
+TEST(MatcherCastTest, FromConstReferenceToReference) {
+  int n = 0;
+  Matcher<const int&> m1 = Ref(n);
+  Matcher<int&> m2 = MatcherCast<int&>(m1);
+  int n1 = 0;
+  EXPECT_TRUE(m2.Matches(n));
+  EXPECT_FALSE(m2.Matches(n1));
 }
 
 // Tests that MatcherCast<T>(m) works when m is a Matcher<T&>.
@@ -445,6 +483,12 @@ TEST(MatcherCastTest, FromReferenceToNonReference) {
   Matcher<int> m2 = MatcherCast<int>(m1);
   EXPECT_TRUE(m2.Matches(0));
   EXPECT_FALSE(m2.Matches(1));
+
+  // Of course, reference identity isn't preserved since a copy is required.
+  int n = 0;
+  Matcher<int&> m3 = Ref(n);
+  Matcher<int> m4 = MatcherCast<int>(m3);
+  EXPECT_FALSE(m4.Matches(n));
 }
 
 // Tests that MatcherCast<const T&>(m) works when m is a Matcher<T>.
@@ -649,6 +693,16 @@ TEST(SafeMatcherCastTest, FromBaseClass) {
   EXPECT_FALSE(m4.Matches(d2));
 }
 
+// Tests that SafeMatcherCast<T>(m) works when m is a Matcher<const T&>.
+TEST(SafeMatcherCastTest, FromConstReferenceToNonReference) {
+  int n = 0;
+  Matcher<const int&> m1 = Ref(n);
+  Matcher<int> m2 = SafeMatcherCast<int>(m1);
+  int n1 = 0;
+  EXPECT_TRUE(m2.Matches(n));
+  EXPECT_FALSE(m2.Matches(n1));
+}
+
 // Tests that SafeMatcherCast<T&>(m) works when m is a Matcher<const T&>.
 TEST(SafeMatcherCastTest, FromConstReferenceToReference) {
   int n = 0;

googlemock/test/gmock-matchers-misc_test.cc

@@ -32,6 +32,7 @@
 // This file tests some commonly used argument matchers.
 
 #include <array>
+#include <cstdint>
 #include <memory>
 #include <ostream>
 #include <string>
@@ -747,6 +748,24 @@ TYPED_TEST(OptionalTest, DoesNotMatchNullopt) {
   EXPECT_FALSE(m.Matches(empty));
 }
 
+TYPED_TEST(OptionalTest, ComposesWithMonomorphicMatchersTakingReferences) {
+  const Matcher<const int&> eq1 = Eq(1);
+  const Matcher<const int&> eq2 = Eq(2);
+  TypeParam opt(1);
+  EXPECT_THAT(opt, Optional(eq1));
+  EXPECT_THAT(opt, Optional(Not(eq2)));
+  EXPECT_THAT(opt, Optional(AllOf(eq1, Not(eq2))));
+}
+
+TYPED_TEST(OptionalTest, ComposesWithMonomorphicMatchersRequiringConversion) {
+  const Matcher<int64_t> eq1 = Eq(1);
+  const Matcher<int64_t> eq2 = Eq(2);
+  TypeParam opt(1);
+  EXPECT_THAT(opt, Optional(eq1));
+  EXPECT_THAT(opt, Optional(Not(eq2)));
+  EXPECT_THAT(opt, Optional(AllOf(eq1, Not(eq2))));
+}
+
 template <typename T>
 class MoveOnlyOptionalTest : public testing::Test {};