Fixes some warnings when compiled with MSVC at warning level 4.

include/gtest/gtest.h

@@ -614,10 +614,20 @@ AssertionResult CmpHelperEQ(const char* expected_expression,
                             const char* actual_expression,
                             const T1& expected,
                             const T2& actual) {
+#ifdef _MSC_VER
+#pragma warning(push)          // Saves the current warning state.
+#pragma warning(disable:4389)  // Temporarily disables warning on
+                               // signed/unsigned mismatch.
+#endif
+
   if (expected == actual) {
     return AssertionSuccess();
   }
 
+#ifdef _MSC_VER
+#pragma warning(pop)          // Restores the warning state.
+#endif
+
   return EqFailure(expected_expression,
                    actual_expression,
                    FormatForComparisonFailureMessage(expected, actual),
@@ -688,7 +698,7 @@ class EqHelper<true> {
   template <typename T1, typename T2>
   static AssertionResult Compare(const char* expected_expression,
                                  const char* actual_expression,
-                                 const T1& expected,
+                                 const T1& /* expected */,
                                  T2* actual) {
     // We already know that 'expected' is a null pointer.
     return CmpHelperEQ(expected_expression, actual_expression,
@@ -1315,7 +1325,7 @@ bool StaticAssertTypeEq() {
 // value, as it always calls GetTypeId<>() from the Google Test
 // framework.
 #define TEST(test_case_name, test_name)\
-  GTEST_TEST_(test_case_name, test_name,\
+  GTEST_TEST_(test_case_name, test_name, \
               ::testing::Test, ::testing::internal::GetTestTypeId())
 
 
@@ -1346,7 +1356,7 @@ bool StaticAssertTypeEq() {
 //   }
 
 #define TEST_F(test_fixture, test_name)\
-  GTEST_TEST_(test_fixture, test_name, test_fixture,\
+  GTEST_TEST_(test_fixture, test_name, test_fixture, \
               ::testing::internal::GetTypeId<test_fixture>())
 
 // Use this macro in main() to run all tests.  It returns 0 if all

include/gtest/internal/gtest-internal.h

@@ -748,6 +748,9 @@ String GetCurrentOsStackTraceExceptTop(UnitTest* unit_test, int skip_count);
 // Returns the number of failed test parts in the given test result object.
 int GetFailedPartCount(const TestResult* result);
 
+// A helper for suppressing warnings on unreachable code in some macros.
+inline bool True() { return true; }
+
 }  // namespace internal
 }  // namespace testing
 
@@ -835,7 +838,7 @@ int GetFailedPartCount(const TestResult* result);
   GTEST_AMBIGUOUS_ELSE_BLOCKER_ \
   if (const char* gtest_msg = "") { \
     ::testing::internal::HasNewFatalFailureHelper gtest_fatal_failure_checker; \
-    { statement; } \
+    if (::testing::internal::True()) { statement; } \
     if (gtest_fatal_failure_checker.has_new_fatal_failure()) { \
       gtest_msg = "Expected: " #statement " doesn't generate new fatal " \
                   "failures in the current thread.\n" \