Implements ContainerEq.
diff --git a/include/gmock/gmock-matchers.h b/include/gmock/gmock-matchers.h
index 69879a4..9113d17 100644
--- a/include/gmock/gmock-matchers.h
+++ b/include/gmock/gmock-matchers.h
@@ -38,6 +38,7 @@
 #ifndef GMOCK_INCLUDE_GMOCK_GMOCK_MATCHERS_H_
 #define GMOCK_INCLUDE_GMOCK_GMOCK_MATCHERS_H_
 
+#include <algorithm>
 #include <ostream>  // NOLINT
 #include <sstream>
 #include <string>
@@ -1635,6 +1636,73 @@
   matcher.ExplainMatchResultTo(obj, os);
 }
 
+// Implements an equality matcher for any STL-style container whose elements
+// support ==. This matcher is like Eq(), but its failure explanations provide
+// more detailed information that is useful when the container is used as a set.
+// The failure message reports elements that are in one of the operands but not
+// the other. The failure messages do not report duplicate or out-of-order
+// elements in the containers (which don't properly matter to sets, but can
+// occur if the containers are vectors or lists, for example).
+//
+// Uses the container's const_iterator, value_type, operator ==,
+// begin(), and end().
+template <typename Container>
+class ContainerEqMatcher {
+ public:
+  explicit ContainerEqMatcher(const Container& rhs) : rhs_(rhs) {}
+  bool Matches(const Container& lhs) const { return lhs == rhs_; }
+  void DescribeTo(::std::ostream* os) const {
+    *os << "equals ";
+    UniversalPrinter<Container>::Print(rhs_, os);
+  }
+  void DescribeNegationTo(::std::ostream* os) const {
+    *os << "does not equal ";
+    UniversalPrinter<Container>::Print(rhs_, os);
+  }
+
+  void ExplainMatchResultTo(const Container& lhs,
+                            ::std::ostream* os) const {
+    // Something is different. Check for missing values first.
+    bool printed_header = false;
+    for (typename Container::const_iterator it = lhs.begin();
+         it != lhs.end(); ++it) {
+      if (std::find(rhs_.begin(), rhs_.end(), *it) == rhs_.end()) {
+        if (printed_header) {
+          *os << ", ";
+        } else {
+          *os << "Only in actual: ";
+          printed_header = true;
+        }
+        UniversalPrinter<typename Container::value_type>::Print(*it, os);
+      }
+    }
+
+    // Now check for extra values.
+    bool printed_header2 = false;
+    for (typename Container::const_iterator it = rhs_.begin();
+         it != rhs_.end(); ++it) {
+      if (std::find(lhs.begin(), lhs.end(), *it) == lhs.end()) {
+        if (printed_header2) {
+          *os << ", ";
+        } else {
+          *os << (printed_header ? "; not" : "Not") << " in actual: ";
+          printed_header2 = true;
+        }
+        UniversalPrinter<typename Container::value_type>::Print(*it, os);
+      }
+    }
+  }
+ private:
+  const Container rhs_;
+};
+
+template <typename Container>
+void ExplainMatchResultTo(const ContainerEqMatcher<Container>& matcher,
+                          const Container& lhs,
+                          ::std::ostream* os) {
+  matcher.ExplainMatchResultTo(lhs, os);
+}
+
 }  // namespace internal
 
 // Implements MatcherCast().
@@ -2073,6 +2141,16 @@
   return MakePolymorphicMatcher(internal::TrulyMatcher<Predicate>(pred));
 }
 
+// Returns a matcher that matches an equal container.
+// This matcher behaves like Eq(), but in the event of mismatch lists the
+// values that are included in one container but not the other. (Duplicate
+// values and order differences are not explained.)
+template <typename Container>
+inline PolymorphicMatcher<internal::ContainerEqMatcher<Container> >
+    ContainerEq(const Container& rhs) {
+  return MakePolymorphicMatcher(internal::ContainerEqMatcher<Container>(rhs));
+}
+
 // Returns a predicate that is satisfied by anything that matches the
 // given matcher.
 template <typename M>
diff --git a/test/gmock-matchers_test.cc b/test/gmock-matchers_test.cc
index 29b038e..e9d12b2 100644
--- a/test/gmock-matchers_test.cc
+++ b/test/gmock-matchers_test.cc
@@ -37,8 +37,12 @@
 
 #include <string.h>
 #include <functional>
-#include <string>
+#include <list>
+#include <map>
+#include <set>
 #include <sstream>
+#include <string>
+#include <vector>
 #include <gmock/gmock.h>
 #include <gtest/gtest.h>
 #include <gtest/gtest-spi.h>
@@ -2625,5 +2629,145 @@
   EXPECT_TRUE(m.Matches(n2));
 }
 
+// Tests ContainerEq with different container types, and
+// different element types.
+
+template <typename T>
+class ContainerEqTest : public testing::Test {
+ public:
+};
+
+typedef testing::Types<
+    std::set<int>,
+    std::vector<size_t>,
+    std::multiset<size_t>,
+    std::list<int> >
+    ContainerEqTestTypes;
+
+TYPED_TEST_CASE(ContainerEqTest, ContainerEqTestTypes);
+
+// Tests that the filled container is equal to itself.
+TYPED_TEST(ContainerEqTest, EqualsSelf) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  TypeParam my_set(vals, vals + 6);
+  const Matcher<TypeParam> m = ContainerEq(my_set);
+  EXPECT_TRUE(m.Matches(my_set));
+  EXPECT_EQ("", Explain(m, my_set));
+}
+
+// Tests that missing values are reported.
+TYPED_TEST(ContainerEqTest, ValueMissing) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {2, 1, 8, 5};
+  TypeParam my_set(vals, vals + 6);
+  TypeParam test_set(test_vals, test_vals + 4);
+  const Matcher<TypeParam> m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ("Not in actual: 3", Explain(m, test_set));
+}
+
+// Tests that added values are reported.
+TYPED_TEST(ContainerEqTest, ValueAdded) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 3, 5, 8, 46};
+  TypeParam my_set(vals, vals + 6);
+  TypeParam test_set(test_vals, test_vals + 6);
+  const Matcher<const TypeParam&> m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ("Only in actual: 46", Explain(m, test_set));
+}
+
+// Tests that added and missing values are reported together.
+TYPED_TEST(ContainerEqTest, ValueAddedAndRemoved) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 3, 8, 46};
+  TypeParam my_set(vals, vals + 6);
+  TypeParam test_set(test_vals, test_vals + 5);
+  const Matcher<TypeParam> m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ("Only in actual: 46; not in actual: 5", Explain(m, test_set));
+}
+
+// Tests duplicated value -- expect no explanation.
+TYPED_TEST(ContainerEqTest, DuplicateDifference) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 3, 5, 8};
+  TypeParam my_set(vals, vals + 6);
+  TypeParam test_set(test_vals, test_vals + 5);
+  const Matcher<const TypeParam&> m = ContainerEq(my_set);
+  // Depending on the container, match may be true or false
+  // But in any case there should be no explanation.
+  EXPECT_EQ("", Explain(m, test_set));
+}
+
+// Tests that mutliple missing values are reported.
+// Using just vector here, so order is predicatble.
+TEST(ContainerEqExtraTest, MultipleValuesMissing) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {2, 1, 5};
+  std::vector<int> my_set(vals, vals + 6);
+  std::vector<int> test_set(test_vals, test_vals + 3);
+  const Matcher<std::vector<int> > m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ("Not in actual: 3, 8", Explain(m, test_set));
+}
+
+// Tests that added values are reported.
+// Using just vector here, so order is predicatble.
+TEST(ContainerEqExtraTest, MultipleValuesAdded) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 92, 3, 5, 8, 46};
+  std::list<size_t> my_set(vals, vals + 6);
+  std::list<size_t> test_set(test_vals, test_vals + 7);
+  const Matcher<const std::list<size_t>&> m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ("Only in actual: 92, 46", Explain(m, test_set));
+}
+
+// Tests that added and missing values are reported together.
+TEST(ContainerEqExtraTest, MultipleValuesAddedAndRemoved) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 3, 92, 46};
+  std::list<size_t> my_set(vals, vals + 6);
+  std::list<size_t> test_set(test_vals, test_vals + 5);
+  const Matcher<const std::list<size_t> > m = ContainerEq(my_set);
+  EXPECT_FALSE(m.Matches(test_set));
+  EXPECT_EQ("Only in actual: 92, 46; not in actual: 5, 8",
+            Explain(m, test_set));
+}
+
+// Tests to see that duplicate elements are detected,
+// but (as above) not reported in the explanation.
+TEST(ContainerEqExtraTest, MultiSetOfIntDuplicateDifference) {
+  static const int vals[] = {1, 1, 2, 3, 5, 8};
+  static const int test_vals[] = {1, 2, 3, 5, 8};
+  std::vector<int> my_set(vals, vals + 6);
+  std::vector<int> test_set(test_vals, test_vals + 5);
+  const Matcher<std::vector<int> > m = ContainerEq(my_set);
+  EXPECT_TRUE(m.Matches(my_set));
+  EXPECT_FALSE(m.Matches(test_set));
+  // There is nothing to report when both sets contain all the same values.
+  EXPECT_EQ("", Explain(m, test_set));
+}
+
+// Tests that ContainerEq works for non-trivial associative containers,
+// like maps.
+TEST(ContainerEqExtraTest, WorksForMaps) {
+  std::map<int, std::string> my_map;
+  my_map[0] = "a";
+  my_map[1] = "b";
+
+  std::map<int, std::string> test_map;
+  test_map[0] = "aa";
+  test_map[1] = "b";
+
+  const Matcher<const std::map<int, std::string>&> m = ContainerEq(my_map);
+  EXPECT_TRUE(m.Matches(my_map));
+  EXPECT_FALSE(m.Matches(test_map));
+
+  EXPECT_EQ("Only in actual: (0, \"aa\"); not in actual: (0, \"a\")",
+            Explain(m, test_map));
+}
+
 }  // namespace gmock_matchers_test
 }  // namespace testing