diff --git a/src/google/protobuf/compiler/parser.cc b/src/google/protobuf/compiler/parser.cc
index 5d45741c6714..bb4951d0606e 100644
--- a/src/google/protobuf/compiler/parser.cc
+++ b/src/google/protobuf/compiler/parser.cc
@@ -571,6 +571,26 @@ void Parser::SkipRestOfBlock() {
 
 // ===================================================================
 
+bool Parser::ValidateMessage(const DescriptorProto* proto) {
+  for (int i = 0; i < proto->options().uninterpreted_option_size(); i++) {
+    const UninterpretedOption& option =
+        proto->options().uninterpreted_option(i);
+    if (option.name_size() > 0 && !option.name(0).is_extension() &&
+        option.name(0).name_part() == "map_entry") {
+      int line = -1, col = 0;  // indicates line and column not known
+      if (source_location_table_ != nullptr) {
+        source_location_table_->Find(
+            &option, DescriptorPool::ErrorCollector::OPTION_NAME, &line, &col);
+      }
+      RecordError(line, col,
+                  "map_entry should not be set explicitly. "
+                  "Use map<KeyType, ValueType> instead.");
+      return false;
+    }
+  }
+  return true;
+}
+
 bool Parser::ValidateEnum(const EnumDescriptorProto* proto) {
   bool has_allow_alias = false;
   bool allow_alias = false;
@@ -661,9 +681,8 @@ bool Parser::Parse(io::Tokenizer* input, FileDescriptorProto* file) {
     root_location.RecordLegacyLocation(file,
                                        DescriptorPool::ErrorCollector::OTHER);
 
-    if (require_syntax_identifier_ || LookingAt("syntax")
-        || LookingAt("edition")
-    ) {
+    if (require_syntax_identifier_ || LookingAt("syntax") ||
+        LookingAt("edition")) {
       if (!ParseSyntaxIdentifier(file, root_location)) {
         // Don't attempt to parse the file if we didn't recognize the syntax
         // identifier.
@@ -867,6 +886,7 @@ bool IsMessageSetWireFormatMessage(const DescriptorProto& message) {
   for (int i = 0; i < options.uninterpreted_option_size(); ++i) {
     const UninterpretedOption& uninterpreted = options.uninterpreted_option(i);
     if (uninterpreted.name_size() == 1 &&
+        !uninterpreted.name(0).is_extension() &&
         uninterpreted.name(0).name_part() == "message_set_wire_format" &&
         uninterpreted.identifier_value() == "true") {
       return true;
@@ -931,6 +951,9 @@ bool Parser::ParseMessageBlock(DescriptorProto* message,
   if (message->reserved_range_size() > 0) {
     AdjustReservedRangesWithMaxEndNumber(message);
   }
+
+  DO(ValidateMessage(message));
+
   return true;
 }
 
diff --git a/src/google/protobuf/compiler/parser.h b/src/google/protobuf/compiler/parser.h
index e68db1b9eabc..93367ab1f19a 100644
--- a/src/google/protobuf/compiler/parser.h
+++ b/src/google/protobuf/compiler/parser.h
@@ -534,6 +534,7 @@ class PROTOBUF_EXPORT Parser {
     return syntax_identifier_ == "proto3";
   }
 
+  bool ValidateMessage(const DescriptorProto* proto);
   bool ValidateEnum(const EnumDescriptorProto* proto);
 
   // =================================================================
diff --git a/src/google/protobuf/compiler/parser_unittest.cc b/src/google/protobuf/compiler/parser_unittest.cc
index 3c16aad4c8e7..c1bc49086961 100644
--- a/src/google/protobuf/compiler/parser_unittest.cc
+++ b/src/google/protobuf/compiler/parser_unittest.cc
@@ -171,6 +171,8 @@ class ParserTest : public testing::Test {
   // input.
   void ExpectHasEarlyExitErrors(const char* text, const char* expected_errors) {
     SetupParser(text);
+    SourceLocationTable source_locations;
+    parser_->RecordSourceLocationsTo(&source_locations);
     FileDescriptorProto file;
     EXPECT_FALSE(parser_->Parse(input_.get(), &file));
     EXPECT_EQ(expected_errors, error_collector_.text_);
@@ -1746,12 +1748,12 @@ TEST_F(ParseErrorTest, EnumReservedMissingQuotes) {
 
 TEST_F(ParseErrorTest, EnumReservedInvalidIdentifier) {
   ExpectHasWarnings(
-      R"pb(
+      R"(
       enum TestEnum {
         FOO = 1;
         reserved "foo bar";
       }
-      )pb",
+      )",
       "3:17: Reserved name \"foo bar\" is not a valid identifier.\n");
 }
 
@@ -1784,11 +1786,11 @@ TEST_F(ParseErrorTest, ReservedMissingQuotes) {
 
 TEST_F(ParseErrorTest, ReservedInvalidIdentifier) {
   ExpectHasWarnings(
-      R"pb(
+      R"(
       message Foo {
         reserved "foo bar";
       }
-      )pb",
+      )",
       "2:17: Reserved name \"foo bar\" is not a valid identifier.\n");
 }
 
@@ -2235,7 +2237,7 @@ TEST_F(ParserValidationErrorTest, EnumValueAliasError) {
 }
 
 TEST_F(ParserValidationErrorTest, ExplicitlyMapEntryError) {
-  ExpectHasValidationErrors(
+  ExpectHasErrors(
       "message Foo {\n"
       "  message ValueEntry {\n"
       "    option map_entry = true;\n"
@@ -2243,9 +2245,8 @@ TEST_F(ParserValidationErrorTest, ExplicitlyMapEntryError) {
       "    optional int32 value = 2;\n"
       "    extensions 99 to 999;\n"
       "  }\n"
-      "  repeated ValueEntry value = 1;\n"
       "}",
-      "7:11: map_entry should not be set explicitly. Use "
+      "2:11: map_entry should not be set explicitly. Use "
       "map<KeyType, ValueType> instead.\n");
 }
 
@@ -2950,7 +2951,7 @@ class SourceInfoTest : public ParserTest {
       }
     }
 
-      return false;
+    return false;
   }
 
  private:
@@ -4143,7 +4144,6 @@ TEST_F(ParseEditionsTest, FeaturesWithoutEditions) {
 }
 
 
-
 }  // anonymous namespace
 
 }  // namespace compiler