validate that reserved range start is before end; fix location information for existing similar check for enum reserved ranges

src/google/protobuf/compiler/parser.cc

@@ -1818,6 +1818,8 @@ bool Parser::ParseReservedNumbers(DescriptorProto* message,
     LocationRecorder location(parent_location, message->reserved_range_size());
 
     DescriptorProto::ReservedRange* range = message->add_reserved_range();
+    location.RecordLegacyLocation(range,
+                                  DescriptorPool::ErrorCollector::NUMBER);
     int start, end;
     io::Tokenizer::Token start_token;
     {
@@ -1895,6 +1897,8 @@ bool Parser::ParseReservedNumbers(EnumDescriptorProto* proto,
     LocationRecorder location(parent_location, proto->reserved_range_size());
 
     EnumDescriptorProto::EnumReservedRange* range = proto->add_reserved_range();
+    location.RecordLegacyLocation(range,
+                                  DescriptorPool::ErrorCollector::NUMBER);
     int start, end;
     io::Tokenizer::Token start_token;
     {

src/google/protobuf/compiler/parser_unittest.cc

@@ -2038,6 +2038,22 @@ TEST_F(ParserValidationErrorTest, ExtensionRangeNumberError) {
       "1:13: Suggested field numbers for Foo: 1\n");
 }
 
+TEST_F(ParserValidationErrorTest, ExtensionRangeNumberOrderError) {
+  ExpectHasValidationErrors(
+      "message Foo {\n"
+      "  extensions 2 to 1;\n"
+      "}\n",
+      "1:13: Extension range end number must be greater than start number.\n");
+}
+
+TEST_F(ParserValidationErrorTest, ReservedRangeError) {
+  ExpectHasValidationErrors(
+      "message Foo {\n"
+      "  reserved 2 to 1;\n"
+      "}\n",
+      "1:11: Reserved range end number must be greater than start number.\n");
+}
+
 TEST_F(ParserValidationErrorTest, Proto3ExtensionError) {
   ExpectHasValidationErrors(
       "syntax = 'proto3';\n"
@@ -2234,6 +2250,15 @@ TEST_F(ParserValidationErrorTest, EnumValueAliasError) {
       "definition. The next available enum value is 2.\n");
 }
 
+TEST_F(ParserValidationErrorTest, EnumReservedRangeError) {
+  ExpectHasValidationErrors(
+      "enum Foo {\n"
+      "  BAR = 1;\n"
+      "  reserved 2 to 1;\n"
+      "}\n",
+      "2:11: Reserved range end number must be greater than start number.\n");
+}
+
 TEST_F(ParserValidationErrorTest, ExplicitlyMapEntryError) {
   ExpectHasValidationErrors(
       "message Foo {\n"

src/google/protobuf/descriptor.cc

@@ -6677,6 +6677,10 @@ void DescriptorBuilder::BuildReservedRange(
     AddError(parent->full_name(), proto, DescriptorPool::ErrorCollector::NUMBER,
              "Reserved numbers must be positive integers.");
   }
+  if (result->start >= result->end) {
+    AddError(parent->full_name(), proto, DescriptorPool::ErrorCollector::NUMBER,
+             "Reserved range end number must be greater than start number.");
+  }
 }
 
 void DescriptorBuilder::BuildReservedRange(