diff --git a/objectivec/Tests/unittest_objc.proto b/objectivec/Tests/unittest_objc.proto
index b0ab8d8991..1245ebefa0 100644
--- a/objectivec/Tests/unittest_objc.proto
+++ b/objectivec/Tests/unittest_objc.proto
@@ -409,6 +409,335 @@ message ObjCRetainedFoo {
   repeated Foo mutableCopy_Val_upper_enum_repeated = 724;
   repeated Foo mutableCopyvalue_lower_no_underscore_enum_repeated = 725;
   repeated Foo mutableCopyValue_upper_no_underscore_enum_repeated = 726;
+
+  extensions 1000 to 3999;
+}
+
+// Extension fields with retained names.
+extend ObjCRetainedFoo {
+  optional string new_val_lower_complex = 1011;
+  optional string new_Val_upper_complex = 1012;
+  optional string newvalue_lower_no_underscore_complex = 1013;
+  optional string newValue_upper_no_underscore_complex = 1014;
+
+  optional int32 new_val_lower_primitive = 1015;
+  optional int32 new_Val_upper_primitive = 1016;
+  optional int32 newvalue_lower_no_underscore_primitive = 1017;
+  optional int32 newValue_upper_no_underscore_primitive = 1018;
+
+  optional self new_val_lower_message = 1019;
+  optional self new_Val_upper_message = 1020;
+  optional self newvalue_lower_no_underscore_message = 1021;
+  optional self newValue_upper_no_underscore_message = 1022;
+
+  optional Foo new_val_lower_enum = 1023;
+  optional Foo new_Val_upper_enum = 1024;
+  optional Foo newvalue_lower_no_underscore_enum = 1025;
+  optional Foo newValue_upper_no_underscore_enum = 1026;
+
+  repeated string new_val_lower_complex_repeated = 1111;
+  repeated string new_Val_upper_complex_repeated = 1112;
+  repeated string newvalue_lower_no_underscore_complex_repeated = 1113;
+  repeated string newValue_upper_no_underscore_complex_repeated = 1114;
+
+  repeated int32 new_val_lower_primitive_repeated = 1115;
+  repeated int32 new_Val_upper_primitive_repeated = 1116;
+  repeated int32 newvalue_lower_no_underscore_primitive_repeated = 1117;
+  repeated int32 newValue_upper_no_underscore_primitive_repeated = 1118;
+
+  repeated self new_val_lower_message_repeated = 1119;
+  repeated self new_Val_upper_message_repeated = 1120;
+  repeated self newvalue_lower_no_underscore_message_repeated = 1121;
+  repeated self newValue_upper_no_underscore_message_repeated = 1122;
+
+  repeated Foo new_val_lower_enum_repeated = 1123;
+  repeated Foo new_Val_upper_enum_repeated = 1124;
+  repeated Foo newvalue_lower_no_underscore_enum_repeated = 1125;
+  repeated Foo newValue_upper_no_underscore_enum_repeated = 1126;
+
+  optional string alloc_val_lower_complex = 1211;
+  optional string alloc_Val_upper_complex = 1212;
+  optional string allocvalue_lower_no_underscore_complex = 1213;
+  optional string allocValue_upper_no_underscore_complex = 1214;
+
+  optional int32 alloc_val_lower_primitive = 1215;
+  optional int32 alloc_Val_upper_primitive = 1216;
+  optional int32 allocvalue_lower_no_underscore_primitive = 1217;
+  optional int32 allocValue_upper_no_underscore_primitive = 1218;
+
+  optional self alloc_val_lower_message = 1219;
+  optional self alloc_Val_upper_message = 1220;
+  optional self allocvalue_lower_no_underscore_message = 1221;
+  optional self allocValue_upper_no_underscore_message = 1222;
+
+  optional Foo alloc_val_lower_enum = 1223;
+  optional Foo alloc_Val_upper_enum = 1224;
+  optional Foo allocvalue_lower_no_underscore_enum = 1225;
+  optional Foo allocValue_upper_no_underscore_enum = 1226;
+
+  repeated string alloc_val_lower_complex_repeated = 1311;
+  repeated string alloc_Val_upper_complex_repeated = 1312;
+  repeated string allocvalue_lower_no_underscore_complex_repeated = 1313;
+  repeated string allocValue_upper_no_underscore_complex_repeated = 1314;
+
+  repeated int32 alloc_val_lower_primitive_repeated = 1315;
+  repeated int32 alloc_Val_upper_primitive_repeated = 1316;
+  repeated int32 allocvalue_lower_no_underscore_primitive_repeated = 1317;
+  repeated int32 allocValue_upper_no_underscore_primitive_repeated = 1318;
+
+  repeated self alloc_val_lower_message_repeated = 1319;
+  repeated self alloc_Val_upper_message_repeated = 1320;
+  repeated self allocvalue_lower_no_underscore_message_repeated = 1321;
+  repeated self allocValue_upper_no_underscore_message_repeated = 1322;
+
+  repeated Foo alloc_val_lower_enum_repeated = 1323;
+  repeated Foo alloc_Val_upper_enum_repeated = 1324;
+  repeated Foo allocvalue_lower_no_underscore_enum_repeated = 1325;
+  repeated Foo allocValue_upper_no_underscore_enum_repeated = 1326;
+
+  optional string copy_val_lower_complex = 1411;
+  optional string copy_Val_upper_complex = 1412;
+  optional string copyvalue_lower_no_underscore_complex = 1413;
+  optional string copyValue_upper_no_underscore_complex = 1414;
+
+  optional int32 copy_val_lower_primitive = 1415;
+  optional int32 copy_Val_upper_primitive = 1416;
+  optional int32 copyvalue_lower_no_underscore_primitive = 1417;
+  optional int32 copyValue_upper_no_underscore_primitive = 1418;
+
+  optional self copy_val_lower_message = 1419;
+  optional self copy_Val_upper_message = 1420;
+  optional self copyvalue_lower_no_underscore_message = 1421;
+  optional self copyValue_upper_no_underscore_message = 1422;
+
+  optional Foo copy_val_lower_enum = 1423;
+  optional Foo copy_Val_upper_enum = 1424;
+  optional Foo copyvalue_lower_no_underscore_enum = 1425;
+  optional Foo copyValue_upper_no_underscore_enum = 1426;
+
+  repeated string copy_val_lower_complex_repeated = 1511;
+  repeated string copy_Val_upper_complex_repeated = 1512;
+  repeated string copyvalue_lower_no_underscore_complex_repeated = 1513;
+  repeated string copyValue_upper_no_underscore_complex_repeated = 1514;
+
+  repeated int32 copy_val_lower_primitive_repeated = 1515;
+  repeated int32 copy_Val_upper_primitive_repeated = 1516;
+  repeated int32 copyvalue_lower_no_underscore_primitive_repeated = 1517;
+  repeated int32 copyValue_upper_no_underscore_primitive_repeated = 1518;
+
+  repeated self copy_val_lower_message_repeated = 1519;
+  repeated self copy_Val_upper_message_repeated = 1520;
+  repeated self copyvalue_lower_no_underscore_message_repeated = 1521;
+  repeated self copyValue_upper_no_underscore_message_repeated = 1522;
+
+  repeated Foo copy_val_lower_enum_repeated = 1523;
+  repeated Foo copy_Val_upper_enum_repeated = 1524;
+  repeated Foo copyvalue_lower_no_underscore_enum_repeated = 1525;
+  repeated Foo copyValue_upper_no_underscore_enum_repeated = 1526;
+
+  optional string mutableCopy_val_lower_complex = 1611;
+  optional string mutableCopy_Val_upper_complex = 1612;
+  optional string mutableCopyvalue_lower_no_underscore_complex = 1613;
+  optional string mutableCopyValue_upper_no_underscore_complex = 1614;
+
+  optional int32 mutableCopy_val_lower_primitive = 1615;
+  optional int32 mutableCopy_Val_upper_primitive = 1616;
+  optional int32 mutableCopyvalue_lower_no_underscore_primitive = 1617;
+  optional int32 mutableCopyValue_upper_no_underscore_primitive = 1618;
+
+  optional self mutableCopy_val_lower_message = 1619;
+  optional self mutableCopy_Val_upper_message = 1620;
+  optional self mutableCopyvalue_lower_no_underscore_message = 1621;
+  optional self mutableCopyValue_upper_no_underscore_message = 1622;
+
+  optional Foo mutableCopy_val_lower_enum = 1623;
+  optional Foo mutableCopy_Val_upper_enum = 1624;
+  optional Foo mutableCopyvalue_lower_no_underscore_enum = 1625;
+  optional Foo mutableCopyValue_upper_no_underscore_enum = 1626;
+
+  repeated string mutableCopy_val_lower_complex_repeated = 1711;
+  repeated string mutableCopy_Val_upper_complex_repeated = 1712;
+  repeated string mutableCopyvalue_lower_no_underscore_complex_repeated = 1713;
+  repeated string mutableCopyValue_upper_no_underscore_complex_repeated = 1714;
+
+  repeated int32 mutableCopy_val_lower_primitive_repeated = 1715;
+  repeated int32 mutableCopy_Val_upper_primitive_repeated = 1716;
+  repeated int32 mutableCopyvalue_lower_no_underscore_primitive_repeated = 1717;
+  repeated int32 mutableCopyValue_upper_no_underscore_primitive_repeated = 1718;
+
+  repeated self mutableCopy_val_lower_message_repeated = 1719;
+  repeated self mutableCopy_Val_upper_message_repeated = 1720;
+  repeated self mutableCopyvalue_lower_no_underscore_message_repeated = 1721;
+  repeated self mutableCopyValue_upper_no_underscore_message_repeated = 1722;
+
+  repeated Foo mutableCopy_val_lower_enum_repeated = 1723;
+  repeated Foo mutableCopy_Val_upper_enum_repeated = 1724;
+  repeated Foo mutableCopyvalue_lower_no_underscore_enum_repeated = 1725;
+  repeated Foo mutableCopyValue_upper_no_underscore_enum_repeated = 1726;
+}
+
+message JustToScopeExtensions {
+  extend ObjCRetainedFoo {
+    optional string new_val_lower_complex = 2011;
+    optional string new_Val_upper_complex = 2012;
+    optional string newvalue_lower_no_underscore_complex = 2013;
+    optional string newValue_upper_no_underscore_complex = 2014;
+
+    optional int32 new_val_lower_primitive = 2015;
+    optional int32 new_Val_upper_primitive = 2016;
+    optional int32 newvalue_lower_no_underscore_primitive = 2017;
+    optional int32 newValue_upper_no_underscore_primitive = 2018;
+
+    optional self new_val_lower_message = 2019;
+    optional self new_Val_upper_message = 2020;
+    optional self newvalue_lower_no_underscore_message = 2021;
+    optional self newValue_upper_no_underscore_message = 2022;
+
+    optional Foo new_val_lower_enum = 2023;
+    optional Foo new_Val_upper_enum = 2024;
+    optional Foo newvalue_lower_no_underscore_enum = 2025;
+    optional Foo newValue_upper_no_underscore_enum = 2026;
+
+    repeated string new_val_lower_complex_repeated = 2111;
+    repeated string new_Val_upper_complex_repeated = 2112;
+    repeated string newvalue_lower_no_underscore_complex_repeated = 2113;
+    repeated string newValue_upper_no_underscore_complex_repeated = 2114;
+
+    repeated int32 new_val_lower_primitive_repeated = 2115;
+    repeated int32 new_Val_upper_primitive_repeated = 2116;
+    repeated int32 newvalue_lower_no_underscore_primitive_repeated = 2117;
+    repeated int32 newValue_upper_no_underscore_primitive_repeated = 2118;
+
+    repeated self new_val_lower_message_repeated = 2119;
+    repeated self new_Val_upper_message_repeated = 2120;
+    repeated self newvalue_lower_no_underscore_message_repeated = 2121;
+    repeated self newValue_upper_no_underscore_message_repeated = 2122;
+
+    repeated Foo new_val_lower_enum_repeated = 2123;
+    repeated Foo new_Val_upper_enum_repeated = 2124;
+    repeated Foo newvalue_lower_no_underscore_enum_repeated = 2125;
+    repeated Foo newValue_upper_no_underscore_enum_repeated = 2126;
+
+    optional string alloc_val_lower_complex = 2211;
+    optional string alloc_Val_upper_complex = 2212;
+    optional string allocvalue_lower_no_underscore_complex = 2213;
+    optional string allocValue_upper_no_underscore_complex = 2214;
+
+    optional int32 alloc_val_lower_primitive = 2215;
+    optional int32 alloc_Val_upper_primitive = 2216;
+    optional int32 allocvalue_lower_no_underscore_primitive = 2217;
+    optional int32 allocValue_upper_no_underscore_primitive = 2218;
+
+    optional self alloc_val_lower_message = 2219;
+    optional self alloc_Val_upper_message = 2220;
+    optional self allocvalue_lower_no_underscore_message = 2221;
+    optional self allocValue_upper_no_underscore_message = 2222;
+
+    optional Foo alloc_val_lower_enum = 2223;
+    optional Foo alloc_Val_upper_enum = 2224;
+    optional Foo allocvalue_lower_no_underscore_enum = 2225;
+    optional Foo allocValue_upper_no_underscore_enum = 2226;
+
+    repeated string alloc_val_lower_complex_repeated = 2311;
+    repeated string alloc_Val_upper_complex_repeated = 2312;
+    repeated string allocvalue_lower_no_underscore_complex_repeated = 2313;
+    repeated string allocValue_upper_no_underscore_complex_repeated = 2314;
+
+    repeated int32 alloc_val_lower_primitive_repeated = 2315;
+    repeated int32 alloc_Val_upper_primitive_repeated = 2316;
+    repeated int32 allocvalue_lower_no_underscore_primitive_repeated = 2317;
+    repeated int32 allocValue_upper_no_underscore_primitive_repeated = 2318;
+
+    repeated self alloc_val_lower_message_repeated = 2319;
+    repeated self alloc_Val_upper_message_repeated = 2320;
+    repeated self allocvalue_lower_no_underscore_message_repeated = 2321;
+    repeated self allocValue_upper_no_underscore_message_repeated = 2322;
+
+    repeated Foo alloc_val_lower_enum_repeated = 2323;
+    repeated Foo alloc_Val_upper_enum_repeated = 2324;
+    repeated Foo allocvalue_lower_no_underscore_enum_repeated = 2325;
+    repeated Foo allocValue_upper_no_underscore_enum_repeated = 2326;
+
+    optional string copy_val_lower_complex = 2411;
+    optional string copy_Val_upper_complex = 2412;
+    optional string copyvalue_lower_no_underscore_complex = 2413;
+    optional string copyValue_upper_no_underscore_complex = 2414;
+
+    optional int32 copy_val_lower_primitive = 2415;
+    optional int32 copy_Val_upper_primitive = 2416;
+    optional int32 copyvalue_lower_no_underscore_primitive = 2417;
+    optional int32 copyValue_upper_no_underscore_primitive = 2418;
+
+    optional self copy_val_lower_message = 2419;
+    optional self copy_Val_upper_message = 2420;
+    optional self copyvalue_lower_no_underscore_message = 2421;
+    optional self copyValue_upper_no_underscore_message = 2422;
+
+    optional Foo copy_val_lower_enum = 2423;
+    optional Foo copy_Val_upper_enum = 2424;
+    optional Foo copyvalue_lower_no_underscore_enum = 2425;
+    optional Foo copyValue_upper_no_underscore_enum = 2426;
+
+    repeated string copy_val_lower_complex_repeated = 2511;
+    repeated string copy_Val_upper_complex_repeated = 2512;
+    repeated string copyvalue_lower_no_underscore_complex_repeated = 2513;
+    repeated string copyValue_upper_no_underscore_complex_repeated = 2514;
+
+    repeated int32 copy_val_lower_primitive_repeated = 2515;
+    repeated int32 copy_Val_upper_primitive_repeated = 2516;
+    repeated int32 copyvalue_lower_no_underscore_primitive_repeated = 2517;
+    repeated int32 copyValue_upper_no_underscore_primitive_repeated = 2518;
+
+    repeated self copy_val_lower_message_repeated = 2519;
+    repeated self copy_Val_upper_message_repeated = 2520;
+    repeated self copyvalue_lower_no_underscore_message_repeated = 2521;
+    repeated self copyValue_upper_no_underscore_message_repeated = 2522;
+
+    repeated Foo copy_val_lower_enum_repeated = 2523;
+    repeated Foo copy_Val_upper_enum_repeated = 2524;
+    repeated Foo copyvalue_lower_no_underscore_enum_repeated = 2525;
+    repeated Foo copyValue_upper_no_underscore_enum_repeated = 2526;
+
+    optional string mutableCopy_val_lower_complex = 2611;
+    optional string mutableCopy_Val_upper_complex = 2612;
+    optional string mutableCopyvalue_lower_no_underscore_complex = 2613;
+    optional string mutableCopyValue_upper_no_underscore_complex = 2614;
+
+    optional int32 mutableCopy_val_lower_primitive = 2615;
+    optional int32 mutableCopy_Val_upper_primitive = 2616;
+    optional int32 mutableCopyvalue_lower_no_underscore_primitive = 2617;
+    optional int32 mutableCopyValue_upper_no_underscore_primitive = 2618;
+
+    optional self mutableCopy_val_lower_message = 2619;
+    optional self mutableCopy_Val_upper_message = 2620;
+    optional self mutableCopyvalue_lower_no_underscore_message = 2621;
+    optional self mutableCopyValue_upper_no_underscore_message = 2622;
+
+    optional Foo mutableCopy_val_lower_enum = 2623;
+    optional Foo mutableCopy_Val_upper_enum = 2624;
+    optional Foo mutableCopyvalue_lower_no_underscore_enum = 2625;
+    optional Foo mutableCopyValue_upper_no_underscore_enum = 2626;
+
+    repeated string mutableCopy_val_lower_complex_repeated = 2711;
+    repeated string mutableCopy_Val_upper_complex_repeated = 2712;
+    repeated string mutableCopyvalue_lower_no_underscore_complex_repeated = 2713;
+    repeated string mutableCopyValue_upper_no_underscore_complex_repeated = 2714;
+
+    repeated int32 mutableCopy_val_lower_primitive_repeated = 2715;
+    repeated int32 mutableCopy_Val_upper_primitive_repeated = 2716;
+    repeated int32 mutableCopyvalue_lower_no_underscore_primitive_repeated = 2717;
+    repeated int32 mutableCopyValue_upper_no_underscore_primitive_repeated = 2718;
+
+    repeated self mutableCopy_val_lower_message_repeated = 2719;
+    repeated self mutableCopy_Val_upper_message_repeated = 2720;
+    repeated self mutableCopyvalue_lower_no_underscore_message_repeated = 2721;
+    repeated self mutableCopyValue_upper_no_underscore_message_repeated = 2722;
+
+    repeated Foo mutableCopy_val_lower_enum_repeated = 2723;
+    repeated Foo mutableCopy_Val_upper_enum_repeated = 2724;
+    repeated Foo mutableCopyvalue_lower_no_underscore_enum_repeated = 2725;
+    repeated Foo mutableCopyValue_upper_no_underscore_enum_repeated = 2726;
+  }
 }
 
 // Test handling of fields that are the retained names.
diff --git a/src/google/protobuf/compiler/objectivec/objectivec_extension.cc b/src/google/protobuf/compiler/objectivec/objectivec_extension.cc
index b788d0a32a..6d0e1a38ad 100644
--- a/src/google/protobuf/compiler/objectivec/objectivec_extension.cc
+++ b/src/google/protobuf/compiler/objectivec/objectivec_extension.cc
@@ -61,6 +61,11 @@ ExtensionGenerator::~ExtensionGenerator() {}
 void ExtensionGenerator::GenerateMembersHeader(io::Printer* printer) {
   std::map<string, string> vars;
   vars["method_name"] = method_name_;
+  if (IsRetainedName(method_name_)) {
+    vars["storage_attribute"] = " NS_RETURNS_NOT_RETAINED";
+  } else {
+    vars["storage_attribute"] = "";
+  }
   SourceLocation location;
   if (descriptor_->GetSourceLocation(&location)) {
     vars["comments"] = BuildCommentsString(location, true);
@@ -72,7 +77,7 @@ void ExtensionGenerator::GenerateMembersHeader(io::Printer* printer) {
   vars["deprecated_attribute"] = GetOptionalDeprecatedAttribute(descriptor_, descriptor_->file());
   printer->Print(vars,
                  "$comments$"
-                 "+ (GPBExtensionDescriptor *)$method_name$$deprecated_attribute$;\n");
+                 "+ (GPBExtensionDescriptor *)$method_name$$storage_attribute$$deprecated_attribute$;\n");
 }
 
 void ExtensionGenerator::GenerateStaticVariablesInitialization(