Adding most recent work

4 years ago · eef241890a
parent 73e0e7af12
commit eef241890a
17 changed files with 1032 additions and 240 deletions
--- a/java/core/generate-test-sources-build.xml
+++ b/java/core/generate-test-sources-build.xml
@ -26,6 +26,7 @@
        <arg value="${test.proto.dir}/com/google/protobuf/deprecated_file.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/evil_names_proto2.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/evil_names_proto3.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/example_extensible_message.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/field_presence_test.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/lazy_fields_lite.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/lite_equals_and_hash.proto"/>
@ -35,6 +36,7 @@
        <arg value="${test.proto.dir}/com/google/protobuf/map_lite_test.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/map_test.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/message_lite_extension_util_test.proto"/>
+        <arg value="${test.proto.dir}/com/google/protobuf/multiple_files_proto3.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/multiple_files_test.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/nested_builders_test.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/nested_extension.proto"/>
@ -48,7 +50,6 @@
        <arg value="${test.proto.dir}/com/google/protobuf/proto2_unknown_enum_values.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/proto3_message.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/proto3_message_lite.proto"/>
-        <arg value="${test.proto.dir}/com/google/protobuf/test.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/test_bad_identifiers.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/test_check_utf8.proto"/>
        <arg value="${test.proto.dir}/com/google/protobuf/test_check_utf8_size.proto"/>
@ -70,7 +71,10 @@
      <arg value="--experimental_allow_proto3_optional"/>
      <arg value="${protobuf.source.dir}/google/protobuf/map_proto2_unittest.proto"/>
      <arg value="${protobuf.source.dir}/google/protobuf/unittest.proto"/>
+      <arg value="${protobuf.source.dir}/google/protobuf/unittest_proto3.proto"/>
      <arg value="${test.proto.dir}/com/google/protobuf/evil_names_proto2.proto"/>
+      <arg value="${test.proto.dir}/com/google/protobuf/evil_names_proto3.proto"/>
+      <arg value="${test.proto.dir}/com/google/protobuf/multiple_files_proto3.proto"/>
    </exec>

 </project>
--- a/java/core/output.txt
+++ b/java/core/output.txt
@ -52,6 +52,10 @@ main:
 [[1;34mINFO[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/main/java/com/google/protobuf/AbstractMessageLite.java: Some input files use unchecked or unsafe operations.
 [[1;34mINFO[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/main/java/com/google/protobuf/AbstractMessageLite.java: Recompile with -Xlint:unchecked for details.
 [[1;34mINFO[m] 
+[[1;34mINFO[m] [1m--- [0;32mkotlin-maven-plugin:1.4.31:compile[m [1m(compile)[m @ [36mprotobuf-java[0;1m ---[m
+[[1;33mWARNING[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/main/kotlin/com/google/protobuf/OnlyForUseByGeneratedProtoCode.kt: (8, 2) This class can only be used with the compiler argument '-Xopt-in=kotlin.RequiresOptIn'
+[[1;33mWARNING[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/main/kotlin/com/google/protobuf/OnlyForUseByGeneratedProtoCode.kt: (14, 11) This class can only be used with the compiler argument '-Xopt-in=kotlin.RequiresOptIn'
+[[1;34mINFO[m] 
 [[1;34mINFO[m] [1m--- [0;32mmaven-antrun-plugin:1.8:run[m [1m(generate-test-sources)[m @ [36mprotobuf-java[0;1m ---[m
 [[1;34mINFO[m] Executing tasks

@ -99,168 +103,66 @@ main:
 [[1;34mINFO[m] 
 [[1;34mINFO[m] [1m--- [0;32mmaven-compiler-plugin:3.6.1:testCompile[m [1m(default-testCompile)[m @ [36mprotobuf-java[0;1m ---[m
 [[1;34mINFO[m] Changes detected - recompiling the module!
-[[1;34mINFO[m] Compiling 176 source files to /usr/local/google/home/deannagarcia/protobuf/java/core/target/test-classes
+[[1;34mINFO[m] Compiling 182 source files to /usr/local/google/home/deannagarcia/protobuf/java/core/target/test-classes
 [[1;34mINFO[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/java/com/google/protobuf/TestUtil.java: Some input files use or override a deprecated API.
 [[1;34mINFO[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/java/com/google/protobuf/TestUtil.java: Recompile with -Xlint:deprecation for details.
 [[1;34mINFO[m] 
 [[1;34mINFO[m] [1m--- [0;32mkotlin-maven-plugin:1.4.31:test-compile[m [1m(test-compile)[m @ [36mprotobuf-java[0;1m ---[m
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (452, 52) Assignment operators ambiguity: 
-public operator fun <T> Collection<Int!>.plus(element: Int!): List<Int!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Int!, UnittestProto.TestAllExtensions>.plusAssign(value: Int!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (453, 52) Assignment operators ambiguity: 
-public operator fun <T> Collection<Long!>.plus(element: Long!): List<Long!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Long!, UnittestProto.TestAllExtensions>.plusAssign(value: Long!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (454, 53) Assignment operators ambiguity: 
-public operator fun <T> Collection<Int!>.plus(element: Int!): List<Int!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Int!, UnittestProto.TestAllExtensions>.plusAssign(value: Int!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (455, 53) Assignment operators ambiguity: 
-public operator fun <T> Collection<Long!>.plus(element: Long!): List<Long!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Long!, UnittestProto.TestAllExtensions>.plusAssign(value: Long!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (456, 53) Assignment operators ambiguity: 
-public operator fun <T> Collection<Int!>.plus(element: Int!): List<Int!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Int!, UnittestProto.TestAllExtensions>.plusAssign(value: Int!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (457, 53) Assignment operators ambiguity: 
-public operator fun <T> Collection<Long!>.plus(element: Long!): List<Long!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Long!, UnittestProto.TestAllExtensions>.plusAssign(value: Long!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (458, 54) Assignment operators ambiguity: 
-public operator fun <T> Collection<Int!>.plus(element: Int!): List<Int!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Int!, UnittestProto.TestAllExtensions>.plusAssign(value: Int!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (459, 54) Assignment operators ambiguity: 
-public operator fun <T> Collection<Long!>.plus(element: Long!): List<Long!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Long!, UnittestProto.TestAllExtensions>.plusAssign(value: Long!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (460, 55) Assignment operators ambiguity: 
-public operator fun <T> Collection<Int!>.plus(element: Int!): List<Int!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Int!, UnittestProto.TestAllExtensions>.plusAssign(value: Int!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (461, 55) Assignment operators ambiguity: 
-public operator fun <T> Collection<Long!>.plus(element: Long!): List<Long!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Long!, UnittestProto.TestAllExtensions>.plusAssign(value: Long!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (462, 52) Assignment operators ambiguity: 
-public operator fun <T> Collection<Float!>.plus(element: Float!): List<Float!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Float!, UnittestProto.TestAllExtensions>.plusAssign(value: Float!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (463, 53) Assignment operators ambiguity: 
-public operator fun <T> Collection<Double!>.plus(element: Double!): List<Double!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Double!, UnittestProto.TestAllExtensions>.plusAssign(value: Double!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (464, 51) Assignment operators ambiguity: 
-public operator fun <T> Collection<Boolean!>.plus(element: Boolean!): List<Boolean!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<Boolean!, UnittestProto.TestAllExtensions>.plusAssign(value: Boolean!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (465, 53) Assignment operators ambiguity: 
-public operator fun <T> Collection<String!>.plus(element: String!): List<String!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<String!, UnittestProto.TestAllExtensions>.plusAssign(value: String!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (466, 52) Assignment operators ambiguity: 
-public operator fun <T> Collection<Serializable!>.plus(elements: Iterable<Serializable!>): List<Serializable!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<ByteString!, UnittestProto.TestAllExtensions>.plusAssign(value: ByteString!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (467, 52) Assignment operators ambiguity: 
-public operator fun <T> Collection<UnittestProto.RepeatedGroup_extension!>.plus(element: UnittestProto.RepeatedGroup_extension!): List<UnittestProto.RepeatedGroup_extension!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<UnittestProto.RepeatedGroup_extension!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.RepeatedGroup_extension!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (468, 60) Assignment operators ambiguity: 
-public operator fun <T> Collection<UnittestProto.TestAllTypes.NestedMessage!>.plus(element: UnittestProto.TestAllTypes.NestedMessage!): List<UnittestProto.TestAllTypes.NestedMessage!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<UnittestProto.TestAllTypes.NestedMessage!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.TestAllTypes.NestedMessage!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (470, 61) Assignment operators ambiguity: 
-public operator fun <T> Collection<UnittestProto.ForeignMessage!>.plus(element: UnittestProto.ForeignMessage!): List<UnittestProto.ForeignMessage!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<UnittestProto.ForeignMessage!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.ForeignMessage!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (471, 60) Assignment operators ambiguity: 
-public operator fun <T> Collection<UnittestImport.ImportMessage!>.plus(element: UnittestImport.ImportMessage!): List<UnittestImport.ImportMessage!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<UnittestImport.ImportMessage!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestImport.ImportMessage!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (473, 58) Assignment operators ambiguity: 
-public operator fun <T> Collection<UnittestProto.TestAllTypes.NestedMessage!>.plus(element: UnittestProto.TestAllTypes.NestedMessage!): List<UnittestProto.TestAllTypes.NestedMessage!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<UnittestProto.TestAllTypes.NestedMessage!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.TestAllTypes.NestedMessage!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (475, 57) Assignment operators ambiguity: 
-public operator fun <T> Collection<UnittestProto.TestAllTypes.NestedEnum!>.plus(element: UnittestProto.TestAllTypes.NestedEnum!): List<UnittestProto.TestAllTypes.NestedEnum!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<UnittestProto.TestAllTypes.NestedEnum!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.TestAllTypes.NestedEnum!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (476, 58) Assignment operators ambiguity: 
-public operator fun <T> Collection<UnittestProto.ForeignEnum!>.plus(element: UnittestProto.ForeignEnum!): List<UnittestProto.ForeignEnum!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<UnittestProto.ForeignEnum!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.ForeignEnum!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (477, 57) Assignment operators ambiguity: 
-public operator fun <T> Collection<UnittestImport.ImportEnum!>.plus(element: UnittestImport.ImportEnum!): List<UnittestImport.ImportEnum!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<UnittestImport.ImportEnum!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestImport.ImportEnum!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (478, 58) Assignment operators ambiguity: 
-public operator fun <T> Collection<String!>.plus(element: String!): List<String!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<String!, UnittestProto.TestAllExtensions>.plusAssign(value: String!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt: (479, 51) Assignment operators ambiguity: 
-public operator fun <T> Collection<String!>.plus(element: String!): List<String!> defined in kotlin.collections
-public final inline operator fun <E> ExtensionList<String!, UnittestProto.TestAllExtensions>.plusAssign(value: String!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt: (15, 5) Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, B : com.google.protobuf.GeneratedMessage.ExtendableBuilder<TypeVariable(M), TypeVariable(B)>, T> TypeVariable(B).set(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>, value: TypeVariable(T)): Unit defined in com.google.protobuf.kotlin
+public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), TypeVariable(B)>, B : com.google.protobuf.GeneratedMessageLite.ExtendableBuilder<TypeVariable(M), TypeVariable(B)>, T> TypeVariable(B).set(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>, value: TypeVariable(T)): Unit defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt: (15, 12) No set method providing array access
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt: (23, 16) Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MOrBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>, T> TypeVariable(MOrBT).get(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>): TypeVariable(T) defined in com.google.protobuf.kotlin
+public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>, T> TypeVariable(MorBT).get(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>): TypeVariable(T) defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt: (23, 23) No get method providing array access
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt: (31, 16) Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MOrBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>, T> TypeVariable(MOrBT).get(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>): TypeVariable(T) defined in com.google.protobuf.kotlin
+public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>, T> TypeVariable(MorBT).get(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>): TypeVariable(T) defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt: (31, 23) No get method providing array access
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt: (39, 41) Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MorBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt: (46, 41) Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MorBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt: (52, 41) Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MorBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt: (58, 41) Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MorBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
 [[1;34mINFO[m] [1m------------------------------------------------------------------------[m
 [[1;34mINFO[m] [1;31mBUILD FAILURE[m
 [[1;34mINFO[m] [1m------------------------------------------------------------------------[m
-[[1;34mINFO[m] Total time:  01:20 min
-[[1;34mINFO[m] Finished at: 2021-03-11T22:25:24Z
+[[1;34mINFO[m] Total time:  01:24 min
+[[1;34mINFO[m] Finished at: 2021-03-18T23:34:30Z
 [[1;34mINFO[m] [1m------------------------------------------------------------------------[m
 [[1;31mERROR[m] Failed to execute goal [32morg.jetbrains.kotlin:kotlin-maven-plugin:1.4.31:test-compile[m [1m(test-compile)[m on project [36mprotobuf-java[m: [1;31mCompilation failure[m: Compilation failure: 
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[452,52] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Int!>.plus(element: Int!): List<Int!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Int!, UnittestProto.TestAllExtensions>.plusAssign(value: Int!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[453,52] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Long!>.plus(element: Long!): List<Long!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Long!, UnittestProto.TestAllExtensions>.plusAssign(value: Long!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[454,53] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Int!>.plus(element: Int!): List<Int!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Int!, UnittestProto.TestAllExtensions>.plusAssign(value: Int!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[455,53] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Long!>.plus(element: Long!): List<Long!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Long!, UnittestProto.TestAllExtensions>.plusAssign(value: Long!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[456,53] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Int!>.plus(element: Int!): List<Int!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Int!, UnittestProto.TestAllExtensions>.plusAssign(value: Int!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[457,53] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Long!>.plus(element: Long!): List<Long!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Long!, UnittestProto.TestAllExtensions>.plusAssign(value: Long!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[458,54] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Int!>.plus(element: Int!): List<Int!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Int!, UnittestProto.TestAllExtensions>.plusAssign(value: Int!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[459,54] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Long!>.plus(element: Long!): List<Long!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Long!, UnittestProto.TestAllExtensions>.plusAssign(value: Long!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[460,55] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Int!>.plus(element: Int!): List<Int!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Int!, UnittestProto.TestAllExtensions>.plusAssign(value: Int!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[461,55] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Long!>.plus(element: Long!): List<Long!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Long!, UnittestProto.TestAllExtensions>.plusAssign(value: Long!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[462,52] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Float!>.plus(element: Float!): List<Float!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Float!, UnittestProto.TestAllExtensions>.plusAssign(value: Float!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[463,53] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Double!>.plus(element: Double!): List<Double!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Double!, UnittestProto.TestAllExtensions>.plusAssign(value: Double!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[464,51] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Boolean!>.plus(element: Boolean!): List<Boolean!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<Boolean!, UnittestProto.TestAllExtensions>.plusAssign(value: Boolean!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[465,53] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<String!>.plus(element: String!): List<String!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<String!, UnittestProto.TestAllExtensions>.plusAssign(value: String!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[466,52] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<Serializable!>.plus(elements: Iterable<Serializable!>): List<Serializable!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<ByteString!, UnittestProto.TestAllExtensions>.plusAssign(value: ByteString!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[467,52] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<UnittestProto.RepeatedGroup_extension!>.plus(element: UnittestProto.RepeatedGroup_extension!): List<UnittestProto.RepeatedGroup_extension!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<UnittestProto.RepeatedGroup_extension!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.RepeatedGroup_extension!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[468,60] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<UnittestProto.TestAllTypes.NestedMessage!>.plus(element: UnittestProto.TestAllTypes.NestedMessage!): List<UnittestProto.TestAllTypes.NestedMessage!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<UnittestProto.TestAllTypes.NestedMessage!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.TestAllTypes.NestedMessage!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[470,61] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<UnittestProto.ForeignMessage!>.plus(element: UnittestProto.ForeignMessage!): List<UnittestProto.ForeignMessage!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<UnittestProto.ForeignMessage!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.ForeignMessage!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[471,60] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<UnittestImport.ImportMessage!>.plus(element: UnittestImport.ImportMessage!): List<UnittestImport.ImportMessage!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<UnittestImport.ImportMessage!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestImport.ImportMessage!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[473,58] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<UnittestProto.TestAllTypes.NestedMessage!>.plus(element: UnittestProto.TestAllTypes.NestedMessage!): List<UnittestProto.TestAllTypes.NestedMessage!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<UnittestProto.TestAllTypes.NestedMessage!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.TestAllTypes.NestedMessage!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[475,57] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<UnittestProto.TestAllTypes.NestedEnum!>.plus(element: UnittestProto.TestAllTypes.NestedEnum!): List<UnittestProto.TestAllTypes.NestedEnum!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<UnittestProto.TestAllTypes.NestedEnum!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.TestAllTypes.NestedEnum!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[476,58] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<UnittestProto.ForeignEnum!>.plus(element: UnittestProto.ForeignEnum!): List<UnittestProto.ForeignEnum!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<UnittestProto.ForeignEnum!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestProto.ForeignEnum!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[477,57] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<UnittestImport.ImportEnum!>.plus(element: UnittestImport.ImportEnum!): List<UnittestImport.ImportEnum!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<UnittestImport.ImportEnum!, UnittestProto.TestAllExtensions>.plusAssign(value: UnittestImport.ImportEnum!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[478,58] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<String!>.plus(element: String!): List<String!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<String!, UnittestProto.TestAllExtensions>.plusAssign(value: String!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
-[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt:[479,51] Assignment operators ambiguity: 
-[[1;31mERROR[m] public operator fun <T> Collection<String!>.plus(element: String!): List<String!> defined in kotlin.collections
-[[1;31mERROR[m] public final inline operator fun <E> ExtensionList<String!, UnittestProto.TestAllExtensions>.plusAssign(value: String!): Unit defined in protobuf_unittest.TestAllExtensionsKt.Dsl
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt:[15,5] Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, B : com.google.protobuf.GeneratedMessage.ExtendableBuilder<TypeVariable(M), TypeVariable(B)>, T> TypeVariable(B).set(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>, value: TypeVariable(T)): Unit defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), TypeVariable(B)>, B : com.google.protobuf.GeneratedMessageLite.ExtendableBuilder<TypeVariable(M), TypeVariable(B)>, T> TypeVariable(B).set(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>, value: TypeVariable(T)): Unit defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt:[15,12] No set method providing array access
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt:[23,16] Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MOrBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>, T> TypeVariable(MOrBT).get(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>): TypeVariable(T) defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>, T> TypeVariable(MorBT).get(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>): TypeVariable(T) defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt:[23,23] No get method providing array access
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt:[31,16] Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MOrBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>, T> TypeVariable(MOrBT).get(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>): TypeVariable(T) defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>, T> TypeVariable(MorBT).get(extension: ExtensionLite<TypeVariable(M), TypeVariable(T)>): TypeVariable(T) defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt:[31,23] No get method providing array access
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt:[39,41] Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MorBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt:[46,41] Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MorBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt:[52,41] Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MorBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] /usr/local/google/home/deannagarcia/protobuf/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt:[58,41] Unresolved reference. None of the following candidates is applicable because of receiver type mismatch: 
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessage.ExtendableMessage<TypeVariable(M)>, MorBT : com.google.protobuf.GeneratedMessage.ExtendableMessageOrBuilder<TypeVariable(M)>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
+[[1;31mERROR[m] public operator fun <M : com.google.protobuf.GeneratedMessageLite.ExtendableMessage<TypeVariable(M), *>, MorBT : com.google.protobuf.GeneratedMessageLite.ExtendableMessageOrBuilder<TypeVariable(M), *>> TypeVariable(MorBT).contains(extension: ExtensionLite<TypeVariable(M), *>): Boolean defined in com.google.protobuf.kotlin
 [[1;31mERROR[m] -> [1m[Help 1][m
 [[1;31mERROR[m] 
 [[1;31mERROR[m] To see the full stack trace of the errors, re-run Maven with the [1m-e[m switch.
--- a/java/core/pom.xml
+++ b/java/core/pom.xml
@ -41,20 +41,26 @@
      <artifactId>guava</artifactId>
      <scope>test</scope>
    </dependency>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava-testlib</artifactId>
+      <scope>test</scope>
+    </dependency>
    <dependency>
      <groupId>com.google.truth</groupId>
      <artifactId>truth</artifactId>
      <scope>test</scope>
    </dependency>
    <dependency>
-        <groupId>org.jetbrains.kotlin</groupId>
-        <artifactId>kotlin-stdlib-jdk7</artifactId>
-        <version>${kotlin.version}</version>
+      <groupId>org.jetbrains.kotlin</groupId>
+      <artifactId>kotlin-stdlib-jdk7</artifactId>
+      <version>${kotlin.version}</version>
    </dependency>
    <dependency>
-        <groupId>org.jetbrains.kotlin</groupId>
-        <artifactId>kotlin-reflect</artifactId>
-        <version>${kotlin.version}</version>
+      <groupId>org.jetbrains.kotlin</groupId>
+      <artifactId>kotlin-test</artifactId>
+      <version>${kotlin.version}</version>
+      <scope>test</scope>
    </dependency>
  </dependencies>

--- a/java/core/src/main/kotlin/com/google/protobuf/ExtendableMessageExtensionsLite.kt
+++ b/java/core/src/main/kotlin/com/google/protobuf/ExtendableMessageExtensionsLite.kt
@ -0,0 +1,28 @@
+package com.google.protobuf.kotlin
+
+import com.google.protobuf.ExtensionLite
+import com.google.protobuf.GeneratedMessageLite
+
+/** Gets the value of the proto extension. */
+operator fun <
+  M : GeneratedMessageLite.ExtendableMessage<M, *>,
+  MOrBT : GeneratedMessageLite.ExtendableMessageOrBuilder<M, *>,
+  T
+  > MOrBT.get(extension: ExtensionLite<M, T>): T = getExtension(extension)
+
+/** Sets the current value of the proto extension in this builder. */
+operator fun <
+  M : GeneratedMessageLite.ExtendableMessage<M, B>,
+  B : GeneratedMessageLite.ExtendableBuilder<M, B>,
+  T
+  > B.set(extension: ExtensionLite<M, T>, value: T) {
+  setExtension(extension, value)
+}
+
+/** Returns true if the specified extension is set. */
+operator fun <
+  M : GeneratedMessageLite.ExtendableMessage<M, *>,
+  MorBT : GeneratedMessageLite.ExtendableMessageOrBuilder<M, *>
+  > MorBT.contains(
+  extension: ExtensionLite<M, *>
+): Boolean = hasExtension(extension)
--- a/java/core/src/test/kotlin/com/google/protobuf/DslListTest.kt
+++ b/java/core/src/test/kotlin/com/google/protobuf/DslListTest.kt
@ -0,0 +1,98 @@
+package com.google.protobuf.kotlin
+
+import com.google.common.testing.EqualsTester
+import com.google.common.truth.Truth.assertThat
+import kotlin.test.assertFailsWith
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+/** Tests for [DslList]. */
+@RunWith(JUnit4::class)
+@OptIn(OnlyForUseByGeneratedProtoCode::class)
+class DslListTest {
+  class DummyProxy private constructor() : DslProxy()
+
+  @Test
+  fun matchesList() {
+    assertThat(DslList<Int, DummyProxy>(listOf(1, 2, 3))).containsExactly(1, 2, 3).inOrder()
+  }
+
+  @Test
+  fun reflectsChangesInList() {
+    val mutableList = mutableListOf(1, 2, 3)
+    val dslList = DslList<Int, DummyProxy>(mutableList)
+    mutableList.add(4)
+    assertThat(dslList).containsExactly(1, 2, 3, 4).inOrder()
+  }
+
+  @Test
+  fun dslListIsNotMutable() {
+    val dslList = DslList<Int, DummyProxy>(mutableListOf(1, 2, 3))
+    assertThat(dslList is MutableList<*>).isFalse()
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslListIsNotEvenSecretlyMutable() {
+    val dslList = DslList<Int, DummyProxy>(mutableListOf(1, 2, 3))
+    val dslListAsJavaUtil = dslList as java.util.List<Int>
+    assertFailsWith<UnsupportedOperationException> {
+      dslListAsJavaUtil.add(4)
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslList_IteratorIsNotEvenSecretlyMutable() {
+    val dslList = DslList<Int, DummyProxy>(mutableListOf(1, 2, 3))
+    val iterator = dslList.iterator() as java.util.Iterator<Int>
+    iterator.next()
+
+    assertFailsWith<UnsupportedOperationException> {
+      iterator.remove()
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslList_ListIteratorIsNotEvenSecretlyMutable() {
+    val dslList = DslList<Int, DummyProxy>(mutableListOf(1, 2, 3))
+    val iterator = dslList.listIterator() as java.util.ListIterator<Int>
+    iterator.next()
+
+    assertFailsWith<UnsupportedOperationException> {
+      iterator.remove()
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslList_ListIteratorIndexIsNotEvenSecretlyMutable() {
+    val dslList = DslList<Int, DummyProxy>(mutableListOf(1, 2, 3))
+    val iterator = dslList.listIterator(1) as java.util.ListIterator<Int>
+    iterator.next()
+
+    assertFailsWith<UnsupportedOperationException> {
+      iterator.remove()
+    }
+  }
+
+  @Test
+  fun expectedToString() {
+    assertThat(DslList<Int, DummyProxy>(listOf(1, 2)).toString()).isEqualTo("[1, 2]")
+  }
+
+  @Test
+  fun equality() {
+    EqualsTester()
+      .addEqualityGroup(DslList<Int, DummyProxy>(listOf(1, 2)), listOf(1, 2))
+      .addEqualityGroup(DslList<Int, DummyProxy>(listOf(2, 2)), listOf(2, 2))
+      .addEqualityGroup(
+        DslList<Int, DummyProxy>(emptyList()),
+        DslList<String, DummyProxy>(emptyList()),
+        emptyList<Int>()
+      )
+      .testEquals()
+  }
+}
--- a/java/core/src/test/kotlin/com/google/protobuf/DslMapTest.kt
+++ b/java/core/src/test/kotlin/com/google/protobuf/DslMapTest.kt
@ -0,0 +1,164 @@
+package com.google.protobuf.kotlin
+
+import com.google.common.testing.EqualsTester
+import com.google.common.truth.Truth.assertThat
+import kotlin.test.assertFailsWith
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+@RunWith(JUnit4::class)
+@OptIn(OnlyForUseByGeneratedProtoCode::class)
+class DslMapTest {
+  class DummyProxy private constructor() : DslProxy()
+
+  @Test
+  fun matchesMap() {
+    assertThat(DslMap<Int, Int, DummyProxy>(mapOf(1 to -1, 2 to -2)))
+      .containsExactly(1, -1, 2, -2)
+  }
+
+  @Test
+  fun reflectsChangesInMap() {
+    val mutableMap = mutableMapOf(1 to -1, 2 to -2)
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMap)
+    mutableMap[3] = -3
+    assertThat(dslMap).containsExactly(1, -1, 2, -2, 3, -3).inOrder()
+  }
+
+  @Test
+  fun dslMapIsNotMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    assertThat(dslMap is MutableMap<*, *>).isFalse()
+  }
+
+  @Test
+  fun dslMapKeysAreNotMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    assertThat(dslMap.keys is MutableSet<*>).isFalse()
+  }
+
+  @Test
+  fun dslMapValuesAreNotMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    assertThat(dslMap.values is MutableSet<*>).isFalse()
+  }
+
+  @Test
+  fun dslMapEntriesAreNotMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    assertThat(dslMap.entries is MutableSet<*>).isFalse()
+  }
+
+  @Test
+  fun dslMapEntryObjectsAreNotMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    assertThat(dslMap.entries.single() is MutableMap.MutableEntry<*, *>).isFalse()
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslMapIsNotEvenSecretlyMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    val dslMapAsJavaUtilMap = dslMap as java.util.Map<Int, Int>
+    assertFailsWith<UnsupportedOperationException> {
+      dslMapAsJavaUtilMap.put(2, -2)
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslMapKeysAreNotEvenSecretlyMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    val dslMapKeysAsJavaUtilSet = dslMap.keys as java.util.Set<Int>
+    assertFailsWith<UnsupportedOperationException> {
+      dslMapKeysAsJavaUtilSet.remove(1)
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslMapKeysIteratorIsNotEvenSecretlyMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    val dslMapKeysAsJavaUtilSet = dslMap.keys as java.util.Set<Int>
+    val itr = dslMapKeysAsJavaUtilSet.iterator()
+    itr.next()
+    assertFailsWith<UnsupportedOperationException> {
+      itr.remove()
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslMapValuesAreNotEvenSecretlyMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    val dslMapValuesAsJavaUtilCollection = dslMap.values as java.util.Collection<Int>
+    assertFailsWith<UnsupportedOperationException> {
+      dslMapValuesAsJavaUtilCollection.remove(1)
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslMapValuesIteratorIsNotEvenSecretlyMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    val dslMapValuesAsJavaUtilCollection = dslMap.values as java.util.Collection<Int>
+    val itr = dslMapValuesAsJavaUtilCollection.iterator()
+    itr.next()
+    assertFailsWith<UnsupportedOperationException> {
+      itr.remove()
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslMapEntriesAreNotEvenSecretlyMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    val dslMapEntriesAsJavaUtilSet = dslMap.entries as java.util.Set<Map.Entry<Int, Int>>
+    val entry = dslMap.entries.single()
+    assertFailsWith<UnsupportedOperationException> {
+      dslMapEntriesAsJavaUtilSet.remove(entry)
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslMapEntriesIteratorIsNotEvenSecretlyMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    val dslMapEntriesAsJavaUtilSet = dslMap.entries as java.util.Set<Map.Entry<Int, Int>>
+    val itr = dslMapEntriesAsJavaUtilSet.iterator()
+    itr.next()
+    assertFailsWith<UnsupportedOperationException> {
+      itr.remove()
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun dslMapEntryObjectsAreNotEvenSecretlyMutable() {
+    val dslMap = DslMap<Int, Int, DummyProxy>(mutableMapOf(1 to -1))
+    val dslMapEntryAsJavaUtilMapEntry = dslMap.entries.single() as java.util.Map.Entry<Int, Int>
+    assertFailsWith<UnsupportedOperationException> {
+      dslMapEntryAsJavaUtilMapEntry.value = 2
+    }
+  }
+
+  @Test
+  fun expectedToString() {
+    assertThat(DslMap<Int, Int, DummyProxy>(mapOf(1 to 2, 2 to 3)).toString())
+      .isEqualTo("{1=2, 2=3}")
+  }
+
+  @Test
+  fun equality() {
+    EqualsTester()
+      .addEqualityGroup(DslMap<Int, Int, DummyProxy>(mapOf(1 to 2, 2 to 3)), mapOf(1 to 2, 2 to 3))
+      .addEqualityGroup(DslMap<Int, Int, DummyProxy>(mapOf(1 to 3, 2 to 3)), mapOf(1 to 3, 2 to 3))
+      .addEqualityGroup(
+        DslMap<Int, Int, DummyProxy>(emptyMap()),
+        DslMap<String, String, DummyProxy>(emptyMap()),
+        emptyMap<Int, Int>()
+      )
+      .testEquals()
+  }
+}
--- a/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt
+++ b/java/core/src/test/kotlin/com/google/protobuf/ExtendableMessageExtensionsTest.kt
@ -0,0 +1,60 @@
+package com.google.protobuf.kotlin
+
+import com.google.common.truth.Truth.assertThat
+import example_extensible_message.ExampleExtensibleMessage
+import example_extensible_message.ExampleExtensibleMessageOuterClass as TestProto
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+@RunWith(JUnit4::class)
+class ExtendableMessageExtensionsTest {
+  @Test
+  fun setOnBuilder() {
+    val builder = ExampleExtensibleMessage.newBuilder()
+    builder[TestProto.int32Extension] = 5
+    assertThat(builder.build().getExtension(TestProto.int32Extension)).isEqualTo(5)
+  }
+
+  @Test
+  fun getOnBuilder() {
+    val builder = ExampleExtensibleMessage.newBuilder()
+      .setExtension(TestProto.int32Extension, 6)
+    assertThat(builder[TestProto.int32Extension]).isEqualTo(6)
+  }
+
+  @Test
+  fun getOnMessage() {
+    val message = ExampleExtensibleMessage.newBuilder()
+      .setExtension(TestProto.int32Extension, 6)
+      .build()
+    assertThat(message[TestProto.int32Extension]).isEqualTo(6)
+  }
+
+  @Test
+  fun containsPositiveOnMessage() {
+    val message = ExampleExtensibleMessage.newBuilder()
+      .setExtension(TestProto.int32Extension, 6)
+      .build()
+    assertThat(TestProto.int32Extension in message).isTrue()
+  }
+
+  @Test
+  fun containsPositiveOnBuilder() {
+    val builder = ExampleExtensibleMessage.newBuilder()
+      .setExtension(TestProto.int32Extension, 6)
+    assertThat(TestProto.int32Extension in builder).isTrue()
+  }
+
+  @Test
+  fun containsNegativeOnMessage() {
+    val message = ExampleExtensibleMessage.newBuilder().build()
+    assertThat(TestProto.int32Extension in message).isFalse()
+  }
+
+  @Test
+  fun containsNegativeOnBuilder() {
+    val builder = ExampleExtensibleMessage.newBuilder()
+    assertThat(TestProto.int32Extension in builder).isFalse()
+  }
+}
--- a/java/core/src/test/kotlin/com/google/protobuf/ExtensionListTest.kt
+++ b/java/core/src/test/kotlin/com/google/protobuf/ExtensionListTest.kt
@ -0,0 +1,125 @@
+package com.google.protobuf.kotlin
+
+import com.google.common.testing.EqualsTester
+import com.google.common.truth.Truth.assertThat
+import example_extensible_message.ExampleExtensibleMessage
+import example_extensible_message.ExampleExtensibleMessageOuterClass as TestProto
+import kotlin.test.assertFailsWith
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+/** Tests for [DslList]. */
+@RunWith(JUnit4::class)
+@OptIn(OnlyForUseByGeneratedProtoCode::class)
+class ExtensionListTest {
+  class DummyProxy private constructor() : DslProxy()
+
+  @Test
+  fun matchesList() {
+    assertThat(
+      ExtensionList<Int, ExampleExtensibleMessage>(
+        TestProto.repeatedExtension, listOf(1, 2, 3)
+      )
+    ).containsExactly(1, 2, 3).inOrder()
+  }
+
+  @Test
+  fun reflectsChangesInList() {
+    val mutableList = mutableListOf(1, 2, 3)
+    val extensionList = ExtensionList<Int, ExampleExtensibleMessage>(
+      TestProto.repeatedExtension, mutableList
+    )
+    mutableList.add(4)
+    assertThat(extensionList).containsExactly(1, 2, 3, 4).inOrder()
+  }
+
+  @Test
+  fun extensionListIsNotMutable() {
+    val extensionList = ExtensionList<Int, ExampleExtensibleMessage>(
+      TestProto.repeatedExtension, mutableListOf(1, 2, 3)
+    )
+    assertThat(extensionList is MutableList<*>).isFalse()
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun extensionListIsNotEvenSecretlyMutable() {
+    val extensionList = ExtensionList<Int, ExampleExtensibleMessage>(
+      TestProto.repeatedExtension, mutableListOf(1, 2, 3)
+    )
+    val extensionListAsJavaUtil = extensionList as java.util.List<Int>
+    assertFailsWith<UnsupportedOperationException> {
+      extensionListAsJavaUtil.add(4)
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun extensionList_IteratorIsNotEvenSecretlyMutable() {
+    val extensionList = ExtensionList<Int, ExampleExtensibleMessage>(
+      TestProto.repeatedExtension, mutableListOf(1, 2, 3)
+    )
+    val iterator = extensionList.iterator() as java.util.Iterator<Int>
+    iterator.next()
+
+    assertFailsWith<UnsupportedOperationException> {
+      iterator.remove()
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun extensionList_ListIteratorIsNotEvenSecretlyMutable() {
+    val extensionList = ExtensionList<Int, ExampleExtensibleMessage>(
+      TestProto.repeatedExtension, mutableListOf(1, 2, 3)
+    )
+    val iterator = extensionList.listIterator() as java.util.ListIterator<Int>
+    iterator.next()
+
+    assertFailsWith<UnsupportedOperationException> {
+      iterator.remove()
+    }
+  }
+
+  @Suppress("PLATFORM_CLASS_MAPPED_TO_KOTLIN", "UNCHECKED_CAST")
+  @Test
+  fun extensionList_ListIteratorIndexIsNotEvenSecretlyMutable() {
+    val extensionList = ExtensionList<Int, ExampleExtensibleMessage>(
+      TestProto.repeatedExtension, mutableListOf(1, 2, 3)
+    )
+    val iterator = extensionList.listIterator(1) as java.util.ListIterator<Int>
+    iterator.next()
+
+    assertFailsWith<UnsupportedOperationException> {
+      iterator.remove()
+    }
+  }
+
+  @Test
+  fun expectedToString() {
+    assertThat(
+      ExtensionList<Int, ExampleExtensibleMessage>(TestProto.repeatedExtension, listOf(1, 2))
+        .toString()
+    ).isEqualTo("[1, 2]")
+  }
+
+  @Test
+  fun equality() {
+    EqualsTester()
+      .addEqualityGroup(
+        ExtensionList<Int, ExampleExtensibleMessage>(TestProto.repeatedExtension, listOf(1, 2)),
+        ExtensionList<Int, ExampleExtensibleMessage>(TestProto.differentExtension, listOf(1, 2)),
+        listOf(1, 2)
+      )
+      .addEqualityGroup(
+        ExtensionList<Int, ExampleExtensibleMessage>(TestProto.repeatedExtension, listOf(2, 2)),
+        listOf(2, 2)
+      )
+      .addEqualityGroup(
+        ExtensionList<Int, ExampleExtensibleMessage>(TestProto.repeatedExtension, emptyList()),
+        emptyList<Int>()
+      )
+      .testEquals()
+  }
+}
--- a/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt
+++ b/java/core/src/test/kotlin/com/google/protobuf/Proto2Test.kt
@ -44,7 +44,6 @@ import org.junit.runners.JUnit4
 class Proto2Test {
  @Test
  fun testSetters() {
-    val myInt: Int = 301
    assertThat(
      testAllTypes {
        optionalInt32 = 101
@ -103,7 +102,7 @@ class Proto2Test {
        repeatedImportEnum.add(ImportEnum.IMPORT_BAR)
        repeatedStringPiece.add("224")
        repeatedCord.add("225")
-        repeatedInt32 += myInt
+        repeatedInt32 += 301
        repeatedInt64 += 302
        repeatedUint32 += 303
        repeatedUint64 += 304
@ -449,34 +448,34 @@ class Proto2Test {
        this[UnittestProto.repeatedImportEnumExtension].add(ImportEnum.IMPORT_BAR)
        this[UnittestProto.repeatedStringPieceExtension].add("224")
        this[UnittestProto.repeatedCordExtension].add("225")
-        this[UnittestProto.repeatedInt32Extension] += 301
-        this[UnittestProto.repeatedInt64Extension] += 302L
-        this[UnittestProto.repeatedUint32Extension] += 303
-        this[UnittestProto.repeatedUint64Extension] += 304L
-        this[UnittestProto.repeatedSint32Extension] += 305
-        this[UnittestProto.repeatedSint64Extension] += 306L
-        this[UnittestProto.repeatedFixed32Extension] += 307
-        this[UnittestProto.repeatedFixed64Extension] += 308L
-        this[UnittestProto.repeatedSfixed32Extension] += 309
-        this[UnittestProto.repeatedSfixed64Extension] += 310L
-        this[UnittestProto.repeatedFloatExtension] += 311F
-        this[UnittestProto.repeatedDoubleExtension] += 312.0
-        this[UnittestProto.repeatedBoolExtension] += false
-        this[UnittestProto.repeatedStringExtension] += "315"
-        this[UnittestProto.repeatedBytesExtension] += toBytes("316")
-        this[UnittestProto.repeatedGroupExtension] += repeatedGroupExtension { a = 317 }
-        this[UnittestProto.repeatedNestedMessageExtension] +=
-          TestAllTypesKt.nestedMessage { bb = 318 }
-        this[UnittestProto.repeatedForeignMessageExtension] += foreignMessage { c = 319 }
-        this[UnittestProto.repeatedImportMessageExtension] +=
-          ImportMessage.newBuilder().setD(320).build()
-        this[UnittestProto.repeatedLazyMessageExtension] +=
-          TestAllTypesKt.nestedMessage { bb = 327 }
-        this[UnittestProto.repeatedNestedEnumExtension] += NestedEnum.BAZ
-        this[UnittestProto.repeatedForeignEnumExtension] += ForeignEnum.FOREIGN_BAZ
-        this[UnittestProto.repeatedImportEnumExtension] += ImportEnum.IMPORT_BAZ
-        this[UnittestProto.repeatedStringPieceExtension] += "324"
-        this[UnittestProto.repeatedCordExtension] += "325"
+        this[UnittestProto.repeatedInt32Extension].add(301)
+        this[UnittestProto.repeatedInt64Extension].add(302L)
+        this[UnittestProto.repeatedUint32Extension].add(303)
+        this[UnittestProto.repeatedUint64Extension].add(304L)
+        this[UnittestProto.repeatedSint32Extension].add(305)
+        this[UnittestProto.repeatedSint64Extension].add(306L)
+        this[UnittestProto.repeatedFixed32Extension].add(307)
+        this[UnittestProto.repeatedFixed64Extension].add(308L)
+        this[UnittestProto.repeatedSfixed32Extension].add(309)
+        this[UnittestProto.repeatedSfixed64Extension].add(310L)
+        this[UnittestProto.repeatedFloatExtension].add(311F)
+        this[UnittestProto.repeatedDoubleExtension].add(312.0)
+        this[UnittestProto.repeatedBoolExtension].add(false)
+        this[UnittestProto.repeatedStringExtension].add("315")
+        this[UnittestProto.repeatedBytesExtension].add(toBytes("316"))
+        this[UnittestProto.repeatedGroupExtension].add(repeatedGroupExtension { a = 317 })
+        this[UnittestProto.repeatedNestedMessageExtension]
+          .add(TestAllTypesKt.nestedMessage { bb = 318 })
+        this[UnittestProto.repeatedForeignMessageExtension].add(foreignMessage { c = 319 })
+        this[UnittestProto.repeatedImportMessageExtension]
+          .add(ImportMessage.newBuilder().setD(320).build())
+        this[UnittestProto.repeatedLazyMessageExtension]
+          .add(TestAllTypesKt.nestedMessage { bb = 327 })
+        this[UnittestProto.repeatedNestedEnumExtension].add(NestedEnum.BAZ)
+        this[UnittestProto.repeatedForeignEnumExtension].add(ForeignEnum.FOREIGN_BAZ)
+        this[UnittestProto.repeatedImportEnumExtension].add(ImportEnum.IMPORT_BAZ)
+        this[UnittestProto.repeatedStringPieceExtension].add("324")
+        this[UnittestProto.repeatedCordExtension].add("325")
        this[UnittestProto.defaultInt32Extension] = 401
        this[UnittestProto.defaultInt64Extension] = 402L
        this[UnittestProto.defaultUint32Extension] = 403
--- a/java/core/src/test/kotlin/com/google/protobuf/Proto3Test.kt
+++ b/java/core/src/test/kotlin/com/google/protobuf/Proto3Test.kt
@ -0,0 +1,340 @@
+package com.google.protobuf.kotlin
+
+import com.google.common.truth.Truth.assertThat
+import evil_names_proto3.EvilNamesProto3OuterClass.EvilNamesProto3
+import evil_names_proto3.EvilNamesProto3OuterClass.HardKeywordsAllTypes
+import evil_names_proto3.EvilNamesProto3OuterClass.Class
+import evil_names_proto3.HardKeywordsAllTypesKt
+import evil_names_proto3.class_
+import evil_names_proto3.evilNamesProto3
+import evil_names_proto3.hardKeywordsAllTypes
+import multiple_files_proto3.MultipleFilesMessageA
+import multiple_files_proto3.MultipleFilesMessageB
+import multiple_files_proto3.multipleFilesMessageA
+import multiple_files_proto3.multipleFilesMessageB
+import proto3_unittest.UnittestProto3
+import proto3_unittest.TestAllTypesKt
+import proto3_unittest.TestAllTypesKt.nestedMessage
+import proto3_unittest.UnittestProto3.TestAllTypes
+import proto3_unittest.UnittestProto3.TestAllTypes.NestedEnum
+import proto3_unittest.UnittestProto3.TestEmptyMessage
+import proto3_unittest.copy
+import proto3_unittest.testAllTypes
+import proto3_unittest.testEmptyMessage
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.JUnit4
+
+@RunWith(JUnit4::class)
+class Proto3Test {
+  @Test
+  fun testGettersAndSetters() {
+    testAllTypes {
+      optionalInt32 = 101
+      assertThat(optionalInt32).isEqualTo(101)
+      optionalString = "115"
+      assertThat(optionalString).isEqualTo("115")
+      optionalNestedMessage = TestAllTypesKt.nestedMessage { bb = 118 }
+      assertThat(optionalNestedMessage).isEqualTo(TestAllTypesKt.nestedMessage { bb = 118 })
+      optionalNestedEnum = NestedEnum.BAZ
+      assertThat(optionalNestedEnum).isEqualTo(NestedEnum.BAZ)
+      oneofUint32 = 601
+      assertThat(oneofUint32).isEqualTo(601)
+    }
+  }
+
+  @Test
+  fun testRepeatedGettersAndSetters() {
+    testAllTypes {
+      repeatedInt32.addAll(listOf(1, 2))
+      assertThat(repeatedInt32).isEqualTo(listOf(1, 2))
+      repeatedInt32 += listOf(3, 4)
+      assertThat(repeatedInt32).isEqualTo(listOf(1, 2, 3, 4))
+      repeatedInt32[0] = 5
+      assertThat(repeatedInt32).isEqualTo(listOf(5, 2, 3, 4))
+
+      repeatedString.addAll(listOf("1", "2"))
+      assertThat(repeatedString).isEqualTo(listOf("1", "2"))
+      repeatedString += listOf("3", "4")
+      assertThat(repeatedString).isEqualTo(listOf("1", "2", "3", "4"))
+      repeatedString[0] = "5"
+      assertThat(repeatedString).isEqualTo(listOf("5", "2", "3", "4"))
+
+      repeatedNestedMessage.addAll(listOf(nestedMessage { bb = 1 }, nestedMessage { bb = 2 }))
+      assertThat(repeatedNestedMessage).isEqualTo(
+        listOf(
+          nestedMessage { bb = 1 },
+          nestedMessage { bb = 2 }
+        )
+      )
+      repeatedNestedMessage += listOf(nestedMessage { bb = 3 }, nestedMessage { bb = 4 })
+      assertThat(repeatedNestedMessage).isEqualTo(
+        listOf(
+          nestedMessage { bb = 1 },
+          nestedMessage { bb = 2 },
+          nestedMessage { bb = 3 },
+          nestedMessage { bb = 4 }
+        )
+      )
+      repeatedNestedMessage[0] = nestedMessage { bb = 5 }
+      assertThat(repeatedNestedMessage).isEqualTo(
+        listOf(
+          nestedMessage { bb = 5 },
+          nestedMessage { bb = 2 },
+          nestedMessage { bb = 3 },
+          nestedMessage { bb = 4 }
+        )
+      )
+
+      repeatedNestedEnum.addAll(listOf(NestedEnum.FOO, NestedEnum.BAR))
+      assertThat(repeatedNestedEnum).isEqualTo(listOf(NestedEnum.FOO, NestedEnum.BAR))
+      repeatedNestedEnum += listOf(NestedEnum.BAZ, NestedEnum.FOO)
+      assertThat(repeatedNestedEnum).isEqualTo(
+        listOf(NestedEnum.FOO, NestedEnum.BAR, NestedEnum.BAZ, NestedEnum.FOO)
+      )
+      repeatedNestedEnum[0] = NestedEnum.BAR
+      assertThat(repeatedNestedEnum).isEqualTo(
+        listOf(NestedEnum.BAR, NestedEnum.BAR, NestedEnum.BAZ, NestedEnum.FOO)
+      )
+    }
+  }
+
+  @Test
+  fun testClears() {
+    assertThat(
+      testAllTypes {
+        optionalInt32 = 101
+        clearOptionalInt32()
+
+        optionalString = "115"
+        clearOptionalString()
+
+        optionalNestedMessage = TestAllTypesKt.nestedMessage { bb = 118 }
+        clearOptionalNestedMessage()
+
+        optionalNestedEnum = NestedEnum.BAZ
+        clearOptionalNestedEnum()
+
+        oneofUint32 = 601
+        clearOneofUint32()
+      }
+    ).isEqualTo(
+      TestAllTypes.newBuilder().build()
+    )
+  }
+
+  @Test
+  fun testCopy() {
+    val message = testAllTypes {
+      optionalInt32 = 101
+      optionalString = "115"
+    }
+    val modifiedMessage = message.copy {
+      optionalInt32 = 201
+    }
+
+    assertThat(message).isEqualTo(
+      TestAllTypes.newBuilder()
+        .setOptionalInt32(101)
+        .setOptionalString("115")
+        .build()
+    )
+    assertThat(modifiedMessage).isEqualTo(
+      TestAllTypes.newBuilder()
+        .setOptionalInt32(201)
+        .setOptionalString("115")
+        .build()
+    )
+  }
+
+  @Test
+  fun testOneof() {
+    val message = testAllTypes {
+      oneofString = "foo"
+      assertThat(oneofFieldCase)
+        .isEqualTo(TestAllTypes.OneofFieldCase.ONEOF_STRING)
+      assertThat(oneofString).isEqualTo("foo")
+      clearOneofField()
+      assertThat(oneofFieldCase)
+        .isEqualTo(TestAllTypes.OneofFieldCase.ONEOFFIELD_NOT_SET)
+      oneofUint32 = 5
+    }
+
+    assertThat(message.getOneofFieldCase())
+      .isEqualTo(TestAllTypes.OneofFieldCase.ONEOF_UINT32)
+    assertThat(message.getOneofUint32()).isEqualTo(5)
+  }
+
+  @Test
+  fun testEmptyMessages() {
+    assertThat(
+      testEmptyMessage {}
+    ).isEqualTo(
+      TestEmptyMessage.newBuilder().build()
+    )
+  }
+
+  @Test
+  fun testEvilNames() {
+    assertThat(
+      evilNamesProto3 {
+        initialized = true
+        hasFoo = true
+        bar = "foo"
+        isInitialized = true
+        fooBar = "foo"
+        aLLCAPS += "foo"
+        aLLCAPSMAP[1] = true
+        hasUnderbarPrecedingNumeric1Foo = true
+        hasUnderbarPrecedingNumeric42Bar = true
+        hasUnderbarPrecedingNumeric123Foo42BarBaz = true
+        extension += "foo"
+        class_ = "foo"
+        int = 1.0
+        long = true
+        boolean = 1L
+        sealed = "foo"
+        interface_ = 1F
+        in_ = 1
+        object_ = "foo"
+        cachedSize_ = "foo"
+        serializedSize_ = true
+        value = "foo"
+        index = 1L
+        values += "foo"
+        newValues += "foo"
+        builder = true
+        k[1] = 1
+        v["foo"] = "foo"
+        key["foo"] = 1
+        map[1] = "foo"
+        pairs["foo"] = 1
+        LeadingUnderscore = "foo"
+        option = 1
+      }
+    ).isEqualTo(
+      EvilNamesProto3.newBuilder()
+        .setInitialized(true)
+        .setHasFoo(true)
+        .setBar("foo")
+        .setIsInitialized(true)
+        .setFooBar("foo")
+        .addALLCAPS("foo")
+        .putALLCAPSMAP(1, true)
+        .setHasUnderbarPrecedingNumeric1Foo(true)
+        .setHasUnderbarPrecedingNumeric42Bar(true)
+        .setHasUnderbarPrecedingNumeric123Foo42BarBaz(true)
+        .addExtension("foo")
+        .setClass_("foo")
+        .setInt(1.0)
+        .setLong(true)
+        .setBoolean(1L)
+        .setSealed("foo")
+        .setInterface(1F)
+        .setIn(1)
+        .setObject("foo")
+        .setCachedSize_("foo")
+        .setSerializedSize_(true)
+        .setValue("foo")
+        .setIndex(1L)
+        .addValues("foo")
+        .addNewValues("foo")
+        .setBuilder(true)
+        .putK(1, 1)
+        .putV("foo", "foo")
+        .putKey("foo", 1)
+        .putMap(1, "foo")
+        .putPairs("foo", 1)
+        .setLeadingUnderscore("foo")
+        .setOption(1)
+        .build()
+    )
+
+    assertThat(class_ {}).isEqualTo(Class.newBuilder().build())
+  }
+
+  @Test
+  fun testHardKeywordGettersAndSetters() {
+    hardKeywordsAllTypes {
+      as_ = 1
+      assertThat(as_).isEqualTo(1)
+
+      in_ = "foo"
+      assertThat(in_).isEqualTo("foo")
+
+      break_ = HardKeywordsAllTypes.NestedEnum.FOO
+      assertThat(break_).isEqualTo(HardKeywordsAllTypes.NestedEnum.FOO)
+
+      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
+      assertThat(do_).isEqualTo(HardKeywordsAllTypesKt.nestedMessage { while_ = 1 })
+
+      continue_[1] = 1
+      assertThat(continue_[1]).isEqualTo(1)
+
+      else_ += 1
+      assertThat(else_).isEqualTo(listOf(1))
+
+      for_ += "foo"
+      assertThat(for_).isEqualTo(listOf("foo"))
+
+      fun_ += HardKeywordsAllTypes.NestedEnum.FOO
+      assertThat(fun_).isEqualTo(listOf(HardKeywordsAllTypes.NestedEnum.FOO))
+
+      if_ += HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
+      assertThat(if_).isEqualTo(listOf(HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }))
+    }
+  }
+
+  @Test
+  fun testHardKeywordHazzers() {
+    hardKeywordsAllTypes {
+      as_ = 1
+      assertThat(hasAs_()).isTrue()
+
+      in_ = "foo"
+      assertThat(hasIn_()).isTrue()
+
+      break_ = HardKeywordsAllTypes.NestedEnum.FOO
+      assertThat(hasBreak_()).isTrue()
+
+      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
+      assertThat(hasDo_()).isTrue()
+    }
+  }
+
+  @Test
+  fun testHardKeywordClears() {
+    hardKeywordsAllTypes {
+      as_ = 1
+      clearAs_()
+      assertThat(hasAs_()).isFalse()
+
+      in_ = "foo"
+      clearIn_()
+      assertThat(hasIn_()).isFalse()
+
+      break_ = HardKeywordsAllTypes.NestedEnum.FOO
+      clearBreak_()
+      assertThat(hasBreak_()).isFalse()
+
+      do_ = HardKeywordsAllTypesKt.nestedMessage { while_ = 1 }
+      clearDo_()
+      assertThat(hasDo_()).isFalse()
+    }
+  }
+
+  @Test
+  fun testMultipleFiles() {
+    assertThat(
+      multipleFilesMessageA {}
+    ).isEqualTo(
+      MultipleFilesMessageA.newBuilder().build()
+    )
+
+    assertThat(
+      multipleFilesMessageB {}
+    ).isEqualTo(
+      MultipleFilesMessageB.newBuilder().build()
+    )
+  }
+}
--- a/java/core/src/test/proto/com/google/protobuf/evil_names_proto3.proto
+++ b/java/core/src/test/proto/com/google/protobuf/evil_names_proto3.proto
@ -1,9 +1,8 @@
-// LINT: LEGACY_NAMES
 syntax = "proto3";

-package protobuf.kotlin.generator;
+package evil_names_proto3;

-option java_package = "com.google.protobuf.kotlin.generator";
+option java_package = "evil_names_proto3";

 message EvilNamesProto3 {
  bool initialized = 1;
--- a/java/core/src/test/proto/com/google/protobuf/example_extensible_message.proto
+++ b/java/core/src/test/proto/com/google/protobuf/example_extensible_message.proto
@ -1,8 +1,8 @@
 syntax = "proto2";

-package protobuf.kotlin.test;
+package example_extensible_message;

-option java_package = "com.google.protobuf.kotlin.test";
+option java_package = "example_extensible_message";
 option java_multiple_files = true;

 message ExampleExtensibleMessage {
--- a/java/core/src/test/proto/com/google/protobuf/multiple_files_proto3.proto
+++ b/java/core/src/test/proto/com/google/protobuf/multiple_files_proto3.proto
@ -1,8 +1,8 @@
 syntax = "proto3";

-package protobuf.kotlin.generator;
+package multiple_files_proto3;

-option java_package = "com.google.protobuf.kotlin.generator";
+option java_package = "multiple_files_proto3";
 option java_multiple_files = true;

 enum NestedEnum { FOO = 0; }
--- a/java/lite/generate-test-sources-build.xml
+++ b/java/lite/generate-test-sources-build.xml
@ -4,6 +4,8 @@
        <arg value="--java_out=lite:${generated.testsources.dir}"/>
        <arg value="--proto_path=${protobuf.source.dir}"/>
        <arg value="--proto_path=${protobuf.basedir}/java/core/${test.proto.dir}"/>
+        <arg value="--experimental_allow_proto3_optional"/>
+        <arg value="${protobuf.source.dir}/google/protobuf/map_lite_unittest.proto"/>
        <arg value="${protobuf.source.dir}/google/protobuf/unittest.proto"/>
        <arg value="${protobuf.source.dir}/google/protobuf/unittest_import.proto"/>
        <arg value="${protobuf.source.dir}/google/protobuf/unittest_import_lite.proto"/>
@ -20,6 +22,9 @@
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/any_test.proto"/>
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/cached_field_size_test.proto"/>
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/deprecated_file.proto"/>
+        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/evil_names_proto2.proto"/>
+        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/evil_names_proto3.proto"/>
+        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/example_extensible_message.proto"/>
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/field_presence_test.proto"/>
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/lazy_fields_lite.proto"/>
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/lite_equals_and_hash.proto"/>
@ -29,6 +34,7 @@
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/map_lite_test.proto"/>
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/map_test.proto"/>
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/message_lite_extension_util_test.proto"/>
+        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/multiple_files_proto3.proto"/>
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/nested_builders_test.proto"/>
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/nested_extension.proto"/>
        <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/nested_extension_lite.proto"/>
@ -52,7 +58,13 @@
      <arg value="--kotlin_out=lite:${generated.testsources.dir}"/>
      <arg value="--proto_path=${protobuf.source.dir}"/>
      <arg value="--proto_path=${protobuf.basedir}/java/core/${test.proto.dir}"/>
-      <arg value="${protobuf.source.dir}/google/protobuf/unittest.proto"/>
+      <arg value="--experimental_allow_proto3_optional"/>
+      <arg value="${protobuf.source.dir}/google/protobuf/map_lite_unittest.proto"/>
+      <arg value="${protobuf.source.dir}/google/protobuf/unittest_lite.proto"/>
      <arg value="${protobuf.source.dir}/google/protobuf/unittest_proto3.proto"/>
+      <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/evil_names_proto2.proto"/>
+      <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/evil_names_proto3.proto"/>
+      <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/example_extensible_message.proto"/>
+      <arg value="${protobuf.basedir}/java/core/${test.proto.dir}/com/google/protobuf/multiple_files_proto3.proto"/>
    </exec>
 </project>
--- a/java/lite/pom.xml
+++ b/java/lite/pom.xml
@ -16,6 +16,10 @@
    not guarantee API/ABI stability.
  </description>

+  <properties>
+    <kotlin.version>1.4.31</kotlin.version>
+  </properties>
+
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
@ -37,11 +41,26 @@
      <artifactId>guava</artifactId>
      <scope>test</scope>
    </dependency>
+    <dependency>
+      <groupId>com.google.guava</groupId>
+      <artifactId>guava-testlib</artifactId>
+      <scope>test</scope>
+    </dependency>
    <dependency>
      <groupId>com.google.truth</groupId>
      <artifactId>truth</artifactId>
      <scope>test</scope>
    </dependency>
+    <dependency>
+      <groupId>org.jetbrains.kotlin</groupId>
+      <artifactId>kotlin-stdlib-jdk7</artifactId>
+      <version>${kotlin.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>org.jetbrains.kotlin</groupId>
+      <artifactId>kotlin-test</artifactId>
+      <version>${kotlin.version}</version>
+    </dependency>
  </dependencies>

  <build>
@ -179,6 +198,19 @@
                    <include>Writer.java</include>
                  </includes>
                </resource>
+                <resource>
+                  <directory>${basedir}/../core/src/main/kotlin/com/google/protobuf</directory>
+                  <includes>
+                    <include>DslList.kt</include>
+                    <include>DslMap.kt</include>
+                    <include>DslProxy.kt</include>
+                    <include>ExtendableMessageLiteExtensions.kt</include>
+                    <include>ExtensionList.kt</include>
+                    <include>OnlyForUseByGeneratedProtoCode.kt</include>
+                    <include>ProtoDslMarker.kt</include>
+                    <include>UnmodifiableCollections.kt</include>
+                  </includes>
+                </resource>
              </resources>
            </configuration>
          </execution>
@ -238,6 +270,13 @@
                    <exclude>WireFormatTest.java</exclude>
                  </excludes>
                </resource>
+                <resource>
+                  <directory>${basedir}/../core/src/test/kotlin/com/google/protobuf</directory>
+                  <excludes>
+                    <exclude>ExtendableMessageExtensionsTest.kt</exclude>
+                    <exclude>Proto2Test.kt</exclude>
+                  </excludes>
+                </resource>
              </resources>
            </configuration>
          </execution>
@ -326,8 +365,19 @@
      <plugin>
        <groupId>org.jetbrains.kotlin</groupId>
        <artifactId>kotlin-maven-plugin</artifactId>
+        <version>${kotlin.version}</version>
        <extensions>true</extensions>
        <executions>
+          <execution>
+            <id>compile</id>
+            <goals> <goal>compile</goal> </goals>
+            <configuration>
+              <sourceDirs>
+                <sourceDir>${generated.sources.dir}/com/google/protobuf</sourceDir>
+                <sourceDir>${project.basedir}/src/main/kotlin</sourceDir>
+              </sourceDirs>
+            </configuration>
+          </execution>
          <execution>
            <id>test-compile</id>
            <goals> <goal>test-compile</goal> </goals>
--- a/java/lite/src/test/kotlin/com/google/protobuf/ExtendableMessageLiteExtensionsTest.kt
+++ b/java/lite/src/test/kotlin/com/google/protobuf/ExtendableMessageLiteExtensionsTest.kt
@ -1,8 +1,8 @@
 package com.google.protobuf.kotlin

 import com.google.common.truth.Truth.assertThat
-import com.google.protobuf.kotlin.test.ExampleExtensibleMessage
-import com.google.protobuf.kotlin.test.Test as TestProto
+import example_extensible_message.ExampleExtensibleMessage
+import example_extensible_message.ExampleExtensibleMessageOuterClass as TestProto
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
--- a/java/lite/src/test/kotlin/com/google/protobuf/Proto2LiteTest.kt
+++ b/java/lite/src/test/kotlin/com/google/protobuf/Proto2LiteTest.kt
@ -16,22 +16,22 @@ import com.google.protobuf.UnittestLite.TestEmptyMessageLite
 import com.google.protobuf.UnittestLite.TestEmptyMessageWithExtensionsLite
 import com.google.protobuf.copy
 import com.google.protobuf.foreignMessageLite
-import com.google.protobuf.kotlin.generator.EvilNamesProto2OuterClass.EvilNamesProto2
-import com.google.protobuf.kotlin.generator.EvilNamesProto2OuterClass.HardKeywordsAllTypes
-import com.google.protobuf.kotlin.generator.EvilNamesProto2OuterClass.Interface
-import com.google.protobuf.kotlin.generator.HardKeywordsAllTypesKt
-import com.google.protobuf.kotlin.generator.evilNamesProto2
-import com.google.protobuf.kotlin.generator.hardKeywordsAllTypes
-import com.google.protobuf.kotlin.generator.interface_
+import evil_names_proto2.EvilNamesProto2OuterClass.EvilNamesProto2
+import evil_names_proto2.EvilNamesProto2OuterClass.HardKeywordsAllTypes
+import evil_names_proto2.EvilNamesProto2OuterClass.Interface
+import evil_names_proto2.HardKeywordsAllTypesKt
+import evil_names_proto2.evilNamesProto2
+import evil_names_proto2.hardKeywordsAllTypes
+import evil_names_proto2.interface_
 import com.google.protobuf.optionalGroupExtensionLite
 import com.google.protobuf.repeatedGroupExtensionLite
 import com.google.protobuf.testAllExtensionsLite
 import com.google.protobuf.testAllTypesLite
 import com.google.protobuf.testEmptyMessageLite
 import com.google.protobuf.testEmptyMessageWithExtensionsLite
-import com.google.protos.proto2_unittest.MapLiteUnittest.MapEnumLite
-import com.google.protos.proto2_unittest.MapLiteUnittest.TestMapLite
-import com.google.protos.proto2_unittest.testMapLite
+import protobuf_unittest.MapLiteUnittest.MapEnumLite
+import protobuf_unittest.MapLiteUnittest.TestMapLite
+import protobuf_unittest.testMapLite
 import org.junit.Test
 import org.junit.runner.RunWith
 import org.junit.runners.JUnit4
@ -452,34 +452,37 @@ class Proto2LiteTest {
        this[UnittestLite.repeatedImportEnumExtensionLite].add(ImportEnumLite.IMPORT_LITE_BAR)
        this[UnittestLite.repeatedStringPieceExtensionLite].add("224")
        this[UnittestLite.repeatedCordExtensionLite].add("225")
-        this[UnittestLite.repeatedInt32ExtensionLite] += 301
-        this[UnittestLite.repeatedInt64ExtensionLite] += 302L
-        this[UnittestLite.repeatedUint32ExtensionLite] += 303
-        this[UnittestLite.repeatedUint64ExtensionLite] += 304L
-        this[UnittestLite.repeatedSint32ExtensionLite] += 305
-        this[UnittestLite.repeatedSint64ExtensionLite] += 306L
-        this[UnittestLite.repeatedFixed32ExtensionLite] += 307
-        this[UnittestLite.repeatedFixed64ExtensionLite] += 308L
-        this[UnittestLite.repeatedSfixed32ExtensionLite] += 309
-        this[UnittestLite.repeatedSfixed64ExtensionLite] += 310L
-        this[UnittestLite.repeatedFloatExtensionLite] += 311F
-        this[UnittestLite.repeatedDoubleExtensionLite] += 312.0
-        this[UnittestLite.repeatedBoolExtensionLite] += false
-        this[UnittestLite.repeatedStringExtensionLite] += "315"
-        this[UnittestLite.repeatedBytesExtensionLite] += toBytes("316")
-        this[UnittestLite.repeatedGroupExtensionLite] += repeatedGroupExtensionLite { a = 317 }
-        this[UnittestLite.repeatedNestedMessageExtensionLite] +=
+        this[UnittestLite.repeatedInt32ExtensionLite].add(301)
+        this[UnittestLite.repeatedInt64ExtensionLite].add(302L)
+        this[UnittestLite.repeatedUint32ExtensionLite].add(303)
+        this[UnittestLite.repeatedUint64ExtensionLite].add(304L)
+        this[UnittestLite.repeatedSint32ExtensionLite].add(305)
+        this[UnittestLite.repeatedSint64ExtensionLite].add(306L)
+        this[UnittestLite.repeatedFixed32ExtensionLite].add(307)
+        this[UnittestLite.repeatedFixed64ExtensionLite].add(308L)
+        this[UnittestLite.repeatedSfixed32ExtensionLite].add(309)
+        this[UnittestLite.repeatedSfixed64ExtensionLite].add(310L)
+        this[UnittestLite.repeatedFloatExtensionLite].add(311F)
+        this[UnittestLite.repeatedDoubleExtensionLite].add(312.0)
+        this[UnittestLite.repeatedBoolExtensionLite].add(false)
+        this[UnittestLite.repeatedStringExtensionLite].add("315")
+        this[UnittestLite.repeatedBytesExtensionLite].add(toBytes("316"))
+        this[UnittestLite.repeatedGroupExtensionLite].add(repeatedGroupExtensionLite { a = 317 })
+        this[UnittestLite.repeatedNestedMessageExtensionLite].add(
          TestAllTypesLiteKt.nestedMessage { bb = 318 }
-        this[UnittestLite.repeatedForeignMessageExtensionLite] += foreignMessageLite { c = 319 }
-        this[UnittestLite.repeatedImportMessageExtensionLite] +=
+	)
+        this[UnittestLite.repeatedForeignMessageExtensionLite].add(foreignMessageLite { c = 319 })
+        this[UnittestLite.repeatedImportMessageExtensionLite].add(
          ImportMessageLite.newBuilder().setD(320).build()
-        this[UnittestLite.repeatedLazyMessageExtensionLite] +=
+	)
+        this[UnittestLite.repeatedLazyMessageExtensionLite].add(
          TestAllTypesLiteKt.nestedMessage { bb = 327 }
-        this[UnittestLite.repeatedNestedEnumExtensionLite] += NestedEnum.BAZ
-        this[UnittestLite.repeatedForeignEnumExtensionLite] += ForeignEnumLite.FOREIGN_LITE_BAZ
-        this[UnittestLite.repeatedImportEnumExtensionLite] += ImportEnumLite.IMPORT_LITE_BAZ
-        this[UnittestLite.repeatedStringPieceExtensionLite] += "324"
-        this[UnittestLite.repeatedCordExtensionLite] += "325"
+	)
+        this[UnittestLite.repeatedNestedEnumExtensionLite].add(NestedEnum.BAZ)
+        this[UnittestLite.repeatedForeignEnumExtensionLite].add(ForeignEnumLite.FOREIGN_LITE_BAZ)
+        this[UnittestLite.repeatedImportEnumExtensionLite].add(ImportEnumLite.IMPORT_LITE_BAZ)
+        this[UnittestLite.repeatedStringPieceExtensionLite].add("324")
+        this[UnittestLite.repeatedCordExtensionLite].add("325")
        this[UnittestLite.defaultInt32ExtensionLite] = 401
        this[UnittestLite.defaultInt64ExtensionLite] = 402L
        this[UnittestLite.defaultUint32ExtensionLite] = 403
@ -539,14 +542,14 @@ class Proto2LiteTest {
    testAllExtensionsLite {
      this[UnittestLite.repeatedInt32ExtensionLite].addAll(listOf(1, 2))
      assertThat(this[UnittestLite.repeatedInt32ExtensionLite]).isEqualTo(listOf(1, 2))
-      this[UnittestLite.repeatedInt32ExtensionLite] += listOf(3, 4)
+      this[UnittestLite.repeatedInt32ExtensionLite].addAll(listOf(3, 4))
      assertThat(this[UnittestLite.repeatedInt32ExtensionLite]).isEqualTo(listOf(1, 2, 3, 4))
      this[UnittestLite.repeatedInt32ExtensionLite][0] = 5
      assertThat(this[UnittestLite.repeatedInt32ExtensionLite]).isEqualTo(listOf(5, 2, 3, 4))

      this[UnittestLite.repeatedStringExtensionLite].addAll(listOf("1", "2"))
      assertThat(this[UnittestLite.repeatedStringExtensionLite]).isEqualTo(listOf("1", "2"))
-      this[UnittestLite.repeatedStringExtensionLite] += listOf("3", "4")
+      this[UnittestLite.repeatedStringExtensionLite].addAll(listOf("3", "4"))
      assertThat(this[UnittestLite.repeatedStringExtensionLite])
        .isEqualTo(listOf("1", "2", "3", "4"))
      this[UnittestLite.repeatedStringExtensionLite][0] = "5"
@ -565,11 +568,12 @@ class Proto2LiteTest {
          repeatedGroupExtensionLite { a = 2 }
        )
      )
-      this[UnittestLite.repeatedGroupExtensionLite] +=
+      this[UnittestLite.repeatedGroupExtensionLite].addAll(
        listOf(
          repeatedGroupExtensionLite { a = 3 },
          repeatedGroupExtensionLite { a = 4 }
        )
+      )
      assertThat(this[UnittestLite.repeatedGroupExtensionLite]).isEqualTo(
        listOf(
          repeatedGroupExtensionLite { a = 1 },
@ -594,8 +598,9 @@ class Proto2LiteTest {
      assertThat(this[UnittestLite.repeatedNestedMessageExtensionLite]).isEqualTo(
        listOf(nestedMessage { bb = 1 }, nestedMessage { bb = 2 })
      )
-      this[UnittestLite.repeatedNestedMessageExtensionLite] +=
+      this[UnittestLite.repeatedNestedMessageExtensionLite].addAll(
        listOf(nestedMessage { bb = 3 }, nestedMessage { bb = 4 })
+      )
      assertThat(this[UnittestLite.repeatedNestedMessageExtensionLite]).isEqualTo(
        listOf(
          nestedMessage { bb = 1 },
@ -618,7 +623,7 @@ class Proto2LiteTest {
        .addAll(listOf(NestedEnum.FOO, NestedEnum.BAR))
      assertThat(this[UnittestLite.repeatedNestedEnumExtensionLite])
        .isEqualTo(listOf(NestedEnum.FOO, NestedEnum.BAR))
-      this[UnittestLite.repeatedNestedEnumExtensionLite] += listOf(NestedEnum.BAZ, NestedEnum.FOO)
+      this[UnittestLite.repeatedNestedEnumExtensionLite].addAll(listOf(NestedEnum.BAZ, NestedEnum.FOO))
      assertThat(this[UnittestLite.repeatedNestedEnumExtensionLite]).isEqualTo(
        listOf(NestedEnum.FOO, NestedEnum.BAR, NestedEnum.BAZ, NestedEnum.FOO)
      )