Rename mixin protos and add a check for undefined mixin name

lib/src/descriptor.pbenum.dart

Index: lib/src/descriptor.pbenum.dart
diff --git a/lib/src/descriptor.pbenum.dart b/lib/src/descriptor.pbenum.dart
new file mode 100644
index 0000000000000000000000000000000000000000..a81734005b48d69b65091ab53c45c9a1d57c5521
--- /dev/null
+++ b/lib/src/descriptor.pbenum.dart
@@ -0,0 +1,113 @@
+///
+//  Generated code. Do not modify.
+///
+library proto2_descriptor_pbenum;
+
+import 'package:protobuf/protobuf.dart';
+
+class FieldDescriptorProto_Type extends ProtobufEnum {
+  static const FieldDescriptorProto_Type TYPE_DOUBLE = const FieldDescriptorProto_Type._(1, 'TYPE_DOUBLE');
+  static const FieldDescriptorProto_Type TYPE_FLOAT = const FieldDescriptorProto_Type._(2, 'TYPE_FLOAT');
+  static const FieldDescriptorProto_Type TYPE_INT64 = const FieldDescriptorProto_Type._(3, 'TYPE_INT64');
+  static const FieldDescriptorProto_Type TYPE_UINT64 = const FieldDescriptorProto_Type._(4, 'TYPE_UINT64');
+  static const FieldDescriptorProto_Type TYPE_INT32 = const FieldDescriptorProto_Type._(5, 'TYPE_INT32');
+  static const FieldDescriptorProto_Type TYPE_FIXED64 = const FieldDescriptorProto_Type._(6, 'TYPE_FIXED64');
+  static const FieldDescriptorProto_Type TYPE_FIXED32 = const FieldDescriptorProto_Type._(7, 'TYPE_FIXED32');
+  static const FieldDescriptorProto_Type TYPE_BOOL = const FieldDescriptorProto_Type._(8, 'TYPE_BOOL');
+  static const FieldDescriptorProto_Type TYPE_STRING = const FieldDescriptorProto_Type._(9, 'TYPE_STRING');
+  static const FieldDescriptorProto_Type TYPE_GROUP = const FieldDescriptorProto_Type._(10, 'TYPE_GROUP');
+  static const FieldDescriptorProto_Type TYPE_MESSAGE = const FieldDescriptorProto_Type._(11, 'TYPE_MESSAGE');
+  static const FieldDescriptorProto_Type TYPE_BYTES = const FieldDescriptorProto_Type._(12, 'TYPE_BYTES');
+  static const FieldDescriptorProto_Type TYPE_UINT32 = const FieldDescriptorProto_Type._(13, 'TYPE_UINT32');
+  static const FieldDescriptorProto_Type TYPE_ENUM = const FieldDescriptorProto_Type._(14, 'TYPE_ENUM');
+  static const FieldDescriptorProto_Type TYPE_SFIXED32 = const FieldDescriptorProto_Type._(15, 'TYPE_SFIXED32');
+  static const FieldDescriptorProto_Type TYPE_SFIXED64 = const FieldDescriptorProto_Type._(16, 'TYPE_SFIXED64');
+  static const FieldDescriptorProto_Type TYPE_SINT32 = const FieldDescriptorProto_Type._(17, 'TYPE_SINT32');
+  static const FieldDescriptorProto_Type TYPE_SINT64 = const FieldDescriptorProto_Type._(18, 'TYPE_SINT64');
+
+  static const List<FieldDescriptorProto_Type> values = const <FieldDescriptorProto_Type> [
+    TYPE_DOUBLE,
+    TYPE_FLOAT,
+    TYPE_INT64,
+    TYPE_UINT64,
+    TYPE_INT32,
+    TYPE_FIXED64,
+    TYPE_FIXED32,
+    TYPE_BOOL,
+    TYPE_STRING,
+    TYPE_GROUP,
+    TYPE_MESSAGE,
+    TYPE_BYTES,
+    TYPE_UINT32,
+    TYPE_ENUM,
+    TYPE_SFIXED32,
+    TYPE_SFIXED64,
+    TYPE_SINT32,
+    TYPE_SINT64,
+  ];
+
+  static final Map<int, dynamic> _byValue = ProtobufEnum.initByValue(values);
+  static FieldDescriptorProto_Type valueOf(int value) => _byValue[value] as FieldDescriptorProto_Type;
+  static void $checkItem(FieldDescriptorProto_Type v) {
+    if (v is !FieldDescriptorProto_Type) checkItemFailed(v, 'FieldDescriptorProto_Type');
+  }
+
+  const FieldDescriptorProto_Type._(int v, String n) : super(v, n);
+}
+
+class FieldDescriptorProto_Label extends ProtobufEnum {
+  static const FieldDescriptorProto_Label LABEL_OPTIONAL = const FieldDescriptorProto_Label._(1, 'LABEL_OPTIONAL');
+  static const FieldDescriptorProto_Label LABEL_REQUIRED = const FieldDescriptorProto_Label._(2, 'LABEL_REQUIRED');
+  static const FieldDescriptorProto_Label LABEL_REPEATED = const FieldDescriptorProto_Label._(3, 'LABEL_REPEATED');
+
+  static const List<FieldDescriptorProto_Label> values = const <FieldDescriptorProto_Label> [
+    LABEL_OPTIONAL,
+    LABEL_REQUIRED,
+    LABEL_REPEATED,
+  ];
+
+  static final Map<int, dynamic> _byValue = ProtobufEnum.initByValue(values);
+  static FieldDescriptorProto_Label valueOf(int value) => _byValue[value] as FieldDescriptorProto_Label;
+  static void $checkItem(FieldDescriptorProto_Label v) {
+    if (v is !FieldDescriptorProto_Label) checkItemFailed(v, 'FieldDescriptorProto_Label');
+  }
+
+  const FieldDescriptorProto_Label._(int v, String n) : super(v, n);
+}
+
+class FileOptions_OptimizeMode extends ProtobufEnum {
+  static const FileOptions_OptimizeMode SPEED = const FileOptions_OptimizeMode._(1, 'SPEED');
+  static const FileOptions_OptimizeMode CODE_SIZE = const FileOptions_OptimizeMode._(2, 'CODE_SIZE');
+  static const FileOptions_OptimizeMode LITE_RUNTIME = const FileOptions_OptimizeMode._(3, 'LITE_RUNTIME');
+
+  static const List<FileOptions_OptimizeMode> values = const <FileOptions_OptimizeMode> [
+    SPEED,
+    CODE_SIZE,
+    LITE_RUNTIME,
+  ];
+
+  static final Map<int, dynamic> _byValue = ProtobufEnum.initByValue(values);
+  static FileOptions_OptimizeMode valueOf(int value) => _byValue[value] as FileOptions_OptimizeMode;
+  static void $checkItem(FileOptions_OptimizeMode v) {
+    if (v is !FileOptions_OptimizeMode) checkItemFailed(v, 'FileOptions_OptimizeMode');
+  }
+
+  const FileOptions_OptimizeMode._(int v, String n) : super(v, n);
+}
+
+class FieldOptions_CType extends ProtobufEnum {
+  static const FieldOptions_CType STRING = const FieldOptions_CType._(0, 'STRING');
+
+  static const List<FieldOptions_CType> values = const <FieldOptions_CType> [
+    STRING,
+  ];
+
+  static final Map<int, dynamic> _byValue = ProtobufEnum.initByValue(values);
+  static FieldOptions_CType valueOf(int value) => _byValue[value] as FieldOptions_CType;
+  static void $checkItem(FieldOptions_CType v) {
+    if (v is !FieldOptions_CType) checkItemFailed(v, 'FieldOptions_CType');
+  }
+
+  const FieldOptions_CType._(int v, String n) : super(v, n);
+}
+