diff --git a/packages/pigeon/CHANGELOG.md b/packages/pigeon/CHANGELOG.md
index a53b3b7..97bd5df 100644
--- a/packages/pigeon/CHANGELOG.md
+++ b/packages/pigeon/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 3.0.0
+
+* **BREAKING CHANGE**: Removes the `--dart_null_safety` flag. Generated Dart
+  now always uses nullability annotations, and thus requires Dart 2.12 or later.
+
 ## 2.0.4
 
 * Fixes bug where Dart `FlutterApi`s would assert that a nullable argument was nonnull.
@@ -9,7 +14,7 @@
 ## 2.0.2
 
 * Fixes Java crash for nullable nested type.
-  
+
 * ## 2.0.1
 
 * Adds support for TaskQueues for serial background execution.
diff --git a/packages/pigeon/lib/dart_generator.dart b/packages/pigeon/lib/dart_generator.dart
index 0325c29..982044c 100644
--- a/packages/pigeon/lib/dart_generator.dart
+++ b/packages/pigeon/lib/dart_generator.dart
@@ -9,10 +9,7 @@
 /// Options that control how Dart code will be generated.
 class DartOptions {
   /// Constructor for DartOptions.
-  const DartOptions({this.isNullSafe = true, this.copyrightHeader});
-
-  /// Determines if the generated code has null safety annotations (Dart >=2.12 required).
-  final bool isNullSafe;
+  const DartOptions({this.copyrightHeader});
 
   /// A copyright header that will get prepended to generated code.
   final Iterable<String>? copyrightHeader;
@@ -23,7 +20,6 @@
     final Iterable<dynamic>? copyrightHeader =
         map['copyrightHeader'] as Iterable<dynamic>?;
     return DartOptions(
-      isNullSafe: map['isNullSafe'] as bool? ?? true,
       copyrightHeader: copyrightHeader?.cast<String>(),
     );
   }
@@ -32,7 +28,6 @@
   /// `x = DartOptions.fromMap(x.toMap())`.
   Map<String, Object> toMap() {
     final Map<String, Object> result = <String, Object>{
-      if (isNullSafe != null) 'isNullSafe': isNullSafe,
       if (copyrightHeader != null) 'copyrightHeader': copyrightHeader!,
     };
     return result;
@@ -102,17 +97,17 @@
 }
 
 /// Creates a Dart type where all type arguments are [Objects].
-String _makeGenericTypeArguments(TypeDeclaration type, String nullTag) {
+String _makeGenericTypeArguments(TypeDeclaration type) {
   return type.typeArguments.isNotEmpty
-      ? '${type.baseName}<${type.typeArguments.map<String>((TypeDeclaration e) => 'Object$nullTag').join(', ')}>'
-      : _addGenericTypes(type, nullTag);
+      ? '${type.baseName}<${type.typeArguments.map<String>((TypeDeclaration e) => 'Object?').join(', ')}>'
+      : _addGenericTypes(type);
 }
 
 /// Creates a `.cast<>` call for an type. Returns an empty string if the
 /// type has no type arguments.
-String _makeGenericCastCall(TypeDeclaration type, String nullTag) {
+String _makeGenericCastCall(TypeDeclaration type) {
   return type.typeArguments.isNotEmpty
-      ? '.cast<${_flattenTypeArguments(type.typeArguments, nullTag)}>()'
+      ? '.cast<${_flattenTypeArguments(type.typeArguments)}>()'
       : '';
 }
 
@@ -125,16 +120,15 @@
     field.name.isEmpty ? 'arg$count' : field.name;
 
 /// Generates the arguments code for [func]
-/// Example: (func, getArgumentName, nullTag) -> 'String? foo, int bar'
+/// Example: (func, getArgumentName) -> 'String? foo, int bar'
 String _getMethodArgumentsSignature(
   Method func,
   String Function(int index, NamedType arg) getArgumentName,
-  String nullTag,
 ) {
   return func.arguments.isEmpty
       ? ''
       : indexMap(func.arguments, (int index, NamedType arg) {
-          final String type = _addGenericTypesNullable(arg.type, nullTag);
+          final String type = _addGenericTypesNullable(arg.type);
           final String argName = getArgumentName(index, arg);
           return '$type $argName';
         }).join(', ');
@@ -154,8 +148,6 @@
   final String codecName = _getCodecName(api);
   _writeCodec(indent, codecName, api, root);
   indent.addln('');
-  final String nullTag = opt.isNullSafe ? '?' : '';
-  final String unwrapOperator = opt.isNullSafe ? '!' : '';
   bool first = true;
   indent.write('class ${api.name} ');
   indent.scoped('{', '}', () {
@@ -163,9 +155,9 @@
 /// Constructor for [${api.name}].  The [binaryMessenger] named argument is
 /// available for dependency injection.  If it is left null, the default
 /// BinaryMessenger will be used which routes to the host platform.
-${api.name}({BinaryMessenger$nullTag binaryMessenger}) : _binaryMessenger = binaryMessenger;
+${api.name}({BinaryMessenger? binaryMessenger}) : _binaryMessenger = binaryMessenger;
 
-final BinaryMessenger$nullTag _binaryMessenger;
+final BinaryMessenger? _binaryMessenger;
 ''');
 
     indent.writeln('static const MessageCodec<Object?> codec = $codecName();');
@@ -183,41 +175,39 @@
             _getSafeArgumentName(index, type);
         final Iterable<String> argNames = indexMap(func.arguments, argNameFunc);
         sendArgument = '<Object?>[${argNames.join(', ')}]';
-        argSignature = _getMethodArgumentsSignature(func, argNameFunc, nullTag);
+        argSignature = _getMethodArgumentsSignature(func, argNameFunc);
       }
       indent.write(
-        'Future<${_addGenericTypesNullable(func.returnType, nullTag)}> ${func.name}($argSignature) async ',
+        'Future<${_addGenericTypesNullable(func.returnType)}> ${func.name}($argSignature) async ',
       );
       indent.scoped('{', '}', () {
         final String channelName = makeChannelName(api, func);
         indent.writeln(
-            'final BasicMessageChannel<Object$nullTag> channel = BasicMessageChannel<Object$nullTag>(');
+            'final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(');
         indent.nest(2, () {
           indent.writeln(
             '\'$channelName\', codec, binaryMessenger: _binaryMessenger);',
           );
         });
-        final String returnType =
-            _makeGenericTypeArguments(func.returnType, nullTag);
-        final String castCall = _makeGenericCastCall(func.returnType, nullTag);
+        final String returnType = _makeGenericTypeArguments(func.returnType);
+        final String castCall = _makeGenericCastCall(func.returnType);
         const String accessor = 'replyMap[\'${Keys.result}\']';
-        final String unwrapper =
-            func.returnType.isNullable ? '' : unwrapOperator;
+        final String unwrapper = func.returnType.isNullable ? '' : '!';
         final String returnStatement = func.returnType.isVoid
             ? 'return;'
-            : 'return ($accessor as $returnType$nullTag)$unwrapper$castCall;';
+            : 'return ($accessor as $returnType?)$unwrapper$castCall;';
         indent.format('''
-final Map<Object$nullTag, Object$nullTag>$nullTag replyMap =\n\t\tawait channel.send($sendArgument) as Map<Object$nullTag, Object$nullTag>$nullTag;
+final Map<Object?, Object?>? replyMap =\n\t\tawait channel.send($sendArgument) as Map<Object?, Object?>?;
 if (replyMap == null) {
 \tthrow PlatformException(
 \t\tcode: 'channel-error',
 \t\tmessage: 'Unable to establish connection on channel.',
 \t);
 } else if (replyMap['error'] != null) {
-\tfinal Map<Object$nullTag, Object$nullTag> error = (replyMap['${Keys.error}'] as Map<Object$nullTag, Object$nullTag>$nullTag)$unwrapOperator;
+\tfinal Map<Object?, Object?> error = (replyMap['${Keys.error}'] as Map<Object?, Object?>?)!;
 \tthrow PlatformException(
-\t\tcode: (error['${Keys.errorCode}'] as String$nullTag)$unwrapOperator,
-\t\tmessage: error['${Keys.errorMessage}'] as String$nullTag,
+\t\tcode: (error['${Keys.errorCode}'] as String?)!,
+\t\tmessage: error['${Keys.errorMessage}'] as String?,
 \t\tdetails: error['${Keys.errorDetails}'],
 \t);''');
         // On iOS we can return nil from functions to accommodate error
@@ -260,8 +250,6 @@
   assert(api.location == ApiLocation.flutter);
   final String codecName = _getCodecName(api);
   _writeCodec(indent, codecName, api, root);
-  final String nullTag = opt.isNullSafe ? '?' : '';
-  final String unwrapOperator = opt.isNullSafe ? '!' : '';
   indent.write('abstract class ${api.name} ');
   indent.scoped('{', '}', () {
     indent.writeln('static const MessageCodec<Object?> codec = $codecName();');
@@ -269,23 +257,22 @@
     for (final Method func in api.methods) {
       final bool isAsync = func.isAsynchronous;
       final String returnType = isAsync
-          ? 'Future<${_addGenericTypesNullable(func.returnType, nullTag)}>'
-          : _addGenericTypesNullable(func.returnType, nullTag);
+          ? 'Future<${_addGenericTypesNullable(func.returnType)}>'
+          : _addGenericTypesNullable(func.returnType);
       final String argSignature = _getMethodArgumentsSignature(
         func,
         _getArgumentName,
-        nullTag,
       );
       indent.writeln('$returnType ${func.name}($argSignature);');
     }
     indent.write(
-        'static void setup(${api.name}$nullTag api, {BinaryMessenger$nullTag binaryMessenger}) ');
+        'static void setup(${api.name}? api, {BinaryMessenger? binaryMessenger}) ');
     indent.scoped('{', '}', () {
       for (final Method func in api.methods) {
         indent.write('');
         indent.scoped('{', '}', () {
           indent.writeln(
-            'final BasicMessageChannel<Object$nullTag> channel = BasicMessageChannel<Object$nullTag>(',
+            'final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(',
           );
           final String channelName = channelNameFunc == null
               ? makeChannelName(api, func)
@@ -304,14 +291,14 @@
           indent.add(' else ');
           indent.scoped('{', '}', () {
             indent.write(
-              'channel.$messageHandlerSetter((Object$nullTag message) async ',
+              'channel.$messageHandlerSetter((Object? message) async ',
             );
             indent.scoped('{', '});', () {
               final String returnType =
-                  _addGenericTypesNullable(func.returnType, nullTag);
+                  _addGenericTypesNullable(func.returnType);
               final bool isAsync = func.isAsynchronous;
               final String emptyReturnStatement = isMockHandler
-                  ? 'return <Object$nullTag, Object$nullTag>{};'
+                  ? 'return <Object?, Object?>{};'
                   : func.returnType.isVoid
                       ? 'return;'
                       : 'return null;';
@@ -325,19 +312,18 @@
                 );
                 const String argsArray = 'args';
                 indent.writeln(
-                    'final List<Object$nullTag> $argsArray = (message as List<Object$nullTag>$nullTag)$unwrapOperator;');
+                    'final List<Object?> $argsArray = (message as List<Object?>?)!;');
                 String argNameFunc(int index, NamedType type) =>
                     _getSafeArgumentName(index, type);
                 enumerate(func.arguments, (int count, NamedType arg) {
-                  final String argType = _addGenericTypes(arg.type, nullTag);
+                  final String argType = _addGenericTypes(arg.type);
                   final String argName = argNameFunc(count, arg);
                   final String genericArgType =
-                      _makeGenericTypeArguments(arg.type, nullTag);
-                  final String castCall =
-                      _makeGenericCastCall(arg.type, nullTag);
+                      _makeGenericTypeArguments(arg.type);
+                  final String castCall = _makeGenericCastCall(arg.type);
 
                   indent.writeln(
-                      'final $argType$nullTag $argName = ($argsArray[$count] as $genericArgType$nullTag)${castCall.isEmpty ? '' : '$nullTag$castCall'};');
+                      'final $argType? $argName = ($argsArray[$count] as $genericArgType?)${castCall.isEmpty ? '' : '?$castCall'};');
                   if (!arg.type.isNullable) {
                     indent.writeln(
                         'assert($argName != null, \'Argument for $channelName was null, expected non-null $argType.\');');
@@ -346,7 +332,7 @@
                 final Iterable<String> argNames =
                     indexMap(func.arguments, (int index, NamedType field) {
                   final String name = _getSafeArgumentName(index, field);
-                  return '$name${field.type.isNullable ? '' : unwrapOperator}';
+                  return '$name${field.type.isNullable ? '' : '!'}';
                 });
                 call = 'api.${func.name}(${argNames.join(', ')})';
               }
@@ -365,7 +351,7 @@
                 }
                 const String returnExpression = 'output';
                 final String returnStatement = isMockHandler
-                    ? 'return <Object$nullTag, Object$nullTag>{\'${Keys.result}\': $returnExpression};'
+                    ? 'return <Object?, Object?>{\'${Keys.result}\': $returnExpression};'
                     : 'return $returnExpression;';
                 indent.writeln(returnStatement);
               }
@@ -379,42 +365,40 @@
 
 /// Converts a [List] of [TypeDeclaration]s to a comma separated [String] to be
 /// used in Dart code.
-String _flattenTypeArguments(List<TypeDeclaration> args, String nullTag) {
+String _flattenTypeArguments(List<TypeDeclaration> args) {
   return args
       .map<String>((TypeDeclaration arg) => arg.typeArguments.isEmpty
-          ? '${arg.baseName}$nullTag'
-          : '${arg.baseName}<${_flattenTypeArguments(arg.typeArguments, nullTag)}>$nullTag')
+          ? '${arg.baseName}?'
+          : '${arg.baseName}<${_flattenTypeArguments(arg.typeArguments)}>?')
       .join(', ');
 }
 
 /// Creates the type declaration for use in Dart code from a [NamedType] making sure
 /// that type arguments are used for primitive generic types.
-String _addGenericTypes(TypeDeclaration type, String nullTag) {
+String _addGenericTypes(TypeDeclaration type) {
   final List<TypeDeclaration> typeArguments = type.typeArguments;
   switch (type.baseName) {
     case 'List':
       return (typeArguments.isEmpty)
-          ? 'List<Object$nullTag>'
-          : 'List<${_flattenTypeArguments(typeArguments, nullTag)}>';
+          ? 'List<Object?>'
+          : 'List<${_flattenTypeArguments(typeArguments)}>';
     case 'Map':
       return (typeArguments.isEmpty)
-          ? 'Map<Object$nullTag, Object$nullTag>'
-          : 'Map<${_flattenTypeArguments(typeArguments, nullTag)}>';
+          ? 'Map<Object?, Object?>'
+          : 'Map<${_flattenTypeArguments(typeArguments)}>';
     default:
       return type.baseName;
   }
 }
 
-String _addGenericTypesNullable(TypeDeclaration type, String nullTag) {
-  final String genericdType = _addGenericTypes(type, nullTag);
-  return type.isNullable ? '$genericdType$nullTag' : genericdType;
+String _addGenericTypesNullable(TypeDeclaration type) {
+  final String genericdType = _addGenericTypes(type);
+  return type.isNullable ? '$genericdType?' : genericdType;
 }
 
 /// Generates Dart source code for the given AST represented by [root],
 /// outputting the code to [sink].
 void generateDart(DartOptions opt, Root root, StringSink sink) {
-  final String nullTag = opt.isNullSafe ? '?' : '';
-  final String unwrapOperator = opt.isNullSafe ? '!' : '';
   final List<String> customClassNames =
       root.classes.map((Class x) => x.name).toList();
   final List<String> customEnumNames =
@@ -430,7 +414,7 @@
     indent.writeln(
       '// ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis, prefer_null_aware_operators, omit_local_variable_types, unused_shown_name',
     );
-    indent.writeln('// @dart = ${opt.isNullSafe ? '2.12' : '2.8'}');
+    indent.writeln('// @dart = 2.12');
   }
 
   void writeEnums() {
@@ -471,17 +455,17 @@
       indent.write('Object encode() ');
       indent.scoped('{', '}', () {
         indent.writeln(
-          'final Map<Object$nullTag, Object$nullTag> pigeonMap = <Object$nullTag, Object$nullTag>{};',
+          'final Map<Object?, Object?> pigeonMap = <Object?, Object?>{};',
         );
         for (final NamedType field in klass.fields) {
           indent.write('pigeonMap[\'${field.name}\'] = ');
           if (customClassNames.contains(field.type.baseName)) {
             indent.addln(
-              '${field.name} == null ? null : ${field.name}$unwrapOperator.encode();',
+              '${field.name}?.encode();',
             );
           } else if (customEnumNames.contains(field.type.baseName)) {
             indent.addln(
-              '${field.name} == null ? null : ${field.name}$unwrapOperator.index;',
+              '${field.name}?.index;',
             );
           } else {
             indent.addln('${field.name};');
@@ -496,32 +480,29 @@
         if (customClassNames.contains(field.type.baseName)) {
           indent.format('''
 pigeonMap['${field.name}'] != null
-\t\t? ${field.type.baseName}.decode(pigeonMap['${field.name}']$unwrapOperator)
+\t\t? ${field.type.baseName}.decode(pigeonMap['${field.name}']!)
 \t\t: null''', leadingSpace: false, trailingNewline: false);
         } else if (customEnumNames.contains(field.type.baseName)) {
           indent.format('''
 pigeonMap['${field.name}'] != null
-\t\t? ${field.type.baseName}.values[pigeonMap['${field.name}']$unwrapOperator as int]
+\t\t? ${field.type.baseName}.values[pigeonMap['${field.name}']! as int]
 \t\t: null''', leadingSpace: false, trailingNewline: false);
         } else if (field.type.typeArguments.isNotEmpty) {
-          final String genericType =
-              _makeGenericTypeArguments(field.type, nullTag);
-          final String castCall = _makeGenericCastCall(field.type, nullTag);
-          final String castCallPrefix =
-              field.type.isNullable ? nullTag : unwrapOperator;
+          final String genericType = _makeGenericTypeArguments(field.type);
+          final String castCall = _makeGenericCastCall(field.type);
+          final String castCallPrefix = field.type.isNullable ? '?' : '!';
           indent.add(
-            '(pigeonMap[\'${field.name}\'] as $genericType$nullTag)$castCallPrefix$castCall',
+            '(pigeonMap[\'${field.name}\'] as $genericType?)$castCallPrefix$castCall',
           );
         } else {
-          final String genericdType =
-              _addGenericTypesNullable(field.type, nullTag);
+          final String genericdType = _addGenericTypesNullable(field.type);
           if (field.type.isNullable) {
             indent.add(
               'pigeonMap[\'${field.name}\'] as $genericdType',
             );
           } else {
             indent.add(
-              'pigeonMap[\'${field.name}\']$unwrapOperator as $genericdType',
+              'pigeonMap[\'${field.name}\']! as $genericdType',
             );
           }
         }
@@ -532,7 +513,7 @@
       );
       indent.scoped('{', '}', () {
         indent.writeln(
-          'final Map<Object$nullTag, Object$nullTag> pigeonMap = message as Map<Object$nullTag, Object$nullTag>;',
+          'final Map<Object?, Object?> pigeonMap = message as Map<Object?, Object?>;',
         );
         indent.write('return ${klass.name}');
         indent.scoped('(', ');', () {
@@ -551,7 +532,7 @@
       writeConstructor();
       indent.addln('');
       for (final NamedType field in klass.fields) {
-        final String datatype = _addGenericTypesNullable(field.type, nullTag);
+        final String datatype = _addGenericTypesNullable(field.type);
         indent.writeln('$datatype ${field.name};');
       }
       if (klass.fields.isNotEmpty) {
@@ -602,7 +583,7 @@
     '// ignore_for_file: public_member_api_docs, non_constant_identifier_names, avoid_as, unused_import, unnecessary_parenthesis',
   );
   indent.writeln('// ignore_for_file: avoid_relative_lib_imports');
-  indent.writeln('// @dart = ${opt.isNullSafe ? '2.12' : '2.8'}');
+  indent.writeln('// @dart = 2.12');
   indent.writeln('import \'dart:async\';');
   indent.writeln(
     'import \'dart:typed_data\' show Uint8List, Int32List, Int64List, Float64List;',
diff --git a/packages/pigeon/lib/generator_tools.dart b/packages/pigeon/lib/generator_tools.dart
index f32f202..5b9ac85 100644
--- a/packages/pigeon/lib/generator_tools.dart
+++ b/packages/pigeon/lib/generator_tools.dart
@@ -8,7 +8,7 @@
 import 'ast.dart';
 
 /// The current version of pigeon. This must match the version in pubspec.yaml.
-const String pigeonVersion = '2.0.4';
+const String pigeonVersion = '3.0.0';
 
 /// Read all the content from [stdin] to a String.
 String readStdin() {
diff --git a/packages/pigeon/lib/pigeon_lib.dart b/packages/pigeon/lib/pigeon_lib.dart
index 85144d9..0b5e75e 100644
--- a/packages/pigeon/lib/pigeon_lib.dart
+++ b/packages/pigeon/lib/pigeon_lib.dart
@@ -1041,9 +1041,6 @@
     ..addOption('java_out', help: 'Path to generated Java file (.java).')
     ..addOption('java_package',
         help: 'The package that generated Java code will be in.')
-    ..addFlag('dart_null_safety',
-        help: 'Makes generated Dart code have null safety annotations',
-        defaultsTo: true)
     ..addOption('objc_header_out',
         help: 'Path to generated Objective-C header file (.h).')
     ..addOption('objc_prefix',
@@ -1082,9 +1079,6 @@
       javaOptions: JavaOptions(
         package: results['java_package'],
       ),
-      dartOptions: DartOptions(
-        isNullSafe: results['dart_null_safety'],
-      ),
       copyrightHeader: results['copyright_header'],
       oneLanguage: results['one_language'],
       astOut: results['ast_out'],
diff --git a/packages/pigeon/pubspec.yaml b/packages/pigeon/pubspec.yaml
index 8f78999..b7911ae 100644
--- a/packages/pigeon/pubspec.yaml
+++ b/packages/pigeon/pubspec.yaml
@@ -2,7 +2,7 @@
 description: Code generator tool to make communication between Flutter and the host platform type-safe and easier.
 repository: https://github.com/flutter/packages/tree/main/packages/pigeon
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3Apigeon
-version: 2.0.4 # This must match the version in lib/generator_tools.dart
+version: 3.0.0 # This must match the version in lib/generator_tools.dart
 
 environment:
   sdk: ">=2.12.0 <3.0.0"
diff --git a/packages/pigeon/run_tests.sh b/packages/pigeon/run_tests.sh
index 5e311ea..be5cd99 100755
--- a/packages/pigeon/run_tests.sh
+++ b/packages/pigeon/run_tests.sh
@@ -86,38 +86,26 @@
 # test_null_safe_dart(<path to pigeon file>)
 #
 # Compiles the pigeon file to a temp directory and attempts to run the dart
-# analyzer on it with and without null safety turned on.
+# analyzer on it.
 test_pigeon_dart() {
   echo "test_pigeon_dart($1)"
-  temp_dir_1=$(mktmpdir)
-  temp_dir_2=$(mktmpdir)
+  temp_dir=$(mktmpdir)
 
   $run_pigeon \
     --input $1 \
-    --dart_out $temp_dir_1/pigeon.dart &
-  null_safe_gen_pid=$!
+    --dart_out $temp_dir/pigeon.dart &
+  gen_pid=$!
 
-  $run_pigeon \
-    --no-dart_null_safety \
-    --input $1 \
-    --dart_out $temp_dir_2/pigeon.dart &
-  non_null_safe_gen_pid=$!
-
-  wait $null_safe_gen_pid
-  wait $non_null_safe_gen_pid
+  wait $gen_pid
 
   # `./e2e_tests/test_objc/.packages` is used to get access to Flutter since
   # Pigeon doesn't depend on Flutter.
-  dartanalyzer $temp_dir_1/pigeon.dart --fatal-infos --fatal-warnings --packages ./e2e_tests/test_objc/.packages &
-  null_safe_analyze_pid=$!
-  dartanalyzer $temp_dir_2/pigeon.dart --fatal-infos --fatal-warnings --packages ./e2e_tests/test_objc/.packages &
-  non_null_safe_analyze_pid=$!
+  dart analyze $temp_dir/pigeon.dart --fatal-infos --fatal-warnings --packages ./e2e_tests/test_objc/.packages &
+  analyze_pid=$!
 
-  wait $null_safe_analyze_pid
-  wait $non_null_safe_analyze_pid
+  wait $analyze_pid
 
-  rm -rf $temp_dir_1
-  rm -rf $temp_dir_2
+  rm -rf $temp_dir
 }
 
 print_usage() {
@@ -184,7 +172,7 @@
 }
 
 run_dart_unittests() {
-  dart pub run pigeon:run_tests -t dart_unittests
+  dart run pigeon:run_tests -t dart_unittests
 }
 
 test_command_line() {
@@ -204,11 +192,11 @@
 }
 
 run_flutter_unittests() {
-  dart pub run pigeon:run_tests -t flutter_unittests
+  dart run pigeon:run_tests -t flutter_unittests
 }
 
 run_mock_handler_tests() {
-  dart pub run pigeon:run_tests -t mock_handler_tests
+  dart run pigeon:run_tests -t mock_handler_tests
 }
 
 run_dart_compilation_tests() {
diff --git a/packages/pigeon/test/dart_generator_test.dart b/packages/pigeon/test/dart_generator_test.dart
index 00c8158..4f03de6 100644
--- a/packages/pigeon/test/dart_generator_test.dart
+++ b/packages/pigeon/test/dart_generator_test.dart
@@ -27,10 +27,10 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Foobar'));
-    expect(code, contains('  dataType1 field1;'));
+    expect(code, contains('  dataType1? field1;'));
   });
 
   test('gen one enum', () {
@@ -47,7 +47,7 @@
       enums: <Enum>[anEnum],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('enum Foobar'));
     expect(code, contains('  one,'));
@@ -94,7 +94,7 @@
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Api'));
     expect(code, contains('Future<Output> doSomething(Input arg_input)'));
@@ -121,7 +121,7 @@
       ])
     ], classes: <Class>[], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Api'));
     expect(code, contains('Future<int> add(int arg_x, int arg_y)'));
@@ -149,7 +149,7 @@
       ])
     ], classes: <Class>[], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Api'));
     expect(code, contains('int add(int x, int y)'));
@@ -188,18 +188,18 @@
       )
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(
       code,
       contains(
-        'pigeonMap[\'nested\'] = nested == null ? null : nested.encode()',
+        'pigeonMap[\'nested\'] = nested?.encode()',
       ),
     );
     expect(
       code.replaceAll('\n', ' ').replaceAll('  ', ''),
       contains(
-        'nested: pigeonMap[\'nested\'] != null ? Input.decode(pigeonMap[\'nested\']) : null',
+        'nested: pigeonMap[\'nested\'] != null ? Input.decode(pigeonMap[\'nested\']!) : null',
       ),
     );
   });
@@ -244,7 +244,7 @@
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('abstract class Api'));
     expect(code, contains('static void setup(Api'));
@@ -281,7 +281,7 @@
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<void> doSomething'));
     expect(code, contains('return;'));
@@ -317,7 +317,7 @@
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     // The next line verifies that we're not setting a variable to the value of "doSomething", but
     // ignores the line where we assert the value of the argument isn't null, since on that line
@@ -349,7 +349,7 @@
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, matches('output.*=.*doSomething[(][)]'));
     expect(code, contains('Output doSomething();'));
@@ -394,59 +394,9 @@
       )
     ]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
-    expect(code,
-        contains('pigeonMap[\'enum1\'] = enum1 == null ? null : enum1.index;'));
-    expect(code, contains('? Enum.values[pigeonMap[\'enum1\'] as int]'));
-    expect(code, contains('EnumClass doSomething(EnumClass arg0);'));
-  });
-
-  test('flutter enum argument with enum class nullsafe', () {
-    final Root root = Root(apis: <Api>[
-      Api(name: 'Api', location: ApiLocation.flutter, methods: <Method>[
-        Method(
-          name: 'doSomething',
-          arguments: <NamedType>[
-            NamedType(
-                type: const TypeDeclaration(
-                  baseName: 'EnumClass',
-                  isNullable: false,
-                ),
-                name: '',
-                offset: null)
-          ],
-          returnType:
-              const TypeDeclaration(baseName: 'EnumClass', isNullable: false),
-          isAsynchronous: false,
-        )
-      ])
-    ], classes: <Class>[
-      Class(name: 'EnumClass', fields: <NamedType>[
-        NamedType(
-            type: const TypeDeclaration(
-              baseName: 'Enum',
-              isNullable: true,
-            ),
-            name: 'enum1',
-            offset: null)
-      ]),
-    ], enums: <Enum>[
-      Enum(
-        name: 'Enum',
-        members: <String>[
-          'one',
-          'two',
-        ],
-      )
-    ]);
-    final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
-    final String code = sink.toString();
-    expect(
-        code,
-        contains(
-            'pigeonMap[\'enum1\'] = enum1 == null ? null : enum1!.index;'));
+    expect(code, contains('pigeonMap[\'enum1\'] = enum1?.index;'));
     expect(code, contains('? Enum.values[pigeonMap[\'enum1\']! as int]'));
     expect(code, contains('EnumClass doSomething(EnumClass arg0);'));
   });
@@ -474,7 +424,7 @@
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, matches('channel.send[(]null[)]'));
   });
@@ -538,7 +488,7 @@
     ], enums: <Enum>[]);
     final StringBuffer mainCodeSink = StringBuffer();
     final StringBuffer testCodeSink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, mainCodeSink);
+    generateDart(const DartOptions(), root, mainCodeSink);
     final String mainCode = mainCodeSink.toString();
     expect(mainCode, isNot(contains('import \'fo\\\'o.dart\';')));
     expect(mainCode, contains('class Api {'));
@@ -546,39 +496,14 @@
     expect(mainCode, isNot(contains('.ApiMock.doSomething')));
     expect(mainCode, isNot(contains('\'${Keys.result}\': output')));
     expect(mainCode, isNot(contains('return <Object, Object>{};')));
-    generateTestDart(
-        const DartOptions(isNullSafe: false), root, testCodeSink, "fo'o.dart");
+    generateTestDart(const DartOptions(), root, testCodeSink, "fo'o.dart");
     final String testCode = testCodeSink.toString();
     expect(testCode, contains('import \'fo\\\'o.dart\';'));
     expect(testCode, isNot(contains('class Api {')));
     expect(testCode, contains('abstract class ApiMock'));
     expect(testCode, isNot(contains('.ApiMock.doSomething')));
     expect(testCode, contains('\'${Keys.result}\': output'));
-    expect(testCode, contains('return <Object, Object>{};'));
-  });
-
-  test('opt out of nndb', () {
-    final Class klass = Class(
-      name: 'Foobar',
-      fields: <NamedType>[
-        NamedType(
-            type: const TypeDeclaration(
-              baseName: 'dataType1',
-              isNullable: true,
-            ),
-            name: 'field1',
-            offset: null),
-      ],
-    );
-    final Root root = Root(
-      apis: <Api>[],
-      classes: <Class>[klass],
-      enums: <Enum>[],
-    );
-    final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
-    final String code = sink.toString();
-    expect(code, contains('// @dart = 2.8'));
+    expect(testCode, contains('return <Object?, Object?>{};'));
   });
 
   test('gen one async Flutter Api', () {
@@ -621,12 +546,12 @@
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('abstract class Api'));
     expect(code, contains('Future<Output> doSomething(Input arg0);'));
     expect(
-        code, contains('final Output output = await api.doSomething(arg0);'));
+        code, contains('final Output output = await api.doSomething(arg0!);'));
   });
 
   test('gen one async Flutter Api with void return', () {
@@ -668,7 +593,7 @@
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, isNot(matches('=.s*doSomething')));
     expect(code, contains('await api.doSomething('));
@@ -715,7 +640,7 @@
       ])
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Api'));
     expect(code, matches('Output.*doSomething.*Input'));
@@ -744,7 +669,7 @@
       ]),
     ], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: false), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, matches('channel.send[(]null[)]'));
   });
@@ -757,8 +682,7 @@
     final Root root = Root(apis: <Api>[], classes: <Class>[], enums: <Enum>[]);
     final StringBuffer sink = StringBuffer();
     generateDart(
-      DartOptions(
-          isNullSafe: false, copyrightHeader: _makeIterable('hello world')),
+      DartOptions(copyrightHeader: _makeIterable('hello world')),
       root,
       sink,
     );
@@ -787,7 +711,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Foobar'));
     expect(code, contains('  List<int?>? field1;'));
@@ -815,7 +739,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('class Foobar'));
     expect(code, contains('  Map<String?, int?>? field1;'));
@@ -845,7 +769,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('doit(List<int?> arg'));
   });
@@ -874,7 +798,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('doit(List<int?> arg'));
   });
@@ -898,7 +822,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<List<int?>> doit('));
     expect(
@@ -936,7 +860,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('List<int?> doit('));
     expect(
@@ -963,7 +887,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<int?> doit()'));
     expect(code, contains('return (replyMap[\'result\'] as int?);'));
@@ -987,7 +911,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<int?> doit()'));
     expect(code, contains('return (replyMap[\'result\'] as int?);'));
@@ -1010,7 +934,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('int? doit();'));
     expect(code, contains('final int? output = api.doit();'));
@@ -1034,7 +958,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<int?> doit();'));
     expect(code, contains('final int? output = await api.doit();'));
@@ -1057,7 +981,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(
         code,
@@ -1086,7 +1010,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('Future<void> doit(int? arg_foo) async {'));
   });
@@ -1112,7 +1036,7 @@
       enums: <Enum>[],
     );
     final StringBuffer sink = StringBuffer();
-    generateDart(const DartOptions(isNullSafe: true), root, sink);
+    generateDart(const DartOptions(), root, sink);
     final String code = sink.toString();
     expect(code, contains('void doit(int? foo);'));
   });
diff --git a/packages/pigeon/test/pigeon_lib_test.dart b/packages/pigeon/test/pigeon_lib_test.dart
index 6d6447c..d40c015 100644
--- a/packages/pigeon/test/pigeon_lib_test.dart
+++ b/packages/pigeon/test/pigeon_lib_test.dart
@@ -329,12 +329,6 @@
     expect(classNames.contains('OnlyVisibleFromNesting'), true);
   });
 
-  test('null safety flag', () {
-    final PigeonOptions results =
-        Pigeon.parseArgs(<String>['--dart_null_safety']);
-    expect(results.dartOptions?.isNullSafe, isTrue);
-  });
-
   test('copyright flag', () {
     final PigeonOptions results =
         Pigeon.parseArgs(<String>['--copyright_header', 'foobar.txt']);
@@ -423,7 +417,7 @@
 @HostApi()
 abstract class NotificationsHostApi {
   void doit(Foo foo);
-}  
+}
 ''';
     final ParseResults results = _parseSource(code);
     expect(results.errors.length, 0);
@@ -462,7 +456,7 @@
   test('test field initialization', () {
     const String code = '''
 class Foo {
-  int? x = 123;  
+  int? x = 123;
 }
 
 @HostApi()