feat: add common properties with different nullability to base mixin

packages/freezed/lib/src/freezed_generator.dart

@@ -147,6 +147,8 @@ class FreezedGenerator extends ParserGenerator<GlobalData, Data, Freezed> {
           isPossiblyDartCollection: commonParameter.isPossiblyDartCollection,
           // TODO: support hasJsonKey
           hasJsonKey: false,
+          isCommonWithDifferentNullability:
+              commonParameter.isCommonWithDifferentNullability,
         ),
     ];
   }
@@ -252,27 +254,50 @@ Read here: https://github.com/rrousselGit/freezed/blob/master/packages/freezed/C
   ) {
     return constructorsNeedsGeneration.first.parameters.allParameters
         .map((parameter) {
-          var hasAnyFinalProperty = false;
+          var anyMatchingPropertyIsFinal = false;
+          var anyMatchingPropertyIsNullable = false;
+
           for (final constructor in constructorsNeedsGeneration) {
             final matchingParameter =
                 constructor.parameters.allParameters.firstWhereOrNull((p) {
-              return p.name == parameter.name && p.type == parameter.type;
+              return p.name == parameter.name &&
+                  _typeStringWithoutNullability(p.type) ==
+                      _typeStringWithoutNullability(parameter.type);
             });
 
             if (matchingParameter == null) return null;
-            if (matchingParameter.isFinal) hasAnyFinalProperty = true;
+            if (matchingParameter.isFinal) anyMatchingPropertyIsFinal = true;
+            if (matchingParameter.isNullable)
+              anyMatchingPropertyIsNullable = true;
           }
 
-          if (hasAnyFinalProperty) {
-            return parameter.copyWith(isFinal: true);
+          final isNullable =
+              parameter.isNullable || anyMatchingPropertyIsNullable;
+
+          if (parameter.isNullable != isNullable) {
+            print(parameter.name);
           }
 
-          return parameter;
+          return parameter.copyWith(
+            isFinal: parameter.isFinal || anyMatchingPropertyIsFinal,
+            isNullable: isNullable,
+            type: isNullable && (parameter.type?.endsWith('?') == false)
+                ? '${parameter.type}?'
+                : parameter.type,
+            isCommonWithDifferentNullability:
+                parameter.isNullable != isNullable,
+          );
         })
         .whereNotNull()
         .toList();
   }
 
+  String? _typeStringWithoutNullability(String? type) {
+    return type?.endsWith('?') == true
+        ? type?.substring(0, type.length - 1)
+        : type;
+  }
+
   Future<List<ConstructorDetails>> _parseConstructorsNeedsGeneration(
     BuildStep buildStep,
     ClassElement element,
@@ -606,7 +631,9 @@ Read here: https://github.com/rrousselGit/freezed/blob/master/packages/freezed/C
             ).toList(),
             genericsDefinition: data.genericsDefinitionTemplate,
             genericsParameter: data.genericsParameterTemplate,
-            allProperties: commonProperties,
+            allProperties: commonProperties
+                .whereNot((element) => element.isCommonWithDifferentNullability)
+                .toList(),
             data: data,
           );
 

packages/freezed/lib/src/templates/concrete_template.dart

@@ -135,6 +135,7 @@ ${copyWith?.abstractCopyWithGetter ?? ''}
         doc: '',
         isPossiblyDartCollection: false,
         showDefaultValue: false,
+        isCommonWithDifferentNullability: false,
       );
 
       parameters = ParametersTemplate(

packages/freezed/lib/src/templates/copy_with.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart';
 import 'package:freezed/src/templates/parameter_template.dart';
 import 'package:freezed/src/templates/properties.dart';
 
@@ -65,23 +66,28 @@ ${_abstractDeepCopyMethods().join()}
       final body = _copyWithMethodBody(
         parametersTemplate: ParametersTemplate(
           const [],
-          namedParameters: commonProperties.map((e) {
-            return Parameter(
-              decorators: e.decorators,
-              name: e.name,
-              isNullable: false,
-              isFinal: false,
-              isDartList: false,
-              isDartMap: false,
-              isDartSet: false,
-              showDefaultValue: false,
-              isRequired: false,
-              defaultValueSource: '',
-              type: e.type,
-              doc: e.doc,
-              isPossiblyDartCollection: e.isPossiblyDartCollection,
-            );
-          }).toList(),
+          namedParameters: commonProperties
+              .map((e) {
+                return Parameter(
+                  decorators: e.decorators,
+                  name: e.name,
+                  isNullable: false,
+                  isFinal: false,
+                  isDartList: false,
+                  isDartMap: false,
+                  isDartSet: false,
+                  showDefaultValue: false,
+                  isRequired: false,
+                  defaultValueSource: '',
+                  type: e.type,
+                  doc: e.doc,
+                  isPossiblyDartCollection: e.isPossiblyDartCollection,
+                  isCommonWithDifferentNullability:
+                      e.isCommonWithDifferentNullability,
+                );
+              })
+              .whereNot((element) => element.isCommonWithDifferentNullability)
+              .toList(),
         ),
         returnType: '_value.copyWith',
       );

packages/freezed/lib/src/templates/parameter_template.dart

@@ -82,6 +82,7 @@ class ParametersTemplate {
         doc: await documentationOfParameter(e, buildStep),
         isPossiblyDartCollection: e.type.isPossiblyDartCollection,
         showDefaultValue: true,
+        isCommonWithDifferentNullability: false,
       );
 
       if (isAssignedToThis) return LocalParameter.fromParameter(value);
@@ -184,6 +185,7 @@ class Parameter {
     required this.isFinal,
     required this.isPossiblyDartCollection,
     required this.showDefaultValue,
+    required this.isCommonWithDifferentNullability,
   });
 
   Parameter.fromParameter(Parameter p)
@@ -201,6 +203,7 @@ class Parameter {
           showDefaultValue: p.showDefaultValue,
           doc: p.doc,
           isPossiblyDartCollection: p.isPossiblyDartCollection,
+          isCommonWithDifferentNullability: p.isCommonWithDifferentNullability,
         );
 
   final String? type;
@@ -216,6 +219,7 @@ class Parameter {
   final bool isPossiblyDartCollection;
   final bool isFinal;
   final String doc;
+  final bool isCommonWithDifferentNullability;
 
   Parameter copyWith({
     String? type,
@@ -232,6 +236,7 @@ class Parameter {
     bool? isDartMap,
     bool? isDartSet,
     bool? isFinal,
+    bool? isCommonWithDifferentNullability,
   }) =>
       Parameter(
         type: type ?? this.type,
@@ -248,6 +253,8 @@ class Parameter {
         isFinal: isFinal ?? this.isFinal,
         isPossiblyDartCollection:
             isPossiblyDartCollection ?? this.isPossiblyDartCollection,
+        isCommonWithDifferentNullability: isCommonWithDifferentNullability ??
+            this.isCommonWithDifferentNullability,
       );
 
   @override
@@ -283,6 +290,7 @@ class LocalParameter extends Parameter {
     required List<String> decorators,
     required String doc,
     required bool isPossiblyDartCollection,
+    required bool isCommonWithDifferentNullability,
   }) : super(
           name: name,
           type: type,
@@ -297,6 +305,7 @@ class LocalParameter extends Parameter {
           defaultValueSource: defaultValueSource,
           doc: doc,
           isPossiblyDartCollection: isPossiblyDartCollection,
+          isCommonWithDifferentNullability: isCommonWithDifferentNullability,
         );
 
   LocalParameter.fromParameter(Parameter p)
@@ -313,6 +322,7 @@ class LocalParameter extends Parameter {
           decorators: p.decorators,
           doc: p.doc,
           isPossiblyDartCollection: p.isPossiblyDartCollection,
+          isCommonWithDifferentNullability: p.isCommonWithDifferentNullability,
         );
 
   @override
@@ -346,6 +356,7 @@ class CallbackParameter extends Parameter {
     required this.parameters,
     required String doc,
     required bool isPossiblyDartCollection,
+    required bool isCommonWithDifferentNullability,
   }) : super(
           name: name,
           type: type,
@@ -360,6 +371,7 @@ class CallbackParameter extends Parameter {
           defaultValueSource: defaultValueSource,
           doc: doc,
           isPossiblyDartCollection: isPossiblyDartCollection,
+          isCommonWithDifferentNullability: isCommonWithDifferentNullability,
         );
 
   final ParametersTemplate parameters;

packages/freezed/lib/src/templates/properties.dart

@@ -31,6 +31,7 @@ class Property {
     required this.isDartMap,
     required this.isDartSet,
     required this.isPossiblyDartCollection,
+    required this.isCommonWithDifferentNullability,
   }) : type = type ?? 'dynamic';
 
   static Future<Property> fromParameter(
@@ -60,6 +61,7 @@ class Property {
       defaultValueSource: defaultValue,
       hasJsonKey: element.hasJsonKey,
       isPossiblyDartCollection: element.type.isPossiblyDartCollection,
+      isCommonWithDifferentNullability: false,
     );
   }
 
@@ -75,6 +77,7 @@ class Property {
   final bool hasJsonKey;
   final String doc;
   final bool isPossiblyDartCollection;
+  final bool isCommonWithDifferentNullability;
 
   @override
   String toString() {
@@ -135,6 +138,7 @@ class Property {
     bool? hasJsonKey,
     String? doc,
     bool? isPossiblyDartCollection,
+    bool? isCommonWithDifferentNullability,
   }) {
     return Property(
       type: type ?? this.type,
@@ -150,6 +154,8 @@ class Property {
       isDartSet: isDartSet ?? this.isDartSet,
       isPossiblyDartCollection:
           isPossiblyDartCollection ?? this.isPossiblyDartCollection,
+      isCommonWithDifferentNullability: isCommonWithDifferentNullability ??
+          this.isCommonWithDifferentNullability,
     );
   }
 }

packages/freezed/lib/src/templates/prototypes.dart

@@ -127,6 +127,7 @@ String _mapPrototype(
           // TODO: do we want to support freezed classes that implements MapView/ListView?
           isPossiblyDartCollection: false,
           showDefaultValue: false,
+          isCommonWithDifferentNullability: false,
         ),
       ]);
     },
@@ -191,6 +192,7 @@ String _unionPrototype(
       defaultValueSource: '',
       doc: '',
       isPossiblyDartCollection: false,
+      isCommonWithDifferentNullability: false,
     );
 
     if (constructor.isDefault) {

packages/freezed/pubspec.yaml

@@ -6,10 +6,10 @@ version: 2.1.0+1
 homepage: https://github.com/rrousselGit/freezed
 
 environment:
-  sdk: '>=2.17.0 <3.0.0'
+  sdk: ">=2.17.0 <3.0.0"
 
 dependencies:
-  analyzer: ">=4.2.0 <5.0.0"
+  analyzer: ">=4.6.0 <5.0.0"
   build: ^2.0.0
   build_config: ^1.0.0
   collection: ^1.15.0

packages/freezed/test/integration/multiple_constructors.dart

@@ -64,6 +64,14 @@ class SharedParam with _$SharedParam {
   const factory SharedParam.named(String a, int c) = SharedParam1;
 }
 
+@freezed
+class SharedParamNullable with _$SharedParamNullable {
+  const factory SharedParamNullable(String a, String b, int c) =
+      SharedParamNullable0;
+  const factory SharedParamNullable.named(String? a, String b, int d) = 
+      SharedParamNullable1;
+}
+
 @freezed
 class Complex with _$Complex {
   @Assert("a != ''", '"Hello"')

packages/freezed/test/multiple_constructors_test.dart

@@ -504,8 +504,48 @@ void main() {
 }
 '''), throwsCompileError);
     });
+  });
+
+  group('SharedParamNullable', () {
+    test('has the common properties available', () {
+      SharedParamNullable value = SharedParamNullable('a', 'b', 42);
+      expect(value.a, 'a');
+
+      value = SharedParamNullable.named('b', 'c', 24);
+      expect(value.a, 'b');
+    });
+
+    test(
+      "copy doesn't have shared params with different nullability",
+      () async {
+        await expectLater(compile(r'''
+import 'multiple_constructors.dart';
+
+void main() {
+  final param = SharedParamNullable('a', 'b', 42);
+  param.copyWith(a: '2');
+}
+'''), throwsCompileError);
+
+        await expectLater(compile(r'''
+import 'multiple_constructors.dart';
+
+void main() {
+  final param = SharedParamNullable('a', 'b', 42);
+  param.copyWith(b: '1');
+}
+'''), completes);
 
-    // TODO: shared property name but different type
+        await expectLater(compile(r'''
+import 'multiple_constructors.dart';
+
+void main() {
+  final param = SharedParamNullable('a', 'b', 42);
+  param.copyWith(c: 42);
+}
+'''), throwsCompileError);
+      },
+    );
   });
 
   test('Can have a named constructor and a property using the same name', () {