Flutter : 3.7.0, Dart : 2.9

While running the dart migrate tool to migrate to null-safety got this error.

type 'Null' is not a subtype of type 'GenericFunctionTypeElement' in type cast at offset 857 in .../lib/app_specific_utils/_core/app_cloud_provider.dart (DioError)

0 EdgeBuilder.visitNamedType (package:nnbd_migration/src/edge_builder.dart:1488:36)

1 NamedTypeImpl.accept (package:analyzer/src/dart/ast/ast.dart:9003:50)

2 EdgeBuilder._dispatch (package:nnbd_migration/src/edge_builder.dart:2375:24)

3 EdgeBuilder.visitCatchClause (package:nnbd_migration/src/edge_builder.dart:666:5)

4 CatchClauseImpl.accept (package:analyzer/src/dart/ast/ast.dart:1708:50)

5 EdgeBuilder._dispatch (package:nnbd_migration/src/edge_builder.dart:2375:24)

6 EdgeBuilder._dispatchList (package:nnbd_migration/src/edge_builder.dart:2393:7)

7 EdgeBuilder.visitTryStatement (package:nnbd_migration/src/edge_builder.dart:2001:7)

8 TryStatementImpl.accept (package:analyzer/src/dart/ast/ast.dart:12926:50)

9 EdgeBuilder._dispatch (package:nnbd_migration/src/edge_builder.dart:2375:24)

10 EdgeBuilder.visitNode (package:nnbd_migration/src/edge_builder.dart:1567:9)

11 GeneralizingAstVisitor.visitStatement (package:analyzer/dart/ast/visitor.dart:649:40)

12 GeneralizingAstVisitor.visitBlock (package:analyzer/dart/ast/visitor.dart:170:32)

13 BlockImpl.accept (package:analyzer/src/dart/ast/ast.dart:1260:50)

14 EdgeBuilder._dispatch (package:nnbd_migration/src/edge_builder.dart:2375:24)

15 EdgeBuilder.visitNode (package:nnbd_migration/src/edge_builder.dart:1567:9)

16 GeneralizingAstVisitor.visitFunctionBody (package:analyzer/dart/ast/visitor.dart:362:46)

17 GeneralizingAstVisitor.visitBlockFunctionBody (package:analyzer/dart/ast/visitor.dart:173:56)

18 BlockFunctionBodyImpl.accept (package:analyzer/src/dart/ast/ast.dart:1207:50)

19 EdgeBuilder._dispatch (package:nnbd_migration/src/edge_builder.dart:2375:24)

20 EdgeBuilder._handleExecutableDeclaration (package:nnbd_migration/src/edge_builder.dart:2682:7)

21 EdgeBuilder.visitMethodDeclaration (package:nnbd_migration/src/edge_builder.dart:1393:5)

22 MethodDeclarationImpl.accept (package:analyzer/src/dart/ast/ast.dart:8533:50)

23 EdgeBuilder._dispatch (package:nnbd_migration/src/edge_builder.dart:2375:24)

24 EdgeBuilder._dispatchList (package:nnbd_migration/src/edge_builder.dart:2393:7)

25 EdgeBuilder.visitClassOrMixinOrExtensionDeclaration (package:nnbd_migration/src/edge_builder.dart:717:7)

26 EdgeBuilder.visitClassDeclaration (package:nnbd_migration/src/edge_builder.dart:676:5)

27 ClassDeclarationImpl.accept (package:analyzer/src/dart/ast/ast.dart:2000:50)

28 EdgeBuilder._dispatch (package:nnbd_migration/src/edge_builder.dart:2375:24)

29 EdgeBuilder.visitNode (package:nnbd_migration/src/edge_builder.dart:1567:9)

30 GeneralizingAstVisitor.visitCompilationUnit (package:analyzer/dart/ast/visitor.dart:216:52)

31 CompletenessTracker.visitCompilationUnit. (package:nnbd_migration/src/utilities/completeness_tracker.dart:52:24)

32 PermissiveModeVisitor.reportExceptionsIfPermissive (package:nnbd_migration/src/utilities/permissive_mode.dart:26:24)

33 CompletenessTracker.visitCompilationUnit (package:nnbd_migration/src/utilities/completeness_tracker.dart:43:5)

34 CompilationUnitImpl.accept (package:analyzer/src/dart/ast/ast.dart:2501:50)

35 NullabilityMigrationImpl.processInput (package:nnbd_migration/src/nullability_migration_impl.dart:224:12)

36 NonNullableFix.processUnit (package:nnbd_migration/src/front_end/non_nullable_fix.dart:162:16)

37 _FixCodeProcessor.runLaterPhases. (package:nnbd_migration/migration_cli.dart:1088:19)

38 _FixCodeProcessor.processResources (package:nnbd_migration/migration_cli.dart:1020:26)

#39 _FixCodeProcessor.runLaterPhases (package:nnbd_migration/migration_cli.dart:1086:5) #40 MigrationCliRunner.run (package:nnbd_migration/migration_cli.dart:695:24) #41 MigrateCommand.run (package:dartdev/src/commands/migrate.dart:37:7) #42 CommandRunner.runCommand (package:args/command_runner.dart:212:13) #43 DartdevRunner.runCommand (package:dartdev/dartdev.dart:241:18) #44 runDartdev (package:dartdev/dartdev.dart:65:18) #45 main (file:///opt/s/w/ir/x/w/sdk/pkg/dartdev/bin/dartdev.dart:11:3) ======================================================================== The file at the path is abstract class AppCloudProvider extends BaseApiProvider { var path = ""; Dio _apiClient; AppCloudProvider(this.path, this._apiClient); @override Future> delete(T item) async { try { var response = await _apiClient.delete("$path/${item.uniqueId}"); return AppResponse(data: response.data); } on DioError catch (e) { return ApiHelper.processErrorInDioServerResponse(e); } } @override Future> update(T item) async { try { var data = toMap(item); var response = await apiClient.post(updatePath(), data: data); try { Map data = response.data; if (data[AppColumn.code] == 1) { return AppResponse(data: item); } else { return AppResponse( data: null, error: ErrorResponse.fromResponse(response)); } } catch (e) { return ApiHelper.processErrorInParsing(e); } } on DioError catch (e) { print(e.message); return ApiHelper.processErrorInDioServerResponse(e); } } String updatePath() => path; @override Future> add(T item) async { return update(item); // try { // var response = // await _apiClient.post("$path/${item.uniqueId}", data: toMap(item)); // return AppResponse(data: response.data); // } on DioError catch (e) { // return ApiHelper.processErrorInDioServerResponse(e); // } } @override Future addItems(List items) => throw Exception("not implemented"); @override Future updateItems(List items)=> throw Exception("not implemented"); @override Future> fetch(String id) async { try { var response = await _apiClient.get(updateFetchPath(id)); try { Map data = response.data; if (data[AppColumn.code] == 1) { return AppResponse(data: fromMap(data["Data"])); } else { return AppResponse( data: null, error: ErrorResponse.fromResponse(response)); } } catch (e) { return ApiHelper.processErrorInParsing(e); } } on DioError catch (e) { print(e.message); return ApiHelper.processErrorInDioServerResponse(e); } } @override Future>> fetchItems( {List orderBy, int limitBy, int startFrom, List where, bool isClearOldItems = false, Map options}) async { // print("$this --fetching items"); /// saving query info too for next time fetch from local db var secondaryInfo = Map(); if (where != null) { where.forEach((item) => secondaryInfo[item.key] = (item.value is String) ? item.value : "${item.value}"); } if (startFrom != null) secondaryInfo["page"] = "$startFrom"; try { Uri uri = Uri(path: path, queryParameters: secondaryInfo); var response = await _apiClient.getUri(uri); try { if (response.data[AppColumn.code] != 5) { if (response.data != null && response.data[AppColumn.data] != null) { var items = processItemsFromResponse( response.data[AppColumn.data], secondaryInfo); return AppResponse.fromData(AppListManager( items, limitBy, //added check when the data field directly contains a list instead of nested object (response.data[AppColumn.data] is List)?1:response.data[AppColumn.data]["page"], (response.data[AppColumn.data] is List)?99:response.data[AppColumn.data]["total_pages"])); } else { return AppResponse( data: null, error: ErrorResponse.fromResponse(response)); } } else { return AppResponse( data: null, error: ErrorResponse.error("Your Account is Deactivated")); } } catch (e) { return ApiHelper.processErrorInParsing(e); } } on DioError catch (e) { return ApiHelper.processErrorInDioServerResponse(e); } } @override Map toMap(T item) { return item.toMap(); } /// override this method if response doesn't contains direct list of items List processItemsFromResponse(data, Map secondaryInfo) { List items = (data as List).map((record) { var item = fromMap(record); return item; }).toList(); return items; } Dio get apiClient => _apiClient; String updateFetchPath(String id) { return "$path/$id"; } }

dart-lang / sdk

type 'Null' is not a subtype of type 'GenericFunctionTypeElement' in type cast at offset <number> #53330