Analyzer crash: type '_ConstructorNameWithInvalidTypeArgs' is not a subtype of type 'ConstructorNameImpl?' in type cast

[jensjoha]

I have this weird script, t.dart:

import "t.dart" as a;

enum MyEnum implements Bar<({a.B<int, (int c,)> e, Foo f})> {
  a;

  get field => throw "no";
}

class Bar<E> {
  final E field;
  Bar(this.field);
}

class B<E, F> {}

class Foo {}

Analyzing it is fine:

$ out/ReleaseX64/dart-sdk/bin/dart analyze t.dart
Analyzing t.dart...
No issues found!

If I then remove a comma:

import "t.dart" as a;

enum MyEnum implements Bar<({a.B<int, (int c)> e, Foo f})> {
  a;

  get field => throw "no";
}

class Bar<E> {
  final E field;
  Bar(this.field);
}

class B<E, F> {}

class Foo {}

it crashes:

$ out/ReleaseX64/dart-sdk/bin/dart analyze t.dart
Analyzing t.dart...
An unexpected error was encountered by the Analysis Server.
Please file an issue at https://github.com/dart-lang/sdk/issues/new/choose with the following details:

Internal error: type '_ConstructorNameWithInvalidTypeArgs' is not a subtype of type 'ConstructorNameImpl?' in type cast
#0      LegacyAnalysisServer.sendServerErrorNotification (package:analysis_server/src/legacy_analysis_server.dart:742:31)
#1      ErrorNotifier.logException (package:analysis_server/src/server/error_notifier.dart:45:12)
#2      MulticastInstrumentationService.logException (package:analyzer/instrumentation/multicast_service.dart:28:15)
#3      Driver._captureExceptions.errorFunction (package:analysis_server/src/server/driver.dart:557:15)
#4      _Zone._processUncaughtError (dart:async/zone.dart:1178:14)
#5      _CustomZone.handleUncaughtError (dart:async/zone.dart:1399:5)
#6      Future._propagateToListeners (dart:async/future_impl.dart:832:24)
#7      Future._completeError (dart:async/future_impl.dart:730:5)
<asynchronous suspension>

Unhandled exception:
type '_ConstructorNameWithInvalidTypeArgs' is not a subtype of type 'ConstructorNameImpl?' in type cast
#0      AstBuilder.handleEnumElement (package:analyzer/src/fasta/ast_builder.dart:4091:32)
#1      Parser.parseEnumElement (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2665:14)
#2      Parser.parseEnum (package:_fe_analyzer_shared/src/parser/parser_impl.dart:2422:17)
#3      Parser.parseTopLevelKeywordDeclaration (package:_fe_analyzer_shared/src/parser/parser_impl.dart:687:14)
#4      Parser.parseTopLevelDeclarationImpl (package:_fe_analyzer_shared/src/parser/parser_impl.dart:533:14)
#5      Parser.parseUnit (package:_fe_analyzer_shared/src/parser/parser_impl.dart:411:15)
#6      Parser.parseCompilationUnit2 (package:analyzer/src/generated/parser.dart:100:32)
#7      Parser.parseCompilationUnit (package:analyzer/src/generated/parser.dart:96:12)
#8      FileState.parseCode.<anonymous closure> (package:analyzer/src/dart/analysis/file_state.dart:697:25)
#9      OperationPerformanceImpl.run (package:analyzer/src/util/performance/operation_performance.dart:155:23)
#10     FileState.parseCode (package:analyzer/src/dart/analysis/file_state.dart:671:24)
#11     FileState.getParsed (package:analyzer/src/dart/analysis/file_state.dart:628:16)
#12     FileState._getUnlinkedUnit (package:analyzer/src/dart/analysis/file_state.dart:905:16)
#13     FileState.refresh.<anonymous closure> (package:analyzer/src/dart/analysis/file_state.dart:746:29)
#14     OperationPerformanceImpl.run (package:analyzer/src/util/performance/operation_performance.dart:155:23)
#15     FileState.refresh (package:analyzer/src/dart/analysis/file_state.dart:745:17)
#16     FileSystemState._newFile.<anonymous closure> (package:analyzer/src/dart/analysis/file_state.dart:1709:12)
#17     OperationPerformanceImpl.run (package:analyzer/src/util/performance/operation_performance.dart:155:23)
#18     FileSystemState._newFile (package:analyzer/src/dart/analysis/file_state.dart:1708:17)
#19     FileSystemState.getFileForPath (package:analyzer/src/dart/analysis/file_state.dart:1502:14)
#20     AnalysisDriver._discoverLibraries (package:analyzer/src/dart/analysis/driver.dart:1671:16)
#21     AnalysisDriver.performWork (package:analyzer/src/dart/analysis/driver.dart:1188:5)
#22     AnalysisDriverScheduler._run (package:analyzer/src/dart/analysis/driver.dart:2431:24)
<asynchronous suspension>
Bad state: The analysis server crashed unexpectedly

[dart-github-bot]

Summary: The Dart analyzer crashes when parsing a complex enum declaration. Removing a comma in the type arguments triggers a type cast error.

[bwilkerson]

@scheglov