json macro throws when there is a colliding member

[mit-mit]

Repro:

@JsonCodable()
class Vehicle {
  final int wheels;
  final String description;
  Vehicle(this.wheels, this.description);
  Vehicle.fromJson(Map m) : this(2, 'foo');
}

Expected result: Just the error "Cannot generate a fromJson constructor due to this existing one."

Actual result: That error + a throw:

Invalid argument(s): [typeParameters.length: 2][typeArguments.length: 0][element: abstract interface class Map<K, V>][typeParameters: [K, V]][typeArguments: []] #0      new InterfaceTypeImpl (package:analyzer/src/dart/element/type.dart:487:7)
#1      InterfaceElementImpl.instantiate (package:analyzer/src/dart/element/element.dart:3709:18)
#2      DeclarationBuilder._resolveTypeCodeNamed (package:analyzer/src/summary2/macro_declarations.dart:519:24)
#3      DeclarationBuilder.resolveType (package:analyzer/src/summary2/macro_declarations.dart:321:16)
#4      _DeclarationPhaseIntrospector.resolve (package:analyzer/src/summary2/macro_application.dart:1130:35)
#5      new ExternalMacroExecutorBase.<anonymous closure>.<anonymous closure>.<anonymous closure> (package:_macros/src/executor/executor_base.dart:89:22)
#6      _rootRun (dart:async/zone.dart:1399:13)
#7      _CustomZone.run (dart:async/zone.dart:1301:19)
#8      withRemoteInstanceZone (package:_macros/src/executor/remote_instance.dart:172:15)
#9      new ExternalMacroExecutorBase.<anonymous closure>.<anonymous closure> (package:_macros/src/executor/executor_base.dart:45:9)
#10     _rootRunUnary (dart:async/zone.dart:1415:13)
#11     _CustomZone.runUnary (dart:async/zone.dart:1308:19)
#12     _CustomZone.runUnaryGuarded (dart:async/zone.dart:1217:7)
#13     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:365:11)
#14     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:297:7)
#15     _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:784:19)
#16     _StreamController._add (dart:async/stream_controller.dart:658:7)
#17     _StreamController.add (dart:async/stream_controller.dart:606:5)
#18     _SingleIsolatedMacroExecutor.start.<anonymous closure> (package:_macros/src/executor/isolated_executor.dart:64:33)
#19     _rootRunUnary (dart:async/zone.dart:1415:13)
#20     _CustomZone.runUnary (dart:async/zone.dart:1308:19)
#21     _CustomZone.runUnaryGuarded (dart:async/zone.dart:1217:7)
#22     _BufferingStreamSubscription._sendData (dart:async/stream_impl.dart:365:11)
#23     _BufferingStreamSubscription._add (dart:async/stream_impl.dart:297:7)
#24     _SyncStreamControllerDispatch._sendData (dart:async/stream_controller.dart:784:19)
#25     _StreamController._add (dart:async/stream_controller.dart:658:7)
#26     _StreamController.add (dart:async/stream_controller.dart:606:5)
#27     _RawReceivePort._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)

[bwilkerson]

Any progress?

[jakemac53]

Sorry, didn't realize I was assigned here. I am pretty sure this is an analyzer error due to the missing type arguments on Map.

[jakemac53]

Specifically, the macro is asking to resolve the type Map. Currently the analyzer will throw if you ask to resolve a type which has type parameters, but no explicit type arguments. And by resolve, I mean calling the resolve API on the DeclarationPhaseIntrospector implementation, which converts it to a "StaticType" - this roughly translates to an "InterfaceType" in the analyzer, which is what it tries to create. But that requires explicit type arguments, so something needs to add those in.