Type alias is not passed to freezed

[jonasfranz]

Describe the bug
If you have two classes with the same name but different packages (e.g. Timer from dart:async and a custom class) freezed will use just one of those classes for both types resulting in a compile time error.

To Reproduce

Create a class that has a conflicting name:

class Timer { }

Create a freezed class that uses both conflicting classes:

import 'dart:async' as async;

import 'package:example/timer.dart';
import 'package:freezed_annotation/freezed_annotation.dart';

part 'timer_state.freezed.dart';

typedef AsyncTimer = async.Timer;

@freezed
class TimerState with _$TimerState {
  const TimerState._();
  const factory TimerState({
    @Default({}) Map<Timer, async.Timer> timerNotifications,
  }) = _TimerState;
}

Run the freezed generator.

Expected behavior

I would expect that the corresponding freezed part class uses the same aliased class name (async.Timer). But it uses the un-aliased class name resulting in a compile time error since the constructor signatures don't match.

Part of the generated code:

/// @nodoc
mixin _$TimerState {
  Map<Timer, Timer> get timerNotifications =>
      throw _privateConstructorUsedError;

  @JsonKey(ignore: true)
  $TimerStateCopyWith<TimerState> get copyWith =>
      throw _privateConstructorUsedError;
}

[jonasfranz]

Might be an duplicate of #628

[rrousselGit]

Closing in favor of #628