Invalid generated code when using Default instances

[mrverdant13]

Bug description

Hey there 👋🏼 !

I found an interesting bug when using freezed for classes with members with default values.

If I create a const instance of a default annotation, the generated code is not valid.

Reproduction setup

Given the following code snippet:

const defaultFalse = Default(false);

@freezed
class MyClass with _$MyClass {
  const factory MyClass({
    @defaultFalse bool myBool,
  }) = _MyClass;
}

After running code generation, part of the generated code includes this output:

class _$_MyClass implements _MyClass {
  const _$_MyClass({this.myBool = als}); // <========= 👀 

  /// ... more generated code ....
}

Expected output

-const _$_MyClass({this.myBool = als});
+const _$_MyClass({this.myBool = false});