Macros: Augmenting a constructor doesn't copy over the default values.

[rrousselGit]

Hello!

Consider the following code:

@override
FutureOr<void> buildDefinitionForClass(ClassDeclaration clazz, TypeDefinitionBuilder builder) async{
  final constructor = await builder.constructorsOf(clazz);

  final builder2 = await builder.buildConstructor(constructor.first.identifier);

  builder2.augment();
}

Then, given:

@Macro()
class DataClass {
  DataClass({this.b = 42});
...
}

This will generate:

augment class DataClass {
  augment DataClass({prefix0.int b, });
}

This generated code will fail, because the augmented constructor lacks a default value.

[lrhn]

That looks like correctly generated augmentations. The augmentation itself should inherit the default value from the declaration it augments (an augmenting function or constructor cannot declare a new default value, only the original declaration can declare the default values, as currently specified).

If the code doesn't work, then it's the augmentation implementation that doesn't do what it should.

[rrousselGit]

Interesting. Because at the moment, the augmenting constructor can define default values just fine.

We can generate augment DataClass(int a, {int b = 42}) and have no error.
In fact it seems like the augmentation can specify a default value that's different from the original, and that works too.