Super calls to default interface methods are incorrectly transformed

[LlamaLad7]

In an example like the following:

@Mixin(BeeEntity.class)
public abstract class ExampleMixin implements IAngerable {
    @Override
    public void writeAngerNBT(CompoundNBT nbt) {
        System.out.println("Test!");
        IAngerable.super.writeAngerNBT(nbt);
    }
}

The super call to the default method in IAngerable looks like this: INVOKESPECIAL net/minecraft/entity/IAngerable.writeAngerNBT (Lnet/minecraft/nbt/CompoundNBT;)V (itf) However, after the mixin is applied, this becomes: INVOKESPECIAL net/minecraft/entity/passive/BeeEntity.writeAngerNBT (Lnet/minecraft/nbt/CompoundNBT;)V (itf) which has different behaviour.

This was reproduced with stock Mixin 0.8.3 and Java 8.

[Kroppeb]

Interesting the link constant remains a InterfaceMethodRef resulting in the jvm failing to load the class (on fabric at least)

[2No2Name]

Confirmed with sponge-mixin-0.11.4+mixin.0.8.5.jar

[zml2008]

We do not produce Fabric's fork of Mixin -- the only reproductions that add information are those on stock Mixin.

[Kroppeb]

Seems like the issue might be here: MixinTargetContext.java#L570-L576

It doesn't check whether the "methodRef" is on a class or on an interface

[LlamaLad7]

Simply changing this line to use getOwner instead of getImplementor fixes the issue and doesn't seem to break anything else. https://github.com/SpongePowered/Mixin/blob/155314e6e91465dad727e621a569906a410cd6f4/src/main/java/org/spongepowered/asm/mixin/transformer/MixinTargetContext.java#L872 Not sure why getImplementor was introduced in the first place, this is its only usage.

[LlamaLad7]

It's also worth noting that this issue only occurs if there is a detached superclass, so if anyone is actually running into it they can most likely avoid it by simply extending the target's superclass.