jqwik: ClassCastException when using Combinators during shrinking

Testing Problem

ClassCastException when using Combinators and arbitraries producing elements of the type hierarchy.

java.lang.ClassCastException: class mypackage.MyTypeLike$Any cannot be cast to class mypackage.MyTypeLike (mypackage.MyTypeLike$Any and mypackage.MyTypeLike are in unnamed module of loader 'app')
	at net.jqwik.engine.properties.arbitraries.combinations.DefaultCombinator5.lambda$combineFunction$0(DefaultCombinator5.java:33)
	at net.jqwik.engine.properties.shrinking.CombinedShrinkable.createValue(CombinedShrinkable.java:25)
	at net.jqwik.engine.properties.shrinking.CombinedShrinkable.value(CombinedShrinkable.java:21)
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
	at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682)
	at net.jqwik.engine.properties.shrinking.AbstractSampleShrinker.lambda$shrink$2(AbstractSampleShrinker.java:52)

Suggested Solution

Very brief analysis points to the lack of variance in functional combinator methods. i.e.:

<R> Arbitrary<R> flatAs(F5<T1, T2, T3, T4, T5, Arbitrary<@NotNull R>> flatCombinator)

<R> Arbitrary<R> as(Combinators.F5<T1, T2, T3, T4, T5, R> combinator)

Combinators.Combinator5<T1, T2, T3, T4, T5> filter(Combinators.F5<T1, T2, T3, T4, T5, Boolean> filter)

<R> Function<List<Object>, R> combineFunction(Combinators.F5<T1, T2, T3, T4, T5, R> combinator)

should probably be relaxed to:

<R> Arbitrary<R> flatAs(F5<? super T1, ? super T2, ? super T3, ? super T4, ? super T5, Arbitrary<? extends R>> flatCombinator)

<R> Arbitrary<R> as(Combinators.F5<? super T1, ? super T2, ? super T3, ? super T4, ? super T5, ? extends R> combinator)

Combinators.Combinator5<T1, T2, T3, T4, T5> filter(Combinators.F5<? super T1, ? super T2, ? super T3, ? super T4, ? super T5, Boolean> filter)

<R> Function<List<Object>, R> combineFunction(Combinators.F5<? super T1, ? super T2, ? super T3, ? super T4, ? super T5, ? extends R> combinator)