6342eb96c0
In this commit we add nullability to upper type of a substituted constraint in the situation like (Stub<_L> <: SomeType), where _L is fixed to nullable Stub<_L>?. We have to change this constraint to L <: SomeType? and not to L <: SomeType as before, otherwise nullability become broken (direct substitution of Stub<_L> to L is illegal here). #KT-50470 Fixed