Why kotlin interface cannot use lambda, when same interface in java can use?

I have two interfaces, one is IA, write by java, another is IB, which write by kotlin.

now, I have a class C, which have two properties.

I use those two interface, why C().ib cannot use lambda?

This is a known issue: https://youtrack.jetbrains.com/oauth?state=%2Fissue%2FKT-7770 Please vote for it if you think the issue should be fixed…