This appears to be similar to
GROOVY-9881, but it's specifically in the method-overload procedure. Given a functional value type with two method overloads:
When this code is invoked from static code, the STC errors out on an ambiguous method reference even if the method type isn't:
I think this may have something to do with the relaxed SAM matching that is used to bridge ambiguous closure syntax, but when a plain method reference is used, there's no ambiguity available.