Consider the following:

void meth(@DelegatesTo(type="java.util.Map.Entry")) {
}
meth { key }

The expression "key" is shown as unknown (underlined) because the static inner class "Entry" cannot be resolved correctly by the type inference engine.

Note: This case is required to work when a private static inner class is the delegate type. "value=Outer.Inner.class" will produce a compile error for not-visible inner class.