test/Foo.di(3,1): Error: class test.Foo.FooPrivate is forward
referenced when looking for 'opAssign'
forward reference in Foo.di
test/Bar.d(14,25): Error: cannot implicitly convert expression
(p) of type test.BarPrivate.BarPrivate to test.Foo.FooPrivate
I'm unable to cast from BarPrivate to FooPrivate because it can't
recognize Bar : Foo; inheritance from Foo.di (FooPrivate.d and
BarPrivate.d is ignored).
test/Foo.di(3,1): Error: class test.Foo.FooPrivate is forward
referenced when looking for 'opCast'
same as first
