On Fri, Aug 10, 2012 at 12:33 PM, Neil Toronto <[email protected]> wrote: > Using typed `flatten' takes too much manual instantiation. In the following > program, the first three uses fail to typecheck; the last passes.
This looks like a bug ... > I think the problem is that TR only unfolds the type of (Treeof A) once. If > I manually unfold it once; i.e., I change it to this: > > (define-type (Treeof A) (U A (Listof (Rec T (U A (Listof T)))))) > > then the program passes, because TR now unfolds it twice. But this diagnosis is not right. Recursive types in TR are equal to their unfoldings; there should never be a need to explicitly unfold more than once, either in the typechecker or manually. I'll look into what's going on here. -- sam th [email protected] _________________________ Racket Developers list: http://lists.racket-lang.org/dev
