plai:1:9 disallows murec define-types

[anonymous]

In earlier versions (tested with 1:6), this program evaluates without error:

#lang planet plai/plai:1:9

(define-type A

[mta]
[a (b B?)])

(define-type B

[mtb]
[b (a A?)])

Changing 1:6 into 1:9 installs the new version, whereupon the program signals this error:

reference to an identifier before its definition: B?

[plai]

This is now fixed.