plt/racket — pull request #705 by shekari (2014-07-02 15:24:32+00:00)
Title: Add test for mu and invariant recursive calls.

This case used to generate a substitution and now doesn't. I believe this is the correct behavior because the substitution generated before (b2 = Symbol) does not correctly unify with the first item because of the unfolding inside the vector.

Can someone doublecheck my reasoning?