Hindley-Milner in common lisp
https://bitbucket.org/tarballs_are_good/lisp-random/src/50b56958f3ea/HindleyMilner
In my environment( SBCL 1.0.29.1 ), the test code (test.lisp) does not give correct result
(try (cdr '(1 2 3))) ;; :: (LIST NUM) ;;;;; but actual result :: (LIST T2)