This works:
(js (macrolet ((foo (bar &rest body) `(+ ,@body))) (foo 1 2 3 4)))
This doesn't:
(js (macrolet ((foo (bar &body body) `(+ ,@body))) (foo 1 2 3 4)))
Related to this, make ParenScript macrolet support all lambda list keywords that Lisp macrolet supports.