When using DEFMETHOD we called EVAL-WITH-ENV using :load-toplevel mode instead of :execute. This causes some trouble. Until the bytecodes compiler is revised we may safely fall back to :execute.

src/clos/method.lsp

@@ -168,7 +168,7 @@
         ;; explicitely the bytecodes compiler with an environment, no
         ;; stepping, compiler-env-p = t and execute = nil, so that the
         ;; form does not get executed.
-        (si::eval-with-env method-lambda env nil t nil)))
+        (si::eval-with-env method-lambda env nil t t)))
     (values call-next-method-p
 	    next-method-p-p
 	    in-closure-p)))