(setf fdefinition) and (setf symbol-function) don't clear derived type-information

[Nikodemus Siivola]

Related to bug 659173.

  (let ((*evaluator-mode* :compile)
        (*derive-function-types* t))
    (eval `(progn
             (defun clear-derived-types-on-set-fdefn-1 ()
               "foo")
             (setf (symbol-function 'clear-derived-types-on-set-fdefn-1)
                   (constantly "foobar"))
             (defun clear-derived-types-on-set-fdefn-2 ()
               (length (clear-derived-types-on-set-fdefn-1)))))
    (clear-derived-types-on-set-fdefn-2)) ; => 3, should be 6

[Nikodemus Siivola (nikodemus)]

In 1.0.43.49.