为什么这是SBCL中的错误？你如何调用传递给你的函数的lambda？
* (defun call-foo (foo) (foo))
; in: DEFUN CALL-FOO
; (SB-INT:NAMED-LAMBDA CALL-FOO
; (FOO)
; (BLOCK CALL-FOO (FOO)))
;
; caught STYLE-WARNING:
; The variable FOO is defined but never used.
; in: DEFUN CALL-FOO
; (FOO)
;
; caught STYLE-WARNING:
; undefined function: FOO
;
; compilation unit finished
; Undefined function:
; FOO
; caught 2 STYLE-WARNING conditions
CALL-FOO