[Sbcl-devel] Some more style-warnings from fopcompile would be nice....

[Douglas K. <do...@go...>]

COMPILE-FILE on the following example correctly signals a style-warning
about a call to the structure constructor but only because of  the
gratuitous/silly (in this case) 'incf' of unused variable X.  Absent that -
and/or anything else that would foil the fopcompiler - such that the form
becomes fopcompilable, no warning is emitted about the incorrect call.

Which of the following seems the least slippery slope to go down to fix
this?

1. Concoct some arguments acceptable to 'valid-fun-use' (i.e. synthesize a
COMBINATION and LVARS of type *universal-type*) so that the fopcompiler can
call valid-fun-use. This seems hard to get right because
*compiler-error-context* would be lying, etc, etc.

2. Factor out the argument count checks into a separate function that can
do something reasonable for the fopcompiler, and
2a. have the fopcompiler signal the warning
2a. have fopcompilable-p return nil so that it is forced to go through the
proper mechanism

(defstruct (foo (:constructor make-foo (slot))) slot)

(defvar *foo*)

(let ((x 0)) (incf x) (setq *foo* (make-foo)))