Re: Warnings about keymaps

[Glenn Morris]

Stefan Monnier wrote:

> It could, but it shouldn't complain about assignment to a constant,
> since the defvar will not perform any assignment.  I.e. maybe a warning
> is OK, but not the warning we currently get.

How about this? Or perhaps the defvar should just be silently
optimized away, like the default-boundp test seems to be trying to do.

*** bytecomp.el 10 Sep 2009 06:22:30 -0000 2.258
--- bytecomp.el 14 Sep 2009 23:30:56 -0000
***************
*** 4025,4032 ****
                (let ((tmp (make-symbol "defconst-tmp-var")))
                  `(funcall '(lambda (,tmp) (defconst ,var ,tmp))
                            ,value))
              ;; `defvar' sets `var' only when unbound.
!             `(if (not (default-boundp ',var)) (setq-default ,var ,value))))
        (when (eq fun 'defconst)
          ;; This will signal an appropriate error at runtime.
          `(eval ',form)))
--- 4036,4046 ----
                (let ((tmp (make-symbol "defconst-tmp-var")))
                  `(funcall '(lambda (,tmp) (defconst ,var ,tmp))
                            ,value))
+             (if (memq var byte-compile-const-variables)
+                 (byte-compile-warn "attempt to defvar constant `%s' \
+ has no effect" var)
                ;; `defvar' sets `var' only when unbound.
!               `(if (not (default-boundp ',var)) (setq-default ,var ,value)))))
        (when (eq fun 'defconst)
          ;; This will signal an appropriate error at runtime.
          `(eval ',form)))