Cryptic warnings, or no warnings for skipped declarations

[Robert P. Goldman]

There are a couple of cases in PROCESS-IGNORE-DECL that can either emit
a STYLE-WARNING that's a little cryptic, or ignore a declaration without
emitting anything. Here's a proposed patch that fixes this.

Originally posted to sbcl-devel and available as http://thread.gmane.org/gmane.lisp.steel-bank.devel/15513

Last tested on 1.0.45.4 on Mac OS X, but this is not a bug, it's "portable," and occurs on all platforms.

[Robert P. Goldman (rpgoldman)]

I'm actually not sure that this patch is enough. I don't understand exactly the ramifications, but with the COND in its current ordering, a non-local special variable that is declared as ignored gets a warning as an ignored undefined variable rather than an ignored special. I'm not sure that's right, but didn't want to change it.

Here's an example:

(in-package :common-lisp-user)

(defvar specialvar)

(defun warning-goofs ()
  (declare (ignore specialvar undeclared))
  nil)

[Nikodemus Siivola (nikodemus)]

The style-warning for symbol-macros is not a good addition: SBCL doesn't currently signal style-warnings for unused symbol macros at all, so skipping the IGNORE declaration does exactly what the user asked for.

I'll merge something along the lines of you patch shortly.

Thanks for looking into this!

[Nikodemus Siivola (nikodemus)]

In 1.0.46.17.