Some users have difficulty understanding the error that occurs when declarations are encountered in contexts where they aren't allowed

[fare]

Dan Weinreb 2009-01-05 13:49:46 EST

(defun foo (a)
  (declare (fixnum a))
  (+ a a))

works fine.

(defmacro bad () '(declare (fixnum a)))
(defun foo (a) (bad) (+ a a))

gets a compile-time error, because macros are not allowed to expand into declarations.

However, the text of the error message is:

DECLARE not expected in (DECLARE (FIXNUM A)).

That's pretty unclear.

[NB: was ITA bug 52936]

[gb]

(In [15314]) Warn (via full warning) on duplicate bindings in SYMBOL-MACROLET, MACROLET, FLET, LABELS (fixes ticket:927.)

If a DECLARE expression is encountered when a form is expected, make the error message more verbose (and mention macroexpansion as a possible cause of the problem.) Fixes ticket:926.

Warn (via a full warning) if a local function shadows a global CL function name. Fixes ticket:923.

If STYLE-WARNINGs are incidentally signaled during (e.g.) macroexpansion and are handled and postprocessed by the compiler, ensure that the warning actually generated will be a STYLE-WARNING.