Allow suppressing the "lexical arg shadows dynbound var" warning

In most cases the right way to fix this warning is by renaming
the offending argument, but in some cases this is inconvenient, as is
the case in `cl-defstruct` where arg names are imposed by slot names.

This patch also happens to fix a few bugs along the way:
- miscompilation of (lambda (gcs-done) (lambda (x) (+ x gcs-done)))
- errors about void function `byte-compile-warn-x` if the warning was
  emitted via `cconv-fv` when bytecomp was not loaded.
Oh, and it improves the warning by making the location info slightly
more precise.

* lisp/emacs-lisp/cconv.el (cconv--analyze-function): Remove this warning.
* lisp/emacs-lisp/bytecomp.el (byte-compile-check-lambda-list):
Warn about it here instead.  Let `with-suppressed-warnings` control it
under `lexical`.

diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index 64a579480179f7563fc8c5c27e03f7a12abd0b12..659d698b603f67fa0d95f9d09d09ae62ed1596f6 100644 (file)
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -3082,6 +3082,14 @@ If FORM is a lambda or a macro, byte-compile it as a function."
               (byte-compile-warn-x
                 arg "repeated variable %s in lambda-list" arg))
              (t
+              (when (and lexical-binding
+                         (cconv--not-lexical-var-p
+                          arg byte-compile-bound-variables)
+                         (byte-compile-warning-enabled-p 'lexical arg))
+                (byte-compile-warn-x
+                 arg
+                 "Lexical argument shadows the dynamic variable %S"
+                 arg))
               (push arg vars))))
       (setq list (cdr list)))))
 

diff --git a/lisp/emacs-lisp/cconv.el b/lisp/emacs-lisp/cconv.el
index 601e2c13d6152a406dec9ac037e19227ef2913a4..3e75020a0135d9dbf00fe4112f2a4d4bbc21af66 100644 (file)
--- a/lisp/emacs-lisp/cconv.el
+++ b/lisp/emacs-lisp/cconv.el
@@ -682,11 +682,6 @@ FORM is the parent form that binds this var."
     (when lexical-binding
       (dolist (arg args)
         (cond
-         ((cconv--not-lexical-var-p arg cconv--dynbound-variables)
-          (byte-compile-warn-x
-           arg
-           "Lexical argument shadows the dynamic variable %S"
-           arg))
          ((eq ?& (aref (symbol-name arg) 0)) nil) ;Ignore &rest, &optional, ...
          (t (let ((varstruct (list arg nil nil nil nil)))
               (cl-pushnew arg byte-compile-lexical-variables)