diff options
Diffstat (limited to 'lisp/emacs-lisp/gv.el')
| -rw-r--r-- | lisp/emacs-lisp/gv.el | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/lisp/emacs-lisp/gv.el b/lisp/emacs-lisp/gv.el index 5d6e6e1b372..fae3bcb86f6 100644 --- a/lisp/emacs-lisp/gv.el +++ b/lisp/emacs-lisp/gv.el @@ -493,9 +493,20 @@ This is like the `&' operator of the C language. Note: this only works reliably with lexical binding mode, except for very simple PLACEs such as (function-symbol 'foo) which will also work in dynamic binding mode." - (gv-letplace (getter setter) place - `(cons (lambda () ,getter) - (lambda (gv--val) ,(funcall setter 'gv--val))))) + (let ((code + (gv-letplace (getter setter) place + `(cons (lambda () ,getter) + (lambda (gv--val) ,(funcall setter 'gv--val)))))) + (if (or lexical-binding + ;; If `code' still starts with `cons' then presumably gv-letplace + ;; did not add any new let-bindings, so the `lambda's don't capture + ;; any new variables. As a consequence, the code probably works in + ;; dynamic binding mode as well. + (eq (car-safe code) 'cons)) + code + (macroexp--warn-and-return + "Use of gv-ref probably requires lexical-binding" + code)))) (defsubst gv-deref (ref) "Dereference REF, returning the referenced value. |