diff options
| -rw-r--r-- | lisp/emacs-lisp/cl-macs.el | 11 | ||||
| -rw-r--r-- | test/lisp/emacs-lisp/cl-macs-tests.el | 19 |
2 files changed, 26 insertions, 4 deletions
diff --git a/lisp/emacs-lisp/cl-macs.el b/lisp/emacs-lisp/cl-macs.el index f78fdcf0085..9e93e8775d5 100644 --- a/lisp/emacs-lisp/cl-macs.el +++ b/lisp/emacs-lisp/cl-macs.el @@ -2139,9 +2139,14 @@ Like `cl-flet' but the definitions can refer to previous ones. ;; setq the fresh new `ofargs' vars instead ;-) (let ((shadowings (mapcar (lambda (b) (if (consp b) (car b) b)) bindings))) - ;; If `var' is shadowed, then it clearly can't be - ;; tail-called any more. - (not (memq var shadowings))))) + (and + ;; If `var' is shadowed, then it clearly can't be + ;; tail-called any more. + (not (memq var shadowings)) + ;; If any of the new bindings is a dynamic + ;; variable, the body is not in tail position. + (not (cl-some #'macroexp--dynamic-variable-p + shadowings)))))) `(,(car exp) ,bindings . ,(funcall opt-exps exps))) ((and `(condition-case ,err-var ,bodyform . ,handlers) (guard (not (eq err-var var)))) diff --git a/test/lisp/emacs-lisp/cl-macs-tests.el b/test/lisp/emacs-lisp/cl-macs-tests.el index 13da60ec45e..ced2cc10f30 100644 --- a/test/lisp/emacs-lisp/cl-macs-tests.el +++ b/test/lisp/emacs-lisp/cl-macs-tests.el @@ -666,7 +666,24 @@ collection clause." (should (pcase (macroexpand '(cl-labels ((len (xs n) (if xs (len (cdr xs) (1+ n)) n))) #'len)) - (`(function (lambda (,_ ,_) . ,_)) t)))) + (`(function (lambda (,_ ,_) . ,_)) t))) + + ;; Verify that there is no tail position inside dynamic variable bindings. + (defvar dyn-var) + (let ((dyn-var 'a)) + (cl-labels ((f (x) (if x + dyn-var + (let ((dyn-var 'b)) + (f dyn-var))))) + (should (equal (f nil) 'b)))) + + ;; Control: same as above but with lexical binding. + (let ((lex-var 'a)) + (cl-labels ((f (x) (if x + lex-var + (let ((lex-var 'b)) + (f lex-var))))) + (should (equal (f nil) 'a))))) (ert-deftest cl-macs--progv () (defvar cl-macs--test) |