* lisp/emacs-lisp/byte-run.el (defsubst): Do not native compile
defsubsts to have them always effective.
'(nil byte-compile-inline-expand))
(error "`%s' is a primitive" name))
`(prog1
- (defun ,name ,arglist ,@body)
+ (defun ,name ,arglist
+ ;; Never native-compile defsubsts as we need the byte
+ ;; definition in `byte-compile-unfold-bcf' to perform the
+ ;; inlining (Bug#42664).
+ (declare (speed -1))
+ ,@body)
(eval-and-compile
(put ',name 'byte-optimizer 'byte-compile-inline-expand))))