diff options
Diffstat (limited to 'lisp/emacs-lisp/bytecomp.el')
| -rw-r--r-- | lisp/emacs-lisp/bytecomp.el | 39 |
1 files changed, 31 insertions, 8 deletions
diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el index a122e81ba3c..4a10ae29804 100644 --- a/lisp/emacs-lisp/bytecomp.el +++ b/lisp/emacs-lisp/bytecomp.el @@ -317,7 +317,9 @@ Elements of the list may be: lexical-dynamic lexically bound variable declared dynamic elsewhere make-local calls to `make-variable-buffer-local' that may be incorrect. - mapcar mapcar called for effect. + ignored-return-value + function called without using the return value where this + is likely to be a mistake not-unused warning about using variables with symbol names starting with _. constants let-binding of, or assignment to, constants/nonvariables. docstrings docstrings that are too wide (longer than @@ -330,7 +332,7 @@ Elements of the list may be: empty-body body argument to a special form or macro is empty. If the list begins with `not', then the remaining elements specify warnings to -suppress. For example, (not mapcar) will suppress warnings about mapcar. +suppress. For example, (not free-vars) will suppress the `free-vars' warning. The t value means \"all non experimental warning types\", and excludes the types in `byte-compile--emacs-build-warning-types'. @@ -3490,6 +3492,27 @@ lambda-expression." (byte-compile-report-error (format-message "`%s' defined after use in %S (missing `require' of a library file?)" (car form) form))) + + (when byte-compile--for-effect + (let ((sef (function-get (car form) 'side-effect-free))) + (cond + ((and sef (or (eq sef 'error-free) + byte-compile-delete-errors)) + ;; This transform is normally done in the Lisp optimiser, + ;; so maybe we don't need to bother about it here? + (setq form (cons 'progn (cdr form))) + (setq handler #'byte-compile-progn)) + ((and (or sef (eq (car form) 'mapcar)) + (byte-compile-warning-enabled-p + 'ignored-return-value (car form))) + (byte-compile-warn-x + (car form) + "value from call to `%s' is unused%s" + (car form) + (cond ((eq (car form) 'mapcar) + "; use `mapc' or `dolist' instead") + (t ""))))))) + (if (and handler ;; Make sure that function exists. (and (functionp handler) @@ -3523,11 +3546,7 @@ lambda-expression." (byte-compile-callargs-warn form)) (if byte-compile-generate-call-tree (byte-compile-annotate-call-tree form)) - (when (and byte-compile--for-effect (eq (car form) 'mapcar) - (byte-compile-warning-enabled-p 'mapcar 'mapcar)) - (byte-compile-warn-x - (car form) - "`mapcar' called for effect; use `mapc' or `dolist' instead")) + (byte-compile-push-constant (car form)) (mapc 'byte-compile-form (cdr form)) ; wasteful, but faster. (byte-compile-out 'byte-call (length (cdr form)))) @@ -4367,7 +4386,11 @@ This function is never called when `lexical-binding' is nil." (defun byte-compile-ignore (form) (dolist (arg (cdr form)) - (byte-compile-form arg t)) + ;; Compile args for value (to avoid warnings about unused values), + ;; emit a discard after each, and trust the LAP peephole optimiser + ;; to annihilate useless ops. + (byte-compile-form arg) + (byte-compile-discard)) (byte-compile-form nil)) ;; Return the list of items in CONDITION-PARAM that match PRED-LIST. |