Use setf slot-value everywhere.

helm-files.el

@@ -3032,13 +3032,12 @@ Don't use it in your own code unless you know what you are doing.")
    (persistent-action :initform 'helm-ff-kill-or-find-buffer-fname)))
 
 (defmethod helm--setup-source :after ((source helm-recentf-source))
-  (set-slot-value
-   source 'action
-   (append (symbol-value (helm-actions-from-type-file))
-           '(("Delete file(s) from recentf" .
-              (lambda (_candidate)
-                (cl-loop for file in (helm-marked-candidates)
-                         do (setq recentf-list (delq file recentf-list)))))))))
+  (setf (slot-value source 'action)
+        (append (symbol-value (helm-actions-from-type-file))
+                '(("Delete file(s) from recentf" .
+                   (lambda (_candidate)
+                     (cl-loop for file in (helm-marked-candidates)
+                              do (setq recentf-list (delq file recentf-list)))))))))
 
 (defvar helm-source-recentf nil 
   "See (info \"(emacs)File Conveniences\").

helm-org.el

@@ -133,10 +133,10 @@ Note this have no effect in `helm-org-in-buffer-headings'."
 
 (defmethod helm--setup-source :after ((source helm-org-headings-class))
   (let ((parents (slot-value source 'parents)))
-    (set-slot-value source 'candidate-transformer
-                    (lambda (candidates)
-                      (let ((cands (helm-org-get-candidates candidates parents)))
-                        (if parents (nreverse cands) cands))))))
+    (setf (slot-value source 'candidate-transformer)
+          (lambda (candidates)
+            (let ((cands (helm-org-get-candidates candidates parents)))
+              (if parents (nreverse cands) cands))))))
 
 (defun helm-source-org-headings-for-files (filenames &optional parents)
   (helm-make-source "Org Headings" 'helm-org-headings-class

helm-source.el

@@ -759,14 +759,14 @@ Argument CLASS is an eieio class object.
 Arguments ARGS are keyword value pairs as defined in CLASS."
   (declare (indent 2))
   (let ((source (apply #'make-instance class name args)))
-    (set-slot-value source 'name name)
+    (setf (slot-value source 'name) name)
     (helm--setup-source source)
     (helm-setup-user-source source)
     (helm--create-source source)))
 
 (defun helm-make-type (class &rest args)
   (let ((source (apply #'make-instance class args)))
-    (set-slot-value source 'name nil)
+    (setf (slot-value source 'name) nil)
     (helm--setup-source source)
     (helm--create-source source)))
 
@@ -819,14 +819,12 @@ an eieio class."
                                  actions (quote ,new-action) ,index))
                                (t actions)))))
     (if (functionp actions)
-        (set-slot-value source 'action (list (cons "Default action" actions)))
-        (set-slot-value source 'action (helm-interpret-value actions source)))
+        (setf (slot-value source 'action) (list (cons "Default action" actions)))
+        (setf (slot-value source 'action) (helm-interpret-value actions source)))
     (when (or (symbolp action-transformers) (functionp action-transformers))
       (setq action-transformers (list action-transformers)))
-    (set-slot-value
-     source
-     'action-transformer
-     (delq nil (append (list transformer) action-transformers)))))
+    (setf (slot-value source 'action-transformer)
+          (delq nil (append (list transformer) action-transformers)))))
 
 
 ;;; Methods to build sources.
@@ -875,74 +873,75 @@ an eieio class."
     (warn "Deprecated usage of helm `delayed' slot in `%s'"
           (slot-value source 'name)))
   (helm-aif (slot-value source 'keymap)
-      (and (symbolp it) (set-slot-value source 'keymap (symbol-value it))))
+      (and (symbolp it) (setf (slot-value source 'keymap) (symbol-value it))))
   (helm-aif (slot-value source 'persistent-help)
-      (set-slot-value source 'header-line
-                      (helm-source--persistent-help-string it source))
-    (set-slot-value source 'header-line (helm-source--header-line source)))
+      (setf (slot-value source 'header-line)
+            (helm-source--persistent-help-string it source))
+    (setf (slot-value source 'header-line) (helm-source--header-line source)))
   (helm-aif (slot-value source 'candidate-number-limit)
-      (and (symbolp it) (set-slot-value
-                         source 'candidate-number-limit (symbol-value it))))
+      (and (symbolp it) (setf (slot-value source 'candidate-number-limit)
+                              (symbol-value it))))
   (when (and (slot-value source 'fuzzy-match) helm-fuzzy-sort-fn)
-    (set-slot-value source 'filtered-candidate-transformer
-                    (helm-aif (slot-value source 'filtered-candidate-transformer)
-                        (append (helm-mklist it)
-                                (list helm-fuzzy-sort-fn))
-                      (list helm-fuzzy-sort-fn))))
+    (setf (slot-value source 'filtered-candidate-transformer)
+          (helm-aif (slot-value source 'filtered-candidate-transformer)
+              (append (helm-mklist it)
+                      (list helm-fuzzy-sort-fn))
+            (list helm-fuzzy-sort-fn))))
   (unless (slot-value source 'nohighlight)
-    (set-slot-value source 'filtered-candidate-transformer
-                    (helm-aif (slot-value source 'filtered-candidate-transformer)
-                        (append (helm-mklist it)
-                                (list #'helm-fuzzy-highlight-matches))
-                      (list #'helm-fuzzy-highlight-matches)))))
+    (setf (slot-value source 'filtered-candidate-transformer)
+          (helm-aif (slot-value source 'filtered-candidate-transformer)
+              (append (helm-mklist it)
+                      (list #'helm-fuzzy-highlight-matches))
+            (list #'helm-fuzzy-highlight-matches)))))
 
 (defmethod helm-setup-user-source ((_source helm-source)))
 
 (defmethod helm--setup-source ((source helm-source-sync))
   (when (slot-value source 'fuzzy-match)
     (helm-aif (slot-value source 'match)
-        (set-slot-value source 'match (append (helm-mklist it)
-                                              (list helm-fuzzy-match-fn)))
-      (set-slot-value source 'match helm-fuzzy-match-fn)))
+        (setf (slot-value source 'match)
+              (append (helm-mklist it)
+                      (list helm-fuzzy-match-fn)))
+      (setf (slot-value source 'match) helm-fuzzy-match-fn)))
   (when (slot-value source 'matchplugin)
-    (set-slot-value source 'match
-                    (helm-source-mm-get-search-or-match-fns source 'match)))
+    (setf (slot-value source 'match)
+          (helm-source-mm-get-search-or-match-fns source 'match)))
   (helm-aif (and (null (slot-value source 'matchplugin))
                  (slot-value source 'migemo))
       (unless (eq it 'nomultimatch) ; Use own migemo fn.
-        (set-slot-value source 'match
-                        (append (helm-mklist (slot-value source 'match))
-                                '(helm-mm-3-migemo-match))))))
+        (setf (slot-value source 'match)
+              (append (helm-mklist (slot-value source 'match))
+                      '(helm-mm-3-migemo-match))))))
 
 (defmethod helm--setup-source ((source helm-source-in-buffer))
   (let ((cur-init (slot-value source 'init)))
     (helm-aif (slot-value source 'data)
-        (set-slot-value
-         source
-         'init (delq
-                nil
-                (list
-                 (and (null (eq 'helm-default-init-source-in-buffer-function
-                                cur-init))
-                      cur-init)
-                 (lambda ()
-                   (helm-init-candidates-in-buffer
-                       'global
-                     (if (functionp it) (funcall it) it))))))))
+        (setf (slot-value source 'init)
+              (delq
+               nil
+               (list
+                (and (null (eq 'helm-default-init-source-in-buffer-function
+                               cur-init))
+                     cur-init)
+                (lambda ()
+                  (helm-init-candidates-in-buffer
+                      'global
+                    (if (functionp it) (funcall it) it))))))))
   (when (slot-value source 'fuzzy-match)
     (helm-aif (slot-value source 'search)
-        (set-slot-value source 'search (append (helm-mklist it)
-                                               (list helm-fuzzy-search-fn)))
-      (set-slot-value source 'search (list helm-fuzzy-search-fn))))
+        (setf (slot-value source 'search)
+              (append (helm-mklist it)
+                      (list helm-fuzzy-search-fn)))
+      (setf (slot-value source 'search) (list helm-fuzzy-search-fn))))
   (when (slot-value source 'matchplugin)
-    (set-slot-value
-     source 'search (helm-source-mm-get-search-or-match-fns source 'search)))
+    (setf (slot-value source 'search)
+          (helm-source-mm-get-search-or-match-fns source 'search)))
   (helm-aif (and (null (slot-value source 'matchplugin))
                  (slot-value source 'migemo))
       (unless (eq it 'nomultimatch)
-        (set-slot-value source 'search
-                        (append (helm-mklist (slot-value source 'search))
-                                '(helm-mm-3-migemo-search)))))
+        (setf (slot-value source 'search)
+              (append (helm-mklist (slot-value source 'search))
+                      '(helm-mm-3-migemo-search)))))
   (let ((mtc (slot-value source 'match)))
     (cl-assert (or (equal '(identity) mtc)
                    (eq 'identity mtc))

helm-types.el

@@ -71,17 +71,19 @@
 (defmethod helm--setup-source :primary ((_source helm-type-file)))
 
 (defmethod helm--setup-source :before ((source helm-type-file))
-  (set-slot-value source 'action 'helm-type-file-actions)
-  (set-slot-value source 'persistent-help "Show this file")
-  (set-slot-value source 'action-transformer '(helm-transform-file-load-el
-                                               helm-transform-file-browse-url
-                                               helm-transform-file-cache))
-  (set-slot-value source 'candidate-transformer '(helm-skip-boring-files
-                                                  helm-highlight-files
-                                                  helm-w32-pathname-transformer))
-  (set-slot-value source 'help-message 'helm-generic-file-help-message)
-  (set-slot-value source 'mode-line (list "File(s)" helm-mode-line-string))
-  (set-slot-value source 'keymap helm-generic-files-map))
+  (setf (slot-value source 'action) 'helm-type-file-actions)
+  (setf (slot-value source 'persistent-help) "Show this file")
+  (setf (slot-value source 'action-transformer)
+        '(helm-transform-file-load-el
+          helm-transform-file-browse-url
+          helm-transform-file-cache))
+  (setf (slot-value source 'candidate-transformer)
+        '(helm-skip-boring-files
+          helm-highlight-files
+          helm-w32-pathname-transformer))
+  (setf (slot-value source 'help-message) 'helm-generic-file-help-message)
+  (setf (slot-value source 'mode-line) (list "File(s)" helm-mode-line-string))
+  (setf (slot-value source 'keymap) helm-generic-files-map))
 
 
 ;; Bookmarks
@@ -109,11 +111,11 @@
 (defmethod helm--setup-source :primary ((_source helm-type-bookmark)))
 
 (defmethod helm--setup-source :before ((source helm-type-bookmark))
-  (set-slot-value source 'action 'helm-type-bookmark-actions)
-  (set-slot-value source 'keymap helm-bookmark-map)
-  (set-slot-value source 'mode-line (list "Bookmark(s)" helm-mode-line-string))
-  (set-slot-value source 'help-message 'helm-bookmark-help-message)
-  (set-slot-value source 'migemo t))
+  (setf (slot-value source 'action) 'helm-type-bookmark-actions)
+  (setf (slot-value source 'keymap) helm-bookmark-map)
+  (setf (slot-value source 'mode-line) (list "Bookmark(s)" helm-mode-line-string))
+  (setf (slot-value source 'help-message) 'helm-bookmark-help-message)
+  (setf (slot-value source 'migemo) t))
 
 
 ;; Buffers
@@ -159,14 +161,13 @@
 (defmethod helm--setup-source :primary ((_source helm-type-buffer)))
 
 (defmethod helm--setup-source :before ((source helm-type-buffer))
-  (set-slot-value source 'action 'helm-type-buffer-actions)
-  (set-slot-value source 'persistent-help "Show this buffer")
-  (set-slot-value source 'mode-line (list "Buffer(s)" helm-mode-line-string))
-  (set-slot-value
-   source 'filtered-candidate-transformer
-   '(helm-skip-boring-buffers
-     helm-buffers-sort-transformer
-     helm-highlight-buffers)))
+  (setf (slot-value source 'action) 'helm-type-buffer-actions)
+  (setf (slot-value source 'persistent-help) "Show this buffer")
+  (setf (slot-value source 'mode-line) (list "Buffer(s)" helm-mode-line-string))
+  (setf (slot-value source 'filtered-candidate-transformer)
+        '(helm-skip-boring-buffers
+          helm-buffers-sort-transformer
+          helm-highlight-buffers)))
 
 ;; Functions
 (defclass helm-type-function (helm-source) ()
@@ -197,12 +198,12 @@
 (defmethod helm--setup-source :primary ((_source helm-type-function)))
 
 (defmethod helm--setup-source :before ((source helm-type-function))
-  (set-slot-value source 'action 'helm-type-function-actions)
-  (set-slot-value source 'action-transformer
-                  'helm-transform-function-call-interactively)
-  (set-slot-value source 'candidate-transformer
-                  'helm-mark-interactive-functions)
-  (set-slot-value source 'coerce 'helm-symbolify))
+  (setf (slot-value source 'action) 'helm-type-function-actions)
+  (setf (slot-value source 'action-transformer)
+        'helm-transform-function-call-interactively)
+  (setf (slot-value source 'candidate-transformer)
+        'helm-mark-interactive-functions)
+  (setf (slot-value source 'coerce) 'helm-symbolify))
 
 
 ;; Commands
@@ -225,10 +226,9 @@
 (defmethod helm--setup-source :primary ((_source helm-type-command)))
 
 (defmethod helm--setup-source :before ((source helm-type-command))
-  (set-slot-value
-   source 'action 'helm-type-command-actions)
-  (set-slot-value source 'coerce 'helm-symbolify)
-  (set-slot-value source 'persistent-action 'describe-function))
+  (setf (slot-value source 'action) 'helm-type-command-actions)
+  (setf (slot-value source 'coerce) 'helm-symbolify)
+  (setf (slot-value source 'persistent-action) 'describe-function))
 
 ;; Timers
 (defclass helm-type-timers (helm-source) ()
@@ -253,11 +253,11 @@
 (defmethod helm--setup-source :primary ((_source helm-type-timers)))
 
 (defmethod helm--setup-source :before ((source helm-type-timers))
-  (set-slot-value source 'action 'helm-type-timers-actions)
-  (set-slot-value source 'persistent-action
-                  (lambda (tm)
-                    (describe-function (timer--function tm))))
-  (set-slot-value source 'persistent-help "Describe Function"))
+  (setf (slot-value source 'action) 'helm-type-timers-actions)
+  (setf (slot-value source 'persistent-action)
+        (lambda (tm)
+          (describe-function (timer--function tm))))
+  (setf (slot-value source 'persistent-help) "Describe Function"))
 
 ;; Builders.
 (defun helm-build-type-file ()

helm.el

@@ -5382,7 +5382,7 @@ If the source is defined with its own class,
 you can use `helm-setup-user-source' e.g:
 
     (defmethod helm-setup-user-source ((source helm-grep-class))
-      (set-slot-value source 'follow 1))
+      (setf (slot-value source 'follow) 1))
 
 Otherwise, use `helm-attrset' to setup the `follow' attribute of the existing source,
 which see.