Case insensitive find character in `evil` and `evil-easymotion`

Question

I wonder whether it is possible to make f in evil and/or in evil-easymotion case insensitive?

Answer 1

There is no setting to do this for Evil's f. If you inspect the command's definition you'll find that it binds case-fold-search to nil which makes Emacs treat search results case-sensitively. What you can do here is copying its definition, renaming the command and changing the value of case-fold-search to t, then binding the renamed command to the original key:

(evil-define-motion my-evil-find-char (count char)
    "Move to the next COUNT'th occurrence of CHAR.
Movement is restricted to the current line unless `evil-cross-lines' is non-nil."
    :type inclusive
    (interactive "<c><C>")
    (setq count (or count 1))
    (let ((fwd (> count 0)))
      (setq evil-last-find (list #'evil-find-char char fwd))
      (when fwd (forward-char))
      (let ((case-fold-search t))
        (unless (prog1
                    (search-forward (char-to-string char)
                                    (unless evil-cross-lines
                                      (if fwd
                                          (line-end-position)
                                        (line-beginning-position)))
                                    t count)
                  (when fwd (backward-char)))
          (user-error "Can't find %c" char)))))

(with-eval-after-load 'evil
  (define-key evil-motion-state-map (kbd "f") 'my-evil-find-char))

Exercise left to the reader: Doing the equivalent for F and easy-motion commands.