have you folks ever see this kind of warnings with dash.el?

/.emacs.d/packs/dev/foundation-pack/vendor/submodules/dash ((2.13.0-31-gb4faa93) %)$ cask
Warning: Unknown defun property `pure' in -remove-item
Warning: Unknown defun property `side-effect-free' in -remove-item
Warning: Unknown defun property `pure' in -non-nil
Warning: Unknown defun property `side-effect-free' in -non-nil
Warning: Unknown defun property `pure' in -replace
Warning: Unknown defun property `side-effect-free' in -replace
Warning: Unknown defun property `pure' in -replace-first
Warning: Unknown defun property `side-effect-free' in -replace-first
Warning: Unknown defun property `pure' in -replace-last
Warning: Unknown defun property `side-effect-free' in -replace-last
Warning: Unknown defun property `pure' in -flatten
Warning: Unknown defun property `side-effect-free' in -flatten
Warning: Unknown defun property `pure' in -flatten-n
Warning: Unknown defun property `side-effect-free' in -flatten-n
Warning: Unknown defun property `pure' in -concat
...many many more...

in emacss, how do I make the string lambda stay as 'lambda' in the buffer, but look like an upsidedown y (and only take the space of 1 char for indentation purposes)

M-x prettify-symbols-mode i think

@qqq I have this in my config

(add-hook
 'clojure-mode-hook
 (lambda ()
   (push '("fn" . ?λ) prettify-symbols-alist)
   (prettify-symbols-mode 1)))

(add-hook
 'lisp-mode-hook
 (lambda ()
   (push '("lambda" . ?λ) prettify-symbols-alist)
   (prettify-symbols-mode 1)))