Why does show_help_echo call substitute_command_keys?

["Clément Pit-Claudel" <cpitclaudel@gmail.com>]

Hi emacs-devel,

I'm puzzled by this bit of code in show_help_echo:

  if (STRINGP (help) || NILP (help))
    {
      if (!NILP (Vshow_help_function))
	call1 (Vshow_help_function, Fsubstitute_command_keys (help));
      help_echo_showing_p = STRINGP (help);
    }

This is causing trouble in Flycheck, because we set help-echo properties on error spans and we expect them to be displayed without modifications when users hover over them.  Is there a way to disable command-key- (and quote-) substitution in help-echo strings?

Concrete example:

(with-current-buffer (get-buffer-create "A")
  (erase-buffer)
  (insert "AAA")
  (put-text-property (point-min) (point-max) 'help-echo "Expected a 'list<'a>', got a 'pair<'a,'a>'")
  (pop-to-buffer (current-buffer)))

(put your mouse on the "AAA" part, and notice that the quotes were substituted)

Thanks!
Clément.