Fix display of minibuffer prompt in ido.el

* lisp/minibuffer.el (minibuffer--message-overlay-pos): New
function.
(set-minibuffer-message): Use it to determine where to show the
overlay with the temporary message.
* lisp/ido.el (ido-exhibit): Revert "Render Ido suggestions using
an overlay"; this restores the original code which inserted the
match-status information into the minibuffer, instead of
displaying it in an overlay with an after-string.  Put the special
'minibuffer-message' text property at the beginning of the
inserted text.  (Bug#39379)

* etc/NEWS:
* doc/lispref/display.texi (Displaying Messages):
* doc/lispref/text.texi (Special Properties): Document the
'minibuffer-message' text property and its effect.

1 files changed, 6 insertions, 0 deletions

diff --git a/etc/NEWS b/etc/NEWS
index 54a71c9e494..312869fe57e 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -3591,6 +3591,12 @@ Setting this on the first character of a help string disables
 conversions via 'substitute-command-keys'.
 
 +++
+** New text property 'minibuffer-message'.
+Setting this on a character of the minibuffer text will display the
+temporary echo messages before that character, when messages need to
+be displayed while minibuffer is active.
+
++++
 ** 'undo' can be made to ignore the active region for a command
 by setting 'undo-inhibit-region' symbol property of that command to
 non-nil.  This is used by 'mouse-drag-region' to make the effect