* lisp/minibuffer.el (completion--twq-all): Try and preserve each

completion's case choice.

Fixes: debbugs:14907

2 files changed, 16 insertions, 0 deletions

diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 62a11e229a1..fde62f1fc4d 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2013-07-30  Stephen Berman  <stephen.berman@gmx.net>
+
+        * minibuffer.el (completion--twq-all): Try and preserve each
+        completion's case choice (bug#14907).
+
 2013-07-30  Lars Magne Ingebrigtsen  <larsi@gnus.org>
 
         * net/network-stream.el (open-network-stream): Mention the new
diff --git a/lisp/minibuffer.el b/lisp/minibuffer.el
index 8bcf3afae05..e07d28a54d0 100644
--- a/lisp/minibuffer.el
+++ b/lisp/minibuffer.el
@@ -568,6 +568,17 @@ for use at QPOS."
                  (cl-assert (string-prefix-p prefix completion 'ignore-case) t)
                  (let* ((new (substring completion (length prefix)))
                         (qnew (funcall qfun new))
+                        (qprefix
+                         (if (not completion-ignore-case)
+                             qprefix
+                           ;; Make qprefix inherit the case from `completion'.
+                           (let* ((rest (substring completion
+                                                   0 (length prefix)))
+                                  (qrest (funcall qfun rest)))
+                             (if (completion--string-equal-p qprefix qrest)
+                                 (propertize qrest 'face
+                                             'completions-common-part)
+                               qprefix))))
                         (qcompletion (concat qprefix qnew)))
                    ;; FIXME: Similarly here, Cygwin's mapping trips this
                    ;; assertion.