From 01db4cb55b43300375d21aaa7a99b682e53e915a Mon Sep 17 00:00:00 2001
From: Georg Brandl <georg@python.org>
Date: Thu, 25 Feb 2016 08:25:01 +0100
Subject: Fix font-locking for Unicode escapes in character literals.

* There is only \u, no \U
* \u requires braces, but allows 1-6 hex digits
---
 rust-mode-tests.el | 12 ++++++++++++
 rust-mode.el       |  3 +--
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/rust-mode-tests.el b/rust-mode-tests.el
index 8390ab6..a99d36b 100644
--- a/rust-mode-tests.el
+++ b/rust-mode-tests.el
@@ -1217,6 +1217,18 @@ list of substrings of `STR' each followed by its face."
      "let" font-lock-keyword-face
      "'\\\\'" font-lock-string-face)))
 
+(ert-deftest font-lock-hex-escape-character-literal ()
+  (rust-test-font-lock
+   "let ch = '\\x1f';"
+   '("let" font-lock-keyword-face
+     "'\\x1f'" font-lock-string-face)))
+
+(ert-deftest font-lock-unicode-escape-character-literal ()
+  (rust-test-font-lock
+   "let ch = '\\u{1ffff}';"
+   '("let" font-lock-keyword-face
+     "'\\u{1ffff}'" font-lock-string-face)))
+
 (ert-deftest font-lock-raw-strings-no-hashes ()
   (rust-test-font-lock
    "r\"No hashes\";"
diff --git a/rust-mode.el b/rust-mode.el
index 686498b..56b356d 100644
--- a/rust-mode.el
+++ b/rust-mode.el
@@ -83,8 +83,7 @@
       (seq
        "\\"
        (or
-        (: "U" (= 8 xdigit))
-        (: "u" (= 4 xdigit))
+        (: "u{" (** 1 6 xdigit) "}")
         (: "x" (= 2 xdigit))
         (any "'nrt0\"\\")))
       (not (any "'\\"))
-- 
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