From 4d65ef45491b62fbecdb9a24822c216aa96bb34e Mon Sep 17 00:00:00 2001
From: Simonas Kazlauskas <git@kazlauskas.me>
Date: Fri, 10 Jul 2015 22:31:44 +0300
Subject: [PATCH] =?UTF-8?q?Tell=20unicode=20escapes=20can=E2=80=99t=20be?=
 =?UTF-8?q?=20used=20as=20bytes=20earlier/more?=
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---
 src/libsyntax/parse/lexer/mod.rs              | 30 +++++++++----------
 .../parse-fail/issue-23620-invalid-escapes.rs |  8 +++--
 2 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs
index edaac3b09bad..b6a3788dacc3 100644
--- a/src/libsyntax/parse/lexer/mod.rs
+++ b/src/libsyntax/parse/lexer/mod.rs
@@ -738,26 +738,24 @@ impl<'a> StringReader<'a> {
                         return match e {
                             'n' | 'r' | 't' | '\\' | '\'' | '"' | '0' => true,
                             'x' => self.scan_byte_escape(delim, !ascii_only),
-                            'u' if self.curr_is('{') => {
-                                let valid = self.scan_unicode_escape(delim);
-                                if valid && ascii_only {
-                                    self.err_span_(
-                                        start,
-                                        self.last_pos,
+                            'u' => {
+                                let valid = if self.curr_is('{') {
+                                    self.scan_unicode_escape(delim) && !ascii_only
+                                } else {
+                                    self.err_span_(start, self.last_pos,
+                                        "incorrect unicode escape sequence");
+                                    self.help_span_(start, self.last_pos,
+                                        "format of unicode escape sequences is `\\u{…}`");
+                                    false
+                                };
+                                if ascii_only {
+                                    self.err_span_(start, self.last_pos,
                                         "unicode escape sequences cannot be used as a byte or in \
                                         a byte string"
                                     );
-                                    false
-                                } else {
-                                   valid
                                 }
-                            }
-                            'u' if !ascii_only => {
-                                self.err_span_(start, self.last_pos,
-                                    "incomplete unicode escape sequence");
-                                self.help_span_(start, self.last_pos,
-                                    "format of unicode escape sequences is `\\u{…}`");
-                                false
+                                valid
+
                             }
                             '\n' if delim == '"' => {
                                 self.consume_whitespace();
diff --git a/src/test/parse-fail/issue-23620-invalid-escapes.rs b/src/test/parse-fail/issue-23620-invalid-escapes.rs
index 98db3efe114b..1790b9164b7e 100644
--- a/src/test/parse-fail/issue-23620-invalid-escapes.rs
+++ b/src/test/parse-fail/issue-23620-invalid-escapes.rs
@@ -16,7 +16,8 @@ fn main() {
     //~^ ERROR unicode escape sequences cannot be used as a byte or in a byte string
 
     let _ = b'\u';
-    //~^ ERROR unknown byte escape: u
+    //~^ ERROR incorrect unicode escape sequence
+    //~^^ ERROR unicode escape sequences cannot be used as a byte or in a byte string
 
     let _ = b'\x5';
     //~^ ERROR numeric character escape is too short
@@ -35,11 +36,12 @@ fn main() {
     let _ = b"\u{a4a4} \xf \u";
     //~^ ERROR unicode escape sequences cannot be used as a byte or in a byte string
     //~^^ ERROR illegal character in numeric character escape:
-    //~^^^ ERROR unknown byte escape: u
+    //~^^^ ERROR incorrect unicode escape sequence
+    //~^^^^ ERROR unicode escape sequences cannot be used as a byte or in a byte string
 
     let _ = "\u{ffffff} \xf \u";
     //~^ ERROR illegal unicode character escape
     //~^^ ERROR illegal character in numeric character escape:
     //~^^^ ERROR form of character escape may only be used with characters in the range [\x00-\x7f]
-    //~^^^^ ERROR incomplete unicode escape sequence
+    //~^^^^ ERROR incorrect unicode escape sequence
 }