From 5241919f48c3bf54fbe8d4e9d50b4a55038da150 Mon Sep 17 00:00:00 2001
From: kennytm <kennytm@gmail.com>
Date: Mon, 29 Oct 2018 20:24:15 +0800
Subject: [PATCH] syntax: fix [[:blank:]] character class

Ensure `[[:blank:]]` only matches `[ \t]`. It appears that there was
a transcription error when `regex-syntax` was rewritten such that
`[[:blank:]]` ended up matching more than it was supposed to.

Fixes #533
---
 regex-syntax/src/hir/translate.rs |  2 +-
 tests/regression.rs               | 17 +++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/regex-syntax/src/hir/translate.rs b/regex-syntax/src/hir/translate.rs
index 8fea00b164..ba0ac0a20a 100644
--- a/regex-syntax/src/hir/translate.rs
+++ b/regex-syntax/src/hir/translate.rs
@@ -1040,7 +1040,7 @@ fn ascii_class(kind: &ast::ClassAsciiKind) -> &'static [(char, char)] {
             X
         }
         Blank => {
-            const X: T = &[(' ', '\t')];
+            const X: T = &[('\t', '\t'), (' ', ' ')];
             X
         }
         Cntrl => {
diff --git a/tests/regression.rs b/tests/regression.rs
index a09333e2c3..bda63f0bcd 100644
--- a/tests/regression.rs
+++ b/tests/regression.rs
@@ -92,3 +92,20 @@ ismatch!(
     r"typename type\-parameter\-\d+\-\d+::.+",
     "test",
     false);
+
+// See: https://github.com/rust-lang/regex/issues/533
+ismatch!(
+    blank_matches_nothing_between_space_and_tab,
+    r"[[:blank:]]",
+    "\u{a}\u{b}\u{c}\u{d}\u{e}\u{f}\
+    \u{10}\u{11}\u{12}\u{13}\u{14}\u{15}\u{16}\u{17}\
+    \u{18}\u{19}\u{1a}\u{1b}\u{1c}\u{1d}\u{1e}\u{1f}",
+    false);
+
+ismatch!(
+    inverted_blank_matches_everything_between_space_and_tab,
+    r"^[[:^blank:]]+$",
+    "\u{a}\u{b}\u{c}\u{d}\u{e}\u{f}\
+    \u{10}\u{11}\u{12}\u{13}\u{14}\u{15}\u{16}\u{17}\
+    \u{18}\u{19}\u{1a}\u{1b}\u{1c}\u{1d}\u{1e}\u{1f}",
+    true);