Update re2

third_party/re2/re2/testing/compile_test.cc

 // Copyright 2007 The RE2 Authors.  All Rights Reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 // Test prog.cc, compile.cc
 
 #include <string>
 #include <vector>
 #include "util/test.h"
 #include "re2/regexp.h"
@@ skipping 81 matching lines @@
   { "[^ab]",
     "5. alt -> 3 | 4\n"
     "3. alt -> 1 | 2\n"
     "4. byte [63-ff] -> 6\n"
     "1. byte [00-09] -> 6\n"
     "2. byte [0b-60] -> 6\n"
     "6. match! 0\n" },
   { "[Aa]",
     "1. byte/i [61-61] -> 2\n"
     "2. match! 0\n" },
+  // Issue 20992936
+  { "[[-`]",
+    "1. byte [5b-60] -> 2\n"
+    "2. match! 0\n" },
 };
 
 TEST(TestRegexpCompileToProg, Simple) {
   int failed = 0;
   for (int i = 0; i < arraysize(tests); i++) {
     const re2::Test& t = tests[i];
     Regexp* re = Regexp::Parse(t.regexp, Regexp::PerlX|Regexp::Latin1, NULL);
     if (re == NULL) {
       LOG(ERROR) << "Cannot parse: " << t.regexp;
       failed++;
@@ skipping 50 matching lines @@
   EXPECT_TRUE(prog != NULL);
   EXPECT_EQ(prog->bytemap_range(), arraysize(utf8ranges));
   for (int i = 0; i < arraysize(utf8ranges); i++)
     for (int j = utf8ranges[i].lo; j <= utf8ranges[i].hi; j++)
       EXPECT_EQ(prog->bytemap()[j], i) << " byte " << j;
   delete prog;
   re->Decref();
 }
 
 }  // namespace re2