Merging r258107:
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r258107 | marshall | 2016-01-18 16:50:37 -0800 (Mon, 18 Jan 2016) | 1 line

Fix PR#26175. Thanks to Josh Petrie for the report and the patch. Reviewed as http://reviews.llvm.org/D16262
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git-svn-id: https://llvm.org/svn/llvm-project/libcxx/branches/release_38@260982 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/regex b/include/regex
index b9dac47..ca455f0 100644
--- a/include/regex
+++ b/include/regex
@@ -4265,6 +4265,9 @@
     if (__first != __last && *__first == '\\')
     {
         _ForwardIterator __t1 = _VSTD::next(__first);
+        if (__t1 == __last)
+            __throw_regex_error<regex_constants::error_escape>();
+
         _ForwardIterator __t2 = __parse_decimal_escape(__t1, __last);
         if (__t2 != __t1)
             __first = __t2;
diff --git a/test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp b/test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp
index 4da4d95..9459cd7 100644
--- a/test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp
+++ b/test/std/re/re.regex/re.regex.construct/bad_escape.pass.cpp
@@ -33,6 +33,7 @@
 {
     assert(error_escape_thrown("[\\a]"));
     assert(error_escape_thrown("\\a"));
+    assert(error_escape_thrown("\\"));
 
     assert(error_escape_thrown("[\\e]"));
     assert(error_escape_thrown("\\e"));