[libc++] Validate the entire regex is consumed

This change would have warned about the bug found in D62451.
No unit tests since the exception should never throw.

Differential Revision: https://reviews.llvm.org/D62452

1 files changed, 2 insertions, 0 deletions

diff --git a/libcxx/src/regex.cpp b/libcxx/src/regex.cpp
index a971f646459..d31e4948743 100644
--- a/libcxx/src/regex.cpp
+++ b/libcxx/src/regex.cpp
@@ -53,6 +53,8 @@ make_error_type_string(regex_constants::error_type ecode)
         return "An invalid regex grammar has been requested.";
     case regex_constants::__re_err_empty:
         return "An empty regex is not allowed in the POSIX grammar.";
+    case regex_constants::__re_err_parse:
+        return "The parser did not consume the entire regular expression.";
     default:
         break;
     }