regcomp.c: Add assertion

This is because coverity thinks this could happen, and jhi and khw don't

1 files changed, 5 insertions, 0 deletions

diff --git a/regcomp.c b/regcomp.c
index 233fd88681..557b517ba6 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -13789,6 +13789,11 @@ parseit:
                     ANYOF_POSIXL_ZERO(ret);
                 }
 
+                /* Coverity thinks it is possible for this to be negative; both
+                 * jhi and khw think it's not, but be safer */
+                assert(! (ANYOF_FLAGS(ret) & ANYOF_POSIXL)
+                       || (namedclass + ((namedclass % 2) ? -1 : 1)) >= 0);
+
                 /* See if it already matches the complement of this POSIX
                  * class */
                 if ((ANYOF_FLAGS(ret) & ANYOF_POSIXL)