1 files changed, 1 insertions, 0 deletions
diff --git a/re.c b/re.c
index 5030519fc9..fdccea434a 100644
--- a/re.c
+++ b/re.c
@@ -1883,6 +1883,7 @@ match_captures(VALUE match)
 static int
 name_to_backref_number(struct re_registers *regs, VALUE regexp, const char* name, const char* name_end)
 {
+    if (NIL_P(regexp)) return -1;
     return onig_name_to_backref_number(RREGEXP_PTR(regexp),
 	(const unsigned char *)name, (const unsigned char *)name_end, regs);
 }