diff --git a/re.c b/re.c
index 0536aa6d8e..9fec950ed9 100644
--- a/re.c
+++ b/re.c
@@ -2950,7 +2950,7 @@ match_hash(VALUE match)
     const struct re_registers *regs;
     st_index_t hashval = rb_hash_start(rb_str_hash(RMATCH(match)->str));
 
-    rb_hash_uint(hashval, reg_hash(RMATCH(match)->regexp));
+    hashval = rb_hash_uint(hashval, reg_hash(RMATCH(match)->regexp));
     regs = RMATCH_REGS(match);
     hashval = rb_hash_uint(hashval, regs->num_regs);
     hashval = rb_hash_uint(hashval, rb_memhash(regs->beg, regs->num_regs * sizeof(*regs->beg)));