1 files changed, 1 insertions, 0 deletions
diff --git a/hash.c b/hash.c
index 8234db2b25..dda50abe12 100644
--- a/hash.c
+++ b/hash.c
@@ -70,6 +70,7 @@ rb_any_cmp(a, b)
     if (SYMBOL_P(a) && SYMBOL_P(b)) {
 	return a != b;
     }
+    if (a == Qundef || b == Qundef) return -1;
 
     args[0] = a;
     args[1] = b;