diff --git a/NSArray.m b/NSArray.m
index c4640a94d..d5b12866c 100644
--- a/NSArray.m
+++ b/NSArray.m
@@ -564,6 +564,11 @@
 	    if (RTEST(test)) {
 		return LONG2NUM(i);
 	    }
+	    const long n = [rcv count];
+	    if (n < i) {
+		// Array was modified.
+		i = n;
+	    }
 	}
     }
     else {