diff --git a/Source/NSArray.m b/Source/NSArray.m
index 117a9cd9a..fa5694cc4 100644
--- a/Source/NSArray.m
+++ b/Source/NSArray.m
@@ -794,9 +794,20 @@ compare(id elem1, id elem2, void* context)
 {
   NSComparisonResult (*imp)(id, SEL, id);
 
+  if (context == 0)
+    [NSException raise: NSInvalidArgumentException
+		format: @"compare null selector given"];
+
   imp = (NSComparisonResult (*)(id, SEL, id))
     [elem1 methodForSelector: context];
 
+  if (imp == NULL)
+    {
+      [NSException raise: NSGenericException
+		  format: @"invalid selector passed to compare"];
+      return 0;
+    }
+
   return (*imp)(elem1, context, elem2);
 }