@@ -690,11 +690,11 @@
 		return NO;
 
 	return YES;
 }
 
-- (of_comparison_result_t)compare: (id)object
+- (of_comparison_result_t)compare: (id <OFComparing>)object
 {
 	OFString *otherString;
 	size_t otherCStringLength, minimumCStringLength;
 	int compare;
 
@@ -704,11 +704,11 @@
 	if (![object isKindOfClass: [OFString class]])
 		@throw [OFInvalidArgumentException
 		    exceptionWithClass: [self class]
 			      selector: _cmd];
 
-	otherString = object;
+	otherString = (OFString*)object;
 	otherCStringLength = [otherString UTF8StringLength];
 	minimumCStringLength = (s->cStringLength > otherCStringLength
 	    ? otherCStringLength : s->cStringLength);
 
 	if ((compare = memcmp(s->cString, [otherString UTF8String],