diff --git a/variable.c b/variable.c
index b33725b39e..4c2048b066 100644
--- a/variable.c
+++ b/variable.c
@@ -68,6 +68,7 @@ struct fc_result {
     VALUE klass;
     VALUE path;
     VALUE track;
+    VALUE checked;
     struct fc_result *prev;
 };
 
@@ -114,20 +115,18 @@ fc_i(ID key, VALUE v, void *a)
 	if (!RCLASS_CONST_TBL(value)) return ID_TABLE_CONTINUE;
 	else {
 	    struct fc_result arg;
-	    struct fc_result *list;
 
-	    list = res;
-	    while (list) {
-		if (list->track == value) return ID_TABLE_CONTINUE;
-		list = list->prev;
-	    }
+            if (rb_hash_lookup2(res->checked, value, Qfalse))
+                return ID_TABLE_CONTINUE;
 
 	    arg.name = key;
 	    arg.preferred = res->preferred;
 	    arg.path = 0;
 	    arg.klass = res->klass;
 	    arg.track = value;
+            arg.checked = res->checked;
 	    arg.prev = res;
+            rb_hash_aset(arg.checked, value, Qtrue);
 	    rb_id_table_foreach(RCLASS_CONST_TBL(value), fc_i, &arg);
 	    if (arg.path) {
 		res->path = arg.path;
@@ -155,8 +154,10 @@ find_class_path(VALUE klass, ID preferred)
     arg.path = 0;
     arg.klass = klass;
     arg.track = rb_cObject;
+    arg.checked = rb_ident_hash_new();
     arg.prev = 0;
     if (RCLASS_CONST_TBL(rb_cObject)) {
+        rb_hash_aset(arg.checked, rb_cObject, Qtrue)
 	rb_id_table_foreach(RCLASS_CONST_TBL(rb_cObject), fc_i, &arg);
     }
     if (arg.path) {