diff --git a/meta.lua b/meta.lua
index 59013a7..1e97d6f 100644
--- a/meta.lua
+++ b/meta.lua
@@ -15,7 +15,7 @@ local meta = {}
 function meta.isinstance(obj, cls)
     repeat
         local m = getmetatable(obj)
-        if m == cls then return true end
+        if rawequal(m, cls) then return true end
 
         obj = m
     until obj == nil