X-Git-Url: http://nitlanguage.org

diff --git a/src/modelize/modelize_class.nit b/src/modelize/modelize_class.nit
index e36a3ae..8164668 100644
--- a/src/modelize/modelize_class.nit
+++ b/src/modelize/modelize_class.nit
@@ -274,10 +274,19 @@ redef class ModelBuilder
 		if mclassdef.is_intro and objectclass != null then
 			if mclass.kind == extern_kind and mclass.name != "Pointer" then
 				# it is an extern class, but not a Pointer
+				if pointerclass == null then
+					error(nclassdef, "Error: `Pointer` must be defined first.")
+					return
+				end
 				if specpointer then supertypes.add pointerclass.mclass_type
-			else if specobject and mclass.name != "Object" then
-				# it is a standard class without super class (but is not Object)
-				supertypes.add objectclass.mclass_type
+			else if specobject then
+				if mclass.name != "Object" then
+					# it is a standard class without super class (but is not Object)
+					supertypes.add objectclass.mclass_type
+				else if mclass.kind != interface_kind then
+					error(nclassdef, "Error: `Object` must be an {interface_kind}.")
+					return
+				end
 			end
 		end