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

diff --git a/src/metamodel/type_formal.nit b/src/metamodel/type_formal.nit
index fcbcb87..e214218 100644
--- a/src/metamodel/type_formal.nit
+++ b/src/metamodel/type_formal.nit
@@ -22,33 +22,30 @@ import inheritance
 
 redef class MMType
 	# The type a indirect type refers to
-	meth direct_type: MMType do return self
+	fun direct_type: MMType do return self
 end
 
 # Formal types are named indirect types
 class MMTypeFormal
 special MMType
-	redef meth is_valid do return _bound != null
+	redef fun is_valid do return _bound != null and _bound.is_valid
 
 	# The name of the type
-	readable attr _name: Symbol 
+	readable var _name: Symbol
 
 	# The type refered
-	meth bound: MMType
-	do
-		assert is_valid
-		return _bound
-	end
-	attr _bound: MMType
+	fun bound: MMType do return _bound.as(not null)
+	var _bound: nullable MMType
 
-	redef meth <(t) do return t != null and (t == self or t.is_supertype(_bound))
-	redef meth is_supertype(t) do return _bound.is_supertype(t)
-	redef meth direct_type do return _bound.direct_type
-	redef meth local_class do return _bound.local_class
+	redef fun <(t) do return t == self or t.is_supertype(bound)
+	redef fun is_supertype(t) do return _bound.is_supertype(t)
+	redef fun is_nullable do return _bound.is_nullable
+	redef fun direct_type do return _bound.direct_type
+	redef fun local_class do return _bound.local_class
 
-	redef meth to_s do return _name.to_s
+	redef fun to_s do return _name.to_s
 
-	protected init(name: Symbol, bound: MMType)
+	protected init(name: Symbol, bound: nullable MMType)
 	do
 		_name = name
 		_bound = bound