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

diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index e283b43..8fb3852 100644
--- a/src/semantize/typing.nit
+++ b/src/semantize/typing.nit
@@ -267,7 +267,7 @@ private class TypeVisitor
 		#debug("recv: {recvtype} (aka {unsafe_type})")
 		if recvtype isa MNullType then
 			# `null` only accepts some methods of object.
-			if name == "==" or name == "!=" then
+			if name == "==" or name == "!=" or name == "is_same_instance" then
 				unsafe_type = mmodule.object_type.as_nullable
 			else
 				self.error(node, "Error: Method '{name}' call on 'null'.")
@@ -975,7 +975,7 @@ redef class AForExpr
 			is_col = true
 		end
 
-		if mapit_cla != null and v.is_subtype(ittype, mapit_cla.get_mtype([objcla.mclass_type, objcla.mclass_type.as_nullable])) then
+		if mapit_cla != null and v.is_subtype(ittype, mapit_cla.get_mtype([objcla.mclass_type.as_nullable, objcla.mclass_type.as_nullable])) then
 			# Map Iterator
 			var coltype = ittype.supertype_to(v.mmodule, v.anchor, mapit_cla)
 			var variables = self.variables
@@ -1243,7 +1243,7 @@ redef class AArrayExpr
 		if mtype == null then
 			mtype = v.merge_types(self, mtypes)
 		end
-		if mtype == null then
+		if mtype == null or mtype isa MNullType then
 			v.error(self, "Type Error: ambiguous array type {mtypes.join(" ")}")
 			return
 		end