From: Jean-Christophe Beaupré <jcbrinfo@users.noreply.github.com>
Date: Fri, 24 Mar 2017 04:42:41 +0000 (-0400)
Subject: model: Make the `anchor` parameter of `MType::anchor_to` nullable
X-Git-Url: http://nitlanguage.org

model: Make the `anchor` parameter of `MType::anchor_to` nullable

Refactor the code of `TypeVisitor::anchor_to`.

Signed-off-by: Jean-Christophe Beaupré <jcbrinfo@users.noreply.github.com>
---

diff --git a/src/model/model.nit b/src/model/model.nit
index 35910d3..03d82b14 100644
--- a/src/model/model.nit
+++ b/src/model/model.nit
@@ -904,12 +904,13 @@ abstract class MType
 	# because "redef type U: Y". Therefore, Map[T, U] is bound to
 	# Map[B, Y]
 	#
+	# REQUIRE: `self.need_anchor implies anchor != null`
 	# ENSURE: `not self.need_anchor implies result == self`
 	# ENSURE: `not result.need_anchor`
-	fun anchor_to(mmodule: MModule, anchor: MClassType): MType
+	fun anchor_to(mmodule: MModule, anchor: nullable MClassType): MType
 	do
 		if not need_anchor then return self
-		assert not anchor.need_anchor
+		assert anchor != null and not anchor.need_anchor
 		# Just resolve to the anchor and clear all the virtual types
 		var res = self.resolve_for(anchor, null, mmodule, true)
 		assert not res.need_anchor
@@ -1220,7 +1221,7 @@ class MClassType
 
 	redef fun need_anchor do return false
 
-	redef fun anchor_to(mmodule: MModule, anchor: MClassType): MClassType
+	redef fun anchor_to(mmodule, anchor): MClassType
 	do
 		return super.as(MClassType)
 	end
diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index 0bbe61b..d5cbb46 100644
--- a/src/semantize/typing.nit
+++ b/src/semantize/typing.nit
@@ -81,11 +81,6 @@ private class TypeVisitor
 
 	fun anchor_to(mtype: MType): MType
 	do
-		var anchor = anchor
-		if anchor == null then
-			assert not mtype.need_anchor
-			return mtype
-		end
 		return mtype.anchor_to(mmodule, anchor)
 	end