From: Jean Privat <jean@pryen.org>
Date: Thu, 18 Jun 2015 01:51:44 +0000 (-0400)
Subject: typing: warn about useless null when the target is always `null`
X-Git-Tag: v0.7.6~21^2~2
X-Git-Url: http://nitlanguage.org

typing: warn about useless null when the target is always `null`

Signed-off-by: Jean Privat <jean@pryen.org>
---

diff --git a/src/semantize/typing.nit b/src/semantize/typing.nit
index f231d4b..86e5bcb 100644
--- a/src/semantize/typing.nit
+++ b/src/semantize/typing.nit
@@ -217,6 +217,10 @@ private class TypeVisitor
 	# Else return true.
 	fun check_can_be_null(anode: ANode, mtype: MType): Bool
 	do
+		if mtype isa MNullType then
+			modelbuilder.warning(anode, "useless-null-test", "Warning: expression is always `null`.")
+			return true
+		end
 		if can_be_null(mtype) then return true
 
 		if mtype isa MFormalType then