From: Jean Privat <jean@pryen.org>
Date: Thu, 18 Jun 2009 20:45:03 +0000 (-0400)
Subject: syntax: extends 'as' and 'isa' warning to nullable
X-Git-Tag: v0.3~220
X-Git-Url: http://nitlanguage.org

syntax: extends 'as' and 'isa' warning to nullable

Example
  var x: nullable T
  var y = x.as(T) # Bad form
  var y = x.as(not null) # Good form
  if x isa T then ... # Bad form
  if x != null then ... # Good form

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

diff --git a/src/syntax/typing.nit b/src/syntax/typing.nit
index 8e48ddf..d070119 100644
--- a/src/syntax/typing.nit
+++ b/src/syntax/typing.nit
@@ -1578,6 +1578,12 @@ special PExpr
 			v.warning(self, "Warning: Expression is already a {ttype}.")
 		else if etype < ttype then
 			v.warning(self, "Warning: Expression is already a {ttype} since it is a {etype}.")
+		else if etype.is_nullable and etype.as_notnull == ttype then
+			if self isa AIsaExpr then
+				v.warning(self, "Warning: Prefer '!= null'.")
+			else
+				v.warning(self, "Warning: Prefer '.as(not null)'.")
+			end
 		end
 	end
 end