[vala/wip/baedert/nullable: 10/25] binaryexpression: Fix is_non_null for COALESCE expressions

[Timm Bäder <baedert src gnome org>]

commit 0bdd1975970949a55187f1527f93e5b1bce24fdc
Author: Timm Bäder <mail baedert org>
Date:   Sat Nov 5 21:48:58 2016 +0100

    binaryexpression: Fix is_non_null for COALESCE expressions

 vala/valabinaryexpression.vala |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/vala/valabinaryexpression.vala b/vala/valabinaryexpression.vala
index b081090..7e08f64 100644
--- a/vala/valabinaryexpression.vala
+++ b/vala/valabinaryexpression.vala
@@ -138,6 +138,10 @@ public class Vala.BinaryExpression : Expression {
        }
 
        public override bool is_non_null () {
+               if (operator == BinaryOperator.COALESCE) {
+                       // The coalesce operator makes sure that `right` is taken if left is null
+                       return right.is_non_null ();
+               }
                return left.is_non_null () && right.is_non_null ();
        }