[vala] Fix crash when using postfix expressions with read-only properties

[Jürg Billeter <juergbi src gnome org>]

commit 24be8d8e51f3302db40460f667b15d8412842de0
Author: Jürg Billeter <j bitron ch>
Date:   Mon Sep 14 17:37:45 2009 +0200

    Fix crash when using postfix expressions with read-only properties
    
    Fixes bug 595145.

 vala/valapostfixexpression.vala |   16 +++++++++++++++-
 1 files changed, 15 insertions(+), 1 deletions(-)
---
diff --git a/vala/valapostfixexpression.vala b/vala/valapostfixexpression.vala
index 3157c67..1ed72e1 100644
--- a/vala/valapostfixexpression.vala
+++ b/vala/valapostfixexpression.vala
@@ -1,6 +1,6 @@
 /* valapostfixexpression.vala
  *
- * Copyright (C) 2006-2008  Jürg Billeter
+ * Copyright (C) 2006-2009  Jürg Billeter
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -100,6 +100,20 @@ public class Vala.PostfixExpression : Expression {
 			return false;
 		}
 
+		if (inner is MemberAccess) {
+			var ma = (MemberAccess) inner;
+
+			if (ma.symbol_reference is Property) {
+				var prop = (Property) ma.symbol_reference;
+
+				if (prop.set_accessor == null || !prop.set_accessor.writable) {
+					ma.error = true;
+					Report.error (ma.source_reference, "Property `%s' is read-only".printf (prop.get_full_name ()));
+					return false;
+				}
+			}
+		}
+
 		value_type = inner.value_type;
 
 		return !error;