[vala] Fix crash on assignment to array length field

[Jürg Billeter <juergbi src gnome org>]

commit c54cf9d8adf4ee76e03729b1cd0596238b352e8f
Author: Jürg Billeter <j bitron ch>
Date:   Wed Feb 23 08:13:44 2011 +0100

    Fix crash on assignment to array length field

 vala/valaassignment.vala |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/vala/valaassignment.vala b/vala/valaassignment.vala
index 9fb81c6..7d34ce5 100644
--- a/vala/valaassignment.vala
+++ b/vala/valaassignment.vala
@@ -471,7 +471,8 @@ public class Vala.Assignment : Expression {
 
 			if (operator == AssignmentOperator.SIMPLE &&
 			    (local != null || param != null || field != null) &&
-			    !is_array_add ()) {
+			    !is_array_add () &&
+			    !(field is ArrayLengthField)) {
 				// visit_assignment not necessary
 				if (instance && ma.inner != null) {
 					ma.inner.emit (codegen);