[vala] Fix critical on method varargs introduced by 7b6ee1be

[Luca Bruno <lucabru src gnome org>]

commit 9bf7a115525ab76ec71a7763c9e60b5ecaccac2e
Author: Luca Bruno <lucabru src gnome org>
Date:   Sat Sep 6 09:32:09 2014 +0200

    Fix critical on method varargs introduced by 7b6ee1be
    
    Fixes bug 736168

 vala/valasemanticanalyzer.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/vala/valasemanticanalyzer.vala b/vala/valasemanticanalyzer.vala
index 2f1be1b..20600d3 100644
--- a/vala/valasemanticanalyzer.vala
+++ b/vala/valasemanticanalyzer.vala
@@ -571,7 +571,7 @@ public class Vala.SemanticAnalyzer : CodeVisitor {
                return true;
        }
 
-       public bool check_variadic_arguments (Iterator<Expression> arg_it, int i, SourceReference 
source_reference) {
+       public bool check_variadic_arguments (Iterator<Expression>? arg_it, int i, SourceReference 
source_reference) {
                while (arg_it != null && arg_it.next ()) {
                        var arg = arg_it.get ();
                        if (arg.error) {