Index: vala/valasemanticanalyzer.vala
===================================================================
--- vala/valasemanticanalyzer.vala	(revision 602)
+++ vala/valasemanticanalyzer.vala	(working copy)
@@ -870,6 +870,25 @@
 		stmt.variable_declarator.active = true;
 	}
 
+	private bool has_method (DataType data_type, string! method_name)
+	{
+		if (data_type is Interface) {
+			Interface iface = (Interface) data_type;
+			foreach (Method m in iface.get_methods ()) {
+				if (m.parameters.size != 0)
+					continue;
+				if (m.get_full_name () == method_name) {
+					if (m.return_type is iterator_type) {
+						found = true;
+						break;
+					}
+				}
+			 }
+		} else if (data_type is Class) {
+			// TODO
+		}
+	}
+
 	public override void visit_end_foreach_statement (ForeachStatement! stmt) {
 		if (stmt.collection.error) {
 			// ignore inner error
@@ -886,7 +905,7 @@
 		stmt.collection_variable_declarator.active = true;
 
 		var collection_type = stmt.collection.static_type.data_type;
-		if (iterable_type != null && collection_type.is_subtype_of (iterable_type)) {
+		if ((iterable_type != null && collection_type.is_subtype_of (iterable_type)) || has_method (collection_type, "get_iterator")) {
 			stmt.iterator_variable_declarator = new VariableDeclarator ("%s_it".printf (stmt.variable_name));
 			stmt.iterator_variable_declarator.type_reference = new TypeReference ();
 			stmt.iterator_variable_declarator.type_reference.data_type = iterator_type;