diff --git a/ICSharpCode.NRefactory/CSharp/Ast/CompilationUnit.cs b/ICSharpCode.NRefactory/CSharp/Ast/CompilationUnit.cs
index 9a50477191..6053d6848e 100644
--- a/ICSharpCode.NRefactory/CSharp/Ast/CompilationUnit.cs
+++ b/ICSharpCode.NRefactory/CSharp/Ast/CompilationUnit.cs
@@ -25,6 +25,9 @@
 // THE SOFTWARE.
 using System;
 using System.Collections.Generic;
+using System.Linq;
+
+using ICSharpCode.NRefactory.Utils;
 
 namespace ICSharpCode.NRefactory.CSharp
 {