diff --git a/src/Servers/HttpSys/src/UrlPrefixCollection.cs b/src/Servers/HttpSys/src/UrlPrefixCollection.cs
index f15e96c478..ac92c6591d 100644
--- a/src/Servers/HttpSys/src/UrlPrefixCollection.cs
+++ b/src/Servers/HttpSys/src/UrlPrefixCollection.cs
@@ -7,6 +7,7 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.HttpSys.Internal;
 
 namespace Microsoft.AspNetCore.Server.HttpSys
 {