1 files changed, 1 insertions, 1 deletions

diff --git a/src/wixext/PowerShellExtensionFactory.cs b/src/wixext/PowerShellExtensionFactory.cs
index 22a4ad88..44f836e0 100644
--- a/src/wixext/PowerShellExtensionFactory.cs
+++ b/src/wixext/PowerShellExtensionFactory.cs
@@ -8,7 +8,7 @@ namespace WixToolset.PowerShell
 
     public class PowerShellExtensionFactory : BaseExtensionFactory
     {
-        protected override IEnumerable<Type> ExtensionTypes => new[]
+        protected override IReadOnlyCollection<Type> ExtensionTypes => new[]
         {
             typeof(PSCompiler),
             typeof(PSExtensionData),