2 files changed, 2 insertions, 2 deletions

diff --git a/src/wixext/VSExtensionFactory.cs b/src/wixext/VSExtensionFactory.cs
index cc0d7314..c6e0cc31 100644
--- a/src/wixext/VSExtensionFactory.cs
+++ b/src/wixext/VSExtensionFactory.cs
@@ -8,7 +8,7 @@ namespace WixToolset.VisualStudio
 
     public class VSExtensionFactory : BaseExtensionFactory
     {
-        protected override IEnumerable<Type> ExtensionTypes => new[]
+        protected override IReadOnlyCollection<Type> ExtensionTypes => new[]
         {
             typeof(VSCompiler),
             typeof(VSExtensionData),
diff --git a/src/wixext/VSWindowsInstallerBackendBinderExtension.cs b/src/wixext/VSWindowsInstallerBackendBinderExtension.cs
index 825c8ca7..d0d8648c 100644
--- a/src/wixext/VSWindowsInstallerBackendBinderExtension.cs
+++ b/src/wixext/VSWindowsInstallerBackendBinderExtension.cs
@@ -8,6 +8,6 @@ namespace WixToolset.VisualStudio
 
     public class VSWindowsInstallerBackendBinderExtension : BaseWindowsInstallerBackendBinderExtension
     {
-        public override IEnumerable<TableDefinition> TableDefinitions => VSTableDefinitions.All;
+        public override IReadOnlyCollection<TableDefinition> TableDefinitions => VSTableDefinitions.All;
     }
 }