2 files changed, 2 insertions, 2 deletions

diff --git a/src/wixext/SqlExtensionFactory.cs b/src/wixext/SqlExtensionFactory.cs
index e7fafed2..279106d3 100644
--- a/src/wixext/SqlExtensionFactory.cs
+++ b/src/wixext/SqlExtensionFactory.cs
@@ -8,7 +8,7 @@ namespace WixToolset.Sql
 
     public class SqlExtensionFactory : BaseExtensionFactory
     {
-        protected override IEnumerable<Type> ExtensionTypes => new[]
+        protected override IReadOnlyCollection<Type> ExtensionTypes => new[]
         {
             typeof(SqlCompiler),
             typeof(SqlExtensionData),
diff --git a/src/wixext/SqlWindowsInstallerBackendExtension.cs b/src/wixext/SqlWindowsInstallerBackendExtension.cs
index b679e871..2ccdcc56 100644
--- a/src/wixext/SqlWindowsInstallerBackendExtension.cs
+++ b/src/wixext/SqlWindowsInstallerBackendExtension.cs
@@ -8,6 +8,6 @@ namespace WixToolset.Sql
 
     public class SqlWindowsInstallerBackendBinderExtension : BaseWindowsInstallerBackendBinderExtension
     {
-        public override IEnumerable<TableDefinition> TableDefinitions => SqlTableDefinitions.All;
+        public override IReadOnlyCollection<TableDefinition> TableDefinitions => SqlTableDefinitions.All;
     }
 }