diff --git a/src/Workspaces.Core/Host/Mef/MefLanguageServices.cs b/src/Workspaces.Core/Host/Mef/MefLanguageServices.cs
index ba01be647d..956898660e 100644
--- a/src/Workspaces.Core/Host/Mef/MefLanguageServices.cs
+++ b/src/Workspaces.Core/Host/Mef/MefLanguageServices.cs
@@ -53,7 +53,7 @@ internal bool TryGetService(Type serviceType, out Lazy<ILanguageService, Languag
                 serviceType,
                 type =>
                 {
-                    string fullName = type.FullName;
+                    string fullName = type.AssemblyQualifiedName;
 
                     return _services.SingleOrDefault(lz => lz.Metadata.ServiceType == fullName, shouldThrow: false);
                 });