After .NET 4.5 .NET Framework has changed the System.ComponentModel.Composition ReflectionModelServices.IsExportFactoryImportDefinition to not throw:

        public static bool IsExportFactoryImportDefinition(ImportDefinition importDefinition)
        {
            Requires.NotNull(importDefinition, "importDefinition");

            return (importDefinition is IPartCreatorImportDefinition);
        }

We still seem to have a snapshot of that code that throws:

It would be nice to update that to match the latest .NET Framework sources.

This is blocking VSMEF here:
https://github.com/Microsoft/vs-mef/blob/9eb8e1d42918ad8d4a422f2dd005df0f96089599/src/Microsoft.VisualStudio.Composition/Configuration/NetFxAdapters.cs#L158-L161