types property Null safety

Implementation

final List<ClassMirror> types = currentMirrorSystem()
    .libraries
    .values
    .where((lib) => lib.uri.scheme == "package" || lib.uri.scheme == "file")
    .expand((lib) => lib.declarations.values)
    .whereType<ClassMirror>()
    .where((cm) => firstMetadataOfType<PreventCompilation>(cm) == null)
    .toList();