make QualifiedName a value type (#19626)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/19626
ghimport-source-id: 20f03b245245a7fab1c175cebc41e477b1eadc68
Reviewed By: shannonzhu
Differential Revision: D15049582
Pulled By: suo
fbshipit-source-id: 9e73a1d8ee8aa1849880815fa6fddebca408b8b4
