Add a check to avoid core library default methods that (accidentally) aren't being desugared.
RELNOTES: None.

PiperOrigin-RevId: 186675372
GitOrigin-RevId: f13d6f5b153d8713a8af7e2ba0d5dce0e9a577e8
Change-Id: Ie58fefa56a2eabf67ddaef4b0cea565eede64b45
1 file changed
tree: 9e9e95e36712e0efe8597d153d535729283a0e80
  1. java/
  2. test/