this parser for the static checker.
This fixes some outstanding bugs where the static checker differed from the
dynamic one.
Also, fix `%v` to be accepted with POSIX syntax.

Tested:
  Presubmit
  TGP OCL:487237262:BASE:490275393:1669141454896:92dd62e3
PiperOrigin-RevId: 491650577
Change-Id: Id138c108187428b3aea46f8887495f1da12c91b2