This CL updates the spec_parser grammar Dart.g such that it corresponds
more precisely to the grammar in the language specification.
Main corrections:
fieldFormalParameter now allows `?` on the parameter type.
cascade was reorganized in the spec, Dart.g now reorganized similarly.
`?` removed from argumentPart (we did not add null-aware invocation)
Other changes were mainly renamings and simplifications of rules, to
make them more similar to the version in the specification.
Change-Id: I1a9bc0097fe6b260dfa6657c947840f2deb437b3
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/167805
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>
Commit-Queue: Erik Ernst <eernst@google.com>
Erik Ernst
67c703063d