This CL adds tests in language/external_abstract_fields, testing the
support for abstract instance variables, and for external top-level,
class, and instance variables. It is tested that the syntax of
supported declarations is accepted, and a number of non-supported
forms are rejected, and abstract fields are tested at run time as well.
The implementation of external fields is provided by an implementation
specific mechanism, and no tests are added for any such mechanisms
(that is, with external fields we only test errors).
This CL also updates the spec grammar Dart.g to include grammar
rules for the new kinds of declarations, and it has been verified that
the new tests are passing, respectively cause syntax errors, as
indicated in the test files.
The tests are a further development of the ones in
https://dart-review.googlesource.com/c/sdk/+/145862.
Change-Id: I13be746a05d5acf0117d8cb22151bd9863a71a78
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/148324
Commit-Queue: Erik Ernst <eernst@google.com>
Reviewed-by: Lasse R.H. Nielsen <lrn@google.com>
Erik Ernst