tree 4c32b387711415041355f74fe5cf1974fad3f0bb
parent bc6ce1fd924713f487706c98db13e53c369f902c
author Paul Berry <stereotype441@gmail.com> 1519928395 +0100
committer Todd Volkert <tvolkert@users.noreply.github.com> 1519928395 -0800

Make ForwardingDirectory generic. (#74)

Due to an upcoming change in Dart 2.0
(https://github.com/dart-lang/sdk/issues/32148), it will no longer be
allowed for a class to implement the same generic interface in
different ways.  (E.g. a class cannot implement/extend/mixin both
A<int> and A<String>).

This causes problems with _LocalDirectory.  It extends
_LocalFileSystemEntity<_LocalDirectory, Directory>, which extends
ForwardingFileSystemEntity<_LocalDirectory, Directory>, but it mixes
in ForwardingDirectory, which extends
ForwardingFileSystemEntity<Directory, io.Directory>.

The solution is to make ForwardingDirectory a generic mixin, with
ForwardingDirectory<T> extending ForwardingFileSystemEntity<T,
io.Directory>.  Type inference automatically fills in the type
argument T=_LocalDirectory at the site of the declaration of
_LocalDirectory.