Implement generic function type syntax in dartdoc

[bwilkerson]

This is the dartdoc-implementation issue for dart-lang/sdk#27527.

[devoncarew]

punted to 1.23

[mit-mit]

@devoncarew who should this be assigned to?

[jcollins-g]

I'm willing to take a look, but it looks like from the description, it will be dependent on analyzer support.

[devoncarew]

@jcollins-g, thanks! If this needs a new analyzer library, we can either backport the necessary work to the 0.29 release of analyzer, release an entirely new 0.30 version, or solve the issue by moving dartdoc into the sdk repo.

[devoncarew]

It looks like dart_style (dart-lang/dart_style#563) will also need a version of the analyzer w/ generic function type support.

[mit-mit]

Analyzer is done!

[jcollins-g]

I'll start looking at this today.

[dgrove]

The last full push to trunk is Wednesday early morning. Is this likely to land by then?

[jcollins-g]

Implementation & tests complete, assuming I understand the feature correctly. Blocking on landing of cl 2778253002, landing a backport of this and related CLs to the analyzer 0.29 branch in SDK, publishing the new analyzer package, and then submitting my change to dartdoc. So it is going to be hard to get all that done in the next several hours.

Declared NewGenericTypedef as below:

/// A typedef with the new style generic function syntax.
typedef NewGenericTypedef<T> = List<T> Function<T>(int);

Screenshots:

[keertip]

Looks good! See the generic type info 👍

[jcollins-g]

@bwilkerson I think these are the blocking items we need from analyzer:

• CL 2778253002 must land
• Above CL and other CLs needed to make this analyze cleanly must be published in an analyzer package, so we can avoid errors like line 126-132 here