[Primary Constructors] Dartdoc Support

[kallentu]

This issue tracks the work needed for supporting primary constructors in Dartdoc.

Resources

Doc Comment Placement: Primary Constructors and beyond https://docs.google.com/document/d/1VEg01kHVuozlLaR4vA3lui3Y1y_C1dEOHNIs0yf599I/edit?tab=t.0#heading=h.x9snb54sjlu9

Estimated Work

TBD

[kallentu]

cc. @szakarias @srawlins @scheglov

This is the tracking issue for Dartdoc. Feel free to update as needed and tag Dartdoc related CLs with this issue.

[lrhn]

Primary constructors themselves may need no changes to DartDoc output, they should be documented just like any other constructor (by its documentation and signature).

Documentation on declaring parameters should be treated as documentation on the corresponding instance variables.

Things to consider:

• If "show source" is supported, should it show a combination of class header and this-declaration in body? (Which may not be adjacent, so maybe something like;

  … class const C<S, T>.name(final int x) …
    …
    this: assert(x >= 0);

• If the constructor itself has no doc-comment, should the class's comment be shown?

For "private name parameters" (which counts as a separate feature) there are things to do for DartDoc.