"Add type annotations" doesn't handle dynamic correctly

[gspencergoog]

In VSCode, when I use the code suggestion "Add type annotations" and the type includes dynamic, then it will insert <> instead of <dynamic>. I think this feature uses analyzer, which is why I filed this here.

For instance, if I have the following declaration:

final List<dynamic> data = [];

and I invoke "Add type annotation", it produces:

final List<dynamic> data = <>[];

instead of the expected:

final List<dynamic> data = <dynamic>[];

Dart version

• Dart 3.6.0-175.0.dev (dev) (Fri Aug 23 09:07:06 2024 -0700) on "linux_x64"
• on linux / Linux 6.9.10-1rodete4-amd64 Process tests sometimes cause timeout on Linux #1 SMP PREEMPT_DYNAMIC Debian 6.9.10-1rodete4 (2024-08-02)
• locale is en_US.UTF-8
• Dart VSCode extension: v3.96.0

[dart-github-bot]

Summary: The "Add type annotations" feature in VS Code incorrectly inserts <> instead of <dynamic> when the type includes dynamic, leading to invalid code. This issue likely stems from the analyzer's behavior.

[gspencergoog]

Also, if the type is nested, it omits the type when it is explicitly dynamic:

final Map<String, List<dynamic>> data = {'string': []};

maps to:

final Map<String, List<dynamic>> data = <String, List>{'string': <>[]};

Instead of:

final Map<String, List<dynamic>> data = <String, List<dynamic>>{'string': <dynamic>[]};