invalid_annotation_target hides other errors

In my analysis_options.yaml, I have enabled the invalid_annotation_target rule like so:

  rules:
    invalid_annotation_target: ignore

My project was displaying 0 problems. But I was starting to suspect that something was behaving strangely and I disabled the rule. More than 30 errors were found in my project, among which most of them were:

• file_names
• non_constant_identifier_names
• avoid_returning_null_for_void
• prefer_const_constructors
• ...

I do now understand why there errors are not displayed when invalid_annotation_target is set to ignore?

You should put invalid_annotation_target in analyzer errors, not linter rules. So your analysis_options.yaml should look like this:

include: package:flutter_lints/flutter.yaml

analyzer:
  errors:
    invalid_annotation_target: ignore

This will allow the linter rules you mentioned above to work back as normal.

More info on customizing static analysis and its behavior: https://dart.dev/tools/analysis