[BUG] async*/yield Stream building function triggers avoid-redundant-async

[pitazzo]

• Dart code metrics version: 4.19.1
• Dart sdk version: 2.18.2

Please show your full configuration:

Configuration

include: package:flutter_lints/flutter.yaml

linter:
  rules:
    constant_identifier_names: false
    prefer_single_quotes: true
    sort_pub_dependencies: true

analyzer:
  plugins:
    - dart_code_metrics
  exclude:
    - test/**/*.dart

dart_code_metrics:
  anti-patterns:
    - long-method
  metrics:
    cyclomatic-complexity: 20
    maximum-nesting-level: 5
    number-of-parameters: 4
    source-lines-of-code: 50
  metrics-exclude:
    - test/**
    - lib/injector.config.dart
  rules-exclude:
    - lib/injector.config.dart
  rules:
    - always-remove-listener
    - avoid-border-all
    - avoid-collection-methods-with-unrelated-types
    - avoid-dynamic
    - avoid-global-state
    - avoid-late-keyword
    - avoid-missing-enum-constant-in-map
    - avoid-nested-conditional-expressions
    - avoid-redundant-async
    - avoid-throw-in-catch-block
    - avoid-top-level-members-in-tests
    - avoid-unnecessary-type-assertions
    - avoid-unnecessary-type-casts
    - avoid-unused-parameters
    - binary-expression-operand-order
    - double-literal-format
    - member-ordering-extended:
        order:
          - public-fields
          - private-fields
          - constructors
          - public-getters
          - private-getters
          - public-methods
          - private-methods
    - no-boolean-literal-compare
    - no-empty-block
    - no-equal-arguments
    - no-equal-then-else
    - no-object-declaration
    - prefer-async-await
    - prefer-commenting-analyzer-ignores
    - prefer-conditional-expressions
    - prefer-correct-identifier-length:
        exceptions:
          - i
          - x
          - y
          - z
    - prefer-correct-test-file-name
    - prefer-correct-type-name:
        max-length: 44
    - prefer-enums-by-name
    - prefer-first
    - prefer-immediate-return
    - prefer-iterable-of
    - prefer-last
    - prefer-match-file-name
    - prefer-moving-to-variable
    - prefer-trailing-comma

What did you do? Please include the source code example causing the issue.
I have used the async*/yield syntax to build a stream

  Stream<int> buildStream() async* {
    for (int i = 0; i < 10; i++) {
      yield i;
    }
  }

What did you expect to happen?
As the async*keyword is mandatory to create such streams, I expected no rule to be reported.

What actually happened?
avoid-redundant-async rules was reported.

Are you willing to submit a pull request to fix this bug?
Would love to do so, but I think I don't have the time nor the expertise to do it.

[incendial]

Available in 4.20.0 🚀