Analyzing and Fixing Dart Code

Contents

• Analysis Configuration
• Diagnostic Suppression
• Workflow: Executing Static Analysis
• Workflow: Applying Automated Fixes
• Examples

Analysis Configuration

analysis_options.yaml

• Base Configuration: Always include a standard rule set (e.g.,

  package:lints/recommended.yaml

  or

  package:flutter_lints/flutter.yaml

  ) using the

  include:

  directive.
• Strict Type Checks: Enable strict type checks under the

  analyzer: language:

  node to prevent implicit downcasts and dynamic inferences. Set

  strict-casts: true

  ,

  strict-inference: true

  , and

  strict-raw-types: true

  .
• Linter Rules: Explicitly enable or disable specific rules under the

  linter: rules:

  node. Use a key-value map (

  rule_name: true/false

  ) when overriding included rules, or a list (

  - rule_name

  ) when defining a fresh set. Do not mix list and map syntax in the same

  rules

  block.
• Formatter Configuration: Configure

  dart format

  behavior under the

  formatter:

  node. Set

  page_width

  (default 80) and

  trailing_commas

  (

  automate

  or

  preserve

  ).
• Analyzer Plugins: Enable custom diagnostics by adding plugins under the

  analyzer: plugins:

  node. Ensure the plugin package is added as a

  dev_dependency

  in

  pubspec.yaml

  .

Diagnostic Suppression

• File-level Exclusion: Use the

  analyzer: exclude:

  node in

  analysis_options.yaml

  to exclude entire files or directories (e.g.,

  **/*.g.dart

  ) using glob patterns.
• File-level Suppression: Add

  // ignore_for_file: <diagnostic_code>

  at the top of a Dart file to suppress specific diagnostics for the entire file. Use

  // ignore_for_file: type=lint

  to suppress all linter rules.
• Line-level Suppression: Add

  // ignore: <diagnostic_code>

  on the line directly above the offending code, or appended to the end of the offending line.
• Pubspec Suppression: Add

  # ignore: <diagnostic_code>

  above the offending line in

  pubspec.yaml

  files (e.g.,

  # ignore: sort_pub_dependencies

  ).
• Plugin Diagnostics: Prefix the diagnostic code with the plugin name when suppressing plugin-specific issues (e.g.,

  // ignore: some_plugin/some_code

  ).

Workflow: Executing Static Analysis

• 1. Verify

  analysis_options.yaml

  exists at the project root.
• 2. Run the analyzer using the

  analyze_files

  MCP tool (if available) or the CLI command

  dart analyze <target_directory>

  .
• 3. Review the diagnostic output.
• 4. If info-level issues must be treated as failures, append the

  --fatal-infos

  flag.
• 5. Resolve reported errors manually or proceed to the Automated Fixes workflow.

Workflow: Applying Automated Fixes

• 1. Execute a dry run to preview proposed changes using the

  dart_fix

  MCP tool or CLI command

  dart fix --dry-run

  .
• 2. Review the proposed fixes to ensure they align with the intended architecture.
• 3. If additional fixes are required, verify that the corresponding linter rules are enabled in

  analysis_options.yaml

  .
• 4. Apply the fixes using the

  dart_fix

  MCP tool or CLI command

  dart fix --apply

  .
• 5. Format the modified code using the

  dart_format

  MCP tool or CLI command

  dart format .

  .
• 6. Run the static analysis workflow to verify all diagnostics are resolved.

Examples

Comprehensive

analysis_options.yaml

include: package:flutter_lints/recommended.yaml

analyzer:
  exclude:
    - "**/*.g.dart"
    - "lib/generated/**"
  language:
    strict-casts: true
    strict-inference: true
    strict-raw-types: true
  errors:
    todo: ignore
    invalid_assignment: warning
    missing_return: error

linter:
  rules:
    avoid_shadowing_type_parameters: false
    await_only_futures: true
    use_super_parameters: true

formatter:
  page_width: 100
  trailing_commas: preserve

Inline Diagnostic Suppression

// Suppress for the entire file
// ignore_for_file: unused_local_variable, dead_code

void processData() {
  // Suppress for a specific line
  // ignore: invalid_assignment
  int x = ''; 
  
  const y = 10; // ignore: constant_identifier_names
}