| // Copyright (c) 2017, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| import 'package:analyzer/dart/ast/ast.dart'; |
| import 'package:analyzer/dart/ast/visitor.dart'; |
| import 'package:analyzer/dart/element/element.dart'; |
| |
| import '../analyzer.dart'; |
| |
| const _desc = r'Avoid defining unused parameters in constructors.'; |
| |
| const _details = r''' |
| |
| **AVOID** defining unused parameters in constructors. |
| |
| **BAD:** |
| ``` |
| class BadOne { |
| BadOne(int unusedParameter, [String unusedPositional]); |
| } |
| |
| class BadTwo { |
| int c; |
| |
| BadTwo(int a, int b, int x) { |
| c = a + b; |
| } |
| } |
| ``` |
| |
| '''; |
| |
| class AvoidUnusedConstructorParameters extends LintRule |
| implements NodeLintRule { |
| AvoidUnusedConstructorParameters() |
| : super( |
| name: 'avoid_unused_constructor_parameters', |
| description: _desc, |
| details: _details, |
| group: Group.style); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| final visitor = _Visitor(this); |
| registry.addConstructorDeclaration(this, visitor); |
| } |
| } |
| |
| class _ConstructorVisitor extends RecursiveAstVisitor { |
| final LintRule rule; |
| final ConstructorDeclaration element; |
| final Set<FormalParameter> unusedParameters; |
| |
| _ConstructorVisitor(this.rule, this.element) |
| : unusedParameters = element.parameters.parameters |
| .where((p) => |
| p.declaredElement is! FieldFormalParameterElement && |
| !p.declaredElement.hasDeprecated) |
| .toSet(); |
| |
| @override |
| void visitSimpleIdentifier(SimpleIdentifier node) { |
| unusedParameters |
| .removeWhere((p) => node.staticElement == p.declaredElement); |
| } |
| } |
| |
| class _Visitor extends SimpleAstVisitor<void> { |
| final LintRule rule; |
| |
| _Visitor(this.rule); |
| |
| @override |
| void visitConstructorDeclaration(ConstructorDeclaration node) { |
| if (node.redirectedConstructor != null) return; |
| if (node.externalKeyword != null) return; |
| |
| final _constructorVisitor = _ConstructorVisitor(rule, node); |
| node?.body?.visitChildren(_constructorVisitor); |
| node?.initializers?.forEach((i) => i.visitChildren(_constructorVisitor)); |
| |
| _constructorVisitor.unusedParameters.forEach(rule.reportLint); |
| } |
| } |