| // Copyright (c) 2018, 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/token.dart'; |
| import 'package:analyzer/dart/ast/visitor.dart'; |
| |
| import '../analyzer.dart'; |
| import '../ast.dart'; |
| |
| const _desc = r'Prefer const over final for declarations.'; |
| |
| const _details = r''' |
| |
| **PREFER** using `const` for const declarations. |
| |
| Const declarations are more hot-reload friendly and allow to use const |
| constructors if an instantiation references this declaration. |
| |
| **GOOD:** |
| ``` |
| const o = <int>[]; |
| |
| class A { |
| static const o = <int>[]; |
| } |
| ``` |
| |
| **BAD:** |
| ``` |
| final o = const <int>[]; |
| |
| class A { |
| static final o = const <int>[]; |
| } |
| ``` |
| |
| '''; |
| |
| class PreferConstDeclarations extends LintRule implements NodeLintRule { |
| PreferConstDeclarations() |
| : super( |
| name: 'prefer_const_declarations', |
| description: _desc, |
| details: _details, |
| group: Group.style); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| final visitor = _Visitor(this, context); |
| registry.addFieldDeclaration(this, visitor); |
| registry.addTopLevelVariableDeclaration(this, visitor); |
| registry.addVariableDeclarationStatement(this, visitor); |
| } |
| } |
| |
| class _Visitor extends SimpleAstVisitor<void> { |
| final LintRule rule; |
| |
| final LinterContext context; |
| |
| _Visitor(this.rule, this.context); |
| |
| @override |
| void visitFieldDeclaration(FieldDeclaration node) { |
| if (!node.isStatic) return; |
| _visitVariableDeclarationList(node.fields); |
| } |
| |
| @override |
| void visitTopLevelVariableDeclaration(TopLevelVariableDeclaration node) => |
| _visitVariableDeclarationList(node.variables); |
| |
| @override |
| void visitVariableDeclarationStatement(VariableDeclarationStatement node) => |
| _visitVariableDeclarationList(node.variables); |
| |
| void _visitVariableDeclarationList(VariableDeclarationList node) { |
| if (node.isConst) return; |
| if (!node.isFinal) return; |
| if (node.variables.every((declaration) { |
| var initializer = declaration.initializer; |
| return initializer != null && |
| (initializer is! TypedLiteral || |
| (initializer.beginToken?.keyword == Keyword.CONST)) && |
| !hasConstantError(context, initializer); |
| })) { |
| rule.reportLint(node); |
| } |
| } |
| } |