| // Copyright (c) 2015, 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'; |
| |
| const _desc = r'Declare method return types.'; |
| |
| const _details = r''' |
| |
| **DO** declare method return types. |
| |
| When declaring a method or function *always* specify a return type. |
| Declaring return types for functions helps improve your codebase by allowing the |
| analyzer to more adequately check your code for errors that could occur during |
| runtime. |
| |
| **BAD:** |
| ```dart |
| main() { } |
| |
| _bar() => _Foo(); |
| |
| class _Foo { |
| _foo() => 42; |
| } |
| ``` |
| |
| **GOOD:** |
| ```dart |
| void main() { } |
| |
| _Foo _bar() => _Foo(); |
| |
| class _Foo { |
| int _foo() => 42; |
| } |
| |
| typedef predicate = bool Function(Object o); |
| ``` |
| |
| '''; |
| |
| class AlwaysDeclareReturnTypes extends LintRule implements NodeLintRule { |
| AlwaysDeclareReturnTypes() |
| : super( |
| name: 'always_declare_return_types', |
| description: _desc, |
| details: _details, |
| group: Group.style); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| var visitor = _Visitor(this); |
| registry.addFunctionDeclaration(this, visitor); |
| registry.addFunctionTypeAlias(this, visitor); |
| registry.addMethodDeclaration(this, visitor); |
| } |
| } |
| |
| class _Visitor extends SimpleAstVisitor<void> { |
| static const LintCode functionCode = LintCode( |
| "always_declare_return_types", // ignore: prefer_single_quotes |
| "The function {0} should have a return type but doesn't.", |
| correction: |
| "Try adding a return type to the function."); // ignore: prefer_single_quotes |
| |
| static const LintCode methodCode = LintCode( |
| "always_declare_return_types", // ignore: prefer_single_quotes |
| "The method {0} should have a return type but doesn't.", |
| correction: |
| "Try adding a return type to the method."); // ignore: prefer_single_quotes |
| |
| final LintRule rule; |
| |
| _Visitor(this.rule); |
| |
| @override |
| void visitFunctionDeclaration(FunctionDeclaration node) { |
| if (!node.isSetter && node.returnType == null) { |
| rule.reportLint(node.name, |
| arguments: [node.name.name], errorCode: functionCode); |
| } |
| } |
| |
| @override |
| void visitFunctionTypeAlias(FunctionTypeAlias node) { |
| if (node.returnType == null) { |
| rule.reportLint(node.name, |
| arguments: [node.name.name], errorCode: functionCode); |
| } |
| } |
| |
| @override |
| void visitMethodDeclaration(MethodDeclaration node) { |
| if (!node.isSetter && |
| node.returnType == null && |
| node.name.token.type != TokenType.INDEX_EQ) { |
| rule.reportLint(node.name, |
| arguments: [node.name.name], errorCode: methodCode); |
| } |
| } |
| } |