| // Copyright (c) 2020, 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/analysis/features.dart'; |
| import 'package:analyzer/dart/ast/ast.dart'; |
| import 'package:analyzer/dart/ast/visitor.dart'; |
| |
| import '../analyzer.dart'; |
| |
| const _desc = r'Use a non-nullable type for a final variable initialized ' |
| 'with a non-nullable value.'; |
| |
| const _details = r''' |
| |
| Use a non-nullable type for a final variable initialized with a non-nullable |
| value. |
| |
| **BAD:** |
| ``` |
| final int? i = 1; |
| ``` |
| |
| **GOOD:** |
| ``` |
| final int i = 1; |
| ``` |
| |
| '''; |
| |
| class UnnecessaryNullableForFinalVariableDeclarations extends LintRule |
| implements NodeLintRule { |
| UnnecessaryNullableForFinalVariableDeclarations() |
| : super( |
| name: 'unnecessary_nullable_for_final_variable_declarations', |
| description: _desc, |
| details: _details, |
| maturity: Maturity.experimental, |
| group: Group.style); |
| |
| @override |
| void registerNodeProcessors( |
| NodeLintRegistry registry, LinterContext context) { |
| if (!context.isEnabled(Feature.non_nullable)) { |
| return; |
| } |
| |
| final visitor = _Visitor(this, context); |
| registry.addCompilationUnit(this, visitor); |
| registry.addFieldDeclaration(this, visitor); |
| registry.addTopLevelVariableDeclaration(this, visitor); |
| registry.addVariableDeclarationStatement(this, visitor); |
| } |
| } |
| |
| class _Visitor extends SimpleAstVisitor<void> { |
| _Visitor(this.rule, this.context); |
| |
| final LintRule rule; |
| final LinterContext context; |
| |
| @override |
| void visitFieldDeclaration(FieldDeclaration node) { |
| for (var variable in node.fields.variables) { |
| if (Identifier.isPrivateName(variable.name.name) || node.isStatic) { |
| _visit(variable); |
| } |
| } |
| } |
| |
| @override |
| void visitTopLevelVariableDeclaration(TopLevelVariableDeclaration node) { |
| node.variables.variables.forEach(_visit); |
| } |
| |
| @override |
| void visitVariableDeclarationStatement(VariableDeclarationStatement node) { |
| node.variables.variables.forEach(_visit); |
| } |
| |
| void _visit(VariableDeclaration variable) { |
| if (!variable.isFinal && !variable.isConst) { |
| return; |
| } |
| if (variable.isSynthetic) { |
| return; |
| } |
| if (variable.initializer == null) { |
| return; |
| } |
| if (variable.declaredElement.type.isDynamic) { |
| return; |
| } |
| if (context.typeSystem.isNullable(variable.declaredElement.type) && |
| context.typeSystem.isNonNullable(variable.initializer.staticType)) { |
| rule.reportLint(variable); |
| } |
| } |
| } |