pkg/linter/lib/src/rules/no_default_cases.dart

// 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/analysis_rule/rule_context.dart';
import 'package:analyzer/analysis_rule/rule_state.dart';
import 'package:analyzer/analysis_rule/rule_visitor_registry.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/ast/visitor.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/dart/element/type.dart';
import 'package:analyzer/error/error.dart';

import '../analyzer.dart';
import '../extensions.dart';

const _desc = r'No default cases.';

class NoDefaultCases extends LintRule {
  NoDefaultCases()
    : super(
        name: LintNames.no_default_cases,
        description: _desc,
        state: const RuleState.experimental(),
      );

  @override
  DiagnosticCode get diagnosticCode => LinterLintCode.noDefaultCases;

  @override
  void registerNodeProcessors(
    RuleVisitorRegistry registry,
    RuleContext context,
  ) {
    var visitor = _Visitor(this);
    registry.addSwitchStatement(this, visitor);
  }
}

class _Visitor extends SimpleAstVisitor<void> {
  final LintRule rule;

  _Visitor(this.rule);

  @override
  void visitSwitchStatement(SwitchStatement statement) {
    var expressionType = statement.expression.staticType;
    if (expressionType is InterfaceType) {
      for (var member in statement.members) {
        if (member is SwitchDefault) {
          var interfaceElement = expressionType.element;
          if (interfaceElement is EnumElement ||
              interfaceElement is ClassElement &&
                  interfaceElement.isEnumLikeClass()) {
            rule.reportAtNode(member);
          }
          return;
        }
      }
    }
  }
}