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

// Copyright (c) 2016, 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/analysis_rule.dart';
import 'package:analyzer/analysis_rule/rule_context.dart';
import 'package:analyzer/analysis_rule/rule_visitor_registry.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/ast/token.dart';
import 'package:analyzer/dart/ast/visitor.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/error/error.dart';

import '../analyzer.dart';
import '../diagnostic.dart' as diag;
import '../extensions.dart';

const _desc = r"Don't override fields.";

class OverriddenFields extends AnalysisRule {
  new() : super(name: LintNames.overridden_fields, description: _desc);

  @override
  DiagnosticCode get diagnosticCode => diag.overriddenFields;

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

class _Visitor(final AnalysisRule rule) extends SimpleAstVisitor<void> {
  @override
  void visitFieldDeclaration(FieldDeclaration node) {
    if (node.isAugmentation) return;
    if (node.isStatic) return;

    for (var variable in node.fields.variables) {
      if (variable.declaredFragment?.element case FieldElement element) {
        _checkField(element, variable.name);
      }
    }
  }

  @override
  void visitPrimaryConstructorDeclaration(PrimaryConstructorDeclaration node) {
    for (var parameter in node.formalParameters.parameters) {
      if (parameter is! FieldFormalParameter) {
        var element = parameter.declaredFragment?.element;
        if (element is FieldFormalParameterElement) {
          var fieldElement = element.field;
          var name = parameter.name;
          if (fieldElement != null && name != null) {
            _checkField(fieldElement, name);
          }
        }
      }
    }
  }

  void _checkField(FieldElement element, Token nameToken) {
    var parent = element.enclosingElement;
    if (parent is InterfaceElement) {
      var overriddenMember = parent.getInheritedConcreteMember(
        Name(parent.library.uri, nameToken.lexeme),
      );
      if (overriddenMember is GetterElement &&
          overriddenMember.isOriginVariable) {
        var definingInterface = overriddenMember.enclosingElement;
        rule.reportAtToken(
          nameToken,
          arguments: [definingInterface.displayName],
        );
      }
    }
  }
}