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// 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:analysis_server/src/services/correction/dart/abstract_producer.dart';
import 'package:analysis_server/src/services/correction/fix.dart';
import 'package:analyzer/dart/ast/ast.dart';
import 'package:analyzer/dart/ast/token.dart';
import 'package:analyzer/dart/element/element.dart';
import 'package:analyzer/source/source_range.dart';
import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
import 'package:analyzer_plugin/utilities/range_factory.dart';
class RemoveDeadIfNull extends CorrectionProducer {
@override
FixKind get fixKind => DartFixKind.REMOVE_IF_NULL_OPERATOR;
@override
Future<void> compute(ChangeBuilder builder) async {
var sourceRange = findIfNull();
if (sourceRange == null) {
return;
}
await builder.addDartFileEdit(file, (builder) {
builder.addDeletion(sourceRange);
});
}
/// Finds the dead if-null expression above [node].
SourceRange findIfNull() {
var child = node;
var parent = node.parent;
while (parent != null) {
if (parent is BinaryExpression &&
parent.operator.type == TokenType.QUESTION_QUESTION &&
parent.rightOperand == child) {
return range.endEnd(parent.leftOperand, parent.rightOperand);
}
if (parent is AssignmentExpression &&
parent.operator.type == TokenType.QUESTION_QUESTION_EQ &&
parent.rightHandSide == child) {
var assignee = parent.leftHandSide;
if (parent.parent is ExpressionStatement &&
assignee is SimpleIdentifier &&
assignee.staticElement is PromotableElement) {
return utils.getLinesRange(range.node(parent.parent));
} else {
return range.endEnd(parent.leftHandSide, parent.rightHandSide);
}
}
child = parent;
parent = parent.parent;
}
return null;
}
/// Returns an instance of this class. Used as a tear-off in `FixProcessor`.
static RemoveDeadIfNull newInstance() => RemoveDeadIfNull();
}