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Add 'Extract local variable' fix for UNCHECKED_PROPERTY_ACCESS_OF_NULLABLE_VALUE.
Bug: #47588 Change-Id: Ice823f239b3b152d9583cecb143ea78a62361539 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/227900 Reviewed-by: Samuel Rawlins <[email protected]> Reviewed-by: Phil Quitslund <[email protected]> Commit-Queue: Konstantin Shcheglov <[email protected]>
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‎pkg/analysis_server/lib/src/services/correction/dart/extract_local_variable.dart

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// Copyright (c) 2022, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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import 'package:analysis_server/src/services/correction/dart/abstract_producer.dart';
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import 'package:analysis_server/src/services/correction/fix.dart';
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import 'package:analysis_server/src/services/correction/util.dart';
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import 'package:analyzer/dart/ast/ast.dart';
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import 'package:analyzer/dart/ast/token.dart';
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import 'package:analyzer/dart/ast/visitor.dart';
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import 'package:analyzer/dart/element/element.dart';
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import 'package:analyzer/source/source_range.dart';
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import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
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import 'package:analyzer_plugin/utilities/fixes/fixes.dart';
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import 'package:analyzer_plugin/utilities/range_factory.dart';
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class ExtractLocalVariable extends CorrectionProducer {
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@override
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FixKind get fixKind => DartFixKind.EXTRACT_LOCAL_VARIABLE;
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@override
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Future<void> compute(ChangeBuilder builder) async {
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final node = this.node;
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if (node is! SimpleIdentifier) {
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return;
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}
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var parent = node.parent;
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if (parent is MethodInvocation && parent.methodName == node) {
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await _rewrite(
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builder: builder,
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target: parent.target,
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);
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}
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if (parent is PrefixedIdentifier && parent.identifier == node) {
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await _rewrite(
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builder: builder,
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target: parent.prefix,
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);
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}
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if (parent is PropertyAccess && parent.propertyName == node) {
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await _rewrite(
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builder: builder,
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target: parent.target,
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);
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}
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}
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Future<void> _rewrite({
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required ChangeBuilder builder,
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required Expression? target,
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}) async {
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if (target is PrefixedIdentifier) {
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await _rewriteProperty(
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builder: builder,
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target: target,
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targetProperty: target.staticElement,
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);
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}
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if (target is PropertyAccess) {
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await _rewriteProperty(
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builder: builder,
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target: target,
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targetProperty: target.propertyName.staticElement,
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);
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}
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if (target is SimpleIdentifier) {
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await _rewriteProperty(
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builder: builder,
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target: target,
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targetProperty: target.staticElement,
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);
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}
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}
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Future<void> _rewriteProperty({
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required ChangeBuilder builder,
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required Expression target,
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required Element? targetProperty,
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}) async {
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if (targetProperty is PropertyAccessorElement &&
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targetProperty.isGetter &&
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typeSystem.isPotentiallyNullable(targetProperty.returnType)) {
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AstNode? enclosingNode = target;
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while (true) {
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if (enclosingNode == null || enclosingNode is FunctionBody) {
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return;
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}
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if (enclosingNode is IfStatement) {
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var condition = enclosingNode.condition;
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if (condition is BinaryExpression &&
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condition.rightOperand is NullLiteral &&
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condition.operator.type == TokenType.BANG_EQ) {
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var encoder = _ExpressionEncoder();
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var leftCode = encoder.encode(condition.leftOperand);
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var targetCode = encoder.encode(target);
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if (leftCode == targetCode) {
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var occurrences = <SourceRange>[];
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enclosingNode.accept(
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_OccurrencesVisitor(encoder, occurrences, leftCode),
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);
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var ifOffset = enclosingNode.offset;
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var ifLineOffset = utils.getLineContentStart(ifOffset);
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var prefix = utils.getLinePrefix(ifOffset);
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var initializerCode = utils.getNodeText(target);
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if (target is SimpleIdentifier) {
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initializerCode = 'this.$initializerCode';
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}
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await builder.addDartFileEdit(file, (builder) {
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var propertyName = targetProperty.name;
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builder.addInsertion(ifLineOffset, (builder) {
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builder.write(prefix);
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builder.writeln('final $propertyName = $initializerCode;');
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});
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for (var occurrence in occurrences) {
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builder.addSimpleReplacement(occurrence, propertyName);
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}
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});
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return;
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}
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}
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break;
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}
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enclosingNode = enclosingNode.parent;
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}
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}
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}
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/// Return an instance of this class. Used as a tear-off in `FixProcessor`.
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static ExtractLocalVariable newInstance() => ExtractLocalVariable();
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}
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class _ExpressionEncoder {
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final Map<Element, int> _elementIds = {};
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String encode(Expression node) {
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var tokens = TokenUtils.getNodeTokens(node);
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var tokenToElementMap = Map<Token, Element>.identity();
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node.accept(
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_FunctionAstVisitor(
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simpleIdentifier: (node) {
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var element = node.staticElement;
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if (element != null) {
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tokenToElementMap[node.token] = element;
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}
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},
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),
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);
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var tokensWithId = tokens.map((token) {
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var tokenString = token.lexeme;
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var element = tokenToElementMap[token];
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if (element != null) {
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var elementId = _elementIds.putIfAbsent(
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element,
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() => _elementIds.length,
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);
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tokenString += '#$elementId';
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}
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return tokenString;
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});
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const separator = '\uFFFF';
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return tokensWithId.join(separator) + separator;
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}
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}
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/// [RecursiveAstVisitor] that delegates visit methods to functions.
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class _FunctionAstVisitor extends RecursiveAstVisitor<void> {
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final void Function(SimpleIdentifier)? simpleIdentifier;
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_FunctionAstVisitor({
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this.simpleIdentifier,
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});
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@override
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void visitSimpleIdentifier(SimpleIdentifier node) {
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if (simpleIdentifier != null) {
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simpleIdentifier!(node);
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}
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super.visitSimpleIdentifier(node);
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}
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}
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class _OccurrencesVisitor extends GeneralizingAstVisitor<void> {
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final _ExpressionEncoder encoder;
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final List<SourceRange> occurrences;
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final String searchCode;
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_OccurrencesVisitor(this.encoder, this.occurrences, this.searchCode);
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@override
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void visitExpression(Expression node) {
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var nodeCode = encoder.encode(node);
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if (nodeCode == searchCode) {
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occurrences.add(range.node(node));
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}
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super.visitExpression(node);
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}
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}

‎pkg/analysis_server/lib/src/services/correction/fix.dart

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@@ -635,6 +635,11 @@ class DartFixKind {
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DartFixKindPriority.DEFAULT,
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"Extend the class '{0}'",
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);
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static const EXTRACT_LOCAL_VARIABLE = FixKind(
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'dart.fix.extractLocalVariable',
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DartFixKindPriority.DEFAULT,
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'Extract local variable',
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);
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static const IGNORE_ERROR_LINE = FixKind(
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'dart.fix.ignore.line',
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DartFixKindPriority.IGNORE,

‎pkg/analysis_server/lib/src/services/correction/fix_internal.dart

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@@ -80,6 +80,7 @@ import 'package:analysis_server/src/services/correction/dart/create_no_such_meth
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import 'package:analysis_server/src/services/correction/dart/create_setter.dart';
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import 'package:analysis_server/src/services/correction/dart/data_driven.dart';
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import 'package:analysis_server/src/services/correction/dart/extend_class_for_mixin.dart';
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import 'package:analysis_server/src/services/correction/dart/extract_local_variable.dart';
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import 'package:analysis_server/src/services/correction/dart/flutter_remove_widget.dart';
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import 'package:analysis_server/src/services/correction/dart/ignore_diagnostic.dart';
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import 'package:analysis_server/src/services/correction/dart/import_library.dart';
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],
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CompileTimeErrorCode.UNCHECKED_METHOD_INVOCATION_OF_NULLABLE_VALUE: [
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AddNullCheck.newInstance,
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ExtractLocalVariable.newInstance,
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ReplaceWithNullAware.single,
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],
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CompileTimeErrorCode.UNCHECKED_OPERATOR_INVOCATION_OF_NULLABLE_VALUE: [
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AddNullCheck.newInstance,
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],
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CompileTimeErrorCode.UNCHECKED_PROPERTY_ACCESS_OF_NULLABLE_VALUE: [
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AddNullCheck.newInstance,
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ExtractLocalVariable.newInstance,
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ReplaceWithNullAware.single,
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],
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CompileTimeErrorCode.UNCHECKED_USE_OF_NULLABLE_VALUE_AS_CONDITION: [

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