DeCo. AST for construtors with 'new' and 'factory'.

Change-Id: I84c08de3fb6fe1479a23f7504b9ac340454a8402
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/463501
Reviewed-by: Brian Wilkerson <[email protected]>
Reviewed-by: Paul Berry <[email protected]>
Commit-Queue: Konstantin Shcheglov <[email protected]>

Author: scheglov

pkg/analyzer/api.txt

@@ -970,10 +970,11 @@ package:analyzer/dart/ast/ast.dart:
     factoryKeyword (getter: Token?)
     initializers (getter: NodeList<ConstructorInitializer>)
     name (getter: Token?)
+    newKeyword (getter: Token?)
     parameters (getter: FormalParameterList)
     period (getter: Token?)
     redirectedConstructor (getter: ConstructorName?)
-    returnType (getter: Identifier)
+    returnType (getter: Identifier, deprecated)
     separator (getter: Token?)
     typeName (getter: SimpleIdentifier?)
   ConstructorFieldInitializer (class extends Object implements ConstructorInitializer):

pkg/analyzer/lib/src/dart/analysis/index.dart

@@ -810,8 +810,10 @@ class _IndexContributor extends GeneralizingAstVisitor {
       var element = node.declaredFragment!.element;
       var superConstructor = element.superConstructor;
       if (superConstructor != null) {
-        var offset = node.returnType.offset;
-        var end = (node.name ?? node.returnType).end;
+        // TODO(scheglov): https://github.com/dart-lang/sdk/issues/62067
+        var offset = node.typeName!.offset;
+        // TODO(scheglov): https://github.com/dart-lang/sdk/issues/62067
+        var end = (node.name ?? node.typeName!).end;
         recordRelationOffset(
           superConstructor,
           IndexRelationKind.IS_INVOKED_BY,

pkg/analyzer/lib/src/dart/analysis/referenced_names.dart

@@ -343,7 +343,7 @@ class _ReferencedNamesComputer extends GeneralizingAstVisitor<void> {
     }
     // Ignore class names references from constructors.
     var parent = node.parent!;
-    if (parent is ConstructorDeclaration && parent.returnType == node) {
+    if (parent is ConstructorDeclaration && parent.typeName == node) {
       return;
     }
     // Prepare name.

pkg/analyzer/lib/src/dart/analysis/results.dart

@@ -93,7 +93,7 @@ class DeclarationByElementLocator extends UnifyingAstVisitor<void> {
             result = node;
           }
         } else {
-          if (_hasOffset(node.returnType)) {
+          if (_hasOffset(node.typeName)) {
             result = node;
           }
         }

pkg/analyzer/lib/src/dart/ast/ast.dart

@@ -4713,6 +4713,11 @@ abstract final class ConstructorDeclaration implements ClassMember {
   /// is unnamed.
   Token? get name;
 
+  /// The token for the `new` keyword, or `null` if the keyword is absent, so
+  /// either [factoryKeyword] is not `null`, or the old syntax with [typeName]
+  /// is used.
+  Token? get newKeyword;
+
   /// The parameters associated with the constructor.
   FormalParameterList get parameters;
 
@@ -4725,6 +4730,7 @@ abstract final class ConstructorDeclaration implements ClassMember {
   ConstructorName? get redirectedConstructor;
 
   /// The type of object being created.
+  @Deprecated('Use typeName instead')
   Identifier get returnType;
 
   /// The token for the separator (colon or equals) before the initializer list
@@ -4734,7 +4740,7 @@ abstract final class ConstructorDeclaration implements ClassMember {
 
   /// The name of the enclosing type, e.g. `C` in `C() {}` or `C.named() {}`.
   ///
-  /// Or `null` if uses new syntax with `newKeyword` or [factoryKeyword].
+  /// Or `null` if uses new syntax with [newKeyword] or [factoryKeyword].
   SimpleIdentifier? get typeName;
 }
 
@@ -4744,7 +4750,8 @@ abstract final class ConstructorDeclaration implements ClassMember {
     GenerateNodeProperty('externalKeyword', tokenGroupId: 0),
     GenerateNodeProperty('constKeyword', tokenGroupId: 0, isTokenFinal: false),
     GenerateNodeProperty('factoryKeyword', tokenGroupId: 0),
-    GenerateNodeProperty('returnType'),
+    GenerateNodeProperty('newKeyword', tokenGroupId: 0),
+    GenerateNodeProperty('typeName'),
     GenerateNodeProperty('period'),
     GenerateNodeProperty('name'),
     GenerateNodeProperty('parameters'),
@@ -4773,7 +4780,11 @@ final class ConstructorDeclarationImpl extends ClassMemberImpl
   final Token? factoryKeyword;
 
   @generated
-  IdentifierImpl _returnType;
+  @override
+  final Token? newKeyword;
+
+  @generated
+  SimpleIdentifierImpl? _typeName;
 
   @generated
   @override
@@ -4812,19 +4823,20 @@ final class ConstructorDeclarationImpl extends ClassMemberImpl
     required this.externalKeyword,
     required this.constKeyword,
     required this.factoryKeyword,
-    required IdentifierImpl returnType,
+    required this.newKeyword,
+    required SimpleIdentifierImpl? typeName,
     required this.period,
     required this.name,
     required FormalParameterListImpl parameters,
     required this.separator,
     required List<ConstructorInitializerImpl> initializers,
     required ConstructorNameImpl? redirectedConstructor,
     required FunctionBodyImpl body,
-  }) : _returnType = returnType,
+  }) : _typeName = typeName,
        _parameters = parameters,
        _redirectedConstructor = redirectedConstructor,
        _body = body {
-    _becomeParentOf(returnType);
+    _becomeParentOf(typeName);
     _becomeParentOf(parameters);
     this.initializers._initialize(this, initializers);
     _becomeParentOf(redirectedConstructor);
@@ -4854,11 +4866,21 @@ final class ConstructorDeclarationImpl extends ClassMemberImpl
           externalKeyword,
           constKeyword,
           factoryKeyword,
+          newKeyword,
         )
         case var result?) {
       return result;
     }
-    return returnType.beginToken;
+    if (typeName case var typeName?) {
+      return typeName.beginToken;
+    }
+    if (period case var period?) {
+      return period;
+    }
+    if (name case var name?) {
+      return name;
+    }
+    return parameters.beginToken;
   }
 
   /// Whether this is a trivial constructor.
@@ -4891,27 +4913,31 @@ final class ConstructorDeclarationImpl extends ClassMemberImpl
     _redirectedConstructor = _becomeParentOf(redirectedConstructor);
   }
 
+  @Deprecated('Use typeName instead')
+  @override
+  IdentifierImpl get returnType {
+    // TODO(scheglov): https://github.com/dart-lang/sdk/issues/62067
+    return typeName!;
+  }
+
   @generated
   @override
-  IdentifierImpl get returnType => _returnType;
+  SimpleIdentifierImpl? get typeName => _typeName;
 
   @generated
-  set returnType(IdentifierImpl returnType) {
-    _returnType = _becomeParentOf(returnType);
+  set typeName(SimpleIdentifierImpl? typeName) {
+    _typeName = _becomeParentOf(typeName);
   }
 
-  @override
-  // TODO(scheglov): flip the implementation to make this property leading
-  SimpleIdentifierImpl? get typeName => returnType as SimpleIdentifierImpl;
-
   @generated
   @override
   ChildEntities get _childEntities => super._childEntities
     ..addToken('augmentKeyword', augmentKeyword)
     ..addToken('externalKeyword', externalKeyword)
     ..addToken('constKeyword', constKeyword)
     ..addToken('factoryKeyword', factoryKeyword)
-    ..addNode('returnType', returnType)
+    ..addToken('newKeyword', newKeyword)
+    ..addNode('typeName', typeName)
     ..addToken('period', period)
     ..addToken('name', name)
     ..addNode('parameters', parameters)
@@ -4929,7 +4955,7 @@ final class ConstructorDeclarationImpl extends ClassMemberImpl
   @override
   void visitChildren(AstVisitor visitor) {
     super.visitChildren(visitor);
-    returnType.accept(visitor);
+    typeName?.accept(visitor);
     parameters.accept(visitor);
     initializers.accept(visitor);
     redirectedConstructor?.accept(visitor);
@@ -4942,8 +4968,10 @@ final class ConstructorDeclarationImpl extends ClassMemberImpl
     if (super._childContainingRange(rangeOffset, rangeEnd) case var result?) {
       return result;
     }
-    if (returnType._containsOffset(rangeOffset, rangeEnd)) {
-      return returnType;
+    if (typeName case var typeName?) {
+      if (typeName._containsOffset(rangeOffset, rangeEnd)) {
+        return typeName;
+      }
     }
     if (parameters._containsOffset(rangeOffset, rangeEnd)) {
       return parameters;

pkg/analyzer/lib/src/dart/ast/element_locator.dart

@@ -166,7 +166,7 @@ class _ElementMapper2 extends GeneralizingAstVisitor<Element> {
       }
     } else if (parent is ConstructorDeclaration) {
       // Map a constructor declarations to its associated constructor element.
-      var returnType = parent.returnType;
+      var returnType = parent.typeName;
       if (identical(returnType, node)) {
         var name = parent.name;
         if (name != null) {

pkg/analyzer/lib/src/dart/ast/extensions.dart

@@ -100,8 +100,10 @@ extension ConstructorDeclarationExtension on ConstructorDeclaration {
   /// declaration, accounting for named and unnamed constructors.
   SourceRange get errorRange {
     var name = this.name;
-    var offset = returnType.offset;
-    int length = (name != null ? name.end : returnType.end) - offset;
+    // TODO(scheglov): https://github.com/dart-lang/sdk/issues/62067
+    var offset = typeName!.offset;
+    // TODO(scheglov): https://github.com/dart-lang/sdk/issues/62067
+    int length = (name != null ? name.end : typeName!.end) - offset;
     return SourceRange(offset, length);
   }
 

pkg/analyzer/lib/src/dart/ast/to_source_visitor.dart

@@ -265,7 +265,7 @@ class ToSourceVisitor implements AstVisitor<void> {
     _visitToken(node.externalKeyword, suffix: ' ');
     _visitToken(node.constKeyword, suffix: ' ');
     _visitToken(node.factoryKeyword, suffix: ' ');
-    _visitNode(node.returnType);
+    _visitNode(node.typeName);
     _visitToken(node.name, prefix: '.');
     _visitNode(node.parameters);
     _visitNodeList(node.initializers, prefix: ' : ', separator: ', ');

pkg/analyzer/lib/src/dart/ast/utilities.dart

@@ -80,7 +80,8 @@ class NodeLocator2 extends UnifyingAstVisitor<void> {
     // Names do not have AstNodes but offsets at the end should be treated as
     // part of the declaration (not parameter list).
     if (_startOffset == _endOffset &&
-        _startOffset == (node.name ?? node.returnType).end) {
+        // TODO(scheglov): https://github.com/dart-lang/sdk/issues/62067
+        _startOffset == (node.name ?? node.typeName!).end) {
       _foundNode = node;
       return;
     }
@@ -456,10 +457,7 @@ class NodeReplacer extends ThrowingAstVisitor<bool> {
 
   @override
   bool visitConstructorDeclaration(covariant ConstructorDeclarationImpl node) {
-    if (identical(node.returnType, _oldNode)) {
-      node.returnType = _newNode as IdentifierImpl;
-      return true;
-    } else if (identical(node.parameters, _oldNode)) {
+    if (identical(node.parameters, _oldNode)) {
       node.parameters = _newNode as FormalParameterListImpl;
       return true;
     } else if (identical(node.redirectedConstructor, _oldNode)) {

pkg/analyzer/lib/src/dart/constant/constant_verifier.dart

@@ -168,7 +168,8 @@ class ConstantVerifier extends RecursiveAstVisitor<void> {
       var element = node.declaredFragment!.element;
       if (!element.isCycleFree && !element.isFactory) {
         _diagnosticReporter.atNode(
-          node.returnType,
+          // TODO(scheglov): https://github.com/dart-lang/sdk/issues/62067
+          node.typeName!,
           diag.recursiveConstantConstructor,
         );
       }