DeCo. Build fields from primary constructor formal parameters.

Introduce element building for `PrimaryConstructorDeclaration` that synthesizes a backing field and a matching field-formal parameter when a primary constructor parameter is declared with `final` or `var`. The constructor fragment is created, `const` is honored, and child fragments for such parameters are added as synthetic fields. Track the relationship between the declaring formal and the created fragments in `Linker.declaringFormalParameters` via a new `DeclaringFormalParameterInfo`. Subsequent visits to the same parameter reuse these fragments (including for default-parameter wrappers), which avoids duplicates and keeps the element model consistent. Propagate explicit types from declaring formals to the synthesized fields so that explicitly typed or function-typed parameters produce correctly typed fields (`_copyDeclaringFormalParametersExplicitTypes`). Traverse `NameWithTypeParameters` in the declaring-constructors path to pick up type parameters, and add convenience accessors `finalKeyword`/`varKeyword` plus a `hasFinalOrVarKeyword` helper on formal parameters. Some changes to extension type offsets, to align better with new AST presentation. Bug: #61701 Change-Id: Icbd507b4304131df6bce47e1a5eb5fe6f144dbd3 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/459160 Commit-Queue: Konstantin Shcheglov <scheglov@google.com> Reviewed-by: Johnni Winther <johnniwinther@google.com>

Author: scheglov

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

@@ -109,7 +109,7 @@ testFineAfterLibraryAnalyzerHook;
 // TODO(scheglov): Clean up the list of implicitly analyzed files.
 class AnalysisDriver {
  /// The version of data format, should be incremented on every format change.
- static const int DATA_VERSION = 581;
+ static const int DATA_VERSION = 582;
 
  /// The number of exception contexts allowed to write. Once this field is
  /// zero, we stop writing any new exception contexts in this process.

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

@@ -12259,6 +12259,14 @@ final class FunctionTypedFormalParameterImpl extends NormalFormalParameterImpl
  return parameters.endToken;
  }
 
+ /// If [keyword] is `final`, returns it.
+ Token? get finalKeyword {
+ if (keyword?.keyword == Keyword.FINAL) {
+ return keyword;
+ }
+ return null;
+ }
+
  @generated
  @override
  Token get firstTokenAfterCommentAndMetadata {
@@ -12284,7 +12292,7 @@ final class FunctionTypedFormalParameterImpl extends NormalFormalParameterImpl
  bool get isExplicitlyTyped => true;
 
  @override
- bool get isFinal => false;
+ bool get isFinal => keyword?.keyword == Keyword.FINAL;
 
  @generated
  @override
@@ -12317,6 +12325,14 @@ final class FunctionTypedFormalParameterImpl extends NormalFormalParameterImpl
  _typeParameters = _becomeParentOf(typeParameters);
  }
 
+ /// If [keyword] is `var`, returns it.
+ Token? get varKeyword {
+ if (keyword?.keyword == Keyword.VAR) {
+ return keyword;
+ }
+ return null;
+ }
+
  @generated
  @override
  ChildEntities get _childEntities => super._childEntities
@@ -22211,6 +22227,14 @@ final class SimpleFormalParameterImpl extends NormalFormalParameterImpl
  throw StateError('Expected at least one non-null');
  }
 
+ /// If [keyword] is `final`, returns it.
+ Token? get finalKeyword {
+ if (keyword?.keyword == Keyword.FINAL) {
+ return keyword;
+ }
+ return null;
+ }
+
  @generated
  @override
  Token get firstTokenAfterCommentAndMetadata {
@@ -22250,6 +22274,14 @@ final class SimpleFormalParameterImpl extends NormalFormalParameterImpl
  _type = _becomeParentOf(type);
  }
 
+ /// If [keyword] is `var`, returns it.
+ Token? get varKeyword {
+ if (keyword?.keyword == Keyword.VAR) {
+ return keyword;
+ }
+ return null;
+ }
+
  @generated
  @override
  ChildEntities get _childEntities => super._childEntities

pkg/analyzer/lib/src/summary2/element_builder.dart

@@ -1067,7 +1067,7 @@ class FragmentBuilder extends ThrowingAstVisitor<void> {
  var holder = _EnclosingContext(fragment: fragment);
  _withEnclosing(holder, () {
  if (useDeclaringConstructorsAst) {
- node.namePart.typeParameters?.accept(this);
+ node.namePart.accept(this);
  node.body.accept(this);
  } else {
  node.typeParameters?.accept(this);
@@ -1603,11 +1603,16 @@ class FragmentBuilder extends ThrowingAstVisitor<void> {
  var nameToken = node.name;
  var name2 = _getFragmentName(nameToken);
 
- var fragment = FormalParameterFragmentImpl(
- name: name2,
- nameOffset: null,
- parameterKind: node.kind,
- );
+ FormalParameterFragmentImpl fragment;
+ if (_linker.getDeclaringFormalInfo(node) case var declaring?) {
+ fragment = declaring.formalFragment;
+ } else {
+ fragment = FormalParameterFragmentImpl(
+ name: name2,
+ nameOffset: null,
+ parameterKind: node.kind,
+ );
+ }
  _linker.elementNodes[fragment] = node;
  _enclosingContext.addParameter(fragment);
 
@@ -1795,6 +1800,11 @@ class FragmentBuilder extends ThrowingAstVisitor<void> {
  node.typeArguments?.accept(this);
  }
 
+ @override
+ void visitNameWithTypeParameters(NameWithTypeParameters node) {
+ node.typeParameters?.accept(this);
+ }
+
  @override
  void visitPartDirective(covariant PartDirectiveImpl node) {
  var index = _partDirectiveIndex++;
@@ -1806,6 +1816,55 @@ class FragmentBuilder extends ThrowingAstVisitor<void> {
  @override
  void visitPartOfDirective(PartOfDirective node) {}
 
+ @override
+ void visitPrimaryConstructorDeclaration(
+ covariant PrimaryConstructorDeclarationImpl node,
+ ) {
+ node.typeParameters?.accept(this);
+
+ var fragmentName = 'new';
+ if (node.constructorName?.name case var nameToken?) {
+ fragmentName = _getFragmentName(nameToken) ?? 'new';
+ }
+
+ var fragment = ConstructorFragmentImpl(name: fragmentName);
+ fragment.isConst = node.constKeyword != null;
+ fragment.typeName = node.typeName.lexeme;
+ _linker.elementNodes[fragment] = node;
+
+ _addChildFragment(fragment);
+
+ // Handle declaring formal parameters.
+ for (var formalParameter in node.formalParameters.parameters) {
+ if (formalParameter.hasFinalOrVarKeyword) {
+ var name = _getFragmentName(formalParameter.name);
+ var fieldFragment = FieldFragmentImpl(name: name);
+ fieldFragment.isFinal = formalParameter.isFinal;
+ fieldFragment.isSynthetic = true;
+ _linker.elementNodes[fieldFragment] = formalParameter;
+ _addChildFragment(fieldFragment);
+
+ var formalFragment = FieldFormalParameterFragmentImpl(
+ name: name,
+ nameOffset: null,
+ parameterKind: formalParameter.kind,
+ );
+
+ _linker.declaringFormalParameters[formalParameter] =
+ DeclaringFormalParameterInfo(
+ node: formalParameter,
+ fieldFragment: fieldFragment,
+ formalFragment: formalFragment,
+ );
+ }
+ }
+
+ _buildExecutableElementChildren(
+ fragment: fragment,
+ formalParameters: node.formalParameters,
+ );
+ }
+
  @override
  void visitRecordTypeAnnotation(RecordTypeAnnotation node) {
  node.positionalFields.accept(this);
@@ -1838,11 +1897,16 @@ class FragmentBuilder extends ThrowingAstVisitor<void> {
  var nameToken = node.name;
  var name2 = _getFragmentName(nameToken);
 
- var fragment = FormalParameterFragmentImpl(
- name: name2,
- nameOffset: null,
- parameterKind: node.kind,
- );
+ FormalParameterFragmentImpl fragment;
+ if (_linker.getDeclaringFormalInfo(node) case var declaring?) {
+ fragment = declaring.formalFragment;
+ } else {
+ fragment = FormalParameterFragmentImpl(
+ name: name2,
+ nameOffset: null,
+ parameterKind: node.kind,
+ );
+ }
  _linker.elementNodes[fragment] = node;
  _enclosingContext.addParameter(fragment);
 
@@ -2131,3 +2195,30 @@ class _EnclosingContext {
  typeParameters.add(fragment);
  }
 }
+
+extension _FormalParameterImplExtension on FormalParameterImpl {
+ bool get hasFinalOrVarKeyword {
+ switch (this) {
+ case DefaultFormalParameterImpl self:
+ return self.parameter.hasFinalOrVarKeyword;
+ case FunctionTypedFormalParameterImpl self:
+ return self.finalKeyword != null || self.varKeyword != null;
+ case SimpleFormalParameterImpl self:
+ return self.finalKeyword != null || self.varKeyword != null;
+ default:
+ return false;
+ }
+ }
+
+ FormalParameterImpl get selfOrParentDefault {
+ return parent.ifTypeOrNull<DefaultFormalParameterImpl>() ?? this;
+ }
+}
+
+extension _LinkerExtension on Linker {
+ DeclaringFormalParameterInfo? getDeclaringFormalInfo(
+ FormalParameterImpl node,
+ ) {
+ return declaringFormalParameters[node.selfOrParentDefault];
+ }
+}