[cfe] Make VariableBase.context independent from VariableBase.parent

Previously the getter VariableBase.context was redirecting to
VariableBase.parent, effectively requiring a change of the ownership
over the variable. This CL makes VariableBase.context a field of
VariableBase, allowing for the previously existing ownership structure
of the AST tree nodes.

The change allows to avoid workarounds for the existing
ownership-restoring logic, such as the assignments to the `parent`
pointer made in the constructors of the AST nodes and their
`transformChildren` and `transformOrRemoveChildren` methods.

Part of https://github.com/dart-lang/sdk/issues/61572

Change-Id: I307c9d2b23c8201f8d7d2a100acf9fb8f3af2572
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/494441
Commit-Queue: Chloe Stefantsova <cstefantsova@google.com>
Reviewed-by: Johnni Winther <johnniwinther@google.com>

pkg/front_end/lib/src/builder/formal_parameter_builder.dart

@@ -292,11 +292,11 @@ class FormalParameterBuilder extends NamedBuilderImpl
         )..fileOffset = fileOffset;
       }
     }
-    return _variable!.asExpressionVariable;
+    return _variable!.asVariableDeclaration;
   }
 
   @override
-  VariableDeclaration get variable => _variable!.asExpressionVariable;
+  VariableDeclaration get variable => _variable!.asVariableDeclaration;
 
   @override
   void onInferredType(DartType type) {
@@ -592,7 +592,7 @@ class CatchParameterBuilder extends NamedBuilderImpl
   String get fullNameForErrors => name;
 
   @override
-  VariableDeclaration get variable => _variable!.asExpressionVariable;
+  VariableDeclaration get variable => _variable!.asVariableDeclaration;
 
   @override
   VariableDeclaration build(SourceLibraryBuilder library) {
@@ -630,7 +630,7 @@ class CatchParameterBuilder extends NamedBuilderImpl
         )..fileOffset = fileOffset;
       }
     }
-    return _variable!.asExpressionVariable;
+    return _variable!.asVariableDeclaration;
   }
 
   @override

pkg/front_end/lib/src/kernel/body_builder.dart

@@ -3413,7 +3413,7 @@ class BodyBuilderImpl extends StackListenerImpl
         isImplicitlyTyped: currentLocalVariableType == null,
       );
       variableInitialization = new VariableInitialization(
-        variable: internalVariable.asExpressionVariable,
+        variable: internalVariable.asVariableDeclaration,
         initializer: initializer,
         hasDeclaredInitializer: initializer != null,
       );

pkg/front_end/lib/src/kernel/internal_ast.dart

@@ -1165,13 +1165,13 @@ class InternalPositionalParameter extends TreeNode
   });
 
   @override
-  // TODO(62620): Conforming to [VariableInitialization] interface. Remove this.
+  // TODO(62620): Conforming to [VariableDeclaration] interface. Remove this.
   List<VariableContext>? get capturedContexts {
     throw new UnsupportedError("${this.runtimeType}.capturedContexts");
   }
 
   @override
-  // TODO(62620): Conforming to [VariableInitialization] interface. Remove this.
+  // TODO(62620): Conforming to [VariableDeclaration] interface. Remove this.
   void set capturedContexts(List<VariableContext>? value) {
     throw new UnsupportedError("${this.runtimeType}.capturedContexts=");
   }
@@ -1268,13 +1268,13 @@ class InternalNamedParameter extends TreeNode
   });
 
   @override
-  // TODO(62620): Conforming to [VariableInitialization] interface. Remove this.
+  // TODO(62620): Conforming to [VariableDeclaration] interface. Remove this.
   List<VariableContext>? get capturedContexts {
     throw new UnsupportedError("${this.runtimeType}.capturedContexts");
   }
 
   @override
-  // TODO(62620): Conforming to [VariableInitialization] interface. Remove this.
+  // TODO(62620): Conforming to [VariableDeclaration] interface. Remove this.
   void set capturedContexts(List<VariableContext>? value) {
     throw new UnsupportedError("${this.runtimeType}.capturedContexts=");
   }
@@ -1718,6 +1718,7 @@ mixin DelegatingVariableMixin on InternalVariableMixin
   }
 
   @override
+  // Coverage-ignore(suite): Not run.
   R accept1<R, A>(StatementVisitor1<R, A> v, A arg) {
     return astVariable.accept1(v, arg);
   }
@@ -1729,8 +1730,14 @@ mixin DelegatingVariableMixin on InternalVariableMixin
     astVariable.cosmeticName = value;
   }
 
-  VariableContext get context {
-    throw new UnsupportedError("${this.runtimeType}");
+  @override
+  // Coverage-ignore(suite): Not run.
+  VariableContext get context => astVariable.context;
+
+  @override
+  // Coverage-ignore(suite): Not run.
+  void set context(VariableContext value) {
+    astVariable.context = value;
   }
 
   @override
@@ -1937,7 +1944,7 @@ mixin InternalVariableMixin on TreeNode implements InternalVariable {
   String? lateName;
 
   @override
-  VariableDeclaration get asExpressionVariable => this as VariableDeclaration;
+  VariableDeclaration get asVariableDeclaration => this as VariableDeclaration;
 }
 
 /// Front end specific implementation of [LoadLibrary].

pkg/front_end/lib/src/type_inference/inference_visitor.dart

@@ -13242,6 +13242,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
           exceptionCatchVariable,
           captureKind: _captureKindForVariable(exceptionCatchVariable),
         );
+        node.exception = exceptionCatchVariable;
       }
       if (node.stackTrace case CatchVariable stackTraceCatchVariable?) {
         // TODO(62401): Remove the casts when the flow analysis uses
@@ -13253,6 +13254,7 @@ class InferenceVisitorImpl extends InferenceVisitorBase
           stackTraceCatchVariable,
           captureKind: _captureKindForVariable(stackTraceCatchVariable),
         );
+        node.stackTrace = stackTraceCatchVariable;
       }
     }
     StatementInferenceResult bodyResult = inferStatement(node.body);

pkg/kernel/lib/src/ast/statements.dart

@@ -1593,13 +1593,13 @@ class VariableStatement extends Statement
   }
 
   @override
-  // TODO(62620): Conforming to [VariableInitialization] interface. Remove this.
+  // TODO(62620): Conforming to [VariableDeclaration] interface. Remove this.
   List<VariableContext>? get capturedContexts {
     throw new UnsupportedError("${this.runtimeType}.capturedContexts");
   }
 
   @override
-  // TODO(62620): Conforming to [VariableInitialization] interface. Remove this.
+  // TODO(62620): Conforming to [VariableDeclaration] interface. Remove this.
   void set capturedContexts(List<VariableContext>? value) {
     throw new UnsupportedError("${this.runtimeType}.capturedContexts=");
   }
@@ -1890,28 +1890,33 @@ class VariableStatement extends Statement
 
   @override
   VariableDeclaration? get variableInitialization {
-    throw new UnsupportedError("${this.runtimeType}");
+    throw new UnsupportedError("${this.runtimeType}.variableInitialization");
   }
 
   @override
   void set variableInitialization(VariableDeclaration? value) {
-    throw new UnsupportedError("${this.runtimeType}");
+    throw new UnsupportedError("${this.runtimeType}.variableInitialization=");
   }
 
   @override
   VariableContext get context {
-    throw new UnsupportedError("${this.runtimeType}");
+    throw new UnsupportedError("${this.runtimeType}.context");
   }
 
   @override
-  VariableDeclaration get asExpressionVariable => this;
+  void set context(VariableContext value) {
+    throw new UnsupportedError("${this.runtimeType}.context=");
+  }
+
+  @override
+  VariableDeclaration get asVariableDeclaration => this;
 
   @override
   VariableDeclaration get variable => this;
 
   @override
   void set variable(VariableDeclaration value) {
-    throw new UnsupportedError("${this.runtimeType}");
+    throw new UnsupportedError("${this.runtimeType}.variable=");
   }
 
   @override
@@ -2274,78 +2279,117 @@ class VariableInitialization extends Statement implements VariableDeclaration {
   }
 
   @override
-  VariableContext get context => variable.context;
-
-  @override
-  VariableDeclaration get asExpressionVariable => variable;
+  VariableDeclaration get asVariableDeclaration => variable;
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasHasDeclaredInitializer => throw UnimplementedError();
+  VariableContext get context {
+    throw UnsupportedError("${runtimeType}.context");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsConst => throw UnimplementedError();
+  void set context(VariableContext value) {
+    throw UnsupportedError("${runtimeType}.context=");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsCovariantByClass => throw UnimplementedError();
+  bool get hasHasDeclaredInitializer {
+    throw UnsupportedError("${runtimeType}.hasHasDeclaredInitializer");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsCovariantByDeclaration => throw UnimplementedError();
+  bool get hasIsConst {
+    throw new UnsupportedError("${runtimeType}.hasIsConst");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsErroneouslyInitialized => throw UnimplementedError();
+  bool get hasIsCovariantByClass {
+    throw new UnsupportedError("${runtimeType}.hasIsCovariantByClass");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsFinal => throw UnimplementedError();
+  bool get hasIsCovariantByDeclaration {
+    throw new UnsupportedError("${runtimeType}.hasIsCovariantByDeclaration");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsHoisted => throw UnimplementedError();
+  bool get hasIsErroneouslyInitialized {
+    throw new UnsupportedError("${runtimeType}.hasIsErroneouslyInitialized");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsInitializingFormal => throw UnimplementedError();
+  bool get hasIsFinal {
+    throw new UnsupportedError("${runtimeType}.hasIsFinal");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsLate => throw UnimplementedError();
+  bool get hasIsHoisted {
+    throw new UnsupportedError("${runtimeType}.hasIsHoisted");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsLowered => throw UnimplementedError();
+  bool get hasIsInitializingFormal {
+    throw new UnsupportedError("${runtimeType}.hasIsInitializingFormal");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsRequired => throw UnimplementedError();
+  bool get hasIsLate {
+    throw new UnsupportedError("${runtimeType}.hasIsLate");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsSuperInitializingFormal => throw UnimplementedError();
+  bool get hasIsLowered {
+    throw new UnsupportedError("${runtimeType}.hasIsLowered");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsSynthesized => throw UnimplementedError();
+  bool get hasIsRequired {
+    throw new UnsupportedError("${runtimeType}.hasIsRequired");
+  }
 
   @override
   // TODO(62620): Remove the method when the [VariableInitialization] stops
   // implementing [VariableDeclaration].
-  bool get hasIsWildcard => throw UnimplementedError();
+  bool get hasIsSuperInitializingFormal {
+    throw new UnsupportedError("${runtimeType}.hasIsSuperInitializingFormal");
+  }
+
+  @override
+  // TODO(62620): Remove the method when the [VariableInitialization] stops
+  // implementing [VariableDeclaration].
+  bool get hasIsSynthesized {
+    throw new UnsupportedError("${runtimeType}.hasIsSynthesized");
+  }
+
+  @override
+  // TODO(62620): Remove the method when the [VariableInitialization] stops
+  // implementing [VariableDeclaration].
+  bool get hasIsWildcard {
+    throw new UnsupportedError("${runtimeType}.hasIsWildcard");
+  }
 }

pkg/kernel/lib/src/ast/types.dart

@@ -2446,6 +2446,9 @@ class TypeVariable extends VariableBase {
   @override
   String? cosmeticName;
 
+  @override
+  late VariableContext context;
+
   /// Function type parameter this [TypeVariable] is associated with.
   final TypeParameter parameter;
 

pkg/kernel/lib/src/ast/variables.dart

@@ -6,7 +6,7 @@ part of '../../ast.dart';
 
 /// Generalized notion of a variable.
 sealed class VariableBase extends TreeNode implements Annotatable {
-  VariableContext get context => parent as VariableContext;
+  abstract VariableContext context;
 
   /// The cosmetic name of the variable from the source code, if exists.
   String? get cosmeticName;
@@ -30,6 +30,7 @@ abstract interface class IVariable implements TreeNode {
   abstract String? cosmeticName;
   abstract VariableDeclaration? variableInitialization;
   abstract Expression? initializer;
+  abstract VariableContext context;
   abstract bool isFinal;
   abstract bool isConst;
   abstract bool isLate;
@@ -68,7 +69,7 @@ abstract interface class IVariable implements TreeNode {
   bool get hasIsWildcard;
   bool get hasIsSuperInitializingFormal;
   bool get hasIsErroneouslyInitialized;
-  VariableDeclaration get asExpressionVariable;
+  VariableDeclaration get asVariableDeclaration;
 }
 
 /// The root of the sealed hierarchy of non-type variables.
@@ -184,7 +185,7 @@ sealed class VariableDeclaration extends VariableBase
   bool get isAssignable;
 
   @override
-  VariableDeclaration get asExpressionVariable => this;
+  VariableDeclaration get asVariableDeclaration => this;
 
   abstract String? name;
 }
@@ -206,6 +207,9 @@ class LocalVariable extends VariableDeclaration {
   @override
   List<Expression> annotations = const <Expression>[];
 
+  @override
+  late VariableContext context;
+
   LocalVariable({
     this.cosmeticName,
     required DartType? type,
@@ -512,6 +516,9 @@ class CatchVariable extends VariableDeclaration {
   @override
   List<Expression> annotations = const <Expression>[];
 
+  @override
+  late VariableContext context;
+
   CatchVariable({
     required String name,
     required DartType? type,
@@ -1012,6 +1019,9 @@ class PositionalParameter extends FunctionParameter {
   @override
   List<Expression> annotations = const <Expression>[];
 
+  @override
+  late VariableContext context;
+
   PositionalParameter({
     this.cosmeticName,
     required this.type,
@@ -1028,13 +1038,13 @@ class PositionalParameter extends FunctionParameter {
   });
 
   @override
-  // TODO(62620): Conforming to [VariableInitialization] interface. Remove this.
+  // TODO(62620): Conforming to [VariableDeclaration] interface. Remove this.
   List<VariableContext>? get capturedContexts {
     throw new UnsupportedError("${this.runtimeType}.capturedContexts");
   }
 
   @override
-  // TODO(62620): Conforming to [VariableInitialization] interface. Remove this.
+  // TODO(62620): Conforming to [VariableDeclaration] interface. Remove this.
   void set capturedContexts(List<VariableContext>? value) {
     throw new UnsupportedError("${this.runtimeType}.capturedContexts=");
   }
@@ -1156,6 +1166,9 @@ class NamedParameter extends FunctionParameter {
   @override
   List<Expression> annotations = const <Expression>[];
 
+  @override
+  late VariableContext context;
+
   NamedParameter({
     required this.parameterName,
     required this.type,
@@ -1172,13 +1185,13 @@ class NamedParameter extends FunctionParameter {
   });
 
   @override
-  // TODO(62620): Conforming to [VariableInitialization] interface. Remove this.
+  // TODO(62620): Conforming to [VariableDeclaration] interface. Remove this.
   List<VariableContext>? get capturedContexts {
     throw new UnsupportedError("${this.runtimeType}.capturedContexts");
   }
 
   @override
-  // TODO(62620): Conforming to [VariableInitialization] interface. Remove this.
+  // TODO(62620): Conforming to [VariableDeclaration] interface. Remove this.
   void set capturedContexts(List<VariableContext>? value) {
     throw new UnsupportedError("${this.runtimeType}.capturedContexts=");
   }
@@ -1303,6 +1316,9 @@ class ThisVariable extends VariableDeclaration {
   @override
   List<Expression> annotations = const <Expression>[];
 
+  @override
+  late VariableContext context;
+
   ThisVariable({required this.type}) : super.empty();
 
   // TODO(cstefantsova): Consider a throwing implementation instead.
@@ -1578,6 +1594,9 @@ class SyntheticVariable extends VariableDeclaration {
   @override
   List<Expression> annotations = const <Expression>[];
 
+  @override
+  late VariableContext context;
+
   SyntheticVariable({this.cosmeticName, required this.type}) : super.empty();
 
   // TODO(cstefantsova): Consider a throwing implementation instead.
@@ -1854,7 +1873,7 @@ class VariableContext extends TreeNode {
   VariableContext({required this.captureKind, required this.variables});
 
   void addVariable(VariableBase variable) {
-    variable.parent = this;
+    variable.context = this;
     variables.add(variable);
   }
 

pkg/kernel/lib/src/equivalence.dart

@@ -6060,6 +6060,9 @@ class EquivalenceStrategy {
     if (!checkLocalVariable_annotations(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
+    if (!checkLocalVariable_context(visitor, node, other)) {
+      result = visitor.resultOnInequivalence;
+    }
     if (!checkLocalVariable_binaryOffsetNoTag(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
@@ -6095,6 +6098,9 @@ class EquivalenceStrategy {
     if (!checkCatchVariable_annotations(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
+    if (!checkCatchVariable_context(visitor, node, other)) {
+      result = visitor.resultOnInequivalence;
+    }
     if (!checkCatchVariable_binaryOffsetNoTag(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
@@ -6130,6 +6136,9 @@ class EquivalenceStrategy {
     if (!checkPositionalParameter_annotations(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
+    if (!checkPositionalParameter_context(visitor, node, other)) {
+      result = visitor.resultOnInequivalence;
+    }
     if (!checkPositionalParameter_binaryOffsetNoTag(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
@@ -6168,6 +6177,9 @@ class EquivalenceStrategy {
     if (!checkNamedParameter_annotations(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
+    if (!checkNamedParameter_context(visitor, node, other)) {
+      result = visitor.resultOnInequivalence;
+    }
     if (!checkNamedParameter_binaryOffsetNoTag(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
@@ -6203,6 +6215,9 @@ class EquivalenceStrategy {
     if (!checkThisVariable_annotations(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
+    if (!checkThisVariable_context(visitor, node, other)) {
+      result = visitor.resultOnInequivalence;
+    }
     if (!checkThisVariable_binaryOffsetNoTag(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
@@ -6241,6 +6256,9 @@ class EquivalenceStrategy {
     if (!checkSyntheticVariable_annotations(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
+    if (!checkSyntheticVariable_context(visitor, node, other)) {
+      result = visitor.resultOnInequivalence;
+    }
     if (!checkSyntheticVariable_binaryOffsetNoTag(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
@@ -6270,6 +6288,9 @@ class EquivalenceStrategy {
     if (!checkTypeVariable_cosmeticName(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
+    if (!checkTypeVariable_context(visitor, node, other)) {
+      result = visitor.resultOnInequivalence;
+    }
     if (!checkTypeVariable_parameter(visitor, node, other)) {
       result = visitor.resultOnInequivalence;
     }
@@ -13513,6 +13534,14 @@ class EquivalenceStrategy {
     );
   }
 
+  bool checkLocalVariable_context(
+    EquivalenceVisitor visitor,
+    LocalVariable node,
+    LocalVariable other,
+  ) {
+    return visitor.checkNodes(node.context, other.context, 'context');
+  }
+
   bool checkLocalVariable_binaryOffsetNoTag(
     EquivalenceVisitor visitor,
     LocalVariable node,
@@ -13618,6 +13647,14 @@ class EquivalenceStrategy {
     );
   }
 
+  bool checkCatchVariable_context(
+    EquivalenceVisitor visitor,
+    CatchVariable node,
+    CatchVariable other,
+  ) {
+    return visitor.checkNodes(node.context, other.context, 'context');
+  }
+
   bool checkCatchVariable_binaryOffsetNoTag(
     EquivalenceVisitor visitor,
     CatchVariable node,
@@ -13691,6 +13728,14 @@ class EquivalenceStrategy {
     );
   }
 
+  bool checkPositionalParameter_context(
+    EquivalenceVisitor visitor,
+    PositionalParameter node,
+    PositionalParameter other,
+  ) {
+    return visitor.checkNodes(node.context, other.context, 'context');
+  }
+
   bool checkPositionalParameter_binaryOffsetNoTag(
     EquivalenceVisitor visitor,
     PositionalParameter node,
@@ -13800,6 +13845,14 @@ class EquivalenceStrategy {
     );
   }
 
+  bool checkNamedParameter_context(
+    EquivalenceVisitor visitor,
+    NamedParameter node,
+    NamedParameter other,
+  ) {
+    return visitor.checkNodes(node.context, other.context, 'context');
+  }
+
   bool checkNamedParameter_binaryOffsetNoTag(
     EquivalenceVisitor visitor,
     NamedParameter node,
@@ -13869,6 +13922,14 @@ class EquivalenceStrategy {
     );
   }
 
+  bool checkThisVariable_context(
+    EquivalenceVisitor visitor,
+    ThisVariable node,
+    ThisVariable other,
+  ) {
+    return visitor.checkNodes(node.context, other.context, 'context');
+  }
+
   bool checkThisVariable_binaryOffsetNoTag(
     EquivalenceVisitor visitor,
     ThisVariable node,
@@ -13954,6 +14015,14 @@ class EquivalenceStrategy {
     );
   }
 
+  bool checkSyntheticVariable_context(
+    EquivalenceVisitor visitor,
+    SyntheticVariable node,
+    SyntheticVariable other,
+  ) {
+    return visitor.checkNodes(node.context, other.context, 'context');
+  }
+
   bool checkSyntheticVariable_binaryOffsetNoTag(
     EquivalenceVisitor visitor,
     SyntheticVariable node,
@@ -14006,6 +14075,14 @@ class EquivalenceStrategy {
     );
   }
 
+  bool checkTypeVariable_context(
+    EquivalenceVisitor visitor,
+    TypeVariable node,
+    TypeVariable other,
+  ) {
+    return visitor.checkNodes(node.context, other.context, 'context');
+  }
+
   bool checkTypeVariable_parameter(
     EquivalenceVisitor visitor,
     TypeVariable node,

pkg/kernel/lib/verifier.dart

@@ -1180,11 +1180,6 @@ class VerifyingVisitor extends RecursiveResultVisitor<void> {
     exitTreeNode(node);
   }
 
-  @override
-  void visitLocalVariable(LocalVariable node) {
-    declareVariable(node);
-  }
-
   @override
   void visitVariableGet(VariableGet node) {
     // TODO(cstefantsova): Support new variable model.