Merge pull request #7352 from genlu/IOperationTree

Make all internal nodes of IOperation tree subtypes of IOperation

src/Compilers/CSharp/Portable/BoundTree/Statement.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System;
 using System.Collections.Immutable;
+using System.Runtime.CompilerServices;
 using Microsoft.CodeAnalysis.Semantics;
 
 namespace Microsoft.CodeAnalysis.CSharp
@@ -124,7 +126,7 @@ ImmutableArray<IStatement> ToStatements(BoundStatement statement)
             {
                 return ImmutableArray<IStatement>.Empty;
             }
-            
+
             return ImmutableArray.Create<IStatement>(statement);
         }
     }
@@ -142,7 +144,7 @@ partial class BoundForEachStatement : IForEachLoopStatement
         protected override OperationKind StatementKind => OperationKind.LoopStatement;
     }
 
-    partial class BoundSwitchStatement: ISwitchStatement
+    partial class BoundSwitchStatement : ISwitchStatement
     {
         IExpression ISwitchStatement.Value => this.BoundExpression;
 
@@ -156,6 +158,8 @@ partial class BoundSwitchSection : ICase
         ImmutableArray<ICaseClause> ICase.Clauses => this.BoundSwitchLabels.As<ICaseClause>();
 
         ImmutableArray<IStatement> ICase.Body => this.Statements.As<IStatement>();
+
+        protected override OperationKind StatementKind => OperationKind.SwitchSection;
     }
 
     partial class BoundSwitchLabel : ISingleValueCaseClause
@@ -200,6 +204,12 @@ BinaryOperationKind ISingleValueCaseClause.Equality
         }
 
         CaseKind ICaseClause.CaseKind => this.ExpressionOpt != null ? CaseKind.SingleValue : CaseKind.Default;
+
+        OperationKind IOperation.Kind => OperationKind.SingleValueCaseClause;
+
+        bool IOperation.IsInvalid => this.HasErrors;
+
+        SyntaxNode IOperation.Syntax => this.Syntax;
     }
 
     partial class BoundTryStatement : ITryStatement
@@ -239,7 +249,7 @@ partial class BoundFixedStatement : IFixedStatement
         protected override OperationKind StatementKind => OperationKind.FixedStatement;
     }
 
-    partial class BoundUsingStatement: IUsingWithDeclarationStatement, IUsingWithExpressionStatement
+    partial class BoundUsingStatement : IUsingWithDeclarationStatement, IUsingWithExpressionStatement
     {
         IVariableDeclarationStatement IUsingWithDeclarationStatement.Variables => this.DeclarationsOpt;
 
@@ -310,20 +320,38 @@ partial class BoundStateMachineScope
         protected override OperationKind StatementKind => OperationKind.None;
     }
 
-    partial class BoundLocalDeclaration : IVariableDeclarationStatement, IVariable
+    partial class BoundLocalDeclaration : IVariableDeclarationStatement
     {
-        ImmutableArray<IVariable> IVariableDeclarationStatement.Variables => ImmutableArray.Create<IVariable>(this);
-
-        ILocalSymbol IVariable.Variable => this.LocalSymbol;
+        private static readonly ConditionalWeakTable<BoundLocalDeclaration, object> s_variablesMappings =
+            new ConditionalWeakTable<BoundLocalDeclaration, object>();
 
-        IExpression IVariable.InitialValue => this.InitializerOpt;
+        ImmutableArray<IVariable> IVariableDeclarationStatement.Variables
+        {
+            get
+            {
+                return (ImmutableArray<IVariable>) s_variablesMappings.GetValue(this, 
+                    declaration => ImmutableArray.Create<IVariable>(new VariableDeclaration(declaration.LocalSymbol, declaration.InitializerOpt, declaration.Syntax)));
+            }
+        }
 
         protected override OperationKind StatementKind => OperationKind.VariableDeclarationStatement;
     }
 
     partial class BoundMultipleLocalDeclarations : IVariableDeclarationStatement
     {
-        ImmutableArray<IVariable> IVariableDeclarationStatement.Variables => this.LocalDeclarations.As<IVariable>();
+        private static readonly ConditionalWeakTable<BoundMultipleLocalDeclarations, object> s_variablesMappings =
+            new ConditionalWeakTable<BoundMultipleLocalDeclarations, object>();
+
+        ImmutableArray<IVariable> IVariableDeclarationStatement.Variables
+        {
+            get
+            {
+                return (ImmutableArray<IVariable>)s_variablesMappings.GetValue(this,
+                    multipleDeclarations =>
+                        multipleDeclarations.LocalDeclarations.SelectAsArray(declaration => 
+                            (IVariable)new VariableDeclaration(declaration.LocalSymbol, declaration.InitializerOpt, declaration.Syntax)));
+            }
+        }
 
         protected override OperationKind StatementKind => OperationKind.VariableDeclarationStatement;
     }

src/Compilers/Core/Portable/Compilation/Expression.cs

@@ -255,14 +255,14 @@ public sealed class Binary : IBinaryOperatorExpression
     {
         public Binary(BinaryOperationKind binaryKind, IExpression left, IExpression right, ITypeSymbol resultType, SyntaxNode syntax)
         {
-            this.BinaryKind = binaryKind;
+            this.BinaryOperationKind = binaryKind;
             this.Left = left;
             this.Right = right;
             this.ResultType = resultType;
             this.Syntax = syntax;
         }
 
-        public BinaryOperationKind BinaryKind { get; }
+        public BinaryOperationKind BinaryOperationKind { get; }
 
         public IExpression Left { get; }
 
@@ -291,7 +291,7 @@ public ArrayCreation(IArrayTypeSymbol arrayType, ImmutableArray<IExpression> ele
         {
             _arrayType = arrayType;
             this.DimensionSizes = ImmutableArray.Create<IExpression>(new IntegerLiteral(elementValues.Count(), null, syntax));
-            this.ElementValues = new DimensionInitializer(elementValues);
+            this.Initializer = new ArrayInitializer(elementValues, syntax, arrayType);
             this.Syntax = syntax;
         }
 
@@ -301,68 +301,38 @@ public ArrayCreation(IArrayTypeSymbol arrayType, ImmutableArray<IExpression> ele
 
         public ITypeSymbol ElementType => _arrayType.ElementType;
 
-        public IArrayInitializer ElementValues { get; }
+        public IArrayInitializer Initializer { get; }
 
         public SyntaxNode Syntax { get; }
 
         public OperationKind Kind => OperationKind.ArrayCreationExpression;
 
-        public bool IsInvalid => IsInvalidInitializer(ElementValues);
+        public bool IsInvalid => IsInvalidInitializer(Initializer);
        
-        static bool IsInvalidInitializer(IArrayInitializer initializer)
-        {
-            switch (initializer.ArrayClass)
-            {
-                case ArrayInitializerKind.Dimension:
-                    foreach (IArrayInitializer element in ((IDimensionArrayInitializer)initializer).ElementValues)
-                    {
-                        if (IsInvalidInitializer(element))
-                        {
-                            return true;
-                        }
-                    }
-
-                    break;
-
-                case ArrayInitializerKind.Expression:
-                    return ((IExpressionArrayInitializer)initializer).ElementValue.IsInvalid;
-            }
-
-            return false;
-        }
+        static bool IsInvalidInitializer(IArrayInitializer initializer) => initializer.IsInvalid;
 
         public Optional<object> ConstantValue => default(Optional<object>);
 
-        private class DimensionInitializer : IDimensionArrayInitializer
+        private class ArrayInitializer : IArrayInitializer
         {
-            private readonly ImmutableArray<IArrayInitializer> _elementValues;
-
-            public DimensionInitializer(ImmutableArray<IExpression> elementValues)
+            public ArrayInitializer(ImmutableArray<IExpression> elementValues, SyntaxNode syntax, ITypeSymbol arrayType)
             {
-                ArrayBuilder<IArrayInitializer> builder = ArrayBuilder<IArrayInitializer>.GetInstance();
-                foreach (IExpression element in elementValues)
-                {
-                    builder.Add(new ExpressionInitializer(element));
-                }
-
-                _elementValues = builder.ToImmutableAndFree();
+                ElementValues = elementValues;
+                Syntax = syntax;
+                ResultType = arrayType;
             }
 
-            public ArrayInitializerKind ArrayClass => ArrayInitializerKind.Dimension;
+            public ImmutableArray<IExpression> ElementValues { get; }
 
-            public ImmutableArray<IArrayInitializer> ElementValues => _elementValues;
-        }
+            public bool IsInvalid => ElementValues.Any(v => v.IsInvalid);
 
-        private class ExpressionInitializer : IExpressionArrayInitializer
-        {
-            public ExpressionInitializer(IExpression expression)
-            {
-                ElementValue = expression;
-            }
+            public OperationKind Kind => OperationKind.ArrayInitializer;
 
-            public ArrayInitializerKind ArrayClass => ArrayInitializerKind.Expression;
+            public ITypeSymbol ResultType { get; }
 
-            public IExpression ElementValue { get; }
+            public SyntaxNode Syntax { get; }
+
+            public Optional<object> ConstantValue => default(Optional<object>);
         }
     }
     

src/Compilers/Core/Portable/Compilation/IExpression.cs

@@ -59,12 +59,12 @@ public interface IInvocationExpression : IExpression
     /// <summary>
     /// Represents an argument in a method invocation.
     /// </summary>
-    public interface IArgument
+    public interface IArgument : IOperation
     {
         /// <summary>
         /// Kind of argument.
         /// </summary>
-        ArgumentKind Kind { get; }
+        ArgumentKind ArgumentKind { get; }
         /// <summary>
         /// Parameter the argument matches.
         /// </summary>
@@ -329,7 +329,7 @@ public interface IUnaryOperatorExpression : IHasOperatorExpression
         /// <summary>
         /// Kind of unary operation.
         /// </summary>
-        UnaryOperationKind UnaryKind { get; }
+        UnaryOperationKind UnaryOperationKind { get; }
         /// <summary>
         /// Single operand.
         /// </summary>
@@ -418,7 +418,7 @@ public interface IBinaryOperatorExpression : IHasOperatorExpression
         /// <summary>
         /// Kind of binary operation.
         /// </summary>
-        BinaryOperationKind BinaryKind { get; }
+        BinaryOperationKind BinaryOperationKind { get; }
         /// <summary>
         /// Left operand.
         /// </summary>
@@ -620,7 +620,7 @@ public interface IConversionExpression : IHasOperatorExpression
         /// <summary>
         /// Kind of conversion.
         /// </summary>
-        ConversionKind Conversion { get; }
+        ConversionKind ConversionKind { get; }
         /// <summary>
         /// True if and only if the conversion is indicated explicity by a cast operation in the source code.
         /// </summary>
@@ -712,7 +712,7 @@ public interface ITypeOperationExpression : IExpression
         /// <summary>
         /// Kind of type operation.
         /// </summary>
-        TypeOperationKind TypeOperationClass { get; }
+        TypeOperationKind TypeOperationKind { get; }
         /// <summary>
         /// Type operand.
         /// </summary>
@@ -798,9 +798,12 @@ public interface IObjectCreationExpression : IExpression
         ImmutableArray<IMemberInitializer> MemberInitializers { get; }
     }
 
-    public interface IMemberInitializer
+    /// <summary>
+    /// Represents an object member initializer.
+    /// </summary>
+    public interface IMemberInitializer : IOperation
     {
-        MemberInitializerKind MemberClass { get; }
+        MemberInitializerKind MemberInitializerKind { get; }
         IExpression Value { get; }
     }
 
@@ -851,49 +854,18 @@ public interface IArrayCreationExpression : IExpression
         /// <summary>
         /// Values of elements of the created array instance.
         /// </summary>
-        IArrayInitializer ElementValues { get; }
+        IArrayInitializer Initializer { get; }
     }
 
     /// <summary>
     /// Represents the initialization of an array instance.
     /// </summary>
-    public interface IArrayInitializer
+    public interface IArrayInitializer : IExpression
     {
         /// <summary>
-        /// Kind of array initialization.
-        /// </summary>
-        ArrayInitializerKind ArrayClass { get; }
-    }
-
-    /// <summary>
-    /// Kinds of array initializers.
-    /// </summary>
-    public enum ArrayInitializerKind
-    {
-        /// <summary>
-        /// Initializer specifies a single element value.
-        /// </summary>
-        Expression,
-        /// <summary>
-        /// Initializer specifies multiple elements of a dimension of the array. 
+        /// Values to initialize array elements.
         /// </summary>
-        Dimension
-    }
-
-    /// <summary>
-    /// Represents an initialization of a single element of an array instance.
-    /// </summary>
-    public interface IExpressionArrayInitializer : IArrayInitializer
-    {
-        IExpression ElementValue { get; }
-    }
-
-    /// <summary>
-    /// Represents an initialization of a single dimension of an array instance.
-    /// </summary>
-    public interface IDimensionArrayInitializer : IArrayInitializer
-    {
-        ImmutableArray<IArrayInitializer> ElementValues { get; }
+        ImmutableArray<IExpression> ElementValues { get; }
     }
 
     /// <summary>

src/Compilers/Core/Portable/Compilation/IOperation.cs

@@ -106,6 +106,16 @@ public enum OperationKind
         // Newly added
 
         ConditionalAccessExpression,
-        IncrementExpression
+        IncrementExpression,
+
+        Argument,
+        FieldInitializer,
+        PropertyInitializer,
+        ArrayInitializer,
+        VariableDeclaration,
+        SwitchSection,
+        SingleValueCaseClause,
+        RelationalCaseClause,
+        RangeCaseClause
     }
 }

src/Compilers/Core/Portable/Compilation/IStatement.cs

@@ -40,7 +40,7 @@ public interface IVariableDeclarationStatement : IStatement
     /// <summary>
     /// Represents a local variable declaration.
     /// </summary>
-    public interface IVariable
+    public interface IVariable : IOperation
     {
         /// <summary>
         /// Variable declared by the declaration.
@@ -70,7 +70,7 @@ public interface ISwitchStatement : IStatement
     /// <summary>
     /// Represents a C# case or VB Case statement.
     /// </summary>
-    public interface ICase
+    public interface ICase : IStatement
     {
         /// <summary>
         /// Clauses of the case. For C# there is one clause per case, but for VB there can be multiple.
@@ -85,7 +85,7 @@ public interface ICase
     /// <summary>
     /// Represents a clause of a C# case or a VB Case.
     /// </summary>
-    public interface ICaseClause
+    public interface ICaseClause : IOperation
     {
         /// <summary>
         /// Kind of the clause.

src/Compilers/Core/Portable/Compilation/Statement.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+
 namespace Microsoft.CodeAnalysis.Semantics
 {
-  
+    internal sealed class VariableDeclaration : IVariable
+    {
+        public VariableDeclaration(ILocalSymbol variable, IExpression initialValue, SyntaxNode syntax)
+        {
+            Variable = variable;
+            InitialValue = initialValue;
+            Syntax = syntax;
+        }
+
+        public ILocalSymbol Variable { get; }
+
+        public IExpression InitialValue { get; }
+
+        public bool IsInvalid => Variable == null || (InitialValue != null && InitialValue.IsInvalid);
+
+        public OperationKind Kind => OperationKind.VariableDeclaration;
+
+        public SyntaxNode Syntax { get; }
+    }
 }
\ No newline at end of file

src/Compilers/VisualBasic/Portable/BoundTree/Statement.vb

@@ -90,12 +90,15 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             End Get
         End Property
 
+        Private Shared ReadOnly CaseElseMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundCaseStatement, Object)
+
         Private ReadOnly Property IClauses As ImmutableArray(Of ICaseClause) Implements ICase.Clauses
             Get
                 ' `CaseElseClauseSyntax` is bound to `BoundCaseStatement` with an empty list of case clauses, 
                 ' so we explicitly create an IOperation node for Case-Else clause to differentiate it from Case clause.
                 If Me.CaseStatement.CaseClauses.IsEmpty AndAlso Me.CaseStatement.Syntax.Kind() = SyntaxKind.CaseElseStatement Then
-                    Return ImmutableArray.Create(CaseElseClause)
+                    Dim caseElse = CaseElseMappings.GetValue(Me.CaseStatement, Function(caseStatement) ImmutableArray.Create(Of ICaseClause)(New CaseElse(caseStatement)))
+                    Return DirectCast(caseElse, ImmutableArray(Of ICaseClause))
                 End If
 
                 Return Me.CaseStatement.CaseClauses.As(Of ICaseClause)()
@@ -103,13 +106,48 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
         End Property
 
         Protected Overrides Function StatementKind() As OperationKind
-            Return OperationKind.None
+            Return OperationKind.SwitchSection
         End Function
 
-        Private Shared CaseElseClause As ICaseClause = New CaseElse
-
         Private Class CaseElse
-            Implements ICaseClause
+            Implements ISingleValueCaseClause
+
+            Private _boundCaseStatement As BoundCaseStatement
+
+            Public Sub New(boundCaseStatement As BoundCaseStatement)
+                _boundCaseStatement = boundCaseStatement
+            End Sub
+
+            Public ReadOnly Property Equality As BinaryOperationKind Implements ISingleValueCaseClause.Equality
+                Get
+                    Return BinaryOperationKind.None
+                End Get
+            End Property
+
+            Public ReadOnly Property Value As IExpression Implements ISingleValueCaseClause.Value
+                Get
+                    Return Nothing
+                End Get
+            End Property
+
+            Public ReadOnly Property IsInvalid As Boolean Implements IOperation.IsInvalid
+                Get
+                    Return _boundCaseStatement.HasErrors
+                End Get
+            End Property
+
+            Public ReadOnly Property Kind As OperationKind Implements IOperation.Kind
+                Get
+                    Return OperationKind.SingleValueCaseClause
+                End Get
+            End Property
+
+            Public ReadOnly Property Syntax As SyntaxNode Implements IOperation.Syntax
+                Get
+                    Return _boundCaseStatement.Syntax
+                End Get
+            End Property
+
             Private ReadOnly Property ICaseClass As CaseKind Implements ICaseClause.CaseKind
                 Get
                     Return CaseKind.Default
@@ -122,7 +160,22 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
     Partial Class BoundCaseClause
         Implements ICaseClause
 
-        Protected MustOverride ReadOnly Property ICaseClass As CaseKind Implements ICaseClause.CaseKind
+
+        Private ReadOnly Property IIsInvalid As Boolean Implements IOperation.IsInvalid
+            Get
+                Return Me.HasErrors
+            End Get
+        End Property
+
+        Private ReadOnly Property ISyntax As SyntaxNode Implements IOperation.Syntax
+            Get
+                Return Me.Syntax
+            End Get
+        End Property
+
+        Protected MustOverride ReadOnly Property IKind As OperationKind Implements IOperation.Kind
+
+        Protected MustOverride ReadOnly Property ICaseKind As CaseKind Implements ICaseClause.CaseKind
     End Class
 
     Partial Class BoundSimpleCaseClause
@@ -170,7 +223,13 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             End Get
         End Property
 
-        Protected Overrides ReadOnly Property ICaseClass As CaseKind
+        Protected Overrides ReadOnly Property IKind As OperationKind
+            Get
+                Return OperationKind.SingleValueCaseClause
+            End Get
+        End Property
+
+        Protected Overrides ReadOnly Property ICaseKind As CaseKind
             Get
                 Return CaseKind.SingleValue
             End Get
@@ -214,7 +273,13 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             End Get
         End Property
 
-        Protected Overrides ReadOnly Property ICaseClass As CaseKind
+        Protected Overrides ReadOnly Property IKind As OperationKind
+            Get
+                Return OperationKind.RangeCaseClause
+            End Get
+        End Property
+
+        Protected Overrides ReadOnly Property ICaseKind As CaseKind
             Get
                 Return CaseKind.Range
             End Get
@@ -248,7 +313,13 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             End Get
         End Property
 
-        Protected Overrides ReadOnly Property ICaseClass As CaseKind
+        Protected Overrides ReadOnly Property IKind As OperationKind
+            Get
+                Return OperationKind.RelationalCaseClause
+            End Get
+        End Property
+
+        Protected Overrides ReadOnly Property ICaseKind As CaseKind
             Get
                 Return CaseKind.Relational
             End Get
@@ -305,11 +376,11 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
     Partial Class BoundForToStatement
         Implements IForLoopStatement
 
-        Private Shared LoopBottomMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundForToStatement, Object)
+        Private Shared ReadOnly s_loopBottomMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundForToStatement, Object)
 
         Private ReadOnly Property IAtLoopBottom As ImmutableArray(Of IStatement) Implements IForLoopStatement.AtLoopBottom
             Get
-                Dim result = LoopBottomMappings.GetValue(
+                Dim result = s_loopBottomMappings.GetValue(
                     Me,
                     Function(BoundFor)
                         Dim statements As ArrayBuilder(Of IStatement) = ArrayBuilder(Of IStatement).GetInstance()
@@ -341,11 +412,11 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             End Get
         End Property
 
-        Private Shared LoopTopMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundForToStatement, Object)
+        Private Shared ReadOnly s_loopTopMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundForToStatement, Object)
 
         Private ReadOnly Property IBefore As ImmutableArray(Of IStatement) Implements IForLoopStatement.Before
             Get
-                Dim result = LoopTopMappings.GetValue(
+                Dim result = s_loopTopMappings.GetValue(
                     Me,
                     Function(BoundFor)
                         Dim statements As ArrayBuilder(Of IStatement) = ArrayBuilder(Of IStatement).GetInstance()
@@ -379,11 +450,11 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             End Get
         End Property
 
-        Private Shared LoopConditionMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundForToStatement, IExpression)
+        Private Shared ReadOnly s_loopConditionMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundForToStatement, IExpression)
 
         Private ReadOnly Property ICondition As IExpression Implements IForWhileUntilLoopStatement.Condition
             Get
-                Return LoopConditionMappings.GetValue(
+                Return s_loopConditionMappings.GetValue(
                     Me,
                     Function(BoundFor)
                         Dim limitValue As IExpression = If(BoundFor.LimitValue.IsConstant, DirectCast(BoundFor.LimitValue, IExpression), New Temporary(SyntheticLocalKind.ForLoopLimitValue, BoundFor, BoundFor.LimitValue))
@@ -700,75 +771,30 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
         End Function
     End Class
 
-    Partial Class BoundLocalDeclarationBase
-        Implements IVariable
-
-        Protected MustOverride ReadOnly Property IInitialValue As IExpression Implements IVariable.InitialValue
-
-        Protected MustOverride ReadOnly Property IVariable As ILocalSymbol Implements IVariable.Variable
-    End Class
-
-    Partial Class BoundLocalDeclaration
-        Implements IVariableDeclarationStatement
-
-        Private ReadOnly Property IVariables As ImmutableArray(Of IVariable) Implements IVariableDeclarationStatement.Variables
-            Get
-                Return ImmutableArray.Create(Of IVariable)(Me)
-            End Get
-        End Property
-
-        Protected Overrides ReadOnly Property IInitialValue As IExpression
-            Get
-                Return Me.InitializerOpt
-            End Get
-        End Property
-
-        Protected Overrides ReadOnly Property IVariable As ILocalSymbol
-            Get
-                Return Me.LocalSymbol
-            End Get
-        End Property
-
-        Protected Overrides Function StatementKind() As OperationKind
-            Return OperationKind.VariableDeclarationStatement
-        End Function
-    End Class
-
-    Partial Class BoundAsNewLocalDeclarations
-        Implements IVariableDeclarationStatement
-
-        Private ReadOnly Property IVariables As ImmutableArray(Of IVariable) Implements IVariableDeclarationStatement.Variables
-            Get
-                Return Me.LocalDeclarations.As(Of IVariable)()
-            End Get
-        End Property
-
-        Protected Overrides ReadOnly Property IInitialValue As IExpression
-            Get
-                Return Me.Initializer
-            End Get
-        End Property
-
-        Protected Overrides ReadOnly Property IVariable As ILocalSymbol
-            Get
-                ' ZZZ Get clear about what's happening in the VB bound trees. BoundAsNewLocalDeclarations has multiple symbols and
-                ' inherits from BoundLocalDeclarationBase, which occurs multiply in BoundDimStatement.
-                Dim local As BoundLocalDeclaration = Me.LocalDeclarations.FirstOrDefault()
-                Return If(local IsNot Nothing, local.LocalSymbol, Nothing)
-            End Get
-        End Property
-
-        Protected Overrides Function StatementKind() As OperationKind
-            Return OperationKind.VariableDeclarationStatement
-        End Function
-    End Class
-
     Partial Class BoundDimStatement
         Implements IVariableDeclarationStatement
 
+        Private Shared ReadOnly s_variablesMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundDimStatement, Object)
+
         Private ReadOnly Property IVariables As ImmutableArray(Of IVariable) Implements IVariableDeclarationStatement.Variables
             Get
-                Return Me.LocalDeclarations.As(Of IVariable)()
+                Dim variables = s_variablesMappings.GetValue(Me, Function(dimStatement)
+                                                                     Dim builder = ArrayBuilder(Of IVariable).GetInstance()
+                                                                     For Each base In dimStatement.LocalDeclarations
+                                                                         If base.Kind = BoundKind.LocalDeclaration Then
+                                                                             Dim declaration = DirectCast(base, BoundLocalDeclaration)
+                                                                             builder.Add(New VariableDeclaration(declaration.LocalSymbol, declaration.InitializerOpt, declaration.Syntax))
+                                                                         ElseIf base.Kind = BoundKind.AsNewLocalDeclarations Then
+                                                                             Dim asNewDeclarations = DirectCast(base, BoundAsNewLocalDeclarations)
+                                                                             For Each asNewDeclaration In asNewDeclarations.LocalDeclarations
+                                                                                 builder.Add(New VariableDeclaration(asNewDeclaration.LocalSymbol, asNewDeclarations.Initializer, asNewDeclaration.Syntax))
+                                                                             Next
+                                                                         End If
+                                                                     Next
+                                                                     Return builder.ToImmutableAndFree()
+                                                                 End Function
+                                                               )
+                Return DirectCast(variables, ImmutableArray(Of IVariable))
             End Get
         End Property
 
@@ -931,11 +957,11 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             End Get
         End Property
 
-        Private Shared VariablesMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundUsingStatement, Variables)
+        Private Shared ReadOnly s_variablesMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundUsingStatement, Variables)
 
         Private ReadOnly Property IVariables As IVariableDeclarationStatement Implements IUsingWithDeclarationStatement.Variables
             Get
-                Return VariablesMappings.GetValue(
+                Return s_variablesMappings.GetValue(
                     Me,
                     Function(BoundUsing)
                         Return New Variables(BoundUsing.ResourceList.As(Of IVariable))
@@ -1003,69 +1029,111 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
     End Class
 
     Partial Class BoundAddRemoveHandlerStatement
-        Implements IEventAssignmentExpression
+        Implements IExpressionStatement
 
-        Protected MustOverride ReadOnly Property IAdds As Boolean Implements IEventAssignmentExpression.Adds
+        Protected Shared ReadOnly s_expressionsMappings As New System.Runtime.CompilerServices.ConditionalWeakTable(Of BoundAddRemoveHandlerStatement, IEventAssignmentExpression)
 
-        Private ReadOnly Property IConstantValue As [Optional](Of Object) Implements IExpression.ConstantValue
-            Get
-                Return New [Optional](Of Object)()
-            End Get
-        End Property
+        Protected Overrides Function StatementKind() As OperationKind
+            Return OperationKind.ExpressionStatement
+        End Function
 
-        Private ReadOnly Property IEvent As IEventSymbol Implements IEventAssignmentExpression.Event
-            Get
-                Dim eventAccess As BoundEventAccess = TryCast(Me.EventAccess, BoundEventAccess)
-                If eventAccess IsNot Nothing Then
-                    Return eventAccess.EventSymbol
-                End If
+        Protected MustOverride ReadOnly Property IExpression As IExpression Implements IExpressionStatement.Expression
 
-                Return Nothing
-            End Get
-        End Property
+        Protected Class EventAssignmentExpression
+            Implements IEventAssignmentExpression
 
-        Private ReadOnly Property IEventInstance As IExpression Implements IEventAssignmentExpression.EventInstance
-            Get
-                Dim eventAccess As BoundEventAccess = TryCast(Me.EventAccess, BoundEventAccess)
-                If eventAccess IsNot Nothing Then
-                    Return eventAccess.ReceiverOpt
-                End If
+            Private ReadOnly _statement As BoundAddRemoveHandlerStatement
+            Private ReadOnly _adds As Boolean
 
-                Return Nothing
-            End Get
-        End Property
+            Public Sub New(statement As BoundAddRemoveHandlerStatement, adds As Boolean)
+                _statement = statement
+                _adds = adds
+            End Sub
 
-        Private ReadOnly Property IResultType As ITypeSymbol Implements IExpression.ResultType
-            Get
-                Return Nothing
-            End Get
-        End Property
+            Public ReadOnly Property Adds As Boolean Implements IEventAssignmentExpression.Adds
+                Get
+                    Return _adds
+                End Get
+            End Property
 
-        Private ReadOnly Property IHandlerValue As IExpression Implements IEventAssignmentExpression.HandlerValue
-            Get
-                Return Me.Handler
-            End Get
-        End Property
+            Public ReadOnly Property ConstantValue As [Optional](Of Object) Implements IExpression.ConstantValue
+                Get
+                    Return New [Optional](Of Object)()
+                End Get
+            End Property
 
-        Protected Overrides Function StatementKind() As OperationKind
-            Return OperationKind.EventAssignmentExpression
-        End Function
+            Public ReadOnly Property [Event] As IEventSymbol Implements IEventAssignmentExpression.Event
+                Get
+                    Dim eventAccess As BoundEventAccess = TryCast(_statement.EventAccess, BoundEventAccess)
+                    If eventAccess IsNot Nothing Then
+                        Return eventAccess.EventSymbol
+                    End If
+
+                    Return Nothing
+                End Get
+            End Property
+
+            Public ReadOnly Property EventInstance As IExpression Implements IEventAssignmentExpression.EventInstance
+                Get
+                    Dim eventAccess As BoundEventAccess = TryCast(_statement.EventAccess, BoundEventAccess)
+                    If eventAccess IsNot Nothing Then
+                        Return eventAccess.ReceiverOpt
+                    End If
+
+                    Return Nothing
+                End Get
+            End Property
+
+            Public ReadOnly Property HandlerValue As IExpression Implements IEventAssignmentExpression.HandlerValue
+                Get
+                    Return _statement.Handler
+                End Get
+            End Property
+
+            Public ReadOnly Property IsInvalid As Boolean Implements IOperation.IsInvalid
+                Get
+                    Return _statement.HasErrors
+                End Get
+            End Property
+
+            Public ReadOnly Property Kind As OperationKind Implements IOperation.Kind
+                Get
+                    Return OperationKind.EventAssignmentExpression
+                End Get
+            End Property
+
+            Public ReadOnly Property ResultType As ITypeSymbol Implements IExpression.ResultType
+                Get
+                    Return Nothing
+                End Get
+            End Property
+
+            Public ReadOnly Property Syntax As SyntaxNode Implements IOperation.Syntax
+                Get
+                    Return _statement.Syntax
+                End Get
+            End Property
+        End Class
     End Class
 
     Partial Class BoundAddHandlerStatement
 
-        Protected Overrides ReadOnly Property IAdds As Boolean
+        Protected Overrides ReadOnly Property IExpression As IExpression
             Get
-                Return True
+                Return s_expressionsMappings.GetValue(Me, Function(statement)
+                                                              Return New EventAssignmentExpression(statement, True)
+                                                          End Function)
             End Get
         End Property
     End Class
 
     Partial Class BoundRemoveHandlerStatement
 
-        Protected Overrides ReadOnly Property IAdds As Boolean
+        Protected Overrides ReadOnly Property IExpression As IExpression
             Get
-                Return False
+                Return s_expressionsMappings.GetValue(Me, Function(statement)
+                                                              Return New EventAssignmentExpression(statement, False)
+                                                          End Function)
             End Get
         End Property
     End Class