Implemented C# heirarchy changes discussed in design meeting.

d040c191 · Fredric Silberberg · 2951716a · d040c191 · d040c191 · d040c191
34 changed file
--- a/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
+++ b/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
@@ -268,9 +268,9 @@ private ImmutableArray<IOperation> GetIOperationChildren(BoundNode boundNode)
            return builder.ToImmutableAndFree();
        }

-        private IVariableDeclarationOperation CreateVariableDeclaration(BoundLocalDeclaration boundNode)
+        private ISingleVariableDeclarationOperation CreateVariableDeclaration(BoundLocalDeclaration boundNode)
        {
-            return (IVariableDeclarationOperation)_cache.GetOrAdd(boundNode, n => CreateVariableDeclarationInternal((BoundLocalDeclaration)n, n.Syntax));
+            return (ISingleVariableDeclarationOperation)_cache.GetOrAdd(boundNode, n => CreateVariableDeclarationInternal((BoundLocalDeclaration)n, n.Syntax));
        }

        private IPlaceholderOperation CreateBoundDeconstructValuePlaceholderOperation(BoundDeconstructValuePlaceholder boundDeconstructValuePlaceholder)
@@ -1506,6 +1506,7 @@ private IOperation CreateBoundLocalDeclarationOperation(BoundLocalDeclaration bo

            SyntaxNode varStatement;
            SyntaxNode varDeclaration;
+            SyntaxNode varDeclarator;
            switch (kind)
            {
                case SyntaxKind.LocalDeclarationStatement:
@@ -1516,8 +1517,9 @@ private IOperation CreateBoundLocalDeclarationOperation(BoundLocalDeclaration bo
                    // var statement points to LocalDeclarationStatementSyntax
                    varStatement = statement;

-                    // var declaration points to VariableDeclaratorSyntax
-                    varDeclaration = statement.Declaration.Variables.First();
+                    varDeclaration = statement.Declaration;
+
+                    varDeclarator = statement.Declaration.Variables.First();
                    break;
                }
                case SyntaxKind.VariableDeclarator:
@@ -1526,8 +1528,10 @@ private IOperation CreateBoundLocalDeclarationOperation(BoundLocalDeclaration bo
                    // var statement points to VariableDeclarationSyntax
                    varStatement = node.Parent;

+                    varDeclaration = node.Parent;
+
                    // var declaration points to VariableDeclaratorSyntax
-                    varDeclaration = node;
+                    varDeclarator = node;
                    break;
                }
                default:
@@ -1535,27 +1539,44 @@ private IOperation CreateBoundLocalDeclarationOperation(BoundLocalDeclaration bo
                    Debug.Fail($"Unexpected syntax: {kind}");

                    // otherwise, they points to whatever bound nodes are pointing to.
-                    varStatement = varDeclaration = node;
+                    varStatement = varDeclaration = varDeclarator = node;
                    break;
                }
            }

-            Lazy<ImmutableArray<IVariableDeclarationOperation>> declarations = new Lazy<ImmutableArray<IVariableDeclarationOperation>>(() => ImmutableArray.Create(CreateVariableDeclarationInternal(boundLocalDeclaration, varDeclaration)).CastArray<IVariableDeclarationOperation>());
+            Lazy<ImmutableArray<ISingleVariableDeclarationOperation>> declarations = new Lazy<ImmutableArray<ISingleVariableDeclarationOperation>>(() => ImmutableArray.Create(CreateVariableDeclarationInternal(boundLocalDeclaration, varDeclarator)));
+            // In the case of a for loop, varStatement and varDeclaration will be the same syntax node. We can only have one explicit operation, so make
+            // sure this node is implicit in that scenario
+            bool multiVariableImplicit = (varStatement == varDeclaration) || boundLocalDeclaration.WasCompilerGenerated;
+            // In C#, the MultiVariable initializer will always be null, but we can't pass null as the actual lazy. We assume that all lazy elements always exist
+            Lazy<IVariableInitializerOperation> initializer = new Lazy<IVariableInitializerOperation>(() => null);
+            IMultiVariableDeclarationOperation multiVariableDeclaration = new LazyMultiVariableDeclaration(declarations, initializer, _semanticModel, varDeclaration, null, default, multiVariableImplicit);
            ITypeSymbol type = null;
            Optional<object> constantValue = default(Optional<object>);
            bool isImplicit = boundLocalDeclaration.WasCompilerGenerated;
-            return new LazyVariableDeclarationGroupOperation(declarations, _semanticModel, varStatement, type, constantValue, isImplicit);
+            return new VariableDeclarationGroupOperation(ImmutableArray.Create(multiVariableDeclaration), _semanticModel, varStatement, type, constantValue, isImplicit);
        }

        private IVariableDeclarationGroupOperation CreateBoundMultipleLocalDeclarationsOperation(BoundMultipleLocalDeclarations boundMultipleLocalDeclarations)
        {
-            Lazy<ImmutableArray<IVariableDeclarationOperation>> declarations = new Lazy<ImmutableArray<IVariableDeclarationOperation>>(() =>
-                boundMultipleLocalDeclarations.LocalDeclarations.SelectAsArray(declaration => (IVariableDeclarationOperation)CreateVariableDeclaration(declaration)));
-            SyntaxNode syntax = boundMultipleLocalDeclarations.Syntax;
+            Lazy<ImmutableArray<ISingleVariableDeclarationOperation>> declarations = new Lazy<ImmutableArray<ISingleVariableDeclarationOperation>>(() =>
+                boundMultipleLocalDeclarations.LocalDeclarations.SelectAsArray(declaration => CreateVariableDeclaration(declaration)));
+            // In C#, the MultiVariable initializer will always be null, but we can't pass null as the actual lazy. We assume that all lazy elements always exist
+            Lazy<IVariableInitializerOperation> initializer = new Lazy<IVariableInitializerOperation>(() => null);
+
+            // The syntax for the boundMultipleLocalDeclarations can either be a LocalDeclarationStatement or a VariableDeclaration, depending on the context
+            // (using/fixed/etc statements vs variable declaration). If the former, we make the MultiVariableDeclarationOperation implicit
+            SyntaxNode declarationGroupSyntax = boundMultipleLocalDeclarations.Syntax;
+            SyntaxNode declarationSyntax = declarationGroupSyntax.IsKind(SyntaxKind.LocalDeclarationStatement) ?
+                    ((LocalDeclarationStatementSyntax)declarationGroupSyntax).Declaration :
+                    declarationGroupSyntax;
+            bool declarationIsImplicit = declarationGroupSyntax == declarationSyntax || boundMultipleLocalDeclarations.WasCompilerGenerated;
+            IMultiVariableDeclarationOperation multiVariableDeclaration = new LazyMultiVariableDeclaration(declarations, initializer, _semanticModel, declarationSyntax, null, default, declarationIsImplicit);
+
            ITypeSymbol type = null;
            Optional<object> constantValue = default(Optional<object>);
            bool isImplicit = boundMultipleLocalDeclarations.WasCompilerGenerated;
-            return new LazyVariableDeclarationGroupOperation(declarations, _semanticModel, syntax, type, constantValue, isImplicit);
+            return new VariableDeclarationGroupOperation(ImmutableArray.Create(multiVariableDeclaration), _semanticModel, declarationGroupSyntax, type, constantValue, isImplicit);
        }

        private ILabeledOperation CreateBoundLabelStatementOperation(BoundLabelStatement boundLabelStatement)

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ArrayCreationAndInitializer.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ArrayCreationAndInitializer.cs
@@ -304,17 +304,21 @@ public void F(int dimension)
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int[] x = { 1, 2 };')
-  ISingleVariableDeclarationOperation (Symbol: System.Int32[] x) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'x = { 1, 2 }')
-    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= { 1, 2 }')
-        IArrayCreationOperation (OperationKind.ArrayCreation, Type: System.Int32[]) (Syntax: '{ 1, 2 }')
-          Dimension Sizes(1):
-              ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 2, IsImplicit) (Syntax: '{ 1, 2 }')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'int[] x = { 1, 2 }')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Int32[] x) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'x = { 1, 2 }')
          Initializer: 
-            IArrayInitializerOperation (2 elements) (OperationKind.ArrayInitializer, Type: null) (Syntax: '{ 1, 2 }')
-              Element Values(2):
-                  ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 1) (Syntax: '1')
-                  ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 2) (Syntax: '2')
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= { 1, 2 }')
+              IArrayCreationOperation (OperationKind.ArrayCreation, Type: System.Int32[]) (Syntax: '{ 1, 2 }')
+                Dimension Sizes(1):
+                    ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 2, IsImplicit) (Syntax: '{ 1, 2 }')
+                Initializer: 
+                  IArrayInitializerOperation (2 elements) (OperationKind.ArrayInitializer, Type: null) (Syntax: '{ 1, 2 }')
+                    Element Values(2):
+                        ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 1) (Syntax: '1')
+                        ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 2) (Syntax: '2')
+    Initializer: 
+      null
 ";
            var expectedDiagnostics = DiagnosticDescription.None;


--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IAnonymousFunctionExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IAnonymousFunctionExpression.cs
@@ -31,22 +31,26 @@ static void F()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'Action x = () => F();')
-  ISingleVariableDeclarationOperation (Symbol: System.Action x) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'x = () => F()')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'Action x = () => F()')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Action x) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'x = () => F()')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= () => F()')
+              IDelegateCreationOperation (OperationKind.DelegateCreation, Type: System.Action, IsImplicit) (Syntax: '() => F()')
+                Target: 
+                  IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null) (Syntax: '() => F()')
+                    IBlockOperation (2 statements) (OperationKind.Block, Type: null, IsImplicit) (Syntax: 'F()')
+                      IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsImplicit) (Syntax: 'F()')
+                        Expression: 
+                          IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void) (Syntax: 'F()')
+                            Instance Receiver: 
+                              null
+                            Arguments(0)
+                      IReturnOperation (OperationKind.Return, Type: null, IsImplicit) (Syntax: 'F()')
+                        ReturnedValue: 
+                          null
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= () => F()')
-        IDelegateCreationOperation (OperationKind.DelegateCreation, Type: System.Action, IsImplicit) (Syntax: '() => F()')
-          Target: 
-            IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null) (Syntax: '() => F()')
-              IBlockOperation (2 statements) (OperationKind.Block, Type: null, IsImplicit) (Syntax: 'F()')
-                IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsImplicit) (Syntax: 'F()')
-                  Expression: 
-                    IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void) (Syntax: 'F()')
-                      Instance Receiver: 
-                        null
-                      Arguments(0)
-                IReturnOperation (OperationKind.Return, Type: null, IsImplicit) (Syntax: 'F()')
-                  ReturnedValue: 
-                    null
+      null
 ";
            var expectedDiagnostics = DiagnosticDescription.None;

@@ -111,22 +115,26 @@ static void F()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'Action x =  ... () => F());')
-  ISingleVariableDeclarationOperation (Symbol: System.Action x) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'x = (Action)(() => F())')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'Action x =  ... (() => F())')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Action x) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'x = (Action)(() => F())')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= (Action)(() => F())')
+              IDelegateCreationOperation (OperationKind.DelegateCreation, Type: System.Action) (Syntax: '(Action)(() => F())')
+                Target: 
+                  IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null) (Syntax: '() => F()')
+                    IBlockOperation (2 statements) (OperationKind.Block, Type: null, IsImplicit) (Syntax: 'F()')
+                      IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsImplicit) (Syntax: 'F()')
+                        Expression: 
+                          IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void) (Syntax: 'F()')
+                            Instance Receiver: 
+                              null
+                            Arguments(0)
+                      IReturnOperation (OperationKind.Return, Type: null, IsImplicit) (Syntax: 'F()')
+                        ReturnedValue: 
+                          null
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= (Action)(() => F())')
-        IDelegateCreationOperation (OperationKind.DelegateCreation, Type: System.Action) (Syntax: '(Action)(() => F())')
-          Target: 
-            IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null) (Syntax: '() => F()')
-              IBlockOperation (2 statements) (OperationKind.Block, Type: null, IsImplicit) (Syntax: 'F()')
-                IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsImplicit) (Syntax: 'F()')
-                  Expression: 
-                    IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void) (Syntax: 'F()')
-                      Instance Receiver: 
-                        null
-                      Arguments(0)
-                IReturnOperation (OperationKind.Return, Type: null, IsImplicit) (Syntax: 'F()')
-                  ReturnedValue: 
-                    null
+      null
 ";
            var expectedDiagnostics = DiagnosticDescription.None;

@@ -191,17 +199,21 @@ static void F()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'var x = () => F();')
-  ISingleVariableDeclarationOperation (Symbol: var x) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'x = () => F()')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid) (Syntax: 'var x = () => F()')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: var x) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'x = () => F()')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= () => F()')
+              IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null, IsInvalid) (Syntax: '() => F()')
+                IBlockOperation (1 statements) (OperationKind.Block, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
+                  IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
+                    Expression: 
+                      IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void, IsInvalid) (Syntax: 'F()')
+                        Instance Receiver: 
+                          null
+                        Arguments(0)
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= () => F()')
-        IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null, IsInvalid) (Syntax: '() => F()')
-          IBlockOperation (1 statements) (OperationKind.Block, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
-            IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
-              Expression: 
-                IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void, IsInvalid) (Syntax: 'F()')
-                  Instance Receiver: 
-                    null
-                  Arguments(0)
+      null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS0815: Cannot assign lambda expression to an implicitly-typed variable
@@ -233,19 +245,23 @@ static void F()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'Action<int> ...  () => F();')
-  ISingleVariableDeclarationOperation (Symbol: System.Action<System.Int32> x) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'x = () => F()')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid) (Syntax: 'Action<int> ... = () => F()')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Action<System.Int32> x) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'x = () => F()')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= () => F()')
+              IDelegateCreationOperation (OperationKind.DelegateCreation, Type: System.Action<System.Int32>, IsInvalid, IsImplicit) (Syntax: '() => F()')
+                Target: 
+                  IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null, IsInvalid) (Syntax: '() => F()')
+                    IBlockOperation (1 statements) (OperationKind.Block, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
+                      IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
+                        Expression: 
+                          IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void, IsInvalid) (Syntax: 'F()')
+                            Instance Receiver: 
+                              null
+                            Arguments(0)
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= () => F()')
-        IDelegateCreationOperation (OperationKind.DelegateCreation, Type: System.Action<System.Int32>, IsInvalid, IsImplicit) (Syntax: '() => F()')
-          Target: 
-            IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null, IsInvalid) (Syntax: '() => F()')
-              IBlockOperation (1 statements) (OperationKind.Block, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
-                IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
-                  Expression: 
-                    IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void, IsInvalid) (Syntax: 'F()')
-                      Instance Receiver: 
-                        null
-                      Arguments(0)
+      null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS1593: Delegate 'Action<int>' does not take 0 arguments
@@ -277,25 +293,29 @@ static void F()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'Action<int> ... () => F());')
-  ISingleVariableDeclarationOperation (Symbol: System.Action<System.Int32> x) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'x = (Action)(() => F())')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid) (Syntax: 'Action<int> ... (() => F())')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Action<System.Int32> x) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'x = (Action)(() => F())')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= (Action)(() => F())')
+              IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Action<System.Int32>, IsInvalid, IsImplicit) (Syntax: '(Action)(() => F())')
+                Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
+                Operand: 
+                  IDelegateCreationOperation (OperationKind.DelegateCreation, Type: System.Action, IsInvalid) (Syntax: '(Action)(() => F())')
+                    Target: 
+                      IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null, IsInvalid) (Syntax: '() => F()')
+                        IBlockOperation (2 statements) (OperationKind.Block, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
+                          IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
+                            Expression: 
+                              IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void, IsInvalid) (Syntax: 'F()')
+                                Instance Receiver: 
+                                  null
+                                Arguments(0)
+                          IReturnOperation (OperationKind.Return, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
+                            ReturnedValue: 
+                              null
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= (Action)(() => F())')
-        IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Action<System.Int32>, IsInvalid, IsImplicit) (Syntax: '(Action)(() => F())')
-          Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-          Operand: 
-            IDelegateCreationOperation (OperationKind.DelegateCreation, Type: System.Action, IsInvalid) (Syntax: '(Action)(() => F())')
-              Target: 
-                IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null, IsInvalid) (Syntax: '() => F()')
-                  IBlockOperation (2 statements) (OperationKind.Block, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
-                    IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
-                      Expression: 
-                        IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void, IsInvalid) (Syntax: 'F()')
-                          Instance Receiver: 
-                            null
-                          Arguments(0)
-                    IReturnOperation (OperationKind.Return, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
-                      ReturnedValue: 
-                        null
+      null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS0029: Cannot implicitly convert type 'System.Action' to 'System.Action<int>'
@@ -327,19 +347,23 @@ static void F()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'Action<int> ... () => F());')
-  ISingleVariableDeclarationOperation (Symbol: System.Action<System.Int32> x) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'x = (Action ... (() => F())')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid) (Syntax: 'Action<int> ... (() => F())')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Action<System.Int32> x) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'x = (Action ... (() => F())')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= (Action<i ... (() => F())')
+              IDelegateCreationOperation (OperationKind.DelegateCreation, Type: System.Action<System.Int32>, IsInvalid) (Syntax: '(Action<int>)(() => F())')
+                Target: 
+                  IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null, IsInvalid) (Syntax: '() => F()')
+                    IBlockOperation (1 statements) (OperationKind.Block, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
+                      IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
+                        Expression: 
+                          IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void, IsInvalid) (Syntax: 'F()')
+                            Instance Receiver: 
+                              null
+                            Arguments(0)
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= (Action<i ... (() => F())')
-        IDelegateCreationOperation (OperationKind.DelegateCreation, Type: System.Action<System.Int32>, IsInvalid) (Syntax: '(Action<int>)(() => F())')
-          Target: 
-            IAnonymousFunctionOperation (Symbol: lambda expression) (OperationKind.AnonymousFunction, Type: null, IsInvalid) (Syntax: '() => F()')
-              IBlockOperation (1 statements) (OperationKind.Block, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
-                IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsInvalid, IsImplicit) (Syntax: 'F()')
-                  Expression: 
-                    IInvocationOperation (void Program.F()) (OperationKind.Invocation, Type: System.Void, IsInvalid) (Syntax: 'F()')
-                      Instance Receiver: 
-                        null
-                      Arguments(0)
+      null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS1593: Delegate 'Action<int>' does not take 0 arguments
@@ -378,7 +402,7 @@ static void F()
            var lambdaSyntax = (LambdaExpressionSyntax)variableDeclaration.Declaration.Variables.Single().Initializer.Value;

            var variableDeclarationOperation = (IVariableDeclarationGroupOperation)semanticModel.GetOperationInternal(variableDeclaration);
-            var variableTreeLambdaOperation = (IAnonymousFunctionOperation)variableDeclarationOperation.Declarations.Single().Initializer.Value;
+            var variableTreeLambdaOperation = (IAnonymousFunctionOperation)variableDeclarationOperation.Declarations.Single().Declarations.Single().Initializer.Value;
            var lambdaOperation = (IAnonymousFunctionOperation)semanticModel.GetOperationInternal(lambdaSyntax);

            // Assert that both ways of getting to the lambda (requesting the lambda directly, and requesting via the lambda syntax)
@@ -386,7 +410,7 @@ static void F()
            Assert.Same(variableTreeLambdaOperation, lambdaOperation);

            var variableDeclarationOperationSecondRequest = (IVariableDeclarationGroupOperation)semanticModel.GetOperationInternal(variableDeclaration);
-            var variableTreeLambdaOperationSecondRequest = (IAnonymousFunctionOperation)variableDeclarationOperation.Declarations.Single().Initializer.Value;
+            var variableTreeLambdaOperationSecondRequest = (IAnonymousFunctionOperation)variableDeclarationOperation.Declarations.Single().Declarations.Single(). Initializer.Value;
            var lambdaOperationSecondRequest = (IAnonymousFunctionOperation)semanticModel.GetOperationInternal(lambdaSyntax);

            // Assert that, when request the variable declaration or the lambda for a second time, there is no rebinding of the

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IAwaitExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IAwaitExpression.cs
@@ -201,7 +201,11 @@ static void M(Task<int> t)
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'await t;')
-  ISingleVariableDeclarationOperation (Symbol: await t) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 't')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid) (Syntax: 'await t')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: await t) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 't')
+          Initializer: 
+            null
    Initializer: 
      null
 ";

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs
@@ -355,7 +355,7 @@ static void Main(string[] args)
                    },
                    OperationSelector = (operation) =>
                    {
-                        var initializer = ((IVariableDeclarationOperation)operation).Initializer.Value;
+                        var initializer = ((ISingleVariableDeclarationOperation)operation).Initializer.Value;
                        return (IConversionOperation)((ICoalesceOperation)initializer).WhenNull;
                    }
                }.Verify);
@@ -3208,13 +3208,17 @@ static void M1()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'object o = null;')
-  ISingleVariableDeclarationOperation (Symbol: System.Object o) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'o = null')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'object o = null')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Object o) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'o = null')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= null')
+              IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Object, Constant: null, IsImplicit) (Syntax: 'null')
+                Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: True, IsUserDefined: False) (MethodSymbol: null)
+                Operand: 
+                  ILiteralOperation (OperationKind.Literal, Type: null, Constant: null) (Syntax: 'null')
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= null')
-        IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Object, Constant: null, IsImplicit) (Syntax: 'null')
-          Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: True, IsUserDefined: False) (MethodSymbol: null)
-          Operand: 
-            ILiteralOperation (OperationKind.Literal, Type: null, Constant: null) (Syntax: 'null')
+      null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS0219: The variable 'o' is assigned but its value is never used
@@ -3242,13 +3246,17 @@ void Main()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'Action<stri ... jectAction;')
-  ISingleVariableDeclarationOperation (Symbol: System.Action<System.String> stringAction) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'stringActio ... bjectAction')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'Action<stri ... bjectAction')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Action<System.String> stringAction) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'stringActio ... bjectAction')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= objectAction')
+              IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Action<System.String>, IsImplicit) (Syntax: 'objectAction')
+                Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: True, IsUserDefined: False) (MethodSymbol: null)
+                Operand: 
+                  ILocalReferenceOperation: objectAction (OperationKind.LocalReference, Type: System.Action<System.Object>) (Syntax: 'objectAction')
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= objectAction')
-        IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Action<System.String>, IsImplicit) (Syntax: 'objectAction')
-          Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: True, IsUserDefined: False) (MethodSymbol: null)
-          Operand: 
-            ILocalReferenceOperation: objectAction (OperationKind.LocalReference, Type: System.Action<System.Object>) (Syntax: 'objectAction')
+      null
 ";
            var expectedDiagnostics = DiagnosticDescription.None;

@@ -3272,13 +3280,17 @@ void Main()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'Action<int> ... jectAction;')
-  ISingleVariableDeclarationOperation (Symbol: System.Action<System.Int32> intAction) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'intAction = objectAction')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid) (Syntax: 'Action<int> ... bjectAction')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Action<System.Int32> intAction) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'intAction = objectAction')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= objectAction')
+              IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Action<System.Int32>, IsInvalid, IsImplicit) (Syntax: 'objectAction')
+                Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
+                Operand: 
+                  ILocalReferenceOperation: objectAction (OperationKind.LocalReference, Type: System.Action<System.Object>, IsInvalid) (Syntax: 'objectAction')
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= objectAction')
-        IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Action<System.Int32>, IsInvalid, IsImplicit) (Syntax: 'objectAction')
-          Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-          Operand: 
-            ILocalReferenceOperation: objectAction (OperationKind.LocalReference, Type: System.Action<System.Object>, IsInvalid) (Syntax: 'objectAction')
+      null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS0029: Cannot implicitly convert type 'System.Action<object>' to 'System.Action<int>'
@@ -4938,13 +4950,17 @@ static void M1()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'object o = (object)null;')
-  ISingleVariableDeclarationOperation (Symbol: System.Object o) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'o = (object)null')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'object o = (object)null')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Object o) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'o = (object)null')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= (object)null')
+              IConversionOperation (Explicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Object, Constant: null) (Syntax: '(object)null')
+                Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: True, IsUserDefined: False) (MethodSymbol: null)
+                Operand: 
+                  ILiteralOperation (OperationKind.Literal, Type: null, Constant: null) (Syntax: 'null')
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= (object)null')
-        IConversionOperation (Explicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Object, Constant: null) (Syntax: '(object)null')
-          Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: True, IsUserDefined: False) (MethodSymbol: null)
-          Operand: 
-            ILiteralOperation (OperationKind.Literal, Type: null, Constant: null) (Syntax: 'null')
+      null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS0219: The variable 'o' is assigned but its value is never used
@@ -5025,8 +5041,11 @@ private class ExpectedSymbolVerifier
            public static IOperation IVariableDeclarationStatementSelector(IOperation operation) =>
                ((IVariableDeclarationGroupOperation)operation).Declarations.Single().Initializer;

-            public static IOperation IVariableDeclarationSelector(IOperation operation) =>
-                ((IVariableDeclarationOperation)operation).Initializer.Value;
+            public static IOperation IMultiVariableDeclarationSelector(IOperation operation) =>
+                ((IMultiVariableDeclarationOperation)operation).Initializer.Value;
+
+            public static IOperation ISingleVariableDeclarationSelector(IOperation operation) =>
+                ((ISingleVariableDeclarationOperation)operation).Initializer.Value;

            public static IOperation IReturnDeclarationStatementSelector(IOperation operation) =>
                ((IReturnOperation)operation).ReturnedValue;
@@ -5108,8 +5127,10 @@ private IOperation GetAndInvokeOperationSelector(IOperation operation)
                {
                    case IVariableDeclarationGroupOperation _:
                        return IVariableDeclarationStatementSelector(operation);
-                    case IVariableDeclarationOperation _:
-                        return IVariableDeclarationSelector(operation);
+                    case IMultiVariableDeclarationOperation _:
+                        return IMultiVariableDeclarationSelector(operation);
+                    case ISingleVariableDeclarationOperation _:
+                        return ISingleVariableDeclarationSelector(operation);
                    case IReturnOperation _:
                        return IReturnDeclarationStatementSelector(operation);
                    case IConversionOperation conv:

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IDelegateCreationExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IDelegateCreationExpression.cs
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IFixedStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IFixedStatement.cs
@@ -36,16 +36,20 @@ void M1()
 IOperation:  (OperationKind.None, Type: null) (Syntax: 'fixed(int * ... }')
  Children(2):
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int *p = &i')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32* p) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p = &i')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsImplicit) (Syntax: 'int *p = &i')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32* p) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p = &i')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i')
+                    IOperation:  (OperationKind.None, Type: null) (Syntax: '&i')
+                      Children(1):
+                          IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i')
+                            Reference: 
+                              IFieldReferenceOperation: System.Int32 C.i (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i')
+                                Instance Receiver: 
+                                  IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i')
-              IOperation:  (OperationKind.None, Type: null) (Syntax: '&i')
-                Children(1):
-                    IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i')
-                      Reference: 
-                        IFieldReferenceOperation: System.Int32 C.i (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i')
-                          Instance Receiver: 
-                            IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i')
+            null
      IBlockOperation (1 statements) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
        IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null) (Syntax: 'Console.Wri ...  is {*p}"");')
          Expression: 
@@ -105,27 +109,31 @@ void M1()
            string expectedOperationTree = @"
 IOperation:  (OperationKind.None, Type: null) (Syntax: 'fixed (int* ... }')
  Children(2):
-      IVariableDeclarationGroupOperation (2 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int* p1 = &i1, p2 = &i2')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32* p1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p1 = &i1')
-          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i1')
-              IOperation:  (OperationKind.None, Type: null) (Syntax: '&i1')
-                Children(1):
-                    IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i1')
-                      Reference: 
-                        IFieldReferenceOperation: System.Int32 C.i1 (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i1')
-                          Instance Receiver: 
-                            IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i1')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32* p2) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p2 = &i2')
+      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int* p1 = &i1, p2 = &i2')
+        IMultiVariableDeclarationOperation (2 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsImplicit) (Syntax: 'int* p1 = &i1, p2 = &i2')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32* p1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p1 = &i1')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i1')
+                    IOperation:  (OperationKind.None, Type: null) (Syntax: '&i1')
+                      Children(1):
+                          IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i1')
+                            Reference: 
+                              IFieldReferenceOperation: System.Int32 C.i1 (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i1')
+                                Instance Receiver: 
+                                  IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i1')
+              ISingleVariableDeclarationOperation (Symbol: System.Int32* p2) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p2 = &i2')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i2')
+                    IOperation:  (OperationKind.None, Type: null) (Syntax: '&i2')
+                      Children(1):
+                          IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i2')
+                            Reference: 
+                              IFieldReferenceOperation: System.Int32 C.i2 (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i2')
+                                Instance Receiver: 
+                                  IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i2')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i2')
-              IOperation:  (OperationKind.None, Type: null) (Syntax: '&i2')
-                Children(1):
-                    IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i2')
-                      Reference: 
-                        IFieldReferenceOperation: System.Int32 C.i2 (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i2')
-                          Instance Receiver: 
-                            IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i2')
+            null
      IBlockOperation (1 statements) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
        IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null) (Syntax: 'i3 = *p1 + *p2;')
          Expression: 
@@ -181,29 +189,37 @@ void M1()
 IOperation:  (OperationKind.None, Type: null) (Syntax: 'fixed (int* ... }')
  Children(2):
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int* p1 = &i1')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32* p1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p1 = &i1')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsImplicit) (Syntax: 'int* p1 = &i1')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32* p1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p1 = &i1')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i1')
+                    IOperation:  (OperationKind.None, Type: null) (Syntax: '&i1')
+                      Children(1):
+                          IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i1')
+                            Reference: 
+                              IFieldReferenceOperation: System.Int32 C.i1 (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i1')
+                                Instance Receiver: 
+                                  IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i1')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i1')
-              IOperation:  (OperationKind.None, Type: null) (Syntax: '&i1')
-                Children(1):
-                    IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i1')
-                      Reference: 
-                        IFieldReferenceOperation: System.Int32 C.i1 (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i1')
-                          Instance Receiver: 
-                            IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i1')
+            null
      IOperation:  (OperationKind.None, Type: null) (Syntax: 'fixed (int* ... }')
        Children(2):
            IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int* p2 = &i2')
-              ISingleVariableDeclarationOperation (Symbol: System.Int32* p2) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p2 = &i2')
+              IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsImplicit) (Syntax: 'int* p2 = &i2')
+                Declarations:
+                    ISingleVariableDeclarationOperation (Symbol: System.Int32* p2) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p2 = &i2')
+                      Initializer: 
+                        IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i2')
+                          IOperation:  (OperationKind.None, Type: null) (Syntax: '&i2')
+                            Children(1):
+                                IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i2')
+                                  Reference: 
+                                    IFieldReferenceOperation: System.Int32 C.i2 (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i2')
+                                      Instance Receiver: 
+                                        IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i2')
                Initializer: 
-                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i2')
-                    IOperation:  (OperationKind.None, Type: null) (Syntax: '&i2')
-                      Children(1):
-                          IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i2')
-                            Reference: 
-                              IFieldReferenceOperation: System.Int32 C.i2 (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i2')
-                                Instance Receiver: 
-                                  IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i2')
+                  null
            IBlockOperation (1 statements) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
              IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null) (Syntax: 'i3 = *p1 + *p2;')
                Expression: 
@@ -254,11 +270,15 @@ void M1()
 IOperation:  (OperationKind.None, Type: null, IsInvalid) (Syntax: 'fixed (int* ... }')
  Children(2):
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'int* p1 =')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32* p1) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'p1 =')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid, IsImplicit) (Syntax: 'int* p1 =')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32* p1) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'p1 =')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '=')
+                    IInvalidOperation (OperationKind.Invalid, Type: null, IsInvalid) (Syntax: '')
+                      Children(0)
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '=')
-              IInvalidOperation (OperationKind.Invalid, Type: null, IsInvalid) (Syntax: '')
-                Children(0)
+            null
      IBlockOperation (1 statements) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
        IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null) (Syntax: 'i3 = *p1;')
          Expression: 
@@ -308,16 +328,20 @@ void M1()
 IOperation:  (OperationKind.None, Type: null, IsInvalid) (Syntax: 'fixed (int* ... }')
  Children(2):
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int* p1 = &i1')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32* p1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p1 = &i1')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsImplicit) (Syntax: 'int* p1 = &i1')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32* p1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'p1 = &i1')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i1')
+                    IOperation:  (OperationKind.None, Type: null) (Syntax: '&i1')
+                      Children(1):
+                          IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i1')
+                            Reference: 
+                              IFieldReferenceOperation: System.Int32 C.i1 (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i1')
+                                Instance Receiver: 
+                                  IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i1')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= &i1')
-              IOperation:  (OperationKind.None, Type: null) (Syntax: '&i1')
-                Children(1):
-                    IAddressOfOperation (OperationKind.AddressOf, Type: System.Int32*) (Syntax: '&i1')
-                      Reference: 
-                        IFieldReferenceOperation: System.Int32 C.i1 (OperationKind.FieldReference, Type: System.Int32) (Syntax: 'i1')
-                          Instance Receiver: 
-                            IInstanceReferenceOperation (OperationKind.InstanceReference, Type: C, IsImplicit) (Syntax: 'i1')
+            null
      IBlockOperation (1 statements) (OperationKind.Block, Type: null, IsInvalid) (Syntax: '{ ... }')
        IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null, IsInvalid) (Syntax: 'i3 = &p1;')
          Expression: 

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.cs
@@ -584,20 +584,24 @@ static void Main()
    IBlockOperation (1 statements, 1 locals) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      Locals: Local_1: System.Boolean b
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'bool b = !x ... uals(null);')
-        ISingleVariableDeclarationOperation (Symbol: System.Boolean b) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'b = !x.Equals(null)')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'bool b = !x.Equals(null)')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Boolean b) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'b = !x.Equals(null)')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= !x.Equals(null)')
+                    IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Boolean, IsImplicit) (Syntax: '!x.Equals(null)')
+                      Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
+                      Operand: 
+                        IUnaryOperation (UnaryOperatorKind.Not) (OperationKind.UnaryOperator, Type: System.Object) (Syntax: '!x.Equals(null)')
+                          Operand: 
+                            IInvalidOperation (OperationKind.Invalid, Type: ?) (Syntax: 'x.Equals(null)')
+                              Children(2):
+                                  IOperation:  (OperationKind.None, Type: null) (Syntax: 'x.Equals')
+                                    Children(1):
+                                        ILocalReferenceOperation: x (OperationKind.LocalReference, Type: MissingType) (Syntax: 'x')
+                                  ILiteralOperation (OperationKind.Literal, Type: null, Constant: null) (Syntax: 'null')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= !x.Equals(null)')
-              IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.Boolean, IsImplicit) (Syntax: '!x.Equals(null)')
-                Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                Operand: 
-                  IUnaryOperation (UnaryOperatorKind.Not) (OperationKind.UnaryOperator, Type: System.Object) (Syntax: '!x.Equals(null)')
-                    Operand: 
-                      IInvalidOperation (OperationKind.Invalid, Type: ?) (Syntax: 'x.Equals(null)')
-                        Children(2):
-                            IOperation:  (OperationKind.None, Type: null) (Syntax: 'x.Equals')
-                              Children(1):
-                                  ILocalReferenceOperation: x (OperationKind.LocalReference, Type: MissingType) (Syntax: 'x')
-                            ILiteralOperation (OperationKind.Literal, Type: null, Constant: null) (Syntax: 'null')
+            null
  NextVariables(0)
 ";
            VerifyOperationTreeForTest<ForEachStatementSyntax>(source, expectedOperationTree);

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IObjectCreationExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IObjectCreationExpression.cs
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ITupleExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ITupleExpression.cs
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IUsingStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IUsingStatement.cs
@@ -34,13 +34,17 @@ public static void M1()
 IUsingOperation (OperationKind.Using, Type: null) (Syntax: 'using (var  ... }')
  Resources: 
    IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'var c = new C()')
-      ISingleVariableDeclarationOperation (Symbol: C c) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c = new C()')
-        Initializer: 
-          IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
-            IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
-              Arguments(0)
+      IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsImplicit) (Syntax: 'var c = new C()')
+        Declarations:
+            ISingleVariableDeclarationOperation (Symbol: C c) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c = new C()')
              Initializer: 
-                null
+                IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
+                  IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
+                    Arguments(0)
+                    Initializer: 
+                      null
+        Initializer: 
+          null
  Body: 
    IBlockOperation (1 statements) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null) (Syntax: 'Console.Wri ... oString());')
@@ -88,21 +92,25 @@ public static void M1()
            string expectedOperationTree = @"
 IUsingOperation (OperationKind.Using, Type: null) (Syntax: 'using (C c1 ... }')
  Resources: 
-    IVariableDeclarationGroupOperation (2 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'C c1 = new  ... 2 = new C()')
-      ISingleVariableDeclarationOperation (Symbol: C c1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c1 = new C()')
-        Initializer: 
-          IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
-            IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
-              Arguments(0)
+    IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'C c1 = new  ... 2 = new C()')
+      IMultiVariableDeclarationOperation (2 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsImplicit) (Syntax: 'C c1 = new  ... 2 = new C()')
+        Declarations:
+            ISingleVariableDeclarationOperation (Symbol: C c1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c1 = new C()')
              Initializer: 
-                null
-      ISingleVariableDeclarationOperation (Symbol: C c2) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c2 = new C()')
-        Initializer: 
-          IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
-            IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
-              Arguments(0)
+                IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
+                  IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
+                    Arguments(0)
+                    Initializer: 
+                      null
+            ISingleVariableDeclarationOperation (Symbol: C c2) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c2 = new C()')
              Initializer: 
-                null
+                IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
+                  IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
+                    Arguments(0)
+                    Initializer: 
+                      null
+        Initializer: 
+          null
  Body: 
    IBlockOperation (1 statements) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null) (Syntax: 'Console.Wri ... oString());')
@@ -199,24 +207,32 @@ public static void M1()
 IUsingOperation (OperationKind.Using, Type: null) (Syntax: 'using (var  ... }')
  Resources: 
    IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'var c1 = new C()')
-      ISingleVariableDeclarationOperation (Symbol: C c1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c1 = new C()')
-        Initializer: 
-          IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
-            IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
-              Arguments(0)
+      IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsImplicit) (Syntax: 'var c1 = new C()')
+        Declarations:
+            ISingleVariableDeclarationOperation (Symbol: C c1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c1 = new C()')
              Initializer: 
-                null
+                IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
+                  IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
+                    Arguments(0)
+                    Initializer: 
+                      null
+        Initializer: 
+          null
  Body: 
    IUsingOperation (OperationKind.Using, Type: null) (Syntax: 'using (var  ... }')
      Resources: 
        IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'var c2 = new C()')
-          ISingleVariableDeclarationOperation (Symbol: C c2) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c2 = new C()')
-            Initializer: 
-              IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
-                IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
-                  Arguments(0)
+          IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsImplicit) (Syntax: 'var c2 = new C()')
+            Declarations:
+                ISingleVariableDeclarationOperation (Symbol: C c2) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c2 = new C()')
                  Initializer: 
-                    null
+                    IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
+                      IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
+                        Arguments(0)
+                        Initializer: 
+                          null
+            Initializer: 
+              null
      Body: 
        IBlockOperation (1 statements) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
          IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null) (Syntax: 'Console.Wri ... oString());')
@@ -331,21 +347,25 @@ public static void M1()
            string expectedOperationTree = @"
 IUsingOperation (OperationKind.Using, Type: null, IsInvalid) (Syntax: 'using (var  ... }')
  Resources: 
-    IVariableDeclarationGroupOperation (2 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'var c1 = ne ... 2 = new C()')
-      ISingleVariableDeclarationOperation (Symbol: C c1) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'c1 = new C()')
-        Initializer: 
-          IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= new C()')
-            IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C, IsInvalid) (Syntax: 'new C()')
-              Arguments(0)
+    IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'var c1 = ne ... 2 = new C()')
+      IMultiVariableDeclarationOperation (2 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid, IsImplicit) (Syntax: 'var c1 = ne ... 2 = new C()')
+        Declarations:
+            ISingleVariableDeclarationOperation (Symbol: C c1) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'c1 = new C()')
              Initializer: 
-                null
-      ISingleVariableDeclarationOperation (Symbol: C c2) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'c2 = new C()')
-        Initializer: 
-          IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= new C()')
-            IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C, IsInvalid) (Syntax: 'new C()')
-              Arguments(0)
+                IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= new C()')
+                  IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C, IsInvalid) (Syntax: 'new C()')
+                    Arguments(0)
+                    Initializer: 
+                      null
+            ISingleVariableDeclarationOperation (Symbol: C c2) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'c2 = new C()')
              Initializer: 
-                null
+                IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= new C()')
+                  IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C, IsInvalid) (Syntax: 'new C()')
+                    Arguments(0)
+                    Initializer: 
+                      null
+        Initializer: 
+          null
  Body: 
    IBlockOperation (1 statements) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null) (Syntax: 'Console.Wri ... oString());')
@@ -409,21 +429,29 @@ public static void M1()
  Locals: Local_1: C c1
    Local_2: C c2
  IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'var c1 = new C();')
-    ISingleVariableDeclarationOperation (Symbol: C c1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c1 = new C()')
-      Initializer: 
-        IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
-          IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
-            Arguments(0)
+    IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'var c1 = new C()')
+      Declarations:
+          ISingleVariableDeclarationOperation (Symbol: C c1) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c1 = new C()')
            Initializer: 
-              null
-  IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'var c2 = new C();')
-    ISingleVariableDeclarationOperation (Symbol: C c2) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c2 = new C()')
+              IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
+                IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
+                  Arguments(0)
+                  Initializer: 
+                    null
      Initializer: 
-        IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
-          IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
-            Arguments(0)
+        null
+  IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'var c2 = new C();')
+    IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'var c2 = new C()')
+      Declarations:
+          ISingleVariableDeclarationOperation (Symbol: C c2) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c2 = new C()')
            Initializer: 
-              null
+              IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
+                IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
+                  Arguments(0)
+                  Initializer: 
+                    null
+      Initializer: 
+        null
  IUsingOperation (OperationKind.Using, Type: null, IsInvalid) (Syntax: 'using (c1')
    Resources: 
      ILocalReferenceOperation: c1 (OperationKind.LocalReference, Type: C, IsInvalid) (Syntax: 'c1')
@@ -504,13 +532,17 @@ public static void M1()
 IUsingOperation (OperationKind.Using, Type: null, IsInvalid) (Syntax: 'using (var  ... }')
  Resources: 
    IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'var c1 = new C()')
-      ISingleVariableDeclarationOperation (Symbol: C c1) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'c1 = new C()')
-        Initializer: 
-          IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= new C()')
-            IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C, IsInvalid) (Syntax: 'new C()')
-              Arguments(0)
+      IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid, IsImplicit) (Syntax: 'var c1 = new C()')
+        Declarations:
+            ISingleVariableDeclarationOperation (Symbol: C c1) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'c1 = new C()')
              Initializer: 
-                null
+                IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= new C()')
+                  IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C, IsInvalid) (Syntax: 'new C()')
+                    Arguments(0)
+                    Initializer: 
+                      null
+        Initializer: 
+          null
  Body: 
    IBlockOperation (1 statements) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      IExpressionStatementOperation (OperationKind.ExpressionStatement, Type: null) (Syntax: 'Console.Wri ... oString());')
@@ -758,13 +790,17 @@ public static void M1()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'var c = new C()')
-  ISingleVariableDeclarationOperation (Symbol: C c) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c = new C()')
-    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
-        IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
-          Arguments(0)
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsImplicit) (Syntax: 'var c = new C()')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: C c) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'c = new C()')
          Initializer: 
-            null
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= new C()')
+              IObjectCreationOperation (Constructor: C..ctor()) (OperationKind.ObjectCreation, Type: C) (Syntax: 'new C()')
+                Arguments(0)
+                Initializer: 
+                  null
+    Initializer: 
+      null
 ";
            var expectedDiagnostics = DiagnosticDescription.None;


--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IVariableDeclaration.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IVariableDeclaration.cs
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.cs
@@ -145,12 +145,16 @@ static void Main()
    IBlockOperation (2 statements, 1 locals) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      Locals: Local_1: System.Int32 value
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int value = ++index;')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32 value) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'value = ++index')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'int value = ++index')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32 value) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'value = ++index')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= ++index')
+                    IIncrementOrDecrementOperation (Prefix) (OperationKind.Increment, Type: System.Int32) (Syntax: '++index')
+                      Target: 
+                        ILocalReferenceOperation: index (OperationKind.LocalReference, Type: System.Int32) (Syntax: 'index')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= ++index')
-              IIncrementOrDecrementOperation (Prefix) (OperationKind.Increment, Type: System.Int32) (Syntax: '++index')
-                Target: 
-                  ILocalReferenceOperation: index (OperationKind.LocalReference, Type: System.Int32) (Syntax: 'index')
+            null
      IConditionalOperation (OperationKind.Conditional, Type: null) (Syntax: 'if (value > ... }')
        Condition: 
          IBinaryOperation (BinaryOperatorKind.GreaterThan) (OperationKind.BinaryOperator, Type: System.Boolean) (Syntax: 'value > 10')
@@ -206,12 +210,16 @@ static void Main()
    IBlockOperation (3 statements, 1 locals) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      Locals: Local_1: System.Int32 value
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int value = ++index;')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32 value) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'value = ++index')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'int value = ++index')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32 value) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'value = ++index')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= ++index')
+                    IIncrementOrDecrementOperation (Prefix) (OperationKind.Increment, Type: System.Int32) (Syntax: '++index')
+                      Target: 
+                        ILocalReferenceOperation: index (OperationKind.LocalReference, Type: System.Int32) (Syntax: 'index')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= ++index')
-              IIncrementOrDecrementOperation (Prefix) (OperationKind.Increment, Type: System.Int32) (Syntax: '++index')
-                Target: 
-                  ILocalReferenceOperation: index (OperationKind.LocalReference, Type: System.Int32) (Syntax: 'index')
+            null
      IConditionalOperation (OperationKind.Conditional, Type: null) (Syntax: 'if (value > ... }')
        Condition: 
          IBinaryOperation (BinaryOperatorKind.GreaterThan) (OperationKind.BinaryOperator, Type: System.Boolean) (Syntax: 'value > 5')
@@ -280,12 +288,16 @@ static void Main()
    IBlockOperation (3 statements, 1 locals) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      Locals: Local_1: System.Int32 value
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int value = ++index;')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32 value) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'value = ++index')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'int value = ++index')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32 value) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'value = ++index')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= ++index')
+                    IIncrementOrDecrementOperation (Prefix) (OperationKind.Increment, Type: System.Int32) (Syntax: '++index')
+                      Target: 
+                        ILocalReferenceOperation: index (OperationKind.LocalReference, Type: System.Int32) (Syntax: 'index')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= ++index')
-              IIncrementOrDecrementOperation (Prefix) (OperationKind.Increment, Type: System.Int32) (Syntax: '++index')
-                Target: 
-                  ILocalReferenceOperation: index (OperationKind.LocalReference, Type: System.Int32) (Syntax: 'index')
+            null
      IConditionalOperation (OperationKind.Conditional, Type: null) (Syntax: 'if (value > ... }')
        Condition: 
          IBinaryOperation (BinaryOperatorKind.GreaterThan) (OperationKind.BinaryOperator, Type: System.Boolean) (Syntax: 'value > 100')
@@ -571,12 +583,16 @@ static void Main()
    IBlockOperation (2 statements, 1 locals) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      Locals: Local_1: System.Int32 value
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int value = ++index;')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32 value) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'value = ++index')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'int value = ++index')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32 value) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'value = ++index')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= ++index')
+                    IIncrementOrDecrementOperation (Prefix) (OperationKind.Increment, Type: System.Int32) (Syntax: '++index')
+                      Target: 
+                        ILocalReferenceOperation: index (OperationKind.LocalReference, Type: System.Int32) (Syntax: 'index')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= ++index')
-              IIncrementOrDecrementOperation (Prefix) (OperationKind.Increment, Type: System.Int32) (Syntax: '++index')
-                Target: 
-                  ILocalReferenceOperation: index (OperationKind.LocalReference, Type: System.Int32) (Syntax: 'index')
+            null
      IConditionalOperation (OperationKind.Conditional, Type: null) (Syntax: 'if (value > ... }')
        Condition: 
          IBinaryOperation (BinaryOperatorKind.GreaterThan) (OperationKind.BinaryOperator, Type: System.Boolean) (Syntax: 'value > 100')
@@ -734,10 +750,14 @@ static void Main()
            Target: 
              ILocalReferenceOperation: i (OperationKind.LocalReference, Type: System.Int32) (Syntax: 'i')
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int j = 0;')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32 j) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'j = 0')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'int j = 0')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32 j) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'j = 0')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= 0')
+                    ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 0) (Syntax: '0')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= 0')
-              ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 0) (Syntax: '0')
+            null
      IWhileLoopOperation (LoopKind.While) (OperationKind.Loop, Type: null) (Syntax: 'while (j <  ... }')
        Condition: 
          IBinaryOperation (BinaryOperatorKind.LessThan) (OperationKind.BinaryOperator, Type: System.Boolean) (Syntax: 'j < 10')
@@ -818,10 +838,14 @@ static void Main()
            Target: 
              ILocalReferenceOperation: i (OperationKind.LocalReference, Type: System.Int32) (Syntax: 'i')
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int j = 0;')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32 j) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'j = 0')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'int j = 0')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32 j) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'j = 0')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= 0')
+                    ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 0) (Syntax: '0')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= 0')
-              ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 0) (Syntax: '0')
+            null
      IWhileLoopOperation (LoopKind.While) (OperationKind.Loop, Type: null) (Syntax: 'while (j <  ... }')
        Condition: 
          IBinaryOperation (BinaryOperatorKind.LessThan) (OperationKind.BinaryOperator, Type: System.Boolean) (Syntax: 'j < 10')

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_InvalidExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_InvalidExpression.cs
@@ -172,15 +172,19 @@ void F()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'string y = x.i1;')
-  ISingleVariableDeclarationOperation (Symbol: System.String y) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'y = x.i1')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid) (Syntax: 'string y = x.i1')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.String y) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'y = x.i1')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= x.i1')
+              IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.String, IsInvalid, IsImplicit) (Syntax: 'x.i1')
+                Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
+                Operand: 
+                  IFieldReferenceOperation: System.Int32 Program.i1 (OperationKind.FieldReference, Type: System.Int32, IsInvalid) (Syntax: 'x.i1')
+                    Instance Receiver: 
+                      ILocalReferenceOperation: x (OperationKind.LocalReference, Type: Program, IsInvalid) (Syntax: 'x')
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= x.i1')
-        IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: System.String, IsInvalid, IsImplicit) (Syntax: 'x.i1')
-          Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-          Operand: 
-            IFieldReferenceOperation: System.Int32 Program.i1 (OperationKind.FieldReference, Type: System.Int32, IsInvalid) (Syntax: 'x.i1')
-              Instance Receiver: 
-                ILocalReferenceOperation: x (OperationKind.LocalReference, Type: Program, IsInvalid) (Syntax: 'x')
+      null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS0029: Cannot implicitly convert type 'int' to 'string'
@@ -217,15 +221,19 @@ void F()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'Program y = ... ogram)x.i1;')
-  ISingleVariableDeclarationOperation (Symbol: Program y) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'y = (Program)x.i1')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid) (Syntax: 'Program y = ... rogram)x.i1')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: Program y) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: 'y = (Program)x.i1')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= (Program)x.i1')
+              IConversionOperation (Explicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: Program, IsInvalid) (Syntax: '(Program)x.i1')
+                Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
+                Operand: 
+                  IFieldReferenceOperation: System.Int32 Program.i1 (OperationKind.FieldReference, Type: System.Int32, IsInvalid) (Syntax: 'x.i1')
+                    Instance Receiver: 
+                      ILocalReferenceOperation: x (OperationKind.LocalReference, Type: Program, IsInvalid) (Syntax: 'x')
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= (Program)x.i1')
-        IConversionOperation (Explicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: Program, IsInvalid) (Syntax: '(Program)x.i1')
-          Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-          Operand: 
-            IFieldReferenceOperation: System.Int32 Program.i1 (OperationKind.FieldReference, Type: System.Int32, IsInvalid) (Syntax: 'x.i1')
-              Instance Receiver: 
-                ILocalReferenceOperation: x (OperationKind.LocalReference, Type: Program, IsInvalid) (Syntax: 'x')
+      null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS0030: Cannot convert type 'int' to 'Program'

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_InvalidStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_InvalidStatement.cs
@@ -27,11 +27,15 @@ static void Main(string[] args)
 }
 ";
            string expectedOperationTree = @"
-IVariableDeclarationGroupOperation (2 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'int x, ( 1 );')
-  ISingleVariableDeclarationOperation (Symbol: System.Int32 x) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'x')
-    Initializer: 
-      null
-  ISingleVariableDeclarationOperation (Symbol: System.Int32 ) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: '( 1 ')
+IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'int x, ( 1 );')
+  IMultiVariableDeclarationOperation (2 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid) (Syntax: 'int x, ( 1 ')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: System.Int32 x) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'x')
+          Initializer: 
+            null
+        ISingleVariableDeclarationOperation (Symbol: System.Int32 ) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: '( 1 ')
+          Initializer: 
+            null
    Initializer: 
      null
 ";

--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_TryCatch.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_TryCatch.cs
@@ -532,10 +532,14 @@ static void M(string s)
    IBlockOperation (1 statements, 1 locals) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      Locals: Local_1: System.Int32 i
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int i = 0;')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32 i) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'i = 0')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'int i = 0')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32 i) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'i = 0')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= 0')
+                    ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 0) (Syntax: '0')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= 0')
-              ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 0) (Syntax: '0')
+            null
  Catch clauses(1):
      ICatchClauseOperation (Exception type: System.Exception) (OperationKind.CatchClause, Type: null) (Syntax: 'catch (Exce ... }')
        ExceptionDeclarationOrExpression: 
@@ -591,10 +595,14 @@ static void M(string s)
          IBlockOperation (1 statements, 1 locals) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
            Locals: Local_1: System.Int32 i
            IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int i = 0;')
-              ISingleVariableDeclarationOperation (Symbol: System.Int32 i) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'i = 0')
+              IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'int i = 0')
+                Declarations:
+                    ISingleVariableDeclarationOperation (Symbol: System.Int32 i) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'i = 0')
+                      Initializer: 
+                        IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= 0')
+                          ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 0) (Syntax: '0')
                Initializer: 
-                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= 0')
-                    ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 0) (Syntax: '0')
+                  null
  Finally: 
    null
 ";
@@ -732,10 +740,14 @@ Catch clauses(0)
    IBlockOperation (1 statements, 1 locals) (OperationKind.Block, Type: null) (Syntax: '{ ... }')
      Locals: Local_1: System.Int32 i
      IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null) (Syntax: 'int i = 0;')
-        ISingleVariableDeclarationOperation (Symbol: System.Int32 i) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'i = 0')
+        IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null) (Syntax: 'int i = 0')
+          Declarations:
+              ISingleVariableDeclarationOperation (Symbol: System.Int32 i) (OperationKind.SingleVariableDeclaration, Type: null) (Syntax: 'i = 0')
+                Initializer: 
+                  IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= 0')
+                    ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 0) (Syntax: '0')
          Initializer: 
-            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null) (Syntax: '= 0')
-              ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 0) (Syntax: '0')
+            null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS0219: The variable 'i' is assigned but its value is never used

--- a/src/Compilers/CSharp/Test/Semantic/Semantics/DeconstructionTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/DeconstructionTests.cs
@@ -3903,16 +3903,20 @@ static void Main()
 ";
            string expectedOperationTree = @"
 IVariableDeclarationGroupOperation (1 declarations) (OperationKind.VariableDeclarationGroup, Type: null, IsInvalid) (Syntax: 'const (int  ... ) = (1, 2);')
-  ISingleVariableDeclarationOperation (Symbol: (System.Int32 x, System.Int32 y) ) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: '= (1, 2)')
+  IMultiVariableDeclarationOperation (1 declarations) (OperationKind.MultiVariableDeclaration, Type: null, IsInvalid) (Syntax: '(int x, int y) = (1, 2)')
+    Declarations:
+        ISingleVariableDeclarationOperation (Symbol: (System.Int32 x, System.Int32 y) ) (OperationKind.SingleVariableDeclaration, Type: null, IsInvalid) (Syntax: '= (1, 2)')
+          Initializer: 
+            IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= (1, 2)')
+              IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: (System.Int32 x, System.Int32 y), IsImplicit) (Syntax: '(1, 2)')
+                Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
+                Operand: 
+                  ITupleOperation (OperationKind.Tuple, Type: (System.Int32, System.Int32)) (Syntax: '(1, 2)')
+                    Elements(2):
+                        ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 1) (Syntax: '1')
+                        ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 2) (Syntax: '2')
    Initializer: 
-      IVariableInitializerOperation (OperationKind.VariableInitializer, Type: null, IsInvalid) (Syntax: '= (1, 2)')
-        IConversionOperation (Implicit, TryCast: False, Unchecked) (OperationKind.Conversion, Type: (System.Int32 x, System.Int32 y), IsImplicit) (Syntax: '(1, 2)')
-          Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-          Operand: 
-            ITupleOperation (OperationKind.Tuple, Type: (System.Int32, System.Int32)) (Syntax: '(1, 2)')
-              Elements(2):
-                  ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 1) (Syntax: '1')
-                  ILiteralOperation (OperationKind.Literal, Type: System.Int32, Constant: 2) (Syntax: '2')
+      null
 ";
            var expectedDiagnostics = new DiagnosticDescription[] {
                // CS1001: Identifier expected

--- a/src/Compilers/CSharp/Test/Semantic/Semantics/ObjectAndCollectionInitializerTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/ObjectAndCollectionInitializerTests.cs
--- a/src/Compilers/CSharp/Test/Semantic/Semantics/OperatorTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/OperatorTests.cs
--- a/src/Compilers/CSharp/Test/Symbol/Symbols/AnonymousTypesSemanticsTests.cs
+++ b/src/Compilers/CSharp/Test/Symbol/Symbols/AnonymousTypesSemanticsTests.cs
--- a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
+++ b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
@@ -5418,7 +5418,7 @@ public LazyUsingStatement(Lazy<IOperation> resources, Lazy<IOperation> body, Sem
    /// <summary>
    /// Represents a local variable declaration.
    /// </summary>
-    internal abstract partial class BaseVariableDeclaration : Operation, IVariableDeclarationOperation
+    internal abstract partial class BaseVariableDeclaration : Operation
    {
        protected BaseVariableDeclaration(OperationKind kind, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue, bool isImplicit) :
                    base(kind, semanticModel, syntax, type, constantValue, isImplicit)
@@ -5571,7 +5571,7 @@ internal abstract partial class BaseVariableDeclarationGroupOperation : Operatio
        {
        }

-        protected abstract ImmutableArray<IVariableDeclarationOperation> DeclarationsImpl { get; }
+        protected abstract ImmutableArray<IMultiVariableDeclarationOperation> DeclarationsImpl { get; }
        public override IEnumerable<IOperation> Children
        {
            get
@@ -5588,7 +5588,7 @@ public override IEnumerable<IOperation> Children
        /// <summary>
        /// Variables declared by the statement.
        /// </summary>
-        public ImmutableArray<IVariableDeclarationOperation> Declarations => Operation.SetParentOperation(DeclarationsImpl, this);
+        public ImmutableArray<IMultiVariableDeclarationOperation> Declarations => Operation.SetParentOperation(DeclarationsImpl, this);
        public override void Accept(OperationVisitor visitor)
        {
            visitor.VisitVariableDeclarationGroup(this);
@@ -5604,13 +5604,13 @@ public override void Accept(OperationVisitor visitor)
    /// </summary>
    internal sealed partial class VariableDeclarationGroupOperation : BaseVariableDeclarationGroupOperation, IVariableDeclarationGroupOperation
    {
-        public VariableDeclarationGroupOperation(ImmutableArray<IVariableDeclarationOperation> declarations, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue, bool isImplicit) :
+        public VariableDeclarationGroupOperation(ImmutableArray<IMultiVariableDeclarationOperation> declarations, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue, bool isImplicit) :
            base(semanticModel, syntax, type, constantValue, isImplicit)
        {
            DeclarationsImpl = declarations;
        }

-        protected override ImmutableArray<IVariableDeclarationOperation> DeclarationsImpl { get; }
+        protected override ImmutableArray<IMultiVariableDeclarationOperation> DeclarationsImpl { get; }
    }

    /// <summary>
@@ -5618,14 +5618,14 @@ internal sealed partial class VariableDeclarationGroupOperation : BaseVariableDe
    /// </summary>
    internal sealed partial class LazyVariableDeclarationGroupOperation : BaseVariableDeclarationGroupOperation, IVariableDeclarationGroupOperation
    {
-        private readonly Lazy<ImmutableArray<IVariableDeclarationOperation>> _lazyDeclarations;
+        private readonly Lazy<ImmutableArray<IMultiVariableDeclarationOperation>> _lazyDeclarations;

-        public LazyVariableDeclarationGroupOperation(Lazy<ImmutableArray<IVariableDeclarationOperation>> declarations, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue, bool isImplicit) : base(semanticModel, syntax, type, constantValue, isImplicit)
+        public LazyVariableDeclarationGroupOperation(Lazy<ImmutableArray<IMultiVariableDeclarationOperation>> declarations, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue, bool isImplicit) : base(semanticModel, syntax, type, constantValue, isImplicit)
        {
            _lazyDeclarations = declarations;
        }

-        protected override ImmutableArray<IVariableDeclarationOperation> DeclarationsImpl => _lazyDeclarations.Value;
+        protected override ImmutableArray<IMultiVariableDeclarationOperation> DeclarationsImpl => _lazyDeclarations.Value;
    }

    /// <summary>

--- a/src/Compilers/Core/Portable/Operations/IDeclarationExpressionOperation.cs
+++ b/src/Compilers/Core/Portable/Operations/IDeclarationExpressionOperation.cs
@@ -3,7 +3,7 @@
 namespace Microsoft.CodeAnalysis.Operations
 {
    /// <summary>
-    /// Represents a declaration expression operation. Unlike a regular variable declaration <see cref="IVariableDeclarationOperation"/>, this operation represents an "expression" declaring a variable.
+    /// Represents a declaration expression operation. Unlike a regular variable declaration <see cref="ISingleVariableDeclarationOperation"/> and <see cref="IMultiVariableDeclarationOperation"/>, this operation represents an "expression" declaring a variable.
    /// <para>
    /// Current usage:
    ///  (1) C# declaration expression. For example,

--- a/src/Compilers/Core/Portable/Operations/IMultiVariableDeclarationOperation.cs
+++ b/src/Compilers/Core/Portable/Operations/IMultiVariableDeclarationOperation.cs
@@ -5,25 +5,41 @@
 namespace Microsoft.CodeAnalysis.Operations
 {
    /// <summary>
-    /// Represents multiple declared variables in a single declarator.
+    /// Represents a declarator that declares multiple individual variables.
    /// </summary>
    /// <para>
    /// Current Usage:
-    ///   (1) VB Dim statement declaration groups
-    ///   (2) VB Using statement variable declarations
+    ///   (1) C# VariableDeclaration
+    ///   (2) C# fixed declarations
+    ///   (3) C# using declarations
+    ///   (4) VB Dim statement declaration groups
+    ///   (5) VB Using statement variable declarations
    /// </para>
    /// <remarks>
    /// The initializer of this node is applied to all individual declarations in <see cref="Declarations"/>. There cannot
    /// be initializers in both locations except in invalid code scenarios.
+    /// In C#, this node will never have an initializer.
    ///
    /// This interface is reserved for implementation by its associated APIs. We reserve the right to
    /// change it in the future.
    /// </remarks>
-    public interface IMultiVariableDeclarationOperation : IVariableDeclarationOperation
+    public interface IMultiVariableDeclarationOperation : IOperation
    {
        /// <summary>
        /// Individual variable declarations declared by this multiple declaration.
        /// </summary>
+        /// <remarks>
+        /// All <see cref="IVariableDeclarationGroupOperation"/> will have at least 1 <code>IMultiVariableDeclarationOpertion</code>,
+        /// even if the declaration group only declares 1 variable.
+        /// </remarks>
        ImmutableArray<ISingleVariableDeclarationOperation> Declarations { get; }
+
+        /// <summary>
+        /// Optional initializer of the variable.
+        /// </summary>
+        /// <remarks>
+        /// In C#, this will always be null.
+        /// </remarks>
+        IVariableInitializerOperation Initializer { get; }
    }
 }
--- a/src/Compilers/Core/Portable/Operations/ISingleVariableDeclarationOperation.cs
+++ b/src/Compilers/Core/Portable/Operations/ISingleVariableDeclarationOperation.cs
@@ -18,11 +18,21 @@ namespace Microsoft.CodeAnalysis.Operations
    /// This interface is reserved for implementation by its associated APIs. We reserve the right to
    /// change it in the future.
    /// </remarks>
-    public interface ISingleVariableDeclarationOperation : IVariableDeclarationOperation
+    public interface ISingleVariableDeclarationOperation : IOperation
    {
        /// <summary>
        /// Symbol declared by this variable declaration
        /// </summary>
        ILocalSymbol Symbol { get; }
+
+        /// <summary>
+        /// Optional initializer of the variable.
+        /// </summary>
+        /// <remarks>
+        /// If this variable is in an <see cref="IMultiVariableDeclarationOperation"/>, the initializer may be located
+        /// in the parent operation. Call <see cref="OperationExtensions.GetVariableInitializer(ISingleVariableDeclarationOperation)"/>
+        /// to check in all locations. It is only possible to have initializers in both locations in VB invalid code scenarios.
+        /// </remarks>
+        IVariableInitializerOperation Initializer { get; }
    }
 }
--- a/src/Compilers/Core/Portable/Operations/IVariableDeclarationGroupOperation.cs
+++ b/src/Compilers/Core/Portable/Operations/IVariableDeclarationGroupOperation.cs
@@ -5,7 +5,7 @@
 namespace Microsoft.CodeAnalysis.Operations
 {
    /// <summary>
-    /// Represents a local variable declaration statement.
+    /// Represents a variable declaration statement.
    /// </summary>
    /// <para>
    /// Current Usage:
@@ -22,8 +22,11 @@ namespace Microsoft.CodeAnalysis.Operations
    public interface IVariableDeclarationGroupOperation : IOperation
    {
        /// <summary>
-        /// Variables declared by the statement.
+        /// Variable declaration in the statement.
        /// </summary>
-        ImmutableArray<IVariableDeclarationOperation> Declarations { get; }
+        /// <remarks>
+        /// In C#, this will always be a single declaration, with all variables in <see cref="IMultiVariableDeclarationOperation.Declarations"/>.
+        /// </remarks>
+        ImmutableArray<IMultiVariableDeclarationOperation> Declarations { get; }
    }
 }
--- a/src/Compilers/Core/Portable/Operations/IVariableDeclarationOperation.cs
+++ b/src/Compilers/Core/Portable/Operations/IVariableDeclarationOperation.cs
--- a/src/Compilers/Core/Portable/Operations/OperationExtensions.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationExtensions.cs
--- a/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
+++ b/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -1251,8 +1251,8 @@ Namespace Microsoft.CodeAnalysis.Operations
        End Function

        Private Function CreateBoundDimStatementOperation(boundDimStatement As BoundDimStatement) As IVariableDeclarationGroupOperation
-            Dim declarations As Lazy(Of ImmutableArray(Of IVariableDeclarationOperation)) =
-                New Lazy(Of ImmutableArray(Of IVariableDeclarationOperation))(Function() GetVariableDeclarationStatementVariables(boundDimStatement.LocalDeclarations))
+            Dim declarations As Lazy(Of ImmutableArray(Of IMultiVariableDeclarationOperation)) =
+                New Lazy(Of ImmutableArray(Of IMultiVariableDeclarationOperation))(Function() GetVariableDeclarationStatementVariables(boundDimStatement.LocalDeclarations))
            Dim syntax As SyntaxNode = boundDimStatement.Syntax
            Dim type As ITypeSymbol = Nothing
            Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()

--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory_Methods.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory_Methods.vb
--- a/src/Test/Utilities/Portable/Diagnostics/CouldHaveMoreSpecificTypeAnalyzer.cs
+++ b/src/Test/Utilities/Portable/Diagnostics/CouldHaveMoreSpecificTypeAnalyzer.cs
--- a/src/Test/Utilities/Portable/Diagnostics/LocalCouldBeConstAnalyzer.cs
+++ b/src/Test/Utilities/Portable/Diagnostics/LocalCouldBeConstAnalyzer.cs
--- a/src/Test/Utilities/Portable/Diagnostics/OperationTestAnalyzer.cs
+++ b/src/Test/Utilities/Portable/Diagnostics/OperationTestAnalyzer.cs