Merge pull request #20962 from mavasani/ObjectCreations

Add IOperation support for variations of object creation expressions …

src/Compilers/CSharp/Portable/Binder/Binder_Expressions.cs

@@ -4469,6 +4469,7 @@ private bool IsConstructorAccessible(MethodSymbol constructor, ref HashSet<Diagn
 
                     result = new BoundDynamicObjectCreationExpression(
                         node,
+                        typeName,
                         argArray,
                         analyzedArguments.GetNames(),
                         analyzedArguments.RefKinds.ToImmutableOrNull(),

src/Compilers/CSharp/Portable/BoundTree/BoundNodes.xml

@@ -1289,6 +1289,7 @@
   <Node Name="BoundDynamicObjectCreationExpression" Base="BoundExpression">
     <!-- Non-null type is required for this node kind -->
     <Field Name="Type" Type="TypeSymbol" Override="true" Null="disallow"/>
+    <Field Name="Name" Type="string" Null="disallow"/>
     <Field Name="Arguments" Type="ImmutableArray&lt;BoundExpression&gt;"/>
     <Field Name="ArgumentNamesOpt" Type="ImmutableArray&lt;string&gt;" Null="allow"/>
     <Field Name="ArgumentRefKindsOpt" Type="ImmutableArray&lt;RefKind&gt;" Null="allow"/>

src/Compilers/CSharp/Portable/Generated/BoundNodes.xml.Generated.cs

@@ -4650,14 +4650,16 @@ public BoundConvertedTupleLiteral Update(TypeSymbol naturalTypeOpt, ImmutableArr
 
     internal sealed partial class BoundDynamicObjectCreationExpression : BoundExpression
     {
-        public BoundDynamicObjectCreationExpression(SyntaxNode syntax, ImmutableArray<BoundExpression> arguments, ImmutableArray<string> argumentNamesOpt, ImmutableArray<RefKind> argumentRefKindsOpt, BoundExpression initializerExpressionOpt, ImmutableArray<MethodSymbol> applicableMethods, TypeSymbol type, bool hasErrors = false)
+        public BoundDynamicObjectCreationExpression(SyntaxNode syntax, string name, ImmutableArray<BoundExpression> arguments, ImmutableArray<string> argumentNamesOpt, ImmutableArray<RefKind> argumentRefKindsOpt, BoundExpression initializerExpressionOpt, ImmutableArray<MethodSymbol> applicableMethods, TypeSymbol type, bool hasErrors = false)
             : base(BoundKind.DynamicObjectCreationExpression, syntax, type, hasErrors || arguments.HasErrors() || initializerExpressionOpt.HasErrors())
         {
 
+            Debug.Assert(name != null, "Field 'name' cannot be null (use Null=\"allow\" in BoundNodes.xml to remove this check)");
             Debug.Assert(!arguments.IsDefault, "Field 'arguments' cannot be null (use Null=\"allow\" in BoundNodes.xml to remove this check)");
             Debug.Assert(!applicableMethods.IsDefault, "Field 'applicableMethods' cannot be null (use Null=\"allow\" in BoundNodes.xml to remove this check)");
             Debug.Assert(type != null, "Field 'type' cannot be null (use Null=\"allow\" in BoundNodes.xml to remove this check)");
 
+            this.Name = name;
             this.Arguments = arguments;
             this.ArgumentNamesOpt = argumentNamesOpt;
             this.ArgumentRefKindsOpt = argumentRefKindsOpt;
@@ -4666,6 +4668,8 @@ public BoundDynamicObjectCreationExpression(SyntaxNode syntax, ImmutableArray<Bo
         }
 
 
+        public string Name { get; }
+
         public ImmutableArray<BoundExpression> Arguments { get; }
 
         public ImmutableArray<string> ArgumentNamesOpt { get; }
@@ -4681,11 +4685,11 @@ public override BoundNode Accept(BoundTreeVisitor visitor)
             return visitor.VisitDynamicObjectCreationExpression(this);
         }
 
-        public BoundDynamicObjectCreationExpression Update(ImmutableArray<BoundExpression> arguments, ImmutableArray<string> argumentNamesOpt, ImmutableArray<RefKind> argumentRefKindsOpt, BoundExpression initializerExpressionOpt, ImmutableArray<MethodSymbol> applicableMethods, TypeSymbol type)
+        public BoundDynamicObjectCreationExpression Update(string name, ImmutableArray<BoundExpression> arguments, ImmutableArray<string> argumentNamesOpt, ImmutableArray<RefKind> argumentRefKindsOpt, BoundExpression initializerExpressionOpt, ImmutableArray<MethodSymbol> applicableMethods, TypeSymbol type)
         {
-            if (arguments != this.Arguments || argumentNamesOpt != this.ArgumentNamesOpt || argumentRefKindsOpt != this.ArgumentRefKindsOpt || initializerExpressionOpt != this.InitializerExpressionOpt || applicableMethods != this.ApplicableMethods || type != this.Type)
+            if (name != this.Name || arguments != this.Arguments || argumentNamesOpt != this.ArgumentNamesOpt || argumentRefKindsOpt != this.ArgumentRefKindsOpt || initializerExpressionOpt != this.InitializerExpressionOpt || applicableMethods != this.ApplicableMethods || type != this.Type)
             {
-                var result = new BoundDynamicObjectCreationExpression(this.Syntax, arguments, argumentNamesOpt, argumentRefKindsOpt, initializerExpressionOpt, applicableMethods, type, this.HasErrors);
+                var result = new BoundDynamicObjectCreationExpression(this.Syntax, name, arguments, argumentNamesOpt, argumentRefKindsOpt, initializerExpressionOpt, applicableMethods, type, this.HasErrors);
                 result.WasCompilerGenerated = this.WasCompilerGenerated;
                 return result;
             }
@@ -9020,7 +9024,7 @@ public override BoundNode VisitDynamicObjectCreationExpression(BoundDynamicObjec
             ImmutableArray<BoundExpression> arguments = (ImmutableArray<BoundExpression>)this.VisitList(node.Arguments);
             BoundExpression initializerExpressionOpt = (BoundExpression)this.Visit(node.InitializerExpressionOpt);
             TypeSymbol type = this.VisitType(node.Type);
-            return node.Update(arguments, node.ArgumentNamesOpt, node.ArgumentRefKindsOpt, initializerExpressionOpt, node.ApplicableMethods, type);
+            return node.Update(node.Name, arguments, node.ArgumentNamesOpt, node.ArgumentRefKindsOpt, initializerExpressionOpt, node.ApplicableMethods, type);
         }
         public override BoundNode VisitNoPiaObjectCreationExpression(BoundNoPiaObjectCreationExpression node)
         {
@@ -10402,6 +10406,7 @@ public override TreeDumperNode VisitDynamicObjectCreationExpression(BoundDynamic
         {
             return new TreeDumperNode("dynamicObjectCreationExpression", null, new TreeDumperNode[]
             {
+                new TreeDumperNode("name", node.Name, null),
                 new TreeDumperNode("arguments", null, from x in node.Arguments select Visit(x, null)),
                 new TreeDumperNode("argumentNamesOpt", node.ArgumentNamesOpt, null),
                 new TreeDumperNode("argumentRefKindsOpt", node.ArgumentRefKindsOpt, null),

src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs

@@ -59,6 +59,8 @@ private IOperation CreateInternal(BoundNode boundNode)
                     return CreateBoundLiteralOperation((BoundLiteral)boundNode);
                 case BoundKind.ObjectCreationExpression:
                     return CreateBoundObjectCreationExpressionOperation((BoundObjectCreationExpression)boundNode);
+                case BoundKind.DynamicObjectCreationExpression:
+                    return CreateBoundDynamicObjectCreationExpressionOperation((BoundDynamicObjectCreationExpression)boundNode);
                 case BoundKind.ObjectInitializerExpression:
                     return CreateBoundObjectInitializerExpressionOperation((BoundObjectInitializerExpression)boundNode);
                 case BoundKind.CollectionInitializerExpression:
@@ -425,6 +427,20 @@ private IObjectCreationExpression CreateBoundObjectCreationExpressionOperation(B
             return new LazyObjectCreationExpression(constructor, initializer, argumentsInEvaluationOrder, syntax, type, constantValue);
         }
 
+        private IDynamicObjectCreationExpression CreateBoundDynamicObjectCreationExpressionOperation(BoundDynamicObjectCreationExpression boundDynamicObjectCreationExpression)
+        {
+            string name = boundDynamicObjectCreationExpression.Name;
+            ImmutableArray<ISymbol> applicableSymbols = StaticCast<ISymbol>.From(boundDynamicObjectCreationExpression.ApplicableMethods);
+            Lazy<ImmutableArray<IOperation>> arguments = new Lazy<ImmutableArray<IOperation>>(() => boundDynamicObjectCreationExpression.Arguments.SelectAsArray(n => Create(n)));
+            ImmutableArray<string> argumentNames = boundDynamicObjectCreationExpression.ArgumentNamesOpt.NullToEmpty();
+            ImmutableArray<RefKind> argumentRefKinds = boundDynamicObjectCreationExpression.ArgumentRefKindsOpt.NullToEmpty();
+            Lazy<IObjectOrCollectionInitializerExpression> initializer = new Lazy<IObjectOrCollectionInitializerExpression>(() => (IObjectOrCollectionInitializerExpression)Create(boundDynamicObjectCreationExpression.InitializerExpressionOpt));
+            SyntaxNode syntax = boundDynamicObjectCreationExpression.Syntax;
+            ITypeSymbol type = boundDynamicObjectCreationExpression.Type;
+            Optional<object> constantValue = ConvertToOptional(boundDynamicObjectCreationExpression.ConstantValue);
+            return new LazyDynamicObjectCreationExpression(name, applicableSymbols, arguments, argumentNames, argumentRefKinds, initializer, syntax, type, constantValue);
+        }
+
         private IObjectOrCollectionInitializerExpression CreateBoundObjectInitializerExpressionOperation(BoundObjectInitializerExpression boundObjectInitializerExpression)
         {
             Lazy<ImmutableArray<IOperation>> initializers = new Lazy<ImmutableArray<IOperation>>(() => BoundObjectCreationExpression.GetChildInitializers(boundObjectInitializerExpression).SelectAsArray(n => Create(n)));
@@ -733,10 +749,11 @@ private IInvalidExpression CreateBoundBadExpressionOperation(BoundBadExpression
 
         private ITypeParameterObjectCreationExpression CreateBoundNewTOperation(BoundNewT boundNewT)
         {
+            Lazy<IObjectOrCollectionInitializerExpression> initializer = new Lazy<IObjectOrCollectionInitializerExpression>(() => (IObjectOrCollectionInitializerExpression)Create(boundNewT.InitializerExpressionOpt));
             SyntaxNode syntax = boundNewT.Syntax;
             ITypeSymbol type = boundNewT.Type;
             Optional<object> constantValue = ConvertToOptional(boundNewT.ConstantValue);
-            return new TypeParameterObjectCreationExpression(syntax, type, constantValue);
+            return new LazyTypeParameterObjectCreationExpression(initializer, syntax, type, constantValue);
         }
 
         private IUnaryOperatorExpression CreateBoundUnaryOperatorOperation(BoundUnaryOperator boundUnaryOperator)

src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs

-using System;
+using System;
 using System.Linq;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.CSharp.Test.Utilities;
@@ -1904,6 +1904,7 @@ class C2 : C1
     Variables: Local_1: C1 c1
     Initializer: IConversionExpression (ConversionKind.Cast, Implicit) (OperationKind.ConversionExpression, Type: C1) (Syntax: 'new T()')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T) (Syntax: 'new T()')
+        null
 ";
             var expectedDiagnostics = DiagnosticDescription.None;
 
@@ -1935,6 +1936,7 @@ class C2 : C1
     Variables: Local_1: C1 c1
     Initializer: IConversionExpression (ConversionKind.Invalid, Implicit) (OperationKind.ConversionExpression, Type: C1, IsInvalid) (Syntax: 'new T()')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T, IsInvalid) (Syntax: 'new T()')
+        null
 ";
             var expectedDiagnostics = new DiagnosticDescription[] {
                 // CS0029: Cannot implicitly convert type 'T' to 'C1'
@@ -1969,6 +1971,7 @@ static void M1<T>()
     Variables: Local_1: I1 i1
     Initializer: IConversionExpression (ConversionKind.Cast, Implicit) (OperationKind.ConversionExpression, Type: I1) (Syntax: 'new T()')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T) (Syntax: 'new T()')
+        null
 ";
             var expectedDiagnostics = DiagnosticDescription.None;
 
@@ -1999,6 +2002,7 @@ static void M1<T>()
     Variables: Local_1: I1 i1
     Initializer: IConversionExpression (ConversionKind.Cast, Implicit) (OperationKind.ConversionExpression, Type: I1, IsInvalid) (Syntax: 'new T()')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T, IsInvalid) (Syntax: 'new T()')
+        null
 ";
             var expectedDiagnostics = new DiagnosticDescription[] {
                 // CS0266: Cannot implicitly convert type 'T' to 'I1'. An explicit conversion exists (are you missing a cast?)
@@ -2034,6 +2038,7 @@ class C1
     Variables: Local_1: U u
     Initializer: IConversionExpression (ConversionKind.Cast, Implicit) (OperationKind.ConversionExpression, Type: U) (Syntax: 'new T()')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T) (Syntax: 'new T()')
+        null
 ";
             var expectedDiagnostics = DiagnosticDescription.None;
 
@@ -2065,6 +2070,7 @@ class C1
     Variables: Local_1: U u
     Initializer: IConversionExpression (ConversionKind.Invalid, Implicit) (OperationKind.ConversionExpression, Type: U, IsInvalid) (Syntax: 'new T()')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T, IsInvalid) (Syntax: 'new T()')
+        null
 ";
             var expectedDiagnostics = new DiagnosticDescription[] {
                 // CS0029: Cannot implicitly convert type 'T' to 'U'

src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IDynamicObjectCreationExpression.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Test.Utilities;
+using Roslyn.Test.Utilities;
+using Xunit;
+
+namespace Microsoft.CodeAnalysis.CSharp.UnitTests
+{
+    public partial class IOperationTests : SemanticModelTestBase
+    {
+        [Fact]
+        public void DynamicObjectCreation_DynamicArgument()
+        {
+            string source = @"
+class C
+{
+    public C(int i)
+    {
+    }
+
+    void M(dynamic d)
+    {
+        var x = /*<bind>*/new C(d)/*</bind>*/;
+    }
+}
+";
+            string expectedOperationTree = @"
+IDynamicObjectCreationExpression (Name: C) (OperationKind.TypeParameterObjectCreationExpression, Type: C) (Syntax: 'new C(d)')
+  ApplicableSymbols(1):
+    Symbol: C..ctor(System.Int32 i)
+  Arguments(1):
+      IParameterReferenceExpression: d (OperationKind.ParameterReferenceExpression, Type: dynamic) (Syntax: 'd')
+  ArgumentNames(0)
+  ArgumentRefKinds(0)
+  Initializer: null
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<ObjectCreationExpressionSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [Fact]
+        public void DynamicObjectCreation_MultipleApplicableSymbols()
+        {
+            string source = @"
+class C
+{
+    public C(int i)
+    {
+    }
+
+    public C(long i)
+    {
+    }
+
+    void M(dynamic d)
+    {
+        var x = /*<bind>*/new C(d)/*</bind>*/;
+    }
+}
+";
+            string expectedOperationTree = @"
+IDynamicObjectCreationExpression (Name: C) (OperationKind.TypeParameterObjectCreationExpression, Type: C) (Syntax: 'new C(d)')
+  ApplicableSymbols(2):
+    Symbol: C..ctor(System.Int32 i)
+    Symbol: C..ctor(System.Int64 i)
+  Arguments(1):
+      IParameterReferenceExpression: d (OperationKind.ParameterReferenceExpression, Type: dynamic) (Syntax: 'd')
+  ArgumentNames(0)
+  ArgumentRefKinds(0)
+  Initializer: null
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<ObjectCreationExpressionSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [Fact]
+        public void DynamicObjectCreation_MultipleArgumentsAndApplicableSymbols()
+        {
+            string source = @"
+class C
+{
+    public C(int i, char c)
+    {
+    }
+
+    public C(long i, char c)
+    {
+    }
+
+    void M(dynamic d)
+    {
+        char c = 'c';
+        var x = /*<bind>*/new C(d, c)/*</bind>*/;
+    }
+}
+";
+            string expectedOperationTree = @"
+IDynamicObjectCreationExpression (Name: C) (OperationKind.TypeParameterObjectCreationExpression, Type: C) (Syntax: 'new C(d, c)')
+  ApplicableSymbols(2):
+    Symbol: C..ctor(System.Int32 i, System.Char c)
+    Symbol: C..ctor(System.Int64 i, System.Char c)
+  Arguments(2):
+      IParameterReferenceExpression: d (OperationKind.ParameterReferenceExpression, Type: dynamic) (Syntax: 'd')
+      ILocalReferenceExpression: c (OperationKind.LocalReferenceExpression, Type: System.Char) (Syntax: 'c')
+  ArgumentNames(0)
+  ArgumentRefKinds(0)
+  Initializer: null
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<ObjectCreationExpressionSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [Fact]
+        public void DynamicObjectCreation_ArgumentNames()
+        {
+            string source = @"
+class C
+{
+    public C(int i, char c)
+    {
+    }
+
+    public C(long i, char c)
+    {
+    }
+
+    void M(dynamic d, dynamic e)
+    {
+        var x = /*<bind>*/new C(i: d, c: e)/*</bind>*/;
+    }
+}
+";
+            string expectedOperationTree = @"
+IDynamicObjectCreationExpression (Name: C) (OperationKind.TypeParameterObjectCreationExpression, Type: C) (Syntax: 'new C(i: d, c: e)')
+  ApplicableSymbols(2):
+    Symbol: C..ctor(System.Int32 i, System.Char c)
+    Symbol: C..ctor(System.Int64 i, System.Char c)
+  Arguments(2):
+      IParameterReferenceExpression: d (OperationKind.ParameterReferenceExpression, Type: dynamic) (Syntax: 'd')
+      IParameterReferenceExpression: e (OperationKind.ParameterReferenceExpression, Type: dynamic) (Syntax: 'e')
+  ArgumentNames(2):
+    ""i""
+    ""c""
+  ArgumentRefKinds(0)
+  Initializer: null
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<ObjectCreationExpressionSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [Fact]
+        public void DynamicObjectCreation_ArgumentRefKinds()
+        {
+            string source = @"
+class C
+{
+    public C(ref object i, out int j, char c)
+    {
+        j = 0;
+    }
+
+    void M(object d, dynamic e)
+    {
+        int k;
+        var x = /*<bind>*/new C(ref d, out k, e)/*</bind>*/;
+    }
+}
+";
+            string expectedOperationTree = @"
+IDynamicObjectCreationExpression (Name: C) (OperationKind.TypeParameterObjectCreationExpression, Type: C) (Syntax: 'new C(ref d, out k, e)')
+  ApplicableSymbols(1):
+    Symbol: C..ctor(ref System.Object i, out System.Int32 j, System.Char c)
+  Arguments(3):
+      IParameterReferenceExpression: d (OperationKind.ParameterReferenceExpression, Type: System.Object) (Syntax: 'd')
+      ILocalReferenceExpression: k (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'k')
+      IParameterReferenceExpression: e (OperationKind.ParameterReferenceExpression, Type: dynamic) (Syntax: 'e')
+  ArgumentNames(0)
+  ArgumentRefKinds(3):
+    Ref
+    Out
+    None
+  Initializer: null
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<ObjectCreationExpressionSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [Fact]
+        public void DynamicObjectCreation_Initializer()
+        {
+            string source = @"
+class C
+{
+    public int X;
+
+    public C(char c)
+    {
+    }
+
+    void M(dynamic d)
+    {
+        var x = /*<bind>*/new C(d) { X = 0 }/*</bind>*/;
+    }
+}
+";
+            string expectedOperationTree = @"
+IDynamicObjectCreationExpression (Name: C) (OperationKind.TypeParameterObjectCreationExpression, Type: C) (Syntax: 'new C(d) { X = 0 }')
+  ApplicableSymbols(1):
+    Symbol: C..ctor(System.Char c)
+  Arguments(1):
+      IParameterReferenceExpression: d (OperationKind.ParameterReferenceExpression, Type: dynamic) (Syntax: 'd')
+  ArgumentNames(0)
+  ArgumentRefKinds(0)
+  Initializer: IObjectOrCollectionInitializerExpression (OperationKind.ObjectOrCollectionInitializerExpression, Type: C) (Syntax: '{ X = 0 }')
+      Initializers(1):
+          ISimpleAssignmentExpression (OperationKind.SimpleAssignmentExpression, Type: System.Int32) (Syntax: 'X = 0')
+            Left: IFieldReferenceExpression: System.Int32 C.X (OperationKind.FieldReferenceExpression, Type: System.Int32) (Syntax: 'X')
+                Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C) (Syntax: 'X')
+            Right: ILiteralExpression (Text: 0) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 0) (Syntax: '0')
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<ObjectCreationExpressionSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [Fact]
+        public void DynamicObjectCreation_AllFields()
+        {
+            string source = @"
+class C
+{
+    public int X;
+
+    public C(ref int i, char c)
+    {
+    }
+
+    public C(ref int i, long c)
+    {
+    }
+
+    void M(dynamic d)
+    {
+        int i = 0;
+        var x = /*<bind>*/new C(ref i, c: d) { X = 0 }/*</bind>*/;
+    }
+}
+";
+            string expectedOperationTree = @"
+IDynamicObjectCreationExpression (Name: C) (OperationKind.TypeParameterObjectCreationExpression, Type: C) (Syntax: 'new C(ref i ... ) { X = 0 }')
+  ApplicableSymbols(2):
+    Symbol: C..ctor(ref System.Int32 i, System.Char c)
+    Symbol: C..ctor(ref System.Int32 i, System.Int64 c)
+  Arguments(2):
+      ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
+      IParameterReferenceExpression: d (OperationKind.ParameterReferenceExpression, Type: dynamic) (Syntax: 'd')
+  ArgumentNames(2):
+    ""null""
+    ""c""
+  ArgumentRefKinds(2):
+    Ref
+    None
+  Initializer: IObjectOrCollectionInitializerExpression (OperationKind.ObjectOrCollectionInitializerExpression, Type: C) (Syntax: '{ X = 0 }')
+      Initializers(1):
+          ISimpleAssignmentExpression (OperationKind.SimpleAssignmentExpression, Type: System.Int32) (Syntax: 'X = 0')
+            Left: IFieldReferenceExpression: System.Int32 C.X (OperationKind.FieldReferenceExpression, Type: System.Int32) (Syntax: 'X')
+                Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C) (Syntax: 'X')
+            Right: ILiteralExpression (Text: 0) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 0) (Syntax: '0')
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<ObjectCreationExpressionSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [Fact]
+        public void DynamicObjectCreation_ErrorBadDynamicMethodArgLambda()
+        {
+            string source = @"
+using System;
+
+class C
+{
+    static void Main()
+    {
+        dynamic y = null;
+        /*<bind>*/new C(delegate { }, y)/*</bind>*/;
+    }
+
+    public C(Action a, Action y)
+    {
+    }
+}
+";
+            string expectedOperationTree = @"
+IDynamicObjectCreationExpression (Name: C) (OperationKind.TypeParameterObjectCreationExpression, Type: C, IsInvalid) (Syntax: 'new C(delegate { }, y)')
+  ApplicableSymbols(1):
+    Symbol: C..ctor(System.Action a, System.Action y)
+  Arguments(2):
+      ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'delegate { }')
+        IBlockStatement (1 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '{ }')
+          IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: '{ }')
+          null
+      ILocalReferenceExpression: y (OperationKind.LocalReferenceExpression, Type: dynamic) (Syntax: 'y')
+  ArgumentNames(0)
+  ArgumentRefKinds(0)
+  Initializer: null
+";
+            var expectedDiagnostics = new DiagnosticDescription[] {
+                // CS1977: Cannot use a lambda expression as an argument to a dynamically dispatched operation without first casting it to a delegate or expression tree type.
+                //         /*<bind>*/new C(delegate { }, y)/*</bind>*/;
+                Diagnostic(ErrorCode.ERR_BadDynamicMethodArgLambda, "delegate { }").WithLocation(9, 25)
+            };
+
+            VerifyOperationTreeAndDiagnosticsForTest<ObjectCreationExpressionSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [Fact]
+        public void DynamicObjectCreation_OVerloadResolutionFailure()
+        {
+            string source = @"
+class C
+{
+    public C()
+    {
+    }
+
+    public C(int i, int j)
+    {
+    }
+
+    void M(dynamic d)
+    {
+        var x = /*<bind>*/new C(d)/*</bind>*/;
+    }
+}
+";
+            string expectedOperationTree = @"
+IInvalidExpression (OperationKind.InvalidExpression, Type: C, IsInvalid) (Syntax: 'new C(d)')
+  Children(1):
+      IParameterReferenceExpression: d (OperationKind.ParameterReferenceExpression, Type: dynamic) (Syntax: 'd')
+";
+            var expectedDiagnostics = new DiagnosticDescription[] {
+                // CS7036: There is no argument given that corresponds to the required formal parameter 'j' of 'C.C(int, int)'
+                //         var x = /*<bind>*/new C(d)/*</bind>*/;
+                Diagnostic(ErrorCode.ERR_NoCorrespondingArgument, "C").WithArguments("j", "C.C(int, int)").WithLocation(14, 31)
+            };
+
+            VerifyOperationTreeAndDiagnosticsForTest<ObjectCreationExpressionSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+    }
+}

src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IParameterReferenceExpression.cs

@@ -598,9 +598,15 @@ public void M(dynamic x)
 }
 ";
     string expectedOperationTree = @"
-IOperation:  (OperationKind.None) (Syntax: 'new Class(x)')
-  Children(1):
+IDynamicObjectCreationExpression (Name: Class) (OperationKind.TypeParameterObjectCreationExpression, Type: Class) (Syntax: 'new Class(x)')
+  ApplicableSymbols(2):
+    Symbol: Class..ctor(Class x)
+    Symbol: Class..ctor(System.String x)
+  Arguments(1):
       IParameterReferenceExpression: x (OperationKind.ParameterReferenceExpression, Type: dynamic) (Syntax: 'x')
+  ArgumentNames(0)
+  ArgumentRefKinds(0)
+  Initializer: null
 ";
     var expectedDiagnostics = DiagnosticDescription.None;
 

src/Compilers/CSharp/Test/Semantic/Semantics/ObjectAndCollectionInitializerTests.cs

@@ -113,11 +113,18 @@ public static void Foo()
     }
 }
 ";
-
-            // Expected operation tree should expose the object initializer.
-            // See https://github.com/dotnet/roslyn/issues/20491.
-string expectedOperationTree = @"
+            string expectedOperationTree = @"
 ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T) (Syntax: 'new T() { x = 0, y = 0 }')
+  IObjectOrCollectionInitializerExpression (OperationKind.ObjectOrCollectionInitializerExpression, Type: T) (Syntax: '{ x = 0, y = 0 }')
+    Initializers(2):
+        ISimpleAssignmentExpression (OperationKind.SimpleAssignmentExpression, Type: System.Int32) (Syntax: 'x = 0')
+          Left: IFieldReferenceExpression: System.Int32 Base.x (OperationKind.FieldReferenceExpression, Type: System.Int32) (Syntax: 'x')
+              Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: Base) (Syntax: 'x')
+          Right: ILiteralExpression (Text: 0) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 0) (Syntax: '0')
+        ISimpleAssignmentExpression (OperationKind.SimpleAssignmentExpression, Type: System.Int32) (Syntax: 'y = 0')
+          Left: IPropertyReferenceExpression: System.Int32 Base.y { get; set; } (OperationKind.PropertyReferenceExpression, Type: System.Int32) (Syntax: 'y')
+              Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: Base) (Syntax: 'y')
+          Right: ILiteralExpression (Text: 0) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 0) (Syntax: '0')
 ";
             var expectedDiagnostics = DiagnosticDescription.None;
 

src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs

@@ -4867,13 +4867,12 @@ internal abstract partial class TypeOperationExpression : Operation, ITypeOperat
         public ITypeSymbol TypeOperand { get; }
     }
 
-    /// <remarks>
-    /// This interface is reserved for implementation by its associated APIs. We reserve the right to
-    /// change it in the future.
-    /// </remarks>
-    internal sealed partial class TypeParameterObjectCreationExpression : Operation, ITypeParameterObjectCreationExpression
+    /// <summary>
+    /// Represents a type parameter object creation expression, i.e. new T(), where T is a type parameter with new constraint.
+    /// </summary>
+    internal abstract partial class BaseTypeParameterObjectCreationExpression : Operation, ITypeParameterObjectCreationExpression
     {
-        public TypeParameterObjectCreationExpression(SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+        public BaseTypeParameterObjectCreationExpression(SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
             base(OperationKind.TypeParameterObjectCreationExpression, syntax, type, constantValue)
         {
         }
@@ -4881,9 +4880,13 @@ public override IEnumerable<IOperation> Children
         {
             get
             {
-                yield break;
+                yield return Initializer;
             }
         }
+        /// <summary>
+        /// Object or collection initializer, if any.
+        /// </summary>
+        public abstract IObjectOrCollectionInitializerExpression Initializer { get; }
         public override void Accept(OperationVisitor visitor)
         {
             visitor.VisitTypeParameterObjectCreationExpression(this);
@@ -4894,6 +4897,137 @@ public override void Accept(OperationVisitor visitor)
         }
     }
 
+    /// <summary>
+    /// Represents a type parameter object creation expression, i.e. new T(), where T is a type parameter with new constraint.
+    /// </summary>
+    internal sealed partial class TypeParameterObjectCreationExpression : BaseTypeParameterObjectCreationExpression, ITypeParameterObjectCreationExpression
+    {
+        public TypeParameterObjectCreationExpression(IObjectOrCollectionInitializerExpression initializer, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+            base(syntax, type, constantValue)
+        {
+            Initializer = initializer;
+        }
+        /// <summary>
+        /// Object or collection initializer, if any.
+        /// </summary>
+        public override IObjectOrCollectionInitializerExpression Initializer { get; }
+    }
+
+    /// <summary>
+    /// Represents a type parameter object creation expression, i.e. new T(), where T is a type parameter with new constraint.
+    /// </summary>
+    internal sealed partial class LazyTypeParameterObjectCreationExpression : BaseTypeParameterObjectCreationExpression, ITypeParameterObjectCreationExpression
+    {
+        private readonly Lazy<IObjectOrCollectionInitializerExpression> _lazyInitializer;
+        public LazyTypeParameterObjectCreationExpression(Lazy<IObjectOrCollectionInitializerExpression> initializer, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+            base(syntax, type, constantValue)
+        {
+            _lazyInitializer = initializer ?? throw new System.ArgumentNullException(nameof(initializer));
+        }
+        /// <summary>
+        /// Object or collection initializer, if any.
+        /// </summary>
+        public override IObjectOrCollectionInitializerExpression Initializer => _lazyInitializer.Value;
+    }
+
+    /// <remarks>
+    /// Represents a dynamically bound new/New expression.
+    /// </remarks>
+    internal abstract partial class BaseDynamicObjectCreationExpression : Operation, IHasDynamicArgumentsExpression, IDynamicObjectCreationExpression
+    {
+        public BaseDynamicObjectCreationExpression(string name, ImmutableArray<ISymbol> applicableSymbols, ImmutableArray<string> argumentNames, ImmutableArray<RefKind> argumentRefKinds, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+            base(OperationKind.TypeParameterObjectCreationExpression, syntax, type, constantValue)
+        {
+            Name = name;
+            ApplicableSymbols = applicableSymbols;
+            ArgumentNames = argumentNames;
+            ArgumentRefKinds = argumentRefKinds;
+        }
+        public override IEnumerable<IOperation> Children
+        {
+            get
+            {
+                yield return Initializer;
+            }
+        }
+        /// <summary>
+        /// Name of the dynamically invoked member.
+        /// </summary>
+        public string Name { get; }
+        /// <summary>
+        /// List of applicable symbols that are dynamically bound to the <see cref="Name"/>.
+        /// </summary>
+        public ImmutableArray<ISymbol> ApplicableSymbols { get; }
+        /// <summary>
+        /// Dynamically bound arguments, excluding the instance argument.
+        /// </summary>
+        public abstract ImmutableArray<IOperation> Arguments { get; }
+        /// <summary>
+        /// Optional argument names for named arguments.
+        /// </summary>
+        public ImmutableArray<string> ArgumentNames { get; }
+        /// <summary>
+        /// Optional argument ref kinds.
+        /// </summary>
+        public ImmutableArray<RefKind> ArgumentRefKinds { get; }
+        /// <summary>
+        /// Object or collection initializer, if any.
+        /// </summary>
+        public abstract IObjectOrCollectionInitializerExpression Initializer { get; }
+        public override void Accept(OperationVisitor visitor)
+        {
+            visitor.VisitDynamicObjectCreationExpression(this);
+        }
+        public override TResult Accept<TArgument, TResult>(OperationVisitor<TArgument, TResult> visitor, TArgument argument)
+        {
+            return visitor.VisitDynamicObjectCreationExpression(this, argument);
+        }
+    }
+
+    /// <remarks>
+    /// Represents a dynamically bound new/New expression.
+    /// </remarks>
+    internal sealed partial class DynamicObjectCreationExpression : BaseDynamicObjectCreationExpression, IHasDynamicArgumentsExpression, IDynamicObjectCreationExpression
+    {
+        public DynamicObjectCreationExpression(string name, ImmutableArray<ISymbol> applicableSymbols, ImmutableArray<IOperation> arguments, ImmutableArray<string> argumentNames, ImmutableArray<RefKind> argumentRefKinds, IObjectOrCollectionInitializerExpression initializer, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+            base(name, applicableSymbols, argumentNames, argumentRefKinds, syntax, type, constantValue)
+        {
+            Arguments = arguments;
+            Initializer = initializer;
+        }
+        /// <summary>
+        /// Dynamically bound arguments, excluding the instance argument.
+        /// </summary>
+        public override ImmutableArray<IOperation> Arguments { get; }
+        /// <summary>
+        /// Object or collection initializer, if any.
+        /// </summary>
+        public override IObjectOrCollectionInitializerExpression Initializer { get; }
+    }
+
+    /// <remarks>
+    /// Represents a dynamically bound new/New expression.
+    /// </remarks>
+    internal sealed partial class LazyDynamicObjectCreationExpression : BaseDynamicObjectCreationExpression, IHasDynamicArgumentsExpression, IDynamicObjectCreationExpression
+    {
+        private readonly Lazy<IObjectOrCollectionInitializerExpression> _lazyInitializer;
+        private readonly Lazy<ImmutableArray<IOperation>> _lazyArguments;
+        public LazyDynamicObjectCreationExpression(string name, ImmutableArray<ISymbol> applicableSymbols, Lazy<ImmutableArray<IOperation>> arguments, ImmutableArray<string> argumentNames, ImmutableArray<RefKind> argumentRefKinds, Lazy<IObjectOrCollectionInitializerExpression> initializer, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+            base(name, applicableSymbols, argumentNames, argumentRefKinds, syntax, type, constantValue)
+        {
+            _lazyArguments = arguments ?? throw new System.ArgumentNullException(nameof(arguments));
+            _lazyInitializer = initializer ?? throw new System.ArgumentNullException(nameof(initializer));
+        }
+        /// <summary>
+        /// Dynamically bound arguments, excluding the instance argument.
+        /// </summary>
+        public override ImmutableArray<IOperation> Arguments => _lazyArguments.Value;
+        /// <summary>
+        /// Object or collection initializer, if any.
+        /// </summary>
+        public override IObjectOrCollectionInitializerExpression Initializer => _lazyInitializer.Value;
+    }
+
     /// <summary>
     /// Represents an operation with one operand.
     /// </summary>

src/Compilers/Core/Portable/Operations/IDynamicObjectCreationExpression.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+namespace Microsoft.CodeAnalysis.Semantics
+{
+    /// <summary>
+    /// Represents a dynamically bound new/New expression.
+    /// </summary>
+    /// <remarks>
+    /// This interface is reserved for implementation by its associated APIs. We reserve the right to
+    /// change it in the future.
+    /// </remarks>
+    public interface IDynamicObjectCreationExpression : IHasDynamicArgumentsExpression
+    {
+        /// <summary>
+        /// Object or collection initializer, if any.
+        /// </summary>
+        IObjectOrCollectionInitializerExpression Initializer { get; }
+    }
+}

src/Compilers/Core/Portable/Operations/IHasDynamicArgumentsExpression.cs

+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Collections.Immutable;
+
+namespace Microsoft.CodeAnalysis.Semantics
+{
+    /// <remarks>
+    /// This interface is reserved for implementation by its associated APIs. We reserve the right to
+    /// change it in the future.
+    /// </remarks>
+    public interface IHasDynamicArgumentsExpression : IOperation
+    {
+        /// <summary>
+        /// Name of the dynamically invoked member.
+        /// </summary>
+        string Name { get; }
+
+        /// <summary>
+        /// List of applicable symbols that are dynamically bound to the <see cref="Name"/>.
+        /// </summary>
+        ImmutableArray<ISymbol> ApplicableSymbols { get; }
+
+        /// <summary>
+        /// Dynamically bound arguments, excluding the instance argument.
+        /// </summary>
+        ImmutableArray<IOperation> Arguments { get; }
+        
+        /// <summary>
+        /// Optional argument names for named arguments.
+        /// </summary>
+        ImmutableArray<string> ArgumentNames { get; }
+
+        /// <summary>
+        /// Optional argument ref kinds.
+        /// </summary>
+        ImmutableArray<RefKind> ArgumentRefKinds { get; }
+    }
+}
+

src/Compilers/Core/Portable/Operations/ITypeParameterObjectCreationExpression.cs

 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-using System.Collections.Immutable;
-
 namespace Microsoft.CodeAnalysis.Semantics
 {
+    /// <summary>
+    /// Represents a type parameter object creation expression, i.e. new T(), where T is a type parameter with new constraint.
+    /// </summary>
     /// <remarks>
     /// This interface is reserved for implementation by its associated APIs. We reserve the right to
     /// change it in the future.
     /// </remarks>
     public interface ITypeParameterObjectCreationExpression : IOperation
     {
+        /// <summary>
+        /// Object or collection initializer, if any.
+        /// </summary>
+        IObjectOrCollectionInitializerExpression Initializer { get; }
     }
 }
 

src/Compilers/Core/Portable/Operations/OperationKind.cs

@@ -138,6 +138,8 @@ public enum OperationKind
         NameOfExpression = 0x123,
         /// <summary>Indicates an <see cref="ITupleExpression"/>.</summary>
         TupleExpression = 0x124,
+        /// <summary>Indicates an <see cref="IDynamicObjectCreationExpression"/>.</summary>
+        DynamicObjectCreationExpression = 0x125,
 
         // Expressions that occur only in C#.
 

src/Compilers/Core/Portable/Operations/OperationVisitor.cs

@@ -330,6 +330,11 @@ public virtual void VisitAnonymousObjectCreationExpression(IAnonymousObjectCreat
             DefaultVisit(operation);
         }
 
+        public virtual void VisitDynamicObjectCreationExpression(IDynamicObjectCreationExpression operation)
+        {
+            DefaultVisit(operation);
+        }
+
         public virtual void VisitObjectOrCollectionInitializerExpression(IObjectOrCollectionInitializerExpression operation)
         {
             DefaultVisit(operation);
@@ -795,6 +800,11 @@ public virtual TResult VisitAnonymousObjectCreationExpression(IAnonymousObjectCr
             return DefaultVisit(operation, argument);
         }
 
+        public virtual TResult VisitDynamicObjectCreationExpression(IDynamicObjectCreationExpression operation, TArgument argument)
+        {
+            return DefaultVisit(operation, argument);
+        }
+
         public virtual TResult VisitObjectOrCollectionInitializerExpression(IObjectOrCollectionInitializerExpression operation, TArgument argument)
         {
             return DefaultVisit(operation, argument);

src/Compilers/Core/Portable/Operations/OperationWalker.cs

@@ -16,10 +16,15 @@ public abstract class OperationWalker : OperationVisitor
         {
             foreach (var operation in operations)
             {
-                Visit(operation);
+                VisitOperationArrayElement(operation);
             }
         }
 
+        internal void VisitOperationArrayElement<T>(T operation) where T : IOperation
+        {
+            Visit(operation);
+        }
+
         public override void Visit(IOperation operation)
         {
             if (operation != null)

src/Compilers/Core/Portable/PublicAPI.Unshipped.txt

 *REMOVED*Microsoft.CodeAnalysis.Compilation.Emit(System.IO.Stream peStream, System.IO.Stream pdbStream = null, System.IO.Stream xmlDocumentationStream = null, System.IO.Stream win32Resources = null, System.Collections.Generic.IEnumerable<Microsoft.CodeAnalysis.ResourceDescription> manifestResources = null, Microsoft.CodeAnalysis.Emit.EmitOptions options = null, Microsoft.CodeAnalysis.IMethodSymbol debugEntryPoint = null, System.IO.Stream sourceLinkStream = null, System.Collections.Generic.IEnumerable<Microsoft.CodeAnalysis.EmbeddedText> embeddedTexts = null, System.Threading.CancellationToken cancellationToken = default(System.Threading.CancellationToken)) -> Microsoft.CodeAnalysis.Emit.EmitResult
 *REMOVED*Microsoft.CodeAnalysis.Emit.EmitOptions.EmitOptions(bool metadataOnly = false, Microsoft.CodeAnalysis.Emit.DebugInformationFormat debugInformationFormat = (Microsoft.CodeAnalysis.Emit.DebugInformationFormat)0, string pdbFilePath = null, string outputNameOverride = null, int fileAlignment = 0, ulong baseAddress = 0, bool highEntropyVirtualAddressSpace = false, Microsoft.CodeAnalysis.SubsystemVersion subsystemVersion = default(Microsoft.CodeAnalysis.SubsystemVersion), string runtimeMetadataVersion = null, bool tolerateErrors = false, bool includePrivateMembers = false, System.Collections.Immutable.ImmutableArray<Microsoft.CodeAnalysis.Emit.InstrumentationKind> instrumentationKinds = default(System.Collections.Immutable.ImmutableArray<Microsoft.CodeAnalysis.Emit.InstrumentationKind>)) -> void
 *REMOVED*Microsoft.CodeAnalysis.IOperation.IsInvalid.get -> bool
-Microsoft.CodeAnalysis.IOperation.Children.get -> System.Collections.Generic.IEnumerable<Microsoft.CodeAnalysis.IOperation>
 Microsoft.CodeAnalysis.CommandLineArguments.DisplayLangVersions.get -> bool
 Microsoft.CodeAnalysis.Diagnostics.AnalysisContext.RegisterOperationAction(System.Action<Microsoft.CodeAnalysis.Diagnostics.OperationAnalysisContext> action, params Microsoft.CodeAnalysis.OperationKind[] operationKinds) -> void
 Microsoft.CodeAnalysis.Diagnostics.CompilationStartAnalysisContext.RegisterOperationAction(System.Action<Microsoft.CodeAnalysis.Diagnostics.OperationAnalysisContext> action, params Microsoft.CodeAnalysis.OperationKind[] operationKinds) -> void
@@ -40,6 +39,7 @@ Microsoft.CodeAnalysis.Diagnostics.Telemetry.AnalyzerTelemetryInfo.OperationBloc
 Microsoft.CodeAnalysis.IOperation
 Microsoft.CodeAnalysis.IOperation.Accept(Microsoft.CodeAnalysis.Semantics.OperationVisitor visitor) -> void
 Microsoft.CodeAnalysis.IOperation.Accept<TArgument, TResult>(Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult> visitor, TArgument argument) -> TResult
+Microsoft.CodeAnalysis.IOperation.Children.get -> System.Collections.Generic.IEnumerable<Microsoft.CodeAnalysis.IOperation>
 Microsoft.CodeAnalysis.IOperation.ConstantValue.get -> Microsoft.CodeAnalysis.Optional<object>
 Microsoft.CodeAnalysis.IOperation.Kind.get -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.IOperation.Syntax.get -> Microsoft.CodeAnalysis.SyntaxNode
@@ -66,6 +66,7 @@ Microsoft.CodeAnalysis.OperationKind.ConversionExpression = 258 -> Microsoft.Cod
 Microsoft.CodeAnalysis.OperationKind.DeclarationPattern = 1040 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.DefaultCaseClause = 1042 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.DefaultValueExpression = 512 -> Microsoft.CodeAnalysis.OperationKind
+Microsoft.CodeAnalysis.OperationKind.DynamicObjectCreationExpression = 293 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.EmptyStatement = 9 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.EndStatement = 81 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.EventAssignmentExpression = 283 -> Microsoft.CodeAnalysis.OperationKind
@@ -393,6 +394,8 @@ Microsoft.CodeAnalysis.Semantics.IDeclarationPattern
 Microsoft.CodeAnalysis.Semantics.IDeclarationPattern.DeclaredSymbol.get -> Microsoft.CodeAnalysis.ISymbol
 Microsoft.CodeAnalysis.Semantics.IDefaultCaseClause
 Microsoft.CodeAnalysis.Semantics.IDefaultValueExpression
+Microsoft.CodeAnalysis.Semantics.IDynamicObjectCreationExpression
+Microsoft.CodeAnalysis.Semantics.IDynamicObjectCreationExpression.Initializer.get -> Microsoft.CodeAnalysis.Semantics.IObjectOrCollectionInitializerExpression
 Microsoft.CodeAnalysis.Semantics.IEmptyStatement
 Microsoft.CodeAnalysis.Semantics.IEndStatement
 Microsoft.CodeAnalysis.Semantics.IEventAssignmentExpression
@@ -422,6 +425,12 @@ Microsoft.CodeAnalysis.Semantics.IForWhileUntilLoopStatement
 Microsoft.CodeAnalysis.Semantics.IForWhileUntilLoopStatement.Condition.get -> Microsoft.CodeAnalysis.IOperation
 Microsoft.CodeAnalysis.Semantics.IHasArgumentsExpression
 Microsoft.CodeAnalysis.Semantics.IHasArgumentsExpression.ArgumentsInEvaluationOrder.get -> System.Collections.Immutable.ImmutableArray<Microsoft.CodeAnalysis.Semantics.IArgument>
+Microsoft.CodeAnalysis.Semantics.IHasDynamicArgumentsExpression
+Microsoft.CodeAnalysis.Semantics.IHasDynamicArgumentsExpression.ApplicableSymbols.get -> System.Collections.Immutable.ImmutableArray<Microsoft.CodeAnalysis.ISymbol>
+Microsoft.CodeAnalysis.Semantics.IHasDynamicArgumentsExpression.ArgumentNames.get -> System.Collections.Immutable.ImmutableArray<string>
+Microsoft.CodeAnalysis.Semantics.IHasDynamicArgumentsExpression.ArgumentRefKinds.get -> System.Collections.Immutable.ImmutableArray<Microsoft.CodeAnalysis.RefKind>
+Microsoft.CodeAnalysis.Semantics.IHasDynamicArgumentsExpression.Arguments.get -> System.Collections.Immutable.ImmutableArray<Microsoft.CodeAnalysis.IOperation>
+Microsoft.CodeAnalysis.Semantics.IHasDynamicArgumentsExpression.Name.get -> string
 Microsoft.CodeAnalysis.Semantics.IHasOperatorMethodExpression
 Microsoft.CodeAnalysis.Semantics.IHasOperatorMethodExpression.OperatorMethod.get -> Microsoft.CodeAnalysis.IMethodSymbol
 Microsoft.CodeAnalysis.Semantics.IHasOperatorMethodExpression.UsesOperatorMethod.get -> bool
@@ -554,6 +563,7 @@ Microsoft.CodeAnalysis.Semantics.ITypeOfExpression
 Microsoft.CodeAnalysis.Semantics.ITypeOperationExpression
 Microsoft.CodeAnalysis.Semantics.ITypeOperationExpression.TypeOperand.get -> Microsoft.CodeAnalysis.ITypeSymbol
 Microsoft.CodeAnalysis.Semantics.ITypeParameterObjectCreationExpression
+Microsoft.CodeAnalysis.Semantics.ITypeParameterObjectCreationExpression.Initializer.get -> Microsoft.CodeAnalysis.Semantics.IObjectOrCollectionInitializerExpression
 Microsoft.CodeAnalysis.Semantics.IUnaryOperatorExpression
 Microsoft.CodeAnalysis.Semantics.IUnaryOperatorExpression.Operand.get -> Microsoft.CodeAnalysis.IOperation
 Microsoft.CodeAnalysis.Semantics.IUnaryOperatorExpression.UnaryOperationKind.get -> Microsoft.CodeAnalysis.Semantics.UnaryOperationKind
@@ -722,8 +732,8 @@ abstract Microsoft.CodeAnalysis.Diagnostics.OperationBlockStartAnalysisContext.R
 abstract Microsoft.CodeAnalysis.Diagnostics.OperationBlockStartAnalysisContext.RegisterOperationBlockEndAction(System.Action<Microsoft.CodeAnalysis.Diagnostics.OperationBlockAnalysisContext> action) -> void
 abstract Microsoft.CodeAnalysis.SemanticModel.GetOperationCore(Microsoft.CodeAnalysis.SyntaxNode node, System.Threading.CancellationToken cancellationToken) -> Microsoft.CodeAnalysis.IOperation
 override Microsoft.CodeAnalysis.Optional<T>.ToString() -> string
-override Microsoft.CodeAnalysis.Semantics.OperationWalker.Visit(Microsoft.CodeAnalysis.IOperation operation) -> void
 override Microsoft.CodeAnalysis.Semantics.OperationWalker.DefaultVisit(Microsoft.CodeAnalysis.IOperation operation) -> void
+override Microsoft.CodeAnalysis.Semantics.OperationWalker.Visit(Microsoft.CodeAnalysis.IOperation operation) -> void
 static Microsoft.CodeAnalysis.Semantics.OperationExtensions.Descendants(this Microsoft.CodeAnalysis.IOperation operation) -> System.Collections.Generic.IEnumerable<Microsoft.CodeAnalysis.IOperation>
 static Microsoft.CodeAnalysis.Semantics.OperationExtensions.DescendantsAndSelf(this Microsoft.CodeAnalysis.IOperation operation) -> System.Collections.Generic.IEnumerable<Microsoft.CodeAnalysis.IOperation>
 static Microsoft.CodeAnalysis.Semantics.OperationExtensions.GetDeclaredVariables(this Microsoft.CodeAnalysis.Semantics.IVariableDeclarationStatement declarationStatement) -> System.Collections.Immutable.ImmutableArray<Microsoft.CodeAnalysis.ILocalSymbol>
@@ -770,6 +780,7 @@ virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitConversionExpress
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitDeclarationPattern(Microsoft.CodeAnalysis.Semantics.IDeclarationPattern operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitDefaultCaseClause(Microsoft.CodeAnalysis.Semantics.IDefaultCaseClause operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitDefaultValueExpression(Microsoft.CodeAnalysis.Semantics.IDefaultValueExpression operation) -> void
+virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitDynamicObjectCreationExpression(Microsoft.CodeAnalysis.Semantics.IDynamicObjectCreationExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitEmptyStatement(Microsoft.CodeAnalysis.Semantics.IEmptyStatement operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitEndStatement(Microsoft.CodeAnalysis.Semantics.IEndStatement operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitEventAssignmentExpression(Microsoft.CodeAnalysis.Semantics.IEventAssignmentExpression operation) -> void
@@ -859,6 +870,7 @@ virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.Vi
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitDeclarationPattern(Microsoft.CodeAnalysis.Semantics.IDeclarationPattern operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitDefaultCaseClause(Microsoft.CodeAnalysis.Semantics.IDefaultCaseClause operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitDefaultValueExpression(Microsoft.CodeAnalysis.Semantics.IDefaultValueExpression operation, TArgument argument) -> TResult
+virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitDynamicObjectCreationExpression(Microsoft.CodeAnalysis.Semantics.IDynamicObjectCreationExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitEmptyStatement(Microsoft.CodeAnalysis.Semantics.IEmptyStatement operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitEndStatement(Microsoft.CodeAnalysis.Semantics.IEndStatement operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitEventAssignmentExpression(Microsoft.CodeAnalysis.Semantics.IEventAssignmentExpression operation, TArgument argument) -> TResult

src/Compilers/Core/Portable/Symbols/Attributes/WellKnownAttributeData.cs

@@ -11,12 +11,14 @@ namespace Microsoft.CodeAnalysis
     /// </summary>
     internal abstract class WellKnownAttributeData
     {
+#pragma warning disable CA1802 // Remove suppression once https://github.com/dotnet/roslyn/issues/20894 is fixed
         /// <summary>
         /// Used to distinguish cases when attribute is applied with null value and when attribute is not applied.
         /// For some well-known attributes, the latter case will return string stored in <see cref="StringMissingValue"/>
         /// field.
         /// </summary>
         public static readonly string StringMissingValue = nameof(StringMissingValue);
+#pragma warning restore CA1802
 
 #if DEBUG
         private bool _isSealed;

src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb

@@ -522,10 +522,11 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundNewTOperation(boundNewT As BoundNewT) As ITypeParameterObjectCreationExpression
+            Dim initializer As Lazy(Of IObjectOrCollectionInitializerExpression) = New Lazy(Of IObjectOrCollectionInitializerExpression)(Function() DirectCast(Create(boundNewT.InitializerOpt), IObjectOrCollectionInitializerExpression))
             Dim syntax As SyntaxNode = boundNewT.Syntax
             Dim type As ITypeSymbol = boundNewT.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundNewT.ConstantValueOpt)
-            Return New TypeParameterObjectCreationExpression(syntax, type, constantValue)
+            Return New LazyTypeParameterObjectCreationExpression(initializer, syntax, type, constantValue)
         End Function
 
         Private Function CreateBoundArrayCreationOperation(boundArrayCreation As BoundArrayCreation) As IArrayCreationExpression

src/Compilers/VisualBasic/Test/Semantic/Binding/BindingCollectionInitializerTests.vb

-' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 Imports Microsoft.CodeAnalysis
 Imports Microsoft.CodeAnalysis.Test.Utilities
@@ -1048,6 +1048,20 @@ End Class]]>.Value
 
             Dim expectedOperationTree = <![CDATA[
 ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T, IsInvalid) (Syntax: 'New T() Fro ... , "World!"}')
+  IObjectOrCollectionInitializerExpression (OperationKind.ObjectOrCollectionInitializerExpression, Type: T, IsInvalid) (Syntax: 'From {"Hell ... , "World!"}')
+    Initializers(3):
+        IInvalidExpression (OperationKind.InvalidExpression, Type: System.Void, IsInvalid) (Syntax: '"Hello"')
+          Children(2):
+              IOperation:  (OperationKind.None, IsInvalid) (Syntax: '"Hello"')
+              ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: "Hello", IsInvalid) (Syntax: '"Hello"')
+        IInvalidExpression (OperationKind.InvalidExpression, Type: System.Void, IsInvalid) (Syntax: '" "')
+          Children(2):
+              IOperation:  (OperationKind.None, IsInvalid) (Syntax: '" "')
+              ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: " ", IsInvalid) (Syntax: '" "')
+        IInvalidExpression (OperationKind.InvalidExpression, Type: System.Void, IsInvalid) (Syntax: '"World!"')
+          Children(2):
+              IOperation:  (OperationKind.None, IsInvalid) (Syntax: '"World!"')
+              ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: "World!", IsInvalid) (Syntax: '"World!"')
 ]]>.Value
 
             Dim expectedDiagnostics = <![CDATA[

src/Compilers/VisualBasic/Test/Semantic/Binding/BindingObjectInitializerTests.vb

-' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 Imports System.Linq.Enumerable
 Imports System.Xml.Linq
@@ -810,6 +810,12 @@ End Class]]>.Value
 
             Dim expectedOperationTree = <![CDATA[
 ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T) (Syntax: 'New T() With {.Bar = 23}')
+  IObjectOrCollectionInitializerExpression (OperationKind.ObjectOrCollectionInitializerExpression, Type: T) (Syntax: 'With {.Bar = 23}')
+    Initializers(1):
+        ISimpleAssignmentExpression (OperationKind.SimpleAssignmentExpression, Type: System.Void) (Syntax: '.Bar = 23')
+          Left: IPropertyReferenceExpression: Property IFoo.Bar As System.Int32 (OperationKind.PropertyReferenceExpression, Type: System.Int32) (Syntax: 'Bar')
+              Instance Receiver: IOperation:  (OperationKind.None) (Syntax: 'New T() With {.Bar = 23}')
+          Right: ILiteralExpression (Text: 23) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 23) (Syntax: '23')
 ]]>.Value
 
             Dim expectedDiagnostics = String.Empty
@@ -850,6 +856,7 @@ IObjectCreationExpression (Constructor: Sub C1(Of T)..ctor()) (OperationKind.Obj
             Left: IFieldReferenceExpression: C1(Of T).Field As T (OperationKind.FieldReferenceExpression, Type: T) (Syntax: 'Field')
                 Instance Receiver: IOperation:  (OperationKind.None) (Syntax: 'New C1(Of T ... ld = New T}')
             Right: ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T) (Syntax: 'New T')
+              null
 ]]>.Value
 
             Dim expectedDiagnostics = String.Empty

src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IConversionExpression.vb

-' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 Imports Microsoft.CodeAnalysis.Semantics
 Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
@@ -1681,6 +1681,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: c1 As Module1.C1
     Initializer: IConversionExpression (ConversionKind.Cast, Implicit) (OperationKind.ConversionExpression, Type: Module1.C1) (Syntax: 'New T')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T) (Syntax: 'New T')
+        null
 ]]>.Value
 
             Dim expectedDiagnostics = String.Empty
@@ -1715,6 +1716,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: c1 As Module1.C1
     Initializer: IConversionExpression (ConversionKind.Invalid, Implicit) (OperationKind.ConversionExpression, Type: Module1.C1, IsInvalid) (Syntax: 'New T')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T, IsInvalid) (Syntax: 'New T')
+        null
 ]]>.Value
 
             Dim expectedDiagnostics = <![CDATA[
@@ -1753,6 +1755,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: i1 As Module1.I1
     Initializer: IConversionExpression (ConversionKind.Cast, Implicit) (OperationKind.ConversionExpression, Type: Module1.I1) (Syntax: 'New T')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: T) (Syntax: 'New T')
+        null
 ]]>.Value
 
             Dim expectedDiagnostics = String.Empty
@@ -1780,6 +1783,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: t1 As T
     Initializer: IConversionExpression (ConversionKind.Cast, Implicit) (OperationKind.ConversionExpression, Type: T) (Syntax: 'New U')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: U) (Syntax: 'New U')
+        null
 ]]>.Value
 
             Dim expectedDiagnostics = String.Empty
@@ -1807,6 +1811,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: t1 As T
     Initializer: IConversionExpression (ConversionKind.Invalid, Implicit) (OperationKind.ConversionExpression, Type: T, IsInvalid) (Syntax: 'New U')
         ITypeParameterObjectCreationExpression (OperationKind.TypeParameterObjectCreationExpression, Type: U, IsInvalid) (Syntax: 'New U')
+        null
 ]]>.Value
 
             Dim expectedDiagnostics = <![CDATA[

src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs

@@ -229,8 +229,7 @@ private void Visit(IOperation operation, string header)
             Unindent();
         }
 
-        private void VisitArray<T>(IEnumerable<T> list, string header, bool logElementCount)
-            where T : IOperation
+        private void VisitArrayCommon<T>(IEnumerable<T> list, string header, bool logElementCount, Action<T> arrayElementVisitor)
         {
             Debug.Assert(!string.IsNullOrEmpty(header));
 
@@ -241,7 +240,10 @@ private void VisitArray<T>(IEnumerable<T> list, string header, bool logElementCo
                 LogString($"{header}{elementCount}:");
                 LogNewLine();
                 Indent();
-                VisitArray(list);
+                foreach (var element in list)
+                {
+                    arrayElementVisitor(element);
+                }
                 Unindent();
             }
             else
@@ -253,6 +255,47 @@ private void VisitArray<T>(IEnumerable<T> list, string header, bool logElementCo
             Unindent();
         }
 
+        internal void VisitSymbolArrayElement(ISymbol element)
+        {
+            LogSymbol(element, header: "Symbol");
+            LogNewLine();
+        }
+
+        internal void VisitStringArrayElement(string element)
+        {
+            var valueStr = element != null ? element.ToString() : "null";
+            valueStr = @"""" + valueStr + @"""";
+            LogString(valueStr);
+            LogNewLine();
+        }
+
+        internal void VisitRefKindArrayElement(RefKind element)
+        {
+            LogString(element.ToString());
+            LogNewLine();
+        }
+
+        private void VisitArray<T>(IEnumerable<T> list, string header, bool logElementCount)
+            where T: IOperation
+        {
+            VisitArrayCommon(list, header, logElementCount, VisitOperationArrayElement);
+        }
+
+        private void VisitArray(IEnumerable<ISymbol> list, string header, bool logElementCount)
+        {
+            VisitArrayCommon(list, header, logElementCount, VisitSymbolArrayElement);
+        }
+
+        private void VisitArray(IEnumerable<string> list, string header, bool logElementCount)
+        {
+            VisitArrayCommon(list, header, logElementCount, VisitStringArrayElement);
+        }
+
+        private void VisitArray(IEnumerable<RefKind> list, string header, bool logElementCount)
+        {
+            VisitArrayCommon(list, header, logElementCount, VisitRefKindArrayElement);
+        }
+
         private void VisitInstanceExpression(IOperation instance)
         {
             Visit(instance, header: "Instance Receiver");
@@ -554,6 +597,14 @@ private void VisitArguments(IHasArgumentsExpression operation)
             VisitArray(operation.ArgumentsInEvaluationOrder, "Arguments", logElementCount: true);
         }
 
+        private void VisitDynamicArguments(IHasDynamicArgumentsExpression operation)
+        {
+            VisitArray(operation.ApplicableSymbols, "ApplicableSymbols", logElementCount: true);
+            VisitArray(operation.Arguments, "Arguments", logElementCount: true);
+            VisitArray(operation.ArgumentNames, "ArgumentNames", logElementCount: true);
+            VisitArray(operation.ArgumentRefKinds, "ArgumentRefKinds", logElementCount: true);
+        }
+
         public override void VisitArgument(IArgument operation)
         {
             LogString($"{nameof(IArgument)} (");
@@ -903,6 +954,18 @@ public override void VisitAnonymousObjectCreationExpression(IAnonymousObjectCrea
             VisitArray(operation.Initializers, "Initializers", logElementCount: true);
         }
 
+        public override void VisitDynamicObjectCreationExpression(IDynamicObjectCreationExpression operation)
+        {
+            LogString(nameof(IDynamicObjectCreationExpression));
+
+            var name = operation.Name;
+            LogString($" (Name: {operation.Name})");
+            LogCommonPropertiesAndNewLine(operation);
+
+            VisitDynamicArguments(operation);
+            Visit(operation.Initializer, "Initializer");
+        }
+
         public override void VisitObjectOrCollectionInitializerExpression(IObjectOrCollectionInitializerExpression operation)
         {
             LogString(nameof(IObjectOrCollectionInitializerExpression));
@@ -1061,8 +1124,6 @@ public override void VisitDefaultValueExpression(IDefaultValueExpression operati
         {
             LogString(nameof(IDefaultValueExpression));
             LogCommonPropertiesAndNewLine(operation);
-
-            base.VisitDefaultValueExpression(operation);
         }
 
         public override void VisitTypeParameterObjectCreationExpression(ITypeParameterObjectCreationExpression operation)
@@ -1070,7 +1131,7 @@ public override void VisitTypeParameterObjectCreationExpression(ITypeParameterOb
             LogString(nameof(ITypeParameterObjectCreationExpression));
             LogCommonPropertiesAndNewLine(operation);
 
-            base.VisitTypeParameterObjectCreationExpression(operation);
+            Visit(operation.Initializer);
         }
 
         public override void VisitInvalidStatement(IInvalidStatement operation)

src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs

@@ -435,6 +435,16 @@ public override void VisitAnonymousObjectCreationExpression(IAnonymousObjectCrea
             base.VisitAnonymousObjectCreationExpression(operation);
         }
 
+        public override void VisitDynamicObjectCreationExpression(IDynamicObjectCreationExpression operation)
+        {
+            var name = operation.Name;
+            var applicableSymbols = operation.ApplicableSymbols;
+            var names = operation.ArgumentNames;
+            var refKinds = operation.ArgumentRefKinds;
+
+            base.VisitDynamicObjectCreationExpression(operation);
+        }
+
         public override void VisitObjectOrCollectionInitializerExpression(IObjectOrCollectionInitializerExpression operation)
         {
             base.VisitObjectOrCollectionInitializerExpression(operation);