Moved synthetic receiver for property initializers to use the correct type in C#.

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

@@ -4020,6 +4020,7 @@ private BoundExpression MakeBadExpressionForObjectCreation(ObjectCreationExpress
                 expanded,
                 argsToParamsOpt,
                 resultKind,
+                implicitReceiver.Type,
                 binderOpt: this,
                 type: boundMember.Type,
                 hasErrors: hasErrors);

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

@@ -1322,6 +1322,7 @@
     <Field Name="Expanded" Type="bool"/>
     <Field Name="ArgsToParamsOpt" Type="ImmutableArray&lt;int&gt;" Null="allow"/>
     <Field Name="ResultKind" PropertyOverrides="true" Type="LookupResultKind"/>
+    <Field Name="InstanceSymbol" Type="TypeSymbol" Null="disallow"/>
     
     <!-- BinderOpt is a temporary solution for IOperation implementation and should probably be removed in the future -->
     <!-- Tracked by https://github.com/dotnet/roslyn/issues/20787 -->

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

@@ -4765,11 +4765,12 @@ public BoundObjectInitializerExpression Update(ImmutableArray<BoundExpression> i
 
     internal sealed partial class BoundObjectInitializerMember : BoundExpression
     {
-        public BoundObjectInitializerMember(SyntaxNode syntax, Symbol memberSymbol, ImmutableArray<BoundExpression> arguments, ImmutableArray<string> argumentNamesOpt, ImmutableArray<RefKind> argumentRefKindsOpt, bool expanded, ImmutableArray<int> argsToParamsOpt, LookupResultKind resultKind, Binder binderOpt, TypeSymbol type, bool hasErrors = false)
+        public BoundObjectInitializerMember(SyntaxNode syntax, Symbol memberSymbol, ImmutableArray<BoundExpression> arguments, ImmutableArray<string> argumentNamesOpt, ImmutableArray<RefKind> argumentRefKindsOpt, bool expanded, ImmutableArray<int> argsToParamsOpt, LookupResultKind resultKind, TypeSymbol instanceSymbol, Binder binderOpt, TypeSymbol type, bool hasErrors = false)
             : base(BoundKind.ObjectInitializerMember, syntax, type, hasErrors || arguments.HasErrors())
         {
 
             Debug.Assert(!arguments.IsDefault, "Field 'arguments' cannot be null (use Null=\"allow\" in BoundNodes.xml to remove this check)");
+            Debug.Assert(instanceSymbol != null, "Field 'instanceSymbol' 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.MemberSymbol = memberSymbol;
@@ -4779,6 +4780,7 @@ public BoundObjectInitializerMember(SyntaxNode syntax, Symbol memberSymbol, Immu
             this.Expanded = expanded;
             this.ArgsToParamsOpt = argsToParamsOpt;
             this._ResultKind = resultKind;
+            this.InstanceSymbol = instanceSymbol;
             this.BinderOpt = binderOpt;
         }
 
@@ -4798,6 +4800,8 @@ public BoundObjectInitializerMember(SyntaxNode syntax, Symbol memberSymbol, Immu
         private readonly LookupResultKind _ResultKind;
         public override LookupResultKind ResultKind { get { return _ResultKind;} }
 
+        public TypeSymbol InstanceSymbol { get; }
+
         public Binder BinderOpt { get; }
 
         public override BoundNode Accept(BoundTreeVisitor visitor)
@@ -4805,11 +4809,11 @@ public override BoundNode Accept(BoundTreeVisitor visitor)
             return visitor.VisitObjectInitializerMember(this);
         }
 
-        public BoundObjectInitializerMember Update(Symbol memberSymbol, ImmutableArray<BoundExpression> arguments, ImmutableArray<string> argumentNamesOpt, ImmutableArray<RefKind> argumentRefKindsOpt, bool expanded, ImmutableArray<int> argsToParamsOpt, LookupResultKind resultKind, Binder binderOpt, TypeSymbol type)
+        public BoundObjectInitializerMember Update(Symbol memberSymbol, ImmutableArray<BoundExpression> arguments, ImmutableArray<string> argumentNamesOpt, ImmutableArray<RefKind> argumentRefKindsOpt, bool expanded, ImmutableArray<int> argsToParamsOpt, LookupResultKind resultKind, TypeSymbol instanceSymbol, Binder binderOpt, TypeSymbol type)
         {
-            if (memberSymbol != this.MemberSymbol || arguments != this.Arguments || argumentNamesOpt != this.ArgumentNamesOpt || argumentRefKindsOpt != this.ArgumentRefKindsOpt || expanded != this.Expanded || argsToParamsOpt != this.ArgsToParamsOpt || resultKind != this.ResultKind || binderOpt != this.BinderOpt || type != this.Type)
+            if (memberSymbol != this.MemberSymbol || arguments != this.Arguments || argumentNamesOpt != this.ArgumentNamesOpt || argumentRefKindsOpt != this.ArgumentRefKindsOpt || expanded != this.Expanded || argsToParamsOpt != this.ArgsToParamsOpt || resultKind != this.ResultKind || instanceSymbol != this.InstanceSymbol || binderOpt != this.BinderOpt || type != this.Type)
             {
-                var result = new BoundObjectInitializerMember(this.Syntax, memberSymbol, arguments, argumentNamesOpt, argumentRefKindsOpt, expanded, argsToParamsOpt, resultKind, binderOpt, type, this.HasErrors);
+                var result = new BoundObjectInitializerMember(this.Syntax, memberSymbol, arguments, argumentNamesOpt, argumentRefKindsOpt, expanded, argsToParamsOpt, resultKind, instanceSymbol, binderOpt, type, this.HasErrors);
                 result.WasCompilerGenerated = this.WasCompilerGenerated;
                 return result;
             }
@@ -9044,8 +9048,9 @@ public override BoundNode VisitObjectInitializerExpression(BoundObjectInitialize
         public override BoundNode VisitObjectInitializerMember(BoundObjectInitializerMember node)
         {
             ImmutableArray<BoundExpression> arguments = (ImmutableArray<BoundExpression>)this.VisitList(node.Arguments);
+            TypeSymbol instanceSymbol = this.VisitType(node.InstanceSymbol);
             TypeSymbol type = this.VisitType(node.Type);
-            return node.Update(node.MemberSymbol, arguments, node.ArgumentNamesOpt, node.ArgumentRefKindsOpt, node.Expanded, node.ArgsToParamsOpt, node.ResultKind, node.BinderOpt, type);
+            return node.Update(node.MemberSymbol, arguments, node.ArgumentNamesOpt, node.ArgumentRefKindsOpt, node.Expanded, node.ArgsToParamsOpt, node.ResultKind, instanceSymbol, node.BinderOpt, type);
         }
         public override BoundNode VisitDynamicObjectInitializerMember(BoundDynamicObjectInitializerMember node)
         {
@@ -10449,6 +10454,7 @@ public override TreeDumperNode VisitObjectInitializerMember(BoundObjectInitializ
                 new TreeDumperNode("expanded", node.Expanded, null),
                 new TreeDumperNode("argsToParamsOpt", node.ArgsToParamsOpt, null),
                 new TreeDumperNode("resultKind", node.ResultKind, null),
+                new TreeDumperNode("instanceSymbol", node.InstanceSymbol, null),
                 new TreeDumperNode("binderOpt", node.BinderOpt, null),
                 new TreeDumperNode("type", node.Type, null)
             }

src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_ObjectOrCollectionInitializerExpression.cs

@@ -239,6 +239,7 @@ private BoundExpression MakeCollectionInitializer(BoundExpression rewrittenRecei
                                 memberInit.Expanded,
                                 memberInit.ArgsToParamsOpt,
                                 memberInit.ResultKind,
+                                memberInit.InstanceSymbol,
                                 memberInit.BinderOpt,
                                 memberInit.Type);
                         }

src/Compilers/CSharp/Portable/Lowering/MethodToClassRewriter.cs

@@ -633,7 +633,7 @@ public override BoundNode VisitObjectInitializerMember(BoundObjectInitializerMem
                     break;
             }
 
-            return node.Update(member, arguments, node.ArgumentNamesOpt, node.ArgumentRefKindsOpt, node.Expanded, node.ArgsToParamsOpt, node.ResultKind, node.BinderOpt, type);
+            return node.Update(member, arguments, node.ArgumentNamesOpt, node.ArgumentRefKindsOpt, node.Expanded, node.ArgsToParamsOpt, node.ResultKind, node.InstanceSymbol, node.BinderOpt, type);
         }
 
         private static bool BaseReferenceInReceiverWasRewritten(BoundExpression originalReceiver, BoundExpression rewrittenReceiver)

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

@@ -535,7 +535,7 @@ private IMemberReferenceExpression CreateBoundObjectInitializerMemberOperation(B
             Lazy<IOperation> instance = new Lazy<IOperation>(() => new InstanceReferenceExpression(
                 semanticModel: _semanticModel,
                 syntax: boundObjectInitializerMember.Syntax,
-                type: boundObjectInitializerMember.MemberSymbol.ContainingType,
+                type: boundObjectInitializerMember.InstanceSymbol,
                 constantValue: default(Optional<object>),
                 isImplicit: boundObjectInitializerMember.WasCompilerGenerated));
 

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

@@ -10,7 +10,7 @@ public partial class IOperationTests : SemanticModelTestBase
     {
         [CompilerTrait(CompilerFeature.IOperation)]
         [Fact]
-        public void IPropertyReferenceExpression_PropertyReferenceInDerivedTypeUsesBaseTypeAsInstanceType()
+        public void IPropertyReferenceExpression_PropertyReferenceInDerivedTypeUsesDerivedTypeAsInstanceType()
         {
             string source = @"
 class C
@@ -33,7 +33,7 @@ class C2 : C1
             string expectedOperationTree = @"
 ISimpleAssignmentExpression (OperationKind.SimpleAssignmentExpression, Type: System.Int32) (Syntax: 'P1 = 1')
   Left: IPropertyReferenceExpression: System.Int32 C1.P1 { get; set; } (OperationKind.PropertyReferenceExpression, Type: System.Int32) (Syntax: 'P1')
-      Instance Receiver: IInstanceReferenceExpression (OperationKind.InstanceReferenceExpression, Type: C1) (Syntax: 'P1')
+      Instance Receiver: IInstanceReferenceExpression (OperationKind.InstanceReferenceExpression, Type: C2) (Syntax: 'P1')
   Right: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Int32, Constant: 1) (Syntax: '1')
 ";
             var expectedDiagnostics = DiagnosticDescription.None;