Fix syntax node for the EventReference in IEventAssignmentOperation

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

@@ -7,6 +7,7 @@
 using System.Linq;
 using Microsoft.CodeAnalysis.CSharp;
 using Microsoft.CodeAnalysis.CSharp.Symbols;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Roslyn.Utilities;
 
@@ -358,16 +359,16 @@ private IEventAssignmentExpression CreateBoundEventAssignmentOperatorOperation(B
             SyntaxNode syntax = boundEventAssignmentOperator.Syntax;
             Lazy<IEventReferenceExpression> eventReference = new Lazy<IEventReferenceExpression>(() =>
             {
+                // BoundEventAssignmentOperator doesn't hold on to BoundEventAccess provided during binding.
+                // Based on the implementation of those two bound node types, the following data can be retrieved w/o changing BoundEventAssignmentOperator:
+                //  1. the type of BoundEventAccess is the type of the event symbol.
+                //  2. the constant value of BoundEventAccess is always null.
+                //  3. the syntax of the boundEventAssignmentOperator is always AssignmentExpressionSyntax, so the syntax for the event reference would be the LHS of the assignment.
                 IEventSymbol @event = boundEventAssignmentOperator.Event;
                 Lazy<IOperation> instance = new Lazy<IOperation>(() => Create(boundEventAssignmentOperator.Event.IsStatic ? null : boundEventAssignmentOperator.ReceiverOpt));
-                ISymbol member = boundEventAssignmentOperator.Event;
-                // BoundEventAssignmentOperator doesn't hold on to all the data from the provided BoundEventAccess during binding.
-                // Based on the implementation of those two bound node types, the following data can be retieved w/o changing BoundEventAssignmentOperator:
-                //  1. The type of BoundEventAccess is the type of the event symbol.
-                //  2. the constant value of BoundEventAccess is always null.
-                // However, we can't reliably get the syntax node for the BoundEventAccess w/o changing BoundEventAssignmentOperator, so the syntax of entire
-                // BoundEventAssignmentOperator is used instead.
-                return new LazyEventReferenceExpression(@event, instance, @event, syntax, @event.Type, ConvertToOptional(null));
+                SyntaxNode eventAccessSyntax = ((AssignmentExpressionSyntax)syntax).Left;
+
+                return new LazyEventReferenceExpression(@event, instance, @event, eventAccessSyntax, @event.Type, ConvertToOptional(null));
             });
                 
             Lazy<IOperation> handlerValue = new Lazy<IOperation>(() => Create(boundEventAssignmentOperator.Argument));

src/Compilers/CSharp/Test/Semantic/Diagnostics/OperationAnalyzerTests.cs

@@ -1485,11 +1485,11 @@ void Foo()
             CreateCompilationWithMscorlib45(source, parseOptions: TestOptions.RegularWithIOperationFeature)
             .VerifyDiagnostics(Diagnostic(ErrorCode.WRN_UnreferencedEvent, "E").WithArguments("D.E").WithLocation(6, 32))
             .VerifyAnalyzerDiagnostics(new DiagnosticAnalyzer[] { new StaticMemberTestAnalyzer() }, null, null, false,
-                Diagnostic(StaticMemberTestAnalyzer.StaticMemberDescriptor.Id, "C.E += D.Method").WithLocation(23, 9),
+                Diagnostic(StaticMemberTestAnalyzer.StaticMemberDescriptor.Id, "C.E").WithLocation(23, 9),
                 Diagnostic(StaticMemberTestAnalyzer.StaticMemberDescriptor.Id, "D.Method").WithLocation(23, 16),
                 Diagnostic(StaticMemberTestAnalyzer.StaticMemberDescriptor.Id, "C.E").WithLocation(24, 9),
                 Diagnostic(StaticMemberTestAnalyzer.StaticMemberDescriptor.Id, "C.Bar()").WithLocation(25, 9),
-                Diagnostic(StaticMemberTestAnalyzer.StaticMemberDescriptor.Id, "D.E += () => { }").WithLocation(27, 9),
+                Diagnostic(StaticMemberTestAnalyzer.StaticMemberDescriptor.Id, "D.E").WithLocation(27, 9),
                 Diagnostic(StaticMemberTestAnalyzer.StaticMemberDescriptor.Id, "D.Field").WithLocation(28, 9),
                 Diagnostic(StaticMemberTestAnalyzer.StaticMemberDescriptor.Id, "D.Property").WithLocation(29, 17),
                 Diagnostic(StaticMemberTestAnalyzer.StaticMemberDescriptor.Id, "D.Method()").WithLocation(30, 9)

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

@@ -33,7 +33,7 @@ void M()
 ";
             string expectedOperationTree = @"
 IEventAssignmentExpression (EventAdd)) (OperationKind.EventAssignmentExpression, Type: System.Void) (Syntax: 't.MyEvent += Handler')
-  Event Reference: IEventReferenceExpression: event System.EventHandler Test.MyEvent (OperationKind.EventReferenceExpression, Type: System.EventHandler) (Syntax: 't.MyEvent += Handler')
+  Event Reference: IEventReferenceExpression: event System.EventHandler Test.MyEvent (OperationKind.EventReferenceExpression, Type: System.EventHandler) (Syntax: 't.MyEvent')
       Instance Receiver: ILocalReferenceExpression: t (OperationKind.LocalReferenceExpression, Type: Test) (Syntax: 't')
   Handler: IMethodBindingExpression: void C.Handler(System.Object sender, System.EventArgs e) (OperationKind.MethodBindingExpression, Type: System.EventHandler) (Syntax: 'Handler')
       Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C) (Syntax: 'Handler')
@@ -69,7 +69,7 @@ void M()
 ";
             string expectedOperationTree = @"
 IEventAssignmentExpression (EventRemove)) (OperationKind.EventAssignmentExpression, Type: System.Void) (Syntax: 't.MyEvent -= null')
-  Event Reference: IEventReferenceExpression: event System.EventHandler Test.MyEvent (OperationKind.EventReferenceExpression, Type: System.EventHandler) (Syntax: 't.MyEvent -= null')
+  Event Reference: IEventReferenceExpression: event System.EventHandler Test.MyEvent (OperationKind.EventReferenceExpression, Type: System.EventHandler) (Syntax: 't.MyEvent')
       Instance Receiver: ILocalReferenceExpression: t (OperationKind.LocalReferenceExpression, Type: Test) (Syntax: 't')
   Handler: IConversionExpression (ConversionKind.Cast, Implicit) (OperationKind.ConversionExpression, Type: System.EventHandler, Constant: null) (Syntax: 'null')
       ILiteralExpression (Text: null) (OperationKind.LiteralExpression, Type: null, Constant: null) (Syntax: 'null')
@@ -108,7 +108,7 @@ void M()
 ";
             string expectedOperationTree = @"
 IEventAssignmentExpression (EventAdd)) (OperationKind.EventAssignmentExpression, Type: System.Void) (Syntax: 'Test.MyEvent += Handler')
-  Event Reference: IEventReferenceExpression: event System.EventHandler Test.MyEvent (Static) (OperationKind.EventReferenceExpression, Type: System.EventHandler) (Syntax: 'Test.MyEvent += Handler')
+  Event Reference: IEventReferenceExpression: event System.EventHandler Test.MyEvent (Static) (OperationKind.EventReferenceExpression, Type: System.EventHandler) (Syntax: 'Test.MyEvent')
       Instance Receiver: null
   Handler: IMethodBindingExpression: void C.Handler(System.Object sender, System.EventArgs e) (OperationKind.MethodBindingExpression, Type: System.EventHandler) (Syntax: 'Handler')
       Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C) (Syntax: 'Handler')
@@ -147,7 +147,7 @@ void M()
 ";
             string expectedOperationTree = @"
 IEventAssignmentExpression (EventRemove)) (OperationKind.EventAssignmentExpression, Type: System.Void) (Syntax: 'Test.MyEvent -= Handler')
-  Event Reference: IEventReferenceExpression: event System.EventHandler Test.MyEvent (Static) (OperationKind.EventReferenceExpression, Type: System.EventHandler) (Syntax: 'Test.MyEvent -= Handler')
+  Event Reference: IEventReferenceExpression: event System.EventHandler Test.MyEvent (Static) (OperationKind.EventReferenceExpression, Type: System.EventHandler) (Syntax: 'Test.MyEvent')
       Instance Receiver: null
   Handler: IMethodBindingExpression: void C.Handler(System.Object sender, System.EventArgs e) (OperationKind.MethodBindingExpression, Type: System.EventHandler) (Syntax: 'Handler')
       Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C) (Syntax: 'Handler')
@@ -187,7 +187,7 @@ void M()
 ";
             string expectedOperationTree = @"
 IEventAssignmentExpression (EventAdd)) (OperationKind.EventAssignmentExpression, Type: System.Void, IsInvalid) (Syntax: 't.MyEvent += Handler')
-  Event Reference: IEventReferenceExpression: event System.EventHandler Test.MyEvent (OperationKind.EventReferenceExpression, Type: System.EventHandler, IsInvalid) (Syntax: 't.MyEvent += Handler')
+  Event Reference: IEventReferenceExpression: event System.EventHandler Test.MyEvent (OperationKind.EventReferenceExpression, Type: System.EventHandler, IsInvalid) (Syntax: 't.MyEvent')
       Instance Receiver: ILocalReferenceExpression: t (OperationKind.LocalReferenceExpression, Type: Test, IsInvalid) (Syntax: 't')
   Handler: IConversionExpression (ConversionKind.Invalid, Implicit) (OperationKind.ConversionExpression, Type: System.EventHandler, IsInvalid) (Syntax: 'Handler')
       IOperation:  (OperationKind.None, IsInvalid) (Syntax: 'Handler')

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

@@ -1011,7 +1011,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundAddHandlerStatementOperation(boundAddHandlerStatement As BoundAddHandlerStatement) As IExpressionStatement
-            Dim expression As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() GetAddHandlerStatementExpression(boundAddHandlerStatement))
+            Dim expression As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() GetAddRemoveHandlerStatementExpression(boundAddHandlerStatement))
             Dim syntax As SyntaxNode = boundAddHandlerStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
@@ -1019,7 +1019,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundRemoveHandlerStatementOperation(boundRemoveHandlerStatement As BoundRemoveHandlerStatement) As IExpressionStatement
-            Dim expression As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() GetRemoveStatementExpression(boundRemoveHandlerStatement))
+            Dim expression As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() GetAddRemoveHandlerStatementExpression(boundRemoveHandlerStatement))
             Dim syntax As SyntaxNode = boundRemoveHandlerStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()

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

@@ -406,18 +406,12 @@ Namespace Microsoft.CodeAnalysis.Semantics
                             constantValue:=Nothing)
         End Function
 
-        Private Function GetAddHandlerStatementExpression(statement As BoundAddHandlerStatement) As IOperation
+        Private Function GetAddRemoveHandlerStatementExpression(statement As BoundAddRemoveHandlerStatement) As IOperation
             Dim eventAccess As BoundEventAccess = TryCast(statement.EventAccess, BoundEventAccess)
             Dim eventReference = If(eventAccess Is Nothing, Nothing, CreateBoundEventAccessOperation(eventAccess))
+            Dim adds = TypeOf statement Is BoundAddHandlerStatement
             Return New EventAssignmentExpression(
-                        eventReference, Create(statement.Handler), adds:=True, syntax:=statement.Syntax, type:=Nothing, constantValue:=Nothing)
-        End Function
-
-        Private Function GetRemoveStatementExpression(statement As BoundRemoveHandlerStatement) As IOperation
-            Dim eventAccess As BoundEventAccess = TryCast(statement.EventAccess, BoundEventAccess)
-            Dim eventReference = If(eventAccess Is Nothing, Nothing, CreateBoundEventAccessOperation(eventAccess))
-            Return New EventAssignmentExpression(
-                eventReference, Create(statement.Handler), adds:=False, syntax:=statement.Syntax, type:=Nothing, constantValue:=Nothing)
+                eventReference, Create(statement.Handler), adds:=adds, syntax:=statement.Syntax, type:=Nothing, constantValue:=Nothing)
         End Function
 
         Private Shared Function GetConversionKind(kind As VisualBasic.ConversionKind) As Semantics.ConversionKind

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

@@ -16,7 +16,7 @@ Class TestClass
     
     Event TestEvent As Action
 
-    Sub Add(receiver As TestClass)
+    Sub Add()
         AddHandler TestEvent, AddressOf M'BIND:"AddHandler TestEvent, AddressOf M"
     End Sub
 
@@ -48,7 +48,7 @@ Class TestClass
     
     Event TestEvent As Action
 
-    Sub Remove(receiver As TestClass)
+    Sub Remove()
         RemoveHandler TestEvent, AddressOf M'BIND:"RemoveHandler TestEvent, AddressOf M"
     End Sub
 
@@ -80,7 +80,7 @@ Class TestClass
     
     Shared Event TestEvent As Action
 
-    Sub Add(receiver As TestClass)
+    Sub Add()
         AddHandler TestEvent, AddressOf M'BIND:"AddHandler TestEvent, AddressOf M"
     End Sub
 
@@ -112,7 +112,7 @@ Class TestClass
     
     Shared Event TestEvent As Action
 
-    Sub Remove(receiver As TestClass)
+    Sub Remove()
         RemoveHandler TestEvent, AddressOf M'BIND:"RemoveHandler TestEvent, AddressOf M"
     End Sub
 
@@ -144,7 +144,7 @@ Class TestClass
     
     Shared Event TestEvent As Action
 
-    Sub Remove(receiver As TestClass)
+    Sub Remove()
         RemoveHandler TestEvent, AddressOf M'BIND:"RemoveHandler TestEvent, AddressOf M"
     End Sub