Add support for ref returning methods and properties in With statem…

…ent.

Fixes dotnet#68194.

src/Compilers/VisualBasic/Portable/Binding/Binder_WithBlock.vb

@@ -102,6 +102,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  expressionPlaceholder As BoundValuePlaceholderBase,
  draftSubstitute As BoundExpression,
  draftInitializers As ImmutableArray(Of BoundExpression),
+ capturedLvalueByRefCallOrProperty As BoundExpression,
  diagnostics As ImmutableBindingDiagnostic(Of AssemblySymbol))
 
  Debug.Assert(originalExpression IsNot Nothing)
@@ -112,6 +113,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  Me.OriginalExpression = originalExpression
  Me.ExpressionPlaceholder = expressionPlaceholder
  Me.DraftSubstitute = draftSubstitute
+ Me.CapturedLvalueByRefCallOrProperty = capturedLvalueByRefCallOrProperty
  Me.DraftInitializers = draftInitializers
  Me.Diagnostics = diagnostics
  End Sub
@@ -140,6 +142,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  ''' </summary>
  Public ReadOnly DraftSubstitute As BoundExpression
 
+ Public ReadOnly CapturedLvalueByRefCallOrProperty As BoundExpression
+
  Public ReadOnly Property ExpressionIsAccessedFromNestedLambda As Boolean
  Get
  Return Me._exprAccessedFromNestedLambda = ThreeState.True
@@ -210,6 +214,13 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  ' NOTE: If the expression is not an l-value we should make an r-value of it
  If Not boundExpression.IsLValue Then
  boundExpression = Me.MakeRValue(boundExpression, diagnostics)
+ Else
+ Dim propertyAccess = TryCast(boundExpression, BoundPropertyAccess)
+
+ If propertyAccess IsNot Nothing Then
+ WarnOnRecursiveAccess(propertyAccess, PropertyAccessKind.Get, diagnostics)
+ boundExpression = propertyAccess.SetAccessKind(PropertyAccessKind.Get)
+ End If
  End If
 
  ' Prepare draft substitute/initializers for expression placeholder;
@@ -218,6 +229,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  Dim result As WithExpressionRewriter.Result =
  (New WithExpressionRewriter(Me._withBlockSyntax.WithStatement)).AnalyzeWithExpression(Me.ContainingMember, boundExpression,
  doNotUseByRefLocal:=True,
+ isDraftRewrite:=True,
  binder:=Me.ContainingBinder,
  preserveIdentityOfLValues:=True)
 
@@ -234,7 +246,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  ' so if the following call fails we can just drop the bound node and diagnostics on the floor
  Interlocked.CompareExchange(Me._withBlockInfo,
  New WithBlockInfo(boundExpression, placeholder,
- result.Expression, result.Initializers, diagnostics.ToReadOnlyAndFree()),
+ result.Expression, result.Initializers, result.CapturedLvalueByRefCallOrProperty, diagnostics.ToReadOnlyAndFree()),
  Nothing)
  End If
 
@@ -302,10 +314,20 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  ' See also comment in PrepareBindingOfOmittedLeft(...)
  diagnostics.AddRange(Me._withBlockInfo.Diagnostics, allowMismatchInDependencyAccumulation:=True)
 
- Return New BoundWithStatement(node,
- Me._withBlockInfo.OriginalExpression,
- boundBlockBinder.BindBlock(node, node.Statements, diagnostics).MakeCompilerGenerated(),
- Me)
+ Dim result = New BoundWithStatement(node,
+ Me._withBlockInfo.OriginalExpression,
+ boundBlockBinder.BindBlock(node, node.Statements, diagnostics).MakeCompilerGenerated(),
+ Me)
+ If Me._withBlockInfo.CapturedLvalueByRefCallOrProperty IsNot Nothing Then
+ Dim containingMethod = TryCast(ContainingMember, MethodSymbol)
+
+ If (containingMethod IsNot Nothing AndAlso (containingMethod.IsIterator OrElse containingMethod.IsAsync)) OrElse
+ result.Binder.ExpressionIsAccessedFromNestedLambda Then
+ ReportDiagnostic(diagnostics, Me._withBlockInfo.CapturedLvalueByRefCallOrProperty.Syntax, ERRID.ERR_UnsupportedRefReturningCallInWithStatement)
+ End If
+ End If
+
+ Return result
  End Function
 
 #End Region

src/Compilers/VisualBasic/Portable/Errors/ErrorFacts.vb

@@ -1362,6 +1362,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  ERRID.ERR_RequiredMembersInvalid,
  ERRID.ERR_NewConstraintCannotHaveRequiredMembers,
  ERRID.ERR_DoNotUseRequiredMember,
+ ERRID.ERR_UnsupportedRefReturningCallInWithStatement,
  ERRID.ERR_NextAvailable,
  ERRID.WRN_UseOfObsoleteSymbol2,
  ERRID.WRN_InvalidOverrideDueToTupleNames2,

src/Compilers/VisualBasic/Portable/Errors/Errors.vb

@@ -1773,7 +1773,9 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  ERR_NewConstraintCannotHaveRequiredMembers = 37324
  ERR_DoNotUseRequiredMember = 37325
 
- ERR_NextAvailable = 37326
+ ERR_UnsupportedRefReturningCallInWithStatement = 37326
+
+ ERR_NextAvailable = 37327
 
  '// WARNINGS BEGIN HERE
  WRN_UseOfObsoleteSymbol2 = 40000

src/Compilers/VisualBasic/Portable/Lowering/LocalRewriter/LocalRewriter_With.vb

@@ -35,6 +35,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  (New WithExpressionRewriter(statementSyntax)).AnalyzeWithExpression(Me._currentMethodOrLambda,
  rewrittenExpression,
  doNotUseByRefLocal,
+ isDraftRewrite:=False,
  Nothing)
 
  RestoreUnstructuredExceptionHandlingContext(node, saveState)

src/Compilers/VisualBasic/Portable/Lowering/WithExpressionRewriter.vb

@@ -17,10 +17,11 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  Private ReadOnly _withSyntax As WithStatementSyntax
 
  Public Structure Result
- Public Sub New(expression As BoundExpression, locals As ImmutableArray(Of LocalSymbol), initializers As ImmutableArray(Of BoundExpression))
+ Public Sub New(expression As BoundExpression, locals As ImmutableArray(Of LocalSymbol), initializers As ImmutableArray(Of BoundExpression), capturedLvalueByRefCallOrProperty As BoundExpression)
  Me.Expression = expression
  Me.Locals = locals
  Me.Initializers = initializers
+ Me.CapturedLvalueByRefCallOrProperty = capturedLvalueByRefCallOrProperty
  End Sub
 
  ''' <summary> Expression to be used instead of With statement expression placeholder </summary>
@@ -31,6 +32,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
 
  ''' <summary> Locals initialization expressions </summary>
  Public ReadOnly Initializers As ImmutableArray(Of BoundExpression)
+
+ Public ReadOnly CapturedLvalueByRefCallOrProperty As BoundExpression
  End Structure
 
  Friend Sub New(withSyntax As WithStatementSyntax)
@@ -44,15 +47,18 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  Public ReadOnly DoNotUseByRefLocal As Boolean
  Public ReadOnly Binder As Binder
  Public ReadOnly PreserveIdentityOfLValues As Boolean
+ Public ReadOnly IsDraftRewrite As Boolean
 
  Private _locals As ArrayBuilder(Of LocalSymbol) = Nothing
  Private _initializers As ArrayBuilder(Of BoundExpression) = Nothing
+ Public _capturedLvalueByRefCallOrProperty As BoundExpression = Nothing
 
- Public Sub New(containingMember As Symbol, doNotUseByRefLocal As Boolean, binder As Binder, preserveIdentityOfLValues As Boolean)
+ Public Sub New(containingMember As Symbol, doNotUseByRefLocal As Boolean, binder As Binder, preserveIdentityOfLValues As Boolean, isDraftRewrite As Boolean)
  Me.ContainingMember = containingMember
  Me.DoNotUseByRefLocal = doNotUseByRefLocal
  Me.Binder = binder
  Me.PreserveIdentityOfLValues = preserveIdentityOfLValues
+ Me.IsDraftRewrite = isDraftRewrite
  End Sub
 
  Public Sub AddLocal(local As LocalSymbol, initializer As BoundExpression)
@@ -73,7 +79,8 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  Public Function CreateResult(expression As BoundExpression) As Result
  Return New Result(expression,
  If(Me._locals Is Nothing, ImmutableArray(Of LocalSymbol).Empty, Me._locals.ToImmutableAndFree()),
- If(Me._initializers Is Nothing, ImmutableArray(Of BoundExpression).Empty, Me._initializers.ToImmutableAndFree()))
+ If(Me._initializers Is Nothing, ImmutableArray(Of BoundExpression).Empty, Me._initializers.ToImmutableAndFree()),
+ Me._capturedLvalueByRefCallOrProperty)
 
  End Function
  End Class
@@ -262,10 +269,11 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  containingMember As Symbol,
  value As BoundExpression,
  doNotUseByRefLocal As Boolean,
+ isDraftRewrite As Boolean,
  binder As Binder,
  Optional preserveIdentityOfLValues As Boolean = False
  ) As Result
- Dim state As New State(containingMember, doNotUseByRefLocal, binder, preserveIdentityOfLValues)
+ Dim state As New State(containingMember, doNotUseByRefLocal, binder, preserveIdentityOfLValues, isDraftRewrite)
  Return state.CreateResult(CaptureWithExpression(value, state))
  End Function
 
@@ -326,6 +334,30 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
  Case BoundKind.FieldAccess
  expression = CaptureFieldAccess(DirectCast(value, BoundFieldAccess), state)
 
+ Case BoundKind.PropertyAccess
+ If Not state.IsDraftRewrite OrElse Not DirectCast(value, BoundPropertyAccess).PropertySymbol.ReturnsByRef Then
+ Throw ExceptionUtilities.UnexpectedValue(value.Kind)
+ End If
+
+ Debug.Assert(state.DoNotUseByRefLocal)
+ If state._capturedLvalueByRefCallOrProperty Is Nothing Then
+ state._capturedLvalueByRefCallOrProperty = value
+ End If
+
+ expression = CaptureInATemp(value, state) ' Capture by value for the purpose of draft rewrite
+
+ Case BoundKind.Call
+ If Not state.IsDraftRewrite OrElse Not DirectCast(value, BoundCall).Method.ReturnsByRef Then
+ Throw ExceptionUtilities.UnexpectedValue(value.Kind)
+ End If
+
+ Debug.Assert(state.DoNotUseByRefLocal)
+ If state._capturedLvalueByRefCallOrProperty Is Nothing Then
+ state._capturedLvalueByRefCallOrProperty = value
+ End If
+
+ expression = CaptureInATemp(value, state) ' Capture by value for the purpose of draft rewrite
+
  Case Else
  Throw ExceptionUtilities.UnexpectedValue(value.Kind)
  End Select

src/Compilers/VisualBasic/Portable/VBResources.resx

@@ -5685,4 +5685,7 @@
  <data name="ERR_DoNotUseRequiredMember" xml:space="preserve">
  <value>'System.Runtime.CompilerServices.RequiredMemberAttribute' is reserved for compiler usage only.</value>
  </data>
+ <data name="ERR_UnsupportedRefReturningCallInWithStatement" xml:space="preserve">
+ <value>A call to a method or property that returns by reference may not be used in this context.</value>
+ </data>
 </root>