' Licensed to the .NET Foundation under one or more agreements.
' The .NET Foundation licenses this file to you under the MIT license.
' See the LICENSE file in the project root for more information.

Imports System.Collections.Generic
Imports Microsoft.CodeAnalysis.Text
Imports Microsoft.CodeAnalysis.VisualBasic.Symbols
Imports Microsoft.CodeAnalysis.VisualBasic.Syntax

Namespace Microsoft.CodeAnalysis.VisualBasic

    ''' <summary>
    ''' This binder is for binding the initializer of an implicitly typed 
    ''' local variable. While binding an implicitly typed local variable
    ''' this binder is used to break cycles.
    ''' </summary>
    Friend NotInheritable Class LocalInProgressBinder
        Inherits Binder

        ' In certain scenarios we might find ourselves in loops, like
        ' 
        ' dim x = y
        ' dim y = M(x)
        '
        ' We break the cycle by ensuring that an initializer which illegally refers
        ' forwards to an in-scope local does not attempt to work out the type of the
        ' forward local. However, just to make sure, we also keep track of every
        ' local whose type we are attempting to infer. (This might be necessary for
        ' "script class" scenarios where local vars are actually fields.)
        Private ReadOnly _symbols As ConsList(Of LocalSymbol)

        Public Sub New(containingBinder As Binder, symbol As LocalSymbol)
            MyBase.New(containingBinder)
            Me._symbols = New ConsList(Of LocalSymbol)(symbol, containingBinder.ImplicitlyTypedLocalsBeingBound)
        End Sub

        Public Overrides ReadOnly Property ImplicitlyTypedLocalsBeingBound As ConsList(Of LocalSymbol)
            Get
                Return Me._symbols
            End Get

        End Property

    End Class

End Namespace