missingexpression.vb

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' 
' Visual Basic.Net Compiler
' Copyright (C) 2004 - 2007 Rolf Bjarne Kvinge, [e-mail]
' 
' This library is free software; you can redistribute it and/or
' modify it under the terms of the GNU Lesser General Public
' License as published by the Free Software Foundation; either
' version 2.1 of the License, or (at your option) any later version.
' 
' This library is distributed in the hope that it will be useful,
' but WITHOUT ANY WARRANTY; without even the implied warranty of
' MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
' Lesser General Public License for more details.
' 
' You should have received a copy of the GNU Lesser General Public
' License along with this library; if not, write to the Free Software
' Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
' 

''' <summary>
''' Represents the missing argument in a call to a method with optional parameters.
''' </summary>
''' <remarks></remarks>
Public Class MissingExpression
    Inherits Expression

    Protected Overrides Function GenerateCodeInternal(ByVal Info As EmitInfo) As Boolean
        Helper.Stop() 'A missing expression doesn't know how to emit itself.
    End Function

    Overrides ReadOnly Property ExpressionType() As Type
        Get
            Return New MissingType(Me.Compiler)
        End Get
    End Property

    Protected Overrides Function ResolveExpressionInternal(ByVal Info As ResolveInfo) As Boolean
        Return True
    End Function

    Sub New(ByVal Parent As Expression)
        MyBase.New(Parent)
    End Sub

#If DEBUG Then
    Public Overrides Sub Dump(ByVal Dumper As IndentedTextWriter)
        Dumper.Write("<Missing>")
    End Sub
#End If
End Class