VBNC99999 Unexpected error: There has been an internal error in the compiler

[5e9148d9]

I failed to compile VB.net library under Ubuntu
When I run the command

vbnc *.vb -t:library -out:mylibrary.dll

I am getting the error

Visual Basic.Net Compiler version 0.0.0.5943 (Mono 4.0.1 - tarball)
Copyright (C) 2004-2010 Rolf Bjarne Kvinge. All rights reserved.

vbnc : Command line : error VBNC99999: Unexpected error: There has been an internal error in the compiler: Location: /projects/PRJ/VB.NET/APP/1File.vb (6,49)
  at vbnc.tm.AcceptIfNotInternalError (vbnc.KS Special) [0x0003a] in <e66a75bc246447ad90851a2f40b061fc>:0
  at vbnc.Parser.ParseImplementsClause (vbnc.ParsedObject Parent) [0x00017] in <e66a75bc246447ad90851a2f40b061fc>:0
  at vbnc.Parser.ParseRegularPropertyMemberDeclaration (vbnc.TypeDeclaration Parent, vbnc.ParseAttributableInfo Info) [0x0009f] in <e66a75bc246447ad90851a2f40b061fc>:0
  at vbnc.Parser.ParseTypeMembers (vbnc.TypeDeclaration Parent) [0x0056c] in <e66a75bc246447ad90851a2f40b061fc>:0
  at vbnc.Parser.ParseClassDeclaration (vbnc.ParsedObject Parent, vbnc.Attributes Attributes, System.String Namespace) [0x00299] in <e66a75bc246447ad90851a2f40b061fc>:0
  at vbnc.Parser.ParseTypeDeclaration (vbnc.ParsedObject Parent, vbnc.Attributes Attributes, System.String Namespace) [0x00013] in <e66a75bc246447ad90851a2f40b061fc>:0
  at vbnc.Parser.ParseAssemblyMembers (vbnc.AssemblyDeclaration Parent, System.String RootNamespace) [0x00213] in <e66a75bc246447ad90851a2f40b061fc>:0
  at vbnc.Parser.ParseAssemblyDeclaration (System.String RootNamespace, vbnc.AssemblyDeclaration assembly) [0x000b0] in <e66a75bc246447ad90851a2f40b061fc>:0
  at vbnc.Parser.Parse (System.String RootNamespace, vbnc.AssemblyDeclaration assembly) [0x00007] in <e66a75bc246447ad90851a2f40b061fc>:0
  at vbnc.Compiler.Compile_Parse () [0x000d8] in <e66a75bc246447ad90851a2f40b061fc>:0
  at vbnc.Compiler.Compile () [0x002e1] in <e66a75bc246447ad90851a2f40b061fc>:0
Compilation took 00:00:00.1671690

File 1File.vb

Option Explicit On

Partial Public Class AngleWINStub
        Inherits WindowStub

    Public Property OkBTN As CommandButtonStub = New CommandButtonStub()
    Public Property A60LBL As LabelStub = New LabelStub()
    Public Property A45LBL As LabelStub = New LabelStub()
    Public Property Label1 As LabelStub = New LabelStub()

End Class

Under windows in Visual Studio with target .NET core it compiles without errors.

I am using Ubuntu 20.04 and packages "mono-complete" and "mono-vbnc".