Error unity 5

System.MissingMethodException: Método não encontrado: 'Int32 System.Environment.get_CurrentManagedThreadId()'.
   em Boo.Lang.Builtins.<range>d__15..ctor(Int32 <>1__state)
   em Boo.Lang.Builtins.range(Int32 begin, Int32 end, Int32 step)
   em Boo.MonoDevelop.Util.Completion.BooCompletionTextEditorExtension.GetToken(DocumentLocation location)
   em Boo.MonoDevelop.Util.Completion.BooCompletionTextEditorExtension.GetToken(CodeCompletionContext context)
   em Boo.MonoDevelop.Util.Completion.BooCompletionTextEditorExtension.HandleParameterCompletion(CodeCompletionContext context, Char completionChar)
   em MonoDevelop.Ide.Gui.Content.CompletionTextEditorExtension.KeyPress(Key key, Char keyChar, ModifierType modifier) na c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Content\CompletionTextEditorExtension.cs:linha 140
   em MonoDevelop.Ide.Gui.Content.TextEditorExtension.KeyPress(Key key, Char keyChar, ModifierType modifier) na c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Content\TextEditorExtension.cs:linha 109
   em MonoDevelop.Ide.Gui.Content.TextEditorExtension.KeyPress(Key key, Char keyChar, ModifierType modifier) na c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Content\TextEditorExtension.cs:linha 109
   em MonoDevelop.Ide.Gui.Content.TextEditorExtension.KeyPress(Key key, Char keyChar, ModifierType modifier) na c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Content\TextEditorExtension.cs:linha 109
   em MonoDevelop.Ide.Gui.Content.TextEditorExtension.KeyPress(Key key, Char keyChar, ModifierType modifier) na c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Content\TextEditorExtension.cs:linha 109
   em MonoDevelop.Debugger.ExceptionCaughtTextEditorExtension.KeyPress(Key key, Char keyChar, ModifierType modifier) na c:\buildslave\monodevelop\build\monodevelop\main\src\addins\MonoDevelop.Debugger\MonoDevelop.Debugger\ExceptionCaughtDialog.cs:linha 439
   em MonoDevelop.Ide.Gui.Content.TextEditorExtension.KeyPress(Key key, Char keyChar, ModifierType modifier) na c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Content\TextEditorExtension.cs:linha 109
   em MonoDevelop.Ide.Gui.Content.TextEditorExtension.KeyPress(Key key, Char keyChar, ModifierType modifier) na c:\buildslave\monodevelop\build\monodevelop\main\src\core\MonoDevelop.Ide\MonoDevelop.Ide.Gui.Content\TextEditorExtension.cs:linha 109
   em MonoDevelop.SourceEditor.ExtensibleTextEditor.ExtensionKeyPress(Key key, UInt32 ch, ModifierType state) na c:\buildslave\monodevelop\build\monodevelop\main\src\addins\MonoDevelop.SourceEditor2\MonoDevelop.SourceEditor\ExtensibleTextEditor.cs:linha 249