anchor.diff:      member __.Value: Expression = value
       member __.Computed: bool = computed
       member __.Shorthand: bool = shorthand
  -    // member __.Decorators: Decorator array option = decorators
   
   type ObjectMethodKind = ObjectGetter | ObjectSetter | ObjectMeth
   
  
positive.code:     member __.Abstract: bool option = ``abstract``
      member __.ReturnType: TypeAnnotation option = returnType
      member __.TypeParameters: TypeParameterDeclaration option = typeParameters
      // member __.Decorators: Decorator array option = decorators
      // This appears in astexplorer.net but it's not documented
      // member __.Expression: bool = false
  
  
negative.code:     member __.Left: Pattern = left
      member __.Right: Expression = right
      member __.TypeAnnotation: TypeAnnotation option = typeAnnotation
  
  type RestElement(argument, ?typeAnnotation, ?loc) =
      inherit PatternNode("RestElement", ?loc = loc)
  