anchor.diff:  
   /// A default import specifier, e.g., foo in import foo from "mod".
   type ImportDefaultSpecifier(local) =
  -    member _.Local: Identifier = local
  -
       interface ImportSpecifier with
           member _.Print(printer) =
               printer.Print(local)
   
   /// A namespace import specifier, e.g., * as foo in import * as foo from "mod".
   type ImportNamespaceSpecifier(local) =
  -    member _.Local: Identifier = local
  -
       interface ImportSpecifier with
           member _.Print(printer) =
               printer.Print("* as ")
  
positive.code: type EmitExpression(value, args, ?loc) =
      member _.Value: string = value
      member _.Args: Expression array = args
      member _.Loc: SourceLocation option = loc
      interface Expression with
          member _.Print(printer) =
              printer.AddLocation(loc)
  
negative.code:                 printer.Print(" implements ")
                  printer.PrintArray(implements, (fun p x -> p.Print(x)), (fun p -> p.Print(", ")))
              printer.Print(" ")
              printer.Print(body)