anchor.diff:          // Check also cases when null is wrapped to represent a specific type
           | Value Null | Wrapped(Value Null, _) -> true
           | _ -> false
  -
  -    // TODO: Improve Expr printing
  -    override x.ToString() =
  -        match x with
  -        | Value _ -> "Value"
  -        | ObjExpr _ -> "{}"
  -        | Wrapped (e, _) -> sprintf "Wrapped (%O)" e
  -        | Apply (callee, args, kind,_,_) ->
  -            let args = args |> List.map string |> String.concat ", "
  -            match kind with
  -            | ApplyMeth -> sprintf "%O(%s)" callee args
  -            | ApplyGet -> sprintf "%O.%s" callee args
  -            | ApplyCons -> sprintf "new %O(%s)" callee args
  -        | Throw _ -> "Throw"
  -        | IfThenElse (cond,thenExpr,elseExpr,_) ->
  -            sprintf "IF %O THEN %O ELSE %O" cond thenExpr elseExpr
  -        | DebugBreak _ -> "Debugger"
  -        | Set(callee, prop, value, _) ->
  -            let prop = match prop with Some p -> "." + string p | None -> ""
  -            sprintf "%O%s = %O" callee prop value
  -        | VarDeclaration(ident, value, _, _) ->
  -            sprintf "LET %s = %O" ident.Name value
  -        | Sequential (exprs,_) ->
  -            exprs |> List.map string |> String.concat ", " |> sprintf "[%s]"
  -        | Loop _ -> "LOOP (TODO)"
  -        | TryCatch _ -> "TRY-CATCH (TODO)"
  -        | Switch _ ->  "SWITCH (TODO)"
  -        | Quote _ -> "QUOTE (TODO)"
  
positive.code:                 | argTypes -> argsEqual m.ArgumentTypes argTypes)
      static member CreateRootModule fileName =
          Entity (lazy Module, Some fileName, "", lazy [])
  
      override x.ToString() = sprintf "%s %A" x.Name x.Kind
  
  type Declaration =
      | ActionDeclaration of Expr * SourceLocation option
  
negative.code:     /// Finds decorator by full name
      member this.TryGetFullDecorator(fullname) =
          this.Decorators |> List.tryFind (fun x -> x.FullName = fullname)
  
  type ExternalEntity =
      | ImportModule of fullName: string * moduleName: string * isNs: bool
  