Uninformative error message

[Dirk Laurie <dirk.laurie@...>]

I have a program with many instances of

    error(msg)

where msg is each time some expression.
If this expression evaluates to a non-string,
the error message is merely

    lua: (error object is not a string)

There are obviously plenty of easy workarounds,
but is there some deep reason why the traceback
is omitted?