Comment # 13 on bug 196 from Iain Buclaw

(In reply to Johannes Pfau from comment #12)
> Smaller test case:
> ----------------------------------------
> class ThreadError {}
> void foo()
> {
>     __gshared error = new ThreadError();
> }

It took me a while to put two and two together, but the unnamed data would be
created by ClassReferenceExp.  Can certainly give it a proper anonymous name
and unset the readonly flag on it.