Macros don't get expanded when used in item name token position

[vadimcn]

All of the examples below fail to compile with an error similar to the following:
test.rs:1:16: 1:17 error: expected ( but found !
test.rs:1 fn concat_idents!(foo, bar) () {}
^

fn concat_idents!(foo, bar) () {}
trait concat_idents!(foo, bar) {}
mod concat_idents!(foo, bar) {}
let concat_idents!(foo, bar) = 0;

[vadimcn]

Hmm, ok, I see. I failed to grok the following sentence during my first ten readings of the Macro Tutorial: "A macro invocation may take the place of (and therefore expand to) either an expression, an item, or a statement".
Too bad, this makes concat_idents!() way less useful than I thought...

[catamorphism]

I don't think we're planning to extend the macro system in this way, but feel free to make another issue requesting it as an RFC :-)