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use ast;
use attr;
use codemap::Span;
use ext::base::ExtCtxt;
use ext::build::AstBuilder;
use ptr::P;
pub fn expand(cx: &mut ExtCtxt, sp: Span, mi: &ast::MetaItem, it: P<ast::Item>) -> P<ast::Item> {
let (cfg, attr) = match mi.node {
ast::MetaList(_, ref mis) if mis.len() == 2 => (&mis[0], &mis[1]),
_ => {
cx.span_err(sp, "expected `#[cfg_attr(<cfg pattern>, <attr>)]`");
return it;
}
};
let mut out = (*it).clone();
if attr::cfg_matches(&cx.parse_sess.span_diagnostic, cx.cfg.as_slice(), &**cfg) {
out.attrs.push(cx.attribute(attr.span, attr.clone()));
}
P(out)
}