3 use crate::clean::cfg::Cfg;
4 use crate::clean::{Crate, Item};
5 use crate::core::DocContext;
6 use crate::fold::DocFolder;
7 use crate::passes::Pass;
9 pub const PROPAGATE_DOC_CFG: Pass = Pass {
10 name: "propagate-doc-cfg",
11 run: propagate_doc_cfg,
12 description: "propagates `#[doc(cfg(...))]` to child items",
15 pub fn propagate_doc_cfg(cr: Crate, _: &DocContext<'_>) -> Crate {
16 CfgPropagator { parent_cfg: None }.fold_crate(cr)
19 struct CfgPropagator {
20 parent_cfg: Option<Arc<Cfg>>,
23 impl DocFolder for CfgPropagator {
24 fn fold_item(&mut self, mut item: Item) -> Option<Item> {
25 let old_parent_cfg = self.parent_cfg.clone();
27 let new_cfg = match (self.parent_cfg.take(), item.attrs.cfg.take()) {
29 (Some(rc), None) | (None, Some(rc)) => Some(rc),
30 (Some(mut a), Some(b)) => {
31 let b = Arc::try_unwrap(b).unwrap_or_else(|rc| Cfg::clone(&rc));
32 *Arc::make_mut(&mut a) &= b;
36 self.parent_cfg = new_cfg.clone();
37 item.attrs.cfg = new_cfg;
39 let result = self.fold_item_recur(item);
40 self.parent_cfg = old_parent_cfg;