src/librustdoc/passes/collect_trait_impls.rs

   1 use super::Pass;
   2 use crate::clean::*;
   3 use crate::core::DocContext;
   4 use crate::fold::DocFolder;
   5
   6 use rustc_data_structures::fx::FxHashSet;
   7 use rustc_hir::def_id::{DefId, LOCAL_CRATE};
   8 use rustc_span::symbol::sym;
   9
  10 pub const COLLECT_TRAIT_IMPLS: Pass = Pass {
  11     name: "collect-trait-impls",
  12     run: collect_trait_impls,
  13     description: "retrieves trait impls for items in the crate",
  14 };
  15
  16 pub fn collect_trait_impls(krate: Crate, cx: &DocContext<'_>) -> Crate {
  17     let mut synth = SyntheticImplCollector::new(cx);
  18     let mut krate = synth.fold_crate(krate);
  19
  20     let prims: FxHashSet<PrimitiveType> = krate.primitives.iter().map(|p| p.1).collect();
  21
  22     let crate_items = {
  23         let mut coll = ItemCollector::new();
  24         krate = coll.fold_crate(krate);
  25         coll.items
  26     };
  27
  28     let mut new_items = Vec::new();
  29
  30     for &cnum in cx.tcx.crates().iter() {
  31         for &did in cx.tcx.all_trait_implementations(cnum).iter() {
  32             inline::build_impl(cx, did, None, &mut new_items);
  33         }
  34     }
  35
  36     // Also try to inline primitive impls from other crates.
  37     let lang_items = cx.tcx.lang_items();
  38     let primitive_impls = [
  39         lang_items.isize_impl(),
  40         lang_items.i8_impl(),
  41         lang_items.i16_impl(),
  42         lang_items.i32_impl(),
  43         lang_items.i64_impl(),
  44         lang_items.i128_impl(),
  45         lang_items.usize_impl(),
  46         lang_items.u8_impl(),
  47         lang_items.u16_impl(),
  48         lang_items.u32_impl(),
  49         lang_items.u64_impl(),
  50         lang_items.u128_impl(),
  51         lang_items.f32_impl(),
  52         lang_items.f64_impl(),
  53         lang_items.f32_runtime_impl(),
  54         lang_items.f64_runtime_impl(),
  55         lang_items.bool_impl(),
  56         lang_items.char_impl(),
  57         lang_items.str_impl(),
  58         lang_items.slice_impl(),
  59         lang_items.slice_u8_impl(),
  60         lang_items.str_alloc_impl(),
  61         lang_items.slice_alloc_impl(),
  62         lang_items.slice_u8_alloc_impl(),
  63         lang_items.const_ptr_impl(),
  64         lang_items.mut_ptr_impl(),
  65         lang_items.const_slice_ptr_impl(),
  66         lang_items.mut_slice_ptr_impl(),
  67     ];
  68
  69     for def_id in primitive_impls.iter().filter_map(|&def_id| def_id) {
  70         if !def_id.is_local() {
  71             inline::build_impl(cx, def_id, None, &mut new_items);
  72
  73             // FIXME(eddyb) is this `doc(hidden)` check needed?
  74             if !cx.tcx.get_attrs(def_id).lists(sym::doc).has_word(sym::hidden) {
  75                 let self_ty = cx.tcx.type_of(def_id);
  76                 let impls = get_auto_trait_and_blanket_impls(cx, self_ty, def_id);
  77                 let mut renderinfo = cx.renderinfo.borrow_mut();
  78
  79                 new_items.extend(impls.filter(|i| renderinfo.inlined.insert(i.def_id)));
  80             }
  81         }
  82     }
  83
  84     let mut cleaner = BadImplStripper { prims, items: crate_items };
  85
  86     // scan through included items ahead of time to splice in Deref targets to the "valid" sets
  87     for it in &new_items {
  88         if let ImplItem(Impl { ref for_, ref trait_, ref items, .. }) = it.inner {
  89             if cleaner.keep_item(for_) && trait_.def_id() == cx.tcx.lang_items().deref_trait() {
  90                 let target = items
  91                     .iter()
  92                     .filter_map(|item| match item.inner {
  93                         TypedefItem(ref t, true) => Some(&t.type_),
  94                         _ => None,
  95                     })
  96                     .next()
  97                     .expect("Deref impl without Target type");
  98
  99                 if let Some(prim) = target.primitive_type() {
 100                     cleaner.prims.insert(prim);
 101                 } else if let Some(did) = target.def_id() {
 102                     cleaner.items.insert(did);
 103                 }
 104             }
 105         }
 106     }
 107
 108     new_items.retain(|it| {
 109         if let ImplItem(Impl { ref for_, ref trait_, ref blanket_impl, .. }) = it.inner {
 110             cleaner.keep_item(for_)
 111                 || trait_.as_ref().map_or(false, |t| cleaner.keep_item(t))
 112                 || blanket_impl.is_some()
 113         } else {
 114             true
 115         }
 116     });
 117
 118     // `tcx.crates()` doesn't include the local crate, and `tcx.all_trait_implementations`
 119     // doesn't work with it anyway, so pull them from the HIR map instead
 120     for &trait_did in cx.tcx.all_traits(LOCAL_CRATE).iter() {
 121         for &impl_node in cx.tcx.hir().trait_impls(trait_did) {
 122             let impl_did = cx.tcx.hir().local_def_id(impl_node);
 123             inline::build_impl(cx, impl_did, None, &mut new_items);
 124         }
 125     }
 126
 127     if let Some(ref mut it) = krate.module {
 128         if let ModuleItem(Module { ref mut items, .. }) = it.inner {
 129             items.extend(synth.impls);
 130             items.extend(new_items);
 131         } else {
 132             panic!("collect-trait-impls can't run");
 133         }
 134     } else {
 135         panic!("collect-trait-impls can't run");
 136     }
 137
 138     krate
 139 }
 140
 141 struct SyntheticImplCollector<'a, 'tcx> {
 142     cx: &'a DocContext<'tcx>,
 143     impls: Vec<Item>,
 144 }
 145
 146 impl<'a, 'tcx> SyntheticImplCollector<'a, 'tcx> {
 147     fn new(cx: &'a DocContext<'tcx>) -> Self {
 148         SyntheticImplCollector { cx, impls: Vec::new() }
 149     }
 150 }
 151
 152 impl<'a, 'tcx> DocFolder for SyntheticImplCollector<'a, 'tcx> {
 153     fn fold_item(&mut self, i: Item) -> Option<Item> {
 154         if i.is_struct() || i.is_enum() || i.is_union() {
 155             // FIXME(eddyb) is this `doc(hidden)` check needed?
 156             if !self.cx.tcx.get_attrs(i.def_id).lists(sym::doc).has_word(sym::hidden) {
 157                 self.impls.extend(get_auto_trait_and_blanket_impls(
 158                     self.cx,
 159                     self.cx.tcx.type_of(i.def_id),
 160                     i.def_id,
 161                 ));
 162             }
 163         }
 164
 165         self.fold_item_recur(i)
 166     }
 167 }
 168
 169 #[derive(Default)]
 170 struct ItemCollector {
 171     items: FxHashSet<DefId>,
 172 }
 173
 174 impl ItemCollector {
 175     fn new() -> Self {
 176         Self::default()
 177     }
 178 }
 179
 180 impl DocFolder for ItemCollector {
 181     fn fold_item(&mut self, i: Item) -> Option<Item> {
 182         self.items.insert(i.def_id);
 183
 184         self.fold_item_recur(i)
 185     }
 186 }
 187
 188 struct BadImplStripper {
 189     prims: FxHashSet<PrimitiveType>,
 190     items: FxHashSet<DefId>,
 191 }
 192
 193 impl BadImplStripper {
 194     fn keep_item(&self, ty: &Type) -> bool {
 195         if let Generic(_) = ty {
 196             // keep impls made on generics
 197             true
 198         } else if let Some(prim) = ty.primitive_type() {
 199             self.prims.contains(&prim)
 200         } else if let Some(did) = ty.def_id() {
 201             self.items.contains(&did)
 202         } else {
 203             false
 204         }
 205     }
 206 }