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                     .find_map(|item| match item.inner {
  93                         TypedefItem(ref t, true) => Some(&t.type_),
  94                         _ => None,
  95                     })
  96                     .expect("Deref impl without Target type");
  97
  98                 if let Some(prim) = target.primitive_type() {
  99                     cleaner.prims.insert(prim);
 100                 } else if let Some(did) = target.def_id() {
 101                     cleaner.items.insert(did);
 102                 }
 103             }
 104         }
 105     }
 106
 107     new_items.retain(|it| {
 108         if let ImplItem(Impl { ref for_, ref trait_, ref blanket_impl, .. }) = it.inner {
 109             cleaner.keep_item(for_)
 110                 || trait_.as_ref().map_or(false, |t| cleaner.keep_item(t))
 111                 || blanket_impl.is_some()
 112         } else {
 113             true
 114         }
 115     });
 116
 117     // `tcx.crates()` doesn't include the local crate, and `tcx.all_trait_implementations`
 118     // doesn't work with it anyway, so pull them from the HIR map instead
 119     for &trait_did in cx.tcx.all_traits(LOCAL_CRATE).iter() {
 120         for &impl_node in cx.tcx.hir().trait_impls(trait_did) {
 121             let impl_did = cx.tcx.hir().local_def_id(impl_node);
 122             inline::build_impl(cx, impl_did.to_def_id(), None, &mut new_items);
 123         }
 124     }
 125
 126     if let Some(ref mut it) = krate.module {
 127         if let ModuleItem(Module { ref mut items, .. }) = it.inner {
 128             items.extend(synth.impls);
 129             items.extend(new_items);
 130         } else {
 131             panic!("collect-trait-impls can't run");
 132         }
 133     } else {
 134         panic!("collect-trait-impls can't run");
 135     }
 136
 137     krate
 138 }
 139
 140 struct SyntheticImplCollector<'a, 'tcx> {
 141     cx: &'a DocContext<'tcx>,
 142     impls: Vec<Item>,
 143 }
 144
 145 impl<'a, 'tcx> SyntheticImplCollector<'a, 'tcx> {
 146     fn new(cx: &'a DocContext<'tcx>) -> Self {
 147         SyntheticImplCollector { cx, impls: Vec::new() }
 148     }
 149 }
 150
 151 impl<'a, 'tcx> DocFolder for SyntheticImplCollector<'a, 'tcx> {
 152     fn fold_item(&mut self, i: Item) -> Option<Item> {
 153         if i.is_struct() || i.is_enum() || i.is_union() {
 154             // FIXME(eddyb) is this `doc(hidden)` check needed?
 155             if !self.cx.tcx.get_attrs(i.def_id).lists(sym::doc).has_word(sym::hidden) {
 156                 self.impls.extend(get_auto_trait_and_blanket_impls(
 157                     self.cx,
 158                     self.cx.tcx.type_of(i.def_id),
 159                     i.def_id,
 160                 ));
 161             }
 162         }
 163
 164         self.fold_item_recur(i)
 165     }
 166 }
 167
 168 #[derive(Default)]
 169 struct ItemCollector {
 170     items: FxHashSet<DefId>,
 171 }
 172
 173 impl ItemCollector {
 174     fn new() -> Self {
 175         Self::default()
 176     }
 177 }
 178
 179 impl DocFolder for ItemCollector {
 180     fn fold_item(&mut self, i: Item) -> Option<Item> {
 181         self.items.insert(i.def_id);
 182
 183         self.fold_item_recur(i)
 184     }
 185 }
 186
 187 struct BadImplStripper {
 188     prims: FxHashSet<PrimitiveType>,
 189     items: FxHashSet<DefId>,
 190 }
 191
 192 impl BadImplStripper {
 193     fn keep_item(&self, ty: &Type) -> bool {
 194         if let Generic(_) = ty {
 195             // keep impls made on generics
 196             true
 197         } else if let Some(prim) = ty.primitive_type() {
 198             self.prims.contains(&prim)
 199         } else if let Some(did) = ty.def_id() {
 200             self.items.contains(&did)
 201         } else {
 202             false
 203         }
 204     }
 205 }