Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 273 insertions, 0 deletions

diff --git a/src/librustdoc/passes/collect_trait_impls.rs b/src/librustdoc/passes/collect_trait_impls.rs
new file mode 100644
index 000000000..6b699c790
--- /dev/null
+++ b/src/librustdoc/passes/collect_trait_impls.rs
@@ -0,0 +1,273 @@
+//! Collects trait impls for each item in the crate. For example, if a crate
+//! defines a struct that implements a trait, this pass will note that the
+//! struct implements that trait.
+use super::Pass;
+use crate::clean::*;
+use crate::core::DocContext;
+use crate::formats::cache::Cache;
+use crate::visit::DocVisitor;
+
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_hir::def_id::DefId;
+use rustc_middle::ty::{self, DefIdTree};
+use rustc_span::symbol::sym;
+
+pub(crate) const COLLECT_TRAIT_IMPLS: Pass = Pass {
+    name: "collect-trait-impls",
+    run: collect_trait_impls,
+    description: "retrieves trait impls for items in the crate",
+};
+
+pub(crate) fn collect_trait_impls(mut krate: Crate, cx: &mut DocContext<'_>) -> Crate {
+    let synth_impls = cx.sess().time("collect_synthetic_impls", || {
+        let mut synth = SyntheticImplCollector { cx, impls: Vec::new() };
+        synth.visit_crate(&krate);
+        synth.impls
+    });
+
+    let prims: FxHashSet<PrimitiveType> = krate.primitives.iter().map(|p| p.1).collect();
+
+    let crate_items = {
+        let mut coll = ItemCollector::new();
+        cx.sess().time("collect_items_for_trait_impls", || coll.visit_crate(&krate));
+        coll.items
+    };
+
+    let mut new_items_external = Vec::new();
+    let mut new_items_local = Vec::new();
+
+    // External trait impls.
+    cx.with_all_trait_impls(|cx, all_trait_impls| {
+        let _prof_timer = cx.tcx.sess.prof.generic_activity("build_extern_trait_impls");
+        for &impl_def_id in all_trait_impls.iter().skip_while(|def_id| def_id.is_local()) {
+            inline::build_impl(cx, None, impl_def_id, None, &mut new_items_external);
+        }
+    });
+
+    // Local trait impls.
+    cx.with_all_trait_impls(|cx, all_trait_impls| {
+        let _prof_timer = cx.tcx.sess.prof.generic_activity("build_local_trait_impls");
+        let mut attr_buf = Vec::new();
+        for &impl_def_id in all_trait_impls.iter().take_while(|def_id| def_id.is_local()) {
+            let mut parent = Some(cx.tcx.parent(impl_def_id));
+            while let Some(did) = parent {
+                attr_buf.extend(
+                    cx.tcx
+                        .get_attrs(did, sym::doc)
+                        .filter(|attr| {
+                            if let Some([attr]) = attr.meta_item_list().as_deref() {
+                                attr.has_name(sym::cfg)
+                            } else {
+                                false
+                            }
+                        })
+                        .cloned(),
+                );
+                parent = cx.tcx.opt_parent(did);
+            }
+            inline::build_impl(cx, None, impl_def_id, Some(&attr_buf), &mut new_items_local);
+            attr_buf.clear();
+        }
+    });
+
+    cx.tcx.sess.prof.generic_activity("build_primitive_trait_impls").run(|| {
+        for def_id in PrimitiveType::all_impls(cx.tcx) {
+            // Try to inline primitive impls from other crates.
+            if !def_id.is_local() {
+                inline::build_impl(cx, None, def_id, None, &mut new_items_external);
+            }
+        }
+        for (prim, did) in PrimitiveType::primitive_locations(cx.tcx) {
+            // Do not calculate blanket impl list for docs that are not going to be rendered.
+            // While the `impl` blocks themselves are only in `libcore`, the module with `doc`
+            // attached is directly included in `libstd` as well.
+            let tcx = cx.tcx;
+            if did.is_local() {
+                for def_id in prim.impls(tcx).filter(|def_id| {
+                    // Avoid including impl blocks with filled-in generics.
+                    // https://github.com/rust-lang/rust/issues/94937
+                    //
+                    // FIXME(notriddle): https://github.com/rust-lang/rust/issues/97129
+                    //
+                    // This tactic of using inherent impl blocks for getting
+                    // auto traits and blanket impls is a hack. What we really
+                    // want is to check if `[T]` impls `Send`, which has
+                    // nothing to do with the inherent impl.
+                    //
+                    // Rustdoc currently uses these `impl` block as a source of
+                    // the `Ty`, as well as the `ParamEnv`, `SubstsRef`, and
+                    // `Generics`. To avoid relying on the `impl` block, these
+                    // things would need to be created from wholecloth, in a
+                    // form that is valid for use in type inference.
+                    let ty = tcx.type_of(def_id);
+                    match ty.kind() {
+                        ty::Slice(ty)
+                        | ty::Ref(_, ty, _)
+                        | ty::RawPtr(ty::TypeAndMut { ty, .. }) => {
+                            matches!(ty.kind(), ty::Param(..))
+                        }
+                        ty::Tuple(tys) => tys.iter().all(|ty| matches!(ty.kind(), ty::Param(..))),
+                        _ => true,
+                    }
+                }) {
+                    let impls = get_auto_trait_and_blanket_impls(cx, def_id);
+                    new_items_external.extend(impls.filter(|i| cx.inlined.insert(i.item_id)));
+                }
+            }
+        }
+    });
+
+    let mut cleaner = BadImplStripper { prims, items: crate_items, cache: &cx.cache };
+    let mut type_did_to_deref_target: FxHashMap<DefId, &Type> = FxHashMap::default();
+
+    // Follow all `Deref` targets of included items and recursively add them as valid
+    fn add_deref_target(
+        cx: &DocContext<'_>,
+        map: &FxHashMap<DefId, &Type>,
+        cleaner: &mut BadImplStripper<'_>,
+        targets: &mut FxHashSet<DefId>,
+        type_did: DefId,
+    ) {
+        if let Some(target) = map.get(&type_did) {
+            debug!("add_deref_target: type {:?}, target {:?}", type_did, target);
+            if let Some(target_prim) = target.primitive_type() {
+                cleaner.prims.insert(target_prim);
+            } else if let Some(target_did) = target.def_id(&cx.cache) {
+                // `impl Deref<Target = S> for S`
+                if !targets.insert(target_did) {
+                    // Avoid infinite cycles
+                    return;
+                }
+                cleaner.items.insert(target_did.into());
+                add_deref_target(cx, map, cleaner, targets, target_did);
+            }
+        }
+    }
+
+    // scan through included items ahead of time to splice in Deref targets to the "valid" sets
+    for it in new_items_external.iter().chain(new_items_local.iter()) {
+        if let ImplItem(box Impl { ref for_, ref trait_, ref items, .. }) = *it.kind {
+            if trait_.as_ref().map(|t| t.def_id()) == cx.tcx.lang_items().deref_trait()
+                && cleaner.keep_impl(for_, true)
+            {
+                let target = items
+                    .iter()
+                    .find_map(|item| match *item.kind {
+                        AssocTypeItem(ref t, _) => Some(&t.type_),
+                        _ => None,
+                    })
+                    .expect("Deref impl without Target type");
+
+                if let Some(prim) = target.primitive_type() {
+                    cleaner.prims.insert(prim);
+                } else if let Some(did) = target.def_id(&cx.cache) {
+                    cleaner.items.insert(did.into());
+                }
+                if let Some(for_did) = for_.def_id(&cx.cache) {
+                    if type_did_to_deref_target.insert(for_did, target).is_none() {
+                        // Since only the `DefId` portion of the `Type` instances is known to be same for both the
+                        // `Deref` target type and the impl for type positions, this map of types is keyed by
+                        // `DefId` and for convenience uses a special cleaner that accepts `DefId`s directly.
+                        if cleaner.keep_impl_with_def_id(for_did.into()) {
+                            let mut targets = FxHashSet::default();
+                            targets.insert(for_did);
+                            add_deref_target(
+                                cx,
+                                &type_did_to_deref_target,
+                                &mut cleaner,
+                                &mut targets,
+                                for_did,
+                            );
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    // Filter out external items that are not needed
+    new_items_external.retain(|it| {
+        if let ImplItem(box Impl { ref for_, ref trait_, ref kind, .. }) = *it.kind {
+            cleaner.keep_impl(
+                for_,
+                trait_.as_ref().map(|t| t.def_id()) == cx.tcx.lang_items().deref_trait(),
+            ) || trait_.as_ref().map_or(false, |t| cleaner.keep_impl_with_def_id(t.def_id().into()))
+                || kind.is_blanket()
+        } else {
+            true
+        }
+    });
+
+    if let ModuleItem(Module { items, .. }) = &mut *krate.module.kind {
+        items.extend(synth_impls);
+        items.extend(new_items_external);
+        items.extend(new_items_local);
+    } else {
+        panic!("collect-trait-impls can't run");
+    };
+
+    krate
+}
+
+struct SyntheticImplCollector<'a, 'tcx> {
+    cx: &'a mut DocContext<'tcx>,
+    impls: Vec<Item>,
+}
+
+impl<'a, 'tcx> DocVisitor for SyntheticImplCollector<'a, 'tcx> {
+    fn visit_item(&mut self, i: &Item) {
+        if i.is_struct() || i.is_enum() || i.is_union() {
+            // FIXME(eddyb) is this `doc(hidden)` check needed?
+            if !self.cx.tcx.is_doc_hidden(i.item_id.expect_def_id()) {
+                self.impls
+                    .extend(get_auto_trait_and_blanket_impls(self.cx, i.item_id.expect_def_id()));
+            }
+        }
+
+        self.visit_item_recur(i)
+    }
+}
+
+#[derive(Default)]
+struct ItemCollector {
+    items: FxHashSet<ItemId>,
+}
+
+impl ItemCollector {
+    fn new() -> Self {
+        Self::default()
+    }
+}
+
+impl DocVisitor for ItemCollector {
+    fn visit_item(&mut self, i: &Item) {
+        self.items.insert(i.item_id);
+
+        self.visit_item_recur(i)
+    }
+}
+
+struct BadImplStripper<'a> {
+    prims: FxHashSet<PrimitiveType>,
+    items: FxHashSet<ItemId>,
+    cache: &'a Cache,
+}
+
+impl<'a> BadImplStripper<'a> {
+    fn keep_impl(&self, ty: &Type, is_deref: bool) -> bool {
+        if let Generic(_) = ty {
+            // keep impls made on generics
+            true
+        } else if let Some(prim) = ty.primitive_type() {
+            self.prims.contains(&prim)
+        } else if let Some(did) = ty.def_id(self.cache) {
+            is_deref || self.keep_impl_with_def_id(did.into())
+        } else {
+            false
+        }
+    }
+
+    fn keep_impl_with_def_id(&self, item_id: ItemId) -> bool {
+        self.items.contains(&item_id)
+    }
+}