rustdoc: Replace `FakeDefId` with new `ItemId` type

src/librustdoc/clean/auto_trait.rs

@@ -113,7 +113,7 @@ fn generate_for_trait(
             name: None,
             attrs: Default::default(),
             visibility: Inherited,
-            def_id: FakeDefId::new_fake(item_def_id.krate),
+            def_id: ItemId::Auto { trait_: trait_def_id, for_: item_def_id },
             kind: box ImplItem(Impl {
                 span: Span::dummy(),
                 unsafety: hir::Unsafety::Normal,

src/librustdoc/clean/blanket_impl.rs

@@ -96,7 +96,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                     name: None,
                     attrs: Default::default(),
                     visibility: Inherited,
-                    def_id: FakeDefId::new_fake(item_def_id.krate),
+                    def_id: ItemId::Blanket { trait_: trait_def_id, for_: item_def_id },
                     kind: box ImplItem(Impl {
                         span: self.cx.tcx.def_span(impl_def_id).clean(self.cx),
                         unsafety: hir::Unsafety::Normal,

src/librustdoc/clean/inline.rs

@@ -15,7 +15,7 @@
 use rustc_span::symbol::{kw, sym, Symbol};
 
 use crate::clean::{
-    self, utils, Attributes, AttributesExt, FakeDefId, GetDefId, NestedAttributesExt, Type,
+    self, utils, Attributes, AttributesExt, GetDefId, ItemId, NestedAttributesExt, Type,
 };
 use crate::core::DocContext;
 use crate::formats::item_type::ItemType;
@@ -486,7 +486,7 @@ fn build_module(
                 items.push(clean::Item {
                     name: None,
                     attrs: box clean::Attributes::default(),
-                    def_id: FakeDefId::new_fake(did.krate),
+                    def_id: ItemId::Primitive(did.krate),
                     visibility: clean::Public,
                     kind: box clean::ImportItem(clean::Import::new_simple(
                         item.ident.name,

src/librustdoc/clean/types.rs

-use std::cell::{Cell, RefCell};
+use std::cell::RefCell;
 use std::default::Default;
 use std::hash::{Hash, Hasher};
 use std::iter::FromIterator;
@@ -18,7 +18,7 @@
 use rustc_data_structures::thin_vec::ThinVec;
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind, Res};
-use rustc_hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX, LOCAL_CRATE};
+use rustc_hir::def_id::{CrateNum, DefId, DefIndex, CRATE_DEF_INDEX};
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::{BodyId, Mutability};
 use rustc_index::vec::IndexVec;
@@ -48,73 +48,68 @@
 use self::SelfTy::*;
 use self::Type::*;
 
-crate type FakeDefIdSet = FxHashSet<FakeDefId>;
+crate type ItemIdSet = FxHashSet<ItemId>;
 
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Copy)]
-crate enum FakeDefId {
-    Real(DefId),
-    Fake(DefIndex, CrateNum),
-}
-
-impl FakeDefId {
-    #[cfg(parallel_compiler)]
-    crate fn new_fake(crate: CrateNum) -> Self {
-        unimplemented!("")
-    }
-
-    #[cfg(not(parallel_compiler))]
-    crate fn new_fake(krate: CrateNum) -> Self {
-        thread_local!(static FAKE_DEF_ID_COUNTER: Cell<usize> = Cell::new(0));
-        let id = FAKE_DEF_ID_COUNTER.with(|id| {
-            let tmp = id.get();
-            id.set(tmp + 1);
-            tmp
-        });
-        Self::Fake(DefIndex::from(id), krate)
-    }
-
+crate enum ItemId {
+    /// A "normal" item that uses a [`DefId`] for identification.
+    DefId(DefId),
+    /// Identifier that is used for auto traits.
+    Auto { trait_: DefId, for_: DefId },
+    /// Identifier that is used for blanket implementations.
+    Blanket { trait_: DefId, for_: DefId },
+    /// Identifier for primitive types.
+    Primitive(CrateNum),
+}
+
+impl ItemId {
     #[inline]
     crate fn is_local(self) -> bool {
         match self {
-            FakeDefId::Real(id) => id.is_local(),
-            FakeDefId::Fake(_, krate) => krate == LOCAL_CRATE,
+            ItemId::DefId(id) => id.is_local(),
+            _ => false,
         }
     }
 
     #[inline]
     #[track_caller]
     crate fn expect_real(self) -> rustc_hir::def_id::DefId {
-        self.as_real().unwrap_or_else(|| panic!("FakeDefId::expect_real: `{:?}` isn't real", self))
+        self.as_real()
+            .unwrap_or_else(|| panic!("ItemId::expect_real: `{:?}` isn't a real ItemId", self))
     }
 
     #[inline]
     crate fn as_real(self) -> Option<DefId> {
         match self {
-            FakeDefId::Real(id) => Some(id),
-            FakeDefId::Fake(_, _) => None,
+            ItemId::DefId(id) => Some(id),
+            _ => None,
         }
     }
 
     #[inline]
     crate fn krate(self) -> CrateNum {
         match self {
-            FakeDefId::Real(id) => id.krate,
-            FakeDefId::Fake(_, krate) => krate,
+            ItemId::DefId(id) => id.krate,
+            ItemId::Auto { trait_, .. } => trait_.krate,
+            ItemId::Blanket { trait_, .. } => trait_.krate,
+            ItemId::Primitive(krate) => krate,
         }
     }
 
     #[inline]
     crate fn index(self) -> Option<DefIndex> {
         match self {
-            FakeDefId::Real(id) => Some(id.index),
-            FakeDefId::Fake(_, _) => None,
+            ItemId::DefId(id) => Some(id.index),
+            ItemId::Auto { trait_, .. } => Some(trait_.index),
+            ItemId::Blanket { trait_, .. } => Some(trait_.index),
+            ItemId::Primitive(..) => None,
         }
     }
 }
 
-impl From<DefId> for FakeDefId {
+impl From<DefId> for ItemId {
     fn from(id: DefId) -> Self {
-        Self::Real(id)
+        Self::DefId(id)
     }
 }
 
@@ -338,14 +333,14 @@ fn to_remote(url: impl ToString) -> ExternalLocation {
     /// Information about this item that is specific to what kind of item it is.
     /// E.g., struct vs enum vs function.
     crate kind: Box<ItemKind>,
-    crate def_id: FakeDefId,
+    crate def_id: ItemId,
 
     crate cfg: Option<Arc<Cfg>>,
 }
 
 // `Item` is used a lot. Make sure it doesn't unintentionally get bigger.
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
-rustc_data_structures::static_assert_size!(Item, 48);
+rustc_data_structures::static_assert_size!(Item, 56);
 
 crate fn rustc_span(def_id: DefId, tcx: TyCtxt<'_>) -> Span {
     Span::from_rustc_span(def_id.as_local().map_or_else(
@@ -664,7 +659,8 @@ pub fn from_def_id_and_attrs_and_parts(
     }
 
     crate fn is_fake(&self) -> bool {
-        matches!(self.def_id, FakeDefId::Fake(_, _))
+        // FIXME: Find a better way to handle this
+        !matches!(self.def_id, ItemId::DefId(..))
     }
 }
 

src/librustdoc/core.rs

@@ -30,7 +30,7 @@
 use std::rc::Rc;
 
 use crate::clean::inline::build_external_trait;
-use crate::clean::{self, FakeDefId, TraitWithExtraInfo};
+use crate::clean::{self, ItemId, TraitWithExtraInfo};
 use crate::config::{Options as RustdocOptions, OutputFormat, RenderOptions};
 use crate::formats::cache::Cache;
 use crate::passes::{self, Condition::*, ConditionalPass};
@@ -78,7 +78,7 @@
     /// This same cache is used throughout rustdoc, including in [`crate::html::render`].
     crate cache: Cache,
     /// Used by [`clean::inline`] to tell if an item has already been inlined.
-    crate inlined: FxHashSet<FakeDefId>,
+    crate inlined: FxHashSet<ItemId>,
     /// Used by `calculate_doc_coverage`.
     crate output_format: OutputFormat,
 }
@@ -128,12 +128,13 @@ impl<'tcx> DocContext<'tcx> {
 
     /// Like `hir().local_def_id_to_hir_id()`, but skips calling it on fake DefIds.
     /// (This avoids a slice-index-out-of-bounds panic.)
-    crate fn as_local_hir_id(tcx: TyCtxt<'_>, def_id: FakeDefId) -> Option<HirId> {
+    crate fn as_local_hir_id(tcx: TyCtxt<'_>, def_id: ItemId) -> Option<HirId> {
         match def_id {
-            FakeDefId::Real(real_id) => {
+            ItemId::DefId(real_id) => {
                 real_id.as_local().map(|def_id| tcx.hir().local_def_id_to_hir_id(def_id))
             }
-            FakeDefId::Fake(_, _) => None,
+            // FIXME: Can this be `Some` for `Auto` or `Blanket`?
+            _ => None,
         }
     }
 }

src/librustdoc/formats/cache.rs

@@ -8,7 +8,7 @@
 use rustc_middle::ty::TyCtxt;
 use rustc_span::symbol::sym;
 
-use crate::clean::{self, FakeDefId, GetDefId};
+use crate::clean::{self, GetDefId, ItemId};
 use crate::fold::DocFolder;
 use crate::formats::item_type::ItemType;
 use crate::formats::Impl;
@@ -122,7 +122,7 @@
     /// All intra-doc links resolved so far.
     ///
     /// Links are indexed by the DefId of the item they document.
-    crate intra_doc_links: BTreeMap<FakeDefId, Vec<clean::ItemLink>>,
+    crate intra_doc_links: BTreeMap<ItemId, Vec<clean::ItemLink>>,
 }
 
 /// This struct is used to wrap the `cache` and `tcx` in order to run `DocFolder`.

src/librustdoc/html/format.rs

@@ -19,7 +19,7 @@
 use rustc_target::spec::abi::Abi;
 
 use crate::clean::{
-    self, utils::find_nearest_parent_module, ExternalCrate, FakeDefId, GetDefId, PrimitiveType,
+    self, utils::find_nearest_parent_module, ExternalCrate, GetDefId, ItemId, PrimitiveType,
 };
 use crate::formats::item_type::ItemType;
 use crate::html::escape::Escape;
@@ -1181,7 +1181,7 @@ fn inner_full_print(
 impl clean::Visibility {
     crate fn print_with_space<'a, 'tcx: 'a>(
         self,
-        item_did: FakeDefId,
+        item_did: ItemId,
         cx: &'a Context<'tcx>,
     ) -> impl fmt::Display + 'a + Captures<'tcx> {
         let to_print = match self {

src/librustdoc/html/render/mod.rs

@@ -53,7 +53,7 @@
 use serde::ser::SerializeSeq;
 use serde::{Serialize, Serializer};
 
-use crate::clean::{self, FakeDefId, GetDefId, RenderedLink, SelfTy};
+use crate::clean::{self, GetDefId, ItemId, RenderedLink, SelfTy};
 use crate::docfs::PathError;
 use crate::error::Error;
 use crate::formats::cache::Cache;
@@ -987,7 +987,7 @@ fn render_attributes_in_code(w: &mut Buffer, it: &clean::Item) {
 #[derive(Copy, Clone)]
 enum AssocItemLink<'a> {
     Anchor(Option<&'a str>),
-    GotoSource(FakeDefId, &'a FxHashSet<Symbol>),
+    GotoSource(ItemId, &'a FxHashSet<Symbol>),
 }
 
 impl<'a> AssocItemLink<'a> {

src/librustdoc/json/conversions.rs

@@ -15,7 +15,7 @@
 use rustdoc_json_types::*;
 
 use crate::clean::utils::print_const_expr;
-use crate::clean::{self, FakeDefId};
+use crate::clean::{self, ItemId};
 use crate::formats::item_type::ItemType;
 use crate::json::JsonRenderer;
 use std::collections::HashSet;
@@ -30,7 +30,7 @@ pub(super) fn convert_item(&self, item: clean::Item) -> Option<Item> {
             .into_iter()
             .flatten()
             .filter_map(|clean::ItemLink { link, did, .. }| {
-                did.map(|did| (link.clone(), from_def_id(did.into())))
+                did.map(|did| (link.clone(), from_item_id(did.into())))
             })
             .collect();
         let docs = item.attrs.collapsed_doc_value();
@@ -47,7 +47,7 @@ pub(super) fn convert_item(&self, item: clean::Item) -> Option<Item> {
             _ => from_clean_item(item, self.tcx),
         };
         Some(Item {
-            id: from_def_id(def_id),
+            id: from_item_id(def_id),
             crate_id: def_id.krate().as_u32(),
             name: name.map(|sym| sym.to_string()),
             span: self.convert_span(span),
@@ -86,7 +86,7 @@ fn convert_visibility(&self, v: clean::Visibility) -> Visibility {
             Inherited => Visibility::Default,
             Restricted(did) if did.index == CRATE_DEF_INDEX => Visibility::Crate,
             Restricted(did) => Visibility::Restricted {
-                parent: from_def_id(did.into()),
+                parent: from_item_id(did.into()),
                 path: self.tcx.def_path(did).to_string_no_crate_verbose(),
             },
         }
@@ -170,12 +170,10 @@ fn from_tcx(kind: clean::TypeBindingKind, tcx: TyCtxt<'_>) -> Self {
     }
 }
 
-crate fn from_def_id(did: FakeDefId) -> Id {
+crate fn from_item_id(did: ItemId) -> Id {
     match did {
-        FakeDefId::Real(did) => Id(format!("{}:{}", did.krate.as_u32(), u32::from(did.index))),
-        // We need to differentiate real and fake ids, because the indices might overlap for fake
-        // and real DefId's, which would cause two different Id's treated as they were the same.
-        FakeDefId::Fake(idx, krate) => Id(format!("F{}:{}", krate.as_u32(), u32::from(idx))),
+        ItemId::DefId(did) => Id(format!("{}:{}", did.krate.as_u32(), u32::from(did.index))),
+        _ => todo!("how should json ItemId's be represented?"),
     }
 }
 
@@ -375,7 +373,7 @@ fn from_tcx(ty: clean::Type, tcx: TyCtxt<'_>) -> Self {
         match ty {
             ResolvedPath { path, did, is_generic: _ } => Type::ResolvedPath {
                 name: path.whole_name(),
-                id: from_def_id(did.into()),
+                id: from_item_id(did.into()),
                 args: path.segments.last().map(|args| Box::new(args.clone().args.into_tcx(tcx))),
                 param_names: Vec::new(),
             },
@@ -387,7 +385,7 @@ fn from_tcx(ty: clean::Type, tcx: TyCtxt<'_>) -> Self {
 
                 Type::ResolvedPath {
                     name: path.whole_name(),
-                    id: from_def_id(id.into()),
+                    id: from_item_id(id.into()),
                     args: path
                         .segments
                         .last()
@@ -568,13 +566,13 @@ fn from_tcx(import: clean::Import, _tcx: TyCtxt<'_>) -> Self {
             Simple(s) => Import {
                 source: import.source.path.whole_name(),
                 name: s.to_string(),
-                id: import.source.did.map(FakeDefId::from).map(from_def_id),
+                id: import.source.did.map(ItemId::from).map(from_item_id),
                 glob: false,
             },
             Glob => Import {
                 source: import.source.path.whole_name(),
                 name: import.source.path.last_name().to_string(),
-                id: import.source.did.map(FakeDefId::from).map(from_def_id),
+                id: import.source.did.map(ItemId::from).map(from_item_id),
                 glob: true,
             },
         }
@@ -668,5 +666,5 @@ fn from_tcx(kind: ItemType, _tcx: TyCtxt<'_>) -> Self {
 }
 
 fn ids(items: impl IntoIterator<Item = clean::Item>) -> Vec<Id> {
-    items.into_iter().filter(|x| !x.is_stripped()).map(|i| from_def_id(i.def_id)).collect()
+    items.into_iter().filter(|x| !x.is_stripped()).map(|i| from_item_id(i.def_id)).collect()
 }

src/librustdoc/json/mod.rs

@@ -25,7 +25,7 @@
 use crate::formats::cache::Cache;
 use crate::formats::FormatRenderer;
 use crate::html::render::cache::ExternalLocation;
-use crate::json::conversions::{from_def_id, IntoWithTcx};
+use crate::json::conversions::{from_item_id, IntoWithTcx};
 
 #[derive(Clone)]
 crate struct JsonRenderer<'tcx> {
@@ -53,7 +53,7 @@ fn get_trait_implementors(&mut self, id: DefId) -> Vec<types::Id> {
                     .map(|i| {
                         let item = &i.impl_item;
                         self.item(item.clone()).unwrap();
-                        from_def_id(item.def_id)
+                        from_item_id(item.def_id)
                     })
                     .collect()
             })
@@ -71,7 +71,7 @@ fn get_impls(&mut self, id: DefId) -> Vec<types::Id> {
                         let item = &i.impl_item;
                         if item.def_id.is_local() {
                             self.item(item.clone()).unwrap();
-                            Some(from_def_id(item.def_id))
+                            Some(from_item_id(item.def_id))
                         } else {
                             None
                         }
@@ -91,9 +91,9 @@ fn get_trait_items(&mut self) -> Vec<(types::Id, types::Item)> {
                     let trait_item = &trait_item.trait_;
                     trait_item.items.clone().into_iter().for_each(|i| self.item(i).unwrap());
                     Some((
-                        from_def_id(id.into()),
+                        from_item_id(id.into()),
                         types::Item {
-                            id: from_def_id(id.into()),
+                            id: from_item_id(id.into()),
                             crate_id: id.krate.as_u32(),
                             name: self
                                 .cache
@@ -170,7 +170,7 @@ fn item(&mut self, item: clean::Item) -> Result<(), Error> {
             } else if let types::ItemEnum::Enum(ref mut e) = new_item.inner {
                 e.impls = self.get_impls(id.expect_real())
             }
-            let removed = self.index.borrow_mut().insert(from_def_id(id), new_item.clone());
+            let removed = self.index.borrow_mut().insert(from_item_id(id), new_item.clone());
 
             // FIXME(adotinthevoid): Currently, the index is duplicated. This is a sanity check
             // to make sure the items are unique. The main place this happens is when an item, is
@@ -207,7 +207,7 @@ fn after_krate(&mut self) -> Result<(), Error> {
                 .chain(self.cache.external_paths.clone().into_iter())
                 .map(|(k, (path, kind))| {
                     (
-                        from_def_id(k.into()),
+                        from_item_id(k.into()),
                         types::ItemSummary {
                             crate_id: k.krate.as_u32(),
                             path,

src/librustdoc/passes/collect_trait_impls.rs

@@ -149,7 +149,7 @@ fn fold_item(&mut self, i: Item) -> Option<Item> {
 
 #[derive(Default)]
 struct ItemCollector {
-    items: FxHashSet<FakeDefId>,
+    items: FxHashSet<ItemId>,
 }
 
 impl ItemCollector {
@@ -168,7 +168,7 @@ fn fold_item(&mut self, i: Item) -> Option<Item> {
 
 struct BadImplStripper {
     prims: FxHashSet<PrimitiveType>,
-    items: FxHashSet<FakeDefId>,
+    items: FxHashSet<ItemId>,
 }
 
 impl BadImplStripper {
@@ -185,7 +185,7 @@ fn keep_impl(&self, ty: &Type) -> bool {
         }
     }
 
-    fn keep_impl_with_def_id(&self, did: FakeDefId) -> bool {
+    fn keep_impl_with_def_id(&self, did: ItemId) -> bool {
         self.items.contains(&did)
     }
 }

src/librustdoc/passes/strip_hidden.rs

@@ -2,7 +2,7 @@
 use std::mem;
 
 use crate::clean;
-use crate::clean::{FakeDefIdSet, Item, NestedAttributesExt};
+use crate::clean::{Item, ItemIdSet, NestedAttributesExt};
 use crate::core::DocContext;
 use crate::fold::{strip_item, DocFolder};
 use crate::passes::{ImplStripper, Pass};
@@ -15,7 +15,7 @@
 
 /// Strip items marked `#[doc(hidden)]`
 crate fn strip_hidden(krate: clean::Crate, _: &mut DocContext<'_>) -> clean::Crate {
-    let mut retained = FakeDefIdSet::default();
+    let mut retained = ItemIdSet::default();
 
     // strip all #[doc(hidden)] items
     let krate = {
@@ -29,7 +29,7 @@
 }
 
 struct Stripper<'a> {
-    retained: &'a mut FakeDefIdSet,
+    retained: &'a mut ItemIdSet,
     update_retained: bool,
 }
 

src/librustdoc/passes/strip_private.rs

-use crate::clean::{self, FakeDefIdSet};
+use crate::clean::{self, ItemIdSet};
 use crate::core::DocContext;
 use crate::fold::DocFolder;
 use crate::passes::{ImplStripper, ImportStripper, Pass, Stripper};
@@ -14,7 +14,7 @@
 /// crate, specified by the `xcrate` flag.
 crate fn strip_private(mut krate: clean::Crate, cx: &mut DocContext<'_>) -> clean::Crate {
     // This stripper collects all *retained* nodes.
-    let mut retained = FakeDefIdSet::default();
+    let mut retained = ItemIdSet::default();
 
     // strip all private items
     {

src/librustdoc/passes/stripper.rs

@@ -2,11 +2,11 @@
 use rustc_middle::middle::privacy::AccessLevels;
 use std::mem;
 
-use crate::clean::{self, FakeDefIdSet, GetDefId, Item};
+use crate::clean::{self, GetDefId, Item, ItemIdSet};
 use crate::fold::{strip_item, DocFolder};
 
 crate struct Stripper<'a> {
-    crate retained: &'a mut FakeDefIdSet,
+    crate retained: &'a mut ItemIdSet,
     crate access_levels: &'a AccessLevels<DefId>,
     crate update_retained: bool,
 }
@@ -116,7 +116,7 @@ fn fold_item(&mut self, i: Item) -> Option<Item> {
 
 /// This stripper discards all impls which reference stripped items
 crate struct ImplStripper<'a> {
-    crate retained: &'a FakeDefIdSet,
+    crate retained: &'a ItemIdSet,
 }
 
 impl<'a> DocFolder for ImplStripper<'a> {