Revert "rustdoc: factor all-impls-for-item out into its own method"

This reverts commit c3e5ad448b87be31e570c048cf7ba3b1e7daec44.

3 files changed, 78 insertions, 55 deletions

diff --git a/src/librustdoc/html/render/context.rs b/src/librustdoc/html/render/context.rs
index 7e432ecedc5..6da9e45a1da 100644
--- a/src/librustdoc/html/render/context.rs
+++ b/src/librustdoc/html/render/context.rs
@@ -7,10 +7,8 @@ use std::sync::mpsc::{channel, Receiver};
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_hir::def_id::{DefIdMap, LOCAL_CRATE};
-use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
-use rustc_span::def_id::DefId;
 use rustc_span::edition::Edition;
 use rustc_span::source_map::FileName;
 use rustc_span::{sym, Symbol};
@@ -25,13 +23,13 @@ use super::{
     AllTypes, LinkFromSrc, StylePath,
 };
 use crate::clean::utils::has_doc_flag;
-use crate::clean::{self, types::ExternalLocation, ExternalCrate, TypeAliasItem};
+use crate::clean::{self, types::ExternalLocation, ExternalCrate};
 use crate::config::{ModuleSorting, RenderOptions};
 use crate::docfs::{DocFS, PathError};
 use crate::error::Error;
 use crate::formats::cache::Cache;
 use crate::formats::item_type::ItemType;
-use crate::formats::{self, FormatRenderer};
+use crate::formats::FormatRenderer;
 use crate::html::escape::Escape;
 use crate::html::format::{join_with_double_colon, Buffer};
 use crate::html::markdown::{self, plain_text_summary, ErrorCodes, IdMap};
@@ -150,47 +148,6 @@ impl SharedContext<'_> {
     pub(crate) fn edition(&self) -> Edition {
         self.tcx.sess.edition()
     }
-
-    /// Returns a list of impls on the given type, and, if it's a type alias,
-    /// other types that it aliases.
-    pub(crate) fn all_impls_for_item<'a>(
-        &'a self,
-        it: &clean::Item,
-        did: DefId,
-    ) -> Vec<&'a formats::Impl> {
-        let tcx = self.tcx;
-        let cache = &self.cache;
-        let mut v: Vec<&formats::Impl> =
-            cache.impls.get(&did).map(Vec::as_slice).unwrap_or(&[]).iter().collect();
-        if let TypeAliasItem(ait) = &*it.kind &&
-            let aliased_clean_type = ait.item_type.as_ref().unwrap_or(&ait.type_) &&
-            let Some(aliased_type_defid) = aliased_clean_type.def_id(cache) &&
-            let Some(av) = cache.impls.get(&aliased_type_defid) &&
-            let Some(alias_def_id) = it.item_id.as_def_id()
-        {
-            // This branch of the compiler compares types structually, but does
-            // not check trait bounds. That's probably fine, since type aliases
-            // don't normally constrain on them anyway.
-            // https://github.com/rust-lang/rust/issues/21903
-            //
-            // FIXME(lazy_type_alias): Once the feature is complete or stable, rewrite this to use type unification.
-            // Be aware of `tests/rustdoc/issue-112515-impl-ty-alias.rs` which might regress.
-            let aliased_ty = tcx.type_of(alias_def_id).skip_binder();
-            let reject_cx = DeepRejectCtxt {
-                treat_obligation_params: TreatParams::AsCandidateKey,
-            };
-            v.extend(av.iter().filter(|impl_| {
-                if let Some(impl_def_id) = impl_.impl_item.item_id.as_def_id() {
-                    reject_cx.types_may_unify(aliased_ty, tcx.type_of(impl_def_id).skip_binder())
-                } else {
-                    false
-                }
-            }));
-        }
-        let mut saw_impls = FxHashSet::default();
-        v.retain(|i| saw_impls.insert(i.def_id()));
-        v
-    }
 }
 
 impl<'tcx> Context<'tcx> {
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 89e29d8b59b..515dedbb85f 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -55,6 +55,7 @@ use rustc_hir::def_id::{DefId, DefIdSet};
 use rustc_hir::Mutability;
 use rustc_middle::middle::stability;
 use rustc_middle::ty::{self, TyCtxt};
+use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
 use rustc_span::{
     symbol::{sym, Symbol},
     BytePos, FileName, RealFileName,
@@ -62,6 +63,7 @@ use rustc_span::{
 use serde::ser::{SerializeMap, SerializeSeq};
 use serde::{Serialize, Serializer};
 
+use crate::clean::types::TypeAliasItem;
 use crate::clean::{self, ItemId, RenderedLink, SelfTy};
 use crate::error::Error;
 use crate::formats::cache::Cache;
@@ -1132,13 +1134,13 @@ pub(crate) fn render_all_impls(
 fn render_assoc_items<'a, 'cx: 'a>(
     cx: &'a mut Context<'cx>,
     containing_item: &'a clean::Item,
-    did: DefId,
+    it: DefId,
     what: AssocItemRender<'a>,
 ) -> impl fmt::Display + 'a + Captures<'cx> {
     let mut derefs = DefIdSet::default();
-    derefs.insert(did);
+    derefs.insert(it);
     display_fn(move |f| {
-        render_assoc_items_inner(f, cx, containing_item, did, what, &mut derefs);
+        render_assoc_items_inner(f, cx, containing_item, it, what, &mut derefs);
         Ok(())
     })
 }
@@ -1147,16 +1149,46 @@ fn render_assoc_items_inner(
     mut w: &mut dyn fmt::Write,
     cx: &mut Context<'_>,
     containing_item: &clean::Item,
-    did: DefId,
+    it: DefId,
     what: AssocItemRender<'_>,
     derefs: &mut DefIdSet,
 ) {
     info!("Documenting associated items of {:?}", containing_item.name);
     let shared = Rc::clone(&cx.shared);
-    let v = shared.all_impls_for_item(containing_item, did);
-    let v = v.as_slice();
-    let (non_trait, traits): (Vec<&Impl>, _) =
-        v.iter().partition(|i| i.inner_impl().trait_.is_none());
+    let cache = &shared.cache;
+    let tcx = cx.tcx();
+    let av = if let TypeAliasItem(ait) = &*containing_item.kind &&
+        let aliased_clean_type = ait.item_type.as_ref().unwrap_or(&ait.type_) &&
+        let Some(aliased_type_defid) = aliased_clean_type.def_id(cache) &&
+        let Some(mut av) = cache.impls.get(&aliased_type_defid).cloned() &&
+        let Some(alias_def_id) = containing_item.item_id.as_def_id()
+    {
+        // This branch of the compiler compares types structually, but does
+        // not check trait bounds. That's probably fine, since type aliases
+        // don't normally constrain on them anyway.
+        // https://github.com/rust-lang/rust/issues/21903
+        //
+        // FIXME(lazy_type_alias): Once the feature is complete or stable, rewrite this to use type unification.
+        // Be aware of `tests/rustdoc/issue-112515-impl-ty-alias.rs` which might regress.
+        let aliased_ty = tcx.type_of(alias_def_id).skip_binder();
+        let reject_cx = DeepRejectCtxt {
+            treat_obligation_params: TreatParams::AsCandidateKey,
+        };
+        av.retain(|impl_| {
+            if let Some(impl_def_id) = impl_.impl_item.item_id.as_def_id() {
+                reject_cx.types_may_unify(aliased_ty, tcx.type_of(impl_def_id).skip_binder())
+            } else {
+                false
+            }
+        });
+        av
+    } else {
+        Vec::new()
+    };
+    let blank = Vec::new();
+    let v = cache.impls.get(&it).unwrap_or(&blank);
+    let (non_trait, traits): (Vec<_>, _) =
+        v.iter().chain(&av[..]).partition(|i| i.inner_impl().trait_.is_none());
     let mut saw_impls = FxHashSet::default();
     if !non_trait.is_empty() {
         let mut tmp_buf = Buffer::html();
diff --git a/src/librustdoc/html/render/sidebar.rs b/src/librustdoc/html/render/sidebar.rs
index fb429f237e3..8ff95477dd8 100644
--- a/src/librustdoc/html/render/sidebar.rs
+++ b/src/librustdoc/html/render/sidebar.rs
@@ -3,10 +3,12 @@ use std::{borrow::Cow, rc::Rc};
 use askama::Template;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::{def::CtorKind, def_id::DefIdSet};
+use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
 use rustc_middle::ty::{self, TyCtxt};
 
 use crate::{
     clean,
+    clean::types::TypeAliasItem,
     formats::{item_type::ItemType, Impl},
     html::{format::Buffer, markdown::IdMap},
 };
@@ -287,8 +289,40 @@ fn sidebar_assoc_items<'a>(
     links: &mut Vec<LinkBlock<'a>>,
 ) {
     let did = it.item_id.expect_def_id();
-    let v = cx.shared.all_impls_for_item(it, it.item_id.expect_def_id());
-    let v = v.as_slice();
+    let cache = cx.cache();
+    let tcx = cx.tcx();
+    let mut v: Vec<&Impl> =
+        cache.impls.get(&did).map(Vec::as_slice).unwrap_or(&[]).iter().collect();
+    if let TypeAliasItem(ait) = &*it.kind &&
+        let aliased_clean_type = ait.item_type.as_ref().unwrap_or(&ait.type_) &&
+        let Some(aliased_type_defid) = aliased_clean_type.def_id(cache) &&
+        let Some(av) = cache.impls.get(&aliased_type_defid) &&
+        let Some(alias_def_id) = it.item_id.as_def_id()
+    {
+        // This branch of the compiler compares types structually, but does
+        // not check trait bounds. That's probably fine, since type aliases
+        // don't normally constrain on them anyway.
+        // https://github.com/rust-lang/rust/issues/21903
+        //
+        // FIXME(lazy_type_alias): Once the feature is complete or stable, rewrite this to use type unification.
+        // Be aware of `tests/rustdoc/issue-112515-impl-ty-alias.rs` which might regress.
+        let aliased_ty = tcx.type_of(alias_def_id).skip_binder();
+        let reject_cx = DeepRejectCtxt {
+            treat_obligation_params: TreatParams::AsCandidateKey,
+        };
+        v.extend(av.iter().filter(|impl_| {
+            if let Some(impl_def_id) = impl_.impl_item.item_id.as_def_id() {
+                reject_cx.types_may_unify(aliased_ty, tcx.type_of(impl_def_id).skip_binder())
+            } else {
+                false
+            }
+        }));
+    }
+    let v = {
+        let mut saw_impls = FxHashSet::default();
+        v.retain(|i| saw_impls.insert(i.def_id()));
+        v.as_slice()
+    };
 
     let mut assoc_consts = Vec::new();
     let mut methods = Vec::new();