From e0b71fff2a052a83ad00ead18b01149581f4e0e2 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Thu, 21 Apr 2022 01:09:48 +0300
Subject: [PATCH] [WIP] rustdoc: Resolve some more doc links early

---
 .../src/rmeta/decoder/cstore_impl.rs          |  8 ++++++
 src/librustdoc/lib.rs                         |  1 +
 .../passes/collect_intra_doc_links/early.rs   | 26 ++++++++++++++-----
 3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index 6b1f7d55026ad..1156a78e8a94a 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -532,6 +532,14 @@ impl CStore {
         self.get_crate_data(cnum).get_all_incoherent_impls()
     }
 
+    pub fn associated_item_def_ids_untracked<'a>(
+        &'a self,
+        def_id: DefId,
+        sess: &'a Session,
+    ) -> impl Iterator<Item = DefId> + 'a {
+        self.get_crate_data(def_id.krate).get_associated_item_def_ids(def_id.index, sess)
+    }
+
     pub fn may_have_doc_links_untracked(&self, def_id: DefId) -> bool {
         self.get_crate_data(def_id.krate).get_may_have_doc_links(def_id.index)
     }
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 0fcfabba4c0a1..cd196a0184799 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -795,6 +795,7 @@ fn main_options(options: config::Options) -> MainResult {
                 let resolver_caches = resolver.borrow_mut().access(|resolver| {
                     collect_intra_doc_links::early_resolve_intra_doc_links(
                         resolver,
+                        sess,
                         krate,
                         externs,
                         document_private,
diff --git a/src/librustdoc/passes/collect_intra_doc_links/early.rs b/src/librustdoc/passes/collect_intra_doc_links/early.rs
index e2359da870edc..98dba658cc63a 100644
--- a/src/librustdoc/passes/collect_intra_doc_links/early.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links/early.rs
@@ -14,6 +14,7 @@ use rustc_hir::TraitCandidate;
 use rustc_middle::ty::{DefIdTree, Visibility};
 use rustc_resolve::{ParentScope, Resolver};
 use rustc_session::config::Externs;
+use rustc_session::Session;
 use rustc_span::{Symbol, SyntaxContext};
 
 use std::collections::hash_map::Entry;
@@ -21,12 +22,14 @@ use std::mem;
 
 crate fn early_resolve_intra_doc_links(
     resolver: &mut Resolver<'_>,
+    sess: &Session,
     krate: &ast::Crate,
     externs: Externs,
     document_private_items: bool,
 ) -> ResolverCaches {
     let mut link_resolver = EarlyDocLinkResolver {
         resolver,
+        sess,
         current_mod: CRATE_DEF_ID,
         visited_mods: Default::default(),
         markdown_links: Default::default(),
@@ -70,6 +73,7 @@ fn doc_attrs<'a>(attrs: impl Iterator<Item = &'a ast::Attribute>) -> Attributes
 
 struct EarlyDocLinkResolver<'r, 'ra> {
     resolver: &'r mut Resolver<'ra>,
+    sess: &'r Session,
     current_mod: LocalDefId,
     visited_mods: DefIdSet,
     markdown_links: FxHashMap<String, Vec<PreprocessedMarkdownLink>>,
@@ -167,14 +171,22 @@ impl EarlyDocLinkResolver<'_, '_> {
         }
     }
 
-    fn resolve_doc_links_extern_impl(&mut self, def_id: DefId, _is_inherent: bool) {
-        // FIXME: Resolve links in associated items in addition to traits themselves,
-        // `force` is used to provide traits in scope for the associated items.
-        self.resolve_doc_links_extern_outer(def_id, def_id, true);
+    fn resolve_doc_links_extern_impl(&mut self, def_id: DefId, is_inherent: bool) {
+        self.resolve_doc_links_extern_outer(def_id, def_id);
+        let assoc_item_def_ids = Vec::from_iter(
+            self.resolver.cstore().associated_item_def_ids_untracked(def_id, self.sess),
+        );
+        for assoc_def_id in assoc_item_def_ids {
+            if !is_inherent
+                || self.resolver.cstore().visibility_untracked(assoc_def_id) == Visibility::Public
+            {
+                self.resolve_doc_links_extern_outer(assoc_def_id, def_id);
+            }
+        }
     }
 
-    fn resolve_doc_links_extern_outer(&mut self, def_id: DefId, scope_id: DefId, force: bool) {
-        if !force && !self.resolver.cstore().may_have_doc_links_untracked(def_id) {
+    fn resolve_doc_links_extern_outer(&mut self, def_id: DefId, scope_id: DefId) {
+        if !self.resolver.cstore().may_have_doc_links_untracked(def_id) {
             return;
         }
         // FIXME: actually resolve links, not just add traits in scope.
@@ -246,7 +258,7 @@ impl EarlyDocLinkResolver<'_, '_> {
                         Res::Def(DefKind::Variant, ..) => self.resolver.parent(def_id).unwrap(),
                         _ => def_id,
                     };
-                    self.resolve_doc_links_extern_outer(def_id, scope_id, false); // Outer attribute scope
+                    self.resolve_doc_links_extern_outer(def_id, scope_id); // Outer attribute scope
                     if let Res::Def(DefKind::Mod, ..) = child.res {
                         self.resolve_doc_links_extern_inner(def_id); // Inner attribute scope
                     }