From 482b753d66bed635dcd14c86950850e91beefd8d Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Mon, 7 Feb 2022 18:46:08 +0800
Subject: [PATCH] rustdoc: Consider enum variants when resolving assoc items in
 doc links

---
 .../passes/collect_intra_doc_links.rs         | 21 +++++++++++++++++--
 .../rustdoc/intra-doc/associated-items.rs     |  8 +++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index 8621fe6ba1b9..ae891b96ce3e 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -10,7 +10,7 @@ use rustc_hir::def::{
     PerNS,
 };
 use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_ID};
-use rustc_middle::ty::{DefIdTree, Ty, TyCtxt};
+use rustc_middle::ty::{DefIdTree, Ty, TyCtxt, TyKind};
 use rustc_middle::{bug, span_bug, ty};
 use rustc_session::lint::Lint;
 use rustc_span::hygiene::MacroKind;
@@ -723,10 +723,27 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
                 self.resolve_associated_item(res, item_name, ns, module_id)
             }
             Res::Def(
-                DefKind::Struct | DefKind::Union | DefKind::Enum | DefKind::ForeignTy,
+                def_kind @ (DefKind::Struct | DefKind::Union | DefKind::Enum | DefKind::ForeignTy),
                 did,
             ) => {
                 debug!("looking for associated item named {} for item {:?}", item_name, did);
+                // Checks if item_name is a variant of the `SomeItem` enum
+                if ns == TypeNS && def_kind == DefKind::Enum {
+                    match tcx.type_of(did).kind() {
+                        TyKind::Adt(adt_def, _) => {
+                            for variant in &adt_def.variants {
+                                if variant.name == item_name {
+                                    return Some((
+                                        root_res,
+                                        ItemFragment(FragmentKind::Variant, variant.def_id),
+                                    ));
+                                }
+                            }
+                        }
+                        _ => unreachable!(),
+                    }
+                }
+
                 // Checks if item_name belongs to `impl SomeItem`
                 let assoc_item = tcx
                     .inherent_impls(did)
diff --git a/src/test/rustdoc/intra-doc/associated-items.rs b/src/test/rustdoc/intra-doc/associated-items.rs
index 9b70ea054ad7..0b958eb8eac1 100644
--- a/src/test/rustdoc/intra-doc/associated-items.rs
+++ b/src/test/rustdoc/intra-doc/associated-items.rs
@@ -57,4 +57,12 @@ impl T2 for S {
     fn ambiguous_method() {}
 }
 
+// @has associated_items/enum.MyEnum.html '//a/@href' 'enum.MyEnum.html#variant.MyVariant'
+/// Link to [MyEnumAlias::MyVariant]
+pub enum MyEnum {
+    MyVariant,
+}
+
+pub type MyEnumAlias = MyEnum;
+
 fn main() {}