From 071d8b14dab01f636aa4c8ec707a59a00bfa356d Mon Sep 17 00:00:00 2001
From: Hannah McLaughlin <h@mcla.ug>
Date: Sun, 15 Nov 2020 20:45:52 +0000
Subject: [PATCH 1/3] Fix rustdoc: Referencing methods on extern_types does not
 resolve #78777: handle DefKind::ForeignTy variant

---
 src/librustdoc/passes/collect_intra_doc_links.rs | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/src/librustdoc/passes/collect_intra_doc_links.rs b/src/librustdoc/passes/collect_intra_doc_links.rs
index 895414b1d7e4c..fd09ba04b3db9 100644
--- a/src/librustdoc/passes/collect_intra_doc_links.rs
+++ b/src/librustdoc/passes/collect_intra_doc_links.rs
@@ -492,7 +492,14 @@ impl<'a, 'tcx> LinkCollector<'a, 'tcx> {
             Res::PrimTy(prim) => Some(
                 self.resolve_primitive_associated_item(prim, ns, module_id, item_name, item_str),
             ),
-            Res::Def(DefKind::Struct | DefKind::Union | DefKind::Enum | DefKind::TyAlias, did) => {
+            Res::Def(
+                DefKind::Struct
+                | DefKind::Union
+                | DefKind::Enum
+                | DefKind::TyAlias
+                | DefKind::ForeignTy,
+                did,
+            ) => {
                 debug!("looking for associated item named {} for item {:?}", item_name, did);
                 // Checks if item_name belongs to `impl SomeItem`
                 let assoc_item = cx

From d38dbcb19f6ef1c5ffcf7869767674ef3d6d045f Mon Sep 17 00:00:00 2001
From: Hannah McLaughlin <h@mcla.ug>
Date: Sun, 15 Nov 2020 21:14:00 +0000
Subject: [PATCH 2/3] Improve error message when we try to get_type on
 something that does not have a type

---
 compiler/rustc_metadata/src/rmeta/decoder.rs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_metadata/src/rmeta/decoder.rs b/compiler/rustc_metadata/src/rmeta/decoder.rs
index a1df1a63fc58d..19340dd51de14 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder.rs
@@ -947,7 +947,12 @@ impl<'a, 'tcx> CrateMetadataRef<'a> {
     }
 
     fn get_type(&self, id: DefIndex, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
-        self.root.tables.ty.get(self, id).unwrap().decode((self, tcx))
+        self.root
+            .tables
+            .ty
+            .get(self, id)
+            .unwrap_or_else(|| panic!("Not a type: {:?}", id))
+            .decode((self, tcx))
     }
 
     fn get_stability(&self, id: DefIndex) -> Option<attr::Stability> {

From 32cd4bc790ae8a4b0d7105e2a70de90616a5a621 Mon Sep 17 00:00:00 2001
From: Hannah McLaughlin <h@mcla.ug>
Date: Wed, 18 Nov 2020 22:14:58 +0000
Subject: [PATCH 3/3] Add test

---
 src/test/rustdoc/intra-link-extern-type.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)
 create mode 100644 src/test/rustdoc/intra-link-extern-type.rs

diff --git a/src/test/rustdoc/intra-link-extern-type.rs b/src/test/rustdoc/intra-link-extern-type.rs
new file mode 100644
index 0000000000000..418e0d91ea7ef
--- /dev/null
+++ b/src/test/rustdoc/intra-link-extern-type.rs
@@ -0,0 +1,18 @@
+#![feature(extern_types)]
+
+extern {
+    pub type ExternType;
+}
+
+impl ExternType {
+    pub fn f(&self) {
+
+    }
+}
+
+// @has 'intra_link_extern_type/foreigntype.ExternType.html'
+// @has 'intra_link_extern_type/fn.links_to_extern_type.html' \
+// 'href="../intra_link_extern_type/foreigntype.ExternType.html#method.f"'
+/// See also [ExternType::f]
+pub fn links_to_extern_type() {
+}