fix doc links on extern crate items

src/librustdoc/clean/mod.rs

@@ -2643,15 +2643,12 @@ fn clean_extern_crate<'tcx>(
         }
     }
 
-    // FIXME: using `from_def_id_and_kind` breaks `rustdoc/masked` for some reason
-    vec![Item {
-        name: Some(name),
-        attrs: Box::new(Attributes::from_ast(attrs)),
-        item_id: crate_def_id.into(),
-        kind: Box::new(ExternCrateItem { src: orig_name }),
-        cfg: attrs.cfg(cx.tcx, &cx.cache.hidden_cfg),
-        inline_stmt_id: Some(krate_owner_def_id),
-    }]
+    vec![Item::from_def_id_and_parts(
+        krate_owner_def_id,
+        Some(name),
+        ExternCrateItem { src: orig_name },
+        cx,
+    )]
 }
 
 fn clean_use_statement<'tcx>(

src/librustdoc/clean/utils.rs

@@ -38,11 +38,15 @@ pub(crate) fn krate(cx: &mut DocContext<'_>) -> Crate {
             for it in &module.items {
                 // `compiler_builtins` should be masked too, but we can't apply
                 // `#[doc(masked)]` to the injected `extern crate` because it's unstable.
-                if it.is_extern_crate()
-                    && (it.attrs.has_doc_flag(sym::masked)
-                        || cx.tcx.is_compiler_builtins(it.item_id.krate()))
-                {
+                if cx.tcx.is_compiler_builtins(it.item_id.krate()) {
                     cx.cache.masked_crates.insert(it.item_id.krate());
+                } else if it.is_extern_crate()
+                    && it.attrs.has_doc_flag(sym::masked)
+                    && let Some(def_id) = it.item_id.as_def_id()
+                    && let Some(local_def_id) = def_id.as_local()
+                    && let Some(cnum) = cx.tcx.extern_mod_stmt_cnum(local_def_id)
+                {
+                    cx.cache.masked_crates.insert(cnum);
                 }
             }
         }

src/librustdoc/html/format.rs

@@ -18,7 +18,7 @@
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::def::DefKind;
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::{DefId, LOCAL_CRATE};
 use rustc_metadata::creader::{CStore, LoadedMacro};
 use rustc_middle::ty;
 use rustc_middle::ty::TyCtxt;
@@ -662,6 +662,14 @@ pub(crate) fn href_with_root_path(
             // documented on their parent's page
             tcx.parent(did)
         }
+        DefKind::ExternCrate => {
+            // Link to the crate itself, not the `extern crate` item.
+            if let Some(local_did) = did.as_local() {
+                tcx.extern_mod_stmt_cnum(local_did).unwrap_or(LOCAL_CRATE).as_def_id()
+            } else {
+                did
+            }
+        }
         _ => did,
     };
     let cache = cx.cache();

tests/rustdoc/issue-33178.rs

@@ -4,10 +4,11 @@
 // ignore-cross-compile
 
 // @has issue_33178/index.html
-// @has - //a/@title empty
-// @has - //a/@href ../empty/index.html
+// @has - '//a[@title="mod empty"][@href="../empty/index.html"]' empty
 pub extern crate empty;
 
-// @has - //a/@title variant_struct
-// @has - //a/@href ../variant_struct/index.html
+// @has - '//a[@title="mod variant_struct"][@href="../variant_struct/index.html"]' variant_struct
 pub extern crate variant_struct as foo;
+
+// @has - '//a[@title="mod issue_33178"][@href="index.html"]' self
+pub extern crate self as bar;