Support inlined cross-crate re-exported trait aliases

1 files changed, 22 insertions, 21 deletions

diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index 3a2b6974681..2ea0fd8ad6c 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -67,9 +67,13 @@ pub(crate) fn try_inline(
             record_extern_fqn(cx, did, ItemType::Trait);
             cx.with_param_env(did, |cx| {
                 build_impls(cx, did, attrs_without_docs, &mut ret);
-                clean::TraitItem(Box::new(build_external_trait(cx, did)))
+                clean::TraitItem(Box::new(build_trait(cx, did)))
             })
         }
+        Res::Def(DefKind::TraitAlias, did) => {
+            record_extern_fqn(cx, did, ItemType::TraitAlias);
+            cx.with_param_env(did, |cx| clean::TraitAliasItem(build_trait_alias(cx, did)))
+        }
         Res::Def(DefKind::Fn, did) => {
             record_extern_fqn(cx, did, ItemType::Function);
             cx.with_param_env(did, |cx| {
@@ -251,7 +255,7 @@ pub(crate) fn record_extern_fqn(cx: &mut DocContext<'_>, did: DefId, kind: ItemT
     }
 }
 
-pub(crate) fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean::Trait {
+pub(crate) fn build_trait(cx: &mut DocContext<'_>, did: DefId) -> clean::Trait {
     let trait_items = cx
         .tcx
         .associated_items(did)
@@ -263,11 +267,18 @@ pub(crate) fn build_external_trait(cx: &mut DocContext<'_>, did: DefId) -> clean
     let predicates = cx.tcx.predicates_of(did);
     let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
     let generics = filter_non_trait_generics(did, generics);
-    let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
+    let (generics, supertrait_bounds) = separate_self_bounds(generics);
     clean::Trait { def_id: did, generics, items: trait_items, bounds: supertrait_bounds }
 }
 
-pub(crate) fn build_function(cx: &mut DocContext<'_>, def_id: DefId) -> Box<clean::Function> {
+fn build_trait_alias(cx: &mut DocContext<'_>, did: DefId) -> clean::TraitAlias {
+    let predicates = cx.tcx.predicates_of(did);
+    let generics = clean_ty_generics(cx, cx.tcx.generics_of(did), predicates);
+    let (generics, bounds) = separate_self_bounds(generics);
+    clean::TraitAlias { generics, bounds }
+}
+
+pub(super) fn build_function(cx: &mut DocContext<'_>, def_id: DefId) -> Box<clean::Function> {
     let sig = cx.tcx.fn_sig(def_id).instantiate_identity();
     // The generics need to be cleaned before the signature.
     let mut generics =
@@ -788,12 +799,7 @@ fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean:
     g
 }
 
-/// Supertrait bounds for a trait are also listed in the generics coming from
-/// the metadata for a crate, so we want to separate those out and create a new
-/// list of explicit supertrait bounds to render nicely.
-fn separate_supertrait_bounds(
-    mut g: clean::Generics,
-) -> (clean::Generics, Vec<clean::GenericBound>) {
+fn separate_self_bounds(mut g: clean::Generics) -> (clean::Generics, Vec<clean::GenericBound>) {
     let mut ty_bounds = Vec::new();
     g.where_predicates.retain(|pred| match *pred {
         clean::WherePredicate::BoundPredicate { ty: clean::SelfTy, ref bounds, .. } => {
@@ -806,22 +812,17 @@ fn separate_supertrait_bounds(
 }
 
 pub(crate) fn record_extern_trait(cx: &mut DocContext<'_>, did: DefId) {
-    if did.is_local() {
-        return;
-    }
-
+    if did.is_local()
+        || cx.external_traits.contains_key(&did)
+        || cx.active_extern_traits.contains(&did)
     {
-        if cx.external_traits.contains_key(&did) || cx.active_extern_traits.contains(&did) {
-            return;
-        }
+        return;
     }
 
-    {
-        cx.active_extern_traits.insert(did);
-    }
+    cx.active_extern_traits.insert(did);
 
     debug!("record_extern_trait: {did:?}");
-    let trait_ = build_external_trait(cx, did);
+    let trait_ = build_trait(cx, did);
 
     cx.external_traits.insert(did, trait_);
     cx.active_extern_traits.remove(&did);