rustdoc: Fill in external type parameters correctly

Type parameters were filled in for some areas, but not all. This commit unifies
the two code paths to fill in type parameters everywhere.

Closes #14508

Author: alexcrichton

src/librustdoc/clean/mod.rs

@@ -400,14 +400,19 @@ impl Clean<TyParamBound> for ast::TyParamBound {
     }
 }
 
-fn external_path(name: &str) -> Path {
+fn external_path(name: &str, substs: &ty::substs) -> Path {
     Path {
         global: false,
         segments: vec![PathSegment {
             name: name.to_string(),
-            lifetimes: Vec::new(),
-            types: Vec::new(),
-        }]
+            lifetimes: match substs.regions {
+                ty::ErasedRegions => Vec::new(),
+                ty::NonerasedRegions(ref v) => {
+                    v.iter().filter_map(|v| v.clean()).collect()
+                }
+            },
+            types: substs.tps.clean(),
+        }],
     }
 }
 
@@ -418,16 +423,21 @@ impl Clean<TyParamBound> for ty::BuiltinBound {
             core::Typed(ref tcx) => tcx,
             core::NotTyped(_) => return RegionBound,
         };
+        let empty = ty::substs::empty();
         let (did, path) = match *self {
             ty::BoundStatic => return RegionBound,
             ty::BoundSend =>
-                (tcx.lang_items.send_trait().unwrap(), external_path("Send")),
+                (tcx.lang_items.send_trait().unwrap(),
+                 external_path("Send", &empty)),
             ty::BoundSized =>
-                (tcx.lang_items.sized_trait().unwrap(), external_path("Sized")),
+                (tcx.lang_items.sized_trait().unwrap(),
+                 external_path("Sized", &empty)),
             ty::BoundCopy =>
-                (tcx.lang_items.copy_trait().unwrap(), external_path("Copy")),
+                (tcx.lang_items.copy_trait().unwrap(),
+                 external_path("Copy", &empty)),
             ty::BoundShare =>
-                (tcx.lang_items.share_trait().unwrap(), external_path("Share")),
+                (tcx.lang_items.share_trait().unwrap(),
+                 external_path("Share", &empty)),
         };
         let fqn = csearch::get_item_path(tcx, did);
         let fqn = fqn.move_iter().map(|i| i.to_str().to_string()).collect();
@@ -451,7 +461,8 @@ impl Clean<TyParamBound> for ty::TraitRef {
         let fqn = csearch::get_item_path(tcx, self.def_id);
         let fqn = fqn.move_iter().map(|i| i.to_str().to_string())
                      .collect::<Vec<String>>();
-        let path = external_path(fqn.last().unwrap().as_slice());
+        let path = external_path(fqn.last().unwrap().as_slice(),
+                                 &self.substs);
         cx.external_paths.borrow_mut().get_mut_ref().insert(self.def_id,
                                                             (fqn, TypeTrait));
         TraitBound(ResolvedPath {
@@ -1040,26 +1051,16 @@ impl Clean<Type> for ty::t {
                 let fqn: Vec<String> = fqn.move_iter().map(|i| {
                     i.to_str().to_string()
                 }).collect();
-                let mut path = external_path(fqn.last()
-                                                .unwrap()
-                                                .to_str()
-                                                .as_slice());
                 let kind = match ty::get(*self).sty {
                     ty::ty_struct(..) => TypeStruct,
                     ty::ty_trait(..) => TypeTrait,
                     _ => TypeEnum,
                 };
-                path.segments.get_mut(0).lifetimes = match substs.regions {
-                    ty::ErasedRegions => Vec::new(),
-                    ty::NonerasedRegions(ref v) => {
-                        v.iter().filter_map(|v| v.clean()).collect()
-                    }
-                };
-                path.segments.get_mut(0).types = substs.tps.clean();
                 cx.external_paths.borrow_mut().get_mut_ref().insert(did,
                                                                     (fqn, kind));
                 ResolvedPath {
-                    path: path,
+                    path: external_path(fqn.last().unwrap().to_str().as_slice(),
+                                        substs),
                     typarams: None,
                     did: did,
                 }