Rollup merge of #83055 - aDotInTheVoid:selective-strip-item-doc, r=jyn514

[rustdoc] Don't document stripped items in JSON renderer.

Fixes #80664, see [my comment there](https://github.com/rust-lang/rust/issues/80664#issuecomment-797557948) for why

Note that we already do something similar in `convert_item`:

https://github.com/rust-lang/rust/blob/bb4cdf8ec034dca5c056ec9295f38062e5b7e871/src/librustdoc/json/conversions.rs#L28-L31

``@rustbot`` modify labels: +T-rustdoc +A-rustdoc-json

r? ``@jyn514``
cc ``@CraftSpider``

2 files changed, 7 insertions, 2 deletions

diff --git a/src/librustdoc/json/conversions.rs b/src/librustdoc/json/conversions.rs
index 7516fc1eaa1..c470dc57005 100644
--- a/src/librustdoc/json/conversions.rs
+++ b/src/librustdoc/json/conversions.rs
@@ -198,7 +198,8 @@ fn from_clean_item_kind(item: clean::ItemKind, tcx: TyCtxt<'_>, name: &Option<Sy
             bounds: g.into_iter().map(|x| x.into_tcx(tcx)).collect(),
             default: t.map(|x| x.into_tcx(tcx)),
         },
-        StrippedItem(inner) => from_clean_item_kind(*inner, tcx, name),
+        // `convert_item` early returns `None` for striped items
+        StrippedItem(_) => unreachable!(),
         PrimitiveItem(_) | KeywordItem(_) => {
             panic!("{:?} is not supported for JSON output", item)
         }
diff --git a/src/librustdoc/json/mod.rs b/src/librustdoc/json/mod.rs
index 6d18dbe67e4..db3a0c5ceb1 100644
--- a/src/librustdoc/json/mod.rs
+++ b/src/librustdoc/json/mod.rs
@@ -129,6 +129,8 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
         "json"
     }
 
+    const RUN_ON_MODULE: bool = false;
+
     fn init(
         krate: clean::Crate,
         options: RenderOptions,
@@ -169,8 +171,10 @@ impl<'tcx> FormatRenderer<'tcx> for JsonRenderer<'tcx> {
                 e.impls = self.get_impls(id)
             }
             let removed = self.index.borrow_mut().insert(from_def_id(id), new_item.clone());
+
             // FIXME(adotinthevoid): Currently, the index is duplicated. This is a sanity check
-            // to make sure the items are unique.
+            // to make sure the items are unique. The main place this happens is when an item, is
+            // reexported in more than one place. See `rustdoc-json/reexport/in_root_and_mod`
             if let Some(old_item) = removed {
                 assert_eq!(old_item, new_item);
             }