Rollup merge of #80845 - GuillaumeGomez:item-kind-transition, r=jyn514

Make ItemKind::ExternCrate looks like hir::ItemKind::ExternCrate to make transition over hir::ItemKind simpler

It was surprisingly difficult to make this change, mostly because of two issues:

* We now store the `ExternCrate` name in the parent struct (`clean::Item`), which forced me to modify the json conversion code a bit more than expected.
* The second problem was that, since we now have a `Some(name)`, it was trying to render it, ending up in a panic because we ended up in a `unreachable` statement. The solution was simply to add `!item.is_extern_crate()` in `formats::renderer` before calling `cx.item(item, &cache)?;`.

I'll continue to replace all the `clean::ItemKind` variants one by one until it looks exactly like `hir::ItemKind`. Then we'll simply discard the rustdoc type. Once this done, we'll be able to discard `clean::Item` too to use `hir::Item`.

r? ``@jyn514``

1 files changed, 3 insertions, 3 deletions

diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index 6d61248f28e..6cdd3838023 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -240,7 +240,7 @@ fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[cl
         }
 
         match *myitem.kind {
-            clean::ExternCrateItem(ref name, ref src) => {
+            clean::ExternCrateItem { ref src } => {
                 use crate::html::format::anchor;
 
                 match *src {
@@ -249,13 +249,13 @@ fn item_module(w: &mut Buffer, cx: &Context<'_>, item: &clean::Item, items: &[cl
                         "<tr><td><code>{}extern crate {} as {};",
                         myitem.visibility.print_with_space(cx.tcx(), myitem.def_id, cx.cache()),
                         anchor(myitem.def_id, &*src.as_str(), cx.cache()),
-                        name
+                        myitem.name.as_ref().unwrap(),
                     ),
                     None => write!(
                         w,
                         "<tr><td><code>{}extern crate {};",
                         myitem.visibility.print_with_space(cx.tcx(), myitem.def_id, cx.cache()),
-                        anchor(myitem.def_id, &*name.as_str(), cx.cache())
+                        anchor(myitem.def_id, &*myitem.name.as_ref().unwrap().as_str(), cx.cache()),
                     ),
                 }
                 w.write_str("</code></td></tr>");