make item_primitive return impl fmt::Display

Author: yotamofek

src/librustdoc/html/render/print_item.rs

@@ -253,7 +253,7 @@ pub(super) fn print_item(cx: &Context<'_>, item: &clean::Item, buf: &mut String)
         clean::ProcMacroItem(ref m) => {
             write_str(buf, format_args!("{}", item_proc_macro(cx, item, m)))
         }
-        clean::PrimitiveItem(_) => item_primitive(buf, cx, item),
+        clean::PrimitiveItem(_) => write_str(buf, format_args!("{}", item_primitive(cx, item))),
         clean::StaticItem(ref i) => item_static(buf, cx, item, i, None),
         clean::ForeignStaticItem(ref i, safety) => item_static(buf, cx, item, i, Some(*safety)),
         clean::ConstantItem(ci) => item_constant(buf, cx, item, &ci.generics, &ci.type_, &ci.kind),
@@ -1927,18 +1927,25 @@ fn item_proc_macro<'a, 'tcx>(
     })
 }
 
-fn item_primitive(w: &mut impl fmt::Write, cx: &Context<'_>, it: &clean::Item) {
-    let def_id = it.item_id.expect_def_id();
-    write!(w, "{}", document(cx, it, None, HeadingOffset::H2)).unwrap();
-    if it.name.map(|n| n.as_str() != "reference").unwrap_or(false) {
-        write!(w, "{}", render_assoc_items(cx, it, def_id, AssocItemRender::All)).unwrap();
-    } else {
-        // We handle the "reference" primitive type on its own because we only want to list
-        // implementations on generic types.
-        let (concrete, synthetic, blanket_impl) = get_filtered_impls_for_reference(&cx.shared, it);
+fn item_primitive<'a, 'tcx>(
+    cx: &'a Context<'tcx>,
+    it: &'a clean::Item,
+) -> impl fmt::Display + 'a + Captures<'tcx> {
+    fmt::from_fn(|w| {
+        let def_id = it.item_id.expect_def_id();
+        write!(w, "{}", document(cx, it, None, HeadingOffset::H2))?;
+        if it.name.map(|n| n.as_str() != "reference").unwrap_or(false) {
+            write!(w, "{}", render_assoc_items(cx, it, def_id, AssocItemRender::All))?;
+        } else {
+            // We handle the "reference" primitive type on its own because we only want to list
+            // implementations on generic types.
+            let (concrete, synthetic, blanket_impl) =
+                get_filtered_impls_for_reference(&cx.shared, it);
 
-        render_all_impls(w, cx, it, &concrete, &synthetic, &blanket_impl);
-    }
+            render_all_impls(w, cx, it, &concrete, &synthetic, &blanket_impl);
+        }
+        Ok(())
+    })
 }
 
 fn item_constant(