use a HashSet instead of IndexSet for cache of types with notable trait impls

iteration order shouldn't matter

Author: yotamofek

src/librustdoc/html/render/context.rs

@@ -5,7 +5,7 @@ use std::path::{Path, PathBuf};
 use std::sync::mpsc::{Receiver, channel};
 
 use rinja::Template;
-use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet};
+use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap};
 use rustc_hir::def_id::{DefIdMap, LOCAL_CRATE};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
@@ -60,7 +60,7 @@ pub(crate) struct Context<'tcx> {
     /// [#82381]: https://github.com/rust-lang/rust/issues/82381
     pub(crate) shared: SharedContext<'tcx>,
     /// Collection of all types with notable traits referenced in the current module.
-    pub(crate) types_with_notable_traits: RefCell<FxIndexSet<clean::Type>>,
+    pub(crate) types_with_notable_traits: RefCell<FxHashSet<clean::Type>>,
     /// Contains information that needs to be saved and reset after rendering an item which is
     /// not a module.
     pub(crate) info: ContextInfo,
@@ -579,7 +579,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
             id_map: RefCell::new(id_map),
             deref_id_map: Default::default(),
             shared: scx,
-            types_with_notable_traits: RefCell::new(FxIndexSet::default()),
+            types_with_notable_traits: RefCell::default(),
             info: ContextInfo::new(include_sources),
         };
 

src/librustdoc/html/render/mod.rs

@@ -1545,10 +1545,10 @@ fn notable_traits_decl(ty: &clean::Type, cx: &Context<'_>) -> (String, String) {
     (format!("{:#}", ty.print(cx)), out.into_inner())
 }
 
-pub(crate) fn notable_traits_json<'a>(
-    tys: impl Iterator<Item = &'a clean::Type>,
-    cx: &Context<'_>,
-) -> String {
+pub(crate) fn notable_traits_json(tys: &FxHashSet<clean::Type>, cx: &Context<'_>) -> String {
+    #[expect(rustc::potential_query_instability, reason = "items are sorted by name")]
+    let tys = tys.iter();
+
     let mut mp: Vec<(String, String)> = tys.map(|ty| notable_traits_decl(ty, cx)).collect();
     mp.sort_by(|(name1, _html1), (name2, _html2)| name1.cmp(name2));
     struct NotableTraitsMap(Vec<(String, String)>);

src/librustdoc/html/render/print_item.rs

@@ -281,7 +281,7 @@ pub(super) fn print_item(cx: &Context<'_>, item: &clean::Item, buf: &mut Buffer)
         write!(
             buf,
             r#"<script type="text/json" id="notable-traits-data">{}</script>"#,
-            notable_traits_json(types_with_notable_traits.iter(), cx)
+            notable_traits_json(&types_with_notable_traits, cx)
         );
         types_with_notable_traits.clear();
     }