Remove unnecessary provided_trait_methods field from Impl

It can be calculated on-demand.

src/librustdoc/clean/auto_trait.rs

@@ -118,7 +118,6 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
                 span: Span::dummy(),
                 unsafety: hir::Unsafety::Normal,
                 generics: new_generics,
-                provided_trait_methods: Default::default(),
                 trait_: Some(trait_ref.clean(self.cx).get_trait_type().unwrap()),
                 for_: ty.clean(self.cx),
                 items: Vec::new(),

src/librustdoc/clean/blanket_impl.rs

@@ -92,12 +92,6 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                 }
 
                 self.cx.generated_synthetics.insert((ty, trait_def_id));
-                let provided_trait_methods = self
-                    .cx
-                    .tcx
-                    .provided_trait_methods(trait_def_id)
-                    .map(|meth| meth.ident.name)
-                    .collect();
 
                 impls.push(Item {
                     name: None,
@@ -112,7 +106,6 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                             self.cx.tcx.explicit_predicates_of(impl_def_id),
                         )
                             .clean(self.cx),
-                        provided_trait_methods,
                         // FIXME(eddyb) compute both `trait_` and `for_` from
                         // the post-inference `trait_ref`, as it's more accurate.
                         trait_: Some(trait_ref.clean(self.cx).get_trait_type().unwrap()),

src/librustdoc/clean/inline.rs

@@ -414,24 +414,17 @@ crate fn build_impl(
         record_extern_trait(cx, trait_did);
     }
 
-    let provided = trait_
-        .def_id()
-        .map(|did| tcx.provided_trait_methods(did).map(|meth| meth.ident.name).collect())
-        .unwrap_or_default();
-
-    debug!("build_impl: impl {:?} for {:?}", trait_.def_id(), for_.def_id());
-
     let (merged_attrs, cfg) = merge_attrs(cx, parent_module.into(), load_attrs(cx, did), attrs);
     debug!("merged_attrs={:?}", merged_attrs);
 
+    debug!("build_impl: impl {:?} for {:?}", trait_.def_id(), for_.def_id());
     ret.push(clean::Item::from_def_id_and_attrs_and_parts(
         did,
         None,
         clean::ImplItem(clean::Impl {
             span: clean::types::rustc_span(did, cx.tcx),
             unsafety: hir::Unsafety::Normal,
             generics,
-            provided_trait_methods: provided,
             trait_,
             for_,
             items: trait_items,

src/librustdoc/clean/mod.rs

@@ -1930,11 +1930,6 @@ fn clean_impl(impl_: &hir::Impl<'_>, hir_id: hir::HirId, cx: &mut DocContext<'_>
         build_deref_target_impls(cx, &items, &mut ret);
     }
 
-    let provided: FxHashSet<Symbol> = trait_
-        .def_id()
-        .map(|did| tcx.provided_trait_methods(did).map(|meth| meth.ident.name).collect())
-        .unwrap_or_default();
-
     let for_ = impl_.self_ty.clean(cx);
     let type_alias = for_.def_id().and_then(|did| match tcx.def_kind(did) {
         DefKind::TyAlias => Some(tcx.type_of(did).clean(cx)),
@@ -1945,7 +1940,6 @@ fn clean_impl(impl_: &hir::Impl<'_>, hir_id: hir::HirId, cx: &mut DocContext<'_>
             span: types::rustc_span(tcx.hir().local_def_id(hir_id).to_def_id(), tcx),
             unsafety: impl_.unsafety,
             generics: impl_.generics.clean(cx),
-            provided_trait_methods: provided.clone(),
             trait_,
             for_,
             items,

src/librustdoc/clean/types.rs

@@ -2150,7 +2150,6 @@ crate struct Impl {
     crate span: Span,
     crate unsafety: hir::Unsafety,
     crate generics: Generics,
-    crate provided_trait_methods: FxHashSet<Symbol>,
     crate trait_: Option<Type>,
     crate for_: Type,
     crate items: Vec<Item>,
@@ -2159,6 +2158,15 @@ crate struct Impl {
     crate blanket_impl: Option<Type>,
 }
 
+impl Impl {
+    crate fn provided_trait_methods(&self, tcx: TyCtxt<'_>) -> FxHashSet<Symbol> {
+        self.trait_
+            .def_id()
+            .map(|did| tcx.provided_trait_methods(did).map(|meth| meth.ident.name).collect())
+            .unwrap_or_default()
+    }
+}
+
 #[derive(Clone, Debug)]
 crate struct Import {
     crate kind: ImportKind,

src/librustdoc/html/render/mod.rs

@@ -726,7 +726,8 @@ fn render_impls(
         .iter()
         .map(|i| {
             let did = i.trait_did_full(cache).unwrap();
-            let assoc_link = AssocItemLink::GotoSource(did, &i.inner_impl().provided_trait_methods);
+            let provided_trait_methods = i.inner_impl().provided_trait_methods(tcx);
+            let assoc_link = AssocItemLink::GotoSource(did, &provided_trait_methods);
             let mut buffer = if w.is_for_html() { Buffer::html() } else { Buffer::new() };
             render_impl(
                 &mut buffer,
@@ -1490,7 +1491,8 @@ fn render_impl(
                 continue;
             }
             let did = i.trait_.as_ref().unwrap().def_id_full(cx.cache()).unwrap();
-            let assoc_link = AssocItemLink::GotoSource(did, &i.provided_trait_methods);
+            let provided_methods = i.provided_trait_methods(cx.tcx());
+            let assoc_link = AssocItemLink::GotoSource(did, &provided_methods);
 
             doc_impl_item(
                 w,

src/librustdoc/html/render/print_item.rs

@@ -669,10 +669,9 @@ fn item_trait(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Tra
             write_small_section_header(w, "foreign-impls", "Implementations on Foreign Types", "");
 
             for implementor in foreign {
-                let assoc_link = AssocItemLink::GotoSource(
-                    implementor.impl_item.def_id,
-                    &implementor.inner_impl().provided_trait_methods,
-                );
+                let provided_methods = implementor.inner_impl().provided_trait_methods(cx.tcx());
+                let assoc_link =
+                    AssocItemLink::GotoSource(implementor.impl_item.def_id, &provided_methods);
                 render_impl(
                     w,
                     cx,

src/librustdoc/json/conversions.rs

@@ -453,10 +453,10 @@ impl FromWithTcx<clean::Trait> for Trait {
 
 impl FromWithTcx<clean::Impl> for Impl {
     fn from_tcx(impl_: clean::Impl, tcx: TyCtxt<'_>) -> Self {
+        let provided_trait_methods = impl_.provided_trait_methods(tcx);
         let clean::Impl {
             unsafety,
             generics,
-            provided_trait_methods,
             trait_,
             for_,
             items,