Remove many RefCells from DocContext

I left some of them so this change doesn't balloon in size and because
removing the RefCell in `DocContext.resolver` would require compiler
changes.

Thanks to `@jyn514` for making this a lot easier with rust-lang#82020!

Author: camelid

src/librustdoc/clean/auto_trait.rs

@@ -41,7 +41,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
     ) -> Option<Item> {
         let tcx = self.cx.tcx;
         let trait_ref = ty::TraitRef { def_id: trait_def_id, substs: tcx.mk_substs_trait(ty, &[]) };
-        if !self.cx.generated_synthetics.borrow_mut().insert((ty, trait_def_id)) {
+        if !self.cx.generated_synthetics.insert((ty, trait_def_id)) {
             debug!("get_auto_trait_impl_for({:?}): already generated, aborting", trait_ref);
             return None;
         }

src/librustdoc/clean/blanket_impl.rs

@@ -22,8 +22,8 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
         debug!("get_blanket_impls({:?})", ty);
         let mut impls = Vec::new();
         for &trait_def_id in self.cx.tcx.all_traits(LOCAL_CRATE).iter() {
-            if !self.cx.renderinfo.borrow().access_levels.is_public(trait_def_id)
-                || self.cx.generated_synthetics.borrow_mut().get(&(ty, trait_def_id)).is_some()
+            if !self.cx.renderinfo.access_levels.is_public(trait_def_id)
+                || self.cx.generated_synthetics.get(&(ty, trait_def_id)).is_some()
             {
                 continue;
             }
@@ -94,7 +94,7 @@ impl<'a, 'tcx> BlanketImplFinder<'a, 'tcx> {
                     return;
                 }
 
-                self.cx.generated_synthetics.borrow_mut().insert((ty, trait_def_id));
+                self.cx.generated_synthetics.insert((ty, trait_def_id));
                 let provided_trait_methods = self
                     .cx
                     .tcx

src/librustdoc/clean/inline.rs

@@ -122,7 +122,7 @@ crate fn try_inline(
     let target_attrs = load_attrs(cx, did);
     let attrs = box merge_attrs(cx, Some(parent_module), target_attrs, attrs_clone);
 
-    cx.renderinfo.borrow_mut().inlined.insert(did);
+    cx.renderinfo.inlined.insert(did);
     let what_rustc_thinks = clean::Item::from_def_id_and_parts(did, Some(name), kind, cx);
     ret.push(clean::Item { attrs, ..what_rustc_thinks });
     Some(ret)
@@ -156,7 +156,7 @@ crate fn load_attrs<'hir>(cx: &DocContext<'hir>, did: DefId) -> Attrs<'hir> {
 ///
 /// These names are used later on by HTML rendering to generate things like
 /// source links back to the original item.
-crate fn record_extern_fqn(cx: &DocContext<'_>, did: DefId, kind: clean::TypeKind) {
+crate fn record_extern_fqn(cx: &mut DocContext<'_>, did: DefId, kind: clean::TypeKind) {
     let crate_name = cx.tcx.crate_name(did.krate).to_string();
 
     let relative = cx.tcx.def_path(did).data.into_iter().filter_map(|elem| {
@@ -181,9 +181,9 @@ crate fn record_extern_fqn(cx: &DocContext<'_>, did: DefId, kind: clean::TypeKin
     };
 
     if did.is_local() {
-        cx.renderinfo.borrow_mut().exact_paths.insert(did, fqn);
+        cx.renderinfo.exact_paths.insert(did, fqn);
     } else {
-        cx.renderinfo.borrow_mut().external_paths.insert(did, (fqn, kind));
+        cx.renderinfo.external_paths.insert(did, (fqn, kind));
     }
 }
 
@@ -317,7 +317,7 @@ crate fn build_impl(
     attrs: Option<Attrs<'_>>,
     ret: &mut Vec<clean::Item>,
 ) {
-    if !cx.renderinfo.borrow_mut().inlined.insert(did) {
+    if !cx.renderinfo.inlined.insert(did) {
         return;
     }
 
@@ -329,7 +329,7 @@ crate fn build_impl(
     if !did.is_local() {
         if let Some(traitref) = associated_trait {
             let did = traitref.def_id;
-            if !cx.renderinfo.borrow().access_levels.is_public(did) {
+            if !cx.renderinfo.access_levels.is_public(did) {
                 return;
             }
 
@@ -361,7 +361,7 @@ crate fn build_impl(
     // reachable in rustdoc generated documentation
     if !did.is_local() {
         if let Some(did) = for_.def_id() {
-            if !cx.renderinfo.borrow().access_levels.is_public(did) {
+            if !cx.renderinfo.access_levels.is_public(did) {
                 return;
             }
 
@@ -613,20 +613,19 @@ crate fn record_extern_trait(cx: &mut DocContext<'_>, did: DefId) {
     }
 
     {
-        if cx.external_traits.borrow().contains_key(&did)
-            || cx.active_extern_traits.borrow().contains(&did)
+        if cx.external_traits.borrow().contains_key(&did) || cx.active_extern_traits.contains(&did)
         {
             return;
         }
     }
 
     {
-        cx.active_extern_traits.borrow_mut().insert(did);
+        cx.active_extern_traits.insert(did);
     }
 
     debug!("record_extern_trait: {:?}", did);
     let trait_ = build_external_trait(cx, did);
 
     cx.external_traits.borrow_mut().insert(did, trait_);
-    cx.active_extern_traits.borrow_mut().remove(&did);
+    cx.active_extern_traits.remove(&did);
 }

src/librustdoc/clean/mod.rs

@@ -357,7 +357,7 @@ impl Clean<Lifetime> for hir::Lifetime {
                 | rl::Region::LateBound(_, node_id, _)
                 | rl::Region::Free(_, node_id),
             ) => {
-                if let Some(lt) = cx.lt_substs.borrow().get(&node_id).cloned() {
+                if let Some(lt) = cx.lt_substs.get(&node_id).cloned() {
                     return lt;
                 }
             }
@@ -644,7 +644,7 @@ impl Clean<Generics> for hir::Generics<'_> {
                 match param.kind {
                     GenericParamDefKind::Lifetime => unreachable!(),
                     GenericParamDefKind::Type { did, ref bounds, .. } => {
-                        cx.impl_trait_bounds.borrow_mut().insert(did.into(), bounds.clone());
+                        cx.impl_trait_bounds.insert(did.into(), bounds.clone());
                     }
                     GenericParamDefKind::Const { .. } => unreachable!(),
                 }
@@ -803,7 +803,7 @@ impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics, ty::GenericPredicates<'tcx
                 unreachable!();
             }
 
-            cx.impl_trait_bounds.borrow_mut().insert(param, bounds);
+            cx.impl_trait_bounds.insert(param, bounds);
         }
 
         // Now that `cx.impl_trait_bounds` is populated, we can process
@@ -1291,10 +1291,10 @@ fn clean_qpath(hir_ty: &hir::Ty<'_>, cx: &mut DocContext<'_>) -> Type {
     match qpath {
         hir::QPath::Resolved(None, ref path) => {
             if let Res::Def(DefKind::TyParam, did) = path.res {
-                if let Some(new_ty) = cx.ty_substs.borrow().get(&did).cloned() {
+                if let Some(new_ty) = cx.ty_substs.get(&did).cloned() {
                     return new_ty;
                 }
-                if let Some(bounds) = cx.impl_trait_bounds.borrow_mut().remove(&did.into()) {
+                if let Some(bounds) = cx.impl_trait_bounds.remove(&did.into()) {
                     return ImplTrait(bounds);
                 }
             }
@@ -1304,7 +1304,7 @@ fn clean_qpath(hir_ty: &hir::Ty<'_>, cx: &mut DocContext<'_>) -> Type {
                 // Substitute private type aliases
                 if let Some(def_id) = def_id.as_local() {
                     let hir_id = cx.tcx.hir().local_def_id_to_hir_id(def_id);
-                    if !cx.renderinfo.borrow().access_levels.is_exported(def_id.to_def_id()) {
+                    if !cx.renderinfo.access_levels.is_exported(def_id.to_def_id()) {
                         alias = Some(&cx.tcx.hir().expect_item(hir_id).kind);
                     }
                 }
@@ -1651,7 +1651,7 @@ impl<'tcx> Clean<Type> for Ty<'tcx> {
             ty::Projection(ref data) => data.clean(cx),
 
             ty::Param(ref p) => {
-                if let Some(bounds) = cx.impl_trait_bounds.borrow_mut().remove(&p.index.into()) {
+                if let Some(bounds) = cx.impl_trait_bounds.remove(&p.index.into()) {
                     ImplTrait(bounds)
                 } else {
                     Generic(p.name)

src/librustdoc/clean/utils.rs

@@ -23,10 +23,9 @@ crate fn krate(mut cx: &mut DocContext<'_>) -> Crate {
     let krate = cx.tcx.hir().krate();
     let module = crate::visit_ast::RustdocVisitor::new(&mut cx).visit(krate);
 
-    let mut r = cx.renderinfo.get_mut();
-    r.deref_trait_did = cx.tcx.lang_items().deref_trait();
-    r.deref_mut_trait_did = cx.tcx.lang_items().deref_mut_trait();
-    r.owned_box_did = cx.tcx.lang_items().owned_box();
+    cx.renderinfo.deref_trait_did = cx.tcx.lang_items().deref_trait();
+    cx.renderinfo.deref_mut_trait_did = cx.tcx.lang_items().deref_mut_trait();
+    cx.renderinfo.owned_box_did = cx.tcx.lang_items().owned_box();
 
     let mut externs = Vec::new();
     for &cnum in cx.tcx.crates().iter() {
@@ -494,10 +493,10 @@ crate fn enter_impl_trait<F, R>(cx: &mut DocContext<'_>, f: F) -> R
 where
     F: FnOnce(&mut DocContext<'_>) -> R,
 {
-    let old_bounds = mem::take(&mut *cx.impl_trait_bounds.get_mut());
+    let old_bounds = mem::take(&mut cx.impl_trait_bounds);
     let r = f(cx);
-    assert!(cx.impl_trait_bounds.borrow().is_empty());
-    *cx.impl_trait_bounds.get_mut() = old_bounds;
+    assert!(cx.impl_trait_bounds.is_empty());
+    cx.impl_trait_bounds = old_bounds;
     r
 }
 

src/librustdoc/core.rs

@@ -42,32 +42,37 @@ crate type ExternalPaths = FxHashMap<DefId, (Vec<String>, clean::TypeKind)>;
 
 crate struct DocContext<'tcx> {
     crate tcx: TyCtxt<'tcx>,
+    /// Name resolver. Used for intra-doc links.
+    ///
+    /// The `Rc<RefCell<...>>` wrapping is needed because that is what's returned by
+    /// [`Queries::expansion()`].
+    // FIXME: see if we can get rid of this RefCell somehow
     crate resolver: Rc<RefCell<interface::BoxedResolver>>,
     /// Used for normalization.
     ///
     /// Most of this logic is copied from rustc_lint::late.
     crate param_env: ParamEnv<'tcx>,
     /// Later on moved into `cache`
-    crate renderinfo: RefCell<RenderInfo>,
+    crate renderinfo: RenderInfo,
     /// Later on moved through `clean::Crate` into `cache`
     crate external_traits: Rc<RefCell<FxHashMap<DefId, clean::Trait>>>,
     /// Used while populating `external_traits` to ensure we don't process the same trait twice at
     /// the same time.
-    crate active_extern_traits: RefCell<FxHashSet<DefId>>,
+    crate active_extern_traits: FxHashSet<DefId>,
     // The current set of type and lifetime substitutions,
     // for expanding type aliases at the HIR level:
     /// Table `DefId` of type parameter -> substituted type
-    crate ty_substs: RefCell<FxHashMap<DefId, clean::Type>>,
+    crate ty_substs: FxHashMap<DefId, clean::Type>,
     /// Table `DefId` of lifetime parameter -> substituted lifetime
-    crate lt_substs: RefCell<FxHashMap<DefId, clean::Lifetime>>,
+    crate lt_substs: FxHashMap<DefId, clean::Lifetime>,
     /// Table `DefId` of const parameter -> substituted const
-    crate ct_substs: RefCell<FxHashMap<DefId, clean::Constant>>,
+    crate ct_substs: FxHashMap<DefId, clean::Constant>,
     /// Table synthetic type parameter for `impl Trait` in argument position -> bounds
-    crate impl_trait_bounds: RefCell<FxHashMap<ImplTraitParam, Vec<clean::GenericBound>>>,
+    crate impl_trait_bounds: FxHashMap<ImplTraitParam, Vec<clean::GenericBound>>,
     crate fake_def_ids: FxHashMap<CrateNum, DefIndex>,
     /// Auto-trait or blanket impls processed so far, as `(self_ty, trait_def_id)`.
     // FIXME(eddyb) make this a `ty::TraitRef<'tcx>` set.
-    crate generated_synthetics: RefCell<FxHashSet<(Ty<'tcx>, DefId)>>,
+    crate generated_synthetics: FxHashSet<(Ty<'tcx>, DefId)>,
     crate auto_traits: Vec<DefId>,
     /// The options given to rustdoc that could be relevant to a pass.
     crate render_options: RenderOptions,
@@ -112,14 +117,14 @@ impl<'tcx> DocContext<'tcx> {
         F: FnOnce(&mut Self) -> R,
     {
         let (old_tys, old_lts, old_cts) = (
-            mem::replace(&mut *self.ty_substs.get_mut(), ty_substs),
-            mem::replace(&mut *self.lt_substs.get_mut(), lt_substs),
-            mem::replace(&mut *self.ct_substs.get_mut(), ct_substs),
+            mem::replace(&mut self.ty_substs, ty_substs),
+            mem::replace(&mut self.lt_substs, lt_substs),
+            mem::replace(&mut self.ct_substs, ct_substs),
         );
         let r = f(self);
-        *self.ty_substs.get_mut() = old_tys;
-        *self.lt_substs.get_mut() = old_lts;
-        *self.ct_substs.get_mut() = old_cts;
+        self.ty_substs = old_tys;
+        self.lt_substs = old_lts;
+        self.ct_substs = old_cts;
         r
     }
 
@@ -509,7 +514,7 @@ crate fn run_global_ctxt(
         param_env: ParamEnv::empty(),
         external_traits: Default::default(),
         active_extern_traits: Default::default(),
-        renderinfo: RefCell::new(renderinfo),
+        renderinfo,
         ty_substs: Default::default(),
         lt_substs: Default::default(),
         ct_substs: Default::default(),
@@ -642,7 +647,7 @@ crate fn run_global_ctxt(
     // The main crate doc comments are always collapsed.
     krate.collapsed = true;
 
-    (krate, ctxt.renderinfo.into_inner(), ctxt.render_options)
+    (krate, ctxt.renderinfo, ctxt.render_options)
 }
 
 /// Due to <https://github.com/rust-lang/rust/pull/73566>,

src/librustdoc/passes/calculate_doc_coverage.rs

@@ -127,7 +127,7 @@ impl<'a, 'b> CoverageCalculator<'a, 'b> {
     }
 
     fn print_results(&self) {
-        let output_format = self.ctx.renderinfo.borrow().output_format;
+        let output_format = self.ctx.renderinfo.output_format;
         if output_format.is_json() {
             println!("{}", self.to_json());
             return;

src/librustdoc/passes/collect_trait_impls.rs

@@ -48,11 +48,10 @@ crate fn collect_trait_impls(krate: Crate, cx: &mut DocContext<'_>) -> Crate {
                 if !cx.tcx.get_attrs(def_id).lists(sym::doc).has_word(sym::hidden) {
                     let self_ty = cx.tcx.type_of(def_id);
                     let impls = get_auto_trait_and_blanket_impls(cx, self_ty, def_id);
-                    let mut renderinfo = cx.renderinfo.borrow_mut();
 
-                    new_items.extend(impls.filter(|i| renderinfo.inlined.insert(i.def_id)));
+                    new_items.extend(impls.filter(|i| cx.renderinfo.inlined.insert(i.def_id)));
                 }
-            })
+            });
         }
     }
 

src/librustdoc/passes/doc_test_lints.rs

@@ -97,8 +97,7 @@ crate fn look_for_tests<'tcx>(cx: &DocContext<'tcx>, dox: &str, item: &Item) {
                 |lint| lint.build("missing code example in this documentation").emit(),
             );
         }
-    } else if tests.found_tests > 0 && !cx.renderinfo.borrow().access_levels.is_public(item.def_id)
-    {
+    } else if tests.found_tests > 0 && !cx.renderinfo.access_levels.is_public(item.def_id) {
         cx.tcx.struct_span_lint_hir(
             lint::builtin::PRIVATE_DOC_TESTS,
             hir_id,

src/librustdoc/passes/strip_private.rs

@@ -17,7 +17,7 @@ crate const STRIP_PRIVATE: Pass = Pass {
 crate fn strip_private(mut krate: clean::Crate, cx: &mut DocContext<'_>) -> clean::Crate {
     // This stripper collects all *retained* nodes.
     let mut retained = DefIdSet::default();
-    let access_levels = cx.renderinfo.borrow().access_levels.clone();
+    let access_levels = cx.renderinfo.access_levels.clone();
 
     // strip all private items
     {