rustdoc: Queryify is_notable_trait

This might help with rust-lang#102375.

Author: camelid

compiler/rustc_middle/src/query/mod.rs

@@ -1126,6 +1126,11 @@ rustc_queries! {
         desc { |tcx| "checking whether `{}` is `doc(hidden)`", tcx.def_path_str(def_id) }
     }
 
+    /// Determines whether an item is annotated with `doc(notable_trait)`.
+    query is_doc_notable_trait(def_id: DefId) -> bool {
+        desc { |tcx| "checking whether `{}` is `doc(notable_trait)`", tcx.def_path_str(def_id) }
+    }
+
     /// Returns the attributes on the item at `def_id`.
     ///
     /// Do not use this directly, use `tcx.get_attrs` instead.

compiler/rustc_middle/src/ty/util.rs

@@ -1289,12 +1289,24 @@ pub fn is_doc_hidden(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
         .any(|items| items.iter().any(|item| item.has_name(sym::hidden)))
 }
 
+/// Determines whether an item is annotated with `doc(notable_trait)`.
+pub fn is_doc_notable_trait(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
+    tcx.get_attrs(def_id, sym::doc)
+        .filter_map(|attr| attr.meta_item_list())
+        .any(|items| items.iter().any(|item| item.has_name(sym::notable_trait)))
+}
+
 /// Determines whether an item is an intrinsic by Abi.
 pub fn is_intrinsic(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
     matches!(tcx.fn_sig(def_id).abi(), Abi::RustIntrinsic | Abi::PlatformIntrinsic)
 }
 
 pub fn provide(providers: &mut ty::query::Providers) {
-    *providers =
-        ty::query::Providers { normalize_opaque_types, is_doc_hidden, is_intrinsic, ..*providers }
+    *providers = ty::query::Providers {
+        normalize_opaque_types,
+        is_doc_hidden,
+        is_doc_notable_trait,
+        is_intrinsic,
+        ..*providers
+    }
 }

src/librustdoc/clean/types.rs

@@ -37,7 +37,7 @@ use crate::clean::cfg::Cfg;
 use crate::clean::clean_visibility;
 use crate::clean::external_path;
 use crate::clean::inline::{self, print_inlined_const};
-use crate::clean::utils::{has_doc_flag, is_literal_expr, print_const_expr, print_evaluated_const};
+use crate::clean::utils::{is_literal_expr, print_const_expr, print_evaluated_const};
 use crate::core::DocContext;
 use crate::formats::cache::Cache;
 use crate::formats::item_type::ItemType;
@@ -1524,7 +1524,7 @@ impl Trait {
         tcx.trait_is_auto(self.def_id)
     }
     pub(crate) fn is_notable_trait(&self, tcx: TyCtxt<'_>) -> bool {
-        has_doc_flag(tcx, self.def_id, sym::notable_trait)
+        tcx.is_doc_notable_trait(self.def_id)
     }
     pub(crate) fn unsafety(&self, tcx: TyCtxt<'_>) -> hir::Unsafety {
         tcx.trait_def(self.def_id).unsafety