Rename Resolver::active_features.

For the reasons described in the previous commit.

compiler/rustc_resolve/src/lib.rs

@@ -1074,8 +1074,8 @@ pub struct Resolver<'a, 'tcx> {
     /// Also includes of list of each fields visibility
     struct_constructors: LocalDefIdMap<(Res, ty::Visibility<DefId>, Vec<ty::Visibility<DefId>>)>,
 
-    /// Features enabled for this crate.
-    active_features: FxHashSet<Symbol>,
+    /// Features declared for this crate.
+    declared_features: FxHashSet<Symbol>,
 
     lint_buffer: LintBuffer,
 
@@ -1417,12 +1417,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
             multi_segment_macro_resolutions: Default::default(),
             builtin_attrs: Default::default(),
             containers_deriving_copy: Default::default(),
-            active_features: features
-                .declared_lib_features
-                .iter()
-                .map(|(feat, ..)| *feat)
-                .chain(features.declared_lang_features.iter().map(|(feat, ..)| *feat))
-                .collect(),
+            declared_features: features.declared_features.clone(),
             lint_buffer: LintBuffer::default(),
             next_node_id: CRATE_NODE_ID,
             node_id_to_def_id,

compiler/rustc_resolve/src/macros.rs

@@ -854,7 +854,7 @@ impl<'a, 'tcx> Resolver<'a, 'tcx> {
                 let feature = stability.feature;
 
                 let is_allowed = |feature| {
-                    self.active_features.contains(&feature) || span.allows_unstable(feature)
+                    self.declared_features.contains(&feature) || span.allows_unstable(feature)
                 };
                 let allowed_by_implication = implied_by.is_some_and(|feature| is_allowed(feature));
                 if !is_allowed(feature) && !allowed_by_implication {