Use () for lang items.

compiler/rustc_middle/src/query/mod.rs

@@ -1330,7 +1330,7 @@ rustc_queries! {
         desc { |tcx| "computing crate imported by `{}`", tcx.def_path_str(def_id.to_def_id()) }
     }
 
-    query get_lib_features(_: CrateNum) -> LibFeatures {
+    query get_lib_features(_: ()) -> LibFeatures {
         storage(ArenaCacheSelector<'tcx>)
         eval_always
         desc { "calculating the lib features map" }
@@ -1340,16 +1340,14 @@ rustc_queries! {
         desc { "calculating the lib features defined in a crate" }
     }
     /// Returns the lang items defined in another crate by loading it from metadata.
-    // FIXME: It is illegal to pass a `CrateNum` other than `LOCAL_CRATE` here, just get rid
-    // of that argument?
-    query get_lang_items(_: CrateNum) -> LanguageItems {
+    query get_lang_items(_: ()) -> LanguageItems {
         storage(ArenaCacheSelector<'tcx>)
         eval_always
         desc { "calculating the lang items map" }
     }
 
     /// Returns all diagnostic items defined in all crates.
-    query all_diagnostic_items(_: CrateNum) -> FxHashMap<Symbol, DefId> {
+    query all_diagnostic_items(_: ()) -> FxHashMap<Symbol, DefId> {
         storage(ArenaCacheSelector<'tcx>)
         eval_always
         desc { "calculating the diagnostic items map" }
@@ -1411,12 +1409,12 @@ rustc_queries! {
         desc { |tcx| "names_imported_by_glob_use for `{}`", tcx.def_path_str(def_id.to_def_id()) }
     }
 
-    query stability_index(_: CrateNum) -> stability::Index<'tcx> {
+    query stability_index(_: ()) -> stability::Index<'tcx> {
         storage(ArenaCacheSelector<'tcx>)
         eval_always
         desc { "calculating the stability index for the local crate" }
     }
-    query all_crate_nums(_: CrateNum) -> &'tcx [CrateNum] {
+    query all_crate_nums(_: ()) -> &'tcx [CrateNum] {
         eval_always
         desc { "fetching all foreign CrateNum instances" }
     }
@@ -1644,7 +1642,7 @@ rustc_queries! {
         desc { |tcx| "estimating size for `{}`", tcx.def_path_str(def.def_id()) }
     }
 
-    query features_query(_: CrateNum) -> &'tcx rustc_feature::Features {
+    query features_query(_: ()) -> &'tcx rustc_feature::Features {
         eval_always
         desc { "looking up enabled feature gates" }
     }

compiler/rustc_middle/src/ty/context.rs

@@ -1218,18 +1218,18 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn lib_features(self) -> &'tcx middle::lib_features::LibFeatures {
-        self.get_lib_features(LOCAL_CRATE)
+        self.get_lib_features(())
     }
 
     /// Obtain all lang items of this crate and all dependencies (recursively)
     pub fn lang_items(self) -> &'tcx rustc_hir::lang_items::LanguageItems {
-        self.get_lang_items(LOCAL_CRATE)
+        self.get_lang_items(())
     }
 
     /// Obtain the given diagnostic item's `DefId`. Use `is_diagnostic_item` if you just want to
     /// compare against another `DefId`, since `is_diagnostic_item` is cheaper.
     pub fn get_diagnostic_item(self, name: Symbol) -> Option<DefId> {
-        self.all_diagnostic_items(LOCAL_CRATE).get(&name).copied()
+        self.all_diagnostic_items(()).get(&name).copied()
     }
 
     /// Check whether the diagnostic item with the given `name` has the given `DefId`.
@@ -1238,11 +1238,11 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn stability(self) -> &'tcx stability::Index<'tcx> {
-        self.stability_index(LOCAL_CRATE)
+        self.stability_index(())
     }
 
     pub fn crates(self) -> &'tcx [CrateNum] {
-        self.all_crate_nums(LOCAL_CRATE)
+        self.all_crate_nums(())
     }
 
     pub fn allocator_kind(self) -> Option<AllocatorKind> {
@@ -1250,7 +1250,7 @@ impl<'tcx> TyCtxt<'tcx> {
     }
 
     pub fn features(self) -> &'tcx rustc_feature::Features {
-        self.features_query(LOCAL_CRATE)
+        self.features_query(())
     }
 
     pub fn def_key(self, id: DefId) -> rustc_hir::definitions::DefKey {
@@ -2815,18 +2815,12 @@ pub fn provide(providers: &mut ty::query::Providers) {
         tcx.stability().local_deprecation_entry(id)
     };
     providers.extern_mod_stmt_cnum = |tcx, id| tcx.extern_crate_map.get(&id).cloned();
-    providers.all_crate_nums = |tcx, cnum| {
-        assert_eq!(cnum, LOCAL_CRATE);
-        tcx.arena.alloc_slice(&tcx.cstore.crates_untracked())
-    };
+    providers.all_crate_nums = |tcx, ()| tcx.arena.alloc_slice(&tcx.cstore.crates_untracked());
     providers.output_filenames = |tcx, cnum| {
         assert_eq!(cnum, LOCAL_CRATE);
         tcx.output_filenames.clone()
     };
-    providers.features_query = |tcx, cnum| {
-        assert_eq!(cnum, LOCAL_CRATE);
-        tcx.sess.features_untracked()
-    };
+    providers.features_query = |tcx, ()| tcx.sess.features_untracked();
     providers.is_panic_runtime = |tcx, cnum| {
         assert_eq!(cnum, LOCAL_CRATE);
         tcx.sess.contains_name(tcx.hir().krate_attrs(), sym::panic_runtime)

compiler/rustc_middle/src/ty/query/on_disk_cache.rs

@@ -579,7 +579,7 @@ impl<'sess> OnDiskCache<'sess> {
     ) -> IndexVec<CrateNum, Option<CrateNum>> {
         tcx.dep_graph.with_ignore(|| {
             let current_cnums = tcx
-                .all_crate_nums(LOCAL_CRATE)
+                .all_crate_nums(())
                 .iter()
                 .map(|&cnum| {
                     let crate_name = tcx.original_crate_name(cnum).to_string();