Use () for lint_levels.

Author: cjgillot

compiler/rustc_lint/src/levels.rs

@@ -6,8 +6,7 @@ use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{struct_span_err, Applicability, DiagnosticBuilder};
 use rustc_hir as hir;
-use rustc_hir::def_id::{CrateNum, DefId, CRATE_DEF_INDEX, LOCAL_CRATE};
-use rustc_hir::{intravisit, HirId};
+use rustc_hir::{intravisit, HirId, CRATE_HIR_ID};
 use rustc_middle::hir::map::Map;
 use rustc_middle::lint::LevelAndSource;
 use rustc_middle::lint::LintDiagnosticBuilder;
@@ -28,10 +27,9 @@ use tracing::debug;
 
 use std::cmp;
 
-fn lint_levels(tcx: TyCtxt<'_>, cnum: CrateNum) -> LintLevelMap {
-    assert_eq!(cnum, LOCAL_CRATE);
+fn lint_levels(tcx: TyCtxt<'_>, (): ()) -> LintLevelMap {
     let store = unerased_lint_store(tcx);
-    let crate_attrs = tcx.get_attrs(DefId { krate: cnum, index: CRATE_DEF_INDEX });
+    let crate_attrs = tcx.hir().attrs(CRATE_HIR_ID);
     let levels = LintLevelsBuilder::new(tcx.sess, false, &store, crate_attrs);
     let mut builder = LintLevelMapBuilder { levels, tcx, store };
     let krate = tcx.hir().krate();

compiler/rustc_middle/src/query/mod.rs

@@ -199,7 +199,7 @@ rustc_queries! {
         desc { "looking up the native libraries of a linked crate" }
     }
 
-    query lint_levels(_: CrateNum) -> LintLevelMap {
+    query lint_levels(_: ()) -> LintLevelMap {
         storage(ArenaCacheSelector<'tcx>)
         eval_always
         desc { "computing the lint levels for items in this crate" }

compiler/rustc_middle/src/ty/context.rs

@@ -2623,7 +2623,7 @@ impl<'tcx> TyCtxt<'tcx> {
         lint: &'static Lint,
         mut id: hir::HirId,
     ) -> (Level, LintLevelSource) {
-        let sets = self.lint_levels(LOCAL_CRATE);
+        let sets = self.lint_levels(());
         loop {
             if let Some(pair) = sets.level_and_source(lint, id, self.sess) {
                 return pair;