typeck in parallel

compiler/rustc_hir_analysis/src/check_unused.rs

@@ -7,6 +7,10 @@ use rustc_session::lint;
 pub fn check_crate(tcx: TyCtxt<'_>) {
     let mut used_trait_imports: UnordSet<LocalDefId> = Default::default();
 
+    // FIXME: Use `tcx.hir().par_body_owners()` when we implement creating `DefId`s
+    // for anon constants during their parents' typeck.
+    // Doing so at current will produce queries cycle errors because it may typeck
+    // on anon constants directly.
     for item_def_id in tcx.hir().body_owners() {
         let imports = tcx.used_trait_imports(item_def_id);
         debug!("GatherVisitor: item_def_id={:?} with imports {:#?}", item_def_id, imports);