From: Bastian Kauschke <bastian_kauschke@hotmail.de>
Date: Sat, 18 Jul 2020 17:22:12 +0000 (+0200)
Subject: add note to `opt_const_param_of`
X-Git-Url: https://git.lizzy.rs/?a=commitdiff_plain;h=e8d16fdf9f95e4110df53650779be842b6749f60;p=rust.git

add note to `opt_const_param_of`
---

diff --git a/src/librustc_middle/query/mod.rs b/src/librustc_middle/query/mod.rs
index 40ff25cf3b1..06136a82e7b 100644
--- a/src/librustc_middle/query/mod.rs
+++ b/src/librustc_middle/query/mod.rs
@@ -103,9 +103,13 @@ fn describe_as_module(def_id: LocalDefId, tcx: TyCtxt<'_>) -> String {
         /// // ^ While calling `opt_const_param_of` for other bodies returns `None`.
         /// }
         /// ```
+        // It looks like caching this query on disk actually slightly
+        // worsened performance in #74376.
+        //
+        // Once const generics are more prevalently used, we might want to
+        // consider only caching calls returning `Some`.
         query opt_const_param_of(key: LocalDefId) -> Option<DefId> {
             desc { |tcx| "computing the optional const parameter of `{}`", tcx.def_path_str(key.to_def_id()) }
-            // FIXME(#74113): consider storing this query on disk.
         }
 
         /// Records the type of every item.