Rollup merge of #74376 - lcnr:type-dependent-path-cleanup, r=eddyb

test caching opt_const_param_of on disc

Followup to #74113, implements parts of #74360

Tried caching `opt_const_param_of` on disk and adding an early exit if `tcx.dep_kind(def_id) != DefKind::AnonConst`.

Ended up causing a perf regression instead, so we just remove the FIXME and a short note to `opt_const_param_of`.

r? @eddyb

diff --git a/src/librustc_middle/query/mod.rs b/src/librustc_middle/query/mod.rs
index 4dd8723bd72a11d4dc4069e0c8036c41b472db8b..f479a030d6325fb2a7e18aaa876b117e90859f36 100644 (file)
--- 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.