From f4fd8a063369bbadc99cffb0a646deb96c0db151 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jana=20D=C3=B6nszelmann?= <jana@donsz.nl>
Date: Mon, 3 Nov 2025 16:06:58 +0100
Subject: [PATCH] experiment query caching

---
 compiler/rustc_middle/src/query/mod.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 9b4306f656d6..676f0d82e4fb 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -2759,9 +2759,10 @@ rustc_queries! {
     }
 
     /// Returns a list of all `externally implementable items` crate.
-    query externally_implementable_items(_: CrateNum) -> &'tcx FxIndexMap<DefId, (EiiDecl, FxIndexMap<DefId, EiiImpl>)> {
+    query externally_implementable_items(cnum: CrateNum) -> &'tcx FxIndexMap<DefId, (EiiDecl, FxIndexMap<DefId, EiiImpl>)> {
         arena_cache
         desc { "looking up the externally implementable items of a crate" }
+        cache_on_disk_if { *cnum == LOCAL_CRATE }
         separate_provide_extern
     }
 }