Don't use incremental disk-cache for query predicates_of

Zalathar · Zalathar · commit c7a48e8b87f2 · 2026-03-07T17:54:17.000+11:00
This query is a relatively modest wrapper around a few underlying queries that
are themselves cached to disk. Removing the additional layer of disk caching
appears to be a significant perf win.

This query also appears to be the only query that uses a crate-local
`cache_on_disk_if` condition, without also using the `separate_provide_extern`
modifier.
diff --git a/compiler/rustc_middle/src/queries.rs b/compiler/rustc_middle/src/queries.rs
@@ -455,7 +455,6 @@ rustc_queries! {
     /// the result of this query for use in UI tests or for debugging purposes.
     query predicates_of(key: DefId) -> ty::GenericPredicates<'tcx> {
         desc { "computing predicates of `{}`", tcx.def_path_str(key) }
-        cache_on_disk_if { key.is_local() }
     }
 
     query opaque_types_defined_by(

Original file line number	Diff line number	Diff line change
`@@ -455,7 +455,6 @@ rustc_queries! {`
`455`	`455`	`/// the result of this query for use in UI tests or for debugging purposes.`
`456`	`456`	`query predicates_of(key: DefId) -> ty::GenericPredicates<'tcx> {`
`457`	`457`	desc { "computing predicates of `{}`", tcx.def_path_str(key) }
`458`		`- cache_on_disk_if { key.is_local() }`
`459`	`458`	`}`
`460`	`459`
`461`	`460`	`query opaque_types_defined_by(`