Use #![feature(adt_const_params)] for static query flags

compiler/rustc_query_impl/src/lib.rs

@@ -2,10 +2,13 @@
 
 // tidy-alphabetical-start
 #![allow(internal_features)]
+#![feature(adt_const_params)]
 #![feature(min_specialization)]
 #![feature(rustc_attrs)]
 // tidy-alphabetical-end
 
+use std::marker::ConstParamTy;
+
 use rustc_data_structures::stable_hasher::HashStable;
 use rustc_data_structures::sync::AtomicU64;
 use rustc_middle::arena::Arena;
@@ -35,29 +38,34 @@ pub use crate::plumbing::{QueryCtxt, query_key_hash_verify_all};
 mod profiling_support;
 pub use self::profiling_support::alloc_self_profile_query_strings;
 
+#[derive(ConstParamTy)] // Allow this struct to be used for const-generic values.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+struct QueryFlags {
+    /// True if this query has the `anon` modifier.
+    is_anon: bool,
+    /// True if this query has the `depth_limit` modifier.
+    is_depth_limit: bool,
+    /// True if this query has the `feedable` modifier.
+    is_feedable: bool,
+}
+
 /// Combines a [`QueryVTable`] with some additional compile-time booleans
 /// to implement [`QueryDispatcher`], for use by code in [`rustc_query_system`].
 ///
 /// Baking these boolean flags into the type gives a modest but measurable
 /// improvement to compiler perf and compiler code size; see
 /// <https://github.com/rust-lang/rust/pull/151633>.
-struct SemiDynamicQueryDispatcher<
-    'tcx,
-    C: QueryCache,
-    const ANON: bool,
-    const DEPTH_LIMIT: bool,
-    const FEEDABLE: bool,
-> {
+struct SemiDynamicQueryDispatcher<'tcx, C: QueryCache, const FLAGS: QueryFlags> {
     vtable: &'tcx QueryVTable<'tcx, C>,
 }
 
 // Manually implement Copy/Clone, because deriving would put trait bounds on the cache type.
-impl<'tcx, C: QueryCache, const ANON: bool, const DEPTH_LIMIT: bool, const FEEDABLE: bool> Copy
-    for SemiDynamicQueryDispatcher<'tcx, C, ANON, DEPTH_LIMIT, FEEDABLE>
+impl<'tcx, C: QueryCache, const FLAGS: QueryFlags> Copy
+    for SemiDynamicQueryDispatcher<'tcx, C, FLAGS>
 {
 }
-impl<'tcx, C: QueryCache, const ANON: bool, const DEPTH_LIMIT: bool, const FEEDABLE: bool> Clone
-    for SemiDynamicQueryDispatcher<'tcx, C, ANON, DEPTH_LIMIT, FEEDABLE>
+impl<'tcx, C: QueryCache, const FLAGS: QueryFlags> Clone
+    for SemiDynamicQueryDispatcher<'tcx, C, FLAGS>
 {
     fn clone(&self) -> Self {
         *self
@@ -65,8 +73,8 @@ impl<'tcx, C: QueryCache, const ANON: bool, const DEPTH_LIMIT: bool, const FEEDA
 }
 
 // This is `impl QueryDispatcher for SemiDynamicQueryDispatcher`.
-impl<'tcx, C: QueryCache, const ANON: bool, const DEPTH_LIMIT: bool, const FEEDABLE: bool>
-    QueryDispatcher<'tcx> for SemiDynamicQueryDispatcher<'tcx, C, ANON, DEPTH_LIMIT, FEEDABLE>
+impl<'tcx, C: QueryCache, const FLAGS: QueryFlags> QueryDispatcher<'tcx>
+    for SemiDynamicQueryDispatcher<'tcx, C, FLAGS>
 where
     for<'a> C::Key: HashStable<StableHashingContext<'a>>,
 {
@@ -158,7 +166,7 @@ where
 
     #[inline(always)]
     fn anon(self) -> bool {
-        ANON
+        FLAGS.is_anon
     }
 
     #[inline(always)]
@@ -168,12 +176,12 @@ where
 
     #[inline(always)]
     fn depth_limit(self) -> bool {
-        DEPTH_LIMIT
+        FLAGS.is_depth_limit
     }
 
     #[inline(always)]
     fn feedable(self) -> bool {
-        FEEDABLE
+        FLAGS.is_feedable
     }
 
     #[inline(always)]

compiler/rustc_query_impl/src/plumbing.rs

@@ -708,14 +708,18 @@ macro_rules! define_queries {
                 data: PhantomData<&'tcx ()>
             }
 
+            const FLAGS: QueryFlags = QueryFlags {
+                is_anon: is_anon!([$($modifiers)*]),
+                is_depth_limit: depth_limit!([$($modifiers)*]),
+                is_feedable: feedable!([$($modifiers)*]),
+            };
+
             impl<'tcx> QueryDispatcherUnerased<'tcx> for QueryType<'tcx> {
                 type UnerasedValue = queries::$name::Value<'tcx>;
                 type Dispatcher = SemiDynamicQueryDispatcher<
                     'tcx,
                     queries::$name::Storage<'tcx>,
-                    { is_anon!([$($modifiers)*]) },
-                    { depth_limit!([$($modifiers)*]) },
-                    { feedable!([$($modifiers)*]) },
+                    FLAGS,
                 >;
 
                 const NAME: &'static &'static str = &stringify!($name);