Auto merge of #107303 - compiler-errors:intern-canonical-var-values, r=lcnr

Intern `CanonicalVarValues`

So that they are copy :sparkles:

3 files changed, 15 insertions, 18 deletions

diff --git a/compiler/rustc_infer/src/infer/canonical/mod.rs b/compiler/rustc_infer/src/infer/canonical/mod.rs
index e59715b706b..f7e3e4a1cc0 100644
--- a/compiler/rustc_infer/src/infer/canonical/mod.rs
+++ b/compiler/rustc_infer/src/infer/canonical/mod.rs
@@ -26,7 +26,7 @@ use crate::infer::{InferCtxt, RegionVariableOrigin, TypeVariableOrigin, TypeVari
 use rustc_index::vec::IndexVec;
 use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::subst::GenericArg;
-use rustc_middle::ty::{self, BoundVar, List};
+use rustc_middle::ty::{self, List};
 use rustc_span::source_map::Span;
 
 pub use rustc_middle::infer::canonical::*;
@@ -87,12 +87,13 @@ impl<'tcx> InferCtxt<'tcx> {
         variables: &List<CanonicalVarInfo<'tcx>>,
         universe_map: impl Fn(ty::UniverseIndex) -> ty::UniverseIndex,
     ) -> CanonicalVarValues<'tcx> {
-        let var_values: IndexVec<BoundVar, GenericArg<'tcx>> = variables
-            .iter()
-            .map(|info| self.instantiate_canonical_var(span, info, &universe_map))
-            .collect();
-
-        CanonicalVarValues { var_values }
+        CanonicalVarValues {
+            var_values: self.tcx.mk_substs(
+                variables
+                    .iter()
+                    .map(|info| self.instantiate_canonical_var(span, info, &universe_map)),
+            ),
+        }
     }
 
     /// Given the "info" about a canonical variable, creates a fresh
diff --git a/compiler/rustc_infer/src/infer/canonical/query_response.rs b/compiler/rustc_infer/src/infer/canonical/query_response.rs
index 9174bd524be..3e8e7734a5a 100644
--- a/compiler/rustc_infer/src/infer/canonical/query_response.rs
+++ b/compiler/rustc_infer/src/infer/canonical/query_response.rs
@@ -482,11 +482,8 @@ impl<'tcx> InferCtxt<'tcx> {
         // given variable in the loop above, use that. Otherwise, use
         // a fresh inference variable.
         let result_subst = CanonicalVarValues {
-            var_values: query_response
-                .variables
-                .iter()
-                .enumerate()
-                .map(|(index, info)| {
+            var_values: self.tcx.mk_substs(query_response.variables.iter().enumerate().map(
+                |(index, info)| {
                     if info.is_existential() {
                         match opt_values[BoundVar::new(index)] {
                             Some(k) => k,
@@ -499,8 +496,8 @@ impl<'tcx> InferCtxt<'tcx> {
                             universe_map[u.as_usize()]
                         })
                     }
-                })
-                .collect(),
+                },
+            )),
         };
 
         let mut obligations = vec![];
diff --git a/compiler/rustc_infer/src/infer/canonical/substitute.rs b/compiler/rustc_infer/src/infer/canonical/substitute.rs
index 389afe22eb7..e77f2d37b7d 100644
--- a/compiler/rustc_infer/src/infer/canonical/substitute.rs
+++ b/compiler/rustc_infer/src/infer/canonical/substitute.rs
@@ -72,16 +72,15 @@ where
         value
     } else {
         let delegate = FnMutDelegate {
-            regions: &mut |br: ty::BoundRegion| match var_values.var_values[br.var].unpack() {
+            regions: &mut |br: ty::BoundRegion| match var_values[br.var].unpack() {
                 GenericArgKind::Lifetime(l) => l,
                 r => bug!("{:?} is a region but value is {:?}", br, r),
             },
-            types: &mut |bound_ty: ty::BoundTy| match var_values.var_values[bound_ty.var].unpack() {
+            types: &mut |bound_ty: ty::BoundTy| match var_values[bound_ty.var].unpack() {
                 GenericArgKind::Type(ty) => ty,
                 r => bug!("{:?} is a type but value is {:?}", bound_ty, r),
             },
-            consts: &mut |bound_ct: ty::BoundVar, _| match var_values.var_values[bound_ct].unpack()
-            {
+            consts: &mut |bound_ct: ty::BoundVar, _| match var_values[bound_ct].unpack() {
                 GenericArgKind::Const(ct) => ct,
                 c => bug!("{:?} is a const but value is {:?}", bound_ct, c),
             },