Auto merge of #102056 - b-naber:unevaluated, r=lcnr

Introduce mir::Unevaluated

Previously the distinction between unevaluated constants in the type-system and in mir was not explicit and a little confusing. Probably better to introduce its own type for that.

r? `@lcnr`

38 files changed, 220 insertions, 156 deletions

diff --git a/compiler/rustc_codegen_cranelift/src/constant.rs b/compiler/rustc_codegen_cranelift/src/constant.rs
index 6b4ed9b9d40..e12805b093c 100644
--- a/compiler/rustc_codegen_cranelift/src/constant.rs
+++ b/compiler/rustc_codegen_cranelift/src/constant.rs
@@ -5,7 +5,6 @@ use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
 use rustc_middle::mir::interpret::{
     read_target_uint, AllocId, ConstAllocation, ConstValue, ErrorHandled, GlobalAlloc, Scalar,
 };
-use rustc_middle::ty::ConstKind;
 use rustc_span::DUMMY_SP;
 
 use cranelift_codegen::ir::GlobalValueData;
@@ -42,15 +41,7 @@ pub(crate) fn check_constants(fx: &mut FunctionCx<'_, '_, '_>) -> bool {
     let mut all_constants_ok = true;
     for constant in &fx.mir.required_consts {
         let unevaluated = match fx.monomorphize(constant.literal) {
-            ConstantKind::Ty(ct) => match ct.kind() {
-                ConstKind::Unevaluated(uv) => uv.expand(),
-                ConstKind::Value(_) => continue,
-                ConstKind::Param(_)
-                | ConstKind::Infer(_)
-                | ConstKind::Bound(_, _)
-                | ConstKind::Placeholder(_)
-                | ConstKind::Error(_) => unreachable!("{:?}", ct),
-            },
+            ConstantKind::Ty(_) => unreachable!(),
             ConstantKind::Unevaluated(uv, _) => uv,
             ConstantKind::Val(..) => continue,
         };
@@ -118,7 +109,7 @@ pub(crate) fn codegen_constant<'tcx>(
 ) -> CValue<'tcx> {
     let (const_val, ty) = match fx.monomorphize(constant.literal) {
         ConstantKind::Ty(const_) => unreachable!("{:?}", const_),
-        ConstantKind::Unevaluated(ty::Unevaluated { def, substs, promoted }, ty)
+        ConstantKind::Unevaluated(mir::UnevaluatedConst { def, substs, promoted }, ty)
             if fx.tcx.is_static(def.did) =>
         {
             assert!(substs.is_empty());
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
index fb22befd0a4..60deb0abd34 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/qualifs.rs
@@ -5,6 +5,7 @@
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir::LangItem;
 use rustc_infer::infer::TyCtxtInferExt;
+use rustc_middle::mir;
 use rustc_middle::mir::*;
 use rustc_middle::ty::{self, subst::SubstsRef, AdtDef, Ty};
 use rustc_span::DUMMY_SP;
@@ -350,17 +351,13 @@ where
     // FIXME(valtrees): check whether const qualifs should behave the same
     // way for type and mir constants.
     let uneval = match constant.literal {
-        ConstantKind::Ty(ct) if matches!(ct.kind(), ty::ConstKind::Unevaluated(_)) => {
-            let ty::ConstKind::Unevaluated(uv) = ct.kind() else { unreachable!() };
-
-            Some(uv.expand())
-        }
-        ConstantKind::Ty(_) => None,
+        ConstantKind::Ty(ct) if matches!(ct.kind(), ty::ConstKind::Param(_)) => None,
+        ConstantKind::Ty(c) => bug!("expected ConstKind::Param here, found {:?}", c),
         ConstantKind::Unevaluated(uv, _) => Some(uv),
         ConstantKind::Val(..) => None,
     };
 
-    if let Some(ty::Unevaluated { def, substs: _, promoted }) = uneval {
+    if let Some(mir::UnevaluatedConst { def, substs: _, promoted }) = uneval {
         // Use qualifs of the type for the promoted. Promoteds in MIR body should be possible
         // only for `NeedsNonConstDrop` with precise drop checking. This is the only const
         // check performed after the promotion. Verify that with an assertion.
@@ -368,11 +365,8 @@ where
 
         // Don't peek inside trait associated constants.
         if promoted.is_none() && cx.tcx.trait_of_item(def.did).is_none() {
-            let qualifs = if let Some((did, param_did)) = def.as_const_arg() {
-                cx.tcx.at(constant.span).mir_const_qualif_const_arg((did, param_did))
-            } else {
-                cx.tcx.at(constant.span).mir_const_qualif(def.did)
-            };
+            assert_eq!(def.const_param_did, None, "expected associated const: {def:?}");
+            let qualifs = cx.tcx.at(constant.span).mir_const_qualif(def.did);
 
             if !Q::in_qualifs(&qualifs) {
                 return false;
diff --git a/compiler/rustc_const_eval/src/transform/promote_consts.rs b/compiler/rustc_const_eval/src/transform/promote_consts.rs
index 461051574e5..4b219300739 100644
--- a/compiler/rustc_const_eval/src/transform/promote_consts.rs
+++ b/compiler/rustc_const_eval/src/transform/promote_consts.rs
@@ -13,6 +13,7 @@
 //! move analysis runs after promotion on broken MIR.
 
 use rustc_hir as hir;
+use rustc_middle::mir;
 use rustc_middle::mir::traversal::ReversePostorderIter;
 use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor};
 use rustc_middle::mir::*;
@@ -840,7 +841,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                 promoted.span = span;
                 promoted.local_decls[RETURN_PLACE] = LocalDecl::new(ty, span);
                 let substs = tcx.erase_regions(InternalSubsts::identity_for_item(tcx, def.did));
-                let uneval = ty::Unevaluated { def, substs, promoted: Some(promoted_id) };
+                let uneval = mir::UnevaluatedConst { def, substs, promoted: Some(promoted_id) };
 
                 Operand::Constant(Box::new(Constant {
                     span,
diff --git a/compiler/rustc_infer/src/infer/combine.rs b/compiler/rustc_infer/src/infer/combine.rs
index 682ad02da86..9488f1f6bfc 100644
--- a/compiler/rustc_infer/src/infer/combine.rs
+++ b/compiler/rustc_infer/src/infer/combine.rs
@@ -734,9 +734,7 @@ impl<'tcx> TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
                     }
                 }
             }
-            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => {
-                assert_eq!(promoted, ());
-
+            ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }) => {
                 let substs = self.relate_with_variance(
                     ty::Variance::Invariant,
                     ty::VarianceDiagInfo::default(),
@@ -745,7 +743,7 @@ impl<'tcx> TypeRelation<'tcx> for Generalizer<'_, 'tcx> {
                 )?;
                 Ok(self.tcx().mk_const(ty::ConstS {
                     ty: c.ty(),
-                    kind: ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }),
+                    kind: ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }),
                 }))
             }
             _ => relate::super_relate_consts(self, c, c),
@@ -949,9 +947,7 @@ impl<'tcx> TypeRelation<'tcx> for ConstInferUnifier<'_, 'tcx> {
                     }
                 }
             }
-            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => {
-                assert_eq!(promoted, ());
-
+            ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }) => {
                 let substs = self.relate_with_variance(
                     ty::Variance::Invariant,
                     ty::VarianceDiagInfo::default(),
@@ -961,7 +957,7 @@ impl<'tcx> TypeRelation<'tcx> for ConstInferUnifier<'_, 'tcx> {
 
                 Ok(self.tcx().mk_const(ty::ConstS {
                     ty: c.ty(),
-                    kind: ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }),
+                    kind: ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }),
                 }))
             }
             _ => relate::super_relate_consts(self, c, c),
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs
index 3abed12217c..55cf9b7a2ea 100644
--- a/compiler/rustc_infer/src/infer/mod.rs
+++ b/compiler/rustc_infer/src/infer/mod.rs
@@ -705,8 +705,8 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     #[instrument(skip(self), level = "debug")]
     pub fn try_unify_abstract_consts(
         &self,
-        a: ty::Unevaluated<'tcx, ()>,
-        b: ty::Unevaluated<'tcx, ()>,
+        a: ty::UnevaluatedConst<'tcx>,
+        b: ty::UnevaluatedConst<'tcx>,
         param_env: ty::ParamEnv<'tcx>,
     ) -> bool {
         // Reject any attempt to unify two unevaluated constants that contain inference
@@ -1690,7 +1690,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn try_const_eval_resolve(
         &self,
         param_env: ty::ParamEnv<'tcx>,
-        unevaluated: ty::Unevaluated<'tcx, ()>,
+        unevaluated: ty::UnevaluatedConst<'tcx>,
         ty: Ty<'tcx>,
         span: Option<Span>,
     ) -> Result<ty::Const<'tcx>, ErrorHandled> {
@@ -1725,7 +1725,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn const_eval_resolve(
         &self,
         mut param_env: ty::ParamEnv<'tcx>,
-        unevaluated: ty::Unevaluated<'tcx, ()>,
+        unevaluated: ty::UnevaluatedConst<'tcx>,
         span: Option<Span>,
     ) -> EvalToValTreeResult<'tcx> {
         let mut substs = self.resolve_vars_if_possible(unevaluated.substs);
@@ -1756,8 +1756,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         debug!(?param_env_erased);
         debug!(?substs_erased);
 
-        let unevaluated =
-            ty::Unevaluated { def: unevaluated.def, substs: substs_erased, promoted: () };
+        let unevaluated = ty::UnevaluatedConst { def: unevaluated.def, substs: substs_erased };
 
         // The return value is the evaluated value which doesn't contain any reference to inference
         // variables, thus we don't need to substitute back the original values.
diff --git a/compiler/rustc_middle/src/mir/interpret/queries.rs b/compiler/rustc_middle/src/mir/interpret/queries.rs
index a8c7505329c..734c31192c7 100644
--- a/compiler/rustc_middle/src/mir/interpret/queries.rs
+++ b/compiler/rustc_middle/src/mir/interpret/queries.rs
@@ -36,7 +36,7 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn const_eval_resolve(
         self,
         param_env: ty::ParamEnv<'tcx>,
-        ct: ty::Unevaluated<'tcx>,
+        ct: mir::UnevaluatedConst<'tcx>,
         span: Option<Span>,
     ) -> EvalToConstValueResult<'tcx> {
         // Cannot resolve `Unevaluated` constants that contain inference
@@ -49,7 +49,11 @@ impl<'tcx> TyCtxt<'tcx> {
             bug!("did not expect inference variables here");
         }
 
-        match ty::Instance::resolve_opt_const_arg(self, param_env, ct.def, ct.substs) {
+        match ty::Instance::resolve_opt_const_arg(
+            self, param_env,
+            // FIXME: maybe have a seperate version for resolving mir::UnevaluatedConst?
+            ct.def, ct.substs,
+        ) {
             Ok(Some(instance)) => {
                 let cid = GlobalId { instance, promoted: ct.promoted };
                 self.const_eval_global_id(param_env, cid, span)
@@ -63,7 +67,7 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn const_eval_resolve_for_typeck(
         self,
         param_env: ty::ParamEnv<'tcx>,
-        ct: ty::Unevaluated<'tcx, ()>,
+        ct: ty::UnevaluatedConst<'tcx>,
         span: Option<Span>,
     ) -> EvalToValTreeResult<'tcx> {
         // Cannot resolve `Unevaluated` constants that contain inference
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index 86ffce8ceb4..78a16788815 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -2055,7 +2055,7 @@ pub enum ConstantKind<'tcx> {
     Ty(ty::Const<'tcx>),
 
     /// An unevaluated mir constant which is not part of the type system.
-    Unevaluated(ty::Unevaluated<'tcx, Option<Promoted>>, Ty<'tcx>),
+    Unevaluated(UnevaluatedConst<'tcx>, Ty<'tcx>),
 
     /// This constant cannot go back into the type system, as it represents
     /// something the type system cannot handle (e.g. pointers).
@@ -2315,12 +2315,11 @@ impl<'tcx> ConstantKind<'tcx> {
             ty::InlineConstSubsts::new(tcx, ty::InlineConstSubstsParts { parent_substs, ty })
                 .substs;
 
-        let uneval = ty::Unevaluated {
+        let uneval = UnevaluatedConst {
             def: ty::WithOptConstParam::unknown(def_id).to_global(),
             substs,
             promoted: None,
         };
-
         debug_assert!(!uneval.has_free_regions());
 
         Self::Unevaluated(uneval, ty)
@@ -2404,7 +2403,7 @@ impl<'tcx> ConstantKind<'tcx> {
 
         let hir_id = tcx.hir().local_def_id_to_hir_id(def.did);
         let span = tcx.hir().span(hir_id);
-        let uneval = ty::Unevaluated::new(def.to_global(), substs);
+        let uneval = UnevaluatedConst::new(def.to_global(), substs);
         debug!(?span, ?param_env);
 
         match tcx.const_eval_resolve(param_env, uneval, Some(span)) {
@@ -2417,7 +2416,7 @@ impl<'tcx> ConstantKind<'tcx> {
                 // Error was handled in `const_eval_resolve`. Here we just create a
                 // new unevaluated const and error hard later in codegen
                 Self::Unevaluated(
-                    ty::Unevaluated {
+                    UnevaluatedConst {
                         def: def.to_global(),
                         substs: InternalSubsts::identity_for_item(tcx, def.did.to_def_id()),
                         promoted: None,
@@ -2440,6 +2439,34 @@ impl<'tcx> ConstantKind<'tcx> {
     }
 }
 
+/// An unevaluated (potentially generic) constant used in MIR.
+#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable, Lift)]
+#[derive(Hash, HashStable)]
+pub struct UnevaluatedConst<'tcx> {
+    pub def: ty::WithOptConstParam<DefId>,
+    pub substs: SubstsRef<'tcx>,
+    pub promoted: Option<Promoted>,
+}
+
+impl<'tcx> UnevaluatedConst<'tcx> {
+    // FIXME: probably should get rid of this method. It's also wrong to
+    // shrink and then later expand a promoted.
+    #[inline]
+    pub fn shrink(self) -> ty::UnevaluatedConst<'tcx> {
+        ty::UnevaluatedConst { def: self.def, substs: self.substs }
+    }
+}
+
+impl<'tcx> UnevaluatedConst<'tcx> {
+    #[inline]
+    pub fn new(
+        def: ty::WithOptConstParam<DefId>,
+        substs: SubstsRef<'tcx>,
+    ) -> UnevaluatedConst<'tcx> {
+        UnevaluatedConst { def, substs, promoted: Default::default() }
+    }
+}
+
 /// A collection of projections into user types.
 ///
 /// They are projections because a binding can occur a part of a
diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs
index 0b42137d4e3..05dcfba77b2 100644
--- a/compiler/rustc_middle/src/mir/pretty.rs
+++ b/compiler/rustc_middle/src/mir/pretty.rs
@@ -466,10 +466,9 @@ impl<'tcx> Visitor<'tcx> for ExtraComments<'tcx> {
                     ty::ConstKind::Param(p) => format!("Param({})", p),
                     ty::ConstKind::Unevaluated(uv) => {
                         format!(
-                            "Unevaluated({}, {:?}, {:?})",
+                            "Unevaluated({}, {:?})",
                             self.tcx.def_path_str(uv.def.did),
                             uv.substs,
-                            uv.promoted,
                         )
                     }
                     ty::ConstKind::Value(val) => format!("Value({})", fmt_valtree(&val)),
diff --git a/compiler/rustc_middle/src/mir/type_foldable.rs b/compiler/rustc_middle/src/mir/type_foldable.rs
index 9d098c8083e..8e18cad442e 100644
--- a/compiler/rustc_middle/src/mir/type_foldable.rs
+++ b/compiler/rustc_middle/src/mir/type_foldable.rs
@@ -3,6 +3,7 @@
 use rustc_ast::InlineAsmTemplatePiece;
 
 use super::*;
+use crate::mir;
 use crate::ty;
 
 TrivialTypeTraversalAndLiftImpls! {
@@ -50,6 +51,25 @@ impl<'tcx, R: Idx, C: Idx> TypeFoldable<'tcx> for BitMatrix<R, C> {
     }
 }
 
+impl<'tcx> TypeFoldable<'tcx> for mir::UnevaluatedConst<'tcx> {
+    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
+        folder.try_fold_mir_unevaluated(self)
+    }
+}
+
+impl<'tcx> TypeSuperFoldable<'tcx> for mir::UnevaluatedConst<'tcx> {
+    fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
+        self,
+        folder: &mut F,
+    ) -> Result<Self, F::Error> {
+        Ok(mir::UnevaluatedConst {
+            def: self.def,
+            substs: self.substs.try_fold_with(folder)?,
+            promoted: self.promoted,
+        })
+    }
+}
+
 impl<'tcx> TypeFoldable<'tcx> for ConstantKind<'tcx> {
     #[inline(always)]
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
diff --git a/compiler/rustc_middle/src/mir/type_visitable.rs b/compiler/rustc_middle/src/mir/type_visitable.rs
index be19bb486d4..a136ca4d8c3 100644
--- a/compiler/rustc_middle/src/mir/type_visitable.rs
+++ b/compiler/rustc_middle/src/mir/type_visitable.rs
@@ -1,6 +1,7 @@
 //! `TypeVisitable` implementations for MIR types
 
 use super::*;
+use crate::mir;
 
 impl<'tcx, R: Idx, C: Idx> TypeVisitable<'tcx> for BitMatrix<R, C> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> ControlFlow<V::BreakTy> {
@@ -8,6 +9,18 @@ impl<'tcx, R: Idx, C: Idx> TypeVisitable<'tcx> for BitMatrix<R, C> {
     }
 }
 
+impl<'tcx> TypeVisitable<'tcx> for mir::UnevaluatedConst<'tcx> {
+    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
+        visitor.visit_mir_unevaluated(*self)
+    }
+}
+
+impl<'tcx> TypeSuperVisitable<'tcx> for mir::UnevaluatedConst<'tcx> {
+    fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
+        self.substs.visit_with(visitor)
+    }
+}
+
 impl<'tcx> TypeVisitable<'tcx> for ConstantKind<'tcx> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
         visitor.visit_mir_const(*self)
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index 1afea4864b8..b4ae13edf08 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -381,7 +381,7 @@ rustc_queries! {
     }
 
     query try_unify_abstract_consts(key:
-        ty::ParamEnvAnd<'tcx, (ty::Unevaluated<'tcx, ()>, ty::Unevaluated<'tcx, ()>
+        ty::ParamEnvAnd<'tcx, (ty::UnevaluatedConst<'tcx>, ty::UnevaluatedConst<'tcx>
     )>) -> bool {
         desc {
             |tcx| "trying to unify the generic constants {} and {}",
diff --git a/compiler/rustc_middle/src/ty/abstract_const.rs b/compiler/rustc_middle/src/ty/abstract_const.rs
index 8e0a1f1f9ac..641e53f2a15 100644
--- a/compiler/rustc_middle/src/ty/abstract_const.rs
+++ b/compiler/rustc_middle/src/ty/abstract_const.rs
@@ -30,7 +30,7 @@ pub struct AbstractConst<'tcx> {
 impl<'tcx> AbstractConst<'tcx> {
     pub fn new(
         tcx: TyCtxt<'tcx>,
-        uv: ty::Unevaluated<'tcx, ()>,
+        uv: ty::UnevaluatedConst<'tcx>,
     ) -> Result<Option<AbstractConst<'tcx>>, ErrorGuaranteed> {
         let inner = tcx.thir_abstract_const_opt_const_arg(uv.def)?;
         debug!("AbstractConst::new({:?}) = {:?}", uv, inner);
diff --git a/compiler/rustc_middle/src/ty/consts.rs b/compiler/rustc_middle/src/ty/consts.rs
index 4bc821dcfa1..315e3794f15 100644
--- a/compiler/rustc_middle/src/ty/consts.rs
+++ b/compiler/rustc_middle/src/ty/consts.rs
@@ -78,10 +78,9 @@ impl<'tcx> Const<'tcx> {
         match Self::try_eval_lit_or_param(tcx, ty, expr) {
             Some(v) => v,
             None => tcx.mk_const(ty::ConstS {
-                kind: ty::ConstKind::Unevaluated(ty::Unevaluated {
+                kind: ty::ConstKind::Unevaluated(ty::UnevaluatedConst {
                     def: def.to_global(),
                     substs: InternalSubsts::identity_for_item(tcx, def.did.to_def_id()),
-                    promoted: (),
                 }),
                 ty,
             }),
diff --git a/compiler/rustc_middle/src/ty/consts/kind.rs b/compiler/rustc_middle/src/ty/consts/kind.rs
index 4550152804e..c444ec23563 100644
--- a/compiler/rustc_middle/src/ty/consts/kind.rs
+++ b/compiler/rustc_middle/src/ty/consts/kind.rs
@@ -1,7 +1,7 @@
 use std::convert::TryInto;
 
+use crate::mir;
 use crate::mir::interpret::{AllocId, ConstValue, Scalar};
-use crate::mir::Promoted;
 use crate::ty::subst::{InternalSubsts, SubstsRef};
 use crate::ty::ParamEnv;
 use crate::ty::{self, TyCtxt, TypeVisitable};
@@ -12,40 +12,34 @@ use rustc_target::abi::Size;
 
 use super::ScalarInt;
 
-/// An unevaluated, potentially generic, constant.
+/// An unevaluated (potentially generic) constant used in the type-system.
 #[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable, Lift)]
 #[derive(Hash, HashStable)]
-pub struct Unevaluated<'tcx, P = Option<Promoted>> {
+pub struct UnevaluatedConst<'tcx> {
     pub def: ty::WithOptConstParam<DefId>,
     pub substs: SubstsRef<'tcx>,
-    pub promoted: P,
 }
 
-impl rustc_errors::IntoDiagnosticArg for Unevaluated<'_> {
+impl rustc_errors::IntoDiagnosticArg for UnevaluatedConst<'_> {
     fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> {
         format!("{:?}", self).into_diagnostic_arg()
     }
 }
 
-impl<'tcx> Unevaluated<'tcx> {
+impl<'tcx> UnevaluatedConst<'tcx> {
     #[inline]
-    pub fn shrink(self) -> Unevaluated<'tcx, ()> {
-        debug_assert_eq!(self.promoted, None);
-        Unevaluated { def: self.def, substs: self.substs, promoted: () }
+    pub fn expand(self) -> mir::UnevaluatedConst<'tcx> {
+        mir::UnevaluatedConst { def: self.def, substs: self.substs, promoted: None }
     }
 }
 
-impl<'tcx> Unevaluated<'tcx, ()> {
+impl<'tcx> UnevaluatedConst<'tcx> {
     #[inline]
-    pub fn expand(self) -> Unevaluated<'tcx> {
-        Unevaluated { def: self.def, substs: self.substs, promoted: None }
-    }
-}
-
-impl<'tcx, P: Default> Unevaluated<'tcx, P> {
-    #[inline]
-    pub fn new(def: ty::WithOptConstParam<DefId>, substs: SubstsRef<'tcx>) -> Unevaluated<'tcx, P> {
-        Unevaluated { def, substs, promoted: Default::default() }
+    pub fn new(
+        def: ty::WithOptConstParam<DefId>,
+        substs: SubstsRef<'tcx>,
+    ) -> UnevaluatedConst<'tcx> {
+        UnevaluatedConst { def, substs }
     }
 }
 
@@ -67,7 +61,7 @@ pub enum ConstKind<'tcx> {
 
     /// Used in the HIR by using `Unevaluated` everywhere and later normalizing to one of the other
     /// variants when the code is monomorphic enough for that.
-    Unevaluated(Unevaluated<'tcx, ()>),
+    Unevaluated(UnevaluatedConst<'tcx>),
 
     /// Used to hold computed value.
     Value(ty::ValTree<'tcx>),
@@ -185,8 +179,6 @@ impl<'tcx> ConstKind<'tcx> {
         if let ConstKind::Unevaluated(unevaluated) = self {
             use crate::mir::interpret::ErrorHandled;
 
-            assert_eq!(unevaluated.promoted, ());
-
             // HACK(eddyb) this erases lifetimes even though `const_eval_resolve`
             // also does later, but we want to do it before checking for
             // inference variables.
@@ -204,10 +196,9 @@ impl<'tcx> ConstKind<'tcx> {
             // FIXME(eddyb, skinny121) pass `InferCtxt` into here when it's available, so that
             // we can call `infcx.const_eval_resolve` which handles inference variables.
             let param_env_and = if param_env_and.needs_infer() {
-                tcx.param_env(unevaluated.def.did).and(ty::Unevaluated {
+                tcx.param_env(unevaluated.def.did).and(ty::UnevaluatedConst {
                     def: unevaluated.def,
                     substs: InternalSubsts::identity_for_item(tcx, unevaluated.def.did),
-                    promoted: (),
                 })
             } else {
                 param_env_and
diff --git a/compiler/rustc_middle/src/ty/flags.rs b/compiler/rustc_middle/src/ty/flags.rs
index 98b8a7386fe..a6d0678e99d 100644
--- a/compiler/rustc_middle/src/ty/flags.rs
+++ b/compiler/rustc_middle/src/ty/flags.rs
@@ -34,7 +34,7 @@ impl FlagComputation {
         result.flags
     }
 
-    pub fn for_unevaluated_const(uv: ty::Unevaluated<'_>) -> TypeFlags {
+    pub fn for_unevaluated_const(uv: ty::UnevaluatedConst<'_>) -> TypeFlags {
         let mut result = FlagComputation::new();
         result.add_unevaluated_const(uv);
         result.flags
@@ -313,7 +313,7 @@ impl FlagComputation {
         }
     }
 
-    fn add_unevaluated_const<P>(&mut self, ct: ty::Unevaluated<'_, P>) {
+    fn add_unevaluated_const(&mut self, ct: ty::UnevaluatedConst<'_>) {
         self.add_substs(ct.substs);
         self.add_flags(TypeFlags::HAS_CT_PROJECTION);
     }
diff --git a/compiler/rustc_middle/src/ty/fold.rs b/compiler/rustc_middle/src/ty/fold.rs
index cac95e14a23..e4234442fae 100644
--- a/compiler/rustc_middle/src/ty/fold.rs
+++ b/compiler/rustc_middle/src/ty/fold.rs
@@ -128,7 +128,17 @@ pub trait TypeFolder<'tcx>: FallibleTypeFolder<'tcx, Error = !> {
         c.super_fold_with(self)
     }
 
-    fn fold_unevaluated(&mut self, uv: ty::Unevaluated<'tcx>) -> ty::Unevaluated<'tcx> {
+    fn fold_ty_unevaluated(
+        &mut self,
+        uv: ty::UnevaluatedConst<'tcx>,
+    ) -> ty::UnevaluatedConst<'tcx> {
+        uv.super_fold_with(self)
+    }
+
+    fn fold_mir_unevaluated(
+        &mut self,
+        uv: mir::UnevaluatedConst<'tcx>,
+    ) -> mir::UnevaluatedConst<'tcx> {
         uv.super_fold_with(self)
     }
 
@@ -172,10 +182,17 @@ pub trait FallibleTypeFolder<'tcx>: Sized {
         c.try_super_fold_with(self)
     }
 
-    fn try_fold_unevaluated(
+    fn try_fold_ty_unevaluated(
+        &mut self,
+        c: ty::UnevaluatedConst<'tcx>,
+    ) -> Result<ty::UnevaluatedConst<'tcx>, Self::Error> {
+        c.try_super_fold_with(self)
+    }
+
+    fn try_fold_mir_unevaluated(
         &mut self,
-        c: ty::Unevaluated<'tcx>,
-    ) -> Result<ty::Unevaluated<'tcx>, Self::Error> {
+        c: mir::UnevaluatedConst<'tcx>,
+    ) -> Result<mir::UnevaluatedConst<'tcx>, Self::Error> {
         c.try_super_fold_with(self)
     }
 
@@ -225,11 +242,18 @@ where
         Ok(self.fold_const(c))
     }
 
-    fn try_fold_unevaluated(
+    fn try_fold_ty_unevaluated(
+        &mut self,
+        c: ty::UnevaluatedConst<'tcx>,
+    ) -> Result<ty::UnevaluatedConst<'tcx>, !> {
+        Ok(self.fold_ty_unevaluated(c))
+    }
+
+    fn try_fold_mir_unevaluated(
         &mut self,
-        c: ty::Unevaluated<'tcx>,
-    ) -> Result<ty::Unevaluated<'tcx>, !> {
-        Ok(self.fold_unevaluated(c))
+        c: mir::UnevaluatedConst<'tcx>,
+    ) -> Result<mir::UnevaluatedConst<'tcx>, !> {
+        Ok(self.fold_mir_unevaluated(c))
     }
 
     fn try_fold_predicate(&mut self, p: ty::Predicate<'tcx>) -> Result<ty::Predicate<'tcx>, !> {
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 982aacc7686..63dd213a085 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -73,7 +73,7 @@ pub use self::closure::{
     CAPTURE_STRUCT_LOCAL,
 };
 pub use self::consts::{
-    Const, ConstInt, ConstKind, ConstS, InferConst, ScalarInt, Unevaluated, ValTree,
+    Const, ConstInt, ConstKind, ConstS, InferConst, ScalarInt, UnevaluatedConst, ValTree,
 };
 pub use self::context::{
     tls, CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations,
@@ -682,7 +682,7 @@ pub enum PredicateKind<'tcx> {
     Coerce(CoercePredicate<'tcx>),
 
     /// Constant initializer must evaluate successfully.
-    ConstEvaluatable(ty::Unevaluated<'tcx, ()>),
+    ConstEvaluatable(ty::UnevaluatedConst<'tcx>),
 
     /// Constants must be equal. The first component is the const that is expected.
     ConstEquate(Const<'tcx>, Const<'tcx>),
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index b6cd5396b1d..b76e8999808 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -1201,9 +1201,7 @@ pub trait PrettyPrinter<'tcx>:
         }
 
         match ct.kind() {
-            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => {
-                assert_eq!(promoted, ());
-
+            ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }) => {
                 match self.tcx().def_kind(def.did) {
                     DefKind::Static(..) | DefKind::Const | DefKind::AssocConst => {
                         p!(print_value_path(def.did, substs))
diff --git a/compiler/rustc_middle/src/ty/relate.rs b/compiler/rustc_middle/src/ty/relate.rs
index 0d97d4acdfc..cdb618e030a 100644
--- a/compiler/rustc_middle/src/ty/relate.rs
+++ b/compiler/rustc_middle/src/ty/relate.rs
@@ -621,11 +621,7 @@ pub fn super_relate_consts<'tcx, R: TypeRelation<'tcx>>(
         // While this is slightly incorrect, it shouldn't matter for `min_const_generics`
         // and is the better alternative to waiting until `generic_const_exprs` can
         // be stabilized.
-        (ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu))
-            if au.def == bu.def && au.promoted == bu.promoted =>
-        {
-            assert_eq!(au.promoted, ());
-
+        (ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu)) if au.def == bu.def => {
             let substs = relation.relate_with_variance(
                 ty::Variance::Invariant,
                 ty::VarianceDiagInfo::default(),
@@ -633,11 +629,7 @@ pub fn super_relate_consts<'tcx, R: TypeRelation<'tcx>>(
                 bu.substs,
             )?;
             return Ok(tcx.mk_const(ty::ConstS {
-                kind: ty::ConstKind::Unevaluated(ty::Unevaluated {
-                    def: au.def,
-                    substs,
-                    promoted: (),
-                }),
+                kind: ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def: au.def, substs }),
                 ty: a.ty(),
             }));
         }
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index 004fcffdc40..3b42f4b51fc 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -829,45 +829,29 @@ impl<'tcx> TypeVisitable<'tcx> for InferConst<'tcx> {
     }
 }
 
-impl<'tcx> TypeFoldable<'tcx> for ty::Unevaluated<'tcx> {
+impl<'tcx> TypeFoldable<'tcx> for ty::UnevaluatedConst<'tcx> {
     fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        folder.try_fold_unevaluated(self)
+        folder.try_fold_ty_unevaluated(self)
     }
 }
 
-impl<'tcx> TypeVisitable<'tcx> for ty::Unevaluated<'tcx> {
+impl<'tcx> TypeVisitable<'tcx> for ty::UnevaluatedConst<'tcx> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        visitor.visit_unevaluated(*self)
+        visitor.visit_ty_unevaluated(*self)
     }
 }
 
-impl<'tcx> TypeSuperFoldable<'tcx> for ty::Unevaluated<'tcx> {
+impl<'tcx> TypeSuperFoldable<'tcx> for ty::UnevaluatedConst<'tcx> {
     fn try_super_fold_with<F: FallibleTypeFolder<'tcx>>(
         self,
         folder: &mut F,
     ) -> Result<Self, F::Error> {
-        Ok(ty::Unevaluated {
-            def: self.def,
-            substs: self.substs.try_fold_with(folder)?,
-            promoted: self.promoted,
-        })
+        Ok(ty::UnevaluatedConst { def: self.def, substs: self.substs.try_fold_with(folder)? })
     }
 }
 
-impl<'tcx> TypeSuperVisitable<'tcx> for ty::Unevaluated<'tcx> {
+impl<'tcx> TypeSuperVisitable<'tcx> for ty::UnevaluatedConst<'tcx> {
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
         self.substs.visit_with(visitor)
     }
 }
-
-impl<'tcx> TypeFoldable<'tcx> for ty::Unevaluated<'tcx, ()> {
-    fn try_fold_with<F: FallibleTypeFolder<'tcx>>(self, folder: &mut F) -> Result<Self, F::Error> {
-        Ok(self.expand().try_fold_with(folder)?.shrink())
-    }
-}
-
-impl<'tcx> TypeVisitable<'tcx> for ty::Unevaluated<'tcx, ()> {
-    fn visit_with<V: TypeVisitor<'tcx>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        self.expand().visit_with(visitor)
-    }
-}
diff --git a/compiler/rustc_middle/src/ty/visit.rs b/compiler/rustc_middle/src/ty/visit.rs
index 5f8cb578202..9c3b6a794e1 100644
--- a/compiler/rustc_middle/src/ty/visit.rs
+++ b/compiler/rustc_middle/src/ty/visit.rs
@@ -199,7 +199,17 @@ pub trait TypeVisitor<'tcx>: Sized {
         c.super_visit_with(self)
     }
 
-    fn visit_unevaluated(&mut self, uv: ty::Unevaluated<'tcx>) -> ControlFlow<Self::BreakTy> {
+    fn visit_ty_unevaluated(
+        &mut self,
+        uv: ty::UnevaluatedConst<'tcx>,
+    ) -> ControlFlow<Self::BreakTy> {
+        uv.super_visit_with(self)
+    }
+
+    fn visit_mir_unevaluated(
+        &mut self,
+        uv: mir::UnevaluatedConst<'tcx>,
+    ) -> ControlFlow<Self::BreakTy> {
         uv.super_visit_with(self)
     }
 
@@ -597,7 +607,10 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
 
     #[inline]
     #[instrument(level = "trace", ret)]
-    fn visit_unevaluated(&mut self, uv: ty::Unevaluated<'tcx>) -> ControlFlow<Self::BreakTy> {
+    fn visit_ty_unevaluated(
+        &mut self,
+        uv: ty::UnevaluatedConst<'tcx>,
+    ) -> ControlFlow<Self::BreakTy> {
         let flags = FlagComputation::for_unevaluated_const(uv);
         trace!(r.flags=?flags);
         if flags.intersects(self.flags) {
@@ -607,6 +620,19 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
         }
     }
 
+    fn visit_mir_unevaluated(
+        &mut self,
+        uv: mir::UnevaluatedConst<'tcx>,
+    ) -> ControlFlow<Self::BreakTy> {
+        let flags = FlagComputation::for_unevaluated_const(uv.shrink());
+        trace!(r.flags=?flags);
+        if flags.intersects(self.flags) {
+            ControlFlow::Break(FoundFlags)
+        } else {
+            ControlFlow::CONTINUE
+        }
+    }
+
     #[inline]
     #[instrument(level = "trace", ret)]
     fn visit_predicate(&mut self, predicate: ty::Predicate<'tcx>) -> ControlFlow<Self::BreakTy> {
diff --git a/compiler/rustc_mir_build/src/build/expr/as_constant.rs b/compiler/rustc_mir_build/src/build/expr/as_constant.rs
index c9bec130cc8..37dc1ad9f0d 100644
--- a/compiler/rustc_mir_build/src/build/expr/as_constant.rs
+++ b/compiler/rustc_mir_build/src/build/expr/as_constant.rs
@@ -2,6 +2,7 @@
 
 use crate::build::{parse_float_into_constval, Builder};
 use rustc_ast as ast;
+use rustc_middle::mir;
 use rustc_middle::mir::interpret::{
     Allocation, ConstValue, LitToConstError, LitToConstInput, Scalar,
 };
@@ -66,7 +67,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                     })
                 });
 
-                let uneval = ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs);
+                let uneval =
+                    mir::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs);
                 let literal = ConstantKind::Unevaluated(uneval, ty);
 
                 Constant { user_ty, span, literal }
@@ -79,7 +81,8 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 Constant { user_ty: None, span, literal }
             }
             ExprKind::ConstBlock { did: def_id, substs } => {
-                let uneval = ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs);
+                let uneval =
+                    mir::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs);
                 let literal = ConstantKind::Unevaluated(uneval, ty);
 
                 Constant { user_ty: None, span, literal }
diff --git a/compiler/rustc_mir_transform/src/const_prop_lint.rs b/compiler/rustc_mir_transform/src/const_prop_lint.rs
index 2885f06b19c..973f55437ee 100644
--- a/compiler/rustc_mir_transform/src/const_prop_lint.rs
+++ b/compiler/rustc_mir_transform/src/const_prop_lint.rs
@@ -16,8 +16,8 @@ use rustc_index::bit_set::BitSet;
 use rustc_index::vec::IndexVec;
 use rustc_middle::mir::visit::Visitor;
 use rustc_middle::mir::{
-    AssertKind, BinOp, Body, Constant, ConstantKind, Local, LocalDecl, Location, Operand, Place,
-    Rvalue, SourceInfo, SourceScope, SourceScopeData, Statement, StatementKind, Terminator,
+    self, AssertKind, BinOp, Body, Constant, ConstantKind, Local, LocalDecl, Location, Operand,
+    Place, Rvalue, SourceInfo, SourceScope, SourceScopeData, Statement, StatementKind, Terminator,
     TerminatorKind, UnOp, RETURN_PLACE,
 };
 use rustc_middle::ty::layout::{LayoutError, LayoutOf, LayoutOfHelpers, TyAndLayout};
@@ -301,7 +301,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                     let lint_only = match c.literal {
                         ConstantKind::Ty(ct) => ct.needs_subst(),
                         ConstantKind::Unevaluated(
-                            ty::Unevaluated { def: _, substs: _, promoted: Some(_) },
+                            mir::UnevaluatedConst { def: _, substs: _, promoted: Some(_) },
                             _,
                         ) => {
                             // Promoteds must lint and not error as the user didn't ask for them
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index b60bd3cea23..852557ba796 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -605,7 +605,7 @@ impl<'tcx> Inliner<'tcx> {
                 caller_body.required_consts.extend(
                     callee_body.required_consts.iter().copied().filter(|&ct| match ct.literal {
                         ConstantKind::Ty(_) => {
-                            bug!("should never encounter ty::Unevaluated in `required_consts`")
+                            bug!("should never encounter ty::UnevaluatedConst in `required_consts`")
                         }
                         ConstantKind::Val(..) | ConstantKind::Unevaluated(..) => true,
                     }),
diff --git a/compiler/rustc_monomorphize/src/polymorphize.rs b/compiler/rustc_monomorphize/src/polymorphize.rs
index 71cab023215..b7e3ca571e1 100644
--- a/compiler/rustc_monomorphize/src/polymorphize.rs
+++ b/compiler/rustc_monomorphize/src/polymorphize.rs
@@ -8,6 +8,7 @@
 use rustc_hir::{def::DefKind, def_id::DefId, ConstContext};
 use rustc_index::bit_set::FiniteBitSet;
 use rustc_middle::mir::{
+    self,
     visit::{TyContext, Visitor},
     Constant, ConstantKind, Local, LocalDecl, Location,
 };
@@ -299,11 +300,9 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
                 self.unused_parameters.clear(param.index);
                 ControlFlow::CONTINUE
             }
-            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted })
+            ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs })
                 if matches!(self.tcx.def_kind(def.did), DefKind::AnonConst) =>
             {
-                assert_eq!(promoted, ());
-
                 self.visit_child_body(def.did, substs);
                 ControlFlow::CONTINUE
             }
@@ -318,7 +317,7 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
 
         match constant {
             ConstantKind::Ty(ct) => ct.visit_with(self),
-            ConstantKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted: Some(p) }, _)
+            ConstantKind::Unevaluated(mir::UnevaluatedConst { def, substs: _, promoted: Some(p) }, _)
                 // Avoid considering `T` unused when constants are of the form:
                 //   `<Self as Foo<T>>::foo::promoted[p]`
                 if self.def_id == def.did && !self.tcx.generics_of(def.did).has_self =>
diff --git a/compiler/rustc_query_impl/src/keys.rs b/compiler/rustc_query_impl/src/keys.rs
index 31de83ee141..f1c2d03b9be 100644
--- a/compiler/rustc_query_impl/src/keys.rs
+++ b/compiler/rustc_query_impl/src/keys.rs
@@ -276,7 +276,7 @@ impl<'tcx> Key for (DefId, SubstsRef<'tcx>) {
     }
 }
 
-impl<'tcx> Key for (ty::Unevaluated<'tcx, ()>, ty::Unevaluated<'tcx, ()>) {
+impl<'tcx> Key for (ty::UnevaluatedConst<'tcx>, ty::UnevaluatedConst<'tcx>) {
     #[inline(always)]
     fn query_crate_is_local(&self) -> bool {
         (self.0).def.did.krate == LOCAL_CRATE
diff --git a/compiler/rustc_trait_selection/src/errors.rs b/compiler/rustc_trait_selection/src/errors.rs
index 5e1b80eae39..61793468594 100644
--- a/compiler/rustc_trait_selection/src/errors.rs
+++ b/compiler/rustc_trait_selection/src/errors.rs
@@ -1,6 +1,6 @@
 use rustc_errors::{fluent, ErrorGuaranteed, Handler, IntoDiagnostic};
 use rustc_macros::Diagnostic;
-use rustc_middle::ty::{PolyTraitRef, Ty, Unevaluated};
+use rustc_middle::ty::{self, PolyTraitRef, Ty};
 use rustc_session::Limit;
 use rustc_span::{Span, Symbol};
 
@@ -18,7 +18,7 @@ pub struct DumpVTableEntries<'a> {
 pub struct UnableToConstructConstantValue<'a> {
     #[primary_span]
     pub span: Span,
-    pub unevaluated: Unevaluated<'a>,
+    pub unevaluated: ty::UnevaluatedConst<'a>,
 }
 
 #[derive(Diagnostic)]
diff --git a/compiler/rustc_trait_selection/src/traits/auto_trait.rs b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
index bcdfa4f12d3..6ed4f1b8c49 100644
--- a/compiler/rustc_trait_selection/src/traits/auto_trait.rs
+++ b/compiler/rustc_trait_selection/src/traits/auto_trait.rs
@@ -834,7 +834,7 @@ impl<'tcx> AutoTraitFinder<'tcx> {
                                     let reported =
                                         tcx.sess.emit_err(UnableToConstructConstantValue {
                                             span: tcx.def_span(def_id),
-                                            unevaluated: unevaluated.expand(),
+                                            unevaluated: unevaluated,
                                         });
                                     Err(ErrorHandled::Reported(reported))
                                 }
diff --git a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
index 5a213987e87..dc585fca34f 100644
--- a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
+++ b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
@@ -138,7 +138,7 @@ impl<'tcx> ConstUnifyCtxt<'tcx> {
 #[instrument(skip(tcx), level = "debug")]
 pub fn try_unify_abstract_consts<'tcx>(
     tcx: TyCtxt<'tcx>,
-    (a, b): (ty::Unevaluated<'tcx, ()>, ty::Unevaluated<'tcx, ()>),
+    (a, b): (ty::UnevaluatedConst<'tcx>, ty::UnevaluatedConst<'tcx>),
     param_env: ty::ParamEnv<'tcx>,
 ) -> bool {
     (|| {
@@ -161,7 +161,7 @@ pub fn try_unify_abstract_consts<'tcx>(
 #[instrument(skip(infcx), level = "debug")]
 pub fn is_const_evaluatable<'cx, 'tcx>(
     infcx: &InferCtxt<'cx, 'tcx>,
-    uv: ty::Unevaluated<'tcx, ()>,
+    uv: ty::UnevaluatedConst<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     span: Span,
 ) -> Result<(), NotConstEvaluatable> {
diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs
index a54b725753c..2773b61e9ba 100644
--- a/compiler/rustc_trait_selection/src/traits/object_safety.rs
+++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs
@@ -838,7 +838,10 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
             }
         }
 
-        fn visit_unevaluated(&mut self, uv: ty::Unevaluated<'tcx>) -> ControlFlow<Self::BreakTy> {
+        fn visit_ty_unevaluated(
+            &mut self,
+            uv: ty::UnevaluatedConst<'tcx>,
+        ) -> ControlFlow<Self::BreakTy> {
             // Constants can only influence object safety if they reference `Self`.
             // This is only possible for unevaluated constants, so we walk these here.
             //
@@ -852,7 +855,7 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
             // This shouldn't really matter though as we can't really use any
             // constants which are not considered const evaluatable.
             use rustc_middle::ty::abstract_const::Node;
-            if let Ok(Some(ct)) = AbstractConst::new(self.tcx, uv.shrink()) {
+            if let Ok(Some(ct)) = AbstractConst::new(self.tcx, uv) {
                 walk_abstract_const(self.tcx, ct, |node| match node.root(self.tcx) {
                     Node::Leaf(leaf) => self.visit_const(leaf),
                     Node::Cast(_, _, ty) => self.visit_ty(ty),
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index ed83847e880..07b65a9748d 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -2141,7 +2141,7 @@ fn confirm_impl_candidate<'cx, 'tcx>(
         let identity_substs =
             crate::traits::InternalSubsts::identity_for_item(tcx, assoc_ty.item.def_id);
         let did = ty::WithOptConstParam::unknown(assoc_ty.item.def_id);
-        let kind = ty::ConstKind::Unevaluated(ty::Unevaluated::new(did, identity_substs));
+        let kind = ty::ConstKind::Unevaluated(ty::UnevaluatedConst::new(did, identity_substs));
         ty.map_bound(|ty| tcx.mk_const(ty::ConstS { ty, kind }).into())
     } else {
         ty.map_bound(|ty| ty.into())
diff --git a/compiler/rustc_ty_utils/src/consts.rs b/compiler/rustc_ty_utils/src/consts.rs
index 44c4fc48d3f..493ef335113 100644
--- a/compiler/rustc_ty_utils/src/consts.rs
+++ b/compiler/rustc_ty_utils/src/consts.rs
@@ -258,7 +258,8 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
                 self.nodes.push(Node::Leaf(ty::Const::from_value(self.tcx, val, node.ty)))
             }
             &ExprKind::NamedConst { def_id, substs, user_ty: _ } => {
-                let uneval = ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs);
+                let uneval =
+                    ty::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs);
 
                 let constant = self
                     .tcx
diff --git a/compiler/rustc_typeck/src/check/wfcheck.rs b/compiler/rustc_typeck/src/check/wfcheck.rs
index fd5df0d9fa1..e4124185d15 100644
--- a/compiler/rustc_typeck/src/check/wfcheck.rs
+++ b/compiler/rustc_typeck/src/check/wfcheck.rs
@@ -1113,10 +1113,12 @@ fn check_type_defn<'tcx, F>(
                 wfcx.register_obligation(traits::Obligation::new(
                     cause,
                     wfcx.param_env,
-                    ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(ty::Unevaluated::new(
-                        ty::WithOptConstParam::unknown(discr_def_id.to_def_id()),
-                        discr_substs,
-                    )))
+                    ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(
+                        ty::UnevaluatedConst::new(
+                            ty::WithOptConstParam::unknown(discr_def_id.to_def_id()),
+                            discr_substs,
+                        ),
+                    ))
                     .to_predicate(tcx),
                 ));
             }
diff --git a/compiler/rustc_typeck/src/collect.rs b/compiler/rustc_typeck/src/collect.rs
index afc8a9600ad..359a79e9979 100644
--- a/compiler/rustc_typeck/src/collect.rs
+++ b/compiler/rustc_typeck/src/collect.rs
@@ -2393,7 +2393,6 @@ fn const_evaluatable_predicates_of<'tcx>(
             let def_id = self.tcx.hir().local_def_id(c.hir_id);
             let ct = ty::Const::from_anon_const(self.tcx, def_id);
             if let ty::ConstKind::Unevaluated(uv) = ct.kind() {
-                assert_eq!(uv.promoted, ());
                 let span = self.tcx.hir().span(c.hir_id);
                 self.preds.insert((
                     ty::Binder::dummy(ty::PredicateKind::ConstEvaluatable(uv))
diff --git a/src/librustdoc/clean/utils.rs b/src/librustdoc/clean/utils.rs
index 3eaedaf1083..edcd81061f8 100644
--- a/src/librustdoc/clean/utils.rs
+++ b/src/librustdoc/clean/utils.rs
@@ -234,8 +234,7 @@ pub(crate) fn name_from_pat(p: &hir::Pat<'_>) -> Symbol {
 
 pub(crate) fn print_const(cx: &DocContext<'_>, n: ty::Const<'_>) -> String {
     match n.kind() {
-        ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted }) => {
-            assert_eq!(promoted, ());
+        ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs: _ }) => {
             let s = if let Some(def) = def.as_local() {
                 print_const_expr(cx.tcx, cx.tcx.hir().body_owned_by(def.did))
             } else {
diff --git a/src/test/mir-opt/issue_99325.main.mir_map.0.mir b/src/test/mir-opt/issue_99325.main.mir_map.0.mir
index 8659ddfdb00..35ad0df69c0 100644
--- a/src/test/mir-opt/issue_99325.main.mir_map.0.mir
+++ b/src/test/mir-opt/issue_99325.main.mir_map.0.mir
@@ -2,7 +2,7 @@
 
 | User Type Annotations
 | 0: user_ty: Canonical { max_universe: U0, variables: [], value: TypeOf(DefId(0:3 ~ issue_99325[8f58]::function_with_bytes), UserSubsts { substs: [Const { ty: &'static [u8; 4], kind: Value(Branch([Leaf(0x41), Leaf(0x41), Leaf(0x41), Leaf(0x41)])) }], user_self_ty: None }) }, span: $DIR/issue-99325.rs:10:16: 10:46, inferred_ty: fn() -> &'static [u8] {function_with_bytes::<&*b"AAAA">}
-| 1: user_ty: Canonical { max_universe: U0, variables: [], value: TypeOf(DefId(0:3 ~ issue_99325[8f58]::function_with_bytes), UserSubsts { substs: [Const { ty: &'static [u8; 4], kind: Unevaluated(Unevaluated { def: WithOptConstParam { did: DefId(0:8 ~ issue_99325[8f58]::main::{constant#1}), const_param_did: Some(DefId(0:4 ~ issue_99325[8f58]::function_with_bytes::BYTES)) }, substs: [], promoted: () }) }], user_self_ty: None }) }, span: $DIR/issue-99325.rs:11:16: 11:68, inferred_ty: fn() -> &'static [u8] {function_with_bytes::<&*b"AAAA">}
+| 1: user_ty: Canonical { max_universe: U0, variables: [], value: TypeOf(DefId(0:3 ~ issue_99325[8f58]::function_with_bytes), UserSubsts { substs: [Const { ty: &'static [u8; 4], kind: Unevaluated(UnevaluatedConst { def: WithOptConstParam { did: DefId(0:8 ~ issue_99325[8f58]::main::{constant#1}), const_param_did: Some(DefId(0:4 ~ issue_99325[8f58]::function_with_bytes::BYTES)) }, substs: [] }) }], user_self_ty: None }) }, span: $DIR/issue-99325.rs:11:16: 11:68, inferred_ty: fn() -> &'static [u8] {function_with_bytes::<&*b"AAAA">}
 |
 fn main() -> () {
     let mut _0: ();                      // return place in scope 0 at $DIR/issue-99325.rs:+0:15: +0:15
diff --git a/src/tools/clippy/clippy_lints/src/non_copy_const.rs b/src/tools/clippy/clippy_lints/src/non_copy_const.rs
index 72c86f28bbc..b1588452732 100644
--- a/src/tools/clippy/clippy_lints/src/non_copy_const.rs
+++ b/src/tools/clippy/clippy_lints/src/non_copy_const.rs
@@ -195,7 +195,7 @@ fn is_value_unfrozen_expr<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId, def_id: D
 
     let result = cx.tcx.const_eval_resolve(
         cx.param_env,
-        ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs),
+        mir::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs),
         None,
     );
     is_value_unfrozen_raw(cx, result, ty)
diff --git a/src/tools/clippy/clippy_utils/src/consts.rs b/src/tools/clippy/clippy_utils/src/consts.rs
index 1b8a9c05559..fa6766f7cfe 100644
--- a/src/tools/clippy/clippy_utils/src/consts.rs
+++ b/src/tools/clippy/clippy_utils/src/consts.rs
@@ -424,7 +424,7 @@ impl<'a, 'tcx> ConstEvalLateContext<'a, 'tcx> {
                     .tcx
                     .const_eval_resolve(
                         self.param_env,
-                        ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs),
+                        mir::UnevaluatedConst::new(ty::WithOptConstParam::unknown(def_id), substs),
                         None,
                     )
                     .ok()