extract ConstKind::Unevaluated into a struct

compiler/rustc_codegen_ssa/src/mir/constant.rs

@@ -30,7 +30,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
             mir::ConstantKind::Val(val, _) => return Ok(val),
         };
         match ct.val {
-            ty::ConstKind::Unevaluated(def, substs, promoted) => self
+            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => self
                 .cx
                 .tcx()
                 .const_eval_resolve(ty::ParamEnv::reveal_all(), def, substs, promoted, None)

compiler/rustc_middle/src/ty/consts.rs

@@ -98,18 +98,18 @@ impl<'tcx> Const<'tcx> {
                 let name = tcx.hir().name(hir_id);
                 ty::ConstKind::Param(ty::ParamConst::new(index, name))
             }
-            _ => ty::ConstKind::Unevaluated(
+            _ => ty::ConstKind::Unevaluated(ty::Unevaluated {
-                def.to_global(),
+                def: def.to_global(),
-                InternalSubsts::identity_for_item(tcx, def.did.to_def_id()),
+                substs: InternalSubsts::identity_for_item(tcx, def.did.to_def_id()),
-                None,
+                promoted: None,
-            ),
+            }),
         };
 
         tcx.mk_const(ty::Const { val, ty })
     }
 
-    #[inline]
     /// Interns the given value as a constant.
+    #[inline]
     pub fn from_value(tcx: TyCtxt<'tcx>, val: ConstValue<'tcx>, ty: Ty<'tcx>) -> &'tcx Self {
         tcx.mk_const(Self { val: ConstKind::Value(val), ty })
     }

compiler/rustc_middle/src/ty/consts/kind.rs

@@ -12,10 +12,18 @@ use rustc_macros::HashStable;
 use rustc_target::abi::Size;
 
 use super::ScalarInt;
+/// An unevaluated, potentially generic, constant.
+#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable)]
+#[derive(Hash, HashStable)]
+pub struct Unevaluated<'tcx> {
+    pub def: ty::WithOptConstParam<DefId>,
+    pub substs: SubstsRef<'tcx>,
+    pub promoted: Option<Promoted>,
+}
 
 /// Represents a constant in Rust.
-#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable, Hash)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable)]
-#[derive(HashStable)]
+#[derive(Hash, HashStable)]
 pub enum ConstKind<'tcx> {
     /// A const generic parameter.
     Param(ty::ParamConst),
@@ -31,7 +39,7 @@ 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(ty::WithOptConstParam<DefId>, SubstsRef<'tcx>, Option<Promoted>),
+    Unevaluated(Unevaluated<'tcx>),
 
     /// Used to hold computed value.
     Value(ConstValue<'tcx>),
@@ -102,7 +110,7 @@ impl<'tcx> ConstKind<'tcx> {
         tcx: TyCtxt<'tcx>,
         param_env: ParamEnv<'tcx>,
     ) -> Option<Result<ConstValue<'tcx>, ErrorReported>> {
-        if let ConstKind::Unevaluated(def, substs, promoted) = self {
+        if let ConstKind::Unevaluated(Unevaluated { def, substs, promoted }) = self {
             use crate::mir::interpret::ErrorHandled;
 
             // HACK(eddyb) this erases lifetimes even though `const_eval_resolve`

compiler/rustc_middle/src/ty/flags.rs

@@ -270,10 +270,7 @@ impl FlagComputation {
     fn add_const(&mut self, c: &ty::Const<'_>) {
         self.add_ty(c.ty);
         match c.val {
-            ty::ConstKind::Unevaluated(_, substs, _) => {
+            ty::ConstKind::Unevaluated(unevaluated) => self.add_unevaluated_const(unevaluated),
-                self.add_substs(substs);
-                self.add_flags(TypeFlags::HAS_CT_PROJECTION);
-            }
             ty::ConstKind::Infer(infer) => {
                 self.add_flags(TypeFlags::STILL_FURTHER_SPECIALIZABLE);
                 match infer {
@@ -297,6 +294,11 @@ impl FlagComputation {
         }
     }
 
+    fn add_unevaluated_const(&mut self, ct: ty::Unevaluated<'tcx>) {
+        self.add_substs(ct.substs);
+        self.add_flags(TypeFlags::HAS_CT_PROJECTION);
+    }
+
     fn add_existential_projection(&mut self, projection: &ty::ExistentialProjection<'_>) {
         self.add_substs(projection.substs);
         self.add_ty(projection.ty);

compiler/rustc_middle/src/ty/mod.rs

@@ -55,7 +55,7 @@ pub use rustc_type_ir::*;
 
 pub use self::binding::BindingMode;
 pub use self::binding::BindingMode::*;
-pub use self::consts::{Const, ConstInt, ConstKind, InferConst, ScalarInt, ValTree};
+pub use self::consts::{Const, ConstInt, ConstKind, InferConst, ScalarInt, Unevaluated, ValTree};
 pub use self::context::{
     tls, CanonicalUserType, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations,
     CtxtInterners, DelaySpanBugEmitted, FreeRegionInfo, GeneratorInteriorTypeCause, GlobalCtxt,

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -915,7 +915,7 @@ pub trait PrettyPrinter<'tcx>:
         }
 
         match ct.val {
-            ty::ConstKind::Unevaluated(def, substs, promoted) => {
+            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => {
                 if let Some(promoted) = promoted {
                     p!(print_value_path(def.did, substs));
                     p!(write("::{:?}", promoted));

compiler/rustc_middle/src/ty/relate.rs

@@ -531,24 +531,26 @@ pub fn super_relate_consts<R: TypeRelation<'tcx>>(
             check_const_value_eq(relation, a_val, b_val, a, b)?
         }
 
-        (
+        (ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu))
-            ty::ConstKind::Unevaluated(a_def, a_substs, None),
+            if tcx.features().const_evaluatable_checked && !relation.visit_ct_substs() =>
-            ty::ConstKind::Unevaluated(b_def, b_substs, None),
+        {
-        ) if tcx.features().const_evaluatable_checked && !relation.visit_ct_substs() => {
+            tcx.try_unify_abstract_consts(((au.def, au.substs), (bu.def, bu.substs)))
-            tcx.try_unify_abstract_consts(((a_def, a_substs), (b_def, b_substs)))
         }
 
         // While this is slightly incorrect, it shouldn't matter for `min_const_generics`
         // and is the better alternative to waiting until `const_evaluatable_checked` can
         // be stabilized.
-        (
+        (ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu))
-            ty::ConstKind::Unevaluated(a_def, a_substs, a_promoted),
+            if au.def == bu.def && au.promoted == bu.promoted =>
-            ty::ConstKind::Unevaluated(b_def, b_substs, b_promoted),
+        {
-        ) if a_def == b_def && a_promoted == b_promoted => {
             let substs =
-                relation.relate_with_variance(ty::Variance::Invariant, a_substs, b_substs)?;
+                relation.relate_with_variance(ty::Variance::Invariant, au.substs, bu.substs)?;
             return Ok(tcx.mk_const(ty::Const {
-                val: ty::ConstKind::Unevaluated(a_def, substs, a_promoted),
+                val: ty::ConstKind::Unevaluated(ty::Unevaluated {
+                    def: au.def,
+                    substs,
+                    promoted: au.promoted,
+                }),
                 ty: a.ty,
             }));
         }

compiler/rustc_middle/src/ty/structural_impls.rs

@@ -1031,8 +1031,12 @@ impl<'tcx> TypeFoldable<'tcx> for ty::ConstKind<'tcx> {
         match self {
             ty::ConstKind::Infer(ic) => ty::ConstKind::Infer(ic.fold_with(folder)),
             ty::ConstKind::Param(p) => ty::ConstKind::Param(p.fold_with(folder)),
-            ty::ConstKind::Unevaluated(did, substs, promoted) => {
+            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => {
-                ty::ConstKind::Unevaluated(did, substs.fold_with(folder), promoted)
+                ty::ConstKind::Unevaluated(ty::Unevaluated {
+                    def,
+                    substs: substs.fold_with(folder),
+                    promoted,
+                })
             }
             ty::ConstKind::Value(_)
             | ty::ConstKind::Bound(..)
@@ -1045,7 +1049,7 @@ impl<'tcx> TypeFoldable<'tcx> for ty::ConstKind<'tcx> {
         match *self {
             ty::ConstKind::Infer(ic) => ic.visit_with(visitor),
             ty::ConstKind::Param(p) => p.visit_with(visitor),
-            ty::ConstKind::Unevaluated(_, substs, _) => substs.visit_with(visitor),
+            ty::ConstKind::Unevaluated(ct) => ct.substs.visit_with(visitor),
             ty::ConstKind::Value(_)
             | ty::ConstKind::Bound(..)
             | ty::ConstKind::Placeholder(_)

compiler/rustc_middle/src/ty/walk.rs

@@ -195,8 +195,8 @@ fn push_inner<'tcx>(stack: &mut TypeWalkerStack<'tcx>, parent: GenericArg<'tcx>)
                 | ty::ConstKind::Value(_)
                 | ty::ConstKind::Error(_) => {}
 
-                ty::ConstKind::Unevaluated(_, substs, _) => {
+                ty::ConstKind::Unevaluated(ct) => {
-                    stack.extend(substs.iter().rev());
+                    stack.extend(ct.substs.iter().rev());
                 }
             }
         }

compiler/rustc_mir/src/borrow_check/type_check/mod.rs

@@ -316,14 +316,12 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
             let tcx = self.tcx();
             let maybe_uneval = match constant.literal {
                 ConstantKind::Ty(ct) => match ct.val {
-                    ty::ConstKind::Unevaluated(def, substs, promoted) => {
+                    ty::ConstKind::Unevaluated(uv) => Some(uv),
-                        Some((def, substs, promoted))
-                    }
                     _ => None,
                 },
                 _ => None,
             };
-            if let Some((def, substs, promoted)) = maybe_uneval {
+            if let Some(ty::Unevaluated { def, substs, promoted }) = maybe_uneval {
                 if let Some(promoted) = promoted {
                     let check_err = |verifier: &mut TypeVerifier<'a, 'b, 'tcx>,
                                      promoted: &Body<'tcx>,

compiler/rustc_mir/src/interpret/operand.rs

@@ -560,7 +560,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         match val.val {
             ty::ConstKind::Param(_) | ty::ConstKind::Bound(..) => throw_inval!(TooGeneric),
             ty::ConstKind::Error(_) => throw_inval!(AlreadyReported(ErrorReported)),
-            ty::ConstKind::Unevaluated(def, substs, promoted) => {
+            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => {
                 let instance = self.resolve(def, substs)?;
                 Ok(self.eval_to_allocation(GlobalId { instance, promoted })?.into())
             }

compiler/rustc_mir/src/monomorphize/collector.rs

@@ -646,7 +646,7 @@ impl<'a, 'tcx> MirVisitor<'tcx> for MirNeighborCollector<'a, 'tcx> {
 
         match substituted_constant.val {
             ty::ConstKind::Value(val) => collect_const_value(self.tcx, val, self.output),
-            ty::ConstKind::Unevaluated(def, substs, promoted) => {
+            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => {
                 match self.tcx.const_eval_resolve(param_env, def, substs, promoted, None) {
                     Ok(val) => collect_const_value(self.tcx, val, self.output),
                     Err(ErrorHandled::Reported(ErrorReported) | ErrorHandled::Linted) => {}

compiler/rustc_mir/src/monomorphize/polymorphize.rs

@@ -299,7 +299,7 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
                 self.unused_parameters.clear(param.index);
                 ControlFlow::CONTINUE
             }
-            ty::ConstKind::Unevaluated(def, _, Some(p))
+            ty::ConstKind::Unevaluated(ty::Unevaluated { 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 =>
@@ -310,10 +310,10 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
                 self.visit_body(&promoted[p]);
                 ControlFlow::CONTINUE
             }
-            ty::ConstKind::Unevaluated(def, unevaluated_substs, None)
+            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted: None })
                 if self.tcx.def_kind(def.did) == DefKind::AnonConst =>
             {
-                self.visit_child_body(def.did, unevaluated_substs);
+                self.visit_child_body(def.did, substs);
                 ControlFlow::CONTINUE
             }
             _ => c.super_visit_with(self),

compiler/rustc_mir/src/transform/check_consts/qualifs.rs

@@ -247,7 +247,7 @@ where
 
     // Check the qualifs of the value of `const` items.
     if let Some(ct) = constant.literal.const_for_ty() {
-        if let ty::ConstKind::Unevaluated(def, _, promoted) = ct.val {
+        if let ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted }) = ct.val {
             assert!(promoted.is_none());
             // Don't peek inside trait associated constants.
             if cx.tcx.trait_of_item(def.did).is_none() {

compiler/rustc_mir/src/transform/const_prop.rs

@@ -491,7 +491,11 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                     let lint_only = match c.literal {
                         ConstantKind::Ty(ct) => match ct.val {
                             // Promoteds must lint and not error as the user didn't ask for them
-                            ConstKind::Unevaluated(_, _, Some(_)) => true,
+                            ConstKind::Unevaluated(ty::Unevaluated {
+                                def: _,
+                                substs: _,
+                                promoted: Some(_),
+                            }) => true,
                             // Out of backwards compatibility we cannot report hard errors in unused
                             // generic functions using associated constants of the generic parameters.
                             _ => c.literal.needs_subst(),

compiler/rustc_mir/src/transform/inline.rs

@@ -630,7 +630,7 @@ impl Inliner<'tcx> {
                 caller_body.required_consts.extend(
                     callee_body.required_consts.iter().copied().filter(|&ct| {
                         match ct.literal.const_for_ty() {
-                            Some(ct) => matches!(ct.val, ConstKind::Unevaluated(_, _, _)),
+                            Some(ct) => matches!(ct.val, ConstKind::Unevaluated(_)),
                             None => true,
                         }
                     }),

compiler/rustc_mir/src/transform/promote_consts.rs

@@ -1001,17 +1001,17 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                     literal: tcx
                         .mk_const(ty::Const {
                             ty,
-                            val: ty::ConstKind::Unevaluated(
+                            val: ty::ConstKind::Unevaluated(ty::Unevaluated {
                                 def,
-                                InternalSubsts::for_item(tcx, def.did, |param, _| {
+                                substs: InternalSubsts::for_item(tcx, def.did, |param, _| {
                                     if let ty::GenericParamDefKind::Lifetime = param.kind {
                                         tcx.lifetimes.re_erased.into()
                                     } else {
                                         tcx.mk_param_from_def(param)
                                     }
                                 }),
-                                Some(promoted_id),
+                                promoted: Some(promoted_id),
-                            ),
+                            }),
                         })
                         .into(),
                 }))

compiler/rustc_mir/src/transform/required_consts.rs

@@ -15,7 +15,7 @@ impl<'a, 'tcx> RequiredConstsVisitor<'a, 'tcx> {
 impl<'a, 'tcx> Visitor<'tcx> for RequiredConstsVisitor<'a, 'tcx> {
     fn visit_constant(&mut self, constant: &Constant<'tcx>, _: Location) {
         if let Some(ct) = constant.literal.const_for_ty() {
-            if let ConstKind::Unevaluated(_, _, _) = ct.val {
+            if let ConstKind::Unevaluated(_) = ct.val {
                 self.required_consts.push(*constant);
             }
         }

compiler/rustc_mir_build/src/thir/cx/expr.rs

@@ -707,11 +707,11 @@ impl<'thir, 'tcx> Cx<'thir, 'tcx> {
                                 // and not the beginning of discriminants (which is always `0`)
                                 let substs = InternalSubsts::identity_for_item(self.tcx(), did);
                                 let lhs = mk_const(self.tcx().mk_const(ty::Const {
-                                    val: ty::ConstKind::Unevaluated(
+                                    val: ty::ConstKind::Unevaluated(ty::Unevaluated {
-                                        ty::WithOptConstParam::unknown(did),
+                                        def: ty::WithOptConstParam::unknown(did),
                                         substs,
-                                        None,
+                                        promoted: None,
-                                    ),
+                                    }),
                                     ty: var_ty,
                                 }));
                                 let bin =
@@ -905,11 +905,11 @@ impl<'thir, 'tcx> Cx<'thir, 'tcx> {
                 debug!("convert_path_expr: (const) user_ty={:?}", user_ty);
                 ExprKind::Literal {
                     literal: self.tcx.mk_const(ty::Const {
-                        val: ty::ConstKind::Unevaluated(
+                        val: ty::ConstKind::Unevaluated(ty::Unevaluated {
-                            ty::WithOptConstParam::unknown(def_id),
+                            def: ty::WithOptConstParam::unknown(def_id),
                             substs,
-                            None,
+                            promoted: None,
-                        ),
+                        }),
                         ty: self.typeck_results().node_type(expr.hir_id),
                     }),
                     user_ty,

compiler/rustc_trait_selection/src/traits/auto_trait.rs

@@ -803,7 +803,12 @@ impl AutoTraitFinder<'tcx> {
                 }
                 ty::PredicateKind::ConstEquate(c1, c2) => {
                     let evaluate = |c: &'tcx ty::Const<'tcx>| {
-                        if let ty::ConstKind::Unevaluated(def, substs, promoted) = c.val {
+                        if let ty::ConstKind::Unevaluated(ty::Unevaluated {
+                            def,
+                            substs,
+                            promoted,
+                        }) = c.val
+                        {
                             match select.infcx().const_eval_resolve(
                                 obligation.param_env,
                                 def,

compiler/rustc_trait_selection/src/traits/const_evaluatable.rs

@@ -239,7 +239,9 @@ impl AbstractConst<'tcx> {
         ct: &ty::Const<'tcx>,
     ) -> Result<Option<AbstractConst<'tcx>>, ErrorReported> {
         match ct.val {
-            ty::ConstKind::Unevaluated(def, substs, None) => AbstractConst::new(tcx, def, substs),
+            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted: _ }) => {
+                AbstractConst::new(tcx, def, substs)
+            }
             ty::ConstKind::Error(_) => Err(ErrorReported),
             _ => Ok(None),
         }
@@ -532,22 +534,25 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
             if let Some(next) = self.build_terminator(block.terminator())? {
                 block = &self.body.basic_blocks()[next];
             } else {
-                assert_eq!(self.locals[mir::RETURN_PLACE], self.nodes.last().unwrap());
+                break;
-                // `AbstractConst`s should not contain any promoteds as they require references which
-                // are not allowed.
-                assert!(!self.nodes.iter().any(|n| matches!(
-                    n.node,
-                    Node::Leaf(ty::Const { val: ty::ConstKind::Unevaluated(_, _, Some(_)), ty: _ })
-                )));
-
-                self.nodes[self.locals[mir::RETURN_PLACE]].used = true;
-                if let Some(&unused) = self.nodes.iter().find(|n| !n.used) {
-                    self.error(Some(unused.span), "dead code")?;
-                }
-
-                return Ok(self.tcx.arena.alloc_from_iter(self.nodes.into_iter().map(|n| n.node)));
             }
         }
+
+        assert_eq!(self.locals[mir::RETURN_PLACE], self.nodes.last().unwrap());
+        for n in self.nodes.iter() {
+            if let Node::Leaf(ty::Const { val: ty::ConstKind::Unevaluated(ct), ty: _ }) = n.node {
+                // `AbstractConst`s should not contain any promoteds as they require references which
+                // are not allowed.
+                assert_eq!(ct.promoted, None);
+            }
+        }
+
+        self.nodes[self.locals[mir::RETURN_PLACE]].used = true;
+        if let Some(&unused) = self.nodes.iter().find(|n| !n.used) {
+            self.error(Some(unused.span), "dead code")?;
+        }
+
+        Ok(self.tcx.arena.alloc_from_iter(self.nodes.into_iter().map(|n| n.node)))
     }
 }
 
@@ -673,10 +678,16 @@ pub(super) fn try_unify<'tcx>(
                 // we do not want to use `assert_eq!(a(), b())` to infer that `N` and `M` have to be `1`. This
                 // means that we only allow inference variables if they are equal.
                 (ty::ConstKind::Infer(a_val), ty::ConstKind::Infer(b_val)) => a_val == b_val,
-                (
+                // We expand generic anonymous constants at the start of this function, so this
-                    ty::ConstKind::Unevaluated(a_def, a_substs, None),
+                // branch should only be taking when dealing with associated constants, at
-                    ty::ConstKind::Unevaluated(b_def, b_substs, None),
+                // which point directly comparing them seems like the desired behavior.
-                ) => a_def == b_def && a_substs == b_substs,
+                //
+                // FIXME(const_evaluatable_checked): This isn't actually the case.
+                // We also take this branch for concrete anonymous constants and
+                // expand generic anonymous constants with concrete substs.
+                (ty::ConstKind::Unevaluated(a_uv), ty::ConstKind::Unevaluated(b_uv)) => {
+                    a_uv == b_uv
+                }
                 // FIXME(const_evaluatable_checked): We may want to either actually try
                 // to evaluate `a_ct` and `b_ct` if they are are fully concrete or something like
                 // this, for now we just return false here.

compiler/rustc_trait_selection/src/traits/fulfill.rs

@@ -516,15 +516,13 @@ impl<'a, 'b, 'tcx> FulfillProcessor<'a, 'b, 'tcx> {
                         // if the constants depend on generic parameters.
                         //
                         // Let's just see where this breaks :shrug:
-                        if let (
+                        if let (ty::ConstKind::Unevaluated(a), ty::ConstKind::Unevaluated(b)) =
-                            ty::ConstKind::Unevaluated(a_def, a_substs, None),
+                            (c1.val, c2.val)
-                            ty::ConstKind::Unevaluated(b_def, b_substs, None),
-                        ) = (c1.val, c2.val)
                         {
                             if self
                                 .selcx
                                 .tcx()
-                                .try_unify_abstract_consts(((a_def, a_substs), (b_def, b_substs)))
+                                .try_unify_abstract_consts(((a.def, a.substs), (b.def, b.substs)))
                             {
                                 return ProcessResult::Changed(vec![]);
                             }
@@ -534,7 +532,12 @@ impl<'a, 'b, 'tcx> FulfillProcessor<'a, 'b, 'tcx> {
                     let stalled_on = &mut pending_obligation.stalled_on;
 
                     let mut evaluate = |c: &'tcx Const<'tcx>| {
-                        if let ty::ConstKind::Unevaluated(def, substs, promoted) = c.val {
+                        if let ty::ConstKind::Unevaluated(ty::Unevaluated {
+                            def,
+                            substs,
+                            promoted,
+                        }) = c.val
+                        {
                             match self.selcx.infcx().const_eval_resolve(
                                 obligation.param_env,
                                 def,

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -556,7 +556,12 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     debug!(?c1, ?c2, "evaluate_predicate_recursively: equating consts");
 
                     let evaluate = |c: &'tcx ty::Const<'tcx>| {
-                        if let ty::ConstKind::Unevaluated(def, substs, promoted) = c.val {
+                        if let ty::ConstKind::Unevaluated(ty::Unevaluated {
+                            def,
+                            substs,
+                            promoted,
+                        }) = c.val
+                        {
                             self.infcx
                                 .const_eval_resolve(
                                     obligation.param_env,

compiler/rustc_trait_selection/src/traits/wf.rs

@@ -430,7 +430,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
 
                 GenericArgKind::Const(constant) => {
                     match constant.val {
-                        ty::ConstKind::Unevaluated(def, substs, promoted) => {
+                        ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) => {
                             assert!(promoted.is_none());
 
                             let obligations = self.nominal_obligations(def.did, substs);

compiler/rustc_typeck/src/collect.rs

@@ -2212,10 +2212,11 @@ fn const_evaluatable_predicates_of<'tcx>(
         fn visit_anon_const(&mut self, c: &'tcx hir::AnonConst) {
             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(def, substs, None) = ct.val {
+            if let ty::ConstKind::Unevaluated(uv) = ct.val {
+                assert_eq!(uv.promoted, None);
                 let span = self.tcx.hir().span(c.hir_id);
                 self.preds.insert((
-                    ty::PredicateKind::ConstEvaluatable(def, substs).to_predicate(self.tcx),
+                    ty::PredicateKind::ConstEvaluatable(uv.def, uv.substs).to_predicate(self.tcx),
                     span,
                 ));
             }