extract ConstKind::Unevaluated into a struct

compiler/rustc_codegen_ssa/src/mir/constant.rs

@@ -25,7 +25,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         constant: &mir::Constant<'tcx>,
     ) -> Result<ConstValue<'tcx>, ErrorHandled> {
         match self.monomorphize(constant.literal).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

@@ -96,18 +96,18 @@ impl<'tcx> Const<'tcx> {
                 let name = tcx.hir().name(hir_id);
                 ty::ConstKind::Param(ty::ParamConst::new(index, name))
             }
-            _ => ty::ConstKind::Unevaluated(
-                def.to_global(),
-                InternalSubsts::identity_for_item(tcx, def.did.to_def_id()),
-                None,
-            ),
+            _ => ty::ConstKind::Unevaluated(ty::Unevaluated {
+                def: def.to_global(),
+                substs: InternalSubsts::identity_for_item(tcx, def.did.to_def_id()),
+                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

@@ -9,9 +9,18 @@ use rustc_hir::def_id::DefId;
 use rustc_macros::HashStable;
 use rustc_target::abi::Size;
 
+/// 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(HashStable)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord, TyEncodable, TyDecodable)]
+#[derive(Hash, HashStable)]
 pub enum ConstKind<'tcx> {
     /// A const generic parameter.
     Param(ty::ParamConst),
@@ -27,7 +36,7 @@ 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>),
@@ -93,7 +102,7 @@ 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, _) => {
-                self.add_substs(substs);
-                self.add_flags(TypeFlags::HAS_CT_PROJECTION);
-            }
+            ty::ConstKind::Unevaluated(unevaluated) => self.add_unevaluated_const(unevaluated),
             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};
+pub use self::consts::{Const, ConstInt, ConstKind, InferConst, ScalarInt, Unevaluated};
 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

@@ -587,11 +587,10 @@ pub fn super_relate_consts<R: TypeRelation<'tcx>>(
             new_val.map(ty::ConstKind::Value)
         }
 
-        (
-            ty::ConstKind::Unevaluated(a_def, a_substs, None),
-            ty::ConstKind::Unevaluated(b_def, b_substs, None),
-        ) if tcx.features().const_evaluatable_checked && !relation.visit_ct_substs() => {
-            if tcx.try_unify_abstract_consts(((a_def, a_substs), (b_def, b_substs))) {
+        (ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu))
+            if tcx.features().const_evaluatable_checked && !relation.visit_ct_substs() =>
+        {
+            if tcx.try_unify_abstract_consts(((au.def, au.substs), (bu.def, bu.substs))) {
                 Ok(a.val)
             } else {
                 Err(TypeError::ConstMismatch(expected_found(relation, a, b)))
@@ -601,13 +600,16 @@ pub fn super_relate_consts<R: TypeRelation<'tcx>>(
         // 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(a_def, a_substs, a_promoted),
-            ty::ConstKind::Unevaluated(b_def, b_substs, b_promoted),
-        ) if a_def == b_def && a_promoted == b_promoted => {
+        (ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu))
+            if au.def == bu.def && au.promoted == bu.promoted =>
+        {
             let substs =
-                relation.relate_with_variance(ty::Variance::Invariant, a_substs, b_substs)?;
-            Ok(ty::ConstKind::Unevaluated(a_def, substs, a_promoted))
+                relation.relate_with_variance(ty::Variance::Invariant, au.substs, bu.substs)?;
+            Ok(ty::ConstKind::Unevaluated(ty::Unevaluated {
+                def: au.def,
+                substs,
+                promoted: au.promoted,
+            }))
         }
         _ => Err(TypeError::ConstMismatch(expected_found(relation, a, b))),
     };

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(did, substs.fold_with(folder), promoted)
+            ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, 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, _) => {
-                    stack.extend(substs.iter().rev());
+                ty::ConstKind::Unevaluated(ct) => {
+                    stack.extend(ct.substs.iter().rev());
                 }
             }
         }

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

@@ -314,7 +314,9 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
             }
         } else {
             let tcx = self.tcx();
-            if let ty::ConstKind::Unevaluated(def, substs, promoted) = constant.literal.val {
+            if let ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) =
+                constant.literal.val
+            {
                 if let Some(promoted) = promoted {
                     let check_err = |verifier: &mut TypeVerifier<'a, 'b, 'tcx>,
                                      promoted: &Body<'tcx>,

compiler/rustc_mir/src/interpret/operand.rs

@@ -566,7 +566,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         let val_val = 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)?;
                 return 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

@@ -246,7 +246,9 @@ where
     };
 
     // Check the qualifs of the value of `const` items.
-    if let ty::ConstKind::Unevaluated(def, _, promoted) = constant.literal.val {
+    if let ty::ConstKind::Unevaluated(ty::Unevaluated { def, substs: _, promoted }) =
+        constant.literal.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

@@ -490,7 +490,7 @@ impl<'mir, 'tcx> ConstPropagator<'mir, 'tcx> {
                 if let Some(lint_root) = self.lint_root(source_info) {
                     let lint_only = match c.literal.val {
                         // Promoteds must lint and not error as the user didn't ask for them
-                        ConstKind::Unevaluated(_, _, Some(_)) => true,
+                        ConstKind::Unevaluated(uv) if uv.promoted.is_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

@@ -638,7 +638,7 @@ impl Inliner<'tcx> {
                 // because we are calling `subst_and_normalize_erasing_regions`.
                 caller_body.required_consts.extend(
                     callee_body.required_consts.iter().copied().filter(|&constant| {
-                        matches!(constant.literal.val, ConstKind::Unevaluated(_, _, _))
+                        matches!(constant.literal.val, ConstKind::Unevaluated(_))
                     }),
                 );
             }

compiler/rustc_mir/src/transform/promote_consts.rs

@@ -1000,17 +1000,17 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                     user_ty: None,
                     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),
+                        }),
                     }),
                 }))
             };

compiler/rustc_mir/src/transform/required_consts.rs

@@ -16,7 +16,7 @@ impl<'a, 'tcx> Visitor<'tcx> for RequiredConstsVisitor<'a, 'tcx> {
     fn visit_constant(&mut self, constant: &Constant<'tcx>, _: Location) {
         let const_kind = constant.literal.val;
 
-        if let ConstKind::Unevaluated(_, _, _) = const_kind {
+        if let ConstKind::Unevaluated(_) = const_kind {
             self.required_consts.push(*constant);
         }
     }

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

@@ -692,11 +692,11 @@ 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(
-                                        ty::WithOptConstParam::unknown(did),
+                                    val: ty::ConstKind::Unevaluated(ty::Unevaluated {
+                                        def: ty::WithOptConstParam::unknown(did),
                                         substs,
-                                        None,
-                                    ),
+                                        promoted: None,
+                                    }),
                                     ty: var_ty,
                                 }));
                                 let bin =
@@ -890,11 +890,11 @@ 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(
-                            ty::WithOptConstParam::unknown(def_id),
+                        val: ty::ConstKind::Unevaluated(ty::Unevaluated {
+                            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,