Rollup merge of #83040 - lcnr:unused-ct-substs, r=oli-obk

extract `ConstKind::Unevaluated` into a struct

r? `@oli-obk`

Author: Dylan-DPC

compiler/rustc_codegen_cranelift/src/constant.rs

@@ -45,9 +45,9 @@ pub(crate) fn check_constants(fx: &mut FunctionCx<'_, '_, '_>) -> bool {
         };
         match const_.val {
             ConstKind::Value(_) => {}
-            ConstKind::Unevaluated(def, ref substs, promoted) => {
+            ConstKind::Unevaluated(unevaluated) => {
                 if let Err(err) =
-                    fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), def, substs, promoted, None)
+                    fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), unevaluated, None)
                 {
                     all_constants_ok = false;
                     match err {
@@ -122,14 +122,14 @@ pub(crate) fn codegen_constant<'tcx>(
     };
     let const_val = match const_.val {
         ConstKind::Value(const_val) => const_val,
-        ConstKind::Unevaluated(def, ref substs, promoted) if fx.tcx.is_static(def.did) => {
+        ConstKind::Unevaluated(ty::Unevaluated { def, substs, promoted }) if fx.tcx.is_static(def.did) => {
             assert!(substs.is_empty());
             assert!(promoted.is_none());
 
             return codegen_static_ref(fx, def.did, fx.layout_of(const_.ty)).to_cvalue(fx);
         }
-        ConstKind::Unevaluated(def, ref substs, promoted) => {
-            match fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), def, substs, promoted, None) {
+        ConstKind::Unevaluated(unevaluated) => {
+            match fx.tcx.const_eval_resolve(ParamEnv::reveal_all(), unevaluated, None) {
                 Ok(const_val) => const_val,
                 Err(_) => {
                     span_bug!(constant.span, "erroneous constant not captured by required_consts");

compiler/rustc_codegen_ssa/src/mir/constant.rs

@@ -30,10 +30,10 @@ 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(ct) => self
                 .cx
                 .tcx()
-                .const_eval_resolve(ty::ParamEnv::reveal_all(), def, substs, promoted, None)
+                .const_eval_resolve(ty::ParamEnv::reveal_all(), ct, None)
                 .map_err(|err| {
                     self.cx.tcx().sess.span_err(constant.span, "erroneous constant encountered");
                     err

compiler/rustc_infer/src/infer/mod.rs

@@ -18,7 +18,6 @@ use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_middle::infer::canonical::{Canonical, CanonicalVarValues};
 use rustc_middle::infer::unify_key::{ConstVarValue, ConstVariableValue};
 use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind, ToType};
-use rustc_middle::mir;
 use rustc_middle::mir::interpret::EvalToConstValueResult;
 use rustc_middle::traits::select;
 use rustc_middle::ty::error::{ExpectedFound, TypeError, UnconstrainedNumeric};
@@ -1499,9 +1498,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
     pub fn const_eval_resolve(
         &self,
         param_env: ty::ParamEnv<'tcx>,
-        def: ty::WithOptConstParam<DefId>,
-        substs: SubstsRef<'tcx>,
-        promoted: Option<mir::Promoted>,
+        ty::Unevaluated { def, substs, promoted }: ty::Unevaluated<'tcx>,
         span: Option<Span>,
     ) -> EvalToConstValueResult<'tcx> {
         let mut original_values = OriginalQueryValues::default();
@@ -1510,7 +1507,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         let (param_env, substs) = canonical.value;
         // 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.
-        self.tcx.const_eval_resolve(param_env, def, substs, promoted, span)
+        self.tcx.const_eval_resolve(param_env, ty::Unevaluated { def, substs, promoted }, span)
     }
 
     /// If `typ` is a type variable of some kind, resolve it one level

compiler/rustc_middle/src/mir/interpret/queries.rs

@@ -1,7 +1,7 @@
 use super::{ErrorHandled, EvalToConstValueResult, GlobalId};
 
 use crate::mir;
-use crate::ty::subst::{InternalSubsts, SubstsRef};
+use crate::ty::subst::InternalSubsts;
 use crate::ty::{self, TyCtxt};
 use rustc_hir::def_id::DefId;
 use rustc_span::Span;
@@ -35,14 +35,12 @@ impl<'tcx> TyCtxt<'tcx> {
     pub fn const_eval_resolve(
         self,
         param_env: ty::ParamEnv<'tcx>,
-        def: ty::WithOptConstParam<DefId>,
-        substs: SubstsRef<'tcx>,
-        promoted: Option<mir::Promoted>,
+        ct: ty::Unevaluated<'tcx>,
         span: Option<Span>,
     ) -> EvalToConstValueResult<'tcx> {
-        match ty::Instance::resolve_opt_const_arg(self, param_env, def, substs) {
+        match ty::Instance::resolve_opt_const_arg(self, param_env, ct.def, ct.substs) {
             Ok(Some(instance)) => {
-                let cid = GlobalId { instance, promoted };
+                let cid = GlobalId { instance, promoted: ct.promoted };
                 self.const_eval_global_id(param_env, cid, span)
             }
             Ok(None) => Err(ErrorHandled::TooGeneric),

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(
-                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

@@ -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(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),
@@ -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`
@@ -132,7 +140,8 @@ impl<'tcx> ConstKind<'tcx> {
             let (param_env, substs) = param_env_and_substs.into_parts();
             // try to resolve e.g. associated constants to their definition on an impl, and then
             // evaluate the const.
-            match tcx.const_eval_resolve(param_env, def, substs, promoted, None) {
+            match tcx.const_eval_resolve(param_env, ty::Unevaluated { def, substs, promoted }, None)
+            {
                 // NOTE(eddyb) `val` contains no lifetimes/types/consts,
                 // and we use the original type, so nothing from `substs`
                 // (which may be identity substs, see above),

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, 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(a_def, a_substs, None),
-            ty::ConstKind::Unevaluated(b_def, b_substs, None),
-        ) if tcx.features().const_evaluatable_checked && !relation.visit_ct_substs() => {
-            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() =>
+        {
+            tcx.try_unify_abstract_consts(((au.def, au.substs), (bu.def, bu.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(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)?;
+                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,
             }));
         }