Completely remove ConstnessAnd

Author: oli-obk

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -31,7 +31,7 @@ use rustc_middle::ty::fold::TypeFoldable;
 use rustc_middle::ty::subst::{GenericArgKind, SubstsRef, UserSubsts};
 use rustc_middle::ty::{
     self, CanonicalUserTypeAnnotation, CanonicalUserTypeAnnotations, OpaqueTypeKey, RegionVid,
-    ToPredicate, Ty, TyCtxt, UserType, UserTypeAnnotationIndex, WithConstness,
+    ToPredicate, Ty, TyCtxt, UserType, UserTypeAnnotationIndex,
 };
 use rustc_span::def_id::CRATE_DEF_ID;
 use rustc_span::{Span, DUMMY_SP};

compiler/rustc_infer/src/traits/engine.rs

@@ -2,7 +2,7 @@ use crate::infer::InferCtxt;
 use crate::traits::Obligation;
 use rustc_data_structures::fx::FxHashMap;
 use rustc_hir::def_id::DefId;
-use rustc_middle::ty::{self, ToPredicate, Ty, WithConstness};
+use rustc_middle::ty::{self, ToPredicate, Ty};
 
 use super::FulfillmentError;
 use super::{ObligationCause, PredicateObligation};

compiler/rustc_infer/src/traits/util.rs

@@ -3,7 +3,7 @@ use smallvec::smallvec;
 use crate::infer::outlives::components::{push_outlives_components, Component};
 use crate::traits::{Obligation, ObligationCause, PredicateObligation};
 use rustc_data_structures::fx::{FxHashSet, FxIndexSet};
-use rustc_middle::ty::{self, ToPredicate, TyCtxt, WithConstness};
+use rustc_middle::ty::{self, ToPredicate, TyCtxt};
 use rustc_span::symbol::Ident;
 use rustc_span::Span;
 

compiler/rustc_middle/src/ty/mod.rs

@@ -846,20 +846,6 @@ impl ToPredicate<'tcx> for Binder<'tcx, PredicateKind<'tcx>> {
     }
 }
 
-impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<PolyTraitRef<'tcx>> {
-    fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
-        self.value
-            .map_bound(|trait_ref| {
-                PredicateKind::Trait(ty::TraitPredicate {
-                    trait_ref,
-                    constness: self.constness,
-                    polarity: ty::ImplPolarity::Positive,
-                })
-            })
-            .to_predicate(tcx)
-    }
-}
-
 impl<'tcx> ToPredicate<'tcx> for PolyTraitPredicate<'tcx> {
     fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
         self.map_bound(PredicateKind::Trait).to_predicate(tcx)
@@ -1391,33 +1377,23 @@ impl<'tcx> ParamEnv<'tcx> {
     }
 }
 
-#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
-pub struct ConstnessAnd<T> {
-    pub constness: BoundConstness,
-    pub value: T,
-}
-
 // FIXME(ecstaticmorse): Audit all occurrences of `without_const().to_predicate(tcx)` to ensure that
 // the constness of trait bounds is being propagated correctly.
-pub trait WithConstness: Sized {
-    #[inline]
-    fn with_constness(self, constness: BoundConstness) -> ConstnessAnd<Self> {
-        ConstnessAnd { constness, value: self }
-    }
-
+impl PolyTraitRef<'tcx> {
     #[inline]
-    fn with_const_if_const(self) -> ConstnessAnd<Self> {
-        self.with_constness(BoundConstness::ConstIfConst)
+    pub fn with_constness(self, constness: BoundConstness) -> PolyTraitPredicate<'tcx> {
+        self.map_bound(|trait_ref| ty::TraitPredicate {
+            trait_ref,
+            constness,
+            polarity: ty::ImplPolarity::Positive,
+        })
     }
-
     #[inline]
-    fn without_const(self) -> ConstnessAnd<Self> {
+    pub fn without_const(self) -> PolyTraitPredicate<'tcx> {
         self.with_constness(BoundConstness::NotConst)
     }
 }
 
-impl<T> WithConstness for T {}
-
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, TypeFoldable)]
 pub struct ParamEnvAnd<'tcx, T> {
     pub param_env: ParamEnv<'tcx>,

compiler/rustc_middle/src/ty/relate.rs

@@ -218,19 +218,6 @@ impl<'tcx> Relate<'tcx> for ty::BoundConstness {
     }
 }
 
-impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for ty::ConstnessAnd<T> {
-    fn relate<R: TypeRelation<'tcx>>(
-        relation: &mut R,
-        a: ty::ConstnessAnd<T>,
-        b: ty::ConstnessAnd<T>,
-    ) -> RelateResult<'tcx, ty::ConstnessAnd<T>> {
-        Ok(ty::ConstnessAnd {
-            constness: relation.relate(a.constness, b.constness)?,
-            value: relation.relate(a.value, b.value)?,
-        })
-    }
-}
-
 impl<'tcx> Relate<'tcx> for ast::Unsafety {
     fn relate<R: TypeRelation<'tcx>>(
         relation: &mut R,

compiler/rustc_middle/src/ty/sty.rs

@@ -8,9 +8,7 @@ use crate::infer::canonical::Canonical;
 use crate::ty::fold::ValidateBoundVars;
 use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef};
 use crate::ty::InferTy::{self, *};
-use crate::ty::{
-    self, AdtDef, DefIdTree, Discr, Ty, TyCtxt, TypeFlags, TypeFoldable, WithConstness,
-};
+use crate::ty::{self, AdtDef, DefIdTree, Discr, Ty, TyCtxt, TypeFlags, TypeFoldable};
 use crate::ty::{DelaySpanBugEmitted, List, ParamEnv, TyS};
 use polonius_engine::Atom;
 use rustc_data_structures::captures::Captures;

compiler/rustc_trait_selection/src/autoderef.rs

@@ -3,7 +3,7 @@ use crate::traits::{self, TraitEngine};
 use rustc_errors::struct_span_err;
 use rustc_hir as hir;
 use rustc_infer::infer::InferCtxt;
-use rustc_middle::ty::{self, TraitRef, Ty, TyCtxt, WithConstness};
+use rustc_middle::ty::{self, TraitRef, Ty, TyCtxt};
 use rustc_middle::ty::{ToPredicate, TypeFoldable};
 use rustc_session::{DiagnosticMessageId, Limit};
 use rustc_span::def_id::LOCAL_CRATE;

compiler/rustc_trait_selection/src/infer.rs

@@ -9,7 +9,6 @@ use rustc_middle::infer::canonical::{Canonical, CanonicalizedQueryResponse, Quer
 use rustc_middle::traits::query::Fallible;
 use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::ToPredicate;
-use rustc_middle::ty::WithConstness;
 use rustc_middle::ty::{self, Ty, TypeFoldable};
 use rustc_span::{Span, DUMMY_SP};
 

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

@@ -24,7 +24,7 @@ use rustc_middle::ty::error::ExpectedFound;
 use rustc_middle::ty::fold::TypeFolder;
 use rustc_middle::ty::{
     self, fast_reject, AdtKind, SubtypePredicate, ToPolyTraitRef, ToPredicate, Ty, TyCtxt,
-    TypeFoldable, WithConstness,
+    TypeFoldable,
 };
 use rustc_session::DiagnosticMessageId;
 use rustc_span::symbol::{kw, sym};

compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs

@@ -21,7 +21,7 @@ use rustc_hir::lang_items::LangItem;
 use rustc_hir::{AsyncGeneratorKind, GeneratorKind, Node};
 use rustc_middle::ty::{
     self, suggest_arbitrary_trait_bound, suggest_constraining_type_param, AdtKind, DefIdTree,
-    Infer, InferTy, ToPredicate, Ty, TyCtxt, TypeFoldable, WithConstness,
+    Infer, InferTy, ToPredicate, Ty, TyCtxt, TypeFoldable,
 };
 use rustc_middle::ty::{TypeAndMut, TypeckResults};
 use rustc_session::Limit;