| //! Various utilities for the next-trait-solver. |
| |
| use std::{ |
| iter, |
| ops::{self, ControlFlow}, |
| }; |
| |
| use base_db::Crate; |
| use hir_def::{BlockId, HasModule, lang_item::LangItem}; |
| use la_arena::Idx; |
| use rustc_abi::{Float, HasDataLayout, Integer, IntegerType, Primitive, ReprOptions}; |
| use rustc_type_ir::{ |
| ConstKind, CoroutineArgs, DebruijnIndex, FloatTy, INNERMOST, IntTy, Interner, |
| PredicatePolarity, RegionKind, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeSuperVisitable, |
| TypeVisitableExt, TypeVisitor, UintTy, UniverseIndex, |
| inherent::{ |
| AdtDef, GenericArg as _, GenericArgs as _, IntoKind, ParamEnv as _, SliceLike, Ty as _, |
| }, |
| lang_items::SolverTraitLangItem, |
| solve::SizedTraitKind, |
| }; |
| |
| use crate::{ |
| db::HirDatabase, |
| lower::{LifetimeElisionKind, TyLoweringContext}, |
| method_resolution::{TraitImpls, TyFingerprint}, |
| next_solver::{ |
| BoundConst, FxIndexMap, ParamEnv, Placeholder, PlaceholderConst, PlaceholderRegion, |
| infer::InferCtxt, |
| }, |
| }; |
| |
| use super::{ |
| Binder, BoundRegion, BoundTy, Clause, ClauseKind, Clauses, Const, DbInterner, EarlyBinder, |
| GenericArgs, Predicate, PredicateKind, Region, SolverDefId, TraitPredicate, TraitRef, Ty, |
| TyKind, |
| fold::{BoundVarReplacer, FnMutDelegate}, |
| }; |
| |
| #[derive(Clone, Debug)] |
| pub struct Discr<'db> { |
| /// Bit representation of the discriminant (e.g., `-128i8` is `0xFF_u128`). |
| pub val: u128, |
| pub ty: Ty<'db>, |
| } |
| |
| impl<'db> Discr<'db> { |
| /// Adds `1` to the value and wraps around if the maximum for the type is reached. |
| pub fn wrap_incr(self, interner: DbInterner<'db>) -> Self { |
| self.checked_add(interner, 1).0 |
| } |
| pub fn checked_add(self, interner: DbInterner<'db>, n: u128) -> (Self, bool) { |
| let (size, signed) = self.ty.int_size_and_signed(interner); |
| let (val, oflo) = if signed { |
| let min = size.signed_int_min(); |
| let max = size.signed_int_max(); |
| let val = size.sign_extend(self.val); |
| assert!(n < (i128::MAX as u128)); |
| let n = n as i128; |
| let oflo = val > max - n; |
| let val = if oflo { min + (n - (max - val) - 1) } else { val + n }; |
| // zero the upper bits |
| let val = val as u128; |
| let val = size.truncate(val); |
| (val, oflo) |
| } else { |
| let max = size.unsigned_int_max(); |
| let val = self.val; |
| let oflo = val > max - n; |
| let val = if oflo { n - (max - val) - 1 } else { val + n }; |
| (val, oflo) |
| }; |
| (Self { val, ty: self.ty }, oflo) |
| } |
| } |
| |
| pub trait IntegerTypeExt { |
| fn to_ty<'db>(&self, interner: DbInterner<'db>) -> Ty<'db>; |
| fn initial_discriminant<'db>(&self, interner: DbInterner<'db>) -> Discr<'db>; |
| fn disr_incr<'db>( |
| &self, |
| interner: DbInterner<'db>, |
| val: Option<Discr<'db>>, |
| ) -> Option<Discr<'db>>; |
| } |
| |
| impl IntegerTypeExt for IntegerType { |
| fn to_ty<'db>(&self, interner: DbInterner<'db>) -> Ty<'db> { |
| match self { |
| IntegerType::Pointer(true) => Ty::new(interner, TyKind::Int(IntTy::Isize)), |
| IntegerType::Pointer(false) => Ty::new(interner, TyKind::Uint(UintTy::Usize)), |
| IntegerType::Fixed(i, s) => i.to_ty(interner, *s), |
| } |
| } |
| |
| fn initial_discriminant<'db>(&self, interner: DbInterner<'db>) -> Discr<'db> { |
| Discr { val: 0, ty: self.to_ty(interner) } |
| } |
| |
| fn disr_incr<'db>( |
| &self, |
| interner: DbInterner<'db>, |
| val: Option<Discr<'db>>, |
| ) -> Option<Discr<'db>> { |
| if let Some(val) = val { |
| assert_eq!(self.to_ty(interner), val.ty); |
| let (new, oflo) = val.checked_add(interner, 1); |
| if oflo { None } else { Some(new) } |
| } else { |
| Some(self.initial_discriminant(interner)) |
| } |
| } |
| } |
| |
| pub trait IntegerExt { |
| fn to_ty<'db>(&self, interner: DbInterner<'db>, signed: bool) -> Ty<'db>; |
| fn from_int_ty<C: HasDataLayout>(cx: &C, ity: IntTy) -> Integer; |
| fn from_uint_ty<C: HasDataLayout>(cx: &C, ity: UintTy) -> Integer; |
| fn repr_discr<'db>( |
| interner: DbInterner<'db>, |
| ty: Ty<'db>, |
| repr: &ReprOptions, |
| min: i128, |
| max: i128, |
| ) -> (Integer, bool); |
| } |
| |
| impl IntegerExt for Integer { |
| #[inline] |
| fn to_ty<'db>(&self, interner: DbInterner<'db>, signed: bool) -> Ty<'db> { |
| use Integer::*; |
| match (*self, signed) { |
| (I8, false) => Ty::new(interner, TyKind::Uint(UintTy::U8)), |
| (I16, false) => Ty::new(interner, TyKind::Uint(UintTy::U16)), |
| (I32, false) => Ty::new(interner, TyKind::Uint(UintTy::U32)), |
| (I64, false) => Ty::new(interner, TyKind::Uint(UintTy::U64)), |
| (I128, false) => Ty::new(interner, TyKind::Uint(UintTy::U128)), |
| (I8, true) => Ty::new(interner, TyKind::Int(IntTy::I8)), |
| (I16, true) => Ty::new(interner, TyKind::Int(IntTy::I16)), |
| (I32, true) => Ty::new(interner, TyKind::Int(IntTy::I32)), |
| (I64, true) => Ty::new(interner, TyKind::Int(IntTy::I64)), |
| (I128, true) => Ty::new(interner, TyKind::Int(IntTy::I128)), |
| } |
| } |
| |
| fn from_int_ty<C: HasDataLayout>(cx: &C, ity: IntTy) -> Integer { |
| use Integer::*; |
| match ity { |
| IntTy::I8 => I8, |
| IntTy::I16 => I16, |
| IntTy::I32 => I32, |
| IntTy::I64 => I64, |
| IntTy::I128 => I128, |
| IntTy::Isize => cx.data_layout().ptr_sized_integer(), |
| } |
| } |
| fn from_uint_ty<C: HasDataLayout>(cx: &C, ity: UintTy) -> Integer { |
| use Integer::*; |
| match ity { |
| UintTy::U8 => I8, |
| UintTy::U16 => I16, |
| UintTy::U32 => I32, |
| UintTy::U64 => I64, |
| UintTy::U128 => I128, |
| UintTy::Usize => cx.data_layout().ptr_sized_integer(), |
| } |
| } |
| |
| /// Finds the appropriate Integer type and signedness for the given |
| /// signed discriminant range and `#[repr]` attribute. |
| /// N.B.: `u128` values above `i128::MAX` will be treated as signed, but |
| /// that shouldn't affect anything, other than maybe debuginfo. |
| fn repr_discr<'db>( |
| interner: DbInterner<'db>, |
| ty: Ty<'db>, |
| repr: &ReprOptions, |
| min: i128, |
| max: i128, |
| ) -> (Integer, bool) { |
| // Theoretically, negative values could be larger in unsigned representation |
| // than the unsigned representation of the signed minimum. However, if there |
| // are any negative values, the only valid unsigned representation is u128 |
| // which can fit all i128 values, so the result remains unaffected. |
| let unsigned_fit = Integer::fit_unsigned(std::cmp::max(min as u128, max as u128)); |
| let signed_fit = std::cmp::max(Integer::fit_signed(min), Integer::fit_signed(max)); |
| |
| if let Some(ity) = repr.int { |
| let discr = Integer::from_attr(&interner, ity); |
| let fit = if ity.is_signed() { signed_fit } else { unsigned_fit }; |
| if discr < fit { |
| panic!( |
| "Integer::repr_discr: `#[repr]` hint too small for \ |
| discriminant range of enum `{ty:?}`" |
| ) |
| } |
| return (discr, ity.is_signed()); |
| } |
| |
| let at_least = if repr.c() { |
| // This is usually I32, however it can be different on some platforms, |
| // notably hexagon and arm-none/thumb-none |
| interner.data_layout().c_enum_min_size |
| } else { |
| // repr(Rust) enums try to be as small as possible |
| Integer::I8 |
| }; |
| |
| // If there are no negative values, we can use the unsigned fit. |
| if min >= 0 { |
| (std::cmp::max(unsigned_fit, at_least), false) |
| } else { |
| (std::cmp::max(signed_fit, at_least), true) |
| } |
| } |
| } |
| |
| pub trait FloatExt { |
| fn to_ty<'db>(&self, interner: DbInterner<'db>) -> Ty<'db>; |
| fn from_float_ty(fty: FloatTy) -> Self; |
| } |
| |
| impl FloatExt for Float { |
| #[inline] |
| fn to_ty<'db>(&self, interner: DbInterner<'db>) -> Ty<'db> { |
| use Float::*; |
| match *self { |
| F16 => Ty::new(interner, TyKind::Float(FloatTy::F16)), |
| F32 => Ty::new(interner, TyKind::Float(FloatTy::F32)), |
| F64 => Ty::new(interner, TyKind::Float(FloatTy::F64)), |
| F128 => Ty::new(interner, TyKind::Float(FloatTy::F128)), |
| } |
| } |
| |
| fn from_float_ty(fty: FloatTy) -> Self { |
| use Float::*; |
| match fty { |
| FloatTy::F16 => F16, |
| FloatTy::F32 => F32, |
| FloatTy::F64 => F64, |
| FloatTy::F128 => F128, |
| } |
| } |
| } |
| |
| pub trait PrimitiveExt { |
| fn to_ty<'db>(&self, interner: DbInterner<'db>) -> Ty<'db>; |
| fn to_int_ty<'db>(&self, interner: DbInterner<'db>) -> Ty<'db>; |
| } |
| |
| impl PrimitiveExt for Primitive { |
| #[inline] |
| fn to_ty<'db>(&self, interner: DbInterner<'db>) -> Ty<'db> { |
| match *self { |
| Primitive::Int(i, signed) => i.to_ty(interner, signed), |
| Primitive::Float(f) => f.to_ty(interner), |
| Primitive::Pointer(_) => Ty::new( |
| interner, |
| TyKind::RawPtr( |
| Ty::new(interner, TyKind::Tuple(Default::default())), |
| rustc_ast_ir::Mutability::Mut, |
| ), |
| ), |
| } |
| } |
| |
| /// Return an *integer* type matching this primitive. |
| /// Useful in particular when dealing with enum discriminants. |
| #[inline] |
| fn to_int_ty<'db>(&self, interner: DbInterner<'db>) -> Ty<'db> { |
| match *self { |
| Primitive::Int(i, signed) => i.to_ty(interner, signed), |
| Primitive::Pointer(_) => { |
| let signed = false; |
| interner.data_layout().ptr_sized_integer().to_ty(interner, signed) |
| } |
| Primitive::Float(_) => panic!("floats do not have an int type"), |
| } |
| } |
| } |
| |
| impl<'db> HasDataLayout for DbInterner<'db> { |
| fn data_layout(&self) -> &rustc_abi::TargetDataLayout { |
| unimplemented!() |
| } |
| } |
| |
| pub trait CoroutineArgsExt<'db> { |
| fn discr_ty(&self, interner: DbInterner<'db>) -> Ty<'db>; |
| } |
| |
| impl<'db> CoroutineArgsExt<'db> for CoroutineArgs<DbInterner<'db>> { |
| /// The type of the state discriminant used in the coroutine type. |
| #[inline] |
| fn discr_ty(&self, interner: DbInterner<'db>) -> Ty<'db> { |
| Ty::new(interner, TyKind::Uint(UintTy::U32)) |
| } |
| } |
| |
| /// Finds the max universe present |
| pub struct MaxUniverse { |
| max_universe: UniverseIndex, |
| } |
| |
| impl Default for MaxUniverse { |
| fn default() -> Self { |
| Self::new() |
| } |
| } |
| |
| impl MaxUniverse { |
| pub fn new() -> Self { |
| MaxUniverse { max_universe: UniverseIndex::ROOT } |
| } |
| |
| pub fn max_universe(self) -> UniverseIndex { |
| self.max_universe |
| } |
| } |
| |
| impl<'db> TypeVisitor<DbInterner<'db>> for MaxUniverse { |
| type Result = (); |
| |
| fn visit_ty(&mut self, t: Ty<'db>) { |
| if let TyKind::Placeholder(placeholder) = t.kind() { |
| self.max_universe = UniverseIndex::from_u32( |
| self.max_universe.as_u32().max(placeholder.universe.as_u32()), |
| ); |
| } |
| |
| t.super_visit_with(self) |
| } |
| |
| fn visit_const(&mut self, c: Const<'db>) { |
| if let ConstKind::Placeholder(placeholder) = c.kind() { |
| self.max_universe = UniverseIndex::from_u32( |
| self.max_universe.as_u32().max(placeholder.universe.as_u32()), |
| ); |
| } |
| |
| c.super_visit_with(self) |
| } |
| |
| fn visit_region(&mut self, r: Region<'db>) { |
| if let RegionKind::RePlaceholder(placeholder) = r.kind() { |
| self.max_universe = UniverseIndex::from_u32( |
| self.max_universe.as_u32().max(placeholder.universe.as_u32()), |
| ); |
| } |
| } |
| } |
| |
| pub struct BottomUpFolder<'db, F, G, H> |
| where |
| F: FnMut(Ty<'db>) -> Ty<'db>, |
| G: FnMut(Region<'db>) -> Region<'db>, |
| H: FnMut(Const<'db>) -> Const<'db>, |
| { |
| pub interner: DbInterner<'db>, |
| pub ty_op: F, |
| pub lt_op: G, |
| pub ct_op: H, |
| } |
| |
| impl<'db, F, G, H> TypeFolder<DbInterner<'db>> for BottomUpFolder<'db, F, G, H> |
| where |
| F: FnMut(Ty<'db>) -> Ty<'db>, |
| G: FnMut(Region<'db>) -> Region<'db>, |
| H: FnMut(Const<'db>) -> Const<'db>, |
| { |
| fn cx(&self) -> DbInterner<'db> { |
| self.interner |
| } |
| |
| fn fold_ty(&mut self, ty: Ty<'db>) -> Ty<'db> { |
| let t = ty.super_fold_with(self); |
| (self.ty_op)(t) |
| } |
| |
| fn fold_region(&mut self, r: Region<'db>) -> Region<'db> { |
| // This one is a little different, because `super_fold_with` is not |
| // implemented on non-recursive `Region`. |
| (self.lt_op)(r) |
| } |
| |
| fn fold_const(&mut self, ct: Const<'db>) -> Const<'db> { |
| let ct = ct.super_fold_with(self); |
| (self.ct_op)(ct) |
| } |
| } |
| |
| pub(crate) fn for_trait_impls( |
| db: &dyn HirDatabase, |
| krate: Crate, |
| block: Option<BlockId>, |
| trait_id: hir_def::TraitId, |
| self_ty_fp: Option<TyFingerprint>, |
| mut f: impl FnMut(&TraitImpls) -> ControlFlow<()>, |
| ) -> ControlFlow<()> { |
| // Note: Since we're using `impls_for_trait` and `impl_provided_for`, |
| // only impls where the trait can be resolved should ever reach Chalk. |
| // `impl_datum` relies on that and will panic if the trait can't be resolved. |
| let in_self_and_deps = db.trait_impls_in_deps(krate); |
| let trait_module = trait_id.module(db); |
| let type_module = match self_ty_fp { |
| Some(TyFingerprint::Adt(adt_id)) => Some(adt_id.module(db)), |
| Some(TyFingerprint::ForeignType(type_id)) => Some(type_id.module(db)), |
| Some(TyFingerprint::Dyn(trait_id)) => Some(trait_id.module(db)), |
| _ => None, |
| }; |
| |
| let mut def_blocks = |
| [trait_module.containing_block(), type_module.and_then(|it| it.containing_block())]; |
| |
| let block_impls = iter::successors(block, |&block_id| { |
| cov_mark::hit!(block_local_impls); |
| block_id.loc(db).module.containing_block() |
| }) |
| .inspect(|&block_id| { |
| // make sure we don't search the same block twice |
| def_blocks.iter_mut().for_each(|block| { |
| if *block == Some(block_id) { |
| *block = None; |
| } |
| }); |
| }) |
| .filter_map(|block_id| db.trait_impls_in_block(block_id)); |
| for it in in_self_and_deps.iter().map(ops::Deref::deref) { |
| f(it)?; |
| } |
| for it in block_impls { |
| f(&it)?; |
| } |
| for it in def_blocks.into_iter().flatten().filter_map(|it| db.trait_impls_in_block(it)) { |
| f(&it)?; |
| } |
| ControlFlow::Continue(()) |
| } |
| |
| // FIXME(next-trait-solver): uplift |
| pub fn sizedness_constraint_for_ty<'db>( |
| interner: DbInterner<'db>, |
| sizedness: SizedTraitKind, |
| ty: Ty<'db>, |
| ) -> Option<Ty<'db>> { |
| use rustc_type_ir::TyKind::*; |
| |
| match ty.kind() { |
| // these are always sized |
| Bool | Char | Int(..) | Uint(..) | Float(..) | RawPtr(..) | Ref(..) | FnDef(..) |
| | FnPtr(..) | Array(..) | Closure(..) | CoroutineClosure(..) | Coroutine(..) |
| | CoroutineWitness(..) | Never => None, |
| |
| // these are never sized |
| Str | Slice(..) | Dynamic(_, _) => match sizedness { |
| // Never `Sized` |
| SizedTraitKind::Sized => Some(ty), |
| // Always `MetaSized` |
| SizedTraitKind::MetaSized => None, |
| }, |
| |
| // Maybe `Sized` or `MetaSized` |
| Param(..) | Alias(..) | Error(_) => Some(ty), |
| |
| // We cannot instantiate the binder, so just return the *original* type back, |
| // but only if the inner type has a sized constraint. Thus we skip the binder, |
| // but don't actually use the result from `sized_constraint_for_ty`. |
| UnsafeBinder(inner_ty) => { |
| sizedness_constraint_for_ty(interner, sizedness, inner_ty.skip_binder()).map(|_| ty) |
| } |
| |
| // Never `MetaSized` or `Sized` |
| Foreign(..) => Some(ty), |
| |
| // Recursive cases |
| Pat(ty, _) => sizedness_constraint_for_ty(interner, sizedness, ty), |
| |
| Tuple(tys) => tys |
| .into_iter() |
| .next_back() |
| .and_then(|ty| sizedness_constraint_for_ty(interner, sizedness, ty)), |
| |
| Adt(adt, args) => { |
| let tail_ty = |
| EarlyBinder::bind(adt.all_field_tys(interner).skip_binder().into_iter().last()?) |
| .instantiate(interner, args); |
| sizedness_constraint_for_ty(interner, sizedness, tail_ty) |
| } |
| |
| Placeholder(..) | Bound(..) | Infer(..) => { |
| panic!("unexpected type `{ty:?}` in sizedness_constraint_for_ty") |
| } |
| } |
| } |
| |
| pub fn apply_args_to_binder<'db, T: TypeFoldable<DbInterner<'db>>>( |
| b: Binder<'db, T>, |
| args: GenericArgs<'db>, |
| interner: DbInterner<'db>, |
| ) -> T { |
| let types = &mut |ty: BoundTy| args.as_slice()[ty.var.index()].expect_ty(); |
| let regions = &mut |region: BoundRegion| args.as_slice()[region.var.index()].expect_region(); |
| let consts = &mut |const_: BoundConst| args.as_slice()[const_.var.index()].expect_const(); |
| let mut instantiate = BoundVarReplacer::new(interner, FnMutDelegate { types, regions, consts }); |
| b.skip_binder().fold_with(&mut instantiate) |
| } |
| |
| pub fn explicit_item_bounds<'db>( |
| interner: DbInterner<'db>, |
| def_id: SolverDefId, |
| ) -> EarlyBinder<'db, Clauses<'db>> { |
| let db = interner.db(); |
| match def_id { |
| SolverDefId::TypeAliasId(type_alias) => { |
| // Lower bounds -- we could/should maybe move this to a separate query in `lower` |
| let type_alias_data = db.type_alias_signature(type_alias); |
| let resolver = hir_def::resolver::HasResolver::resolver(type_alias, db); |
| let mut ctx = TyLoweringContext::new( |
| db, |
| &resolver, |
| &type_alias_data.store, |
| type_alias.into(), |
| LifetimeElisionKind::AnonymousReportError, |
| ); |
| |
| let item_args = GenericArgs::identity_for_item(interner, def_id); |
| let interner_ty = Ty::new_projection_from_args(interner, def_id, item_args); |
| |
| let mut bounds = Vec::new(); |
| for bound in &type_alias_data.bounds { |
| ctx.lower_type_bound(bound, interner_ty, false).for_each(|pred| { |
| bounds.push(pred); |
| }); |
| } |
| |
| if !ctx.unsized_types.contains(&interner_ty) { |
| let sized_trait = LangItem::Sized |
| .resolve_trait(ctx.db, interner.krate.expect("Must have interner.krate")); |
| let sized_bound = sized_trait.map(|trait_id| { |
| let trait_ref = TraitRef::new_from_args( |
| interner, |
| trait_id.into(), |
| GenericArgs::new_from_iter(interner, [interner_ty.into()]), |
| ); |
| Clause(Predicate::new( |
| interner, |
| Binder::dummy(rustc_type_ir::PredicateKind::Clause( |
| rustc_type_ir::ClauseKind::Trait(TraitPredicate { |
| trait_ref, |
| polarity: rustc_type_ir::PredicatePolarity::Positive, |
| }), |
| )), |
| )) |
| }); |
| bounds.extend(sized_bound); |
| bounds.shrink_to_fit(); |
| } |
| |
| rustc_type_ir::EarlyBinder::bind(Clauses::new_from_iter(interner, bounds)) |
| } |
| SolverDefId::InternedOpaqueTyId(id) => { |
| let full_id = db.lookup_intern_impl_trait_id(id); |
| match full_id { |
| crate::ImplTraitId::ReturnTypeImplTrait(func, idx) => { |
| let datas = db |
| .return_type_impl_traits(func) |
| .expect("impl trait id without impl traits"); |
| let datas = (*datas).as_ref().skip_binder(); |
| let data = &datas.impl_traits[Idx::from_raw(idx.into_raw())]; |
| EarlyBinder::bind(Clauses::new_from_iter(interner, data.predicates.clone())) |
| } |
| crate::ImplTraitId::TypeAliasImplTrait(alias, idx) => { |
| let datas = db |
| .type_alias_impl_traits(alias) |
| .expect("impl trait id without impl traits"); |
| let datas = (*datas).as_ref().skip_binder(); |
| let data = &datas.impl_traits[Idx::from_raw(idx.into_raw())]; |
| EarlyBinder::bind(Clauses::new_from_iter(interner, data.predicates.clone())) |
| } |
| } |
| } |
| _ => panic!("Unexpected GenericDefId"), |
| } |
| } |
| |
| pub struct ContainsTypeErrors; |
| |
| impl<'db> TypeVisitor<DbInterner<'db>> for ContainsTypeErrors { |
| type Result = ControlFlow<()>; |
| |
| fn visit_ty(&mut self, t: Ty<'db>) -> Self::Result { |
| match t.kind() { |
| rustc_type_ir::TyKind::Error(_) => ControlFlow::Break(()), |
| _ => t.super_visit_with(self), |
| } |
| } |
| } |
| |
| /// The inverse of [`BoundVarReplacer`]: replaces placeholders with the bound vars from which they came. |
| pub struct PlaceholderReplacer<'a, 'db> { |
| infcx: &'a InferCtxt<'db>, |
| mapped_regions: FxIndexMap<PlaceholderRegion, BoundRegion>, |
| mapped_types: FxIndexMap<Placeholder<BoundTy>, BoundTy>, |
| mapped_consts: FxIndexMap<PlaceholderConst, BoundConst>, |
| universe_indices: &'a [Option<UniverseIndex>], |
| current_index: DebruijnIndex, |
| } |
| |
| impl<'a, 'db> PlaceholderReplacer<'a, 'db> { |
| pub fn replace_placeholders<T: TypeFoldable<DbInterner<'db>>>( |
| infcx: &'a InferCtxt<'db>, |
| mapped_regions: FxIndexMap<PlaceholderRegion, BoundRegion>, |
| mapped_types: FxIndexMap<Placeholder<BoundTy>, BoundTy>, |
| mapped_consts: FxIndexMap<PlaceholderConst, BoundConst>, |
| universe_indices: &'a [Option<UniverseIndex>], |
| value: T, |
| ) -> T { |
| let mut replacer = PlaceholderReplacer { |
| infcx, |
| mapped_regions, |
| mapped_types, |
| mapped_consts, |
| universe_indices, |
| current_index: INNERMOST, |
| }; |
| value.fold_with(&mut replacer) |
| } |
| } |
| |
| impl<'db> TypeFolder<DbInterner<'db>> for PlaceholderReplacer<'_, 'db> { |
| fn cx(&self) -> DbInterner<'db> { |
| self.infcx.interner |
| } |
| |
| fn fold_binder<T: TypeFoldable<DbInterner<'db>>>( |
| &mut self, |
| t: Binder<'db, T>, |
| ) -> Binder<'db, T> { |
| if !t.has_placeholders() && !t.has_infer() { |
| return t; |
| } |
| self.current_index.shift_in(1); |
| let t = t.super_fold_with(self); |
| self.current_index.shift_out(1); |
| t |
| } |
| |
| fn fold_region(&mut self, r0: Region<'db>) -> Region<'db> { |
| let r1 = match r0.kind() { |
| RegionKind::ReVar(vid) => self |
| .infcx |
| .inner |
| .borrow_mut() |
| .unwrap_region_constraints() |
| .opportunistic_resolve_var(self.infcx.interner, vid), |
| _ => r0, |
| }; |
| |
| let r2 = match r1.kind() { |
| RegionKind::RePlaceholder(p) => { |
| let replace_var = self.mapped_regions.get(&p); |
| match replace_var { |
| Some(replace_var) => { |
| let index = self |
| .universe_indices |
| .iter() |
| .position(|u| matches!(u, Some(pu) if *pu == p.universe)) |
| .unwrap_or_else(|| panic!("Unexpected placeholder universe.")); |
| let db = DebruijnIndex::from_usize( |
| self.universe_indices.len() - index + self.current_index.as_usize() - 1, |
| ); |
| Region::new_bound(self.cx(), db, *replace_var) |
| } |
| None => r1, |
| } |
| } |
| _ => r1, |
| }; |
| |
| tracing::debug!(?r0, ?r1, ?r2, "fold_region"); |
| |
| r2 |
| } |
| |
| fn fold_ty(&mut self, ty: Ty<'db>) -> Ty<'db> { |
| let ty = self.infcx.shallow_resolve(ty); |
| match ty.kind() { |
| TyKind::Placeholder(p) => { |
| let replace_var = self.mapped_types.get(&p); |
| match replace_var { |
| Some(replace_var) => { |
| let index = self |
| .universe_indices |
| .iter() |
| .position(|u| matches!(u, Some(pu) if *pu == p.universe)) |
| .unwrap_or_else(|| panic!("Unexpected placeholder universe.")); |
| let db = DebruijnIndex::from_usize( |
| self.universe_indices.len() - index + self.current_index.as_usize() - 1, |
| ); |
| Ty::new_bound(self.infcx.interner, db, *replace_var) |
| } |
| None => { |
| if ty.has_infer() { |
| ty.super_fold_with(self) |
| } else { |
| ty |
| } |
| } |
| } |
| } |
| |
| _ if ty.has_placeholders() || ty.has_infer() => ty.super_fold_with(self), |
| _ => ty, |
| } |
| } |
| |
| fn fold_const(&mut self, ct: Const<'db>) -> Const<'db> { |
| let ct = self.infcx.shallow_resolve_const(ct); |
| if let ConstKind::Placeholder(p) = ct.kind() { |
| let replace_var = self.mapped_consts.get(&p); |
| match replace_var { |
| Some(replace_var) => { |
| let index = self |
| .universe_indices |
| .iter() |
| .position(|u| matches!(u, Some(pu) if *pu == p.universe)) |
| .unwrap_or_else(|| panic!("Unexpected placeholder universe.")); |
| let db = DebruijnIndex::from_usize( |
| self.universe_indices.len() - index + self.current_index.as_usize() - 1, |
| ); |
| Const::new_bound(self.infcx.interner, db, *replace_var) |
| } |
| None => { |
| if ct.has_infer() { |
| ct.super_fold_with(self) |
| } else { |
| ct |
| } |
| } |
| } |
| } else { |
| ct.super_fold_with(self) |
| } |
| } |
| } |
| |
| pub fn sizedness_fast_path<'db>( |
| tcx: DbInterner<'db>, |
| predicate: Predicate<'db>, |
| param_env: ParamEnv<'db>, |
| ) -> bool { |
| // Proving `Sized`/`MetaSized`, very often on "obviously sized" types like |
| // `&T`, accounts for about 60% percentage of the predicates we have to prove. No need to |
| // canonicalize and all that for such cases. |
| if let PredicateKind::Clause(ClauseKind::Trait(trait_pred)) = predicate.kind().skip_binder() |
| && trait_pred.polarity == PredicatePolarity::Positive |
| { |
| let sizedness = match tcx.as_trait_lang_item(trait_pred.def_id()) { |
| Some(SolverTraitLangItem::Sized) => SizedTraitKind::Sized, |
| Some(SolverTraitLangItem::MetaSized) => SizedTraitKind::MetaSized, |
| _ => return false, |
| }; |
| |
| // FIXME(sized_hierarchy): this temporarily reverts the `sized_hierarchy` feature |
| // while a proper fix for `tests/ui/sized-hierarchy/incomplete-inference-issue-143992.rs` |
| // is pending a proper fix |
| if matches!(sizedness, SizedTraitKind::MetaSized) { |
| return true; |
| } |
| |
| if trait_pred.self_ty().has_trivial_sizedness(tcx, sizedness) { |
| tracing::debug!("fast path -- trivial sizedness"); |
| return true; |
| } |
| |
| if matches!(trait_pred.self_ty().kind(), TyKind::Param(_) | TyKind::Placeholder(_)) { |
| for clause in param_env.caller_bounds().iter() { |
| if let ClauseKind::Trait(clause_pred) = clause.kind().skip_binder() |
| && clause_pred.polarity == PredicatePolarity::Positive |
| && clause_pred.self_ty() == trait_pred.self_ty() |
| && (clause_pred.def_id() == trait_pred.def_id() |
| || (sizedness == SizedTraitKind::MetaSized |
| && tcx.is_trait_lang_item( |
| clause_pred.def_id(), |
| SolverTraitLangItem::Sized, |
| ))) |
| { |
| return true; |
| } |
| } |
| } |
| } |
| |
| false |
| } |
