| //! This module contains `TyKind` and its major components. |
| |
| #![allow(rustc::usage_of_ty_tykind)] |
| |
| use crate::infer::canonical::Canonical; |
| use crate::ty::subst::{GenericArg, InternalSubsts, SubstsRef}; |
| use crate::ty::visit::ValidateBoundVars; |
| use crate::ty::InferTy::*; |
| use crate::ty::{ |
| self, AdtDef, DefIdTree, Discr, FallibleTypeFolder, Term, Ty, TyCtxt, TypeFlags, TypeFoldable, |
| TypeSuperFoldable, TypeSuperVisitable, TypeVisitable, TypeVisitableExt, TypeVisitor, |
| }; |
| use crate::ty::{List, ParamEnv}; |
| use hir::def::DefKind; |
| use polonius_engine::Atom; |
| use rustc_data_structures::captures::Captures; |
| use rustc_data_structures::intern::Interned; |
| use rustc_hir as hir; |
| use rustc_hir::def_id::DefId; |
| use rustc_hir::LangItem; |
| use rustc_index::vec::Idx; |
| use rustc_macros::HashStable; |
| use rustc_span::symbol::{kw, sym, Symbol}; |
| use rustc_span::Span; |
| use rustc_target::abi::VariantIdx; |
| use rustc_target::spec::abi; |
| use std::borrow::Cow; |
| use std::cmp::Ordering; |
| use std::fmt; |
| use std::marker::PhantomData; |
| use std::ops::{ControlFlow, Deref, Range}; |
| use ty::util::IntTypeExt; |
| |
| use rustc_type_ir::sty::TyKind::*; |
| use rustc_type_ir::RegionKind as IrRegionKind; |
| use rustc_type_ir::TyKind as IrTyKind; |
| |
| // Re-export the `TyKind` from `rustc_type_ir` here for convenience |
| #[rustc_diagnostic_item = "TyKind"] |
| pub type TyKind<'tcx> = IrTyKind<TyCtxt<'tcx>>; |
| pub type RegionKind<'tcx> = IrRegionKind<TyCtxt<'tcx>>; |
| |
| #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] |
| #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)] |
| pub struct TypeAndMut<'tcx> { |
| pub ty: Ty<'tcx>, |
| pub mutbl: hir::Mutability, |
| } |
| |
| #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash, TyEncodable, TyDecodable, Copy)] |
| #[derive(HashStable)] |
| /// A "free" region `fr` can be interpreted as "some region |
| /// at least as big as the scope `fr.scope`". |
| pub struct FreeRegion { |
| pub scope: DefId, |
| pub bound_region: BoundRegionKind, |
| } |
| |
| #[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash, TyEncodable, TyDecodable, Copy)] |
| #[derive(HashStable)] |
| pub enum BoundRegionKind { |
| /// An anonymous region parameter for a given fn (&T) |
| BrAnon(u32, Option<Span>), |
| |
| /// Named region parameters for functions (a in &'a T) |
| /// |
| /// The `DefId` is needed to distinguish free regions in |
| /// the event of shadowing. |
| BrNamed(DefId, Symbol), |
| |
| /// Anonymous region for the implicit env pointer parameter |
| /// to a closure |
| BrEnv, |
| } |
| |
| #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, Debug, PartialOrd, Ord)] |
| #[derive(HashStable)] |
| pub struct BoundRegion { |
| pub var: BoundVar, |
| pub kind: BoundRegionKind, |
| } |
| |
| impl BoundRegionKind { |
| pub fn is_named(&self) -> bool { |
| match *self { |
| BoundRegionKind::BrNamed(_, name) => { |
| name != kw::UnderscoreLifetime && name != kw::Empty |
| } |
| _ => false, |
| } |
| } |
| |
| pub fn get_name(&self) -> Option<Symbol> { |
| if self.is_named() { |
| match *self { |
| BoundRegionKind::BrNamed(_, name) => return Some(name), |
| _ => unreachable!(), |
| } |
| } |
| |
| None |
| } |
| |
| pub fn get_id(&self) -> Option<DefId> { |
| match *self { |
| BoundRegionKind::BrNamed(id, _) => return Some(id), |
| _ => None, |
| } |
| } |
| |
| pub fn expect_anon(&self) -> u32 { |
| match *self { |
| BoundRegionKind::BrNamed(_, _) | BoundRegionKind::BrEnv => { |
| bug!("expected anon region: {self:?}") |
| } |
| BoundRegionKind::BrAnon(idx, _) => idx, |
| } |
| } |
| } |
| |
| pub trait Article { |
| fn article(&self) -> &'static str; |
| } |
| |
| impl<'tcx> Article for TyKind<'tcx> { |
| /// Get the article ("a" or "an") to use with this type. |
| fn article(&self) -> &'static str { |
| match self { |
| Int(_) | Float(_) | Array(_, _) => "an", |
| Adt(def, _) if def.is_enum() => "an", |
| // This should never happen, but ICEing and causing the user's code |
| // to not compile felt too harsh. |
| Error(_) => "a", |
| _ => "a", |
| } |
| } |
| } |
| |
| // `TyKind` is used a lot. Make sure it doesn't unintentionally get bigger. |
| #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))] |
| static_assert_size!(TyKind<'_>, 32); |
| |
| /// A closure can be modeled as a struct that looks like: |
| /// ```ignore (illustrative) |
| /// struct Closure<'l0...'li, T0...Tj, CK, CS, U>(...U); |
| /// ``` |
| /// where: |
| /// |
| /// - 'l0...'li and T0...Tj are the generic parameters |
| /// in scope on the function that defined the closure, |
| /// - CK represents the *closure kind* (Fn vs FnMut vs FnOnce). This |
| /// is rather hackily encoded via a scalar type. See |
| /// `Ty::to_opt_closure_kind` for details. |
| /// - CS represents the *closure signature*, representing as a `fn()` |
| /// type. For example, `fn(u32, u32) -> u32` would mean that the closure |
| /// implements `CK<(u32, u32), Output = u32>`, where `CK` is the trait |
| /// specified above. |
| /// - U is a type parameter representing the types of its upvars, tupled up |
| /// (borrowed, if appropriate; that is, if a U field represents a by-ref upvar, |
| /// and the up-var has the type `Foo`, then that field of U will be `&Foo`). |
| /// |
| /// So, for example, given this function: |
| /// ```ignore (illustrative) |
| /// fn foo<'a, T>(data: &'a mut T) { |
| /// do(|| data.count += 1) |
| /// } |
| /// ``` |
| /// the type of the closure would be something like: |
| /// ```ignore (illustrative) |
| /// struct Closure<'a, T, U>(...U); |
| /// ``` |
| /// Note that the type of the upvar is not specified in the struct. |
| /// You may wonder how the impl would then be able to use the upvar, |
| /// if it doesn't know it's type? The answer is that the impl is |
| /// (conceptually) not fully generic over Closure but rather tied to |
| /// instances with the expected upvar types: |
| /// ```ignore (illustrative) |
| /// impl<'b, 'a, T> FnMut() for Closure<'a, T, (&'b mut &'a mut T,)> { |
| /// ... |
| /// } |
| /// ``` |
| /// You can see that the *impl* fully specified the type of the upvar |
| /// and thus knows full well that `data` has type `&'b mut &'a mut T`. |
| /// (Here, I am assuming that `data` is mut-borrowed.) |
| /// |
| /// Now, the last question you may ask is: Why include the upvar types |
| /// in an extra type parameter? The reason for this design is that the |
| /// upvar types can reference lifetimes that are internal to the |
| /// creating function. In my example above, for example, the lifetime |
| /// `'b` represents the scope of the closure itself; this is some |
| /// subset of `foo`, probably just the scope of the call to the to |
| /// `do()`. If we just had the lifetime/type parameters from the |
| /// enclosing function, we couldn't name this lifetime `'b`. Note that |
| /// there can also be lifetimes in the types of the upvars themselves, |
| /// if one of them happens to be a reference to something that the |
| /// creating fn owns. |
| /// |
| /// OK, you say, so why not create a more minimal set of parameters |
| /// that just includes the extra lifetime parameters? The answer is |
| /// primarily that it would be hard --- we don't know at the time when |
| /// we create the closure type what the full types of the upvars are, |
| /// nor do we know which are borrowed and which are not. In this |
| /// design, we can just supply a fresh type parameter and figure that |
| /// out later. |
| /// |
| /// All right, you say, but why include the type parameters from the |
| /// original function then? The answer is that codegen may need them |
| /// when monomorphizing, and they may not appear in the upvars. A |
| /// closure could capture no variables but still make use of some |
| /// in-scope type parameter with a bound (e.g., if our example above |
| /// had an extra `U: Default`, and the closure called `U::default()`). |
| /// |
| /// There is another reason. This design (implicitly) prohibits |
| /// closures from capturing themselves (except via a trait |
| /// object). This simplifies closure inference considerably, since it |
| /// means that when we infer the kind of a closure or its upvars, we |
| /// don't have to handle cycles where the decisions we make for |
| /// closure C wind up influencing the decisions we ought to make for |
| /// closure C (which would then require fixed point iteration to |
| /// handle). Plus it fixes an ICE. :P |
| /// |
| /// ## Generators |
| /// |
| /// Generators are handled similarly in `GeneratorSubsts`. The set of |
| /// type parameters is similar, but `CK` and `CS` are replaced by the |
| /// following type parameters: |
| /// |
| /// * `GS`: The generator's "resume type", which is the type of the |
| /// argument passed to `resume`, and the type of `yield` expressions |
| /// inside the generator. |
| /// * `GY`: The "yield type", which is the type of values passed to |
| /// `yield` inside the generator. |
| /// * `GR`: The "return type", which is the type of value returned upon |
| /// completion of the generator. |
| /// * `GW`: The "generator witness". |
| #[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable, Lift)] |
| pub struct ClosureSubsts<'tcx> { |
| /// Lifetime and type parameters from the enclosing function, |
| /// concatenated with a tuple containing the types of the upvars. |
| /// |
| /// These are separated out because codegen wants to pass them around |
| /// when monomorphizing. |
| pub substs: SubstsRef<'tcx>, |
| } |
| |
| /// Struct returned by `split()`. |
| pub struct ClosureSubstsParts<'tcx, T> { |
| pub parent_substs: &'tcx [GenericArg<'tcx>], |
| pub closure_kind_ty: T, |
| pub closure_sig_as_fn_ptr_ty: T, |
| pub tupled_upvars_ty: T, |
| } |
| |
| impl<'tcx> ClosureSubsts<'tcx> { |
| /// Construct `ClosureSubsts` from `ClosureSubstsParts`, containing `Substs` |
| /// for the closure parent, alongside additional closure-specific components. |
| pub fn new( |
| tcx: TyCtxt<'tcx>, |
| parts: ClosureSubstsParts<'tcx, Ty<'tcx>>, |
| ) -> ClosureSubsts<'tcx> { |
| ClosureSubsts { |
| substs: tcx.mk_substs_from_iter( |
| parts.parent_substs.iter().copied().chain( |
| [parts.closure_kind_ty, parts.closure_sig_as_fn_ptr_ty, parts.tupled_upvars_ty] |
| .iter() |
| .map(|&ty| ty.into()), |
| ), |
| ), |
| } |
| } |
| |
| /// Divides the closure substs into their respective components. |
| /// The ordering assumed here must match that used by `ClosureSubsts::new` above. |
| fn split(self) -> ClosureSubstsParts<'tcx, GenericArg<'tcx>> { |
| match self.substs[..] { |
| [ |
| ref parent_substs @ .., |
| closure_kind_ty, |
| closure_sig_as_fn_ptr_ty, |
| tupled_upvars_ty, |
| ] => ClosureSubstsParts { |
| parent_substs, |
| closure_kind_ty, |
| closure_sig_as_fn_ptr_ty, |
| tupled_upvars_ty, |
| }, |
| _ => bug!("closure substs missing synthetics"), |
| } |
| } |
| |
| /// Returns `true` only if enough of the synthetic types are known to |
| /// allow using all of the methods on `ClosureSubsts` without panicking. |
| /// |
| /// Used primarily by `ty::print::pretty` to be able to handle closure |
| /// types that haven't had their synthetic types substituted in. |
| pub fn is_valid(self) -> bool { |
| self.substs.len() >= 3 |
| && matches!(self.split().tupled_upvars_ty.expect_ty().kind(), Tuple(_)) |
| } |
| |
| /// Returns the substitutions of the closure's parent. |
| pub fn parent_substs(self) -> &'tcx [GenericArg<'tcx>] { |
| self.split().parent_substs |
| } |
| |
| /// Returns an iterator over the list of types of captured paths by the closure. |
| /// In case there was a type error in figuring out the types of the captured path, an |
| /// empty iterator is returned. |
| #[inline] |
| pub fn upvar_tys(self) -> impl Iterator<Item = Ty<'tcx>> + 'tcx { |
| match self.tupled_upvars_ty().kind() { |
| TyKind::Error(_) => None, |
| TyKind::Tuple(..) => Some(self.tupled_upvars_ty().tuple_fields()), |
| TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"), |
| ty => bug!("Unexpected representation of upvar types tuple {:?}", ty), |
| } |
| .into_iter() |
| .flatten() |
| } |
| |
| /// Returns the tuple type representing the upvars for this closure. |
| #[inline] |
| pub fn tupled_upvars_ty(self) -> Ty<'tcx> { |
| self.split().tupled_upvars_ty.expect_ty() |
| } |
| |
| /// Returns the closure kind for this closure; may return a type |
| /// variable during inference. To get the closure kind during |
| /// inference, use `infcx.closure_kind(substs)`. |
| pub fn kind_ty(self) -> Ty<'tcx> { |
| self.split().closure_kind_ty.expect_ty() |
| } |
| |
| /// Returns the `fn` pointer type representing the closure signature for this |
| /// closure. |
| // FIXME(eddyb) this should be unnecessary, as the shallowly resolved |
| // type is known at the time of the creation of `ClosureSubsts`, |
| // see `rustc_hir_analysis::check::closure`. |
| pub fn sig_as_fn_ptr_ty(self) -> Ty<'tcx> { |
| self.split().closure_sig_as_fn_ptr_ty.expect_ty() |
| } |
| |
| /// Returns the closure kind for this closure; only usable outside |
| /// of an inference context, because in that context we know that |
| /// there are no type variables. |
| /// |
| /// If you have an inference context, use `infcx.closure_kind()`. |
| pub fn kind(self) -> ty::ClosureKind { |
| self.kind_ty().to_opt_closure_kind().unwrap() |
| } |
| |
| /// Extracts the signature from the closure. |
| pub fn sig(self) -> ty::PolyFnSig<'tcx> { |
| let ty = self.sig_as_fn_ptr_ty(); |
| match ty.kind() { |
| ty::FnPtr(sig) => *sig, |
| _ => bug!("closure_sig_as_fn_ptr_ty is not a fn-ptr: {:?}", ty.kind()), |
| } |
| } |
| |
| pub fn print_as_impl_trait(self) -> ty::print::PrintClosureAsImpl<'tcx> { |
| ty::print::PrintClosureAsImpl { closure: self } |
| } |
| } |
| |
| /// Similar to `ClosureSubsts`; see the above documentation for more. |
| #[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable, Lift)] |
| pub struct GeneratorSubsts<'tcx> { |
| pub substs: SubstsRef<'tcx>, |
| } |
| |
| pub struct GeneratorSubstsParts<'tcx, T> { |
| pub parent_substs: &'tcx [GenericArg<'tcx>], |
| pub resume_ty: T, |
| pub yield_ty: T, |
| pub return_ty: T, |
| pub witness: T, |
| pub tupled_upvars_ty: T, |
| } |
| |
| impl<'tcx> GeneratorSubsts<'tcx> { |
| /// Construct `GeneratorSubsts` from `GeneratorSubstsParts`, containing `Substs` |
| /// for the generator parent, alongside additional generator-specific components. |
| pub fn new( |
| tcx: TyCtxt<'tcx>, |
| parts: GeneratorSubstsParts<'tcx, Ty<'tcx>>, |
| ) -> GeneratorSubsts<'tcx> { |
| GeneratorSubsts { |
| substs: tcx.mk_substs_from_iter( |
| parts.parent_substs.iter().copied().chain( |
| [ |
| parts.resume_ty, |
| parts.yield_ty, |
| parts.return_ty, |
| parts.witness, |
| parts.tupled_upvars_ty, |
| ] |
| .iter() |
| .map(|&ty| ty.into()), |
| ), |
| ), |
| } |
| } |
| |
| /// Divides the generator substs into their respective components. |
| /// The ordering assumed here must match that used by `GeneratorSubsts::new` above. |
| fn split(self) -> GeneratorSubstsParts<'tcx, GenericArg<'tcx>> { |
| match self.substs[..] { |
| [ref parent_substs @ .., resume_ty, yield_ty, return_ty, witness, tupled_upvars_ty] => { |
| GeneratorSubstsParts { |
| parent_substs, |
| resume_ty, |
| yield_ty, |
| return_ty, |
| witness, |
| tupled_upvars_ty, |
| } |
| } |
| _ => bug!("generator substs missing synthetics"), |
| } |
| } |
| |
| /// Returns `true` only if enough of the synthetic types are known to |
| /// allow using all of the methods on `GeneratorSubsts` without panicking. |
| /// |
| /// Used primarily by `ty::print::pretty` to be able to handle generator |
| /// types that haven't had their synthetic types substituted in. |
| pub fn is_valid(self) -> bool { |
| self.substs.len() >= 5 |
| && matches!(self.split().tupled_upvars_ty.expect_ty().kind(), Tuple(_)) |
| } |
| |
| /// Returns the substitutions of the generator's parent. |
| pub fn parent_substs(self) -> &'tcx [GenericArg<'tcx>] { |
| self.split().parent_substs |
| } |
| |
| /// This describes the types that can be contained in a generator. |
| /// It will be a type variable initially and unified in the last stages of typeck of a body. |
| /// It contains a tuple of all the types that could end up on a generator frame. |
| /// The state transformation MIR pass may only produce layouts which mention types |
| /// in this tuple. Upvars are not counted here. |
| pub fn witness(self) -> Ty<'tcx> { |
| self.split().witness.expect_ty() |
| } |
| |
| /// Returns an iterator over the list of types of captured paths by the generator. |
| /// In case there was a type error in figuring out the types of the captured path, an |
| /// empty iterator is returned. |
| #[inline] |
| pub fn upvar_tys(self) -> impl Iterator<Item = Ty<'tcx>> + 'tcx { |
| match self.tupled_upvars_ty().kind() { |
| TyKind::Error(_) => None, |
| TyKind::Tuple(..) => Some(self.tupled_upvars_ty().tuple_fields()), |
| TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"), |
| ty => bug!("Unexpected representation of upvar types tuple {:?}", ty), |
| } |
| .into_iter() |
| .flatten() |
| } |
| |
| /// Returns the tuple type representing the upvars for this generator. |
| #[inline] |
| pub fn tupled_upvars_ty(self) -> Ty<'tcx> { |
| self.split().tupled_upvars_ty.expect_ty() |
| } |
| |
| /// Returns the type representing the resume type of the generator. |
| pub fn resume_ty(self) -> Ty<'tcx> { |
| self.split().resume_ty.expect_ty() |
| } |
| |
| /// Returns the type representing the yield type of the generator. |
| pub fn yield_ty(self) -> Ty<'tcx> { |
| self.split().yield_ty.expect_ty() |
| } |
| |
| /// Returns the type representing the return type of the generator. |
| pub fn return_ty(self) -> Ty<'tcx> { |
| self.split().return_ty.expect_ty() |
| } |
| |
| /// Returns the "generator signature", which consists of its yield |
| /// and return types. |
| /// |
| /// N.B., some bits of the code prefers to see this wrapped in a |
| /// binder, but it never contains bound regions. Probably this |
| /// function should be removed. |
| pub fn poly_sig(self) -> PolyGenSig<'tcx> { |
| ty::Binder::dummy(self.sig()) |
| } |
| |
| /// Returns the "generator signature", which consists of its resume, yield |
| /// and return types. |
| pub fn sig(self) -> GenSig<'tcx> { |
| ty::GenSig { |
| resume_ty: self.resume_ty(), |
| yield_ty: self.yield_ty(), |
| return_ty: self.return_ty(), |
| } |
| } |
| } |
| |
| impl<'tcx> GeneratorSubsts<'tcx> { |
| /// Generator has not been resumed yet. |
| pub const UNRESUMED: usize = 0; |
| /// Generator has returned or is completed. |
| pub const RETURNED: usize = 1; |
| /// Generator has been poisoned. |
| pub const POISONED: usize = 2; |
| |
| const UNRESUMED_NAME: &'static str = "Unresumed"; |
| const RETURNED_NAME: &'static str = "Returned"; |
| const POISONED_NAME: &'static str = "Panicked"; |
| |
| /// The valid variant indices of this generator. |
| #[inline] |
| pub fn variant_range(&self, def_id: DefId, tcx: TyCtxt<'tcx>) -> Range<VariantIdx> { |
| // FIXME requires optimized MIR |
| let num_variants = tcx.generator_layout(def_id).unwrap().variant_fields.len(); |
| VariantIdx::new(0)..VariantIdx::new(num_variants) |
| } |
| |
| /// The discriminant for the given variant. Panics if the `variant_index` is |
| /// out of range. |
| #[inline] |
| pub fn discriminant_for_variant( |
| &self, |
| def_id: DefId, |
| tcx: TyCtxt<'tcx>, |
| variant_index: VariantIdx, |
| ) -> Discr<'tcx> { |
| // Generators don't support explicit discriminant values, so they are |
| // the same as the variant index. |
| assert!(self.variant_range(def_id, tcx).contains(&variant_index)); |
| Discr { val: variant_index.as_usize() as u128, ty: self.discr_ty(tcx) } |
| } |
| |
| /// The set of all discriminants for the generator, enumerated with their |
| /// variant indices. |
| #[inline] |
| pub fn discriminants( |
| self, |
| def_id: DefId, |
| tcx: TyCtxt<'tcx>, |
| ) -> impl Iterator<Item = (VariantIdx, Discr<'tcx>)> + Captures<'tcx> { |
| self.variant_range(def_id, tcx).map(move |index| { |
| (index, Discr { val: index.as_usize() as u128, ty: self.discr_ty(tcx) }) |
| }) |
| } |
| |
| /// Calls `f` with a reference to the name of the enumerator for the given |
| /// variant `v`. |
| pub fn variant_name(v: VariantIdx) -> Cow<'static, str> { |
| match v.as_usize() { |
| Self::UNRESUMED => Cow::from(Self::UNRESUMED_NAME), |
| Self::RETURNED => Cow::from(Self::RETURNED_NAME), |
| Self::POISONED => Cow::from(Self::POISONED_NAME), |
| _ => Cow::from(format!("Suspend{}", v.as_usize() - 3)), |
| } |
| } |
| |
| /// The type of the state discriminant used in the generator type. |
| #[inline] |
| pub fn discr_ty(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
| tcx.types.u32 |
| } |
| |
| /// This returns the types of the MIR locals which had to be stored across suspension points. |
| /// It is calculated in rustc_mir_transform::generator::StateTransform. |
| /// All the types here must be in the tuple in GeneratorInterior. |
| /// |
| /// The locals are grouped by their variant number. Note that some locals may |
| /// be repeated in multiple variants. |
| #[inline] |
| pub fn state_tys( |
| self, |
| def_id: DefId, |
| tcx: TyCtxt<'tcx>, |
| ) -> impl Iterator<Item: Iterator<Item = Ty<'tcx>> + Captures<'tcx>> { |
| let layout = tcx.generator_layout(def_id).unwrap(); |
| layout.variant_fields.iter().map(move |variant| { |
| variant.iter().map(move |field| { |
| ty::EarlyBinder(layout.field_tys[*field].ty).subst(tcx, self.substs) |
| }) |
| }) |
| } |
| |
| /// This is the types of the fields of a generator which are not stored in a |
| /// variant. |
| #[inline] |
| pub fn prefix_tys(self) -> impl Iterator<Item = Ty<'tcx>> { |
| self.upvar_tys() |
| } |
| } |
| |
| #[derive(Debug, Copy, Clone, HashStable)] |
| pub enum UpvarSubsts<'tcx> { |
| Closure(SubstsRef<'tcx>), |
| Generator(SubstsRef<'tcx>), |
| } |
| |
| impl<'tcx> UpvarSubsts<'tcx> { |
| /// Returns an iterator over the list of types of captured paths by the closure/generator. |
| /// In case there was a type error in figuring out the types of the captured path, an |
| /// empty iterator is returned. |
| #[inline] |
| pub fn upvar_tys(self) -> impl Iterator<Item = Ty<'tcx>> + 'tcx { |
| let tupled_tys = match self { |
| UpvarSubsts::Closure(substs) => substs.as_closure().tupled_upvars_ty(), |
| UpvarSubsts::Generator(substs) => substs.as_generator().tupled_upvars_ty(), |
| }; |
| |
| match tupled_tys.kind() { |
| TyKind::Error(_) => None, |
| TyKind::Tuple(..) => Some(self.tupled_upvars_ty().tuple_fields()), |
| TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"), |
| ty => bug!("Unexpected representation of upvar types tuple {:?}", ty), |
| } |
| .into_iter() |
| .flatten() |
| } |
| |
| #[inline] |
| pub fn tupled_upvars_ty(self) -> Ty<'tcx> { |
| match self { |
| UpvarSubsts::Closure(substs) => substs.as_closure().tupled_upvars_ty(), |
| UpvarSubsts::Generator(substs) => substs.as_generator().tupled_upvars_ty(), |
| } |
| } |
| } |
| |
| /// An inline const is modeled like |
| /// ```ignore (illustrative) |
| /// const InlineConst<'l0...'li, T0...Tj, R>: R; |
| /// ``` |
| /// where: |
| /// |
| /// - 'l0...'li and T0...Tj are the generic parameters |
| /// inherited from the item that defined the inline const, |
| /// - R represents the type of the constant. |
| /// |
| /// When the inline const is instantiated, `R` is substituted as the actual inferred |
| /// type of the constant. The reason that `R` is represented as an extra type parameter |
| /// is the same reason that [`ClosureSubsts`] have `CS` and `U` as type parameters: |
| /// inline const can reference lifetimes that are internal to the creating function. |
| #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)] |
| pub struct InlineConstSubsts<'tcx> { |
| /// Generic parameters from the enclosing item, |
| /// concatenated with the inferred type of the constant. |
| pub substs: SubstsRef<'tcx>, |
| } |
| |
| /// Struct returned by `split()`. |
| pub struct InlineConstSubstsParts<'tcx, T> { |
| pub parent_substs: &'tcx [GenericArg<'tcx>], |
| pub ty: T, |
| } |
| |
| impl<'tcx> InlineConstSubsts<'tcx> { |
| /// Construct `InlineConstSubsts` from `InlineConstSubstsParts`. |
| pub fn new( |
| tcx: TyCtxt<'tcx>, |
| parts: InlineConstSubstsParts<'tcx, Ty<'tcx>>, |
| ) -> InlineConstSubsts<'tcx> { |
| InlineConstSubsts { |
| substs: tcx.mk_substs_from_iter( |
| parts.parent_substs.iter().copied().chain(std::iter::once(parts.ty.into())), |
| ), |
| } |
| } |
| |
| /// Divides the inline const substs into their respective components. |
| /// The ordering assumed here must match that used by `InlineConstSubsts::new` above. |
| fn split(self) -> InlineConstSubstsParts<'tcx, GenericArg<'tcx>> { |
| match self.substs[..] { |
| [ref parent_substs @ .., ty] => InlineConstSubstsParts { parent_substs, ty }, |
| _ => bug!("inline const substs missing synthetics"), |
| } |
| } |
| |
| /// Returns the substitutions of the inline const's parent. |
| pub fn parent_substs(self) -> &'tcx [GenericArg<'tcx>] { |
| self.split().parent_substs |
| } |
| |
| /// Returns the type of this inline const. |
| pub fn ty(self) -> Ty<'tcx> { |
| self.split().ty.expect_ty() |
| } |
| } |
| |
| #[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Ord, Eq, Hash, TyEncodable, TyDecodable)] |
| #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)] |
| pub enum ExistentialPredicate<'tcx> { |
| /// E.g., `Iterator`. |
| Trait(ExistentialTraitRef<'tcx>), |
| /// E.g., `Iterator::Item = T`. |
| Projection(ExistentialProjection<'tcx>), |
| /// E.g., `Send`. |
| AutoTrait(DefId), |
| } |
| |
| impl<'tcx> ExistentialPredicate<'tcx> { |
| /// Compares via an ordering that will not change if modules are reordered or other changes are |
| /// made to the tree. In particular, this ordering is preserved across incremental compilations. |
| pub fn stable_cmp(&self, tcx: TyCtxt<'tcx>, other: &Self) -> Ordering { |
| use self::ExistentialPredicate::*; |
| match (*self, *other) { |
| (Trait(_), Trait(_)) => Ordering::Equal, |
| (Projection(ref a), Projection(ref b)) => { |
| tcx.def_path_hash(a.def_id).cmp(&tcx.def_path_hash(b.def_id)) |
| } |
| (AutoTrait(ref a), AutoTrait(ref b)) => { |
| tcx.def_path_hash(*a).cmp(&tcx.def_path_hash(*b)) |
| } |
| (Trait(_), _) => Ordering::Less, |
| (Projection(_), Trait(_)) => Ordering::Greater, |
| (Projection(_), _) => Ordering::Less, |
| (AutoTrait(_), _) => Ordering::Greater, |
| } |
| } |
| } |
| |
| pub type PolyExistentialPredicate<'tcx> = Binder<'tcx, ExistentialPredicate<'tcx>>; |
| |
| impl<'tcx> PolyExistentialPredicate<'tcx> { |
| /// Given an existential predicate like `?Self: PartialEq<u32>` (e.g., derived from `dyn PartialEq<u32>`), |
| /// and a concrete type `self_ty`, returns a full predicate where the existentially quantified variable `?Self` |
| /// has been replaced with `self_ty` (e.g., `self_ty: PartialEq<u32>`, in our example). |
| pub fn with_self_ty(&self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> ty::Predicate<'tcx> { |
| use crate::ty::ToPredicate; |
| match self.skip_binder() { |
| ExistentialPredicate::Trait(tr) => { |
| self.rebind(tr).with_self_ty(tcx, self_ty).without_const().to_predicate(tcx) |
| } |
| ExistentialPredicate::Projection(p) => { |
| self.rebind(p.with_self_ty(tcx, self_ty)).to_predicate(tcx) |
| } |
| ExistentialPredicate::AutoTrait(did) => { |
| let generics = tcx.generics_of(did); |
| let trait_ref = if generics.params.len() == 1 { |
| tcx.mk_trait_ref(did, [self_ty]) |
| } else { |
| // If this is an ill-formed auto trait, then synthesize |
| // new error substs for the missing generics. |
| let err_substs = |
| ty::InternalSubsts::extend_with_error(tcx, did, &[self_ty.into()]); |
| tcx.mk_trait_ref(did, err_substs) |
| }; |
| self.rebind(trait_ref).without_const().to_predicate(tcx) |
| } |
| } |
| } |
| } |
| |
| impl<'tcx> List<ty::PolyExistentialPredicate<'tcx>> { |
| /// Returns the "principal `DefId`" of this set of existential predicates. |
| /// |
| /// A Rust trait object type consists (in addition to a lifetime bound) |
| /// of a set of trait bounds, which are separated into any number |
| /// of auto-trait bounds, and at most one non-auto-trait bound. The |
| /// non-auto-trait bound is called the "principal" of the trait |
| /// object. |
| /// |
| /// Only the principal can have methods or type parameters (because |
| /// auto traits can have neither of them). This is important, because |
| /// it means the auto traits can be treated as an unordered set (methods |
| /// would force an order for the vtable, while relating traits with |
| /// type parameters without knowing the order to relate them in is |
| /// a rather non-trivial task). |
| /// |
| /// For example, in the trait object `dyn fmt::Debug + Sync`, the |
| /// principal bound is `Some(fmt::Debug)`, while the auto-trait bounds |
| /// are the set `{Sync}`. |
| /// |
| /// It is also possible to have a "trivial" trait object that |
| /// consists only of auto traits, with no principal - for example, |
| /// `dyn Send + Sync`. In that case, the set of auto-trait bounds |
| /// is `{Send, Sync}`, while there is no principal. These trait objects |
| /// have a "trivial" vtable consisting of just the size, alignment, |
| /// and destructor. |
| pub fn principal(&self) -> Option<ty::Binder<'tcx, ExistentialTraitRef<'tcx>>> { |
| self[0] |
| .map_bound(|this| match this { |
| ExistentialPredicate::Trait(tr) => Some(tr), |
| _ => None, |
| }) |
| .transpose() |
| } |
| |
| pub fn principal_def_id(&self) -> Option<DefId> { |
| self.principal().map(|trait_ref| trait_ref.skip_binder().def_id) |
| } |
| |
| #[inline] |
| pub fn projection_bounds<'a>( |
| &'a self, |
| ) -> impl Iterator<Item = ty::Binder<'tcx, ExistentialProjection<'tcx>>> + 'a { |
| self.iter().filter_map(|predicate| { |
| predicate |
| .map_bound(|pred| match pred { |
| ExistentialPredicate::Projection(projection) => Some(projection), |
| _ => None, |
| }) |
| .transpose() |
| }) |
| } |
| |
| #[inline] |
| pub fn auto_traits<'a>(&'a self) -> impl Iterator<Item = DefId> + Captures<'tcx> + 'a { |
| self.iter().filter_map(|predicate| match predicate.skip_binder() { |
| ExistentialPredicate::AutoTrait(did) => Some(did), |
| _ => None, |
| }) |
| } |
| } |
| |
| /// A complete reference to a trait. These take numerous guises in syntax, |
| /// but perhaps the most recognizable form is in a where-clause: |
| /// ```ignore (illustrative) |
| /// T: Foo<U> |
| /// ``` |
| /// This would be represented by a trait-reference where the `DefId` is the |
| /// `DefId` for the trait `Foo` and the substs define `T` as parameter 0, |
| /// and `U` as parameter 1. |
| /// |
| /// Trait references also appear in object types like `Foo<U>`, but in |
| /// that case the `Self` parameter is absent from the substitutions. |
| #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)] |
| #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)] |
| pub struct TraitRef<'tcx> { |
| pub def_id: DefId, |
| pub substs: SubstsRef<'tcx>, |
| /// This field exists to prevent the creation of `TraitRef` without |
| /// calling [TyCtxt::mk_trait_ref]. |
| pub(super) _use_mk_trait_ref_instead: (), |
| } |
| |
| impl<'tcx> TraitRef<'tcx> { |
| pub fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self { |
| tcx.mk_trait_ref( |
| self.def_id, |
| [self_ty.into()].into_iter().chain(self.substs.iter().skip(1)), |
| ) |
| } |
| |
| /// Returns a `TraitRef` of the form `P0: Foo<P1..Pn>` where `Pi` |
| /// are the parameters defined on trait. |
| pub fn identity(tcx: TyCtxt<'tcx>, def_id: DefId) -> Binder<'tcx, TraitRef<'tcx>> { |
| ty::Binder::dummy(tcx.mk_trait_ref(def_id, InternalSubsts::identity_for_item(tcx, def_id))) |
| } |
| |
| #[inline] |
| pub fn self_ty(&self) -> Ty<'tcx> { |
| self.substs.type_at(0) |
| } |
| |
| pub fn from_method( |
| tcx: TyCtxt<'tcx>, |
| trait_id: DefId, |
| substs: SubstsRef<'tcx>, |
| ) -> ty::TraitRef<'tcx> { |
| let defs = tcx.generics_of(trait_id); |
| tcx.mk_trait_ref(trait_id, tcx.mk_substs(&substs[..defs.params.len()])) |
| } |
| } |
| |
| pub type PolyTraitRef<'tcx> = Binder<'tcx, TraitRef<'tcx>>; |
| |
| impl<'tcx> PolyTraitRef<'tcx> { |
| pub fn self_ty(&self) -> Binder<'tcx, Ty<'tcx>> { |
| self.map_bound_ref(|tr| tr.self_ty()) |
| } |
| |
| pub fn def_id(&self) -> DefId { |
| self.skip_binder().def_id |
| } |
| } |
| |
| impl rustc_errors::IntoDiagnosticArg for PolyTraitRef<'_> { |
| fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> { |
| self.to_string().into_diagnostic_arg() |
| } |
| } |
| |
| /// An existential reference to a trait, where `Self` is erased. |
| /// For example, the trait object `Trait<'a, 'b, X, Y>` is: |
| /// ```ignore (illustrative) |
| /// exists T. T: Trait<'a, 'b, X, Y> |
| /// ``` |
| /// The substitutions don't include the erased `Self`, only trait |
| /// type and lifetime parameters (`[X, Y]` and `['a, 'b]` above). |
| #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)] |
| #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)] |
| pub struct ExistentialTraitRef<'tcx> { |
| pub def_id: DefId, |
| pub substs: SubstsRef<'tcx>, |
| } |
| |
| impl<'tcx> ExistentialTraitRef<'tcx> { |
| pub fn erase_self_ty( |
| tcx: TyCtxt<'tcx>, |
| trait_ref: ty::TraitRef<'tcx>, |
| ) -> ty::ExistentialTraitRef<'tcx> { |
| // Assert there is a Self. |
| trait_ref.substs.type_at(0); |
| |
| ty::ExistentialTraitRef { |
| def_id: trait_ref.def_id, |
| substs: tcx.mk_substs(&trait_ref.substs[1..]), |
| } |
| } |
| |
| /// Object types don't have a self type specified. Therefore, when |
| /// we convert the principal trait-ref into a normal trait-ref, |
| /// you must give *some* self type. A common choice is `mk_err()` |
| /// or some placeholder type. |
| pub fn with_self_ty(&self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> ty::TraitRef<'tcx> { |
| // otherwise the escaping vars would be captured by the binder |
| // debug_assert!(!self_ty.has_escaping_bound_vars()); |
| |
| tcx.mk_trait_ref(self.def_id, [self_ty.into()].into_iter().chain(self.substs.iter())) |
| } |
| } |
| |
| pub type PolyExistentialTraitRef<'tcx> = Binder<'tcx, ExistentialTraitRef<'tcx>>; |
| |
| impl<'tcx> PolyExistentialTraitRef<'tcx> { |
| pub fn def_id(&self) -> DefId { |
| self.skip_binder().def_id |
| } |
| |
| /// Object types don't have a self type specified. Therefore, when |
| /// we convert the principal trait-ref into a normal trait-ref, |
| /// you must give *some* self type. A common choice is `mk_err()` |
| /// or some placeholder type. |
| pub fn with_self_ty(&self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> ty::PolyTraitRef<'tcx> { |
| self.map_bound(|trait_ref| trait_ref.with_self_ty(tcx, self_ty)) |
| } |
| } |
| |
| impl rustc_errors::IntoDiagnosticArg for PolyExistentialTraitRef<'_> { |
| fn into_diagnostic_arg(self) -> rustc_errors::DiagnosticArgValue<'static> { |
| self.to_string().into_diagnostic_arg() |
| } |
| } |
| |
| #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] |
| #[derive(HashStable)] |
| pub enum BoundVariableKind { |
| Ty(BoundTyKind), |
| Region(BoundRegionKind), |
| Const, |
| } |
| |
| impl BoundVariableKind { |
| pub fn expect_region(self) -> BoundRegionKind { |
| match self { |
| BoundVariableKind::Region(lt) => lt, |
| _ => bug!("expected a region, but found another kind"), |
| } |
| } |
| |
| pub fn expect_ty(self) -> BoundTyKind { |
| match self { |
| BoundVariableKind::Ty(ty) => ty, |
| _ => bug!("expected a type, but found another kind"), |
| } |
| } |
| |
| pub fn expect_const(self) { |
| match self { |
| BoundVariableKind::Const => (), |
| _ => bug!("expected a const, but found another kind"), |
| } |
| } |
| } |
| |
| /// Binder is a binder for higher-ranked lifetimes or types. It is part of the |
| /// compiler's representation for things like `for<'a> Fn(&'a isize)` |
| /// (which would be represented by the type `PolyTraitRef == |
| /// Binder<'tcx, TraitRef>`). Note that when we instantiate, |
| /// erase, or otherwise "discharge" these bound vars, we change the |
| /// type from `Binder<'tcx, T>` to just `T` (see |
| /// e.g., `liberate_late_bound_regions`). |
| /// |
| /// `Decodable` and `Encodable` are implemented for `Binder<T>` using the `impl_binder_encode_decode!` macro. |
| #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)] |
| #[derive(HashStable, Lift)] |
| pub struct Binder<'tcx, T>(T, &'tcx List<BoundVariableKind>); |
| |
| impl<'tcx, T> Binder<'tcx, T> |
| where |
| T: TypeVisitable<TyCtxt<'tcx>>, |
| { |
| /// Wraps `value` in a binder, asserting that `value` does not |
| /// contain any bound vars that would be bound by the |
| /// binder. This is commonly used to 'inject' a value T into a |
| /// different binding level. |
| #[track_caller] |
| pub fn dummy(value: T) -> Binder<'tcx, T> { |
| assert!( |
| !value.has_escaping_bound_vars(), |
| "`{value:?}` has escaping bound vars, so it cannot be wrapped in a dummy binder." |
| ); |
| Binder(value, ty::List::empty()) |
| } |
| |
| pub fn bind_with_vars(value: T, vars: &'tcx List<BoundVariableKind>) -> Binder<'tcx, T> { |
| if cfg!(debug_assertions) { |
| let mut validator = ValidateBoundVars::new(vars); |
| value.visit_with(&mut validator); |
| } |
| Binder(value, vars) |
| } |
| } |
| |
| impl<'tcx, T> Binder<'tcx, T> { |
| /// Skips the binder and returns the "bound" value. This is a |
| /// risky thing to do because it's easy to get confused about |
| /// De Bruijn indices and the like. It is usually better to |
| /// discharge the binder using `no_bound_vars` or |
| /// `replace_late_bound_regions` or something like |
| /// that. `skip_binder` is only valid when you are either |
| /// extracting data that has nothing to do with bound vars, you |
| /// are doing some sort of test that does not involve bound |
| /// regions, or you are being very careful about your depth |
| /// accounting. |
| /// |
| /// Some examples where `skip_binder` is reasonable: |
| /// |
| /// - extracting the `DefId` from a PolyTraitRef; |
| /// - comparing the self type of a PolyTraitRef to see if it is equal to |
| /// a type parameter `X`, since the type `X` does not reference any regions |
| pub fn skip_binder(self) -> T { |
| self.0 |
| } |
| |
| pub fn bound_vars(&self) -> &'tcx List<BoundVariableKind> { |
| self.1 |
| } |
| |
| pub fn as_ref(&self) -> Binder<'tcx, &T> { |
| Binder(&self.0, self.1) |
| } |
| |
| pub fn as_deref(&self) -> Binder<'tcx, &T::Target> |
| where |
| T: Deref, |
| { |
| Binder(&self.0, self.1) |
| } |
| |
| pub fn map_bound_ref_unchecked<F, U>(&self, f: F) -> Binder<'tcx, U> |
| where |
| F: FnOnce(&T) -> U, |
| { |
| let value = f(&self.0); |
| Binder(value, self.1) |
| } |
| |
| pub fn map_bound_ref<F, U: TypeVisitable<TyCtxt<'tcx>>>(&self, f: F) -> Binder<'tcx, U> |
| where |
| F: FnOnce(&T) -> U, |
| { |
| self.as_ref().map_bound(f) |
| } |
| |
| pub fn map_bound<F, U: TypeVisitable<TyCtxt<'tcx>>>(self, f: F) -> Binder<'tcx, U> |
| where |
| F: FnOnce(T) -> U, |
| { |
| let value = f(self.0); |
| if cfg!(debug_assertions) { |
| let mut validator = ValidateBoundVars::new(self.1); |
| value.visit_with(&mut validator); |
| } |
| Binder(value, self.1) |
| } |
| |
| pub fn try_map_bound<F, U: TypeVisitable<TyCtxt<'tcx>>, E>( |
| self, |
| f: F, |
| ) -> Result<Binder<'tcx, U>, E> |
| where |
| F: FnOnce(T) -> Result<U, E>, |
| { |
| let value = f(self.0)?; |
| if cfg!(debug_assertions) { |
| let mut validator = ValidateBoundVars::new(self.1); |
| value.visit_with(&mut validator); |
| } |
| Ok(Binder(value, self.1)) |
| } |
| |
| /// Wraps a `value` in a binder, using the same bound variables as the |
| /// current `Binder`. This should not be used if the new value *changes* |
| /// the bound variables. Note: the (old or new) value itself does not |
| /// necessarily need to *name* all the bound variables. |
| /// |
| /// This currently doesn't do anything different than `bind`, because we |
| /// don't actually track bound vars. However, semantically, it is different |
| /// because bound vars aren't allowed to change here, whereas they are |
| /// in `bind`. This may be (debug) asserted in the future. |
| pub fn rebind<U>(&self, value: U) -> Binder<'tcx, U> |
| where |
| U: TypeVisitable<TyCtxt<'tcx>>, |
| { |
| if cfg!(debug_assertions) { |
| let mut validator = ValidateBoundVars::new(self.bound_vars()); |
| value.visit_with(&mut validator); |
| } |
| Binder(value, self.1) |
| } |
| |
| /// Unwraps and returns the value within, but only if it contains |
| /// no bound vars at all. (In other words, if this binder -- |
| /// and indeed any enclosing binder -- doesn't bind anything at |
| /// all.) Otherwise, returns `None`. |
| /// |
| /// (One could imagine having a method that just unwraps a single |
| /// binder, but permits late-bound vars bound by enclosing |
| /// binders, but that would require adjusting the debruijn |
| /// indices, and given the shallow binding structure we often use, |
| /// would not be that useful.) |
| pub fn no_bound_vars(self) -> Option<T> |
| where |
| T: TypeVisitable<TyCtxt<'tcx>>, |
| { |
| if self.0.has_escaping_bound_vars() { None } else { Some(self.skip_binder()) } |
| } |
| |
| /// Splits the contents into two things that share the same binder |
| /// level as the original, returning two distinct binders. |
| /// |
| /// `f` should consider bound regions at depth 1 to be free, and |
| /// anything it produces with bound regions at depth 1 will be |
| /// bound in the resulting return values. |
| pub fn split<U, V, F>(self, f: F) -> (Binder<'tcx, U>, Binder<'tcx, V>) |
| where |
| F: FnOnce(T) -> (U, V), |
| { |
| let (u, v) = f(self.0); |
| (Binder(u, self.1), Binder(v, self.1)) |
| } |
| } |
| |
| impl<'tcx, T> Binder<'tcx, Option<T>> { |
| pub fn transpose(self) -> Option<Binder<'tcx, T>> { |
| let bound_vars = self.1; |
| self.0.map(|v| Binder(v, bound_vars)) |
| } |
| } |
| |
| impl<'tcx, T: IntoIterator> Binder<'tcx, T> { |
| pub fn iter(self) -> impl Iterator<Item = ty::Binder<'tcx, T::Item>> { |
| let bound_vars = self.1; |
| self.0.into_iter().map(|v| Binder(v, bound_vars)) |
| } |
| } |
| |
| struct SkipBindersAt<'tcx> { |
| tcx: TyCtxt<'tcx>, |
| index: ty::DebruijnIndex, |
| } |
| |
| impl<'tcx> FallibleTypeFolder<TyCtxt<'tcx>> for SkipBindersAt<'tcx> { |
| type Error = (); |
| |
| fn interner(&self) -> TyCtxt<'tcx> { |
| self.tcx |
| } |
| |
| fn try_fold_binder<T>(&mut self, t: Binder<'tcx, T>) -> Result<Binder<'tcx, T>, Self::Error> |
| where |
| T: ty::TypeFoldable<TyCtxt<'tcx>>, |
| { |
| self.index.shift_in(1); |
| let value = t.try_map_bound(|t| t.try_fold_with(self)); |
| self.index.shift_out(1); |
| value |
| } |
| |
| fn try_fold_ty(&mut self, ty: Ty<'tcx>) -> Result<Ty<'tcx>, Self::Error> { |
| if !ty.has_escaping_bound_vars() { |
| Ok(ty) |
| } else if let ty::Bound(index, bv) = *ty.kind() { |
| if index == self.index { |
| Err(()) |
| } else { |
| Ok(self.interner().mk_bound(index.shifted_out(1), bv)) |
| } |
| } else { |
| ty.try_super_fold_with(self) |
| } |
| } |
| |
| fn try_fold_region(&mut self, r: ty::Region<'tcx>) -> Result<ty::Region<'tcx>, Self::Error> { |
| if !r.has_escaping_bound_vars() { |
| Ok(r) |
| } else if let ty::ReLateBound(index, bv) = r.kind() { |
| if index == self.index { |
| Err(()) |
| } else { |
| Ok(self.interner().mk_re_late_bound(index.shifted_out(1), bv)) |
| } |
| } else { |
| r.try_super_fold_with(self) |
| } |
| } |
| |
| fn try_fold_const(&mut self, ct: ty::Const<'tcx>) -> Result<ty::Const<'tcx>, Self::Error> { |
| if !ct.has_escaping_bound_vars() { |
| Ok(ct) |
| } else if let ty::ConstKind::Bound(index, bv) = ct.kind() { |
| if index == self.index { |
| Err(()) |
| } else { |
| Ok(self.interner().mk_const( |
| ty::ConstKind::Bound(index.shifted_out(1), bv), |
| ct.ty().try_fold_with(self)?, |
| )) |
| } |
| } else { |
| ct.try_super_fold_with(self) |
| } |
| } |
| |
| fn try_fold_predicate( |
| &mut self, |
| p: ty::Predicate<'tcx>, |
| ) -> Result<ty::Predicate<'tcx>, Self::Error> { |
| if !p.has_escaping_bound_vars() { Ok(p) } else { p.try_super_fold_with(self) } |
| } |
| } |
| |
| /// Represents the projection of an associated type. |
| /// |
| /// For a projection, this would be `<Ty as Trait<...>>::N`. |
| /// |
| /// For an opaque type, there is no explicit syntax. |
| #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)] |
| #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)] |
| pub struct AliasTy<'tcx> { |
| /// The parameters of the associated or opaque item. |
| /// |
| /// For a projection, these are the substitutions for the trait and the |
| /// GAT substitutions, if there are any. |
| /// |
| /// For RPIT the substitutions are for the generics of the function, |
| /// while for TAIT it is used for the generic parameters of the alias. |
| pub substs: SubstsRef<'tcx>, |
| |
| /// The `DefId` of the `TraitItem` for the associated type `N` if this is a projection, |
| /// or the `OpaqueType` item if this is an opaque. |
| /// |
| /// During codegen, `tcx.type_of(def_id)` can be used to get the type of the |
| /// underlying type if the type is an opaque. |
| /// |
| /// Note that if this is an associated type, this is not the `DefId` of the |
| /// `TraitRef` containing this associated type, which is in `tcx.associated_item(def_id).container`, |
| /// aka. `tcx.parent(def_id)`. |
| pub def_id: DefId, |
| |
| /// This field exists to prevent the creation of `AliasTy` without using |
| /// [TyCtxt::mk_alias_ty]. |
| pub(super) _use_mk_alias_ty_instead: (), |
| } |
| |
| impl<'tcx> AliasTy<'tcx> { |
| pub fn kind(self, tcx: TyCtxt<'tcx>) -> ty::AliasKind { |
| match tcx.def_kind(self.def_id) { |
| DefKind::AssocTy | DefKind::ImplTraitPlaceholder => ty::Projection, |
| DefKind::OpaqueTy => ty::Opaque, |
| kind => bug!("unexpected DefKind in AliasTy: {kind:?}"), |
| } |
| } |
| |
| pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
| tcx.mk_alias(self.kind(tcx), self) |
| } |
| } |
| |
| /// The following methods work only with associated type projections. |
| impl<'tcx> AliasTy<'tcx> { |
| pub fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId { |
| match tcx.def_kind(self.def_id) { |
| DefKind::AssocTy | DefKind::AssocConst => tcx.parent(self.def_id), |
| DefKind::ImplTraitPlaceholder => { |
| tcx.parent(tcx.impl_trait_in_trait_parent(self.def_id)) |
| } |
| kind => bug!("expected a projection AliasTy; found {kind:?}"), |
| } |
| } |
| |
| /// Extracts the underlying trait reference and own substs from this projection. |
| /// For example, if this is a projection of `<T as StreamingIterator>::Item<'a>`, |
| /// then this function would return a `T: Iterator` trait reference and `['a]` as the own substs |
| pub fn trait_ref_and_own_substs( |
| self, |
| tcx: TyCtxt<'tcx>, |
| ) -> (ty::TraitRef<'tcx>, &'tcx [ty::GenericArg<'tcx>]) { |
| debug_assert!(matches!(tcx.def_kind(self.def_id), DefKind::AssocTy | DefKind::AssocConst)); |
| let trait_def_id = self.trait_def_id(tcx); |
| let trait_generics = tcx.generics_of(trait_def_id); |
| ( |
| tcx.mk_trait_ref(trait_def_id, self.substs.truncate_to(tcx, trait_generics)), |
| &self.substs[trait_generics.count()..], |
| ) |
| } |
| |
| /// Extracts the underlying trait reference from this projection. |
| /// For example, if this is a projection of `<T as Iterator>::Item`, |
| /// then this function would return a `T: Iterator` trait reference. |
| /// |
| /// WARNING: This will drop the substs for generic associated types |
| /// consider calling [Self::trait_ref_and_own_substs] to get those |
| /// as well. |
| pub fn trait_ref(self, tcx: TyCtxt<'tcx>) -> ty::TraitRef<'tcx> { |
| let def_id = self.trait_def_id(tcx); |
| tcx.mk_trait_ref(def_id, self.substs.truncate_to(tcx, tcx.generics_of(def_id))) |
| } |
| |
| pub fn self_ty(self) -> Ty<'tcx> { |
| self.substs.type_at(0) |
| } |
| |
| pub fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self { |
| tcx.mk_alias_ty(self.def_id, [self_ty.into()].into_iter().chain(self.substs.iter().skip(1))) |
| } |
| } |
| |
| #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, Lift)] |
| pub struct GenSig<'tcx> { |
| pub resume_ty: Ty<'tcx>, |
| pub yield_ty: Ty<'tcx>, |
| pub return_ty: Ty<'tcx>, |
| } |
| |
| pub type PolyGenSig<'tcx> = Binder<'tcx, GenSig<'tcx>>; |
| |
| /// Signature of a function type, which we have arbitrarily |
| /// decided to use to refer to the input/output types. |
| /// |
| /// - `inputs`: is the list of arguments and their modes. |
| /// - `output`: is the return type. |
| /// - `c_variadic`: indicates whether this is a C-variadic function. |
| #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)] |
| #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)] |
| pub struct FnSig<'tcx> { |
| pub inputs_and_output: &'tcx List<Ty<'tcx>>, |
| pub c_variadic: bool, |
| pub unsafety: hir::Unsafety, |
| pub abi: abi::Abi, |
| } |
| |
| impl<'tcx> FnSig<'tcx> { |
| pub fn inputs(&self) -> &'tcx [Ty<'tcx>] { |
| &self.inputs_and_output[..self.inputs_and_output.len() - 1] |
| } |
| |
| pub fn output(&self) -> Ty<'tcx> { |
| self.inputs_and_output[self.inputs_and_output.len() - 1] |
| } |
| |
| // Creates a minimal `FnSig` to be used when encountering a `TyKind::Error` in a fallible |
| // method. |
| fn fake() -> FnSig<'tcx> { |
| FnSig { |
| inputs_and_output: List::empty(), |
| c_variadic: false, |
| unsafety: hir::Unsafety::Normal, |
| abi: abi::Abi::Rust, |
| } |
| } |
| } |
| |
| pub type PolyFnSig<'tcx> = Binder<'tcx, FnSig<'tcx>>; |
| |
| impl<'tcx> PolyFnSig<'tcx> { |
| #[inline] |
| pub fn inputs(&self) -> Binder<'tcx, &'tcx [Ty<'tcx>]> { |
| self.map_bound_ref_unchecked(|fn_sig| fn_sig.inputs()) |
| } |
| #[inline] |
| pub fn input(&self, index: usize) -> ty::Binder<'tcx, Ty<'tcx>> { |
| self.map_bound_ref(|fn_sig| fn_sig.inputs()[index]) |
| } |
| pub fn inputs_and_output(&self) -> ty::Binder<'tcx, &'tcx List<Ty<'tcx>>> { |
| self.map_bound_ref(|fn_sig| fn_sig.inputs_and_output) |
| } |
| #[inline] |
| pub fn output(&self) -> ty::Binder<'tcx, Ty<'tcx>> { |
| self.map_bound_ref(|fn_sig| fn_sig.output()) |
| } |
| pub fn c_variadic(&self) -> bool { |
| self.skip_binder().c_variadic |
| } |
| pub fn unsafety(&self) -> hir::Unsafety { |
| self.skip_binder().unsafety |
| } |
| pub fn abi(&self) -> abi::Abi { |
| self.skip_binder().abi |
| } |
| } |
| |
| pub type CanonicalPolyFnSig<'tcx> = Canonical<'tcx, Binder<'tcx, FnSig<'tcx>>>; |
| |
| #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)] |
| #[derive(HashStable)] |
| pub struct ParamTy { |
| pub index: u32, |
| pub name: Symbol, |
| } |
| |
| impl<'tcx> ParamTy { |
| pub fn new(index: u32, name: Symbol) -> ParamTy { |
| ParamTy { index, name } |
| } |
| |
| pub fn for_def(def: &ty::GenericParamDef) -> ParamTy { |
| ParamTy::new(def.index, def.name) |
| } |
| |
| #[inline] |
| pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
| tcx.mk_ty_param(self.index, self.name) |
| } |
| |
| pub fn span_from_generics(&self, tcx: TyCtxt<'tcx>, item_with_generics: DefId) -> Span { |
| let generics = tcx.generics_of(item_with_generics); |
| let type_param = generics.type_param(self, tcx); |
| tcx.def_span(type_param.def_id) |
| } |
| } |
| |
| #[derive(Copy, Clone, Hash, TyEncodable, TyDecodable, Eq, PartialEq, Ord, PartialOrd)] |
| #[derive(HashStable)] |
| pub struct ParamConst { |
| pub index: u32, |
| pub name: Symbol, |
| } |
| |
| impl ParamConst { |
| pub fn new(index: u32, name: Symbol) -> ParamConst { |
| ParamConst { index, name } |
| } |
| |
| pub fn for_def(def: &ty::GenericParamDef) -> ParamConst { |
| ParamConst::new(def.index, def.name) |
| } |
| } |
| |
| /// Use this rather than `RegionKind`, whenever possible. |
| #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, HashStable)] |
| #[rustc_pass_by_value] |
| pub struct Region<'tcx>(pub Interned<'tcx, RegionKind<'tcx>>); |
| |
| impl<'tcx> Deref for Region<'tcx> { |
| type Target = RegionKind<'tcx>; |
| |
| #[inline] |
| fn deref(&self) -> &RegionKind<'tcx> { |
| &self.0.0 |
| } |
| } |
| |
| impl<'tcx> fmt::Debug for Region<'tcx> { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| write!(f, "{:?}", self.kind()) |
| } |
| } |
| |
| #[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, PartialOrd, Ord)] |
| #[derive(HashStable)] |
| pub struct EarlyBoundRegion { |
| pub def_id: DefId, |
| pub index: u32, |
| pub name: Symbol, |
| } |
| |
| impl fmt::Debug for EarlyBoundRegion { |
| fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| write!(f, "{}, {}", self.index, self.name) |
| } |
| } |
| |
| /// A **`const`** **v**ariable **ID**. |
| #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)] |
| #[derive(HashStable, TyEncodable, TyDecodable)] |
| pub struct ConstVid<'tcx> { |
| pub index: u32, |
| pub phantom: PhantomData<&'tcx ()>, |
| } |
| |
| rustc_index::newtype_index! { |
| /// A **region** (lifetime) **v**ariable **ID**. |
| #[derive(HashStable)] |
| #[debug_format = "'_#{}r"] |
| pub struct RegionVid {} |
| } |
| |
| impl Atom for RegionVid { |
| fn index(self) -> usize { |
| Idx::index(self) |
| } |
| } |
| |
| rustc_index::newtype_index! { |
| #[derive(HashStable)] |
| pub struct BoundVar {} |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] |
| #[derive(HashStable)] |
| pub struct BoundTy { |
| pub var: BoundVar, |
| pub kind: BoundTyKind, |
| } |
| |
| #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] |
| #[derive(HashStable)] |
| pub enum BoundTyKind { |
| Anon(u32), |
| Param(DefId, Symbol), |
| } |
| |
| impl BoundTyKind { |
| pub fn expect_anon(self) -> u32 { |
| match self { |
| BoundTyKind::Anon(i) => i, |
| _ => bug!(), |
| } |
| } |
| } |
| |
| impl From<BoundVar> for BoundTy { |
| fn from(var: BoundVar) -> Self { |
| BoundTy { var, kind: BoundTyKind::Anon(var.as_u32()) } |
| } |
| } |
| |
| /// A `ProjectionPredicate` for an `ExistentialTraitRef`. |
| #[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)] |
| #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)] |
| pub struct ExistentialProjection<'tcx> { |
| pub def_id: DefId, |
| pub substs: SubstsRef<'tcx>, |
| pub term: Term<'tcx>, |
| } |
| |
| pub type PolyExistentialProjection<'tcx> = Binder<'tcx, ExistentialProjection<'tcx>>; |
| |
| impl<'tcx> ExistentialProjection<'tcx> { |
| /// Extracts the underlying existential trait reference from this projection. |
| /// For example, if this is a projection of `exists T. <T as Iterator>::Item == X`, |
| /// then this function would return an `exists T. T: Iterator` existential trait |
| /// reference. |
| pub fn trait_ref(&self, tcx: TyCtxt<'tcx>) -> ty::ExistentialTraitRef<'tcx> { |
| let def_id = tcx.parent(self.def_id); |
| let subst_count = tcx.generics_of(def_id).count() - 1; |
| let substs = tcx.mk_substs(&self.substs[..subst_count]); |
| ty::ExistentialTraitRef { def_id, substs } |
| } |
| |
| pub fn with_self_ty( |
| &self, |
| tcx: TyCtxt<'tcx>, |
| self_ty: Ty<'tcx>, |
| ) -> ty::ProjectionPredicate<'tcx> { |
| // otherwise the escaping regions would be captured by the binders |
| debug_assert!(!self_ty.has_escaping_bound_vars()); |
| |
| ty::ProjectionPredicate { |
| projection_ty: tcx |
| .mk_alias_ty(self.def_id, [self_ty.into()].into_iter().chain(self.substs)), |
| term: self.term, |
| } |
| } |
| |
| pub fn erase_self_ty( |
| tcx: TyCtxt<'tcx>, |
| projection_predicate: ty::ProjectionPredicate<'tcx>, |
| ) -> Self { |
| // Assert there is a Self. |
| projection_predicate.projection_ty.substs.type_at(0); |
| |
| Self { |
| def_id: projection_predicate.projection_ty.def_id, |
| substs: tcx.mk_substs(&projection_predicate.projection_ty.substs[1..]), |
| term: projection_predicate.term, |
| } |
| } |
| } |
| |
| impl<'tcx> PolyExistentialProjection<'tcx> { |
| pub fn with_self_ty( |
| &self, |
| tcx: TyCtxt<'tcx>, |
| self_ty: Ty<'tcx>, |
| ) -> ty::PolyProjectionPredicate<'tcx> { |
| self.map_bound(|p| p.with_self_ty(tcx, self_ty)) |
| } |
| |
| pub fn item_def_id(&self) -> DefId { |
| self.skip_binder().def_id |
| } |
| } |
| |
| /// Region utilities |
| impl<'tcx> Region<'tcx> { |
| pub fn kind(self) -> RegionKind<'tcx> { |
| *self.0.0 |
| } |
| |
| pub fn get_name(self) -> Option<Symbol> { |
| if self.has_name() { |
| let name = match *self { |
| ty::ReEarlyBound(ebr) => Some(ebr.name), |
| ty::ReLateBound(_, br) => br.kind.get_name(), |
| ty::ReFree(fr) => fr.bound_region.get_name(), |
| ty::ReStatic => Some(kw::StaticLifetime), |
| ty::RePlaceholder(placeholder) => placeholder.name.get_name(), |
| _ => None, |
| }; |
| |
| return name; |
| } |
| |
| None |
| } |
| |
| /// Is this region named by the user? |
| pub fn has_name(self) -> bool { |
| match *self { |
| ty::ReEarlyBound(ebr) => ebr.has_name(), |
| ty::ReLateBound(_, br) => br.kind.is_named(), |
| ty::ReFree(fr) => fr.bound_region.is_named(), |
| ty::ReStatic => true, |
| ty::ReVar(..) => false, |
| ty::RePlaceholder(placeholder) => placeholder.name.is_named(), |
| ty::ReErased => false, |
| ty::ReError(_) => false, |
| } |
| } |
| |
| #[inline] |
| pub fn is_error(self) -> bool { |
| matches!(*self, ty::ReError(_)) |
| } |
| |
| #[inline] |
| pub fn is_static(self) -> bool { |
| matches!(*self, ty::ReStatic) |
| } |
| |
| #[inline] |
| pub fn is_erased(self) -> bool { |
| matches!(*self, ty::ReErased) |
| } |
| |
| #[inline] |
| pub fn is_late_bound(self) -> bool { |
| matches!(*self, ty::ReLateBound(..)) |
| } |
| |
| #[inline] |
| pub fn is_placeholder(self) -> bool { |
| matches!(*self, ty::RePlaceholder(..)) |
| } |
| |
| #[inline] |
| pub fn bound_at_or_above_binder(self, index: ty::DebruijnIndex) -> bool { |
| match *self { |
| ty::ReLateBound(debruijn, _) => debruijn >= index, |
| _ => false, |
| } |
| } |
| |
| pub fn type_flags(self) -> TypeFlags { |
| let mut flags = TypeFlags::empty(); |
| |
| match *self { |
| ty::ReVar(..) => { |
| flags = flags | TypeFlags::HAS_FREE_REGIONS; |
| flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS; |
| flags = flags | TypeFlags::HAS_RE_INFER; |
| } |
| ty::RePlaceholder(..) => { |
| flags = flags | TypeFlags::HAS_FREE_REGIONS; |
| flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS; |
| flags = flags | TypeFlags::HAS_RE_PLACEHOLDER; |
| } |
| ty::ReEarlyBound(..) => { |
| flags = flags | TypeFlags::HAS_FREE_REGIONS; |
| flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS; |
| flags = flags | TypeFlags::HAS_RE_PARAM; |
| } |
| ty::ReFree { .. } => { |
| flags = flags | TypeFlags::HAS_FREE_REGIONS; |
| flags = flags | TypeFlags::HAS_FREE_LOCAL_REGIONS; |
| } |
| ty::ReStatic => { |
| flags = flags | TypeFlags::HAS_FREE_REGIONS; |
| } |
| ty::ReLateBound(..) => { |
| flags = flags | TypeFlags::HAS_RE_LATE_BOUND; |
| } |
| ty::ReErased => { |
| flags = flags | TypeFlags::HAS_RE_ERASED; |
| } |
| ty::ReError(_) => {} |
| } |
| |
| debug!("type_flags({:?}) = {:?}", self, flags); |
| |
| flags |
| } |
| |
| /// Given an early-bound or free region, returns the `DefId` where it was bound. |
| /// For example, consider the regions in this snippet of code: |
| /// |
| /// ```ignore (illustrative) |
| /// impl<'a> Foo { |
| /// // ^^ -- early bound, declared on an impl |
| /// |
| /// fn bar<'b, 'c>(x: &self, y: &'b u32, z: &'c u64) where 'static: 'c |
| /// // ^^ ^^ ^ anonymous, late-bound |
| /// // | early-bound, appears in where-clauses |
| /// // late-bound, appears only in fn args |
| /// {..} |
| /// } |
| /// ``` |
| /// |
| /// Here, `free_region_binding_scope('a)` would return the `DefId` |
| /// of the impl, and for all the other highlighted regions, it |
| /// would return the `DefId` of the function. In other cases (not shown), this |
| /// function might return the `DefId` of a closure. |
| pub fn free_region_binding_scope(self, tcx: TyCtxt<'_>) -> DefId { |
| match *self { |
| ty::ReEarlyBound(br) => tcx.parent(br.def_id), |
| ty::ReFree(fr) => fr.scope, |
| _ => bug!("free_region_binding_scope invoked on inappropriate region: {:?}", self), |
| } |
| } |
| |
| /// True for free regions other than `'static`. |
| pub fn is_free(self) -> bool { |
| matches!(*self, ty::ReEarlyBound(_) | ty::ReFree(_)) |
| } |
| |
| /// True if `self` is a free region or static. |
| pub fn is_free_or_static(self) -> bool { |
| match *self { |
| ty::ReStatic => true, |
| _ => self.is_free(), |
| } |
| } |
| |
| pub fn is_var(self) -> bool { |
| matches!(self.kind(), ty::ReVar(_)) |
| } |
| |
| pub fn as_var(self) -> Option<RegionVid> { |
| match self.kind() { |
| ty::ReVar(vid) => Some(vid), |
| _ => None, |
| } |
| } |
| } |
| |
| /// Type utilities |
| impl<'tcx> Ty<'tcx> { |
| #[inline(always)] |
| pub fn kind(self) -> &'tcx TyKind<'tcx> { |
| &self.0.0 |
| } |
| |
| #[inline(always)] |
| pub fn flags(self) -> TypeFlags { |
| self.0.0.flags |
| } |
| |
| #[inline] |
| pub fn is_unit(self) -> bool { |
| match self.kind() { |
| Tuple(ref tys) => tys.is_empty(), |
| _ => false, |
| } |
| } |
| |
| #[inline] |
| pub fn is_never(self) -> bool { |
| matches!(self.kind(), Never) |
| } |
| |
| #[inline] |
| pub fn is_primitive(self) -> bool { |
| self.kind().is_primitive() |
| } |
| |
| #[inline] |
| pub fn is_adt(self) -> bool { |
| matches!(self.kind(), Adt(..)) |
| } |
| |
| #[inline] |
| pub fn is_ref(self) -> bool { |
| matches!(self.kind(), Ref(..)) |
| } |
| |
| #[inline] |
| pub fn is_ty_var(self) -> bool { |
| matches!(self.kind(), Infer(TyVar(_))) |
| } |
| |
| #[inline] |
| pub fn ty_vid(self) -> Option<ty::TyVid> { |
| match self.kind() { |
| &Infer(TyVar(vid)) => Some(vid), |
| _ => None, |
| } |
| } |
| |
| #[inline] |
| pub fn is_ty_or_numeric_infer(self) -> bool { |
| matches!(self.kind(), Infer(_)) |
| } |
| |
| #[inline] |
| pub fn is_phantom_data(self) -> bool { |
| if let Adt(def, _) = self.kind() { def.is_phantom_data() } else { false } |
| } |
| |
| #[inline] |
| pub fn is_bool(self) -> bool { |
| *self.kind() == Bool |
| } |
| |
| /// Returns `true` if this type is a `str`. |
| #[inline] |
| pub fn is_str(self) -> bool { |
| *self.kind() == Str |
| } |
| |
| #[inline] |
| pub fn is_param(self, index: u32) -> bool { |
| match self.kind() { |
| ty::Param(ref data) => data.index == index, |
| _ => false, |
| } |
| } |
| |
| #[inline] |
| pub fn is_slice(self) -> bool { |
| matches!(self.kind(), Slice(_)) |
| } |
| |
| #[inline] |
| pub fn is_array_slice(self) -> bool { |
| match self.kind() { |
| Slice(_) => true, |
| RawPtr(TypeAndMut { ty, .. }) | Ref(_, ty, _) => matches!(ty.kind(), Slice(_)), |
| _ => false, |
| } |
| } |
| |
| #[inline] |
| pub fn is_array(self) -> bool { |
| matches!(self.kind(), Array(..)) |
| } |
| |
| #[inline] |
| pub fn is_simd(self) -> bool { |
| match self.kind() { |
| Adt(def, _) => def.repr().simd(), |
| _ => false, |
| } |
| } |
| |
| pub fn sequence_element_type(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
| match self.kind() { |
| Array(ty, _) | Slice(ty) => *ty, |
| Str => tcx.types.u8, |
| _ => bug!("`sequence_element_type` called on non-sequence value: {}", self), |
| } |
| } |
| |
| pub fn simd_size_and_type(self, tcx: TyCtxt<'tcx>) -> (u64, Ty<'tcx>) { |
| match self.kind() { |
| Adt(def, substs) => { |
| assert!(def.repr().simd(), "`simd_size_and_type` called on non-SIMD type"); |
| let variant = def.non_enum_variant(); |
| let f0_ty = variant.fields[0].ty(tcx, substs); |
| |
| match f0_ty.kind() { |
| // If the first field is an array, we assume it is the only field and its |
| // elements are the SIMD components. |
| Array(f0_elem_ty, f0_len) => { |
| // FIXME(repr_simd): https://github.com/rust-lang/rust/pull/78863#discussion_r522784112 |
| // The way we evaluate the `N` in `[T; N]` here only works since we use |
| // `simd_size_and_type` post-monomorphization. It will probably start to ICE |
| // if we use it in generic code. See the `simd-array-trait` ui test. |
| (f0_len.eval_target_usize(tcx, ParamEnv::empty()) as u64, *f0_elem_ty) |
| } |
| // Otherwise, the fields of this Adt are the SIMD components (and we assume they |
| // all have the same type). |
| _ => (variant.fields.len() as u64, f0_ty), |
| } |
| } |
| _ => bug!("`simd_size_and_type` called on invalid type"), |
| } |
| } |
| |
| #[inline] |
| pub fn is_region_ptr(self) -> bool { |
| matches!(self.kind(), Ref(..)) |
| } |
| |
| #[inline] |
| pub fn is_mutable_ptr(self) -> bool { |
| matches!( |
| self.kind(), |
| RawPtr(TypeAndMut { mutbl: hir::Mutability::Mut, .. }) |
| | Ref(_, _, hir::Mutability::Mut) |
| ) |
| } |
| |
| /// Get the mutability of the reference or `None` when not a reference |
| #[inline] |
| pub fn ref_mutability(self) -> Option<hir::Mutability> { |
| match self.kind() { |
| Ref(_, _, mutability) => Some(*mutability), |
| _ => None, |
| } |
| } |
| |
| #[inline] |
| pub fn is_unsafe_ptr(self) -> bool { |
| matches!(self.kind(), RawPtr(_)) |
| } |
| |
| /// Tests if this is any kind of primitive pointer type (reference, raw pointer, fn pointer). |
| #[inline] |
| pub fn is_any_ptr(self) -> bool { |
| self.is_region_ptr() || self.is_unsafe_ptr() || self.is_fn_ptr() |
| } |
| |
| #[inline] |
| pub fn is_box(self) -> bool { |
| match self.kind() { |
| Adt(def, _) => def.is_box(), |
| _ => false, |
| } |
| } |
| |
| /// Panics if called on any type other than `Box<T>`. |
| pub fn boxed_ty(self) -> Ty<'tcx> { |
| match self.kind() { |
| Adt(def, substs) if def.is_box() => substs.type_at(0), |
| _ => bug!("`boxed_ty` is called on non-box type {:?}", self), |
| } |
| } |
| |
| /// A scalar type is one that denotes an atomic datum, with no sub-components. |
| /// (A RawPtr is scalar because it represents a non-managed pointer, so its |
| /// contents are abstract to rustc.) |
| #[inline] |
| pub fn is_scalar(self) -> bool { |
| matches!( |
| self.kind(), |
| Bool | Char |
| | Int(_) |
| | Float(_) |
| | Uint(_) |
| | FnDef(..) |
| | FnPtr(_) |
| | RawPtr(_) |
| | Infer(IntVar(_) | FloatVar(_)) |
| ) |
| } |
| |
| /// Returns `true` if this type is a floating point type. |
| #[inline] |
| pub fn is_floating_point(self) -> bool { |
| matches!(self.kind(), Float(_) | Infer(FloatVar(_))) |
| } |
| |
| #[inline] |
| pub fn is_trait(self) -> bool { |
| matches!(self.kind(), Dynamic(_, _, ty::Dyn)) |
| } |
| |
| #[inline] |
| pub fn is_dyn_star(self) -> bool { |
| matches!(self.kind(), Dynamic(_, _, ty::DynStar)) |
| } |
| |
| #[inline] |
| pub fn is_enum(self) -> bool { |
| matches!(self.kind(), Adt(adt_def, _) if adt_def.is_enum()) |
| } |
| |
| #[inline] |
| pub fn is_union(self) -> bool { |
| matches!(self.kind(), Adt(adt_def, _) if adt_def.is_union()) |
| } |
| |
| #[inline] |
| pub fn is_closure(self) -> bool { |
| matches!(self.kind(), Closure(..)) |
| } |
| |
| #[inline] |
| pub fn is_generator(self) -> bool { |
| matches!(self.kind(), Generator(..)) |
| } |
| |
| #[inline] |
| pub fn is_integral(self) -> bool { |
| matches!(self.kind(), Infer(IntVar(_)) | Int(_) | Uint(_)) |
| } |
| |
| #[inline] |
| pub fn is_fresh_ty(self) -> bool { |
| matches!(self.kind(), Infer(FreshTy(_))) |
| } |
| |
| #[inline] |
| pub fn is_fresh(self) -> bool { |
| matches!(self.kind(), Infer(FreshTy(_) | FreshIntTy(_) | FreshFloatTy(_))) |
| } |
| |
| #[inline] |
| pub fn is_char(self) -> bool { |
| matches!(self.kind(), Char) |
| } |
| |
| #[inline] |
| pub fn is_numeric(self) -> bool { |
| self.is_integral() || self.is_floating_point() |
| } |
| |
| #[inline] |
| pub fn is_signed(self) -> bool { |
| matches!(self.kind(), Int(_)) |
| } |
| |
| #[inline] |
| pub fn is_ptr_sized_integral(self) -> bool { |
| matches!(self.kind(), Int(ty::IntTy::Isize) | Uint(ty::UintTy::Usize)) |
| } |
| |
| #[inline] |
| pub fn has_concrete_skeleton(self) -> bool { |
| !matches!(self.kind(), Param(_) | Infer(_) | Error(_)) |
| } |
| |
| /// Checks whether a type recursively contains another type |
| /// |
| /// Example: `Option<()>` contains `()` |
| pub fn contains(self, other: Ty<'tcx>) -> bool { |
| struct ContainsTyVisitor<'tcx>(Ty<'tcx>); |
| |
| impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ContainsTyVisitor<'tcx> { |
| type BreakTy = (); |
| |
| fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> { |
| if self.0 == t { ControlFlow::Break(()) } else { t.super_visit_with(self) } |
| } |
| } |
| |
| let cf = self.visit_with(&mut ContainsTyVisitor(other)); |
| cf.is_break() |
| } |
| |
| /// Checks whether a type recursively contains any closure |
| /// |
| /// Example: `Option<[closure@file.rs:4:20]>` returns true |
| pub fn contains_closure(self) -> bool { |
| struct ContainsClosureVisitor; |
| |
| impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ContainsClosureVisitor { |
| type BreakTy = (); |
| |
| fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> { |
| if let ty::Closure(_, _) = t.kind() { |
| ControlFlow::Break(()) |
| } else { |
| t.super_visit_with(self) |
| } |
| } |
| } |
| |
| let cf = self.visit_with(&mut ContainsClosureVisitor); |
| cf.is_break() |
| } |
| |
| /// Returns the type and mutability of `*ty`. |
| /// |
| /// The parameter `explicit` indicates if this is an *explicit* dereference. |
| /// Some types -- notably unsafe ptrs -- can only be dereferenced explicitly. |
| pub fn builtin_deref(self, explicit: bool) -> Option<TypeAndMut<'tcx>> { |
| match self.kind() { |
| Adt(def, _) if def.is_box() => { |
| Some(TypeAndMut { ty: self.boxed_ty(), mutbl: hir::Mutability::Not }) |
| } |
| Ref(_, ty, mutbl) => Some(TypeAndMut { ty: *ty, mutbl: *mutbl }), |
| RawPtr(mt) if explicit => Some(*mt), |
| _ => None, |
| } |
| } |
| |
| /// Returns the type of `ty[i]`. |
| pub fn builtin_index(self) -> Option<Ty<'tcx>> { |
| match self.kind() { |
| Array(ty, _) | Slice(ty) => Some(*ty), |
| _ => None, |
| } |
| } |
| |
| pub fn fn_sig(self, tcx: TyCtxt<'tcx>) -> PolyFnSig<'tcx> { |
| match self.kind() { |
| FnDef(def_id, substs) => tcx.fn_sig(*def_id).subst(tcx, substs), |
| FnPtr(f) => *f, |
| Error(_) => { |
| // ignore errors (#54954) |
| ty::Binder::dummy(FnSig::fake()) |
| } |
| Closure(..) => bug!( |
| "to get the signature of a closure, use `substs.as_closure().sig()` not `fn_sig()`", |
| ), |
| _ => bug!("Ty::fn_sig() called on non-fn type: {:?}", self), |
| } |
| } |
| |
| #[inline] |
| pub fn is_fn(self) -> bool { |
| matches!(self.kind(), FnDef(..) | FnPtr(_)) |
| } |
| |
| #[inline] |
| pub fn is_fn_ptr(self) -> bool { |
| matches!(self.kind(), FnPtr(_)) |
| } |
| |
| #[inline] |
| pub fn is_impl_trait(self) -> bool { |
| matches!(self.kind(), Alias(ty::Opaque, ..)) |
| } |
| |
| #[inline] |
| pub fn ty_adt_def(self) -> Option<AdtDef<'tcx>> { |
| match self.kind() { |
| Adt(adt, _) => Some(*adt), |
| _ => None, |
| } |
| } |
| |
| /// Iterates over tuple fields. |
| /// Panics when called on anything but a tuple. |
| #[inline] |
| pub fn tuple_fields(self) -> &'tcx List<Ty<'tcx>> { |
| match self.kind() { |
| Tuple(substs) => substs, |
| _ => bug!("tuple_fields called on non-tuple"), |
| } |
| } |
| |
| /// If the type contains variants, returns the valid range of variant indices. |
| // |
| // FIXME: This requires the optimized MIR in the case of generators. |
| #[inline] |
| pub fn variant_range(self, tcx: TyCtxt<'tcx>) -> Option<Range<VariantIdx>> { |
| match self.kind() { |
| TyKind::Adt(adt, _) => Some(adt.variant_range()), |
| TyKind::Generator(def_id, substs, _) => { |
| Some(substs.as_generator().variant_range(*def_id, tcx)) |
| } |
| _ => None, |
| } |
| } |
| |
| /// If the type contains variants, returns the variant for `variant_index`. |
| /// Panics if `variant_index` is out of range. |
| // |
| // FIXME: This requires the optimized MIR in the case of generators. |
| #[inline] |
| pub fn discriminant_for_variant( |
| self, |
| tcx: TyCtxt<'tcx>, |
| variant_index: VariantIdx, |
| ) -> Option<Discr<'tcx>> { |
| match self.kind() { |
| TyKind::Adt(adt, _) if adt.variants().is_empty() => { |
| // This can actually happen during CTFE, see |
| // https://github.com/rust-lang/rust/issues/89765. |
| None |
| } |
| TyKind::Adt(adt, _) if adt.is_enum() => { |
| Some(adt.discriminant_for_variant(tcx, variant_index)) |
| } |
| TyKind::Generator(def_id, substs, _) => { |
| Some(substs.as_generator().discriminant_for_variant(*def_id, tcx, variant_index)) |
| } |
| _ => None, |
| } |
| } |
| |
| /// Returns the type of the discriminant of this type. |
| pub fn discriminant_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> { |
| match self.kind() { |
| ty::Adt(adt, _) if adt.is_enum() => adt.repr().discr_type().to_ty(tcx), |
| ty::Generator(_, substs, _) => substs.as_generator().discr_ty(tcx), |
| |
| ty::Param(_) | ty::Alias(..) | ty::Infer(ty::TyVar(_)) => { |
| let assoc_items = tcx.associated_item_def_ids( |
| tcx.require_lang_item(hir::LangItem::DiscriminantKind, None), |
| ); |
| tcx.mk_projection(assoc_items[0], tcx.mk_substs(&[self.into()])) |
| } |
| |
| ty::Bool |
| | ty::Char |
| | ty::Int(_) |
| | ty::Uint(_) |
| | ty::Float(_) |
| | ty::Adt(..) |
| | ty::Foreign(_) |
| | ty::Str |
| | ty::Array(..) |
| | ty::Slice(_) |
| | ty::RawPtr(_) |
| | ty::Ref(..) |
| | ty::FnDef(..) |
| | ty::FnPtr(..) |
| | ty::Dynamic(..) |
| | ty::Closure(..) |
| | ty::GeneratorWitness(..) |
| | ty::GeneratorWitnessMIR(..) |
| | ty::Never |
| | ty::Tuple(_) |
| | ty::Error(_) |
| | ty::Infer(IntVar(_) | FloatVar(_)) => tcx.types.u8, |
| |
| ty::Bound(..) |
| | ty::Placeholder(_) |
| | ty::Infer(FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => { |
| bug!("`discriminant_ty` applied to unexpected type: {:?}", self) |
| } |
| } |
| } |
| |
| /// Returns the type of metadata for (potentially fat) pointers to this type, |
| /// and a boolean signifying if this is conditional on this type being `Sized`. |
| pub fn ptr_metadata_ty( |
| self, |
| tcx: TyCtxt<'tcx>, |
| normalize: impl FnMut(Ty<'tcx>) -> Ty<'tcx>, |
| ) -> (Ty<'tcx>, bool) { |
| let tail = tcx.struct_tail_with_normalize(self, normalize, || {}); |
| match tail.kind() { |
| // Sized types |
| ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) |
| | ty::Uint(_) |
| | ty::Int(_) |
| | ty::Bool |
| | ty::Float(_) |
| | ty::FnDef(..) |
| | ty::FnPtr(_) |
| | ty::RawPtr(..) |
| | ty::Char |
| | ty::Ref(..) |
| | ty::Generator(..) |
| | ty::GeneratorWitness(..) |
| | ty::GeneratorWitnessMIR(..) |
| | ty::Array(..) |
| | ty::Closure(..) |
| | ty::Never |
| | ty::Error(_) |
| // Extern types have metadata = (). |
| | ty::Foreign(..) |
| // If returned by `struct_tail_without_normalization` this is a unit struct |
| // without any fields, or not a struct, and therefore is Sized. |
| | ty::Adt(..) |
| // If returned by `struct_tail_without_normalization` this is the empty tuple, |
| // a.k.a. unit type, which is Sized |
| | ty::Tuple(..) => (tcx.types.unit, false), |
| |
| ty::Str | ty::Slice(_) => (tcx.types.usize, false), |
| ty::Dynamic(..) => { |
| let dyn_metadata = tcx.require_lang_item(LangItem::DynMetadata, None); |
| (tcx.type_of(dyn_metadata).subst(tcx, &[tail.into()]), false) |
| }, |
| |
| // type parameters only have unit metadata if they're sized, so return true |
| // to make sure we double check this during confirmation |
| ty::Param(_) | ty::Alias(..) => (tcx.types.unit, true), |
| |
| ty::Infer(ty::TyVar(_)) |
| | ty::Bound(..) |
| | ty::Placeholder(..) |
| | ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => { |
| bug!("`ptr_metadata_ty` applied to unexpected type: {:?} (tail = {:?})", self, tail) |
| } |
| } |
| } |
| |
| /// When we create a closure, we record its kind (i.e., what trait |
| /// it implements) into its `ClosureSubsts` using a type |
| /// parameter. This is kind of a phantom type, except that the |
| /// most convenient thing for us to are the integral types. This |
| /// function converts such a special type into the closure |
| /// kind. To go the other way, use `closure_kind.to_ty(tcx)`. |
| /// |
| /// Note that during type checking, we use an inference variable |
| /// to represent the closure kind, because it has not yet been |
| /// inferred. Once upvar inference (in `rustc_hir_analysis/src/check/upvar.rs`) |
| /// is complete, that type variable will be unified. |
| pub fn to_opt_closure_kind(self) -> Option<ty::ClosureKind> { |
| match self.kind() { |
| Int(int_ty) => match int_ty { |
| ty::IntTy::I8 => Some(ty::ClosureKind::Fn), |
| ty::IntTy::I16 => Some(ty::ClosureKind::FnMut), |
| ty::IntTy::I32 => Some(ty::ClosureKind::FnOnce), |
| _ => bug!("cannot convert type `{:?}` to a closure kind", self), |
| }, |
| |
| // "Bound" types appear in canonical queries when the |
| // closure type is not yet known |
| Bound(..) | Infer(_) => None, |
| |
| Error(_) => Some(ty::ClosureKind::Fn), |
| |
| _ => bug!("cannot convert type `{:?}` to a closure kind", self), |
| } |
| } |
| |
| /// Fast path helper for testing if a type is `Sized`. |
| /// |
| /// Returning true means the type is known to be sized. Returning |
| /// `false` means nothing -- could be sized, might not be. |
| /// |
| /// Note that we could never rely on the fact that a type such as `[_]` is |
| /// trivially `!Sized` because we could be in a type environment with a |
| /// bound such as `[_]: Copy`. A function with such a bound obviously never |
| /// can be called, but that doesn't mean it shouldn't typecheck. This is why |
| /// this method doesn't return `Option<bool>`. |
| pub fn is_trivially_sized(self, tcx: TyCtxt<'tcx>) -> bool { |
| match self.kind() { |
| ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) |
| | ty::Uint(_) |
| | ty::Int(_) |
| | ty::Bool |
| | ty::Float(_) |
| | ty::FnDef(..) |
| | ty::FnPtr(_) |
| | ty::RawPtr(..) |
| | ty::Char |
| | ty::Ref(..) |
| | ty::Generator(..) |
| | ty::GeneratorWitness(..) |
| | ty::GeneratorWitnessMIR(..) |
| | ty::Array(..) |
| | ty::Closure(..) |
| | ty::Never |
| | ty::Error(_) => true, |
| |
| ty::Str | ty::Slice(_) | ty::Dynamic(..) | ty::Foreign(..) => false, |
| |
| ty::Tuple(tys) => tys.iter().all(|ty| ty.is_trivially_sized(tcx)), |
| |
| ty::Adt(def, _substs) => def.sized_constraint(tcx).0.is_empty(), |
| |
| ty::Alias(..) | ty::Param(_) => false, |
| |
| ty::Infer(ty::TyVar(_)) => false, |
| |
| ty::Bound(..) |
| | ty::Placeholder(..) |
| | ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => { |
| bug!("`is_trivially_sized` applied to unexpected type: {:?}", self) |
| } |
| } |
| } |
| |
| /// Fast path helper for primitives which are always `Copy` and which |
| /// have a side-effect-free `Clone` impl. |
| /// |
| /// Returning true means the type is known to be pure and `Copy+Clone`. |
| /// Returning `false` means nothing -- could be `Copy`, might not be. |
| /// |
| /// This is mostly useful for optimizations, as there are the types |
| /// on which we can replace cloning with dereferencing. |
| pub fn is_trivially_pure_clone_copy(self) -> bool { |
| match self.kind() { |
| ty::Bool | ty::Char | ty::Never => true, |
| |
| // These aren't even `Clone` |
| ty::Str | ty::Slice(..) | ty::Foreign(..) | ty::Dynamic(..) => false, |
| |
| ty::Infer(ty::InferTy::FloatVar(_) | ty::InferTy::IntVar(_)) |
| | ty::Int(..) |
| | ty::Uint(..) |
| | ty::Float(..) => true, |
| |
| // The voldemort ZSTs are fine. |
| ty::FnDef(..) => true, |
| |
| ty::Array(element_ty, _len) => element_ty.is_trivially_pure_clone_copy(), |
| |
| // A 100-tuple isn't "trivial", so doing this only for reasonable sizes. |
| ty::Tuple(field_tys) => { |
| field_tys.len() <= 3 && field_tys.iter().all(Self::is_trivially_pure_clone_copy) |
| } |
| |
| // Sometimes traits aren't implemented for every ABI or arity, |
| // because we can't be generic over everything yet. |
| ty::FnPtr(..) => false, |
| |
| // Definitely absolutely not copy. |
| ty::Ref(_, _, hir::Mutability::Mut) => false, |
| |
| // Thin pointers & thin shared references are pure-clone-copy, but for |
| // anything with custom metadata it might be more complicated. |
| ty::Ref(_, _, hir::Mutability::Not) | ty::RawPtr(..) => false, |
| |
| ty::Generator(..) | ty::GeneratorWitness(..) | ty::GeneratorWitnessMIR(..) => false, |
| |
| // Might be, but not "trivial" so just giving the safe answer. |
| ty::Adt(..) | ty::Closure(..) => false, |
| |
| // Needs normalization or revealing to determine, so no is the safe answer. |
| ty::Alias(..) => false, |
| |
| ty::Param(..) | ty::Infer(..) | ty::Error(..) => false, |
| |
| ty::Bound(..) | ty::Placeholder(..) => { |
| bug!("`is_trivially_pure_clone_copy` applied to unexpected type: {:?}", self); |
| } |
| } |
| } |
| |
| /// If `self` is a primitive, return its [`Symbol`]. |
| pub fn primitive_symbol(self) -> Option<Symbol> { |
| match self.kind() { |
| ty::Bool => Some(sym::bool), |
| ty::Char => Some(sym::char), |
| ty::Float(f) => match f { |
| ty::FloatTy::F32 => Some(sym::f32), |
| ty::FloatTy::F64 => Some(sym::f64), |
| }, |
| ty::Int(f) => match f { |
| ty::IntTy::Isize => Some(sym::isize), |
| ty::IntTy::I8 => Some(sym::i8), |
| ty::IntTy::I16 => Some(sym::i16), |
| ty::IntTy::I32 => Some(sym::i32), |
| ty::IntTy::I64 => Some(sym::i64), |
| ty::IntTy::I128 => Some(sym::i128), |
| }, |
| ty::Uint(f) => match f { |
| ty::UintTy::Usize => Some(sym::usize), |
| ty::UintTy::U8 => Some(sym::u8), |
| ty::UintTy::U16 => Some(sym::u16), |
| ty::UintTy::U32 => Some(sym::u32), |
| ty::UintTy::U64 => Some(sym::u64), |
| ty::UintTy::U128 => Some(sym::u128), |
| }, |
| _ => None, |
| } |
| } |
| } |
| |
| /// Extra information about why we ended up with a particular variance. |
| /// This is only used to add more information to error messages, and |
| /// has no effect on soundness. While choosing the 'wrong' `VarianceDiagInfo` |
| /// may lead to confusing notes in error messages, it will never cause |
| /// a miscompilation or unsoundness. |
| /// |
| /// When in doubt, use `VarianceDiagInfo::default()` |
| #[derive(Copy, Clone, Debug, Default, PartialEq, Eq, PartialOrd, Ord)] |
| pub enum VarianceDiagInfo<'tcx> { |
| /// No additional information - this is the default. |
| /// We will not add any additional information to error messages. |
| #[default] |
| None, |
| /// We switched our variance because a generic argument occurs inside |
| /// the invariant generic argument of another type. |
| Invariant { |
| /// The generic type containing the generic parameter |
| /// that changes the variance (e.g. `*mut T`, `MyStruct<T>`) |
| ty: Ty<'tcx>, |
| /// The index of the generic parameter being used |
| /// (e.g. `0` for `*mut T`, `1` for `MyStruct<'CovariantParam, 'InvariantParam>`) |
| param_index: u32, |
| }, |
| } |
| |
| impl<'tcx> VarianceDiagInfo<'tcx> { |
| /// Mirrors `Variance::xform` - used to 'combine' the existing |
| /// and new `VarianceDiagInfo`s when our variance changes. |
| pub fn xform(self, other: VarianceDiagInfo<'tcx>) -> VarianceDiagInfo<'tcx> { |
| // For now, just use the first `VarianceDiagInfo::Invariant` that we see |
| match self { |
| VarianceDiagInfo::None => other, |
| VarianceDiagInfo::Invariant { .. } => self, |
| } |
| } |
| } |