2231 lines
78 KiB
Rust
2231 lines
78 KiB
Rust
//! This module contains `TyKind` and its major components.
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#![allow(rustc::usage_of_ty_tykind)]
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use self::TyKind::*;
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use crate::infer::canonical::Canonical;
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use crate::ty::subst::{GenericArg, InternalSubsts, Subst, SubstsRef};
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use crate::ty::InferTy::{self, *};
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use crate::ty::{
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self, AdtDef, DefIdTree, Discr, Ty, TyCtxt, TypeFlags, TypeFoldable, WithConstness,
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};
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use crate::ty::{DelaySpanBugEmitted, List, ParamEnv, TyS};
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use polonius_engine::Atom;
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use rustc_data_structures::captures::Captures;
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use rustc_hir as hir;
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use rustc_hir::def_id::DefId;
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use rustc_index::vec::Idx;
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use rustc_macros::HashStable;
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use rustc_span::symbol::{kw, Symbol};
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use rustc_target::abi::VariantIdx;
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use rustc_target::spec::abi;
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use std::borrow::Cow;
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use std::cmp::Ordering;
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use std::marker::PhantomData;
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use std::ops::Range;
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use ty::util::IntTypeExt;
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#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
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#[derive(HashStable, TypeFoldable, Lift)]
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pub struct TypeAndMut<'tcx> {
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pub ty: Ty<'tcx>,
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pub mutbl: hir::Mutability,
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}
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#[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash, TyEncodable, TyDecodable, Copy)]
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#[derive(HashStable)]
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/// A "free" region `fr` can be interpreted as "some region
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/// at least as big as the scope `fr.scope`".
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pub struct FreeRegion {
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pub scope: DefId,
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pub bound_region: BoundRegionKind,
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}
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#[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash, TyEncodable, TyDecodable, Copy)]
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#[derive(HashStable)]
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pub enum BoundRegionKind {
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/// An anonymous region parameter for a given fn (&T)
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BrAnon(u32),
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/// Named region parameters for functions (a in &'a T)
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///
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/// The `DefId` is needed to distinguish free regions in
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/// the event of shadowing.
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BrNamed(DefId, Symbol),
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/// Anonymous region for the implicit env pointer parameter
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/// to a closure
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BrEnv,
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}
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#[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, Debug, PartialOrd, Ord)]
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#[derive(HashStable)]
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pub struct BoundRegion {
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pub kind: BoundRegionKind,
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}
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impl BoundRegion {
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/// When canonicalizing, we replace unbound inference variables and free
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/// regions with anonymous late bound regions. This method asserts that
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/// we have an anonymous late bound region, which hence may refer to
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/// a canonical variable.
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pub fn assert_bound_var(&self) -> BoundVar {
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match self.kind {
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BoundRegionKind::BrAnon(var) => BoundVar::from_u32(var),
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_ => bug!("bound region is not anonymous"),
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}
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}
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}
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impl BoundRegionKind {
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pub fn is_named(&self) -> bool {
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match *self {
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BoundRegionKind::BrNamed(_, name) => name != kw::UnderscoreLifetime,
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_ => false,
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}
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}
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}
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/// Defines the kinds of types.
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///
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/// N.B., if you change this, you'll probably want to change the corresponding
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/// AST structure in `librustc_ast/ast.rs` as well.
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#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable, Debug)]
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#[derive(HashStable)]
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#[rustc_diagnostic_item = "TyKind"]
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pub enum TyKind<'tcx> {
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/// The primitive boolean type. Written as `bool`.
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Bool,
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/// The primitive character type; holds a Unicode scalar value
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/// (a non-surrogate code point). Written as `char`.
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Char,
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/// A primitive signed integer type. For example, `i32`.
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Int(ty::IntTy),
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/// A primitive unsigned integer type. For example, `u32`.
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Uint(ty::UintTy),
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/// A primitive floating-point type. For example, `f64`.
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Float(ty::FloatTy),
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/// Algebraic data types (ADT). For example: structures, enumerations and unions.
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///
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/// InternalSubsts here, possibly against intuition, *may* contain `Param`s.
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/// That is, even after substitution it is possible that there are type
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/// variables. This happens when the `Adt` corresponds to an ADT
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/// definition and not a concrete use of it.
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Adt(&'tcx AdtDef, SubstsRef<'tcx>),
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/// An unsized FFI type that is opaque to Rust. Written as `extern type T`.
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Foreign(DefId),
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/// The pointee of a string slice. Written as `str`.
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Str,
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/// An array with the given length. Written as `[T; n]`.
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Array(Ty<'tcx>, &'tcx ty::Const<'tcx>),
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/// The pointee of an array slice. Written as `[T]`.
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Slice(Ty<'tcx>),
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/// A raw pointer. Written as `*mut T` or `*const T`
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RawPtr(TypeAndMut<'tcx>),
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/// A reference; a pointer with an associated lifetime. Written as
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/// `&'a mut T` or `&'a T`.
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Ref(Region<'tcx>, Ty<'tcx>, hir::Mutability),
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/// The anonymous type of a function declaration/definition. Each
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/// function has a unique type, which is output (for a function
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/// named `foo` returning an `i32`) as `fn() -> i32 {foo}`.
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///
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/// For example the type of `bar` here:
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///
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/// ```rust
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/// fn foo() -> i32 { 1 }
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/// let bar = foo; // bar: fn() -> i32 {foo}
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/// ```
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FnDef(DefId, SubstsRef<'tcx>),
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/// A pointer to a function. Written as `fn() -> i32`.
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///
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/// For example the type of `bar` here:
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///
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/// ```rust
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/// fn foo() -> i32 { 1 }
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/// let bar: fn() -> i32 = foo;
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/// ```
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FnPtr(PolyFnSig<'tcx>),
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/// A trait, defined with `trait`.
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Dynamic(&'tcx List<Binder<ExistentialPredicate<'tcx>>>, ty::Region<'tcx>),
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/// The anonymous type of a closure. Used to represent the type of
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/// `|a| a`.
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Closure(DefId, SubstsRef<'tcx>),
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/// The anonymous type of a generator. Used to represent the type of
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/// `|a| yield a`.
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Generator(DefId, SubstsRef<'tcx>, hir::Movability),
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/// A type representing the types stored inside a generator.
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/// This should only appear in GeneratorInteriors.
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GeneratorWitness(Binder<&'tcx List<Ty<'tcx>>>),
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/// The never type `!`.
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Never,
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/// A tuple type. For example, `(i32, bool)`.
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/// Use `TyS::tuple_fields` to iterate over the field types.
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Tuple(SubstsRef<'tcx>),
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/// The projection of an associated type. For example,
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/// `<T as Trait<..>>::N`.
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Projection(ProjectionTy<'tcx>),
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/// Opaque (`impl Trait`) type found in a return type.
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/// The `DefId` comes either from
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/// * the `impl Trait` ast::Ty node,
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/// * or the `type Foo = impl Trait` declaration
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/// The substitutions are for the generics of the function in question.
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/// After typeck, the concrete type can be found in the `types` map.
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Opaque(DefId, SubstsRef<'tcx>),
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/// A type parameter; for example, `T` in `fn f<T>(x: T) {}`.
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Param(ParamTy),
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/// Bound type variable, used only when preparing a trait query.
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Bound(ty::DebruijnIndex, BoundTy),
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/// A placeholder type - universally quantified higher-ranked type.
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Placeholder(ty::PlaceholderType),
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/// A type variable used during type checking.
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Infer(InferTy),
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/// A placeholder for a type which could not be computed; this is
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/// propagated to avoid useless error messages.
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Error(DelaySpanBugEmitted),
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}
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impl TyKind<'tcx> {
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#[inline]
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pub fn is_primitive(&self) -> bool {
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matches!(self, Bool | Char | Int(_) | Uint(_) | Float(_))
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}
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/// Get the article ("a" or "an") to use with this type.
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pub fn article(&self) -> &'static str {
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match self {
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Int(_) | Float(_) | Array(_, _) => "an",
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Adt(def, _) if def.is_enum() => "an",
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// This should never happen, but ICEing and causing the user's code
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// to not compile felt too harsh.
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Error(_) => "a",
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_ => "a",
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}
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}
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}
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// `TyKind` is used a lot. Make sure it doesn't unintentionally get bigger.
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#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
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static_assert_size!(TyKind<'_>, 24);
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/// A closure can be modeled as a struct that looks like:
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///
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/// struct Closure<'l0...'li, T0...Tj, CK, CS, U>(...U);
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///
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/// where:
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///
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/// - 'l0...'li and T0...Tj are the generic parameters
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/// in scope on the function that defined the closure,
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/// - CK represents the *closure kind* (Fn vs FnMut vs FnOnce). This
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/// is rather hackily encoded via a scalar type. See
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/// `TyS::to_opt_closure_kind` for details.
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/// - CS represents the *closure signature*, representing as a `fn()`
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/// type. For example, `fn(u32, u32) -> u32` would mean that the closure
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/// implements `CK<(u32, u32), Output = u32>`, where `CK` is the trait
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/// specified above.
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/// - U is a type parameter representing the types of its upvars, tupled up
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/// (borrowed, if appropriate; that is, if an U field represents a by-ref upvar,
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/// and the up-var has the type `Foo`, then that field of U will be `&Foo`).
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///
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/// So, for example, given this function:
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///
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/// fn foo<'a, T>(data: &'a mut T) {
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/// do(|| data.count += 1)
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/// }
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///
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/// the type of the closure would be something like:
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///
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/// struct Closure<'a, T, U>(...U);
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///
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/// Note that the type of the upvar is not specified in the struct.
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/// You may wonder how the impl would then be able to use the upvar,
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/// if it doesn't know it's type? The answer is that the impl is
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/// (conceptually) not fully generic over Closure but rather tied to
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/// instances with the expected upvar types:
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///
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/// impl<'b, 'a, T> FnMut() for Closure<'a, T, (&'b mut &'a mut T,)> {
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/// ...
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/// }
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///
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/// You can see that the *impl* fully specified the type of the upvar
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/// and thus knows full well that `data` has type `&'b mut &'a mut T`.
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/// (Here, I am assuming that `data` is mut-borrowed.)
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///
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/// Now, the last question you may ask is: Why include the upvar types
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/// in an extra type parameter? The reason for this design is that the
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/// upvar types can reference lifetimes that are internal to the
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/// creating function. In my example above, for example, the lifetime
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/// `'b` represents the scope of the closure itself; this is some
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/// subset of `foo`, probably just the scope of the call to the to
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/// `do()`. If we just had the lifetime/type parameters from the
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/// enclosing function, we couldn't name this lifetime `'b`. Note that
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/// there can also be lifetimes in the types of the upvars themselves,
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/// if one of them happens to be a reference to something that the
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/// creating fn owns.
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///
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/// OK, you say, so why not create a more minimal set of parameters
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/// that just includes the extra lifetime parameters? The answer is
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/// primarily that it would be hard --- we don't know at the time when
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/// we create the closure type what the full types of the upvars are,
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/// nor do we know which are borrowed and which are not. In this
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/// design, we can just supply a fresh type parameter and figure that
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/// out later.
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///
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/// All right, you say, but why include the type parameters from the
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/// original function then? The answer is that codegen may need them
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/// when monomorphizing, and they may not appear in the upvars. A
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/// closure could capture no variables but still make use of some
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/// in-scope type parameter with a bound (e.g., if our example above
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/// had an extra `U: Default`, and the closure called `U::default()`).
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///
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/// There is another reason. This design (implicitly) prohibits
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/// closures from capturing themselves (except via a trait
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/// object). This simplifies closure inference considerably, since it
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/// means that when we infer the kind of a closure or its upvars, we
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/// don't have to handle cycles where the decisions we make for
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/// closure C wind up influencing the decisions we ought to make for
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/// closure C (which would then require fixed point iteration to
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/// handle). Plus it fixes an ICE. :P
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///
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/// ## Generators
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///
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/// Generators are handled similarly in `GeneratorSubsts`. The set of
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/// type parameters is similar, but `CK` and `CS` are replaced by the
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/// following type parameters:
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///
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/// * `GS`: The generator's "resume type", which is the type of the
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/// argument passed to `resume`, and the type of `yield` expressions
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/// inside the generator.
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/// * `GY`: The "yield type", which is the type of values passed to
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/// `yield` inside the generator.
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/// * `GR`: The "return type", which is the type of value returned upon
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/// completion of the generator.
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/// * `GW`: The "generator witness".
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#[derive(Copy, Clone, Debug, TypeFoldable)]
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pub struct ClosureSubsts<'tcx> {
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/// Lifetime and type parameters from the enclosing function,
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/// concatenated with a tuple containing the types of the upvars.
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///
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/// These are separated out because codegen wants to pass them around
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/// when monomorphizing.
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pub substs: SubstsRef<'tcx>,
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}
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/// Struct returned by `split()`.
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pub struct ClosureSubstsParts<'tcx, T> {
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pub parent_substs: &'tcx [GenericArg<'tcx>],
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pub closure_kind_ty: T,
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pub closure_sig_as_fn_ptr_ty: T,
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pub tupled_upvars_ty: T,
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}
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impl<'tcx> ClosureSubsts<'tcx> {
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/// Construct `ClosureSubsts` from `ClosureSubstsParts`, containing `Substs`
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/// for the closure parent, alongside additional closure-specific components.
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pub fn new(
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tcx: TyCtxt<'tcx>,
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parts: ClosureSubstsParts<'tcx, Ty<'tcx>>,
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) -> ClosureSubsts<'tcx> {
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ClosureSubsts {
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substs: tcx.mk_substs(
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parts.parent_substs.iter().copied().chain(
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[parts.closure_kind_ty, parts.closure_sig_as_fn_ptr_ty, parts.tupled_upvars_ty]
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.iter()
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.map(|&ty| ty.into()),
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),
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),
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}
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}
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/// Divides the closure substs into their respective components.
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/// The ordering assumed here must match that used by `ClosureSubsts::new` above.
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fn split(self) -> ClosureSubstsParts<'tcx, GenericArg<'tcx>> {
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match self.substs[..] {
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[ref parent_substs @ .., closure_kind_ty, closure_sig_as_fn_ptr_ty, tupled_upvars_ty] => {
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ClosureSubstsParts {
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parent_substs,
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closure_kind_ty,
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closure_sig_as_fn_ptr_ty,
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tupled_upvars_ty,
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}
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}
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_ => bug!("closure substs missing synthetics"),
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}
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}
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/// Returns `true` only if enough of the synthetic types are known to
|
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/// allow using all of the methods on `ClosureSubsts` without panicking.
|
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///
|
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/// Used primarily by `ty::print::pretty` to be able to handle closure
|
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/// types that haven't had their synthetic types substituted in.
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pub fn is_valid(self) -> bool {
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self.substs.len() >= 3
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&& matches!(self.split().tupled_upvars_ty.expect_ty().kind(), Tuple(_))
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}
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/// Returns the substitutions of the closure's parent.
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pub fn parent_substs(self) -> &'tcx [GenericArg<'tcx>] {
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self.split().parent_substs
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}
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/// Returns an iterator over the list of types of captured paths by the closure.
|
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/// In case there was a type error in figuring out the types of the captured path, an
|
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/// empty iterator is returned.
|
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#[inline]
|
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pub fn upvar_tys(self) -> impl Iterator<Item = Ty<'tcx>> + 'tcx {
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match self.tupled_upvars_ty().kind() {
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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]
|
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pub fn tupled_upvars_ty(self) -> Ty<'tcx> {
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self.split().tupled_upvars_ty.expect_ty()
|
||
}
|
||
|
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/// 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()
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||
}
|
||
|
||
/// 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_typeck::check::closure`.
|
||
pub fn sig_as_fn_ptr_ty(self) -> Ty<'tcx> {
|
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self.split().closure_sig_as_fn_ptr_ty.expect_ty()
|
||
}
|
||
|
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/// 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()),
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Similar to `ClosureSubsts`; see the above documentation for more.
|
||
#[derive(Copy, Clone, Debug, TypeFoldable)]
|
||
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(
|
||
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 = impl 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| layout.field_tys[*field].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)]
|
||
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(),
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Ord, Eq, Hash, TyEncodable, TyDecodable)]
|
||
#[derive(HashStable, TypeFoldable)]
|
||
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.item_def_id).cmp(&tcx.def_path_hash(b.item_def_id))
|
||
}
|
||
(AutoTrait(ref a), AutoTrait(ref b)) => {
|
||
tcx.trait_def(*a).def_path_hash.cmp(&tcx.trait_def(*b).def_path_hash)
|
||
}
|
||
(Trait(_), _) => Ordering::Less,
|
||
(Projection(_), Trait(_)) => Ordering::Greater,
|
||
(Projection(_), _) => Ordering::Less,
|
||
(AutoTrait(_), _) => Ordering::Greater,
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'tcx> Binder<ExistentialPredicate<'tcx>> {
|
||
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 trait_ref = self.rebind(ty::TraitRef {
|
||
def_id: did,
|
||
substs: tcx.mk_substs_trait(self_ty, &[]),
|
||
});
|
||
trait_ref.without_const().to_predicate(tcx)
|
||
}
|
||
}
|
||
}
|
||
}
|
||
|
||
impl<'tcx> List<ty::Binder<ExistentialPredicate<'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<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<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> + '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:
|
||
///
|
||
/// 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, Hash, TyEncodable, TyDecodable)]
|
||
#[derive(HashStable, TypeFoldable)]
|
||
pub struct TraitRef<'tcx> {
|
||
pub def_id: DefId,
|
||
pub substs: SubstsRef<'tcx>,
|
||
}
|
||
|
||
impl<'tcx> TraitRef<'tcx> {
|
||
pub fn new(def_id: DefId, substs: SubstsRef<'tcx>) -> TraitRef<'tcx> {
|
||
TraitRef { def_id, substs }
|
||
}
|
||
|
||
/// 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) -> TraitRef<'tcx> {
|
||
TraitRef { def_id, substs: 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);
|
||
|
||
ty::TraitRef { def_id: trait_id, substs: tcx.intern_substs(&substs[..defs.params.len()]) }
|
||
}
|
||
}
|
||
|
||
pub type PolyTraitRef<'tcx> = Binder<TraitRef<'tcx>>;
|
||
|
||
impl<'tcx> PolyTraitRef<'tcx> {
|
||
pub fn self_ty(&self) -> Binder<Ty<'tcx>> {
|
||
self.map_bound_ref(|tr| tr.self_ty())
|
||
}
|
||
|
||
pub fn def_id(&self) -> DefId {
|
||
self.skip_binder().def_id
|
||
}
|
||
|
||
pub fn to_poly_trait_predicate(&self) -> ty::PolyTraitPredicate<'tcx> {
|
||
self.map_bound(|trait_ref| ty::TraitPredicate { trait_ref })
|
||
}
|
||
}
|
||
|
||
/// An existential reference to a trait, where `Self` is erased.
|
||
/// For example, the trait object `Trait<'a, 'b, X, Y>` is:
|
||
///
|
||
/// 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)]
|
||
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.intern_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());
|
||
|
||
ty::TraitRef { def_id: self.def_id, substs: tcx.mk_substs_trait(self_ty, self.substs) }
|
||
}
|
||
}
|
||
|
||
pub type PolyExistentialTraitRef<'tcx> = Binder<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))
|
||
}
|
||
}
|
||
|
||
/// 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<TraitRef>`). Note that when we instantiate,
|
||
/// erase, or otherwise "discharge" these bound vars, we change the
|
||
/// type from `Binder<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)]
|
||
pub struct Binder<T>(T);
|
||
|
||
impl<T> Binder<T> {
|
||
/// 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.
|
||
pub fn dummy<'tcx>(value: T) -> Binder<T>
|
||
where
|
||
T: TypeFoldable<'tcx>,
|
||
{
|
||
debug_assert!(!value.has_escaping_bound_vars());
|
||
Binder(value)
|
||
}
|
||
|
||
/// Wraps `value` in a binder, binding higher-ranked vars (if any).
|
||
pub fn bind(value: T) -> Binder<T> {
|
||
Binder(value)
|
||
}
|
||
|
||
/// Wraps `value` in a binder without actually binding any currently
|
||
/// unbound variables.
|
||
///
|
||
/// Note that this will shift all debrujin indices of escaping bound variables
|
||
/// by 1 to avoid accidential captures.
|
||
pub fn wrap_nonbinding(tcx: TyCtxt<'tcx>, value: T) -> Binder<T>
|
||
where
|
||
T: TypeFoldable<'tcx>,
|
||
{
|
||
if value.has_escaping_bound_vars() {
|
||
Binder::bind(super::fold::shift_vars(tcx, value, 1))
|
||
} else {
|
||
Binder::dummy(value)
|
||
}
|
||
}
|
||
|
||
/// 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 as_ref(&self) -> Binder<&T> {
|
||
Binder(&self.0)
|
||
}
|
||
|
||
pub fn map_bound_ref<F, U>(&self, f: F) -> Binder<U>
|
||
where
|
||
F: FnOnce(&T) -> U,
|
||
{
|
||
self.as_ref().map_bound(f)
|
||
}
|
||
|
||
pub fn map_bound<F, U>(self, f: F) -> Binder<U>
|
||
where
|
||
F: FnOnce(T) -> U,
|
||
{
|
||
Binder(f(self.0))
|
||
}
|
||
|
||
/// 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<U> {
|
||
Binder(value)
|
||
}
|
||
|
||
/// 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<'tcx>(self) -> Option<T>
|
||
where
|
||
T: TypeFoldable<'tcx>,
|
||
{
|
||
if self.0.has_escaping_bound_vars() { None } else { Some(self.skip_binder()) }
|
||
}
|
||
|
||
/// Given two things that have the same binder level,
|
||
/// and an operation that wraps on their contents, executes the operation
|
||
/// and then wraps its result.
|
||
///
|
||
/// `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 value.
|
||
pub fn fuse<U, F, R>(self, u: Binder<U>, f: F) -> Binder<R>
|
||
where
|
||
F: FnOnce(T, U) -> R,
|
||
{
|
||
Binder(f(self.0, u.0))
|
||
}
|
||
|
||
/// 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<U>, Binder<V>)
|
||
where
|
||
F: FnOnce(T) -> (U, V),
|
||
{
|
||
let (u, v) = f(self.0);
|
||
(Binder(u), Binder(v))
|
||
}
|
||
}
|
||
|
||
impl<T> Binder<Option<T>> {
|
||
pub fn transpose(self) -> Option<Binder<T>> {
|
||
self.0.map(Binder)
|
||
}
|
||
}
|
||
|
||
/// Represents the projection of an associated type. In explicit UFCS
|
||
/// form this would be written `<T as Trait<..>>::N`.
|
||
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
|
||
#[derive(HashStable, TypeFoldable)]
|
||
pub struct ProjectionTy<'tcx> {
|
||
/// The parameters of the associated item.
|
||
pub substs: SubstsRef<'tcx>,
|
||
|
||
/// The `DefId` of the `TraitItem` for the associated type `N`.
|
||
///
|
||
/// Note that this is not the `DefId` of the `TraitRef` containing this
|
||
/// associated type, which is in `tcx.associated_item(item_def_id).container`.
|
||
pub item_def_id: DefId,
|
||
}
|
||
|
||
impl<'tcx> ProjectionTy<'tcx> {
|
||
pub fn trait_def_id(&self, tcx: TyCtxt<'tcx>) -> DefId {
|
||
tcx.associated_item(self.item_def_id).container.id()
|
||
}
|
||
|
||
/// 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>]) {
|
||
let def_id = tcx.associated_item(self.item_def_id).container.id();
|
||
let trait_generics = tcx.generics_of(def_id);
|
||
(
|
||
ty::TraitRef { def_id, substs: 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);
|
||
ty::TraitRef { def_id, substs: self.substs.truncate_to(tcx, tcx.generics_of(def_id)) }
|
||
}
|
||
|
||
pub fn self_ty(&self) -> Ty<'tcx> {
|
||
self.substs.type_at(0)
|
||
}
|
||
}
|
||
|
||
#[derive(Copy, Clone, Debug, TypeFoldable)]
|
||
pub struct GenSig<'tcx> {
|
||
pub resume_ty: Ty<'tcx>,
|
||
pub yield_ty: Ty<'tcx>,
|
||
pub return_ty: Ty<'tcx>,
|
||
}
|
||
|
||
pub type PolyGenSig<'tcx> = Binder<GenSig<'tcx>>;
|
||
|
||
impl<'tcx> PolyGenSig<'tcx> {
|
||
pub fn resume_ty(&self) -> ty::Binder<Ty<'tcx>> {
|
||
self.map_bound_ref(|sig| sig.resume_ty)
|
||
}
|
||
pub fn yield_ty(&self) -> ty::Binder<Ty<'tcx>> {
|
||
self.map_bound_ref(|sig| sig.yield_ty)
|
||
}
|
||
pub fn return_ty(&self) -> ty::Binder<Ty<'tcx>> {
|
||
self.map_bound_ref(|sig| sig.return_ty)
|
||
}
|
||
}
|
||
|
||
/// 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)]
|
||
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<FnSig<'tcx>>;
|
||
|
||
impl<'tcx> PolyFnSig<'tcx> {
|
||
#[inline]
|
||
pub fn inputs(&self) -> Binder<&'tcx [Ty<'tcx>]> {
|
||
self.map_bound_ref(|fn_sig| fn_sig.inputs())
|
||
}
|
||
#[inline]
|
||
pub fn input(&self, index: usize) -> ty::Binder<Ty<'tcx>> {
|
||
self.map_bound_ref(|fn_sig| fn_sig.inputs()[index])
|
||
}
|
||
pub fn inputs_and_output(&self) -> ty::Binder<&'tcx List<Ty<'tcx>>> {
|
||
self.map_bound_ref(|fn_sig| fn_sig.inputs_and_output)
|
||
}
|
||
#[inline]
|
||
pub fn output(&self) -> ty::Binder<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<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_self() -> ParamTy {
|
||
ParamTy::new(0, kw::SelfUpper)
|
||
}
|
||
|
||
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)
|
||
}
|
||
}
|
||
|
||
#[derive(Copy, Clone, Hash, TyEncodable, TyDecodable, Eq, PartialEq, Ord, PartialOrd)]
|
||
#[derive(HashStable)]
|
||
pub struct ParamConst {
|
||
pub index: u32,
|
||
pub name: Symbol,
|
||
}
|
||
|
||
impl<'tcx> 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)
|
||
}
|
||
|
||
pub fn to_const(self, tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> &'tcx ty::Const<'tcx> {
|
||
tcx.mk_const_param(self.index, self.name, ty)
|
||
}
|
||
}
|
||
|
||
pub type Region<'tcx> = &'tcx RegionKind;
|
||
|
||
/// Representation of regions. Note that the NLL checker uses a distinct
|
||
/// representation of regions. For this reason, it internally replaces all the
|
||
/// regions with inference variables -- the index of the variable is then used
|
||
/// to index into internal NLL data structures. See `rustc_mir::borrow_check`
|
||
/// module for more information.
|
||
///
|
||
/// ## The Region lattice within a given function
|
||
///
|
||
/// In general, the region lattice looks like
|
||
///
|
||
/// ```
|
||
/// static ----------+-----...------+ (greatest)
|
||
/// | | |
|
||
/// early-bound and | |
|
||
/// free regions | |
|
||
/// | | |
|
||
/// | | |
|
||
/// empty(root) placeholder(U1) |
|
||
/// | / |
|
||
/// | / placeholder(Un)
|
||
/// empty(U1) -- /
|
||
/// | /
|
||
/// ... /
|
||
/// | /
|
||
/// empty(Un) -------- (smallest)
|
||
/// ```
|
||
///
|
||
/// Early-bound/free regions are the named lifetimes in scope from the
|
||
/// function declaration. They have relationships to one another
|
||
/// determined based on the declared relationships from the
|
||
/// function.
|
||
///
|
||
/// Note that inference variables and bound regions are not included
|
||
/// in this diagram. In the case of inference variables, they should
|
||
/// be inferred to some other region from the diagram. In the case of
|
||
/// bound regions, they are excluded because they don't make sense to
|
||
/// include -- the diagram indicates the relationship between free
|
||
/// regions.
|
||
///
|
||
/// ## Inference variables
|
||
///
|
||
/// During region inference, we sometimes create inference variables,
|
||
/// represented as `ReVar`. These will be inferred by the code in
|
||
/// `infer::lexical_region_resolve` to some free region from the
|
||
/// lattice above (the minimal region that meets the
|
||
/// constraints).
|
||
///
|
||
/// During NLL checking, where regions are defined differently, we
|
||
/// also use `ReVar` -- in that case, the index is used to index into
|
||
/// the NLL region checker's data structures. The variable may in fact
|
||
/// represent either a free region or an inference variable, in that
|
||
/// case.
|
||
///
|
||
/// ## Bound Regions
|
||
///
|
||
/// These are regions that are stored behind a binder and must be substituted
|
||
/// with some concrete region before being used. There are two kind of
|
||
/// bound regions: early-bound, which are bound in an item's `Generics`,
|
||
/// and are substituted by a `InternalSubsts`, and late-bound, which are part of
|
||
/// higher-ranked types (e.g., `for<'a> fn(&'a ())`), and are substituted by
|
||
/// the likes of `liberate_late_bound_regions`. The distinction exists
|
||
/// because higher-ranked lifetimes aren't supported in all places. See [1][2].
|
||
///
|
||
/// Unlike `Param`s, bound regions are not supposed to exist "in the wild"
|
||
/// outside their binder, e.g., in types passed to type inference, and
|
||
/// should first be substituted (by placeholder regions, free regions,
|
||
/// or region variables).
|
||
///
|
||
/// ## Placeholder and Free Regions
|
||
///
|
||
/// One often wants to work with bound regions without knowing their precise
|
||
/// identity. For example, when checking a function, the lifetime of a borrow
|
||
/// can end up being assigned to some region parameter. In these cases,
|
||
/// it must be ensured that bounds on the region can't be accidentally
|
||
/// assumed without being checked.
|
||
///
|
||
/// To do this, we replace the bound regions with placeholder markers,
|
||
/// which don't satisfy any relation not explicitly provided.
|
||
///
|
||
/// There are two kinds of placeholder regions in rustc: `ReFree` and
|
||
/// `RePlaceholder`. When checking an item's body, `ReFree` is supposed
|
||
/// to be used. These also support explicit bounds: both the internally-stored
|
||
/// *scope*, which the region is assumed to outlive, as well as other
|
||
/// relations stored in the `FreeRegionMap`. Note that these relations
|
||
/// aren't checked when you `make_subregion` (or `eq_types`), only by
|
||
/// `resolve_regions_and_report_errors`.
|
||
///
|
||
/// When working with higher-ranked types, some region relations aren't
|
||
/// yet known, so you can't just call `resolve_regions_and_report_errors`.
|
||
/// `RePlaceholder` is designed for this purpose. In these contexts,
|
||
/// there's also the risk that some inference variable laying around will
|
||
/// get unified with your placeholder region: if you want to check whether
|
||
/// `for<'a> Foo<'_>: 'a`, and you substitute your bound region `'a`
|
||
/// with a placeholder region `'%a`, the variable `'_` would just be
|
||
/// instantiated to the placeholder region `'%a`, which is wrong because
|
||
/// the inference variable is supposed to satisfy the relation
|
||
/// *for every value of the placeholder region*. To ensure that doesn't
|
||
/// happen, you can use `leak_check`. This is more clearly explained
|
||
/// by the [rustc dev guide].
|
||
///
|
||
/// [1]: http://smallcultfollowing.com/babysteps/blog/2013/10/29/intermingled-parameter-lists/
|
||
/// [2]: http://smallcultfollowing.com/babysteps/blog/2013/11/04/intermingled-parameter-lists/
|
||
/// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/hrtb.html
|
||
#[derive(Clone, PartialEq, Eq, Hash, Copy, TyEncodable, TyDecodable, PartialOrd, Ord)]
|
||
pub enum RegionKind {
|
||
/// Region bound in a type or fn declaration which will be
|
||
/// substituted 'early' -- that is, at the same time when type
|
||
/// parameters are substituted.
|
||
ReEarlyBound(EarlyBoundRegion),
|
||
|
||
/// Region bound in a function scope, which will be substituted when the
|
||
/// function is called.
|
||
ReLateBound(ty::DebruijnIndex, BoundRegion),
|
||
|
||
/// When checking a function body, the types of all arguments and so forth
|
||
/// that refer to bound region parameters are modified to refer to free
|
||
/// region parameters.
|
||
ReFree(FreeRegion),
|
||
|
||
/// Static data that has an "infinite" lifetime. Top in the region lattice.
|
||
ReStatic,
|
||
|
||
/// A region variable. Should not exist after typeck.
|
||
ReVar(RegionVid),
|
||
|
||
/// A placeholder region -- basically, the higher-ranked version of `ReFree`.
|
||
/// Should not exist after typeck.
|
||
RePlaceholder(ty::PlaceholderRegion),
|
||
|
||
/// Empty lifetime is for data that is never accessed. We tag the
|
||
/// empty lifetime with a universe -- the idea is that we don't
|
||
/// want `exists<'a> { forall<'b> { 'b: 'a } }` to be satisfiable.
|
||
/// Therefore, the `'empty` in a universe `U` is less than all
|
||
/// regions visible from `U`, but not less than regions not visible
|
||
/// from `U`.
|
||
ReEmpty(ty::UniverseIndex),
|
||
|
||
/// Erased region, used by trait selection, in MIR and during codegen.
|
||
ReErased,
|
||
}
|
||
|
||
#[derive(Copy, Clone, PartialEq, Eq, Hash, TyEncodable, TyDecodable, Debug, PartialOrd, Ord)]
|
||
pub struct EarlyBoundRegion {
|
||
pub def_id: DefId,
|
||
pub index: u32,
|
||
pub name: Symbol,
|
||
}
|
||
|
||
/// A **`const`** **v**ariable **ID**.
|
||
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
|
||
pub struct ConstVid<'tcx> {
|
||
pub index: u32,
|
||
pub phantom: PhantomData<&'tcx ()>,
|
||
}
|
||
|
||
rustc_index::newtype_index! {
|
||
/// A **region** (lifetime) **v**ariable **ID**.
|
||
pub struct RegionVid {
|
||
DEBUG_FORMAT = custom,
|
||
}
|
||
}
|
||
|
||
impl Atom for RegionVid {
|
||
fn index(self) -> usize {
|
||
Idx::index(self)
|
||
}
|
||
}
|
||
|
||
rustc_index::newtype_index! {
|
||
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,
|
||
Param(Symbol),
|
||
}
|
||
|
||
impl From<BoundVar> for BoundTy {
|
||
fn from(var: BoundVar) -> Self {
|
||
BoundTy { var, kind: BoundTyKind::Anon }
|
||
}
|
||
}
|
||
|
||
/// A `ProjectionPredicate` for an `ExistentialTraitRef`.
|
||
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
|
||
#[derive(HashStable, TypeFoldable)]
|
||
pub struct ExistentialProjection<'tcx> {
|
||
pub item_def_id: DefId,
|
||
pub substs: SubstsRef<'tcx>,
|
||
pub ty: Ty<'tcx>,
|
||
}
|
||
|
||
pub type PolyExistentialProjection<'tcx> = Binder<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 a `exists T. T: Iterator` existential trait
|
||
/// reference.
|
||
pub fn trait_ref(&self, tcx: TyCtxt<'tcx>) -> ty::ExistentialTraitRef<'tcx> {
|
||
let def_id = tcx.associated_item(self.item_def_id).container.id();
|
||
let subst_count = tcx.generics_of(def_id).count() - 1;
|
||
let substs = tcx.intern_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: ty::ProjectionTy {
|
||
item_def_id: self.item_def_id,
|
||
substs: tcx.mk_substs_trait(self_ty, self.substs),
|
||
},
|
||
ty: self.ty,
|
||
}
|
||
}
|
||
|
||
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 {
|
||
item_def_id: projection_predicate.projection_ty.item_def_id,
|
||
substs: tcx.intern_substs(&projection_predicate.projection_ty.substs[1..]),
|
||
ty: projection_predicate.ty,
|
||
}
|
||
}
|
||
}
|
||
|
||
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().item_def_id
|
||
}
|
||
}
|
||
|
||
/// Region utilities
|
||
impl RegionKind {
|
||
/// Is this region named by the user?
|
||
pub fn has_name(&self) -> bool {
|
||
match *self {
|
||
RegionKind::ReEarlyBound(ebr) => ebr.has_name(),
|
||
RegionKind::ReLateBound(_, br) => br.kind.is_named(),
|
||
RegionKind::ReFree(fr) => fr.bound_region.is_named(),
|
||
RegionKind::ReStatic => true,
|
||
RegionKind::ReVar(..) => false,
|
||
RegionKind::RePlaceholder(placeholder) => placeholder.name.is_named(),
|
||
RegionKind::ReEmpty(_) => false,
|
||
RegionKind::ReErased => false,
|
||
}
|
||
}
|
||
|
||
#[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,
|
||
}
|
||
}
|
||
|
||
/// Adjusts any De Bruijn indices so as to make `to_binder` the
|
||
/// innermost binder. That is, if we have something bound at `to_binder`,
|
||
/// it will now be bound at INNERMOST. This is an appropriate thing to do
|
||
/// when moving a region out from inside binders:
|
||
///
|
||
/// ```
|
||
/// for<'a> fn(for<'b> for<'c> fn(&'a u32), _)
|
||
/// // Binder: D3 D2 D1 ^^
|
||
/// ```
|
||
///
|
||
/// Here, the region `'a` would have the De Bruijn index D3,
|
||
/// because it is the bound 3 binders out. However, if we wanted
|
||
/// to refer to that region `'a` in the second argument (the `_`),
|
||
/// those two binders would not be in scope. In that case, we
|
||
/// might invoke `shift_out_to_binder(D3)`. This would adjust the
|
||
/// De Bruijn index of `'a` to D1 (the innermost binder).
|
||
///
|
||
/// If we invoke `shift_out_to_binder` and the region is in fact
|
||
/// bound by one of the binders we are shifting out of, that is an
|
||
/// error (and should fail an assertion failure).
|
||
pub fn shifted_out_to_binder(&self, to_binder: ty::DebruijnIndex) -> RegionKind {
|
||
match *self {
|
||
ty::ReLateBound(debruijn, r) => {
|
||
ty::ReLateBound(debruijn.shifted_out_to_binder(to_binder), r)
|
||
}
|
||
r => r,
|
||
}
|
||
}
|
||
|
||
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::ReEmpty(_) | 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;
|
||
}
|
||
}
|
||
|
||
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:
|
||
///
|
||
/// ```
|
||
/// 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).unwrap(),
|
||
ty::ReFree(fr) => fr.scope,
|
||
_ => bug!("free_region_binding_scope invoked on inappropriate region: {:?}", self),
|
||
}
|
||
}
|
||
}
|
||
|
||
/// Type utilities
|
||
impl<'tcx> TyS<'tcx> {
|
||
#[inline(always)]
|
||
pub fn kind(&self) -> &TyKind<'tcx> {
|
||
&self.kind
|
||
}
|
||
|
||
#[inline(always)]
|
||
pub fn flags(&self) -> TypeFlags {
|
||
self.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 is_ty_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 {
|
||
match self.kind() {
|
||
RawPtr(TypeAndMut { ty, .. }) | Ref(_, ty, _) => matches!(ty.kind(), Slice(_) | Str),
|
||
_ => 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.mk_mach_uint(ty::UintTy::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) => {
|
||
let variant = def.non_enum_variant();
|
||
let f0_ty = variant.fields[0].ty(tcx, substs);
|
||
|
||
match f0_ty.kind() {
|
||
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_usize(tcx, ParamEnv::empty()) as u64, f0_elem_ty)
|
||
}
|
||
_ => (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(..))
|
||
}
|
||
|
||
#[inline]
|
||
pub fn is_enum(&self) -> bool {
|
||
match self.kind() {
|
||
Adt(adt_def, _) => adt_def.is_enum(),
|
||
_ => false,
|
||
}
|
||
}
|
||
|
||
#[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 is_machine(&self) -> bool {
|
||
matches!(self.kind(), Int(..) | Uint(..) | Float(..))
|
||
}
|
||
|
||
#[inline]
|
||
pub fn has_concrete_skeleton(&self) -> bool {
|
||
!matches!(self.kind(), Param(_) | Infer(_) | Error(_))
|
||
}
|
||
|
||
/// 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, 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(), Opaque(..))
|
||
}
|
||
|
||
#[inline]
|
||
pub fn ty_adt_def(&self) -> Option<&'tcx AdtDef> {
|
||
match self.kind() {
|
||
Adt(adt, _) => Some(adt),
|
||
_ => None,
|
||
}
|
||
}
|
||
|
||
/// Iterates over tuple fields.
|
||
/// Panics when called on anything but a tuple.
|
||
pub fn tuple_fields(&self) -> impl DoubleEndedIterator<Item = Ty<'tcx>> {
|
||
match self.kind() {
|
||
Tuple(substs) => substs.iter().map(|field| field.expect_ty()),
|
||
_ => bug!("tuple_fields called on non-tuple"),
|
||
}
|
||
}
|
||
|
||
/// Get the `i`-th element of a tuple.
|
||
/// Panics when called on anything but a tuple.
|
||
pub fn tuple_element_ty(&self, i: usize) -> Option<Ty<'tcx>> {
|
||
match self.kind() {
|
||
Tuple(substs) => substs.iter().nth(i).map(|field| field.expect_ty()),
|
||
_ => 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() => {
|
||
bug!("discriminant_for_variant called on zero variant enum");
|
||
}
|
||
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(&'tcx 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::Projection(_) | ty::Opaque(..) | ty::Infer(ty::TyVar(_)) => {
|
||
let assoc_items =
|
||
tcx.associated_items(tcx.lang_items().discriminant_kind_trait().unwrap());
|
||
let discriminant_def_id = assoc_items.in_definition_order().next().unwrap().def_id;
|
||
tcx.mk_projection(discriminant_def_id, tcx.mk_substs([self.into()].iter()))
|
||
}
|
||
|
||
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::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.
|
||
pub fn ptr_metadata_ty(&'tcx self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
|
||
// FIXME: should this normalize?
|
||
let tail = tcx.struct_tail_without_normalization(self);
|
||
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::Array(..)
|
||
| ty::Closure(..)
|
||
| ty::Never
|
||
| ty::Error(_)
|
||
| 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,
|
||
|
||
ty::Str | ty::Slice(_) => tcx.types.usize,
|
||
ty::Dynamic(..) => {
|
||
let dyn_metadata = tcx.lang_items().dyn_metadata().unwrap();
|
||
tcx.type_of(dyn_metadata).subst(tcx, &[tail.into()])
|
||
},
|
||
|
||
ty::Projection(_)
|
||
| ty::Param(_)
|
||
| ty::Opaque(..)
|
||
| 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)
|
||
}
|
||
}
|
||
}
|
||
|
||
/// 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
|
||
/// `tcx.closure_kind_ty(closure_kind)`.
|
||
///
|
||
/// 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 `src/librustc_typeck/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::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.expect_ty().is_trivially_sized(tcx)),
|
||
|
||
ty::Adt(def, _substs) => def.sized_constraint(tcx).is_empty(),
|
||
|
||
ty::Projection(_) | ty::Param(_) | ty::Opaque(..) => 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)
|
||
}
|
||
}
|
||
}
|
||
}
|