1939 lines
64 KiB
Rust
1939 lines
64 KiB
Rust
// Copyright 2012-2015 The Rust Project Developers. See the COPYRIGHT
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// file at the top-level directory of this distribution and at
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// http://rust-lang.org/COPYRIGHT.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! This module contains TypeVariants and its major components
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use hir::def_id::DefId;
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use middle::const_val::ConstVal;
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use middle::region;
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use polonius_engine::Atom;
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use rustc_data_structures::indexed_vec::Idx;
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use ty::subst::{Substs, Subst, Kind, UnpackedKind};
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use ty::{self, AdtDef, TypeFlags, Ty, TyCtxt, TypeFoldable};
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use ty::{Slice, TyS};
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use util::captures::Captures;
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use mir::interpret::{PrimVal, MemoryPointer, Value, ConstValue};
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use std::iter;
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use std::cmp::Ordering;
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use rustc_target::spec::abi;
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use syntax::ast::{self, Name};
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use syntax::symbol::{keywords, InternedString};
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use serialize;
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use hir;
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use self::InferTy::*;
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use self::TypeVariants::*;
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#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
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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,
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RustcEncodable, RustcDecodable, Copy)]
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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: BoundRegion,
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}
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#[derive(Clone, PartialEq, PartialOrd, Eq, Ord, Hash,
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RustcEncodable, RustcDecodable, Copy)]
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pub enum BoundRegion {
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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 def-id is needed to distinguish free regions in
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/// the event of shadowing.
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BrNamed(DefId, InternedString),
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/// Fresh bound identifiers created during GLB computations.
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BrFresh(u32),
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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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impl BoundRegion {
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pub fn is_named(&self) -> bool {
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match *self {
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BoundRegion::BrNamed(..) => true,
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_ => false,
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}
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}
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}
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/// NB: If you change this, you'll probably want to change the corresponding
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/// AST structure in libsyntax/ast.rs as well.
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#[derive(Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
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pub enum TypeVariants<'tcx> {
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/// The primitive boolean type. Written as `bool`.
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TyBool,
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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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TyChar,
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/// A primitive signed integer type. For example, `i32`.
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TyInt(ast::IntTy),
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/// A primitive unsigned integer type. For example, `u32`.
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TyUint(ast::UintTy),
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/// A primitive floating-point type. For example, `f64`.
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TyFloat(ast::FloatTy),
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/// Structures, enumerations and unions.
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///
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/// Substs here, possibly against intuition, *may* contain `TyParam`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 `TyAdt` corresponds to an ADT
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/// definition and not a concrete use of it.
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TyAdt(&'tcx AdtDef, &'tcx Substs<'tcx>),
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TyForeign(DefId),
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/// The pointee of a string slice. Written as `str`.
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TyStr,
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/// An array with the given length. Written as `[T; n]`.
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TyArray(Ty<'tcx>, &'tcx ty::Const<'tcx>),
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/// The pointee of an array slice. Written as `[T]`.
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TySlice(Ty<'tcx>),
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/// A raw pointer. Written as `*mut T` or `*const T`
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TyRawPtr(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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TyRef(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.
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TyFnDef(DefId, &'tcx Substs<'tcx>),
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/// A pointer to a function. Written as `fn() -> i32`.
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TyFnPtr(PolyFnSig<'tcx>),
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/// A trait, defined with `trait`.
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TyDynamic(Binder<&'tcx Slice<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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TyClosure(DefId, ClosureSubsts<'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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TyGenerator(DefId, GeneratorSubsts<'tcx>, hir::GeneratorMovability),
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/// A type representin the types stored inside a generator.
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/// This should only appear in GeneratorInteriors.
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TyGeneratorWitness(Binder<&'tcx Slice<Ty<'tcx>>>),
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/// The never type `!`
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TyNever,
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/// A tuple type. For example, `(i32, bool)`.
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TyTuple(&'tcx Slice<Ty<'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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TyProjection(ProjectionTy<'tcx>),
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/// Anonymized (`impl Trait`) type found in a return type.
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/// The DefId comes from the `impl Trait` ast::Ty node, and the
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/// 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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TyAnon(DefId, &'tcx Substs<'tcx>),
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/// A type parameter; for example, `T` in `fn f<T>(x: T) {}
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TyParam(ParamTy),
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/// A type variable used during type-checking.
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TyInfer(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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TyError,
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}
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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, U0...Uk> {
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/// upvar0: U0,
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/// ...
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/// upvark: Uk
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/// }
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///
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/// where:
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///
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/// - 'l0...'li and T0...Tj are the lifetime and type 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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/// - U0...Uk are type parameters representing the types of its upvars
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/// (borrowed, if appropriate; that is, if Ui represents a by-ref upvar,
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/// and the up-var has the type `Foo`, then `Ui = &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, U0> {
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/// data: U0
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/// }
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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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/// as extra type parameters? 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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/// Perhaps surprisingly, `ClosureSubsts` are also used for
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/// generators. In that case, what is written above is only half-true
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/// -- the set of type parameters is similar, but the role of CK and
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/// CS are different. CK represents the "yield type" and CS
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/// represents the "return type" of the generator.
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///
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/// It'd be nice to split this struct into ClosureSubsts and
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/// GeneratorSubsts, I believe. -nmatsakis
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#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
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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 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: &'tcx Substs<'tcx>,
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}
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/// Struct returned by `split()`. Note that these are subslices of the
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/// parent slice and not canonical substs themselves.
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struct SplitClosureSubsts<'tcx> {
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closure_kind_ty: Ty<'tcx>,
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closure_sig_ty: Ty<'tcx>,
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upvar_kinds: &'tcx [Kind<'tcx>],
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}
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impl<'tcx> ClosureSubsts<'tcx> {
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/// Divides the closure substs into their respective
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/// components. Single source of truth with respect to the
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/// ordering.
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fn split(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> SplitClosureSubsts<'tcx> {
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let generics = tcx.generics_of(def_id);
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let parent_len = generics.parent_count;
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SplitClosureSubsts {
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closure_kind_ty: self.substs.type_at(parent_len),
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closure_sig_ty: self.substs.type_at(parent_len + 1),
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upvar_kinds: &self.substs[parent_len + 2..],
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}
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}
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#[inline]
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pub fn upvar_tys(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) ->
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impl Iterator<Item=Ty<'tcx>> + 'tcx
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{
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let SplitClosureSubsts { upvar_kinds, .. } = self.split(def_id, tcx);
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upvar_kinds.iter().map(|t| {
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if let UnpackedKind::Type(ty) = t.unpack() {
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ty
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} else {
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bug!("upvar should be type")
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}
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})
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}
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/// Returns the closure kind for this closure; may return a type
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/// variable during inference. To get the closure kind during
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/// inference, use `infcx.closure_kind(def_id, substs)`.
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pub fn closure_kind_ty(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> Ty<'tcx> {
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self.split(def_id, tcx).closure_kind_ty
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}
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/// Returns the type representing the closure signature for this
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/// closure; may contain type variables during inference. To get
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/// the closure signature during inference, use
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/// `infcx.fn_sig(def_id)`.
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pub fn closure_sig_ty(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> Ty<'tcx> {
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self.split(def_id, tcx).closure_sig_ty
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}
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/// Returns the closure kind for this closure; only usable outside
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/// of an inference context, because in that context we know that
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/// there are no type variables.
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///
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/// If you have an inference context, use `infcx.closure_kind()`.
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pub fn closure_kind(self, def_id: DefId, tcx: TyCtxt<'_, 'tcx, 'tcx>) -> ty::ClosureKind {
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self.split(def_id, tcx).closure_kind_ty.to_opt_closure_kind().unwrap()
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}
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/// Extracts the signature from the closure; only usable outside
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/// of an inference context, because in that context we know that
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/// there are no type variables.
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///
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/// If you have an inference context, use `infcx.closure_sig()`.
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pub fn closure_sig(self, def_id: DefId, tcx: TyCtxt<'_, 'tcx, 'tcx>) -> ty::PolyFnSig<'tcx> {
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match self.closure_sig_ty(def_id, tcx).sty {
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ty::TyFnPtr(sig) => sig,
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ref t => bug!("closure_sig_ty is not a fn-ptr: {:?}", t),
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}
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}
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}
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#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
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pub struct GeneratorSubsts<'tcx> {
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pub substs: &'tcx Substs<'tcx>,
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}
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struct SplitGeneratorSubsts<'tcx> {
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yield_ty: Ty<'tcx>,
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return_ty: Ty<'tcx>,
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witness: Ty<'tcx>,
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upvar_kinds: &'tcx [Kind<'tcx>],
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}
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impl<'tcx> GeneratorSubsts<'tcx> {
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fn split(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> SplitGeneratorSubsts<'tcx> {
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let generics = tcx.generics_of(def_id);
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let parent_len = generics.parent_count;
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SplitGeneratorSubsts {
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yield_ty: self.substs.type_at(parent_len),
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return_ty: self.substs.type_at(parent_len + 1),
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witness: self.substs.type_at(parent_len + 2),
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upvar_kinds: &self.substs[parent_len + 3..],
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}
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}
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/// This describes the types that can be contained in a generator.
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/// It will be a type variable initially and unified in the last stages of typeck of a body.
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/// It contains a tuple of all the types that could end up on a generator frame.
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/// The state transformation MIR pass may only produce layouts which mention types
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/// in this tuple. Upvars are not counted here.
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pub fn witness(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> Ty<'tcx> {
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self.split(def_id, tcx).witness
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}
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#[inline]
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pub fn upvar_tys(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) ->
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impl Iterator<Item=Ty<'tcx>> + 'tcx
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{
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let SplitGeneratorSubsts { upvar_kinds, .. } = self.split(def_id, tcx);
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upvar_kinds.iter().map(|t| {
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if let UnpackedKind::Type(ty) = t.unpack() {
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ty
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} else {
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bug!("upvar should be type")
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}
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})
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}
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/// Returns the type representing the yield type of the generator.
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pub fn yield_ty(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> Ty<'tcx> {
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self.split(def_id, tcx).yield_ty
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}
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/// Returns the type representing the return type of the generator.
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pub fn return_ty(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> Ty<'tcx> {
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self.split(def_id, tcx).return_ty
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}
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/// Return the "generator signature", which consists of its yield
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/// and return types.
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///
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/// NB. Some bits of the code prefers to see this wrapped in a
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/// binder, but it never contains bound regions. Probably this
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/// function should be removed.
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pub fn poly_sig(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> PolyGenSig<'tcx> {
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ty::Binder::dummy(self.sig(def_id, tcx))
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}
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/// Return the "generator signature", which consists of its yield
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/// and return types.
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pub fn sig(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) -> GenSig<'tcx> {
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ty::GenSig {
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yield_ty: self.yield_ty(def_id, tcx),
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return_ty: self.return_ty(def_id, tcx),
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}
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}
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}
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impl<'a, 'gcx, 'tcx> GeneratorSubsts<'tcx> {
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/// This returns the types of the MIR locals which had to be stored across suspension points.
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/// It is calculated in rustc_mir::transform::generator::StateTransform.
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/// All the types here must be in the tuple in GeneratorInterior.
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pub fn state_tys(
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self,
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def_id: DefId,
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tcx: TyCtxt<'a, 'gcx, 'tcx>,
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) -> impl Iterator<Item=Ty<'tcx>> + Captures<'gcx> + 'a {
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let state = tcx.generator_layout(def_id).fields.iter();
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state.map(move |d| d.ty.subst(tcx, self.substs))
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}
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/// This is the types of the fields of a generate which
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/// is available before the generator transformation.
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/// It includes the upvars and the state discriminant which is u32.
|
|
pub fn pre_transforms_tys(self, def_id: DefId, tcx: TyCtxt<'a, 'gcx, 'tcx>) ->
|
|
impl Iterator<Item=Ty<'tcx>> + 'a
|
|
{
|
|
self.upvar_tys(def_id, tcx).chain(iter::once(tcx.types.u32))
|
|
}
|
|
|
|
/// This is the types of all the fields stored in a generator.
|
|
/// It includes the upvars, state types and the state discriminant which is u32.
|
|
pub fn field_tys(self, def_id: DefId, tcx: TyCtxt<'a, 'gcx, 'tcx>) ->
|
|
impl Iterator<Item=Ty<'tcx>> + Captures<'gcx> + 'a
|
|
{
|
|
self.pre_transforms_tys(def_id, tcx).chain(self.state_tys(def_id, tcx))
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Copy, Clone)]
|
|
pub enum UpvarSubsts<'tcx> {
|
|
Closure(ClosureSubsts<'tcx>),
|
|
Generator(GeneratorSubsts<'tcx>),
|
|
}
|
|
|
|
impl<'tcx> UpvarSubsts<'tcx> {
|
|
#[inline]
|
|
pub fn upvar_tys(self, def_id: DefId, tcx: TyCtxt<'_, '_, '_>) ->
|
|
impl Iterator<Item=Ty<'tcx>> + 'tcx
|
|
{
|
|
let upvar_kinds = match self {
|
|
UpvarSubsts::Closure(substs) => substs.split(def_id, tcx).upvar_kinds,
|
|
UpvarSubsts::Generator(substs) => substs.split(def_id, tcx).upvar_kinds,
|
|
};
|
|
upvar_kinds.iter().map(|t| {
|
|
if let UnpackedKind::Type(ty) = t.unpack() {
|
|
ty
|
|
} else {
|
|
bug!("upvar should be type")
|
|
}
|
|
})
|
|
}
|
|
}
|
|
|
|
#[derive(Debug, Copy, Clone, PartialEq, PartialOrd, Ord, Eq, Hash, RustcEncodable, RustcDecodable)]
|
|
pub enum ExistentialPredicate<'tcx> {
|
|
/// e.g. Iterator
|
|
Trait(ExistentialTraitRef<'tcx>),
|
|
/// e.g. Iterator::Item = T
|
|
Projection(ExistentialProjection<'tcx>),
|
|
/// e.g. Send
|
|
AutoTrait(DefId),
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> ExistentialPredicate<'tcx> {
|
|
pub fn cmp(&self, tcx: TyCtxt<'a, 'gcx, '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<'a, 'gcx, 'tcx> Binder<ExistentialPredicate<'tcx>> {
|
|
pub fn with_self_ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, self_ty: Ty<'tcx>)
|
|
-> ty::Predicate<'tcx> {
|
|
use ty::ToPredicate;
|
|
match *self.skip_binder() {
|
|
ExistentialPredicate::Trait(tr) => Binder(tr).with_self_ty(tcx, self_ty).to_predicate(),
|
|
ExistentialPredicate::Projection(p) =>
|
|
ty::Predicate::Projection(Binder(p.with_self_ty(tcx, self_ty))),
|
|
ExistentialPredicate::AutoTrait(did) => {
|
|
let trait_ref = Binder(ty::TraitRef {
|
|
def_id: did,
|
|
substs: tcx.mk_substs_trait(self_ty, &[]),
|
|
});
|
|
trait_ref.to_predicate()
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Slice<ExistentialPredicate<'tcx>> {}
|
|
|
|
impl<'tcx> Slice<ExistentialPredicate<'tcx>> {
|
|
pub fn principal(&self) -> Option<ExistentialTraitRef<'tcx>> {
|
|
match self.get(0) {
|
|
Some(&ExistentialPredicate::Trait(tr)) => Some(tr),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn projection_bounds<'a>(&'a self) ->
|
|
impl Iterator<Item=ExistentialProjection<'tcx>> + 'a {
|
|
self.iter().filter_map(|predicate| {
|
|
match *predicate {
|
|
ExistentialPredicate::Projection(p) => Some(p),
|
|
_ => None,
|
|
}
|
|
})
|
|
}
|
|
|
|
#[inline]
|
|
pub fn auto_traits<'a>(&'a self) -> impl Iterator<Item=DefId> + 'a {
|
|
self.iter().filter_map(|predicate| {
|
|
match *predicate {
|
|
ExistentialPredicate::AutoTrait(d) => Some(d),
|
|
_ => None
|
|
}
|
|
})
|
|
}
|
|
}
|
|
|
|
impl<'tcx> Binder<&'tcx Slice<ExistentialPredicate<'tcx>>> {
|
|
pub fn principal(&self) -> Option<PolyExistentialTraitRef<'tcx>> {
|
|
self.skip_binder().principal().map(Binder::bind)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn projection_bounds<'a>(&'a self) ->
|
|
impl Iterator<Item=PolyExistentialProjection<'tcx>> + 'a {
|
|
self.skip_binder().projection_bounds().map(Binder::bind)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn auto_traits<'a>(&'a self) -> impl Iterator<Item=DefId> + 'a {
|
|
self.skip_binder().auto_traits()
|
|
}
|
|
|
|
pub fn iter<'a>(&'a self)
|
|
-> impl DoubleEndedIterator<Item=Binder<ExistentialPredicate<'tcx>>> + 'tcx {
|
|
self.skip_binder().iter().cloned().map(Binder::bind)
|
|
}
|
|
}
|
|
|
|
/// 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 def-id is the
|
|
/// def-id 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.
|
|
///
|
|
/// Note that a `TraitRef` introduces a level of region binding, to
|
|
/// account for higher-ranked trait bounds like `T : for<'a> Foo<&'a
|
|
/// U>` or higher-ranked object types.
|
|
#[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
|
|
pub struct TraitRef<'tcx> {
|
|
pub def_id: DefId,
|
|
pub substs: &'tcx Substs<'tcx>,
|
|
}
|
|
|
|
impl<'tcx> TraitRef<'tcx> {
|
|
pub fn new(def_id: DefId, substs: &'tcx Substs<'tcx>) -> TraitRef<'tcx> {
|
|
TraitRef { def_id: def_id, substs: substs }
|
|
}
|
|
|
|
pub fn self_ty(&self) -> Ty<'tcx> {
|
|
self.substs.type_at(0)
|
|
}
|
|
|
|
pub fn input_types<'a>(&'a self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'a {
|
|
// Select only the "input types" from a trait-reference. For
|
|
// now this is all the types that appear in the
|
|
// trait-reference, but it should eventually exclude
|
|
// associated types.
|
|
self.substs.types()
|
|
}
|
|
|
|
pub fn from_method(tcx: TyCtxt<'_, '_, 'tcx>,
|
|
trait_id: DefId,
|
|
substs: &Substs<'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) -> Ty<'tcx> {
|
|
self.skip_binder().self_ty()
|
|
}
|
|
|
|
pub fn def_id(&self) -> DefId {
|
|
self.skip_binder().def_id
|
|
}
|
|
|
|
pub fn to_poly_trait_predicate(&self) -> ty::PolyTraitPredicate<'tcx> {
|
|
// Note that we preserve binding levels
|
|
Binder(ty::TraitPredicate { trait_ref: self.skip_binder().clone() })
|
|
}
|
|
}
|
|
|
|
/// 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, RustcEncodable, RustcDecodable)]
|
|
pub struct ExistentialTraitRef<'tcx> {
|
|
pub def_id: DefId,
|
|
pub substs: &'tcx Substs<'tcx>,
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> ExistentialTraitRef<'tcx> {
|
|
pub fn input_types<'b>(&'b self) -> impl DoubleEndedIterator<Item=Ty<'tcx>> + 'b {
|
|
// Select only the "input types" from a trait-reference. For
|
|
// now this is all the types that appear in the
|
|
// trait-reference, but it should eventually exclude
|
|
// associated types.
|
|
self.substs.types()
|
|
}
|
|
|
|
pub fn erase_self_ty(tcx: TyCtxt<'a, 'gcx, '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 skolemized type.
|
|
pub fn with_self_ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>, self_ty: Ty<'tcx>)
|
|
-> ty::TraitRef<'tcx> {
|
|
// otherwise the escaping regions would be captured by the binder
|
|
assert!(!self_ty.has_escaping_regions());
|
|
|
|
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 skolemized 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. 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 skolemize, instantiate,
|
|
/// erase, or otherwise "discharge" these bound regions, we change the
|
|
/// type from `Binder<T>` to just `T` (see
|
|
/// e.g. `liberate_late_bound_regions`).
|
|
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
|
|
pub struct Binder<T>(T);
|
|
|
|
impl<T> Binder<T> {
|
|
/// Wraps `value` in a binder, asserting that `value` does not
|
|
/// contain any bound regions 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>
|
|
{
|
|
assert!(!value.has_escaping_regions());
|
|
Binder(value)
|
|
}
|
|
|
|
/// Wraps `value` in a binder, binding late-bound regions (if any).
|
|
pub fn bind<'tcx>(value: T) -> Binder<T>
|
|
{
|
|
Binder(value)
|
|
}
|
|
|
|
/// Skips the binder and returns the "bound" value. This is a
|
|
/// risky thing to do because it's easy to get confused about
|
|
/// debruijn indices and the like. It is usually better to
|
|
/// discharge the binder using `no_late_bound_regions` 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 regions, 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 def-id 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))
|
|
}
|
|
|
|
/// Unwraps and returns the value within, but only if it contains
|
|
/// no bound regions 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 regions 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_late_bound_regions<'tcx>(self) -> Option<T>
|
|
where T : TypeFoldable<'tcx>
|
|
{
|
|
if self.skip_binder().has_escaping_regions() {
|
|
None
|
|
} else {
|
|
Some(self.skip_binder().clone())
|
|
}
|
|
}
|
|
|
|
/// Given two things that have the same binder level,
|
|
/// and an operation that wraps on their contents, execute the operation
|
|
/// and then wrap 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))
|
|
}
|
|
|
|
/// Split 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))
|
|
}
|
|
}
|
|
|
|
/// 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, RustcEncodable, RustcDecodable)]
|
|
pub struct ProjectionTy<'tcx> {
|
|
/// The parameters of the associated item.
|
|
pub substs: &'tcx Substs<'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<'a, 'tcx> ProjectionTy<'tcx> {
|
|
/// Construct a ProjectionTy by searching the trait from trait_ref for the
|
|
/// associated item named item_name.
|
|
pub fn from_ref_and_name(
|
|
tcx: TyCtxt, trait_ref: ty::TraitRef<'tcx>, item_name: Name
|
|
) -> ProjectionTy<'tcx> {
|
|
let item_def_id = tcx.associated_items(trait_ref.def_id).find(|item| {
|
|
item.kind == ty::AssociatedKind::Type &&
|
|
tcx.hygienic_eq(item_name, item.name, trait_ref.def_id)
|
|
}).unwrap().def_id;
|
|
|
|
ProjectionTy {
|
|
substs: trait_ref.substs,
|
|
item_def_id,
|
|
}
|
|
}
|
|
|
|
/// 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.
|
|
pub fn trait_ref(&self, tcx: TyCtxt) -> ty::TraitRef<'tcx> {
|
|
let def_id = tcx.associated_item(self.item_def_id).container.id();
|
|
ty::TraitRef {
|
|
def_id,
|
|
substs: self.substs,
|
|
}
|
|
}
|
|
|
|
pub fn self_ty(&self) -> Ty<'tcx> {
|
|
self.substs.type_at(0)
|
|
}
|
|
}
|
|
|
|
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable)]
|
|
pub struct GenSig<'tcx> {
|
|
pub yield_ty: Ty<'tcx>,
|
|
pub return_ty: Ty<'tcx>,
|
|
}
|
|
|
|
pub type PolyGenSig<'tcx> = Binder<GenSig<'tcx>>;
|
|
|
|
impl<'tcx> PolyGenSig<'tcx> {
|
|
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 I 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.
|
|
/// - `variadic` indicates whether this is a variadic function. (only true for foreign fns)
|
|
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
|
|
pub struct FnSig<'tcx> {
|
|
pub inputs_and_output: &'tcx Slice<Ty<'tcx>>,
|
|
pub 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]
|
|
}
|
|
}
|
|
|
|
pub type PolyFnSig<'tcx> = Binder<FnSig<'tcx>>;
|
|
|
|
impl<'tcx> PolyFnSig<'tcx> {
|
|
pub fn inputs(&self) -> Binder<&'tcx [Ty<'tcx>]> {
|
|
self.map_bound_ref(|fn_sig| fn_sig.inputs())
|
|
}
|
|
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 Slice<Ty<'tcx>>> {
|
|
self.map_bound_ref(|fn_sig| fn_sig.inputs_and_output)
|
|
}
|
|
pub fn output(&self) -> ty::Binder<Ty<'tcx>> {
|
|
self.map_bound_ref(|fn_sig| fn_sig.output().clone())
|
|
}
|
|
pub fn variadic(&self) -> bool {
|
|
self.skip_binder().variadic
|
|
}
|
|
pub fn unsafety(&self) -> hir::Unsafety {
|
|
self.skip_binder().unsafety
|
|
}
|
|
pub fn abi(&self) -> abi::Abi {
|
|
self.skip_binder().abi
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
|
|
pub struct ParamTy {
|
|
pub idx: u32,
|
|
pub name: InternedString,
|
|
}
|
|
|
|
impl<'a, 'gcx, 'tcx> ParamTy {
|
|
pub fn new(index: u32, name: InternedString) -> ParamTy {
|
|
ParamTy { idx: index, name: name }
|
|
}
|
|
|
|
pub fn for_self() -> ParamTy {
|
|
ParamTy::new(0, keywords::SelfType.name().as_interned_str())
|
|
}
|
|
|
|
pub fn for_def(def: &ty::GenericParamDef) -> ParamTy {
|
|
ParamTy::new(def.index, def.name)
|
|
}
|
|
|
|
pub fn to_ty(self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
|
|
tcx.mk_ty_param(self.idx, self.name)
|
|
}
|
|
|
|
pub fn is_self(&self) -> bool {
|
|
// FIXME(#50125): Ignoring `Self` with `idx != 0` might lead to weird behavior elsewhere,
|
|
// but this should only be possible when using `-Z continue-parse-after-error` like
|
|
// `compile-fail/issue-36638.rs`.
|
|
if self.name == keywords::SelfType.name().as_str() && self.idx == 0 {
|
|
true
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
}
|
|
|
|
/// A [De Bruijn index][dbi] is a standard means of representing
|
|
/// regions (and perhaps later types) in a higher-ranked setting. In
|
|
/// particular, imagine a type like this:
|
|
///
|
|
/// for<'a> fn(for<'b> fn(&'b isize, &'a isize), &'a char)
|
|
/// ^ ^ | | |
|
|
/// | | | | |
|
|
/// | +------------+ 1 | |
|
|
/// | | |
|
|
/// +--------------------------------+ 2 |
|
|
/// | |
|
|
/// +------------------------------------------+ 1
|
|
///
|
|
/// In this type, there are two binders (the outer fn and the inner
|
|
/// fn). We need to be able to determine, for any given region, which
|
|
/// fn type it is bound by, the inner or the outer one. There are
|
|
/// various ways you can do this, but a De Bruijn index is one of the
|
|
/// more convenient and has some nice properties. The basic idea is to
|
|
/// count the number of binders, inside out. Some examples should help
|
|
/// clarify what I mean.
|
|
///
|
|
/// Let's start with the reference type `&'b isize` that is the first
|
|
/// argument to the inner function. This region `'b` is assigned a De
|
|
/// Bruijn index of 1, meaning "the innermost binder" (in this case, a
|
|
/// fn). The region `'a` that appears in the second argument type (`&'a
|
|
/// isize`) would then be assigned a De Bruijn index of 2, meaning "the
|
|
/// second-innermost binder". (These indices are written on the arrays
|
|
/// in the diagram).
|
|
///
|
|
/// What is interesting is that De Bruijn index attached to a particular
|
|
/// variable will vary depending on where it appears. For example,
|
|
/// the final type `&'a char` also refers to the region `'a` declared on
|
|
/// the outermost fn. But this time, this reference is not nested within
|
|
/// any other binders (i.e., it is not an argument to the inner fn, but
|
|
/// rather the outer one). Therefore, in this case, it is assigned a
|
|
/// De Bruijn index of 1, because the innermost binder in that location
|
|
/// is the outer fn.
|
|
///
|
|
/// [dbi]: http://en.wikipedia.org/wiki/De_Bruijn_index
|
|
#[derive(Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Debug, Copy, PartialOrd, Ord)]
|
|
pub struct DebruijnIndex {
|
|
/// We maintain the invariant that this is never 0. So 1 indicates
|
|
/// the innermost binder. To ensure this, create with `DebruijnIndex::new`.
|
|
pub depth: u32,
|
|
}
|
|
|
|
pub type Region<'tcx> = &'tcx RegionKind;
|
|
|
|
/// Representation of regions.
|
|
///
|
|
/// Unlike types, most region variants are "fictitious", not concrete,
|
|
/// regions. Among these, `ReStatic`, `ReEmpty` and `ReScope` are the only
|
|
/// ones representing concrete regions.
|
|
///
|
|
/// ## Bound Regions
|
|
///
|
|
/// These are regions that are stored behind a binder and must be substituted
|
|
/// with some concrete region before being used. There are 2 kind of
|
|
/// bound regions: early-bound, which are bound in an item's Generics,
|
|
/// and are substituted by a Substs, 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 TyParam-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 skolemized regions, free regions,
|
|
/// or region variables).
|
|
///
|
|
/// ## Skolemized 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.
|
|
///
|
|
/// The process of doing that is called "skolemization". The bound regions
|
|
/// are replaced by skolemized markers, which don't satisfy any relation
|
|
/// not explicitly provided.
|
|
///
|
|
/// There are 2 kinds of skolemized regions in rustc: `ReFree` and
|
|
/// `ReSkolemized`. 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`.
|
|
/// `ReSkolemized` is designed for this purpose. In these contexts,
|
|
/// there's also the risk that some inference variable laying around will
|
|
/// get unified with your skolemized region: if you want to check whether
|
|
/// `for<'a> Foo<'_>: 'a`, and you substitute your bound region `'a`
|
|
/// with a skolemized region `'%a`, the variable `'_` would just be
|
|
/// instantiated to the skolemized region `'%a`, which is wrong because
|
|
/// the inference variable is supposed to satisfy the relation
|
|
/// *for every value of the skolemized region*. To ensure that doesn't
|
|
/// happen, you can use `leak_check`. This is more clearly explained
|
|
/// by the [rustc 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 guide]: https://rust-lang-nursery.github.io/rustc-guide/trait-hrtb.html
|
|
#[derive(Clone, PartialEq, Eq, Hash, Copy, RustcEncodable, RustcDecodable, 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(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),
|
|
|
|
/// A concrete region naming some statically determined scope
|
|
/// (e.g. an expression or sequence of statements) within the
|
|
/// current function.
|
|
ReScope(region::Scope),
|
|
|
|
/// Static data that has an "infinite" lifetime. Top in the region lattice.
|
|
ReStatic,
|
|
|
|
/// A region variable. Should not exist after typeck.
|
|
ReVar(RegionVid),
|
|
|
|
/// A skolemized region - basically the higher-ranked version of ReFree.
|
|
/// Should not exist after typeck.
|
|
ReSkolemized(ty::UniverseIndex, BoundRegion),
|
|
|
|
/// Empty lifetime is for data that is never accessed.
|
|
/// Bottom in the region lattice. We treat ReEmpty somewhat
|
|
/// specially; at least right now, we do not generate instances of
|
|
/// it during the GLB computations, but rather
|
|
/// generate an error instead. This is to improve error messages.
|
|
/// The only way to get an instance of ReEmpty is to have a region
|
|
/// variable with no constraints.
|
|
ReEmpty,
|
|
|
|
/// Erased region, used by trait selection, in MIR and during codegen.
|
|
ReErased,
|
|
|
|
/// These are regions bound in the "defining type" for a
|
|
/// closure. They are used ONLY as part of the
|
|
/// `ClosureRegionRequirements` that are produced by MIR borrowck.
|
|
/// See `ClosureRegionRequirements` for more details.
|
|
ReClosureBound(RegionVid),
|
|
|
|
/// Canonicalized region, used only when preparing a trait query.
|
|
ReCanonical(CanonicalVar),
|
|
}
|
|
|
|
impl<'tcx> serialize::UseSpecializedDecodable for Region<'tcx> {}
|
|
|
|
#[derive(Copy, Clone, PartialEq, Eq, Hash, RustcEncodable, RustcDecodable, Debug, PartialOrd, Ord)]
|
|
pub struct EarlyBoundRegion {
|
|
pub def_id: DefId,
|
|
pub index: u32,
|
|
pub name: InternedString,
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
|
|
pub struct TyVid {
|
|
pub index: u32,
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
|
|
pub struct IntVid {
|
|
pub index: u32,
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
|
|
pub struct FloatVid {
|
|
pub index: u32,
|
|
}
|
|
|
|
newtype_index!(RegionVid
|
|
{
|
|
pub idx
|
|
DEBUG_FORMAT = custom,
|
|
});
|
|
|
|
impl Atom for RegionVid {
|
|
fn index(self) -> usize {
|
|
Idx::index(self)
|
|
}
|
|
}
|
|
|
|
impl From<usize> for RegionVid {
|
|
fn from(i: usize) -> RegionVid {
|
|
RegionVid::new(i)
|
|
}
|
|
}
|
|
|
|
impl From<RegionVid> for usize {
|
|
fn from(vid: RegionVid) -> usize {
|
|
Idx::index(vid)
|
|
}
|
|
}
|
|
|
|
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, RustcEncodable, RustcDecodable)]
|
|
pub enum InferTy {
|
|
TyVar(TyVid),
|
|
IntVar(IntVid),
|
|
FloatVar(FloatVid),
|
|
|
|
/// A `FreshTy` is one that is generated as a replacement for an
|
|
/// unbound type variable. This is convenient for caching etc. See
|
|
/// `infer::freshen` for more details.
|
|
FreshTy(u32),
|
|
FreshIntTy(u32),
|
|
FreshFloatTy(u32),
|
|
|
|
/// Canonicalized type variable, used only when preparing a trait query.
|
|
CanonicalTy(CanonicalVar),
|
|
}
|
|
|
|
newtype_index!(CanonicalVar);
|
|
|
|
/// A `ProjectionPredicate` for an `ExistentialTraitRef`.
|
|
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, RustcEncodable, RustcDecodable)]
|
|
pub struct ExistentialProjection<'tcx> {
|
|
pub item_def_id: DefId,
|
|
pub substs: &'tcx Substs<'tcx>,
|
|
pub ty: Ty<'tcx>,
|
|
}
|
|
|
|
pub type PolyExistentialProjection<'tcx> = Binder<ExistentialProjection<'tcx>>;
|
|
|
|
impl<'a, 'tcx, 'gcx> 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) -> ty::ExistentialTraitRef<'tcx> {
|
|
let def_id = tcx.associated_item(self.item_def_id).container.id();
|
|
ty::ExistentialTraitRef{
|
|
def_id,
|
|
substs: self.substs,
|
|
}
|
|
}
|
|
|
|
pub fn with_self_ty(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>,
|
|
self_ty: Ty<'tcx>)
|
|
-> ty::ProjectionPredicate<'tcx>
|
|
{
|
|
// otherwise the escaping regions would be captured by the binders
|
|
assert!(!self_ty.has_escaping_regions());
|
|
|
|
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,
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'a, 'tcx, 'gcx> PolyExistentialProjection<'tcx> {
|
|
pub fn with_self_ty(&self, tcx: TyCtxt<'a, 'gcx, '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 {
|
|
return self.skip_binder().item_def_id;
|
|
}
|
|
}
|
|
|
|
impl DebruijnIndex {
|
|
pub fn new(depth: u32) -> DebruijnIndex {
|
|
assert!(depth > 0);
|
|
DebruijnIndex { depth: depth }
|
|
}
|
|
|
|
pub fn shifted(&self, amount: u32) -> DebruijnIndex {
|
|
DebruijnIndex { depth: self.depth + amount }
|
|
}
|
|
}
|
|
|
|
/// Region utilities
|
|
impl RegionKind {
|
|
pub fn is_late_bound(&self) -> bool {
|
|
match *self {
|
|
ty::ReLateBound(..) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn escapes_depth(&self, depth: u32) -> bool {
|
|
match *self {
|
|
ty::ReLateBound(debruijn, _) => debruijn.depth > depth,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
/// Returns the depth of `self` from the (1-based) binding level `depth`
|
|
pub fn from_depth(&self, depth: u32) -> RegionKind {
|
|
match *self {
|
|
ty::ReLateBound(debruijn, r) => ty::ReLateBound(DebruijnIndex {
|
|
depth: debruijn.depth - (depth - 1)
|
|
}, r),
|
|
r => r
|
|
}
|
|
}
|
|
|
|
pub fn keep_in_local_tcx(&self) -> bool {
|
|
if let ty::ReVar(..) = self {
|
|
true
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
pub fn type_flags(&self) -> TypeFlags {
|
|
let mut flags = TypeFlags::empty();
|
|
|
|
if self.keep_in_local_tcx() {
|
|
flags = flags | TypeFlags::KEEP_IN_LOCAL_TCX;
|
|
}
|
|
|
|
match *self {
|
|
ty::ReVar(..) => {
|
|
flags = flags | TypeFlags::HAS_FREE_REGIONS;
|
|
flags = flags | TypeFlags::HAS_RE_INFER;
|
|
}
|
|
ty::ReSkolemized(..) => {
|
|
flags = flags | TypeFlags::HAS_FREE_REGIONS;
|
|
flags = flags | TypeFlags::HAS_RE_SKOL;
|
|
}
|
|
ty::ReLateBound(..) => {
|
|
flags = flags | TypeFlags::HAS_RE_LATE_BOUND;
|
|
}
|
|
ty::ReEarlyBound(..) => {
|
|
flags = flags | TypeFlags::HAS_FREE_REGIONS;
|
|
flags = flags | TypeFlags::HAS_RE_EARLY_BOUND;
|
|
}
|
|
ty::ReEmpty |
|
|
ty::ReStatic |
|
|
ty::ReFree { .. } |
|
|
ty::ReScope { .. } => {
|
|
flags = flags | TypeFlags::HAS_FREE_REGIONS;
|
|
}
|
|
ty::ReErased => {
|
|
}
|
|
ty::ReCanonical(..) => {
|
|
flags = flags | TypeFlags::HAS_FREE_REGIONS;
|
|
flags = flags | TypeFlags::HAS_CANONICAL_VARS;
|
|
}
|
|
ty::ReClosureBound(..) => {
|
|
flags = flags | TypeFlags::HAS_FREE_REGIONS;
|
|
}
|
|
}
|
|
|
|
match *self {
|
|
ty::ReStatic | ty::ReEmpty | ty::ReErased | ty::ReLateBound(..) => (),
|
|
_ => flags = flags | TypeFlags::HAS_FREE_LOCAL_NAMES,
|
|
}
|
|
|
|
debug!("type_flags({:?}) = {:?}", self, flags);
|
|
|
|
flags
|
|
}
|
|
|
|
/// Given an early-bound or free region, returns the def-id 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 def-id
|
|
/// of the impl, and for all the other highlighted regions, it
|
|
/// would return the def-id of the function. In other cases (not shown), this
|
|
/// function might return the def-id of a closure.
|
|
pub fn free_region_binding_scope(&self, tcx: TyCtxt<'_, '_, '_>) -> DefId {
|
|
match self {
|
|
ty::ReEarlyBound(br) => {
|
|
tcx.parent_def_id(br.def_id).unwrap()
|
|
}
|
|
ty::ReFree(fr) => fr.scope,
|
|
_ => bug!("free_region_binding_scope invoked on inappropriate region: {:?}", self),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Type utilities
|
|
impl<'a, 'gcx, 'tcx> TyS<'tcx> {
|
|
pub fn is_nil(&self) -> bool {
|
|
match self.sty {
|
|
TyTuple(ref tys) => tys.is_empty(),
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_never(&self) -> bool {
|
|
match self.sty {
|
|
TyNever => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_primitive(&self) -> bool {
|
|
match self.sty {
|
|
TyBool | TyChar | TyInt(_) | TyUint(_) | TyFloat(_) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_ty_var(&self) -> bool {
|
|
match self.sty {
|
|
TyInfer(TyVar(_)) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_ty_infer(&self) -> bool {
|
|
match self.sty {
|
|
TyInfer(_) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_phantom_data(&self) -> bool {
|
|
if let TyAdt(def, _) = self.sty {
|
|
def.is_phantom_data()
|
|
} else {
|
|
false
|
|
}
|
|
}
|
|
|
|
pub fn is_bool(&self) -> bool { self.sty == TyBool }
|
|
|
|
pub fn is_param(&self, index: u32) -> bool {
|
|
match self.sty {
|
|
ty::TyParam(ref data) => data.idx == index,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_self(&self) -> bool {
|
|
match self.sty {
|
|
TyParam(ref p) => p.is_self(),
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_slice(&self) -> bool {
|
|
match self.sty {
|
|
TyRawPtr(TypeAndMut { ty, .. }) | TyRef(_, ty, _) => match ty.sty {
|
|
TySlice(_) | TyStr => true,
|
|
_ => false,
|
|
},
|
|
_ => false
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn is_simd(&self) -> bool {
|
|
match self.sty {
|
|
TyAdt(def, _) => def.repr.simd(),
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn sequence_element_type(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
|
|
match self.sty {
|
|
TyArray(ty, _) | TySlice(ty) => ty,
|
|
TyStr => tcx.mk_mach_uint(ast::UintTy::U8),
|
|
_ => bug!("sequence_element_type called on non-sequence value: {}", self),
|
|
}
|
|
}
|
|
|
|
pub fn simd_type(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> Ty<'tcx> {
|
|
match self.sty {
|
|
TyAdt(def, substs) => {
|
|
def.non_enum_variant().fields[0].ty(tcx, substs)
|
|
}
|
|
_ => bug!("simd_type called on invalid type")
|
|
}
|
|
}
|
|
|
|
pub fn simd_size(&self, _cx: TyCtxt) -> usize {
|
|
match self.sty {
|
|
TyAdt(def, _) => def.non_enum_variant().fields.len(),
|
|
_ => bug!("simd_size called on invalid type")
|
|
}
|
|
}
|
|
|
|
pub fn is_region_ptr(&self) -> bool {
|
|
match self.sty {
|
|
TyRef(..) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_mutable_pointer(&self) -> bool {
|
|
match self.sty {
|
|
TyRawPtr(TypeAndMut { mutbl: hir::Mutability::MutMutable, .. }) |
|
|
TyRef(_, _, hir::Mutability::MutMutable) => true,
|
|
_ => false
|
|
}
|
|
}
|
|
|
|
pub fn is_unsafe_ptr(&self) -> bool {
|
|
match self.sty {
|
|
TyRawPtr(_) => return true,
|
|
_ => return false,
|
|
}
|
|
}
|
|
|
|
pub fn is_box(&self) -> bool {
|
|
match self.sty {
|
|
TyAdt(def, _) => def.is_box(),
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
/// panics if called on any type other than `Box<T>`
|
|
pub fn boxed_ty(&self) -> Ty<'tcx> {
|
|
match self.sty {
|
|
TyAdt(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 TyRawPtr is scalar because it represents a non-managed pointer, so its
|
|
/// contents are abstract to rustc.)
|
|
pub fn is_scalar(&self) -> bool {
|
|
match self.sty {
|
|
TyBool | TyChar | TyInt(_) | TyFloat(_) | TyUint(_) |
|
|
TyInfer(IntVar(_)) | TyInfer(FloatVar(_)) |
|
|
TyFnDef(..) | TyFnPtr(_) | TyRawPtr(_) => true,
|
|
_ => false
|
|
}
|
|
}
|
|
|
|
/// Returns true if this type is a floating point type and false otherwise.
|
|
pub fn is_floating_point(&self) -> bool {
|
|
match self.sty {
|
|
TyFloat(_) |
|
|
TyInfer(FloatVar(_)) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_trait(&self) -> bool {
|
|
match self.sty {
|
|
TyDynamic(..) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_enum(&self) -> bool {
|
|
match self.sty {
|
|
TyAdt(adt_def, _) => {
|
|
adt_def.is_enum()
|
|
}
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_closure(&self) -> bool {
|
|
match self.sty {
|
|
TyClosure(..) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_generator(&self) -> bool {
|
|
match self.sty {
|
|
TyGenerator(..) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_integral(&self) -> bool {
|
|
match self.sty {
|
|
TyInfer(IntVar(_)) | TyInt(_) | TyUint(_) => true,
|
|
_ => false
|
|
}
|
|
}
|
|
|
|
pub fn is_fresh_ty(&self) -> bool {
|
|
match self.sty {
|
|
TyInfer(FreshTy(_)) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_fresh(&self) -> bool {
|
|
match self.sty {
|
|
TyInfer(FreshTy(_)) => true,
|
|
TyInfer(FreshIntTy(_)) => true,
|
|
TyInfer(FreshFloatTy(_)) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_char(&self) -> bool {
|
|
match self.sty {
|
|
TyChar => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_fp(&self) -> bool {
|
|
match self.sty {
|
|
TyInfer(FloatVar(_)) | TyFloat(_) => true,
|
|
_ => false
|
|
}
|
|
}
|
|
|
|
pub fn is_numeric(&self) -> bool {
|
|
self.is_integral() || self.is_fp()
|
|
}
|
|
|
|
pub fn is_signed(&self) -> bool {
|
|
match self.sty {
|
|
TyInt(_) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn is_machine(&self) -> bool {
|
|
match self.sty {
|
|
TyInt(ast::IntTy::Isize) | TyUint(ast::UintTy::Usize) => false,
|
|
TyInt(..) | TyUint(..) | TyFloat(..) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn has_concrete_skeleton(&self) -> bool {
|
|
match self.sty {
|
|
TyParam(_) | TyInfer(_) | TyError => false,
|
|
_ => true,
|
|
}
|
|
}
|
|
|
|
/// 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.sty {
|
|
TyAdt(def, _) if def.is_box() => {
|
|
Some(TypeAndMut {
|
|
ty: self.boxed_ty(),
|
|
mutbl: hir::MutImmutable,
|
|
})
|
|
},
|
|
TyRef(_, ty, mutbl) => Some(TypeAndMut { ty, mutbl }),
|
|
TyRawPtr(mt) if explicit => Some(mt),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
/// Returns the type of `ty[i]`.
|
|
pub fn builtin_index(&self) -> Option<Ty<'tcx>> {
|
|
match self.sty {
|
|
TyArray(ty, _) | TySlice(ty) => Some(ty),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
pub fn fn_sig(&self, tcx: TyCtxt<'a, 'gcx, 'tcx>) -> PolyFnSig<'tcx> {
|
|
match self.sty {
|
|
TyFnDef(def_id, substs) => {
|
|
tcx.fn_sig(def_id).subst(tcx, substs)
|
|
}
|
|
TyFnPtr(f) => f,
|
|
_ => bug!("Ty::fn_sig() called on non-fn type: {:?}", self)
|
|
}
|
|
}
|
|
|
|
pub fn is_fn(&self) -> bool {
|
|
match self.sty {
|
|
TyFnDef(..) | TyFnPtr(_) => true,
|
|
_ => false,
|
|
}
|
|
}
|
|
|
|
pub fn ty_to_def_id(&self) -> Option<DefId> {
|
|
match self.sty {
|
|
TyDynamic(ref tt, ..) => tt.principal().map(|p| p.def_id()),
|
|
TyAdt(def, _) => Some(def.did),
|
|
TyForeign(did) => Some(did),
|
|
TyClosure(id, _) => Some(id),
|
|
TyFnDef(id, _) => Some(id),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
pub fn ty_adt_def(&self) -> Option<&'tcx AdtDef> {
|
|
match self.sty {
|
|
TyAdt(adt, _) => Some(adt),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
/// Returns the regions directly referenced from this type (but
|
|
/// not types reachable from this type via `walk_tys`). This
|
|
/// ignores late-bound regions binders.
|
|
pub fn regions(&self) -> Vec<ty::Region<'tcx>> {
|
|
match self.sty {
|
|
TyRef(region, _, _) => {
|
|
vec![region]
|
|
}
|
|
TyDynamic(ref obj, region) => {
|
|
let mut v = vec![region];
|
|
if let Some(p) = obj.principal() {
|
|
v.extend(p.skip_binder().substs.regions());
|
|
}
|
|
v
|
|
}
|
|
TyAdt(_, substs) | TyAnon(_, substs) => {
|
|
substs.regions().collect()
|
|
}
|
|
TyClosure(_, ClosureSubsts { ref substs }) |
|
|
TyGenerator(_, GeneratorSubsts { ref substs }, _) => {
|
|
substs.regions().collect()
|
|
}
|
|
TyProjection(ref data) => {
|
|
data.substs.regions().collect()
|
|
}
|
|
TyFnDef(..) |
|
|
TyFnPtr(_) |
|
|
TyGeneratorWitness(..) |
|
|
TyBool |
|
|
TyChar |
|
|
TyInt(_) |
|
|
TyUint(_) |
|
|
TyFloat(_) |
|
|
TyStr |
|
|
TyArray(..) |
|
|
TySlice(_) |
|
|
TyRawPtr(_) |
|
|
TyNever |
|
|
TyTuple(..) |
|
|
TyForeign(..) |
|
|
TyParam(_) |
|
|
TyInfer(_) |
|
|
TyError => {
|
|
vec![]
|
|
}
|
|
}
|
|
}
|
|
|
|
/// 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.sty {
|
|
TyInt(int_ty) => match int_ty {
|
|
ast::IntTy::I8 => Some(ty::ClosureKind::Fn),
|
|
ast::IntTy::I16 => Some(ty::ClosureKind::FnMut),
|
|
ast::IntTy::I32 => Some(ty::ClosureKind::FnOnce),
|
|
_ => bug!("cannot convert type `{:?}` to a closure kind", self),
|
|
},
|
|
|
|
TyInfer(_) => None,
|
|
|
|
TyError => Some(ty::ClosureKind::Fn),
|
|
|
|
_ => bug!("cannot convert type `{:?}` to a closure kind", self),
|
|
}
|
|
}
|
|
}
|
|
|
|
/// Typed constant value.
|
|
#[derive(Copy, Clone, Debug, Hash, RustcEncodable, RustcDecodable, Eq, PartialEq, Ord, PartialOrd)]
|
|
pub struct Const<'tcx> {
|
|
pub ty: Ty<'tcx>,
|
|
|
|
pub val: ConstVal<'tcx>,
|
|
}
|
|
|
|
impl<'tcx> Const<'tcx> {
|
|
pub fn unevaluated(
|
|
tcx: TyCtxt<'_, '_, 'tcx>,
|
|
def_id: DefId,
|
|
substs: &'tcx Substs<'tcx>,
|
|
ty: Ty<'tcx>,
|
|
) -> &'tcx Self {
|
|
tcx.mk_const(Const {
|
|
val: ConstVal::Unevaluated(def_id, substs),
|
|
ty,
|
|
})
|
|
}
|
|
|
|
#[inline]
|
|
pub fn from_const_val(
|
|
tcx: TyCtxt<'_, '_, 'tcx>,
|
|
val: ConstVal<'tcx>,
|
|
ty: Ty<'tcx>,
|
|
) -> &'tcx Self {
|
|
tcx.mk_const(Const {
|
|
val,
|
|
ty,
|
|
})
|
|
}
|
|
|
|
#[inline]
|
|
pub fn from_const_value(
|
|
tcx: TyCtxt<'_, '_, 'tcx>,
|
|
val: ConstValue<'tcx>,
|
|
ty: Ty<'tcx>,
|
|
) -> &'tcx Self {
|
|
Self::from_const_val(tcx, ConstVal::Value(val), ty)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn from_byval_value(
|
|
tcx: TyCtxt<'_, '_, 'tcx>,
|
|
val: Value,
|
|
ty: Ty<'tcx>,
|
|
) -> &'tcx Self {
|
|
Self::from_const_value(tcx, ConstValue::from_byval_value(val), ty)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn from_primval(
|
|
tcx: TyCtxt<'_, '_, 'tcx>,
|
|
val: PrimVal,
|
|
ty: Ty<'tcx>,
|
|
) -> &'tcx Self {
|
|
Self::from_const_value(tcx, ConstValue::from_primval(val), ty)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn from_bits(
|
|
tcx: TyCtxt<'_, '_, 'tcx>,
|
|
val: u128,
|
|
ty: Ty<'tcx>,
|
|
) -> &'tcx Self {
|
|
Self::from_primval(tcx, PrimVal::Bytes(val), ty)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn zero_sized(tcx: TyCtxt<'_, '_, 'tcx>, ty: Ty<'tcx>) -> &'tcx Self {
|
|
Self::from_primval(tcx, PrimVal::Undef, ty)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn from_bool(tcx: TyCtxt<'_, '_, 'tcx>, v: bool) -> &'tcx Self {
|
|
Self::from_bits(tcx, v as u128, tcx.types.bool)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn from_usize(tcx: TyCtxt<'_, '_, 'tcx>, n: u64) -> &'tcx Self {
|
|
Self::from_bits(tcx, n as u128, tcx.types.usize)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn to_bits(&self, ty: Ty<'_>) -> Option<u128> {
|
|
if self.ty != ty {
|
|
return None;
|
|
}
|
|
match self.val {
|
|
ConstVal::Value(val) => val.to_bits(),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn to_ptr(&self) -> Option<MemoryPointer> {
|
|
match self.val {
|
|
ConstVal::Value(val) => val.to_ptr(),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn to_byval_value(&self) -> Option<Value> {
|
|
match self.val {
|
|
ConstVal::Value(val) => val.to_byval_value(),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn to_primval(&self) -> Option<PrimVal> {
|
|
match self.val {
|
|
ConstVal::Value(val) => val.to_primval(),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn assert_bits(&self, ty: Ty<'_>) -> Option<u128> {
|
|
assert_eq!(self.ty, ty);
|
|
match self.val {
|
|
ConstVal::Value(val) => val.to_bits(),
|
|
_ => None,
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn assert_bool(&self, tcx: TyCtxt<'_, '_, '_>) -> Option<bool> {
|
|
self.assert_bits(tcx.types.bool).and_then(|v| match v {
|
|
0 => Some(false),
|
|
1 => Some(true),
|
|
_ => None,
|
|
})
|
|
}
|
|
|
|
#[inline]
|
|
pub fn assert_usize(&self, tcx: TyCtxt<'_, '_, '_>) -> Option<u64> {
|
|
self.assert_bits(tcx.types.usize).map(|v| v as u64)
|
|
}
|
|
|
|
#[inline]
|
|
pub fn unwrap_bits(&self, ty: Ty<'_>) -> u128 {
|
|
match self.assert_bits(ty) {
|
|
Some(val) => val,
|
|
None => bug!("expected bits of {}, got {:#?}", ty, self),
|
|
}
|
|
}
|
|
|
|
#[inline]
|
|
pub fn unwrap_usize(&self, tcx: TyCtxt<'_, '_, '_>) -> u64 {
|
|
match self.assert_usize(tcx) {
|
|
Some(val) => val,
|
|
None => bug!("expected constant usize, got {:#?}", self),
|
|
}
|
|
}
|
|
}
|
|
|
|
impl<'tcx> serialize::UseSpecializedDecodable for &'tcx Const<'tcx> {}
|