Google Git
Sign in
fuchsia / third_party / rust / 541858ed787a66bbb00a4edd21f924ed0f208a9d / . / compiler / rustc_middle / src / ty / sty.rs
blob: 6e0a9eb86dde727d7b52e758b7a17b3fe921f3c1 [file] [log] [blame]
//! This module contains `TyKind` and its major components.
#![allow(rustc::usage_of_ty_tykind)]
use crate::infer::canonical::Canonical;
use crate::ty::visit::ValidateBoundVars;
use crate::ty::InferTy::*;
use crate::ty::{
self, AdtDef, BoundRegionKind, Discr, Region, Ty, TyCtxt, TypeFlags, TypeSuperVisitable,
TypeVisitable, TypeVisitableExt, TypeVisitor,
};
use crate::ty::{GenericArg, GenericArgs, GenericArgsRef};
use crate::ty::{List, ParamEnv};
use hir::def::DefKind;
use rustc_data_structures::captures::Captures;
use rustc_errors::{DiagArgValue, ErrorGuaranteed, IntoDiagArg, MultiSpan};
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_hir::LangItem;
use rustc_macros::HashStable;
use rustc_span::symbol::{sym, Symbol};
use rustc_span::{Span, DUMMY_SP};
use rustc_target::abi::{FieldIdx, VariantIdx, FIRST_VARIANT};
use rustc_target::spec::abi::{self, Abi};
use std::assert_matches::debug_assert_matches;
use std::borrow::Cow;
use std::ops::{ControlFlow, Deref, Range};
use ty::util::IntTypeExt;
use rustc_type_ir::BoundVar;
use rustc_type_ir::CollectAndApply;
use rustc_type_ir::DynKind;
use rustc_type_ir::TyKind as IrTyKind;
use rustc_type_ir::TyKind::*;
use rustc_type_ir::TypeAndMut as IrTypeAndMut;
use super::fold::FnMutDelegate;
use super::GenericParamDefKind;
// Re-export and re-parameterize some `I = TyCtxt<'tcx>` types here
#[rustc_diagnostic_item = "TyKind"]
pub type TyKind<'tcx> = IrTyKind<TyCtxt<'tcx>>;
pub type TypeAndMut<'tcx> = IrTypeAndMut<TyCtxt<'tcx>>;
pub trait Article {
fn article(&self) -> &'static str;
}
impl<'tcx> Article for TyKind<'tcx> {
/// Get the article ("a" or "an") to use with this type.
fn article(&self) -> &'static str {
match self {
Int(_) | Float(_) | Array(_, _) => "an",
Adt(def, _) if def.is_enum() => "an",
// This should never happen, but ICEing and causing the user's code
// to not compile felt too harsh.
Error(_) => "a",
_ => "a",
}
}
}
/// A closure can be modeled as a struct that looks like:
/// ```ignore (illustrative)
/// struct Closure<'l0...'li, T0...Tj, CK, CS, U>(...U);
/// ```
/// where:
///
/// - 'l0...'li and T0...Tj are the generic parameters
/// in scope on the function that defined the closure,
/// - CK represents the *closure kind* (Fn vs FnMut vs FnOnce). This
/// is rather hackily encoded via a scalar type. See
/// `Ty::to_opt_closure_kind` for details.
/// - CS represents the *closure signature*, representing as a `fn()`
/// type. For example, `fn(u32, u32) -> u32` would mean that the closure
/// implements `CK<(u32, u32), Output = u32>`, where `CK` is the trait
/// specified above.
/// - U is a type parameter representing the types of its upvars, tupled up
/// (borrowed, if appropriate; that is, if a U field represents a by-ref upvar,
/// and the up-var has the type `Foo`, then that field of U will be `&Foo`).
///
/// So, for example, given this function:
/// ```ignore (illustrative)
/// fn foo<'a, T>(data: &'a mut T) {
/// do(|| data.count += 1)
/// }
/// ```
/// the type of the closure would be something like:
/// ```ignore (illustrative)
/// struct Closure<'a, T, U>(...U);
/// ```
/// Note that the type of the upvar is not specified in the struct.
/// You may wonder how the impl would then be able to use the upvar,
/// if it doesn't know it's type? The answer is that the impl is
/// (conceptually) not fully generic over Closure but rather tied to
/// instances with the expected upvar types:
/// ```ignore (illustrative)
/// impl<'b, 'a, T> FnMut() for Closure<'a, T, (&'b mut &'a mut T,)> {
/// ...
/// }
/// ```
/// You can see that the *impl* fully specified the type of the upvar
/// and thus knows full well that `data` has type `&'b mut &'a mut T`.
/// (Here, I am assuming that `data` is mut-borrowed.)
///
/// Now, the last question you may ask is: Why include the upvar types
/// in an extra type parameter? The reason for this design is that the
/// upvar types can reference lifetimes that are internal to the
/// creating function. In my example above, for example, the lifetime
/// `'b` represents the scope of the closure itself; this is some
/// subset of `foo`, probably just the scope of the call to the to
/// `do()`. If we just had the lifetime/type parameters from the
/// enclosing function, we couldn't name this lifetime `'b`. Note that
/// there can also be lifetimes in the types of the upvars themselves,
/// if one of them happens to be a reference to something that the
/// creating fn owns.
///
/// OK, you say, so why not create a more minimal set of parameters
/// that just includes the extra lifetime parameters? The answer is
/// primarily that it would be hard --- we don't know at the time when
/// we create the closure type what the full types of the upvars are,
/// nor do we know which are borrowed and which are not. In this
/// design, we can just supply a fresh type parameter and figure that
/// out later.
///
/// All right, you say, but why include the type parameters from the
/// original function then? The answer is that codegen may need them
/// when monomorphizing, and they may not appear in the upvars. A
/// closure could capture no variables but still make use of some
/// in-scope type parameter with a bound (e.g., if our example above
/// had an extra `U: Default`, and the closure called `U::default()`).
///
/// There is another reason. This design (implicitly) prohibits
/// closures from capturing themselves (except via a trait
/// object). This simplifies closure inference considerably, since it
/// means that when we infer the kind of a closure or its upvars, we
/// don't have to handle cycles where the decisions we make for
/// closure C wind up influencing the decisions we ought to make for
/// closure C (which would then require fixed point iteration to
/// handle). Plus it fixes an ICE. :P
///
/// ## Coroutines
///
/// Coroutines are handled similarly in `CoroutineArgs`. The set of
/// type parameters is similar, but `CK` and `CS` are replaced by the
/// following type parameters:
///
/// * `GS`: The coroutine's "resume type", which is the type of the
/// argument passed to `resume`, and the type of `yield` expressions
/// inside the coroutine.
/// * `GY`: The "yield type", which is the type of values passed to
/// `yield` inside the coroutine.
/// * `GR`: The "return type", which is the type of value returned upon
/// completion of the coroutine.
/// * `GW`: The "coroutine witness".
#[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable, Lift)]
pub struct ClosureArgs<'tcx> {
/// Lifetime and type parameters from the enclosing function,
/// concatenated with a tuple containing the types of the upvars.
///
/// These are separated out because codegen wants to pass them around
/// when monomorphizing.
pub args: GenericArgsRef<'tcx>,
}
/// Struct returned by `split()`.
pub struct ClosureArgsParts<'tcx> {
/// This is the args of the typeck root.
pub parent_args: &'tcx [GenericArg<'tcx>],
/// Represents the maximum calling capability of the closure.
pub closure_kind_ty: Ty<'tcx>,
/// Captures the closure's signature. This closure signature is "tupled", and
/// thus has a peculiar signature of `extern "rust-call" fn((Args, ...)) -> Ty`.
pub closure_sig_as_fn_ptr_ty: Ty<'tcx>,
/// The upvars captured by the closure. Remains an inference variable
/// until the upvar analysis, which happens late in HIR typeck.
pub tupled_upvars_ty: Ty<'tcx>,
}
impl<'tcx> ClosureArgs<'tcx> {
/// Construct `ClosureArgs` from `ClosureArgsParts`, containing `Args`
/// for the closure parent, alongside additional closure-specific components.
pub fn new(tcx: TyCtxt<'tcx>, parts: ClosureArgsParts<'tcx>) -> ClosureArgs<'tcx> {
ClosureArgs {
args: tcx.mk_args_from_iter(parts.parent_args.iter().copied().chain([
parts.closure_kind_ty.into(),
parts.closure_sig_as_fn_ptr_ty.into(),
parts.tupled_upvars_ty.into(),
])),
}
}
/// Divides the closure args into their respective components.
/// The ordering assumed here must match that used by `ClosureArgs::new` above.
fn split(self) -> ClosureArgsParts<'tcx> {
match self.args[..] {
[ref parent_args @ .., closure_kind_ty, closure_sig_as_fn_ptr_ty, tupled_upvars_ty] => {
ClosureArgsParts {
parent_args,
closure_kind_ty: closure_kind_ty.expect_ty(),
closure_sig_as_fn_ptr_ty: closure_sig_as_fn_ptr_ty.expect_ty(),
tupled_upvars_ty: tupled_upvars_ty.expect_ty(),
}
}
_ => bug!("closure args missing synthetics"),
}
}
/// Returns the generic parameters of the closure's parent.
pub fn parent_args(self) -> &'tcx [GenericArg<'tcx>] {
self.split().parent_args
}
/// Returns an iterator over the list of types of captured paths by the closure.
/// In case there was a type error in figuring out the types of the captured path, an
/// empty iterator is returned.
#[inline]
pub fn upvar_tys(self) -> &'tcx List<Ty<'tcx>> {
match *self.tupled_upvars_ty().kind() {
TyKind::Error(_) => ty::List::empty(),
TyKind::Tuple(tys) => tys,
TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"),
ty => bug!("Unexpected representation of upvar types tuple {:?}", ty),
}
}
/// Returns the tuple type representing the upvars for this closure.
#[inline]
pub fn tupled_upvars_ty(self) -> Ty<'tcx> {
self.split().tupled_upvars_ty
}
/// Returns the closure kind for this closure; may return a type
/// variable during inference. To get the closure kind during
/// inference, use `infcx.closure_kind(args)`.
pub fn kind_ty(self) -> Ty<'tcx> {
self.split().closure_kind_ty
}
/// Returns the `fn` pointer type representing the closure signature for this
/// closure.
// FIXME(eddyb) this should be unnecessary, as the shallowly resolved
// type is known at the time of the creation of `ClosureArgs`,
// see `rustc_hir_analysis::check::closure`.
pub fn sig_as_fn_ptr_ty(self) -> Ty<'tcx> {
self.split().closure_sig_as_fn_ptr_ty
}
/// Returns the closure kind for this closure; only usable outside
/// of an inference context, because in that context we know that
/// there are no type variables.
///
/// If you have an inference context, use `infcx.closure_kind()`.
pub fn kind(self) -> ty::ClosureKind {
self.kind_ty().to_opt_closure_kind().unwrap()
}
/// Extracts the signature from the closure.
pub fn sig(self) -> ty::PolyFnSig<'tcx> {
match *self.sig_as_fn_ptr_ty().kind() {
ty::FnPtr(sig) => sig,
ty => bug!("closure_sig_as_fn_ptr_ty is not a fn-ptr: {ty:?}"),
}
}
pub fn print_as_impl_trait(self) -> ty::print::PrintClosureAsImpl<'tcx> {
ty::print::PrintClosureAsImpl { closure: self }
}
}
#[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable, Lift)]
pub struct CoroutineClosureArgs<'tcx> {
pub args: GenericArgsRef<'tcx>,
}
/// See docs for explanation of how each argument is used.
///
/// See [`CoroutineClosureSignature`] for how these arguments are put together
/// to make a callable [`FnSig`] suitable for typeck and borrowck.
pub struct CoroutineClosureArgsParts<'tcx> {
/// This is the args of the typeck root.
pub parent_args: &'tcx [GenericArg<'tcx>],
/// Represents the maximum calling capability of the closure.
pub closure_kind_ty: Ty<'tcx>,
/// Represents all of the relevant parts of the coroutine returned by this
/// coroutine-closure. This signature parts type will have the general
/// shape of `fn(tupled_inputs, resume_ty) -> (return_ty, yield_ty)`, where
/// `resume_ty`, `return_ty`, and `yield_ty` are the respective types for the
/// coroutine returned by the coroutine-closure.
///
/// Use `coroutine_closure_sig` to break up this type rather than using it
/// yourself.
pub signature_parts_ty: Ty<'tcx>,
/// The upvars captured by the closure. Remains an inference variable
/// until the upvar analysis, which happens late in HIR typeck.
pub tupled_upvars_ty: Ty<'tcx>,
/// a function pointer that has the shape `for<'env> fn() -> (&'env T, ...)`.
/// This allows us to represent the binder of the self-captures of the closure.
///
/// For example, if the coroutine returned by the closure borrows `String`
/// from the closure's upvars, this will be `for<'env> fn() -> (&'env String,)`,
/// while the `tupled_upvars_ty`, representing the by-move version of the same
/// captures, will be `(String,)`.
pub coroutine_captures_by_ref_ty: Ty<'tcx>,
/// Witness type returned by the generator produced by this coroutine-closure.
pub coroutine_witness_ty: Ty<'tcx>,
}
impl<'tcx> CoroutineClosureArgs<'tcx> {
pub fn new(
tcx: TyCtxt<'tcx>,
parts: CoroutineClosureArgsParts<'tcx>,
) -> CoroutineClosureArgs<'tcx> {
CoroutineClosureArgs {
args: tcx.mk_args_from_iter(parts.parent_args.iter().copied().chain([
parts.closure_kind_ty.into(),
parts.signature_parts_ty.into(),
parts.tupled_upvars_ty.into(),
parts.coroutine_captures_by_ref_ty.into(),
parts.coroutine_witness_ty.into(),
])),
}
}
fn split(self) -> CoroutineClosureArgsParts<'tcx> {
match self.args[..] {
[
ref parent_args @ ..,
closure_kind_ty,
signature_parts_ty,
tupled_upvars_ty,
coroutine_captures_by_ref_ty,
coroutine_witness_ty,
] => CoroutineClosureArgsParts {
parent_args,
closure_kind_ty: closure_kind_ty.expect_ty(),
signature_parts_ty: signature_parts_ty.expect_ty(),
tupled_upvars_ty: tupled_upvars_ty.expect_ty(),
coroutine_captures_by_ref_ty: coroutine_captures_by_ref_ty.expect_ty(),
coroutine_witness_ty: coroutine_witness_ty.expect_ty(),
},
_ => bug!("closure args missing synthetics"),
}
}
pub fn parent_args(self) -> &'tcx [GenericArg<'tcx>] {
self.split().parent_args
}
#[inline]
pub fn upvar_tys(self) -> &'tcx List<Ty<'tcx>> {
match self.tupled_upvars_ty().kind() {
TyKind::Error(_) => ty::List::empty(),
TyKind::Tuple(..) => 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),
}
}
#[inline]
pub fn tupled_upvars_ty(self) -> Ty<'tcx> {
self.split().tupled_upvars_ty
}
pub fn kind_ty(self) -> Ty<'tcx> {
self.split().closure_kind_ty
}
pub fn kind(self) -> ty::ClosureKind {
self.kind_ty().to_opt_closure_kind().unwrap()
}
pub fn signature_parts_ty(self) -> Ty<'tcx> {
self.split().signature_parts_ty
}
pub fn coroutine_closure_sig(self) -> ty::Binder<'tcx, CoroutineClosureSignature<'tcx>> {
let interior = self.coroutine_witness_ty();
let ty::FnPtr(sig) = self.signature_parts_ty().kind() else { bug!() };
sig.map_bound(|sig| {
let [resume_ty, tupled_inputs_ty] = *sig.inputs() else {
bug!();
};
let [yield_ty, return_ty] = **sig.output().tuple_fields() else { bug!() };
CoroutineClosureSignature {
interior,
tupled_inputs_ty,
resume_ty,
yield_ty,
return_ty,
c_variadic: sig.c_variadic,
unsafety: sig.unsafety,
abi: sig.abi,
}
})
}
pub fn coroutine_captures_by_ref_ty(self) -> Ty<'tcx> {
self.split().coroutine_captures_by_ref_ty
}
pub fn coroutine_witness_ty(self) -> Ty<'tcx> {
self.split().coroutine_witness_ty
}
}
#[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable)]
pub struct CoroutineClosureSignature<'tcx> {
pub interior: Ty<'tcx>,
pub tupled_inputs_ty: Ty<'tcx>,
pub resume_ty: Ty<'tcx>,
pub yield_ty: Ty<'tcx>,
pub return_ty: Ty<'tcx>,
// Like the `fn_sig_as_fn_ptr_ty` of a regular closure, these types
// never actually differ. But we save them rather than recreating them
// from scratch just for good measure.
/// Always false
pub c_variadic: bool,
/// Always [`hir::Unsafety::Normal`]
pub unsafety: hir::Unsafety,
/// Always [`abi::Abi::RustCall`]
pub abi: abi::Abi,
}
impl<'tcx> CoroutineClosureSignature<'tcx> {
/// Construct a coroutine from the closure signature. Since a coroutine signature
/// is agnostic to the type of generator that is returned (by-ref/by-move),
/// the caller must specify what "flavor" of generator that they'd like to
/// create. Additionally, they must manually compute the upvars of the closure.
///
/// This helper is not really meant to be used directly except for early on
/// during typeck, when we want to put inference vars into the kind and upvars tys.
/// When the kind and upvars are known, use the other helper functions.
pub fn to_coroutine(
self,
tcx: TyCtxt<'tcx>,
parent_args: &'tcx [GenericArg<'tcx>],
coroutine_kind_ty: Ty<'tcx>,
coroutine_def_id: DefId,
tupled_upvars_ty: Ty<'tcx>,
) -> Ty<'tcx> {
let coroutine_args = ty::CoroutineArgs::new(
tcx,
ty::CoroutineArgsParts {
parent_args,
kind_ty: coroutine_kind_ty,
resume_ty: self.resume_ty,
yield_ty: self.yield_ty,
return_ty: self.return_ty,
witness: self.interior,
tupled_upvars_ty,
},
);
Ty::new_coroutine(tcx, coroutine_def_id, coroutine_args.args)
}
/// Given known upvars and a [`ClosureKind`](ty::ClosureKind), compute the coroutine
/// returned by that corresponding async fn trait.
///
/// This function expects the upvars to have been computed already, and doesn't check
/// that the `ClosureKind` is actually supported by the coroutine-closure.
pub fn to_coroutine_given_kind_and_upvars(
self,
tcx: TyCtxt<'tcx>,
parent_args: &'tcx [GenericArg<'tcx>],
coroutine_def_id: DefId,
goal_kind: ty::ClosureKind,
env_region: ty::Region<'tcx>,
closure_tupled_upvars_ty: Ty<'tcx>,
coroutine_captures_by_ref_ty: Ty<'tcx>,
) -> Ty<'tcx> {
let tupled_upvars_ty = Self::tupled_upvars_by_closure_kind(
tcx,
goal_kind,
self.tupled_inputs_ty,
closure_tupled_upvars_ty,
coroutine_captures_by_ref_ty,
env_region,
);
self.to_coroutine(
tcx,
parent_args,
Ty::from_coroutine_closure_kind(tcx, goal_kind),
coroutine_def_id,
tupled_upvars_ty,
)
}
/// Compute the tupled upvars that a coroutine-closure's output coroutine
/// would return for the given `ClosureKind`.
///
/// When `ClosureKind` is `FnMut`/`Fn`, then this will use the "captures by ref"
/// to return a set of upvars which are borrowed with the given `env_region`.
///
/// This ensures that the `AsyncFn::call` will return a coroutine whose upvars'
/// lifetimes are related to the lifetime of the borrow on the closure made for
/// the call. This allows borrowck to enforce the self-borrows correctly.
pub fn tupled_upvars_by_closure_kind(
tcx: TyCtxt<'tcx>,
kind: ty::ClosureKind,
tupled_inputs_ty: Ty<'tcx>,
closure_tupled_upvars_ty: Ty<'tcx>,
coroutine_captures_by_ref_ty: Ty<'tcx>,
env_region: ty::Region<'tcx>,
) -> Ty<'tcx> {
match kind {
ty::ClosureKind::Fn | ty::ClosureKind::FnMut => {
let ty::FnPtr(sig) = *coroutine_captures_by_ref_ty.kind() else {
bug!();
};
let coroutine_captures_by_ref_ty = tcx.replace_escaping_bound_vars_uncached(
sig.output().skip_binder(),
FnMutDelegate {
consts: &mut |c, t| ty::Const::new_bound(tcx, ty::INNERMOST, c, t),
types: &mut |t| Ty::new_bound(tcx, ty::INNERMOST, t),
regions: &mut |_| env_region,
},
);
Ty::new_tup_from_iter(
tcx,
tupled_inputs_ty
.tuple_fields()
.iter()
.chain(coroutine_captures_by_ref_ty.tuple_fields()),
)
}
ty::ClosureKind::FnOnce => Ty::new_tup_from_iter(
tcx,
tupled_inputs_ty
.tuple_fields()
.iter()
.chain(closure_tupled_upvars_ty.tuple_fields()),
),
}
}
}
/// Similar to `ClosureArgs`; see the above documentation for more.
#[derive(Copy, Clone, PartialEq, Eq, Debug, TypeFoldable, TypeVisitable)]
pub struct CoroutineArgs<'tcx> {
pub args: GenericArgsRef<'tcx>,
}
pub struct CoroutineArgsParts<'tcx> {
/// This is the args of the typeck root.
pub parent_args: &'tcx [GenericArg<'tcx>],
/// The coroutines returned by a coroutine-closure's `AsyncFnOnce`/`AsyncFnMut`
/// implementations must be distinguished since the former takes the closure's
/// upvars by move, and the latter takes the closure's upvars by ref.
///
/// This field distinguishes these fields so that codegen can select the right
/// body for the coroutine. This has the same type representation as the closure
/// kind: `i8`/`i16`/`i32`.
///
/// For regular coroutines, this field will always just be `()`.
pub kind_ty: Ty<'tcx>,
pub resume_ty: Ty<'tcx>,
pub yield_ty: Ty<'tcx>,
pub return_ty: Ty<'tcx>,
/// The interior type of the coroutine.
/// Represents all types that are stored in locals
/// in the coroutine's body.
pub witness: Ty<'tcx>,
/// The upvars captured by the closure. Remains an inference variable
/// until the upvar analysis, which happens late in HIR typeck.
pub tupled_upvars_ty: Ty<'tcx>,
}
impl<'tcx> CoroutineArgs<'tcx> {
/// Construct `CoroutineArgs` from `CoroutineArgsParts`, containing `Args`
/// for the coroutine parent, alongside additional coroutine-specific components.
pub fn new(tcx: TyCtxt<'tcx>, parts: CoroutineArgsParts<'tcx>) -> CoroutineArgs<'tcx> {
CoroutineArgs {
args: tcx.mk_args_from_iter(parts.parent_args.iter().copied().chain([
parts.kind_ty.into(),
parts.resume_ty.into(),
parts.yield_ty.into(),
parts.return_ty.into(),
parts.witness.into(),
parts.tupled_upvars_ty.into(),
])),
}
}
/// Divides the coroutine args into their respective components.
/// The ordering assumed here must match that used by `CoroutineArgs::new` above.
fn split(self) -> CoroutineArgsParts<'tcx> {
match self.args[..] {
[
ref parent_args @ ..,
kind_ty,
resume_ty,
yield_ty,
return_ty,
witness,
tupled_upvars_ty,
] => CoroutineArgsParts {
parent_args,
kind_ty: kind_ty.expect_ty(),
resume_ty: resume_ty.expect_ty(),
yield_ty: yield_ty.expect_ty(),
return_ty: return_ty.expect_ty(),
witness: witness.expect_ty(),
tupled_upvars_ty: tupled_upvars_ty.expect_ty(),
},
_ => bug!("coroutine args missing synthetics"),
}
}
/// Returns the generic parameters of the coroutine's parent.
pub fn parent_args(self) -> &'tcx [GenericArg<'tcx>] {
self.split().parent_args
}
// Returns the kind of the coroutine. See docs on the `kind_ty` field.
pub fn kind_ty(self) -> Ty<'tcx> {
self.split().kind_ty
}
/// This describes the types that can be contained in a coroutine.
/// 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 coroutine 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
}
/// Returns an iterator over the list of types of captured paths by the coroutine.
/// 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) -> &'tcx List<Ty<'tcx>> {
match *self.tupled_upvars_ty().kind() {
TyKind::Error(_) => ty::List::empty(),
TyKind::Tuple(tys) => tys,
TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"),
ty => bug!("Unexpected representation of upvar types tuple {:?}", ty),
}
}
/// Returns the tuple type representing the upvars for this coroutine.
#[inline]
pub fn tupled_upvars_ty(self) -> Ty<'tcx> {
self.split().tupled_upvars_ty
}
/// Returns the type representing the resume type of the coroutine.
pub fn resume_ty(self) -> Ty<'tcx> {
self.split().resume_ty
}
/// Returns the type representing the yield type of the coroutine.
pub fn yield_ty(self) -> Ty<'tcx> {
self.split().yield_ty
}
/// Returns the type representing the return type of the coroutine.
pub fn return_ty(self) -> Ty<'tcx> {
self.split().return_ty
}
/// Returns the "coroutine signature", which consists of its resume, yield
/// and return types.
pub fn sig(self) -> GenSig<'tcx> {
let parts = self.split();
ty::GenSig {
resume_ty: parts.resume_ty,
yield_ty: parts.yield_ty,
return_ty: parts.return_ty,
}
}
}
impl<'tcx> CoroutineArgs<'tcx> {
/// Coroutine has not been resumed yet.
pub const UNRESUMED: usize = 0;
/// Coroutine has returned or is completed.
pub const RETURNED: usize = 1;
/// Coroutine 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 coroutine.
#[inline]
pub fn variant_range(&self, def_id: DefId, tcx: TyCtxt<'tcx>) -> Range<VariantIdx> {
// FIXME requires optimized MIR
FIRST_VARIANT..tcx.coroutine_layout(def_id).unwrap().variant_fields.next_index()
}
/// 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> {
// Coroutines 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 coroutine, 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 coroutine 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::coroutine::StateTransform.
/// All the types here must be in the tuple in CoroutineInterior.
///
/// The locals are grouped by their variant number. Note that some locals may
/// be repeated in multiple variants.
#[inline]
pub fn state_tys(
self,
def_id: DefId,
tcx: TyCtxt<'tcx>,
) -> impl Iterator<Item: Iterator<Item = Ty<'tcx>> + Captures<'tcx>> {
let layout = tcx.coroutine_layout(def_id).unwrap();
layout.variant_fields.iter().map(move |variant| {
variant.iter().map(move |field| {
ty::EarlyBinder::bind(layout.field_tys[*field].ty).instantiate(tcx, self.args)
})
})
}
/// This is the types of the fields of a coroutine which are not stored in a
/// variant.
#[inline]
pub fn prefix_tys(self) -> &'tcx List<Ty<'tcx>> {
self.upvar_tys()
}
}
#[derive(Debug, Copy, Clone, HashStable)]
pub enum UpvarArgs<'tcx> {
Closure(GenericArgsRef<'tcx>),
Coroutine(GenericArgsRef<'tcx>),
CoroutineClosure(GenericArgsRef<'tcx>),
}
impl<'tcx> UpvarArgs<'tcx> {
/// Returns an iterator over the list of types of captured paths by the closure/coroutine.
/// 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) -> &'tcx List<Ty<'tcx>> {
let tupled_tys = match self {
UpvarArgs::Closure(args) => args.as_closure().tupled_upvars_ty(),
UpvarArgs::Coroutine(args) => args.as_coroutine().tupled_upvars_ty(),
UpvarArgs::CoroutineClosure(args) => args.as_coroutine_closure().tupled_upvars_ty(),
};
match tupled_tys.kind() {
TyKind::Error(_) => ty::List::empty(),
TyKind::Tuple(..) => 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),
}
}
#[inline]
pub fn tupled_upvars_ty(self) -> Ty<'tcx> {
match self {
UpvarArgs::Closure(args) => args.as_closure().tupled_upvars_ty(),
UpvarArgs::Coroutine(args) => args.as_coroutine().tupled_upvars_ty(),
UpvarArgs::CoroutineClosure(args) => args.as_coroutine_closure().tupled_upvars_ty(),
}
}
}
/// An inline const is modeled like
/// ```ignore (illustrative)
/// const InlineConst<'l0...'li, T0...Tj, R>: R;
/// ```
/// where:
///
/// - 'l0...'li and T0...Tj are the generic parameters
/// inherited from the item that defined the inline const,
/// - R represents the type of the constant.
///
/// When the inline const is instantiated, `R` is instantiated as the actual inferred
/// type of the constant. The reason that `R` is represented as an extra type parameter
/// is the same reason that [`ClosureArgs`] have `CS` and `U` as type parameters:
/// inline const can reference lifetimes that are internal to the creating function.
#[derive(Copy, Clone, Debug)]
pub struct InlineConstArgs<'tcx> {
/// Generic parameters from the enclosing item,
/// concatenated with the inferred type of the constant.
pub args: GenericArgsRef<'tcx>,
}
/// Struct returned by `split()`.
pub struct InlineConstArgsParts<'tcx, T> {
pub parent_args: &'tcx [GenericArg<'tcx>],
pub ty: T,
}
impl<'tcx> InlineConstArgs<'tcx> {
/// Construct `InlineConstArgs` from `InlineConstArgsParts`.
pub fn new(
tcx: TyCtxt<'tcx>,
parts: InlineConstArgsParts<'tcx, Ty<'tcx>>,
) -> InlineConstArgs<'tcx> {
InlineConstArgs {
args: tcx.mk_args_from_iter(
parts.parent_args.iter().copied().chain(std::iter::once(parts.ty.into())),
),
}
}
/// Divides the inline const args into their respective components.
/// The ordering assumed here must match that used by `InlineConstArgs::new` above.
fn split(self) -> InlineConstArgsParts<'tcx, GenericArg<'tcx>> {
match self.args[..] {
[ref parent_args @ .., ty] => InlineConstArgsParts { parent_args, ty },
_ => bug!("inline const args missing synthetics"),
}
}
/// Returns the generic parameters of the inline const's parent.
pub fn parent_args(self) -> &'tcx [GenericArg<'tcx>] {
self.split().parent_args
}
/// Returns the type of this inline const.
pub fn ty(self) -> Ty<'tcx> {
self.split().ty.expect_ty()
}
}
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
#[derive(HashStable)]
pub enum BoundVariableKind {
Ty(BoundTyKind),
Region(BoundRegionKind),
Const,
}
impl BoundVariableKind {
pub fn expect_region(self) -> BoundRegionKind {
match self {
BoundVariableKind::Region(lt) => lt,
_ => bug!("expected a region, but found another kind"),
}
}
pub fn expect_ty(self) -> BoundTyKind {
match self {
BoundVariableKind::Ty(ty) => ty,
_ => bug!("expected a type, but found another kind"),
}
}
pub fn expect_const(self) {
match self {
BoundVariableKind::Const => (),
_ => bug!("expected a const, but found another kind"),
}
}
}
/// Binder is a binder for higher-ranked lifetimes or types. It is part of the
/// compiler's representation for things like `for<'a> Fn(&'a isize)`
/// (which would be represented by the type `PolyTraitRef ==
/// Binder<'tcx, TraitRef>`). Note that when we instantiate,
/// erase, or otherwise "discharge" these bound vars, we change the
/// type from `Binder<'tcx, T>` to just `T` (see
/// e.g., `liberate_late_bound_regions`).
///
/// `Decodable` and `Encodable` are implemented for `Binder<T>` using the `impl_binder_encode_decode!` macro.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
#[derive(HashStable, Lift)]
pub struct Binder<'tcx, T> {
value: T,
bound_vars: &'tcx List<BoundVariableKind>,
}
impl<'tcx, T> Binder<'tcx, T>
where
T: TypeVisitable<TyCtxt<'tcx>>,
{
/// Wraps `value` in a binder, asserting that `value` does not
/// contain any bound vars that would be bound by the
/// binder. This is commonly used to 'inject' a value T into a
/// different binding level.
#[track_caller]
pub fn dummy(value: T) -> Binder<'tcx, T> {
assert!(
!value.has_escaping_bound_vars(),
"`{value:?}` has escaping bound vars, so it cannot be wrapped in a dummy binder."
);
Binder { value, bound_vars: ty::List::empty() }
}
pub fn bind_with_vars(value: T, bound_vars: &'tcx List<BoundVariableKind>) -> Binder<'tcx, T> {
if cfg!(debug_assertions) {
let mut validator = ValidateBoundVars::new(bound_vars);
value.visit_with(&mut validator);
}
Binder { value, bound_vars }
}
}
impl<'tcx, T> rustc_type_ir::BoundVars<TyCtxt<'tcx>> for ty::Binder<'tcx, T> {
fn bound_vars(&self) -> &'tcx List<ty::BoundVariableKind> {
self.bound_vars
}
fn has_no_bound_vars(&self) -> bool {
self.bound_vars.is_empty()
}
}
impl<'tcx, T> Binder<'tcx, T> {
/// Skips the binder and returns the "bound" value. This is a
/// risky thing to do because it's easy to get confused about
/// De Bruijn indices and the like. It is usually better to
/// discharge the binder using `no_bound_vars` or
/// `instantiate_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.value
}
pub fn bound_vars(&self) -> &'tcx List<BoundVariableKind> {
self.bound_vars
}
pub fn as_ref(&self) -> Binder<'tcx, &T> {
Binder { value: &self.value, bound_vars: self.bound_vars }
}
pub fn as_deref(&self) -> Binder<'tcx, &T::Target>
where
T: Deref,
{
Binder { value: &self.value, bound_vars: self.bound_vars }
}
pub fn map_bound_ref_unchecked<F, U>(&self, f: F) -> Binder<'tcx, U>
where
F: FnOnce(&T) -> U,
{
let value = f(&self.value);
Binder { value, bound_vars: self.bound_vars }
}
pub fn map_bound_ref<F, U: TypeVisitable<TyCtxt<'tcx>>>(&self, f: F) -> Binder<'tcx, U>
where
F: FnOnce(&T) -> U,
{
self.as_ref().map_bound(f)
}
pub fn map_bound<F, U: TypeVisitable<TyCtxt<'tcx>>>(self, f: F) -> Binder<'tcx, U>
where
F: FnOnce(T) -> U,
{
let Binder { value, bound_vars } = self;
let value = f(value);
if cfg!(debug_assertions) {
let mut validator = ValidateBoundVars::new(bound_vars);
value.visit_with(&mut validator);
}
Binder { value, bound_vars }
}
pub fn try_map_bound<F, U: TypeVisitable<TyCtxt<'tcx>>, E>(
self,
f: F,
) -> Result<Binder<'tcx, U>, E>
where
F: FnOnce(T) -> Result<U, E>,
{
let Binder { value, bound_vars } = self;
let value = f(value)?;
if cfg!(debug_assertions) {
let mut validator = ValidateBoundVars::new(bound_vars);
value.visit_with(&mut validator);
}
Ok(Binder { value, bound_vars })
}
/// Wraps a `value` in a binder, using the same bound variables as the
/// current `Binder`. This should not be used if the new value *changes*
/// the bound variables. Note: the (old or new) value itself does not
/// necessarily need to *name* all the bound variables.
///
/// This currently doesn't do anything different than `bind`, because we
/// don't actually track bound vars. However, semantically, it is different
/// because bound vars aren't allowed to change here, whereas they are
/// in `bind`. This may be (debug) asserted in the future.
pub fn rebind<U>(&self, value: U) -> Binder<'tcx, U>
where
U: TypeVisitable<TyCtxt<'tcx>>,
{
Binder::bind_with_vars(value, self.bound_vars)
}
/// Unwraps and returns the value within, but only if it contains
/// no bound vars at all. (In other words, if this binder --
/// and indeed any enclosing binder -- doesn't bind anything at
/// all.) Otherwise, returns `None`.
///
/// (One could imagine having a method that just unwraps a single
/// binder, but permits late-bound vars bound by enclosing
/// binders, but that would require adjusting the debruijn
/// indices, and given the shallow binding structure we often use,
/// would not be that useful.)
pub fn no_bound_vars(self) -> Option<T>
where
T: TypeVisitable<TyCtxt<'tcx>>,
{
// `self.value` is equivalent to `self.skip_binder()`
if self.value.has_escaping_bound_vars() { None } else { Some(self.skip_binder()) }
}
/// Splits the contents into two things that share the same binder
/// level as the original, returning two distinct binders.
///
/// `f` should consider bound regions at depth 1 to be free, and
/// anything it produces with bound regions at depth 1 will be
/// bound in the resulting return values.
pub fn split<U, V, F>(self, f: F) -> (Binder<'tcx, U>, Binder<'tcx, V>)
where
F: FnOnce(T) -> (U, V),
{
let Binder { value, bound_vars } = self;
let (u, v) = f(value);
(Binder { value: u, bound_vars }, Binder { value: v, bound_vars })
}
}
impl<'tcx, T> Binder<'tcx, Option<T>> {
pub fn transpose(self) -> Option<Binder<'tcx, T>> {
let Binder { value, bound_vars } = self;
value.map(|value| Binder { value, bound_vars })
}
}
impl<'tcx, T: IntoIterator> Binder<'tcx, T> {
pub fn iter(self) -> impl Iterator<Item = ty::Binder<'tcx, T::Item>> {
let Binder { value, bound_vars } = self;
value.into_iter().map(|value| Binder { value, bound_vars })
}
}
impl<'tcx, T> IntoDiagArg for Binder<'tcx, T>
where
T: IntoDiagArg,
{
fn into_diag_arg(self) -> DiagArgValue {
self.value.into_diag_arg()
}
}
/// Represents the projection of an associated type.
///
/// * For a projection, this would be `<Ty as Trait<...>>::N<...>`.
/// * For an inherent projection, this would be `Ty::N<...>`.
/// * For an opaque type, there is no explicit syntax.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
pub struct AliasTy<'tcx> {
/// The parameters of the associated or opaque item.
///
/// For a projection, these are the generic parameters for the trait and the
/// GAT parameters, if there are any.
///
/// For an inherent projection, they consist of the self type and the GAT parameters,
/// if there are any.
///
/// For RPIT the generic parameters are for the generics of the function,
/// while for TAIT it is used for the generic parameters of the alias.
pub args: GenericArgsRef<'tcx>,
/// The `DefId` of the `TraitItem` or `ImplItem` for the associated type `N` depending on whether
/// this is a projection or an inherent projection or the `DefId` of the `OpaqueType` item if
/// this is an opaque.
///
/// During codegen, `tcx.type_of(def_id)` can be used to get the type of the
/// underlying type if the type is an opaque.
///
/// Note that if this is an associated type, this is not the `DefId` of the
/// `TraitRef` containing this associated type, which is in `tcx.associated_item(def_id).container`,
/// aka. `tcx.parent(def_id)`.
pub def_id: DefId,
/// This field exists to prevent the creation of `AliasTy` without using
/// [AliasTy::new].
_use_alias_ty_new_instead: (),
}
impl<'tcx> AliasTy<'tcx> {
pub fn new(
tcx: TyCtxt<'tcx>,
def_id: DefId,
args: impl IntoIterator<Item: Into<GenericArg<'tcx>>>,
) -> ty::AliasTy<'tcx> {
let args = tcx.check_and_mk_args(def_id, args);
ty::AliasTy { def_id, args, _use_alias_ty_new_instead: () }
}
pub fn kind(self, tcx: TyCtxt<'tcx>) -> ty::AliasKind {
match tcx.def_kind(self.def_id) {
DefKind::AssocTy
if let DefKind::Impl { of_trait: false } =
tcx.def_kind(tcx.parent(self.def_id)) =>
{
ty::Inherent
}
DefKind::AssocTy => ty::Projection,
DefKind::OpaqueTy => ty::Opaque,
DefKind::TyAlias => ty::Weak,
kind => bug!("unexpected DefKind in AliasTy: {kind:?}"),
}
}
/// Whether this alias type is an opaque.
pub fn is_opaque(self, tcx: TyCtxt<'tcx>) -> bool {
matches!(self.opt_kind(tcx), Some(ty::Opaque))
}
/// FIXME: rename `AliasTy` to `AliasTerm` and always handle
/// constants. This function can then be removed.
pub fn opt_kind(self, tcx: TyCtxt<'tcx>) -> Option<ty::AliasKind> {
match tcx.def_kind(self.def_id) {
DefKind::AssocTy
if let DefKind::Impl { of_trait: false } =
tcx.def_kind(tcx.parent(self.def_id)) =>
{
Some(ty::Inherent)
}
DefKind::AssocTy => Some(ty::Projection),
DefKind::OpaqueTy => Some(ty::Opaque),
DefKind::TyAlias => Some(ty::Weak),
_ => None,
}
}
pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
Ty::new_alias(tcx, self.kind(tcx), self)
}
}
/// The following methods work only with associated type projections.
impl<'tcx> AliasTy<'tcx> {
pub fn self_ty(self) -> Ty<'tcx> {
self.args.type_at(0)
}
pub fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self {
AliasTy::new(tcx, self.def_id, [self_ty.into()].into_iter().chain(self.args.iter().skip(1)))
}
}
/// The following methods work only with trait associated type projections.
impl<'tcx> AliasTy<'tcx> {
pub fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId {
match tcx.def_kind(self.def_id) {
DefKind::AssocTy | DefKind::AssocConst => tcx.parent(self.def_id),
kind => bug!("expected a projection AliasTy; found {kind:?}"),
}
}
/// Extracts the underlying trait reference and own args from this projection.
/// For example, if this is a projection of `<T as StreamingIterator>::Item<'a>`,
/// then this function would return a `T: StreamingIterator` trait reference and `['a]` as the own args
pub fn trait_ref_and_own_args(
self,
tcx: TyCtxt<'tcx>,
) -> (ty::TraitRef<'tcx>, &'tcx [ty::GenericArg<'tcx>]) {
debug_assert!(matches!(tcx.def_kind(self.def_id), DefKind::AssocTy | DefKind::AssocConst));
let trait_def_id = self.trait_def_id(tcx);
let trait_generics = tcx.generics_of(trait_def_id);
(
ty::TraitRef::new(tcx, trait_def_id, self.args.truncate_to(tcx, trait_generics)),
&self.args[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 args for generic associated types
/// consider calling [Self::trait_ref_and_own_args] 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::new(tcx, def_id, self.args.truncate_to(tcx, tcx.generics_of(def_id)))
}
}
/// The following methods work only with inherent associated type projections.
impl<'tcx> AliasTy<'tcx> {
/// Transform the generic parameters to have the given `impl` args as the base and the GAT args on top of that.
///
/// Does the following transformation:
///
/// ```text
/// [Self, P_0...P_m] -> [I_0...I_n, P_0...P_m]
///
/// I_i impl args
/// P_j GAT args
/// ```
pub fn rebase_inherent_args_onto_impl(
self,
impl_args: ty::GenericArgsRef<'tcx>,
tcx: TyCtxt<'tcx>,
) -> ty::GenericArgsRef<'tcx> {
debug_assert_eq!(self.kind(tcx), ty::Inherent);
tcx.mk_args_from_iter(impl_args.into_iter().chain(self.args.into_iter().skip(1)))
}
}
#[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable)]
pub struct GenSig<'tcx> {
pub resume_ty: Ty<'tcx>,
pub yield_ty: Ty<'tcx>,
pub return_ty: Ty<'tcx>,
}
/// Signature of a function type, which we have arbitrarily
/// decided to use to refer to the input/output types.
///
/// - `inputs`: is the list of arguments and their modes.
/// - `output`: is the return type.
/// - `c_variadic`: indicates whether this is a C-variadic function.
#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
#[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
pub struct FnSig<'tcx> {
pub inputs_and_output: &'tcx List<Ty<'tcx>>,
pub c_variadic: bool,
pub unsafety: hir::Unsafety,
pub abi: abi::Abi,
}
impl<'tcx> FnSig<'tcx> {
pub fn inputs(&self) -> &'tcx [Ty<'tcx>] {
&self.inputs_and_output[..self.inputs_and_output.len() - 1]
}
pub fn output(&self) -> Ty<'tcx> {
self.inputs_and_output[self.inputs_and_output.len() - 1]
}
// Creates a minimal `FnSig` to be used when encountering a `TyKind::Error` in a fallible
// method.
fn fake() -> FnSig<'tcx> {
FnSig {
inputs_and_output: List::empty(),
c_variadic: false,
unsafety: hir::Unsafety::Normal,
abi: abi::Abi::Rust,
}
}
}
impl<'tcx> IntoDiagArg for FnSig<'tcx> {
fn into_diag_arg(self) -> DiagArgValue {
self.to_string().into_diag_arg()
}
}
pub type PolyFnSig<'tcx> = Binder<'tcx, FnSig<'tcx>>;
impl<'tcx> PolyFnSig<'tcx> {
#[inline]
pub fn inputs(&self) -> Binder<'tcx, &'tcx [Ty<'tcx>]> {
self.map_bound_ref_unchecked(|fn_sig| fn_sig.inputs())
}
#[inline]
#[track_caller]
pub fn input(&self, index: usize) -> ty::Binder<'tcx, Ty<'tcx>> {
self.map_bound_ref(|fn_sig| fn_sig.inputs()[index])
}
pub fn inputs_and_output(&self) -> ty::Binder<'tcx, &'tcx List<Ty<'tcx>>> {
self.map_bound_ref(|fn_sig| fn_sig.inputs_and_output)
}
#[inline]
pub fn output(&self) -> ty::Binder<'tcx, Ty<'tcx>> {
self.map_bound_ref(|fn_sig| fn_sig.output())
}
pub fn c_variadic(&self) -> bool {
self.skip_binder().c_variadic
}
pub fn unsafety(&self) -> hir::Unsafety {
self.skip_binder().unsafety
}
pub fn abi(&self) -> abi::Abi {
self.skip_binder().abi
}
pub fn is_fn_trait_compatible(&self) -> bool {
matches!(
self.skip_binder(),
ty::FnSig {
unsafety: rustc_hir::Unsafety::Normal,
abi: Abi::Rust,
c_variadic: false,
..
}
)
}
}
pub type CanonicalPolyFnSig<'tcx> = Canonical<'tcx, Binder<'tcx, FnSig<'tcx>>>;
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
#[derive(HashStable)]
pub struct ParamTy {
pub index: u32,
pub name: Symbol,
}
impl<'tcx> ParamTy {
pub fn new(index: u32, name: Symbol) -> ParamTy {
ParamTy { index, name }
}
pub fn for_def(def: &ty::GenericParamDef) -> ParamTy {
ParamTy::new(def.index, def.name)
}
#[inline]
pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
Ty::new_param(tcx, self.index, self.name)
}
pub fn span_from_generics(&self, tcx: TyCtxt<'tcx>, item_with_generics: DefId) -> Span {
let generics = tcx.generics_of(item_with_generics);
let type_param = generics.type_param(self, tcx);
tcx.def_span(type_param.def_id)
}
}
#[derive(Copy, Clone, Hash, TyEncodable, TyDecodable, Eq, PartialEq, Ord, PartialOrd)]
#[derive(HashStable)]
pub struct ParamConst {
pub index: u32,
pub name: Symbol,
}
impl ParamConst {
pub fn new(index: u32, name: Symbol) -> ParamConst {
ParamConst { index, name }
}
pub fn for_def(def: &ty::GenericParamDef) -> ParamConst {
ParamConst::new(def.index, def.name)
}
}
#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash, 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(DefId, Symbol),
}
impl From<BoundVar> for BoundTy {
fn from(var: BoundVar) -> Self {
BoundTy { var, kind: BoundTyKind::Anon }
}
}
/// Constructors for `Ty`
impl<'tcx> Ty<'tcx> {
/// Avoid using this in favour of more specific `new_*` methods, where possible.
/// The more specific methods will often optimize their creation.
#[allow(rustc::usage_of_ty_tykind)]
#[inline]
pub fn new(tcx: TyCtxt<'tcx>, st: TyKind<'tcx>) -> Ty<'tcx> {
tcx.mk_ty_from_kind(st)
}
#[inline]
pub fn new_infer(tcx: TyCtxt<'tcx>, infer: ty::InferTy) -> Ty<'tcx> {
Ty::new(tcx, TyKind::Infer(infer))
}
#[inline]
pub fn new_var(tcx: TyCtxt<'tcx>, v: ty::TyVid) -> Ty<'tcx> {
// Use a pre-interned one when possible.
tcx.types
.ty_vars
.get(v.as_usize())
.copied()
.unwrap_or_else(|| Ty::new(tcx, Infer(TyVar(v))))
}
#[inline]
pub fn new_int_var(tcx: TyCtxt<'tcx>, v: ty::IntVid) -> Ty<'tcx> {
Ty::new_infer(tcx, IntVar(v))
}
#[inline]
pub fn new_float_var(tcx: TyCtxt<'tcx>, v: ty::FloatVid) -> Ty<'tcx> {
Ty::new_infer(tcx, FloatVar(v))
}
#[inline]
pub fn new_fresh(tcx: TyCtxt<'tcx>, n: u32) -> Ty<'tcx> {
// Use a pre-interned one when possible.
tcx.types
.fresh_tys
.get(n as usize)
.copied()
.unwrap_or_else(|| Ty::new_infer(tcx, ty::FreshTy(n)))
}
#[inline]
pub fn new_fresh_int(tcx: TyCtxt<'tcx>, n: u32) -> Ty<'tcx> {
// Use a pre-interned one when possible.
tcx.types
.fresh_int_tys
.get(n as usize)
.copied()
.unwrap_or_else(|| Ty::new_infer(tcx, ty::FreshIntTy(n)))
}
#[inline]
pub fn new_fresh_float(tcx: TyCtxt<'tcx>, n: u32) -> Ty<'tcx> {
// Use a pre-interned one when possible.
tcx.types
.fresh_float_tys
.get(n as usize)
.copied()
.unwrap_or_else(|| Ty::new_infer(tcx, ty::FreshFloatTy(n)))
}
#[inline]
pub fn new_param(tcx: TyCtxt<'tcx>, index: u32, name: Symbol) -> Ty<'tcx> {
tcx.mk_ty_from_kind(Param(ParamTy { index, name }))
}
#[inline]
pub fn new_bound(
tcx: TyCtxt<'tcx>,
index: ty::DebruijnIndex,
bound_ty: ty::BoundTy,
) -> Ty<'tcx> {
Ty::new(tcx, Bound(index, bound_ty))
}
#[inline]
pub fn new_placeholder(tcx: TyCtxt<'tcx>, placeholder: ty::PlaceholderType) -> Ty<'tcx> {
Ty::new(tcx, Placeholder(placeholder))
}
#[inline]
pub fn new_alias(
tcx: TyCtxt<'tcx>,
kind: ty::AliasKind,
alias_ty: ty::AliasTy<'tcx>,
) -> Ty<'tcx> {
debug_assert_matches!(
(kind, tcx.def_kind(alias_ty.def_id)),
(ty::Opaque, DefKind::OpaqueTy)
| (ty::Projection | ty::Inherent, DefKind::AssocTy)
| (ty::Weak, DefKind::TyAlias)
);
Ty::new(tcx, Alias(kind, alias_ty))
}
#[inline]
pub fn new_opaque(tcx: TyCtxt<'tcx>, def_id: DefId, args: GenericArgsRef<'tcx>) -> Ty<'tcx> {
Ty::new_alias(tcx, ty::Opaque, AliasTy::new(tcx, def_id, args))
}
/// Constructs a `TyKind::Error` type with current `ErrorGuaranteed`
pub fn new_error(tcx: TyCtxt<'tcx>, guar: ErrorGuaranteed) -> Ty<'tcx> {
Ty::new(tcx, Error(guar))
}
/// Constructs a `TyKind::Error` type and registers a `span_delayed_bug` to ensure it gets used.
#[track_caller]
pub fn new_misc_error(tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
Ty::new_error_with_message(tcx, DUMMY_SP, "TyKind::Error constructed but no error reported")
}
/// Constructs a `TyKind::Error` type and registers a `span_delayed_bug` with the given `msg` to
/// ensure it gets used.
#[track_caller]
pub fn new_error_with_message<S: Into<MultiSpan>>(
tcx: TyCtxt<'tcx>,
span: S,
msg: impl Into<Cow<'static, str>>,
) -> Ty<'tcx> {
let reported = tcx.dcx().span_delayed_bug(span, msg);
Ty::new(tcx, Error(reported))
}
#[inline]
pub fn new_int(tcx: TyCtxt<'tcx>, i: ty::IntTy) -> Ty<'tcx> {
use ty::IntTy::*;
match i {
Isize => tcx.types.isize,
I8 => tcx.types.i8,
I16 => tcx.types.i16,
I32 => tcx.types.i32,
I64 => tcx.types.i64,
I128 => tcx.types.i128,
}
}
#[inline]
pub fn new_uint(tcx: TyCtxt<'tcx>, ui: ty::UintTy) -> Ty<'tcx> {
use ty::UintTy::*;
match ui {
Usize => tcx.types.usize,
U8 => tcx.types.u8,
U16 => tcx.types.u16,
U32 => tcx.types.u32,
U64 => tcx.types.u64,
U128 => tcx.types.u128,
}
}
#[inline]
pub fn new_float(tcx: TyCtxt<'tcx>, f: ty::FloatTy) -> Ty<'tcx> {
use ty::FloatTy::*;
match f {
F16 => tcx.types.f16,
F32 => tcx.types.f32,
F64 => tcx.types.f64,
F128 => tcx.types.f128,
}
}
#[inline]
pub fn new_ref(tcx: TyCtxt<'tcx>, r: Region<'tcx>, tm: TypeAndMut<'tcx>) -> Ty<'tcx> {
Ty::new(tcx, Ref(r, tm.ty, tm.mutbl))
}
#[inline]
pub fn new_mut_ref(tcx: TyCtxt<'tcx>, r: Region<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
Ty::new_ref(tcx, r, TypeAndMut { ty, mutbl: hir::Mutability::Mut })
}
#[inline]
pub fn new_imm_ref(tcx: TyCtxt<'tcx>, r: Region<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
Ty::new_ref(tcx, r, TypeAndMut { ty, mutbl: hir::Mutability::Not })
}
#[inline]
pub fn new_ptr(tcx: TyCtxt<'tcx>, tm: TypeAndMut<'tcx>) -> Ty<'tcx> {
Ty::new(tcx, RawPtr(tm))
}
#[inline]
pub fn new_mut_ptr(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
Ty::new_ptr(tcx, TypeAndMut { ty, mutbl: hir::Mutability::Mut })
}
#[inline]
pub fn new_imm_ptr(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
Ty::new_ptr(tcx, TypeAndMut { ty, mutbl: hir::Mutability::Not })
}
#[inline]
pub fn new_adt(tcx: TyCtxt<'tcx>, def: AdtDef<'tcx>, args: GenericArgsRef<'tcx>) -> Ty<'tcx> {
Ty::new(tcx, Adt(def, args))
}
#[inline]
pub fn new_foreign(tcx: TyCtxt<'tcx>, def_id: DefId) -> Ty<'tcx> {
Ty::new(tcx, Foreign(def_id))
}
#[inline]
pub fn new_array(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, n: u64) -> Ty<'tcx> {
Ty::new(tcx, Array(ty, ty::Const::from_target_usize(tcx, n)))
}
#[inline]
pub fn new_array_with_const_len(
tcx: TyCtxt<'tcx>,
ty: Ty<'tcx>,
ct: ty::Const<'tcx>,
) -> Ty<'tcx> {
Ty::new(tcx, Array(ty, ct))
}
#[inline]
pub fn new_slice(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
Ty::new(tcx, Slice(ty))
}
#[inline]
pub fn new_tup(tcx: TyCtxt<'tcx>, ts: &[Ty<'tcx>]) -> Ty<'tcx> {
if ts.is_empty() { tcx.types.unit } else { Ty::new(tcx, Tuple(tcx.mk_type_list(ts))) }
}
pub fn new_tup_from_iter<I, T>(tcx: TyCtxt<'tcx>, iter: I) -> T::Output
where
I: Iterator<Item = T>,
T: CollectAndApply<Ty<'tcx>, Ty<'tcx>>,
{
T::collect_and_apply(iter, |ts| Ty::new_tup(tcx, ts))
}
#[inline]
pub fn new_fn_def(
tcx: TyCtxt<'tcx>,
def_id: DefId,
args: impl IntoIterator<Item: Into<GenericArg<'tcx>>>,
) -> Ty<'tcx> {
let args = tcx.check_and_mk_args(def_id, args);
Ty::new(tcx, FnDef(def_id, args))
}
#[inline]
pub fn new_fn_ptr(tcx: TyCtxt<'tcx>, fty: PolyFnSig<'tcx>) -> Ty<'tcx> {
Ty::new(tcx, FnPtr(fty))
}
#[inline]
pub fn new_dynamic(
tcx: TyCtxt<'tcx>,
obj: &'tcx List<ty::PolyExistentialPredicate<'tcx>>,
reg: ty::Region<'tcx>,
repr: DynKind,
) -> Ty<'tcx> {
Ty::new(tcx, Dynamic(obj, reg, repr))
}
#[inline]
pub fn new_projection(
tcx: TyCtxt<'tcx>,
item_def_id: DefId,
args: impl IntoIterator<Item: Into<GenericArg<'tcx>>>,
) -> Ty<'tcx> {
Ty::new_alias(tcx, ty::Projection, AliasTy::new(tcx, item_def_id, args))
}
#[inline]
pub fn new_closure(
tcx: TyCtxt<'tcx>,
def_id: DefId,
closure_args: GenericArgsRef<'tcx>,
) -> Ty<'tcx> {
debug_assert_eq!(
closure_args.len(),
tcx.generics_of(tcx.typeck_root_def_id(def_id)).count() + 3,
"closure constructed with incorrect generic parameters"
);
Ty::new(tcx, Closure(def_id, closure_args))
}
#[inline]
pub fn new_coroutine_closure(
tcx: TyCtxt<'tcx>,
def_id: DefId,
closure_args: GenericArgsRef<'tcx>,
) -> Ty<'tcx> {
debug_assert_eq!(
closure_args.len(),
tcx.generics_of(tcx.typeck_root_def_id(def_id)).count() + 5,
"closure constructed with incorrect generic parameters"
);
Ty::new(tcx, CoroutineClosure(def_id, closure_args))
}
#[inline]
pub fn new_coroutine(
tcx: TyCtxt<'tcx>,
def_id: DefId,
coroutine_args: GenericArgsRef<'tcx>,
) -> Ty<'tcx> {
debug_assert_eq!(
coroutine_args.len(),
tcx.generics_of(tcx.typeck_root_def_id(def_id)).count() + 6,
"coroutine constructed with incorrect number of generic parameters"
);
Ty::new(tcx, Coroutine(def_id, coroutine_args))
}
#[inline]
pub fn new_coroutine_witness(
tcx: TyCtxt<'tcx>,
id: DefId,
args: GenericArgsRef<'tcx>,
) -> Ty<'tcx> {
Ty::new(tcx, CoroutineWitness(id, args))
}
// misc
#[inline]
pub fn new_unit(tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
tcx.types.unit
}
#[inline]
pub fn new_static_str(tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
Ty::new_imm_ref(tcx, tcx.lifetimes.re_static, tcx.types.str_)
}
#[inline]
pub fn new_diverging_default(tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
if tcx.features().never_type_fallback { tcx.types.never } else { tcx.types.unit }
}
// lang and diagnostic tys
fn new_generic_adt(tcx: TyCtxt<'tcx>, wrapper_def_id: DefId, ty_param: Ty<'tcx>) -> Ty<'tcx> {
let adt_def = tcx.adt_def(wrapper_def_id);
let args = GenericArgs::for_item(tcx, wrapper_def_id, |param, args| match param.kind {
GenericParamDefKind::Lifetime | GenericParamDefKind::Const { .. } => bug!(),
GenericParamDefKind::Type { has_default, .. } => {
if param.index == 0 {
ty_param.into()
} else {
assert!(has_default);
tcx.type_of(param.def_id).instantiate(tcx, args).into()
}
}
});
Ty::new(tcx, Adt(adt_def, args))
}
#[inline]
pub fn new_lang_item(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, item: LangItem) -> Option<Ty<'tcx>> {
let def_id = tcx.lang_items().get(item)?;
Some(Ty::new_generic_adt(tcx, def_id, ty))
}
#[inline]
pub fn new_diagnostic_item(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>, name: Symbol) -> Option<Ty<'tcx>> {
let def_id = tcx.get_diagnostic_item(name)?;
Some(Ty::new_generic_adt(tcx, def_id, ty))
}
#[inline]
pub fn new_box(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
let def_id = tcx.require_lang_item(LangItem::OwnedBox, None);
Ty::new_generic_adt(tcx, def_id, ty)
}
#[inline]
pub fn new_maybe_uninit(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> Ty<'tcx> {
let def_id = tcx.require_lang_item(LangItem::MaybeUninit, None);
Ty::new_generic_adt(tcx, def_id, ty)
}
/// Creates a `&mut Context<'_>` [`Ty`] with erased lifetimes.
pub fn new_task_context(tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
let context_did = tcx.require_lang_item(LangItem::Context, None);
let context_adt_ref = tcx.adt_def(context_did);
let context_args = tcx.mk_args(&[tcx.lifetimes.re_erased.into()]);
let context_ty = Ty::new_adt(tcx, context_adt_ref, context_args);
Ty::new_mut_ref(tcx, tcx.lifetimes.re_erased, context_ty)
}
}
impl<'tcx> rustc_type_ir::new::Ty<TyCtxt<'tcx>> for Ty<'tcx> {
fn new_anon_bound(tcx: TyCtxt<'tcx>, debruijn: ty::DebruijnIndex, var: ty::BoundVar) -> Self {
Ty::new_bound(tcx, debruijn, ty::BoundTy { var, kind: ty::BoundTyKind::Anon })
}
}
/// Type utilities
impl<'tcx> Ty<'tcx> {
#[inline(always)]
pub fn kind(self) -> &'tcx TyKind<'tcx> {
self.0.0
}
// FIXME(compiler-errors): Think about removing this.
#[inline(always)]
pub fn flags(self) -> TypeFlags {
self.0.0.flags
}
#[inline]
pub fn is_unit(self) -> bool {
match self.kind() {
Tuple(tys) => tys.is_empty(),
_ => false,
}
}
#[inline]
pub fn is_never(self) -> bool {
matches!(self.kind(), Never)
}
#[inline]
pub fn is_primitive(self) -> bool {
self.kind().is_primitive()
}
#[inline]
pub fn is_adt(self) -> bool {
matches!(self.kind(), Adt(..))
}
#[inline]
pub fn is_ref(self) -> bool {
matches!(self.kind(), Ref(..))
}
#[inline]
pub fn is_ty_var(self) -> bool {
matches!(self.kind(), Infer(TyVar(_)))
}
#[inline]
pub fn ty_vid(self) -> Option<ty::TyVid> {
match self.kind() {
&Infer(TyVar(vid)) => Some(vid),
_ => None,
}
}
#[inline]
pub fn is_ty_or_numeric_infer(self) -> bool {
matches!(self.kind(), Infer(_))
}
#[inline]
pub fn is_phantom_data(self) -> bool {
if let Adt(def, _) = self.kind() { def.is_phantom_data() } else { false }
}
#[inline]
pub fn is_bool(self) -> bool {
*self.kind() == Bool
}
/// Returns `true` if this type is a `str`.
#[inline]
pub fn is_str(self) -> bool {
*self.kind() == Str
}
#[inline]
pub fn is_param(self, index: u32) -> bool {
match self.kind() {
ty::Param(ref data) => data.index == index,
_ => false,
}
}
#[inline]
pub fn is_slice(self) -> bool {
matches!(self.kind(), Slice(_))
}
#[inline]
pub fn is_array_slice(self) -> bool {
match self.kind() {
Slice(_) => true,
RawPtr(TypeAndMut { ty, .. }) | Ref(_, ty, _) => matches!(ty.kind(), Slice(_)),
_ => false,
}
}
#[inline]
pub fn is_array(self) -> bool {
matches!(self.kind(), Array(..))
}
#[inline]
pub fn is_simd(self) -> bool {
match self.kind() {
Adt(def, _) => def.repr().simd(),
_ => false,
}
}
pub fn sequence_element_type(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
match self.kind() {
Array(ty, _) | Slice(ty) => *ty,
Str => tcx.types.u8,
_ => bug!("`sequence_element_type` called on non-sequence value: {}", self),
}
}
pub fn simd_size_and_type(self, tcx: TyCtxt<'tcx>) -> (u64, Ty<'tcx>) {
match self.kind() {
Adt(def, args) => {
assert!(def.repr().simd(), "`simd_size_and_type` called on non-SIMD type");
let variant = def.non_enum_variant();
let f0_ty = variant.fields[FieldIdx::from_u32(0)].ty(tcx, args);
match f0_ty.kind() {
// If the first field is an array, we assume it is the only field and its
// elements are the SIMD components.
Array(f0_elem_ty, f0_len) => {
// FIXME(repr_simd): https://github.com/rust-lang/rust/pull/78863#discussion_r522784112
// The way we evaluate the `N` in `[T; N]` here only works since we use
// `simd_size_and_type` post-monomorphization. It will probably start to ICE
// if we use it in generic code. See the `simd-array-trait` ui test.
(f0_len.eval_target_usize(tcx, ParamEnv::empty()), *f0_elem_ty)
}
// Otherwise, the fields of this Adt are the SIMD components (and we assume they
// all have the same type).
_ => (variant.fields.len() as u64, f0_ty),
}
}
_ => bug!("`simd_size_and_type` called on invalid type"),
}
}
#[inline]
pub fn is_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_ref() || self.is_unsafe_ptr() || self.is_fn_ptr()
}
#[inline]
pub fn is_box(self) -> bool {
match self.kind() {
Adt(def, _) => def.is_box(),
_ => false,
}
}
/// Tests whether this is a Box using the global allocator.
#[inline]
pub fn is_box_global(self, tcx: TyCtxt<'tcx>) -> bool {
match self.kind() {
Adt(def, args) if def.is_box() => {
let Some(alloc) = args.get(1) else {
// Single-argument Box is always global. (for "minicore" tests)
return true;
};
alloc.expect_ty().ty_adt_def().is_some_and(|alloc_adt| {
let global_alloc = tcx.require_lang_item(LangItem::GlobalAlloc, None);
alloc_adt.did() == global_alloc
})
}
_ => false,
}
}
/// Panics if called on any type other than `Box<T>`.
pub fn boxed_ty(self) -> Ty<'tcx> {
match self.kind() {
Adt(def, args) if def.is_box() => args.type_at(0),
_ => bug!("`boxed_ty` is called on non-box type {:?}", self),
}
}
/// A scalar type is one that denotes an atomic datum, with no sub-components.
/// (A RawPtr is scalar because it represents a non-managed pointer, so its
/// contents are abstract to rustc.)
#[inline]
pub fn is_scalar(self) -> bool {
matches!(
self.kind(),
Bool | Char
| Int(_)
| Float(_)
| Uint(_)
| FnDef(..)
| FnPtr(_)
| RawPtr(_)
| Infer(IntVar(_) | FloatVar(_))
)
}
/// Returns `true` if this type is a floating point type.
#[inline]
pub fn is_floating_point(self) -> bool {
matches!(self.kind(), Float(_) | Infer(FloatVar(_)))
}
#[inline]
pub fn is_trait(self) -> bool {
matches!(self.kind(), Dynamic(_, _, ty::Dyn))
}
#[inline]
pub fn is_dyn_star(self) -> bool {
matches!(self.kind(), Dynamic(_, _, ty::DynStar))
}
#[inline]
pub fn is_enum(self) -> bool {
matches!(self.kind(), Adt(adt_def, _) if adt_def.is_enum())
}
#[inline]
pub fn is_union(self) -> bool {
matches!(self.kind(), Adt(adt_def, _) if adt_def.is_union())
}
#[inline]
pub fn is_closure(self) -> bool {
matches!(self.kind(), Closure(..))
}
#[inline]
pub fn is_coroutine(self) -> bool {
matches!(self.kind(), Coroutine(..))
}
#[inline]
pub fn is_coroutine_closure(self) -> bool {
matches!(self.kind(), CoroutineClosure(..))
}
#[inline]
pub fn is_integral(self) -> bool {
matches!(self.kind(), Infer(IntVar(_)) | Int(_) | Uint(_))
}
#[inline]
pub fn is_fresh_ty(self) -> bool {
matches!(self.kind(), Infer(FreshTy(_)))
}
#[inline]
pub fn is_fresh(self) -> bool {
matches!(self.kind(), Infer(FreshTy(_) | FreshIntTy(_) | FreshFloatTy(_)))
}
#[inline]
pub fn is_char(self) -> bool {
matches!(self.kind(), Char)
}
#[inline]
pub fn is_numeric(self) -> bool {
self.is_integral() || self.is_floating_point()
}
#[inline]
pub fn is_signed(self) -> bool {
matches!(self.kind(), Int(_))
}
#[inline]
pub fn is_ptr_sized_integral(self) -> bool {
matches!(self.kind(), Int(ty::IntTy::Isize) | Uint(ty::UintTy::Usize))
}
#[inline]
pub fn has_concrete_skeleton(self) -> bool {
!matches!(self.kind(), Param(_) | Infer(_) | Error(_))
}
/// Checks whether a type recursively contains another type
///
/// Example: `Option<()>` contains `()`
pub fn contains(self, other: Ty<'tcx>) -> bool {
struct ContainsTyVisitor<'tcx>(Ty<'tcx>);
impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ContainsTyVisitor<'tcx> {
type Result = ControlFlow<()>;
fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
if self.0 == t { ControlFlow::Break(()) } else { t.super_visit_with(self) }
}
}
let cf = self.visit_with(&mut ContainsTyVisitor(other));
cf.is_break()
}
/// Checks whether a type recursively contains any closure
///
/// Example: `Option<{closure@file.rs:4:20}>` returns true
pub fn contains_closure(self) -> bool {
struct ContainsClosureVisitor;
impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ContainsClosureVisitor {
type Result = ControlFlow<()>;
fn visit_ty(&mut self, t: Ty<'tcx>) -> Self::Result {
if let ty::Closure(..) = t.kind() {
ControlFlow::Break(())
} else {
t.super_visit_with(self)
}
}
}
let cf = self.visit_with(&mut ContainsClosureVisitor);
cf.is_break()
}
/// Returns the type and mutability of `*ty`.
///
/// The parameter `explicit` indicates if this is an *explicit* dereference.
/// Some types -- notably unsafe ptrs -- can only be dereferenced explicitly.
pub fn builtin_deref(self, explicit: bool) -> Option<TypeAndMut<'tcx>> {
match self.kind() {
Adt(def, _) if def.is_box() => {
Some(TypeAndMut { ty: self.boxed_ty(), mutbl: hir::Mutability::Not })
}
Ref(_, ty, mutbl) => Some(TypeAndMut { ty: *ty, mutbl: *mutbl }),
RawPtr(mt) if explicit => Some(*mt),
_ => None,
}
}
/// Returns the type of `ty[i]`.
pub fn builtin_index(self) -> Option<Ty<'tcx>> {
match self.kind() {
Array(ty, _) | Slice(ty) => Some(*ty),
_ => None,
}
}
pub fn fn_sig(self, tcx: TyCtxt<'tcx>) -> PolyFnSig<'tcx> {
match self.kind() {
FnDef(def_id, args) => tcx.fn_sig(*def_id).instantiate(tcx, args),
FnPtr(f) => *f,
Error(_) => {
// ignore errors (#54954)
ty::Binder::dummy(FnSig::fake())
}
Closure(..) => bug!(
"to get the signature of a closure, use `args.as_closure().sig()` not `fn_sig()`",
),
_ => bug!("Ty::fn_sig() called on non-fn type: {:?}", self),
}
}
#[inline]
pub fn is_fn(self) -> bool {
matches!(self.kind(), FnDef(..) | FnPtr(_))
}
#[inline]
pub fn is_fn_ptr(self) -> bool {
matches!(self.kind(), FnPtr(_))
}
#[inline]
pub fn is_impl_trait(self) -> bool {
matches!(self.kind(), Alias(ty::Opaque, ..))
}
#[inline]
pub fn ty_adt_def(self) -> Option<AdtDef<'tcx>> {
match self.kind() {
Adt(adt, _) => Some(*adt),
_ => None,
}
}
/// Iterates over tuple fields.
/// Panics when called on anything but a tuple.
#[inline]
pub fn tuple_fields(self) -> &'tcx List<Ty<'tcx>> {
match self.kind() {
Tuple(args) => args,
_ => 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 coroutines.
#[inline]
pub fn variant_range(self, tcx: TyCtxt<'tcx>) -> Option<Range<VariantIdx>> {
match self.kind() {
TyKind::Adt(adt, _) => Some(adt.variant_range()),
TyKind::Coroutine(def_id, args) => {
Some(args.as_coroutine().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 coroutines.
#[inline]
pub fn discriminant_for_variant(
self,
tcx: TyCtxt<'tcx>,
variant_index: VariantIdx,
) -> Option<Discr<'tcx>> {
match self.kind() {
TyKind::Adt(adt, _) if adt.is_enum() => {
Some(adt.discriminant_for_variant(tcx, variant_index))
}
TyKind::Coroutine(def_id, args) => {
Some(args.as_coroutine().discriminant_for_variant(*def_id, tcx, variant_index))
}
_ => None,
}
}
/// Returns the type of the discriminant of this type.
pub fn discriminant_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
match self.kind() {
ty::Adt(adt, _) if adt.is_enum() => adt.repr().discr_type().to_ty(tcx),
ty::Coroutine(_, args) => args.as_coroutine().discr_ty(tcx),
ty::Param(_) | ty::Alias(..) | ty::Infer(ty::TyVar(_)) => {
let assoc_items = tcx.associated_item_def_ids(
tcx.require_lang_item(hir::LangItem::DiscriminantKind, None),
);
Ty::new_projection(tcx, assoc_items[0], tcx.mk_args(&[self.into()]))
}
ty::Bool
| ty::Char
| ty::Int(_)
| ty::Uint(_)
| ty::Float(_)
| ty::Adt(..)
| ty::Foreign(_)
| ty::Str
| ty::Array(..)
| ty::Slice(_)
| ty::RawPtr(_)
| ty::Ref(..)
| ty::FnDef(..)
| ty::FnPtr(..)
| ty::Dynamic(..)
| ty::Closure(..)
| ty::CoroutineClosure(..)
| ty::CoroutineWitness(..)
| 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,
/// or the struct tail if the metadata type cannot be determined.
pub fn ptr_metadata_ty_or_tail(
self,
tcx: TyCtxt<'tcx>,
normalize: impl FnMut(Ty<'tcx>) -> Ty<'tcx>,
) -> Result<Ty<'tcx>, Ty<'tcx>> {
let tail = tcx.struct_tail_with_normalize(self, normalize, || {});
match tail.kind() {
// Sized types
ty::Infer(ty::IntVar(_) | ty::FloatVar(_))
| ty::Uint(_)
| ty::Int(_)
| ty::Bool
| ty::Float(_)
| ty::FnDef(..)
| ty::FnPtr(_)
| ty::RawPtr(..)
| ty::Char
| ty::Ref(..)
| ty::Coroutine(..)
| ty::CoroutineWitness(..)
| ty::Array(..)
| ty::Closure(..)
| ty::CoroutineClosure(..)
| ty::Never
| ty::Error(_)
// Extern types have metadata = ().
| ty::Foreign(..)
// `dyn*` has metadata = ().
| ty::Dynamic(_, _, ty::DynStar)
// If returned by `struct_tail_with_normalize` this is a unit struct
// without any fields, or not a struct, and therefore is Sized.
| ty::Adt(..)
// If returned by `struct_tail_with_normalize` this is the empty tuple,
// a.k.a. unit type, which is Sized
| ty::Tuple(..) => Ok(tcx.types.unit),
ty::Str | ty::Slice(_) => Ok(tcx.types.usize),
ty::Dynamic(_, _, ty::Dyn) => {
let dyn_metadata = tcx.require_lang_item(LangItem::DynMetadata, None);
Ok(tcx.type_of(dyn_metadata).instantiate(tcx, &[tail.into()]))
}
// We don't know the metadata of `self`, but it must be equal to the
// metadata of `tail`.
ty::Param(_) | ty::Alias(..) => Err(tail),
ty::Infer(ty::TyVar(_))
| ty::Bound(..)
| ty::Placeholder(..)
| ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => bug!(
"`ptr_metadata_ty_or_tail` applied to unexpected type: {self:?} (tail = {tail:?})"
),
}
}
/// Returns the type of metadata for (potentially fat) pointers to this type.
/// Causes an ICE if the metadata type cannot be determined.
pub fn ptr_metadata_ty(
self,
tcx: TyCtxt<'tcx>,
normalize: impl FnMut(Ty<'tcx>) -> Ty<'tcx>,
) -> Ty<'tcx> {
match self.ptr_metadata_ty_or_tail(tcx, normalize) {
Ok(metadata) => metadata,
Err(tail) => bug!(
"`ptr_metadata_ty` failed to get metadata for type: {self:?} (tail = {tail:?})"
),
}
}
/// When we create a closure, we record its kind (i.e., what trait
/// it implements, constrained by how it uses its borrows) into its
/// [`ty::ClosureArgs`] or [`ty::CoroutineClosureArgs`] 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 [`Ty::from_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 `rustc_hir_analysis/src/check/upvar.rs`)
/// is complete, that type variable will be unified with one of
/// the integral types.
///
/// ```rust,ignore (snippet of compiler code)
/// if let TyKind::Closure(def_id, args) = closure_ty.kind()
/// && let Some(closure_kind) = args.as_closure().kind_ty().to_opt_closure_kind()
/// {
/// println!("{closure_kind:?}");
/// } else if let TyKind::CoroutineClosure(def_id, args) = closure_ty.kind()
/// && let Some(closure_kind) = args.as_coroutine_closure().kind_ty().to_opt_closure_kind()
/// {
/// println!("{closure_kind:?}");
/// }
/// ```
///
/// After upvar analysis, you should instead use [`ClosureArgs::kind()`]
/// or [`CoroutineClosureArgs::kind()`] to assert that the `ClosureKind`
/// has been constrained instead of manually calling this method.
///
/// ```rust,ignore (snippet of compiler code)
/// if let TyKind::Closure(def_id, args) = closure_ty.kind()
/// {
/// println!("{:?}", args.as_closure().kind());
/// } else if let TyKind::CoroutineClosure(def_id, args) = closure_ty.kind()
/// {
/// println!("{:?}", args.as_coroutine_closure().kind());
/// }
/// ```
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, and `Placeholder` and `Param`
// may be encountered in generic `AsyncFnKindHelper` goals.
Bound(..) | Placeholder(_) | Param(_) | Infer(_) => None,
Error(_) => Some(ty::ClosureKind::Fn),
_ => bug!("cannot convert type `{:?}` to a closure kind", self),
}
}
/// Inverse of [`Ty::to_opt_closure_kind`]. See docs on that method
/// for explanation of the relationship between `Ty` and [`ty::ClosureKind`].
pub fn from_closure_kind(tcx: TyCtxt<'tcx>, kind: ty::ClosureKind) -> Ty<'tcx> {
match kind {
ty::ClosureKind::Fn => tcx.types.i8,
ty::ClosureKind::FnMut => tcx.types.i16,
ty::ClosureKind::FnOnce => tcx.types.i32,
}
}
/// Like [`Ty::to_opt_closure_kind`], but it caps the "maximum" closure kind
/// to `FnMut`. This is because although we have three capability states,
/// `AsyncFn`/`AsyncFnMut`/`AsyncFnOnce`, we only need to distinguish two coroutine
/// bodies: by-ref and by-value.
///
/// See the definition of `AsyncFn` and `AsyncFnMut` and the `CallRefFuture`
/// associated type for why we don't distinguish [`ty::ClosureKind::Fn`] and
/// [`ty::ClosureKind::FnMut`] for the purpose of the generated MIR bodies.
///
/// This method should be used when constructing a `Coroutine` out of a
/// `CoroutineClosure`, when the `Coroutine`'s `kind` field is being populated
/// directly from the `CoroutineClosure`'s `kind`.
pub fn from_coroutine_closure_kind(tcx: TyCtxt<'tcx>, kind: ty::ClosureKind) -> Ty<'tcx> {
match kind {
ty::ClosureKind::Fn | ty::ClosureKind::FnMut => tcx.types.i16,
ty::ClosureKind::FnOnce => tcx.types.i32,
}
}
/// 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::Coroutine(..)
| ty::CoroutineWitness(..)
| ty::Array(..)
| ty::Closure(..)
| ty::CoroutineClosure(..)
| ty::Never
| ty::Error(_)
| ty::Dynamic(_, _, ty::DynStar) => true,
ty::Str | ty::Slice(_) | ty::Dynamic(_, _, ty::Dyn) | ty::Foreign(..) => false,
ty::Tuple(tys) => tys.last().map_or(true, |ty| ty.is_trivially_sized(tcx)),
ty::Adt(def, args) => def
.sized_constraint(tcx)
.map_or(true, |ty| ty.instantiate(tcx, args).is_trivially_sized(tcx)),
ty::Alias(..) | ty::Param(_) | ty::Placeholder(..) | ty::Bound(..) => false,
ty::Infer(ty::TyVar(_)) => false,
ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => {
bug!("`is_trivially_sized` applied to unexpected type: {:?}", self)
}
}
}
/// Fast path helper for primitives which are always `Copy` and which
/// have a side-effect-free `Clone` impl.
///
/// Returning true means the type is known to be pure and `Copy+Clone`.
/// Returning `false` means nothing -- could be `Copy`, might not be.
///
/// This is mostly useful for optimizations, as these are the types
/// on which we can replace cloning with dereferencing.
pub fn is_trivially_pure_clone_copy(self) -> bool {
match self.kind() {
ty::Bool | ty::Char | ty::Never => true,
// These aren't even `Clone`
ty::Str | ty::Slice(..) | ty::Foreign(..) | ty::Dynamic(..) => false,
ty::Infer(ty::InferTy::FloatVar(_) | ty::InferTy::IntVar(_))
| ty::Int(..)
| ty::Uint(..)
| ty::Float(..) => true,
// ZST which can't be named are fine.
ty::FnDef(..) => true,
ty::Array(element_ty, _len) => element_ty.is_trivially_pure_clone_copy(),
// A 100-tuple isn't "trivial", so doing this only for reasonable sizes.
ty::Tuple(field_tys) => {
field_tys.len() <= 3 && field_tys.iter().all(Self::is_trivially_pure_clone_copy)
}
// Sometimes traits aren't implemented for every ABI or arity,
// because we can't be generic over everything yet.
ty::FnPtr(..) => false,
// Definitely absolutely not copy.
ty::Ref(_, _, hir::Mutability::Mut) => false,
// Thin pointers & thin shared references are pure-clone-copy, but for
// anything with custom metadata it might be more complicated.
ty::Ref(_, _, hir::Mutability::Not) | ty::RawPtr(..) => false,
ty::Coroutine(..) | ty::CoroutineWitness(..) => false,
// Might be, but not "trivial" so just giving the safe answer.
ty::Adt(..) | ty::Closure(..) | ty::CoroutineClosure(..) => false,
// Needs normalization or revealing to determine, so no is the safe answer.
ty::Alias(..) => false,
ty::Param(..) | ty::Infer(..) | ty::Error(..) => false,
ty::Bound(..) | ty::Placeholder(..) => {
bug!("`is_trivially_pure_clone_copy` applied to unexpected type: {:?}", self);
}
}
}
/// If `self` is a primitive, return its [`Symbol`].
pub fn primitive_symbol(self) -> Option<Symbol> {
match self.kind() {
ty::Bool => Some(sym::bool),
ty::Char => Some(sym::char),
ty::Float(f) => match f {
ty::FloatTy::F16 => Some(sym::f16),
ty::FloatTy::F32 => Some(sym::f32),
ty::FloatTy::F64 => Some(sym::f64),
ty::FloatTy::F128 => Some(sym::f128),
},
ty::Int(f) => match f {
ty::IntTy::Isize => Some(sym::isize),
ty::IntTy::I8 => Some(sym::i8),
ty::IntTy::I16 => Some(sym::i16),
ty::IntTy::I32 => Some(sym::i32),
ty::IntTy::I64 => Some(sym::i64),
ty::IntTy::I128 => Some(sym::i128),
},
ty::Uint(f) => match f {
ty::UintTy::Usize => Some(sym::usize),
ty::UintTy::U8 => Some(sym::u8),
ty::UintTy::U16 => Some(sym::u16),
ty::UintTy::U32 => Some(sym::u32),
ty::UintTy::U64 => Some(sym::u64),
ty::UintTy::U128 => Some(sym::u128),
},
_ => None,
}
}
pub fn is_c_void(self, tcx: TyCtxt<'_>) -> bool {
match self.kind() {
ty::Adt(adt, _) => tcx.lang_items().get(LangItem::CVoid) == Some(adt.did()),
_ => false,
}
}
/// Returns `true` when the outermost type cannot be further normalized,
/// resolved, or instantiated. This includes all primitive types, but also
/// things like ADTs and trait objects, sice even if their arguments or
/// nested types may be further simplified, the outermost [`TyKind`] or
/// type constructor remains the same.
pub fn is_known_rigid(self) -> bool {
match self.kind() {
Bool
| Char
| Int(_)
| Uint(_)
| Float(_)
| Adt(_, _)
| Foreign(_)
| Str
| Array(_, _)
| Slice(_)
| RawPtr(_)
| Ref(_, _, _)
| FnDef(_, _)
| FnPtr(_)
| Dynamic(_, _, _)
| Closure(_, _)
| CoroutineClosure(_, _)
| Coroutine(_, _)
| CoroutineWitness(..)
| Never
| Tuple(_) => true,
Error(_) | Infer(_) | Alias(_, _) | Param(_) | Bound(_, _) | Placeholder(_) => false,
}
}
}
/// Extra information about why we ended up with a particular variance.
/// This is only used to add more information to error messages, and
/// has no effect on soundness. While choosing the 'wrong' `VarianceDiagInfo`
/// may lead to confusing notes in error messages, it will never cause
/// a miscompilation or unsoundness.
///
/// When in doubt, use `VarianceDiagInfo::default()`
#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, PartialOrd, Ord)]
pub enum VarianceDiagInfo<'tcx> {
/// No additional information - this is the default.
/// We will not add any additional information to error messages.
#[default]
None,
/// We switched our variance because a generic argument occurs inside
/// the invariant generic argument of another type.
Invariant {
/// The generic type containing the generic parameter
/// that changes the variance (e.g. `*mut T`, `MyStruct<T>`)
ty: Ty<'tcx>,
/// The index of the generic parameter being used
/// (e.g. `0` for `*mut T`, `1` for `MyStruct<'CovariantParam, 'InvariantParam>`)
param_index: u32,
},
}
impl<'tcx> VarianceDiagInfo<'tcx> {
/// Mirrors `Variance::xform` - used to 'combine' the existing
/// and new `VarianceDiagInfo`s when our variance changes.
pub fn xform(self, other: VarianceDiagInfo<'tcx>) -> VarianceDiagInfo<'tcx> {
// For now, just use the first `VarianceDiagInfo::Invariant` that we see
match self {
VarianceDiagInfo::None => other,
VarianceDiagInfo::Invariant { .. } => self,
}
}
}
// Some types are used a lot. Make sure they don't unintentionally get bigger.
#[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
mod size_asserts {
use super::*;
use rustc_data_structures::static_assert_size;
// tidy-alphabetical-start
static_assert_size!(ty::RegionKind<'_>, 24);
static_assert_size!(ty::TyKind<'_>, 32);
// tidy-alphabetical-end
}