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//! Generalized type relating mechanism.
//!
//! A type relation `R` relates a pair of values `(A, B)`. `A and B` are usually
//! types or regions but can be other things. Examples of type relations are
//! subtyping, type equality, etc.
use crate::hir::def_id::DefId;
use crate::ty::subst::{Kind, UnpackedKind, SubstsRef};
use crate::ty::{self, Ty, TyCtxt, TypeFoldable};
use crate::ty::error::{ExpectedFound, TypeError};
use crate::mir::interpret::{ConstValue, Scalar, GlobalId};
use std::rc::Rc;
use std::iter;
use rustc_target::spec::abi;
use crate::hir as ast;
use crate::traits;
pub type RelateResult<'tcx, T> = Result<T, TypeError<'tcx>>;
#[derive(Clone, Debug)]
pub enum Cause {
ExistentialRegionBound, // relating an existential region bound
}
pub trait TypeRelation<'tcx>: Sized {
fn tcx(&self) -> TyCtxt<'tcx>;
/// Returns a static string we can use for printouts.
fn tag(&self) -> &'static str;
/// Returns `true` if the value `a` is the "expected" type in the
/// relation. Just affects error messages.
fn a_is_expected(&self) -> bool;
fn with_cause<F,R>(&mut self, _cause: Cause, f: F) -> R
where F: FnOnce(&mut Self) -> R
{
f(self)
}
/// Generic relation routine suitable for most anything.
fn relate<T: Relate<'tcx>>(&mut self, a: &T, b: &T) -> RelateResult<'tcx, T> {
Relate::relate(self, a, b)
}
/// Relate the two substitutions for the given item. The default
/// is to look up the variance for the item and proceed
/// accordingly.
fn relate_item_substs(&mut self,
item_def_id: DefId,
a_subst: SubstsRef<'tcx>,
b_subst: SubstsRef<'tcx>)
-> RelateResult<'tcx, SubstsRef<'tcx>>
{
debug!("relate_item_substs(item_def_id={:?}, a_subst={:?}, b_subst={:?})",
item_def_id,
a_subst,
b_subst);
let opt_variances = self.tcx().variances_of(item_def_id);
relate_substs(self, Some(opt_variances), a_subst, b_subst)
}
/// Switch variance for the purpose of relating `a` and `b`.
fn relate_with_variance<T: Relate<'tcx>>(&mut self,
variance: ty::Variance,
a: &T,
b: &T)
-> RelateResult<'tcx, T>;
// Overrideable relations. You shouldn't typically call these
// directly, instead call `relate()`, which in turn calls
// these. This is both more uniform but also allows us to add
// additional hooks for other types in the future if needed
// without making older code, which called `relate`, obsolete.
fn tys(&mut self, a: Ty<'tcx>, b: Ty<'tcx>) -> RelateResult<'tcx, Ty<'tcx>>;
fn regions(
&mut self,
a: ty::Region<'tcx>,
b: ty::Region<'tcx>
) -> RelateResult<'tcx, ty::Region<'tcx>>;
fn consts(
&mut self,
a: &'tcx ty::Const<'tcx>,
b: &'tcx ty::Const<'tcx>
) -> RelateResult<'tcx, &'tcx ty::Const<'tcx>>;
fn binders<T>(&mut self, a: &ty::Binder<T>, b: &ty::Binder<T>)
-> RelateResult<'tcx, ty::Binder<T>>
where T: Relate<'tcx>;
}
pub trait Relate<'tcx>: TypeFoldable<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &Self,
b: &Self,
) -> RelateResult<'tcx, Self>;
}
///////////////////////////////////////////////////////////////////////////
// Relate impls
impl<'tcx> Relate<'tcx> for ty::TypeAndMut<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::TypeAndMut<'tcx>,
b: &ty::TypeAndMut<'tcx>,
) -> RelateResult<'tcx, ty::TypeAndMut<'tcx>> {
debug!("{}.mts({:?}, {:?})",
relation.tag(),
a,
b);
if a.mutbl != b.mutbl {
Err(TypeError::Mutability)
} else {
let mutbl = a.mutbl;
let variance = match mutbl {
ast::Mutability::MutImmutable => ty::Covariant,
ast::Mutability::MutMutable => ty::Invariant,
};
let ty = relation.relate_with_variance(variance, &a.ty, &b.ty)?;
Ok(ty::TypeAndMut { ty, mutbl })
}
}
}
pub fn relate_substs<R: TypeRelation<'tcx>>(
relation: &mut R,
variances: Option<&[ty::Variance]>,
a_subst: SubstsRef<'tcx>,
b_subst: SubstsRef<'tcx>,
) -> RelateResult<'tcx, SubstsRef<'tcx>> {
let tcx = relation.tcx();
let params = a_subst.iter().zip(b_subst).enumerate().map(|(i, (a, b))| {
let variance = variances.map_or(ty::Invariant, |v| v[i]);
relation.relate_with_variance(variance, a, b)
});
Ok(tcx.mk_substs(params)?)
}
impl<'tcx> Relate<'tcx> for ty::FnSig<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::FnSig<'tcx>,
b: &ty::FnSig<'tcx>,
) -> RelateResult<'tcx, ty::FnSig<'tcx>> {
let tcx = relation.tcx();
if a.c_variadic != b.c_variadic {
return Err(TypeError::VariadicMismatch(
expected_found(relation, &a.c_variadic, &b.c_variadic)));
}
let unsafety = relation.relate(&a.unsafety, &b.unsafety)?;
let abi = relation.relate(&a.abi, &b.abi)?;
if a.inputs().len() != b.inputs().len() {
return Err(TypeError::ArgCount);
}
let inputs_and_output = a.inputs().iter().cloned()
.zip(b.inputs().iter().cloned())
.map(|x| (x, false))
.chain(iter::once(((a.output(), b.output()), true)))
.map(|((a, b), is_output)| {
if is_output {
relation.relate(&a, &b)
} else {
relation.relate_with_variance(ty::Contravariant, &a, &b)
}
});
Ok(ty::FnSig {
inputs_and_output: tcx.mk_type_list(inputs_and_output)?,
c_variadic: a.c_variadic,
unsafety,
abi,
})
}
}
impl<'tcx> Relate<'tcx> for ast::Unsafety {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ast::Unsafety,
b: &ast::Unsafety,
) -> RelateResult<'tcx, ast::Unsafety> {
if a != b {
Err(TypeError::UnsafetyMismatch(expected_found(relation, a, b)))
} else {
Ok(*a)
}
}
}
impl<'tcx> Relate<'tcx> for abi::Abi {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &abi::Abi,
b: &abi::Abi,
) -> RelateResult<'tcx, abi::Abi> {
if a == b {
Ok(*a)
} else {
Err(TypeError::AbiMismatch(expected_found(relation, a, b)))
}
}
}
impl<'tcx> Relate<'tcx> for ty::ProjectionTy<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::ProjectionTy<'tcx>,
b: &ty::ProjectionTy<'tcx>,
) -> RelateResult<'tcx, ty::ProjectionTy<'tcx>> {
if a.item_def_id != b.item_def_id {
Err(TypeError::ProjectionMismatched(
expected_found(relation, &a.item_def_id, &b.item_def_id)))
} else {
let substs = relation.relate(&a.substs, &b.substs)?;
Ok(ty::ProjectionTy {
item_def_id: a.item_def_id,
substs: &substs,
})
}
}
}
impl<'tcx> Relate<'tcx> for ty::ExistentialProjection<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::ExistentialProjection<'tcx>,
b: &ty::ExistentialProjection<'tcx>,
) -> RelateResult<'tcx, ty::ExistentialProjection<'tcx>> {
if a.item_def_id != b.item_def_id {
Err(TypeError::ProjectionMismatched(
expected_found(relation, &a.item_def_id, &b.item_def_id)))
} else {
let ty = relation.relate(&a.ty, &b.ty)?;
let substs = relation.relate(&a.substs, &b.substs)?;
Ok(ty::ExistentialProjection {
item_def_id: a.item_def_id,
substs,
ty,
})
}
}
}
impl<'tcx> Relate<'tcx> for Vec<ty::PolyExistentialProjection<'tcx>> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &Vec<ty::PolyExistentialProjection<'tcx>>,
b: &Vec<ty::PolyExistentialProjection<'tcx>>,
) -> RelateResult<'tcx, Vec<ty::PolyExistentialProjection<'tcx>>> {
// To be compatible, `a` and `b` must be for precisely the
// same set of traits and item names. We always require that
// projection bounds lists are sorted by trait-def-id and item-name,
// so we can just iterate through the lists pairwise, so long as they are the
// same length.
if a.len() != b.len() {
Err(TypeError::ProjectionBoundsLength(expected_found(relation, &a.len(), &b.len())))
} else {
a.iter()
.zip(b)
.map(|(a, b)| relation.relate(a, b))
.collect()
}
}
}
impl<'tcx> Relate<'tcx> for ty::TraitRef<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::TraitRef<'tcx>,
b: &ty::TraitRef<'tcx>,
) -> RelateResult<'tcx, ty::TraitRef<'tcx>> {
// Different traits cannot be related
if a.def_id != b.def_id {
Err(TypeError::Traits(expected_found(relation, &a.def_id, &b.def_id)))
} else {
let substs = relate_substs(relation, None, a.substs, b.substs)?;
Ok(ty::TraitRef { def_id: a.def_id, substs: substs })
}
}
}
impl<'tcx> Relate<'tcx> for ty::ExistentialTraitRef<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::ExistentialTraitRef<'tcx>,
b: &ty::ExistentialTraitRef<'tcx>,
) -> RelateResult<'tcx, ty::ExistentialTraitRef<'tcx>> {
// Different traits cannot be related
if a.def_id != b.def_id {
Err(TypeError::Traits(expected_found(relation, &a.def_id, &b.def_id)))
} else {
let substs = relate_substs(relation, None, a.substs, b.substs)?;
Ok(ty::ExistentialTraitRef { def_id: a.def_id, substs: substs })
}
}
}
#[derive(Debug, Clone)]
struct GeneratorWitness<'tcx>(&'tcx ty::List<Ty<'tcx>>);
TupleStructTypeFoldableImpl! {
impl<'tcx> TypeFoldable<'tcx> for GeneratorWitness<'tcx> {
a
}
}
impl<'tcx> Relate<'tcx> for GeneratorWitness<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &GeneratorWitness<'tcx>,
b: &GeneratorWitness<'tcx>,
) -> RelateResult<'tcx, GeneratorWitness<'tcx>> {
assert_eq!(a.0.len(), b.0.len());
let tcx = relation.tcx();
let types = tcx.mk_type_list(a.0.iter().zip(b.0).map(|(a, b)| relation.relate(a, b)))?;
Ok(GeneratorWitness(types))
}
}
impl<'tcx> Relate<'tcx> for Ty<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &Ty<'tcx>,
b: &Ty<'tcx>,
) -> RelateResult<'tcx, Ty<'tcx>> {
relation.tys(a, b)
}
}
/// The main "type relation" routine. Note that this does not handle
/// inference artifacts, so you should filter those out before calling
/// it.
pub fn super_relate_tys<R: TypeRelation<'tcx>>(
relation: &mut R,
a: Ty<'tcx>,
b: Ty<'tcx>,
) -> RelateResult<'tcx, Ty<'tcx>> {
let tcx = relation.tcx();
debug!("super_relate_tys: a={:?} b={:?}", a, b);
match (&a.sty, &b.sty) {
(&ty::Infer(_), _) |
(_, &ty::Infer(_)) =>
{
// The caller should handle these cases!
bug!("var types encountered in super_relate_tys")
}
(ty::Bound(..), _) | (_, ty::Bound(..)) => {
bug!("bound types encountered in super_relate_tys")
}
(&ty::Error, _) | (_, &ty::Error) =>
{
Ok(tcx.types.err)
}
(&ty::Never, _) |
(&ty::Char, _) |
(&ty::Bool, _) |
(&ty::Int(_), _) |
(&ty::Uint(_), _) |
(&ty::Float(_), _) |
(&ty::Str, _)
if a == b =>
{
Ok(a)
}
(&ty::Param(ref a_p), &ty::Param(ref b_p))
if a_p.index == b_p.index =>
{
Ok(a)
}
(ty::Placeholder(p1), ty::Placeholder(p2)) if p1 == p2 => {
Ok(a)
}
(&ty::Adt(a_def, a_substs), &ty::Adt(b_def, b_substs))
if a_def == b_def =>
{
let substs = relation.relate_item_substs(a_def.did, a_substs, b_substs)?;
Ok(tcx.mk_adt(a_def, substs))
}
(&ty::Foreign(a_id), &ty::Foreign(b_id))
if a_id == b_id =>
{
Ok(tcx.mk_foreign(a_id))
}
(&ty::Dynamic(ref a_obj, ref a_region), &ty::Dynamic(ref b_obj, ref b_region)) => {
let region_bound = relation.with_cause(Cause::ExistentialRegionBound,
|relation| {
relation.relate_with_variance(
ty::Contravariant,
a_region,
b_region)
})?;
Ok(tcx.mk_dynamic(relation.relate(a_obj, b_obj)?, region_bound))
}
(&ty::Generator(a_id, a_substs, movability),
&ty::Generator(b_id, b_substs, _))
if a_id == b_id =>
{
// All Generator types with the same id represent
// the (anonymous) type of the same generator expression. So
// all of their regions should be equated.
let substs = relation.relate(&a_substs, &b_substs)?;
Ok(tcx.mk_generator(a_id, substs, movability))
}
(&ty::GeneratorWitness(a_types), &ty::GeneratorWitness(b_types)) =>
{
// Wrap our types with a temporary GeneratorWitness struct
// inside the binder so we can related them
let a_types = a_types.map_bound(GeneratorWitness);
let b_types = b_types.map_bound(GeneratorWitness);
// Then remove the GeneratorWitness for the result
let types = relation.relate(&a_types, &b_types)?.map_bound(|witness| witness.0);
Ok(tcx.mk_generator_witness(types))
}
(&ty::Closure(a_id, a_substs),
&ty::Closure(b_id, b_substs))
if a_id == b_id =>
{
// All Closure types with the same id represent
// the (anonymous) type of the same closure expression. So
// all of their regions should be equated.
let substs = relation.relate(&a_substs, &b_substs)?;
Ok(tcx.mk_closure(a_id, substs))
}
(&ty::RawPtr(ref a_mt), &ty::RawPtr(ref b_mt)) =>
{
let mt = relation.relate(a_mt, b_mt)?;
Ok(tcx.mk_ptr(mt))
}
(&ty::Ref(a_r, a_ty, a_mutbl), &ty::Ref(b_r, b_ty, b_mutbl)) =>
{
let r = relation.relate_with_variance(ty::Contravariant, &a_r, &b_r)?;
let a_mt = ty::TypeAndMut { ty: a_ty, mutbl: a_mutbl };
let b_mt = ty::TypeAndMut { ty: b_ty, mutbl: b_mutbl };
let mt = relation.relate(&a_mt, &b_mt)?;
Ok(tcx.mk_ref(r, mt))
}
(&ty::Array(a_t, sz_a), &ty::Array(b_t, sz_b)) =>
{
let t = relation.relate(&a_t, &b_t)?;
match relation.relate(&sz_a, &sz_b) {
Ok(sz) => Ok(tcx.mk_ty(ty::Array(t, sz))),
Err(err) => {
// Check whether the lengths are both concrete/known values,
// but are unequal, for better diagnostics.
match (sz_a.assert_usize(tcx), sz_b.assert_usize(tcx)) {
(Some(sz_a_val), Some(sz_b_val)) => {
Err(TypeError::FixedArraySize(
expected_found(relation, &sz_a_val, &sz_b_val)
))
}
_ => return Err(err),
}
}
}
}
(&ty::Slice(a_t), &ty::Slice(b_t)) =>
{
let t = relation.relate(&a_t, &b_t)?;
Ok(tcx.mk_slice(t))
}
(&ty::Tuple(as_), &ty::Tuple(bs)) =>
{
if as_.len() == bs.len() {
Ok(tcx.mk_tup(as_.iter().zip(bs).map(|(a, b)| {
relation.relate(&a.expect_ty(), &b.expect_ty())
}))?)
} else if !(as_.is_empty() || bs.is_empty()) {
Err(TypeError::TupleSize(
expected_found(relation, &as_.len(), &bs.len())))
} else {
Err(TypeError::Sorts(expected_found(relation, &a, &b)))
}
}
(&ty::FnDef(a_def_id, a_substs), &ty::FnDef(b_def_id, b_substs))
if a_def_id == b_def_id =>
{
let substs = relation.relate_item_substs(a_def_id, a_substs, b_substs)?;
Ok(tcx.mk_fn_def(a_def_id, substs))
}
(&ty::FnPtr(a_fty), &ty::FnPtr(b_fty)) =>
{
let fty = relation.relate(&a_fty, &b_fty)?;
Ok(tcx.mk_fn_ptr(fty))
}
(ty::UnnormalizedProjection(a_data), ty::UnnormalizedProjection(b_data)) => {
let projection_ty = relation.relate(a_data, b_data)?;
Ok(tcx.mk_ty(ty::UnnormalizedProjection(projection_ty)))
}
// these two are already handled downstream in case of lazy normalization
(ty::Projection(a_data), ty::Projection(b_data)) => {
let projection_ty = relation.relate(a_data, b_data)?;
Ok(tcx.mk_projection(projection_ty.item_def_id, projection_ty.substs))
}
(&ty::Opaque(a_def_id, a_substs), &ty::Opaque(b_def_id, b_substs))
if a_def_id == b_def_id =>
{
let substs = relate_substs(relation, None, a_substs, b_substs)?;
Ok(tcx.mk_opaque(a_def_id, substs))
}
_ =>
{
Err(TypeError::Sorts(expected_found(relation, &a, &b)))
}
}
}
/// The main "const relation" routine. Note that this does not handle
/// inference artifacts, so you should filter those out before calling
/// it.
pub fn super_relate_consts<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &'tcx ty::Const<'tcx>,
b: &'tcx ty::Const<'tcx>,
) -> RelateResult<'tcx, &'tcx ty::Const<'tcx>> {
let tcx = relation.tcx();
let eagerly_eval = |x: &'tcx ty::Const<'tcx>| {
if let ConstValue::Unevaluated(def_id, substs) = x.val {
// FIXME(eddyb) get the right param_env.
let param_env = ty::ParamEnv::empty();
if !substs.has_local_value() {
let instance = ty::Instance::resolve(
tcx.global_tcx(),
param_env,
def_id,
substs,
);
if let Some(instance) = instance {
let cid = GlobalId {
instance,
promoted: None,
};
if let Ok(ct) = tcx.const_eval(param_env.and(cid)) {
return ct.val;
}
}
}
}
x.val
};
// Currently, the values that can be unified are those that
// implement both `PartialEq` and `Eq`, corresponding to
// `structural_match` types.
// FIXME(const_generics): check for `structural_match` synthetic attribute.
match (eagerly_eval(a), eagerly_eval(b)) {
(ConstValue::Infer(_), _) | (_, ConstValue::Infer(_)) => {
// The caller should handle these cases!
bug!("var types encountered in super_relate_consts: {:?} {:?}", a, b)
}
(ConstValue::Param(a_p), ConstValue::Param(b_p)) if a_p.index == b_p.index => {
Ok(a)
}
(ConstValue::Placeholder(p1), ConstValue::Placeholder(p2)) if p1 == p2 => {
Ok(a)
}
(a_val @ ConstValue::Scalar(Scalar::Raw { .. }), b_val @ _)
if a.ty == b.ty && a_val == b_val =>
{
Ok(tcx.mk_const(ty::Const {
val: a_val,
ty: a.ty,
}))
}
(ConstValue::ByRef { .. }, _) => {
bug!(
"non-Scalar ConstValue encountered in super_relate_consts {:?} {:?}",
a,
b,
);
}
// FIXME(const_generics): this is wrong, as it is a projection
(ConstValue::Unevaluated(a_def_id, a_substs),
ConstValue::Unevaluated(b_def_id, b_substs)) if a_def_id == b_def_id => {
let substs =
relation.relate_with_variance(ty::Variance::Invariant, &a_substs, &b_substs)?;
Ok(tcx.mk_const(ty::Const {
val: ConstValue::Unevaluated(a_def_id, &substs),
ty: a.ty,
}))
}
_ => Err(TypeError::ConstMismatch(expected_found(relation, &a, &b))),
}
}
impl<'tcx> Relate<'tcx> for &'tcx ty::List<ty::ExistentialPredicate<'tcx>> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &Self,
b: &Self,
) -> RelateResult<'tcx, Self> {
if a.len() != b.len() {
return Err(TypeError::ExistentialMismatch(expected_found(relation, a, b)));
}
let tcx = relation.tcx();
let v = a.iter().zip(b.iter()).map(|(ep_a, ep_b)| {
use crate::ty::ExistentialPredicate::*;
match (*ep_a, *ep_b) {
(Trait(ref a), Trait(ref b)) => Ok(Trait(relation.relate(a, b)?)),
(Projection(ref a), Projection(ref b)) => Ok(Projection(relation.relate(a, b)?)),
(AutoTrait(ref a), AutoTrait(ref b)) if a == b => Ok(AutoTrait(*a)),
_ => Err(TypeError::ExistentialMismatch(expected_found(relation, a, b)))
}
});
Ok(tcx.mk_existential_predicates(v)?)
}
}
impl<'tcx> Relate<'tcx> for ty::ClosureSubsts<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::ClosureSubsts<'tcx>,
b: &ty::ClosureSubsts<'tcx>,
) -> RelateResult<'tcx, ty::ClosureSubsts<'tcx>> {
let substs = relate_substs(relation, None, a.substs, b.substs)?;
Ok(ty::ClosureSubsts { substs })
}
}
impl<'tcx> Relate<'tcx> for ty::GeneratorSubsts<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::GeneratorSubsts<'tcx>,
b: &ty::GeneratorSubsts<'tcx>,
) -> RelateResult<'tcx, ty::GeneratorSubsts<'tcx>> {
let substs = relate_substs(relation, None, a.substs, b.substs)?;
Ok(ty::GeneratorSubsts { substs })
}
}
impl<'tcx> Relate<'tcx> for SubstsRef<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &SubstsRef<'tcx>,
b: &SubstsRef<'tcx>,
) -> RelateResult<'tcx, SubstsRef<'tcx>> {
relate_substs(relation, None, a, b)
}
}
impl<'tcx> Relate<'tcx> for ty::Region<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::Region<'tcx>,
b: &ty::Region<'tcx>,
) -> RelateResult<'tcx, ty::Region<'tcx>> {
relation.regions(*a, *b)
}
}
impl<'tcx> Relate<'tcx> for &'tcx ty::Const<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &&'tcx ty::Const<'tcx>,
b: &&'tcx ty::Const<'tcx>,
) -> RelateResult<'tcx, &'tcx ty::Const<'tcx>> {
relation.consts(*a, *b)
}
}
impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for ty::Binder<T> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::Binder<T>,
b: &ty::Binder<T>,
) -> RelateResult<'tcx, ty::Binder<T>> {
relation.binders(a, b)
}
}
impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for Rc<T> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &Rc<T>,
b: &Rc<T>,
) -> RelateResult<'tcx, Rc<T>> {
let a: &T = a;
let b: &T = b;
Ok(Rc::new(relation.relate(a, b)?))
}
}
impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for Box<T> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &Box<T>,
b: &Box<T>,
) -> RelateResult<'tcx, Box<T>> {
let a: &T = a;
let b: &T = b;
Ok(Box::new(relation.relate(a, b)?))
}
}
impl<'tcx> Relate<'tcx> for Kind<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &Kind<'tcx>,
b: &Kind<'tcx>,
) -> RelateResult<'tcx, Kind<'tcx>> {
match (a.unpack(), b.unpack()) {
(UnpackedKind::Lifetime(a_lt), UnpackedKind::Lifetime(b_lt)) => {
Ok(relation.relate(&a_lt, &b_lt)?.into())
}
(UnpackedKind::Type(a_ty), UnpackedKind::Type(b_ty)) => {
Ok(relation.relate(&a_ty, &b_ty)?.into())
}
(UnpackedKind::Const(a_ct), UnpackedKind::Const(b_ct)) => {
Ok(relation.relate(&a_ct, &b_ct)?.into())
}
(UnpackedKind::Lifetime(unpacked), x) => {
bug!("impossible case reached: can't relate: {:?} with {:?}", unpacked, x)
}
(UnpackedKind::Type(unpacked), x) => {
bug!("impossible case reached: can't relate: {:?} with {:?}", unpacked, x)
}
(UnpackedKind::Const(unpacked), x) => {
bug!("impossible case reached: can't relate: {:?} with {:?}", unpacked, x)
}
}
}
}
impl<'tcx> Relate<'tcx> for ty::TraitPredicate<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::TraitPredicate<'tcx>,
b: &ty::TraitPredicate<'tcx>,
) -> RelateResult<'tcx, ty::TraitPredicate<'tcx>> {
Ok(ty::TraitPredicate {
trait_ref: relation.relate(&a.trait_ref, &b.trait_ref)?,
})
}
}
impl<'tcx> Relate<'tcx> for ty::ProjectionPredicate<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &ty::ProjectionPredicate<'tcx>,
b: &ty::ProjectionPredicate<'tcx>,
) -> RelateResult<'tcx, ty::ProjectionPredicate<'tcx>> {
Ok(ty::ProjectionPredicate {
projection_ty: relation.relate(&a.projection_ty, &b.projection_ty)?,
ty: relation.relate(&a.ty, &b.ty)?,
})
}
}
impl<'tcx> Relate<'tcx> for traits::WhereClause<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::WhereClause<'tcx>,
b: &traits::WhereClause<'tcx>,
) -> RelateResult<'tcx, traits::WhereClause<'tcx>> {
use crate::traits::WhereClause::*;
match (a, b) {
(Implemented(a_pred), Implemented(b_pred)) => {
Ok(Implemented(relation.relate(a_pred, b_pred)?))
}
(ProjectionEq(a_pred), ProjectionEq(b_pred)) => {
Ok(ProjectionEq(relation.relate(a_pred, b_pred)?))
}
(RegionOutlives(a_pred), RegionOutlives(b_pred)) => {
Ok(RegionOutlives(ty::OutlivesPredicate(
relation.relate(&a_pred.0, &b_pred.0)?,
relation.relate(&a_pred.1, &b_pred.1)?,
)))
}
(TypeOutlives(a_pred), TypeOutlives(b_pred)) => {
Ok(TypeOutlives(ty::OutlivesPredicate(
relation.relate(&a_pred.0, &b_pred.0)?,
relation.relate(&a_pred.1, &b_pred.1)?,
)))
}
_ => Err(TypeError::Mismatch),
}
}
}
impl<'tcx> Relate<'tcx> for traits::WellFormed<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::WellFormed<'tcx>,
b: &traits::WellFormed<'tcx>,
) -> RelateResult<'tcx, traits::WellFormed<'tcx>> {
use crate::traits::WellFormed::*;
match (a, b) {
(Trait(a_pred), Trait(b_pred)) => Ok(Trait(relation.relate(a_pred, b_pred)?)),
(Ty(a_ty), Ty(b_ty)) => Ok(Ty(relation.relate(a_ty, b_ty)?)),
_ => Err(TypeError::Mismatch),
}
}
}
impl<'tcx> Relate<'tcx> for traits::FromEnv<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::FromEnv<'tcx>,
b: &traits::FromEnv<'tcx>,
) -> RelateResult<'tcx, traits::FromEnv<'tcx>> {
use crate::traits::FromEnv::*;
match (a, b) {
(Trait(a_pred), Trait(b_pred)) => Ok(Trait(relation.relate(a_pred, b_pred)?)),
(Ty(a_ty), Ty(b_ty)) => Ok(Ty(relation.relate(a_ty, b_ty)?)),
_ => Err(TypeError::Mismatch),
}
}
}
impl<'tcx> Relate<'tcx> for traits::DomainGoal<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::DomainGoal<'tcx>,
b: &traits::DomainGoal<'tcx>,
) -> RelateResult<'tcx, traits::DomainGoal<'tcx>> {
use crate::traits::DomainGoal::*;
match (a, b) {
(Holds(a_wc), Holds(b_wc)) => Ok(Holds(relation.relate(a_wc, b_wc)?)),
(WellFormed(a_wf), WellFormed(b_wf)) => Ok(WellFormed(relation.relate(a_wf, b_wf)?)),
(FromEnv(a_fe), FromEnv(b_fe)) => Ok(FromEnv(relation.relate(a_fe, b_fe)?)),
(Normalize(a_pred), Normalize(b_pred)) => {
Ok(Normalize(relation.relate(a_pred, b_pred)?))
}
_ => Err(TypeError::Mismatch),
}
}
}
impl<'tcx> Relate<'tcx> for traits::Goal<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::Goal<'tcx>,
b: &traits::Goal<'tcx>,
) -> RelateResult<'tcx, traits::Goal<'tcx>> {
use crate::traits::GoalKind::*;
match (a, b) {
(Implies(a_clauses, a_goal), Implies(b_clauses, b_goal)) => {
let clauses = relation.relate(a_clauses, b_clauses)?;
let goal = relation.relate(a_goal, b_goal)?;
Ok(relation.tcx().mk_goal(Implies(clauses, goal)))
}
(And(a_left, a_right), And(b_left, b_right)) => {
let left = relation.relate(a_left, b_left)?;
let right = relation.relate(a_right, b_right)?;
Ok(relation.tcx().mk_goal(And(left, right)))
}
(Not(a_goal), Not(b_goal)) => {
let goal = relation.relate(a_goal, b_goal)?;
Ok(relation.tcx().mk_goal(Not(goal)))
}
(DomainGoal(a_goal), DomainGoal(b_goal)) => {
let goal = relation.relate(a_goal, b_goal)?;
Ok(relation.tcx().mk_goal(DomainGoal(goal)))
}
(Quantified(a_qkind, a_goal), Quantified(b_qkind, b_goal))
if a_qkind == b_qkind =>
{
let goal = relation.relate(a_goal, b_goal)?;
Ok(relation.tcx().mk_goal(Quantified(*a_qkind, goal)))
}
(CannotProve, CannotProve) => Ok(*a),
_ => Err(TypeError::Mismatch),
}
}
}
impl<'tcx> Relate<'tcx> for traits::Goals<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::Goals<'tcx>,
b: &traits::Goals<'tcx>,
) -> RelateResult<'tcx, traits::Goals<'tcx>> {
if a.len() != b.len() {
return Err(TypeError::Mismatch);
}
let tcx = relation.tcx();
let goals = a.iter().zip(b.iter()).map(|(a, b)| relation.relate(a, b));
Ok(tcx.mk_goals(goals)?)
}
}
impl<'tcx> Relate<'tcx> for traits::Clause<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::Clause<'tcx>,
b: &traits::Clause<'tcx>,
) -> RelateResult<'tcx, traits::Clause<'tcx>> {
use crate::traits::Clause::*;
match (a, b) {
(Implies(a_clause), Implies(b_clause)) => {
let clause = relation.relate(a_clause, b_clause)?;
Ok(Implies(clause))
}
(ForAll(a_clause), ForAll(b_clause)) => {
let clause = relation.relate(a_clause, b_clause)?;
Ok(ForAll(clause))
}
_ => Err(TypeError::Mismatch),
}
}
}
impl<'tcx> Relate<'tcx> for traits::Clauses<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::Clauses<'tcx>,
b: &traits::Clauses<'tcx>,
) -> RelateResult<'tcx, traits::Clauses<'tcx>> {
if a.len() != b.len() {
return Err(TypeError::Mismatch);
}
let tcx = relation.tcx();
let clauses = a.iter().zip(b.iter()).map(|(a, b)| relation.relate(a, b));
Ok(tcx.mk_clauses(clauses)?)
}
}
impl<'tcx> Relate<'tcx> for traits::ProgramClause<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::ProgramClause<'tcx>,
b: &traits::ProgramClause<'tcx>,
) -> RelateResult<'tcx, traits::ProgramClause<'tcx>> {
Ok(traits::ProgramClause {
goal: relation.relate(&a.goal, &b.goal)?,
hypotheses: relation.relate(&a.hypotheses, &b.hypotheses)?,
category: traits::ProgramClauseCategory::Other,
})
}
}
impl<'tcx> Relate<'tcx> for traits::Environment<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::Environment<'tcx>,
b: &traits::Environment<'tcx>,
) -> RelateResult<'tcx, traits::Environment<'tcx>> {
Ok(traits::Environment {
clauses: relation.relate(&a.clauses, &b.clauses)?,
})
}
}
impl<'tcx, G> Relate<'tcx> for traits::InEnvironment<'tcx, G>
where
G: Relate<'tcx>,
{
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: &traits::InEnvironment<'tcx, G>,
b: &traits::InEnvironment<'tcx, G>,
) -> RelateResult<'tcx, traits::InEnvironment<'tcx, G>> {
Ok(traits::InEnvironment {
environment: relation.relate(&a.environment, &b.environment)?,
goal: relation.relate(&a.goal, &b.goal)?,
})
}
}
///////////////////////////////////////////////////////////////////////////
// Error handling
pub fn expected_found<R, T>(relation: &mut R, a: &T, b: &T) -> ExpectedFound<T>
where
R: TypeRelation<'tcx>,
T: Clone,
{
expected_found_bool(relation.a_is_expected(), a, b)
}
pub fn expected_found_bool<T>(a_is_expected: bool,
a: &T,
b: &T)
-> ExpectedFound<T>
where T: Clone
{
let a = a.clone();
let b = b.clone();
if a_is_expected {
ExpectedFound {expected: a, found: b}
} else {
ExpectedFound {expected: b, found: a}
}
}
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