use crate::mir::interpret::{get_slice_bytes, ConstValue, GlobalAlloc, Scalar};
use crate::ty::error::{ExpectedFound, TypeError};
use crate::ty::subst::{GenericArg, GenericArgKind, SubstsRef};
use crate::ty::{self, Ty, TyCtxt, TypeFoldable};
use rustc_hir as ast;
use rustc_hir::def_id::DefId;
use rustc_span::DUMMY_SP;
use rustc_target::spec::abi;
use std::iter;
pub type RelateResult<'tcx, T> = Result<T, TypeError<'tcx>>;
#[derive(Clone, Debug)]
pub enum Cause {
ExistentialRegionBound,
}
pub trait TypeRelation<'tcx>: Sized {
fn tcx(&self) -> TyCtxt<'tcx>;
fn param_env(&self) -> ty::ParamEnv<'tcx>;
fn tag(&self) -> &'static str;
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)
}
fn relate<T: Relate<'tcx>>(&mut self, a: T, b: T) -> RelateResult<'tcx, T> {
Relate::relate(self, a, b)
}
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)
}
fn relate_with_variance<T: Relate<'tcx>>(
&mut self,
variance: ty::Variance,
a: T,
b: T,
) -> RelateResult<'tcx, T>;
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<'tcx, T>,
b: ty::Binder<'tcx, T>,
) -> RelateResult<'tcx, ty::Binder<'tcx, T>>
where
T: Relate<'tcx>;
}
pub trait Relate<'tcx>: TypeFoldable<'tcx> + Copy {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: Self,
b: Self,
) -> RelateResult<'tcx, Self>;
}
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::Not => ty::Covariant,
ast::Mutability::Mut => 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 = iter::zip(a_subst, b_subst).enumerate().map(|(i, (a, b))| {
let variance = variances.map_or(ty::Invariant, |v| v[i]);
relation.relate_with_variance(variance, a, b)
});
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 = iter::zip(a.inputs(), b.inputs())
.map(|(&a, &b)| ((a, b), 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)
}
})
.enumerate()
.map(|(i, r)| match r {
Err(TypeError::Sorts(exp_found)) => Err(TypeError::ArgumentSorts(exp_found, i)),
Err(TypeError::Mutability) => Err(TypeError::ArgumentMutability(i)),
r => r,
});
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_with_variance(ty::Invariant, a.ty, b.ty)?;
let substs = relation.relate_with_variance(ty::Invariant, a.substs, b.substs)?;
Ok(ty::ExistentialProjection { item_def_id: a.item_def_id, substs, ty })
}
}
}
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>> {
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 })
}
}
}
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>> {
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 })
}
}
}
#[derive(Copy, Debug, Clone, TypeFoldable)]
struct GeneratorWitness<'tcx>(&'tcx ty::List<Ty<'tcx>>);
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(iter::zip(a.0, b.0).map(|(a, b)| relation.relate(a, b)))?;
Ok(GeneratorWitness(types))
}
}
impl<'tcx> Relate<'tcx> for Ty<'tcx> {
#[inline]
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: Ty<'tcx>,
b: Ty<'tcx>,
) -> RelateResult<'tcx, Ty<'tcx>> {
relation.tys(a, b)
}
}
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.kind(), b.kind()) {
(&ty::Infer(_), _) | (_, &ty::Infer(_)) => {
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.ty_error()),
(&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(a_obj, a_region), &ty::Dynamic(b_obj, 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 =>
{
let substs = relation.relate(a_substs, b_substs)?;
Ok(tcx.mk_generator(a_id, substs, movability))
}
(&ty::GeneratorWitness(a_types), &ty::GeneratorWitness(b_types)) => {
let a_types = a_types.map_bound(GeneratorWitness);
let b_types = b_types.map_bound(GeneratorWitness);
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 => {
let substs = relation.relate(a_substs, b_substs)?;
Ok(tcx.mk_closure(a_id, &substs))
}
(&ty::RawPtr(a_mt), &ty::RawPtr(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) => {
let sz_a = sz_a.try_eval_usize(tcx, relation.param_env());
let sz_b = sz_b.try_eval_usize(tcx, relation.param_env());
match (sz_a, sz_b) {
(Some(sz_a_val), Some(sz_b_val)) if sz_a_val != sz_b_val => Err(
TypeError::FixedArraySize(expected_found(relation, sz_a_val, sz_b_val)),
),
_ => 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(
iter::zip(as_, 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::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))),
}
}
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>> {
debug!("{}.super_relate_consts(a = {:?}, b = {:?})", relation.tag(), a, b);
let tcx = relation.tcx();
let a_ty = tcx.erase_regions(a.ty);
let b_ty = tcx.erase_regions(b.ty);
if a_ty != b_ty {
relation.tcx().sess.delay_span_bug(
DUMMY_SP,
&format!("cannot relate constants of different types: {} != {}", a_ty, b_ty),
);
}
let eagerly_eval = |x: &'tcx ty::Const<'tcx>| x.eval(tcx, relation.param_env());
let a = eagerly_eval(a);
let b = eagerly_eval(b);
let is_match = match (a.val, b.val) {
(ty::ConstKind::Infer(_), _) | (_, ty::ConstKind::Infer(_)) => {
bug!("var types encountered in super_relate_consts: {:?} {:?}", a, b)
}
(ty::ConstKind::Error(_), _) => return Ok(a),
(_, ty::ConstKind::Error(_)) => return Ok(b),
(ty::ConstKind::Param(a_p), ty::ConstKind::Param(b_p)) => a_p.index == b_p.index,
(ty::ConstKind::Placeholder(p1), ty::ConstKind::Placeholder(p2)) => p1 == p2,
(ty::ConstKind::Value(a_val), ty::ConstKind::Value(b_val)) => {
check_const_value_eq(relation, a_val, b_val, a, b)?
}
(ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu))
if tcx.features().const_evaluatable_checked =>
{
tcx.try_unify_abstract_consts(((au.def, au.substs), (bu.def, bu.substs)))
}
(ty::ConstKind::Unevaluated(au), ty::ConstKind::Unevaluated(bu))
if au.def == bu.def && au.promoted == bu.promoted =>
{
let substs =
relation.relate_with_variance(ty::Variance::Invariant, au.substs, bu.substs)?;
return Ok(tcx.mk_const(ty::Const {
val: ty::ConstKind::Unevaluated(ty::Unevaluated {
def: au.def,
substs,
promoted: au.promoted,
}),
ty: a.ty,
}));
}
_ => false,
};
if is_match { Ok(a) } else { Err(TypeError::ConstMismatch(expected_found(relation, a, b))) }
}
fn check_const_value_eq<R: TypeRelation<'tcx>>(
relation: &mut R,
a_val: ConstValue<'tcx>,
b_val: ConstValue<'tcx>,
a: &'tcx ty::Const<'tcx>,
b: &'tcx ty::Const<'tcx>,
) -> RelateResult<'tcx, bool> {
let tcx = relation.tcx();
Ok(match (a_val, b_val) {
(ConstValue::Scalar(Scalar::Int(a_val)), ConstValue::Scalar(Scalar::Int(b_val))) => {
a_val == b_val
}
(ConstValue::Scalar(Scalar::Ptr(a_val)), ConstValue::Scalar(Scalar::Ptr(b_val))) => {
a_val == b_val
|| match (tcx.global_alloc(a_val.alloc_id), tcx.global_alloc(b_val.alloc_id)) {
(GlobalAlloc::Function(a_instance), GlobalAlloc::Function(b_instance)) => {
a_instance == b_instance
}
_ => false,
}
}
(ConstValue::Slice { .. }, ConstValue::Slice { .. }) => {
get_slice_bytes(&tcx, a_val) == get_slice_bytes(&tcx, b_val)
}
(ConstValue::ByRef { .. }, ConstValue::ByRef { .. }) => {
let a_destructured = tcx.destructure_const(relation.param_env().and(a));
let b_destructured = tcx.destructure_const(relation.param_env().and(b));
if a_destructured.variant == b_destructured.variant {
for (a_field, b_field) in iter::zip(a_destructured.fields, b_destructured.fields) {
relation.consts(a_field, b_field)?;
}
true
} else {
false
}
}
_ => false,
})
}
impl<'tcx> Relate<'tcx> for &'tcx ty::List<ty::Binder<'tcx, ty::ExistentialPredicate<'tcx>>> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: Self,
b: Self,
) -> RelateResult<'tcx, Self> {
let tcx = relation.tcx();
let mut a_v: Vec<_> = a.into_iter().collect();
let mut b_v: Vec<_> = b.into_iter().collect();
a_v.sort_by(|a, b| a.skip_binder().stable_cmp(tcx, &b.skip_binder()));
a_v.dedup();
b_v.sort_by(|a, b| a.skip_binder().stable_cmp(tcx, &b.skip_binder()));
b_v.dedup();
if a_v.len() != b_v.len() {
return Err(TypeError::ExistentialMismatch(expected_found(relation, a, b)));
}
let v = iter::zip(a_v, b_v).map(|(ep_a, ep_b)| {
use crate::ty::ExistentialPredicate::*;
match (ep_a.skip_binder(), ep_b.skip_binder()) {
(Trait(a), Trait(b)) => Ok(ep_a
.rebind(Trait(relation.relate(ep_a.rebind(a), ep_b.rebind(b))?.skip_binder()))),
(Projection(a), Projection(b)) => Ok(ep_a.rebind(Projection(
relation.relate(ep_a.rebind(a), ep_b.rebind(b))?.skip_binder(),
))),
(AutoTrait(a), AutoTrait(b)) if a == b => Ok(ep_a.rebind(AutoTrait(a))),
_ => Err(TypeError::ExistentialMismatch(expected_found(relation, a, b))),
}
});
tcx.mk_poly_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<'tcx, T> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: ty::Binder<'tcx, T>,
b: ty::Binder<'tcx, T>,
) -> RelateResult<'tcx, ty::Binder<'tcx, T>> {
relation.binders(a, b)
}
}
impl<'tcx> Relate<'tcx> for GenericArg<'tcx> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: GenericArg<'tcx>,
b: GenericArg<'tcx>,
) -> RelateResult<'tcx, GenericArg<'tcx>> {
match (a.unpack(), b.unpack()) {
(GenericArgKind::Lifetime(a_lt), GenericArgKind::Lifetime(b_lt)) => {
Ok(relation.relate(a_lt, b_lt)?.into())
}
(GenericArgKind::Type(a_ty), GenericArgKind::Type(b_ty)) => {
Ok(relation.relate(a_ty, b_ty)?.into())
}
(GenericArgKind::Const(a_ct), GenericArgKind::Const(b_ct)) => {
Ok(relation.relate(a_ct, b_ct)?.into())
}
(GenericArgKind::Lifetime(unpacked), x) => {
bug!("impossible case reached: can't relate: {:?} with {:?}", unpacked, x)
}
(GenericArgKind::Type(unpacked), x) => {
bug!("impossible case reached: can't relate: {:?} with {:?}", unpacked, x)
}
(GenericArgKind::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)?,
})
}
}
pub fn expected_found<R, T>(relation: &mut R, a: T, b: T) -> ExpectedFound<T>
where
R: TypeRelation<'tcx>,
{
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> {
if a_is_expected {
ExpectedFound { expected: a, found: b }
} else {
ExpectedFound { expected: b, found: a }
}
}