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Unify Opaque/Projection handling in region outlives code

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This commit is contained in:
Michael Goulet 2023-01-13 23:53:28 +00:00
parent 0b90256ada
commit 1ea6862db3
12 changed files with 54 additions and 114 deletions
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9
compiler/rustc_infer/src/infer/error_reporting/mod.rs
View file

@ -2256,9 +2256,12 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
let labeled_user_string = match bound_kind {
GenericKind::Param(ref p) => format!("the parameter type `{}`", p),
GenericKind::Projection(ref p) => format!("the associated type `{}`", p),
GenericKind::Opaque(def_id, substs) => {
format!("the opaque type `{}`", self.tcx.def_path_str_with_substs(def_id, substs))
GenericKind::Alias(ty::Projection, ref p) => format!("the associated type `{}`", p),
GenericKind::Alias(ty::Opaque, ref p) => {
format!(
"the opaque type `{}`",
self.tcx.def_path_str_with_substs(p.def_id, p.substs)
)
}
};

15
compiler/rustc_infer/src/infer/outlives/components.rs
View file

@ -3,9 +3,8 @@
// RFC for reference.
use rustc_data_structures::sso::SsoHashSet;
use rustc_hir::def_id::DefId;
use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
use rustc_middle::ty::{self, SubstsRef, Ty, TyCtxt, TypeVisitable};
use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable};
use smallvec::{smallvec, SmallVec};
#[derive(Debug)]
@ -23,7 +22,7 @@ pub enum Component<'tcx> {
// is not in a position to judge which is the best technique, so
// we just product the projection as a component and leave it to
// the consumer to decide (but see `EscapingProjection` below).
Projection(ty::AliasTy<'tcx>),
Alias(ty::AliasKind, ty::AliasTy<'tcx>),
// In the case where a projection has escaping regions -- meaning
// regions bound within the type itself -- we always use
@ -46,8 +45,6 @@ pub enum Component<'tcx> {
// them. This gives us room to improve the regionck reasoning in
// the future without breaking backwards compat.
EscapingProjection(Vec<Component<'tcx>>),
Opaque(DefId, SubstsRef<'tcx>),
}
/// Push onto `out` all the things that must outlive `'a` for the condition
@ -130,8 +127,8 @@ fn compute_components<'tcx>(
// outlives any other lifetime, which is unsound.
// See https://github.com/rust-lang/rust/issues/84305 for
// more details.
ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
out.push(Component::Opaque(def_id, substs));
ty::Alias(ty::Opaque, data) => {
out.push(Component::Alias(ty::Opaque, data));
},
// For projections, we prefer to generate an obligation like
@ -142,7 +139,7 @@ fn compute_components<'tcx>(
// trait-ref. Therefore, if we see any higher-ranked regions,
// we simply fallback to the most restrictive rule, which
// requires that `Pi: 'a` for all `i`.
ty::Alias(ty::Projection, ref data) => {
ty::Alias(ty::Projection, data) => {
if !data.has_escaping_bound_vars() {
// best case: no escaping regions, so push the
// projection and skip the subtree (thus generating no
@ -150,7 +147,7 @@ fn compute_components<'tcx>(
// the rules OutlivesProjectionEnv,
// OutlivesProjectionTraitDef, and
// OutlivesProjectionComponents to regionck.
out.push(Component::Projection(*data));
out.push(Component::Alias(ty::Projection, data));
} else {
// fallback case: hard code
// OutlivesProjectionComponents. Continue walking

8
compiler/rustc_infer/src/infer/outlives/env.rs
View file

@ -138,13 +138,9 @@ impl<'tcx> OutlivesEnvironmentBuilder<'tcx> {
self.region_bound_pairs
.insert(ty::OutlivesPredicate(GenericKind::Param(param_b), r_a));
}
OutlivesBound::RegionSubProjection(r_a, projection_b) => {
OutlivesBound::RegionSubAlias(r_a, kind, projection_b) => {
self.region_bound_pairs
.insert(ty::OutlivesPredicate(GenericKind::Projection(projection_b), r_a));
}
OutlivesBound::RegionSubOpaque(r_a, def_id, substs) => {
self.region_bound_pairs
.insert(ty::OutlivesPredicate(GenericKind::Opaque(def_id, substs), r_a));
.insert(ty::OutlivesPredicate(GenericKind::Alias(kind, projection_b), r_a));
}
OutlivesBound::RegionSubRegion(r_a, r_b) => {
if let (ReEarlyBound(_) | ReFree(_), ReVar(vid_b)) = (r_a.kind(), r_b.kind()) {

48
compiler/rustc_infer/src/infer/outlives/obligations.rs
View file

@ -266,11 +266,8 @@ where
Component::Param(param_ty) => {
self.param_ty_must_outlive(origin, region, *param_ty);
}
Component::Opaque(def_id, substs) => {
self.opaque_must_outlive(*def_id, substs, origin, region)
}
Component::Projection(projection_ty) => {
self.projection_must_outlive(origin, region, *projection_ty);
Component::Alias(kind, data) => {
self.alias_must_outlive(*kind, *data, origin, region)
}
Component::EscapingProjection(subcomponents) => {
self.components_must_outlive(origin, &subcomponents, region, category);
@ -305,44 +302,25 @@ where
}
#[instrument(level = "debug", skip(self))]
fn opaque_must_outlive(
fn alias_must_outlive(
&mut self,
def_id: DefId,
substs: SubstsRef<'tcx>,
kind: ty::AliasKind,
data: ty::AliasTy<'tcx>,
origin: infer::SubregionOrigin<'tcx>,
region: ty::Region<'tcx>,
) {
self.generic_must_outlive(
origin,
region,
GenericKind::Opaque(def_id, substs),
def_id,
substs,
true,
GenericKind::Alias(kind, data),
data.def_id,
data.substs,
kind == ty::Opaque,
|ty| match *ty.kind() {
ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => (def_id, substs),
_ => bug!("expected only projection types from env, not {:?}", ty),
},
);
}
#[instrument(level = "debug", skip(self))]
fn projection_must_outlive(
&mut self,
origin: infer::SubregionOrigin<'tcx>,
region: ty::Region<'tcx>,
projection_ty: ty::AliasTy<'tcx>,
) {
self.generic_must_outlive(
origin,
region,
GenericKind::Projection(projection_ty),
projection_ty.def_id,
projection_ty.substs,
false,
|ty| match ty.kind() {
ty::Alias(ty::Projection, projection_ty) => {
(projection_ty.def_id, projection_ty.substs)
ty::Alias(filter_kind, ty::AliasTy { def_id, substs, .. })
if kind == filter_kind =>
{
(def_id, substs)
}
_ => bug!("expected only projection types from env, not {:?}", ty),
},

14
compiler/rustc_infer/src/infer/outlives/verify.rs
View file

@ -170,16 +170,10 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
match *component {
Component::Region(lt) => VerifyBound::OutlivedBy(lt),
Component::Param(param_ty) => self.param_bound(param_ty),
Component::Opaque(did, substs) => self.projection_opaque_bounds(
GenericKind::Opaque(did, substs),
did,
substs,
visited,
),
Component::Projection(projection_ty) => self.projection_opaque_bounds(
GenericKind::Projection(projection_ty),
projection_ty.def_id,
projection_ty.substs,
Component::Alias(kind, data) => self.projection_opaque_bounds(
GenericKind::Alias(kind, data),
data.def_id,
data.substs,
visited,
),
Component::EscapingProjection(ref components) => {

20
compiler/rustc_infer/src/infer/region_constraints/mod.rs
View file

@ -12,10 +12,8 @@ use rustc_data_structures::intern::Interned;
use rustc_data_structures::sync::Lrc;
use rustc_data_structures::undo_log::UndoLogs;
use rustc_data_structures::unify as ut;
use rustc_hir::def_id::DefId;
use rustc_index::vec::IndexVec;
use rustc_middle::infer::unify_key::{RegionVidKey, UnifiedRegion};
use rustc_middle::ty::subst::SubstsRef;
use rustc_middle::ty::ReStatic;
use rustc_middle::ty::{self, Ty, TyCtxt};
use rustc_middle::ty::{ReLateBound, ReVar};
@ -169,8 +167,7 @@ pub struct Verify<'tcx> {
#[derive(Copy, Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable)]
pub enum GenericKind<'tcx> {
Param(ty::ParamTy),
Projection(ty::AliasTy<'tcx>),
Opaque(DefId, SubstsRef<'tcx>),
Alias(ty::AliasKind, ty::AliasTy<'tcx>),
}
/// Describes the things that some `GenericKind` value `G` is known to
@ -749,9 +746,9 @@ impl<'tcx> fmt::Debug for GenericKind<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
GenericKind::Param(ref p) => write!(f, "{:?}", p),
GenericKind::Projection(ref p) => write!(f, "{:?}", p),
GenericKind::Opaque(def_id, substs) => ty::tls::with(|tcx| {
write!(f, "{}", tcx.def_path_str_with_substs(def_id, tcx.lift(substs).unwrap()))
GenericKind::Alias(ty::Projection, ref p) => write!(f, "{:?}", p),
GenericKind::Alias(ty::Opaque, ref p) => ty::tls::with(|tcx| {
write!(f, "{}", tcx.def_path_str_with_substs(p.def_id, tcx.lift(p.substs).unwrap()))
}),
}
}
@ -761,9 +758,9 @@ impl<'tcx> fmt::Display for GenericKind<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
GenericKind::Param(ref p) => write!(f, "{}", p),
GenericKind::Projection(ref p) => write!(f, "{}", p),
GenericKind::Opaque(def_id, substs) => ty::tls::with(|tcx| {
write!(f, "{}", tcx.def_path_str_with_substs(def_id, tcx.lift(substs).unwrap()))
GenericKind::Alias(ty::Projection, ref p) => write!(f, "{}", p),
GenericKind::Alias(ty::Opaque, ref p) => ty::tls::with(|tcx| {
write!(f, "{}", tcx.def_path_str_with_substs(p.def_id, tcx.lift(p.substs).unwrap()))
}),
}
}
@ -773,8 +770,7 @@ impl<'tcx> GenericKind<'tcx> {
pub fn to_ty(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
match *self {
GenericKind::Param(ref p) => p.to_ty(tcx),
GenericKind::Projection(ref p) => tcx.mk_projection(p.def_id, p.substs),
GenericKind::Opaque(def_id, substs) => tcx.mk_opaque(def_id, substs),
GenericKind::Alias(kind, data) => tcx.mk_ty(ty::Alias(kind, data)),
}
}
}

13
compiler/rustc_infer/src/traits/util.rs
View file

@ -249,17 +249,8 @@ impl<'tcx> Elaborator<'tcx> {
Component::UnresolvedInferenceVariable(_) => None,
Component::Opaque(def_id, substs) => {
let ty = tcx.mk_opaque(def_id, substs);
Some(ty::PredicateKind::Clause(ty::Clause::TypeOutlives(
ty::OutlivesPredicate(ty, r_min),
)))
}
Component::Projection(projection) => {
// We might end up here if we have `Foo<<Bar as Baz>::Assoc>: 'a`.
// With this, we can deduce that `<Bar as Baz>::Assoc: 'a`.
let ty = tcx.mk_projection(projection.def_id, projection.substs);
Component::Alias(kind, data) => {
let ty = tcx.mk_ty(ty::Alias(kind, data));
Some(ty::PredicateKind::Clause(ty::Clause::TypeOutlives(
ty::OutlivesPredicate(ty, r_min),
)))