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Replace tuple of infer vars for upvar_tys with single infer var

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This commit allows us to decide the number of captures required after
completing capture ananysis, which is required as part of implementing
RFC-2229.

Co-authored-by: Aman Arora <me@aman-arora.com>
Co-authored-by: Jenny Wills <wills.jenniferg@gmail.com>
This commit is contained in:
Roxane 2020-07-19 17:26:51 -04:00 • committed by Aman Arora
parent 25d2d09da7
commit dc183702da
23 changed files with 178 additions and 95 deletions
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40
compiler/rustc_trait_selection/src/opaque_types.rs
View file

@ -441,6 +441,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
for required_region in required_region_bounds {
concrete_ty.visit_with(&mut ConstrainOpaqueTypeRegionVisitor {
infcx: self,
op: |r| self.sub_regions(infer::CallReturn(span), required_region, r),
});
}
@ -509,6 +510,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
}
}
concrete_ty.visit_with(&mut ConstrainOpaqueTypeRegionVisitor {
infcx: self,
op: |r| self.sub_regions(infer::CallReturn(span), least_region, r),
});
}
@ -543,6 +545,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
);
concrete_ty.visit_with(&mut ConstrainOpaqueTypeRegionVisitor {
infcx: self,
op: |r| {
self.member_constraint(
opaque_type_def_id,
@ -683,11 +686,12 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
//
// We ignore any type parameters because impl trait values are assumed to
// capture all the in-scope type parameters.
struct ConstrainOpaqueTypeRegionVisitor<OP> {
struct ConstrainOpaqueTypeRegionVisitor<'cx, 'tcx, OP> {
infcx: &'cx InferCtxt<'cx, 'tcx>,
op: OP,
}
impl<'tcx, OP> TypeVisitor<'tcx> for ConstrainOpaqueTypeRegionVisitor<OP>
impl<'cx, 'tcx, OP> TypeVisitor<'tcx> for ConstrainOpaqueTypeRegionVisitor<'cx, 'tcx, OP>
where
OP: FnMut(ty::Region<'tcx>),
{
@ -717,24 +721,36 @@ where
ty::Closure(_, ref substs) => {
// Skip lifetime parameters of the enclosing item(s)
for upvar_ty in substs.as_closure().upvar_tys() {
upvar_ty.visit_with(self);
}
let ty = self.infcx.shallow_resolve(substs.as_closure().tupled_upvars_ty());
if let ty::Infer(ty::TyVar(_)) = ty.kind() {
// Not yet resolved.
ty.super_visit_with(self);
} else {
for upvar_ty in substs.as_closure().upvar_tys() {
upvar_ty.visit_with(self);
}
substs.as_closure().sig_as_fn_ptr_ty().visit_with(self);
substs.as_closure().sig_as_fn_ptr_ty().visit_with(self);
}
}
ty::Generator(_, ref substs, _) => {
// Skip lifetime parameters of the enclosing item(s)
// Also skip the witness type, because that has no free regions.
for upvar_ty in substs.as_generator().upvar_tys() {
upvar_ty.visit_with(self);
}
let ty = self.infcx.shallow_resolve(substs.as_generator().tupled_upvars_ty());
if let ty::Infer(ty::TyVar(_)) = ty.kind() {
// Not yet resolved.
ty.super_visit_with(self);
} else {
for upvar_ty in substs.as_generator().upvar_tys() {
upvar_ty.visit_with(self);
}
substs.as_generator().return_ty().visit_with(self);
substs.as_generator().yield_ty().visit_with(self);
substs.as_generator().resume_ty().visit_with(self);
substs.as_generator().return_ty().visit_with(self);
substs.as_generator().yield_ty().visit_with(self);
substs.as_generator().resume_ty().visit_with(self);
}
}
_ => {
ty.super_visit_with(self);

10
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View file

@ -1307,6 +1307,9 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
let mut generator = None;
let mut outer_generator = None;
let mut next_code = Some(&obligation.cause.code);
let mut seen_upvar_tys_infer_tuple = false;
while let Some(code) = next_code {
debug!("maybe_note_obligation_cause_for_async_await: code={:?}", code);
match code {
@ -1327,6 +1330,13 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
outer_generator = Some(did);
}
ty::GeneratorWitness(..) => {}
ty::Tuple(_) if !seen_upvar_tys_infer_tuple => {
// By introducing a tuple of upvar types into the chain of obligations
// of a generator, the first non-generator item is now the tuple itself,
// we shall ignore this.
seen_upvar_tys_infer_tuple = true;
}
_ if generator.is_none() => {
trait_ref = Some(derived_obligation.parent_trait_ref.skip_binder());
target_ty = Some(ty);

2
compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs
View file

@ -110,7 +110,7 @@ pub fn trivial_dropck_outlives<'tcx>(tcx: TyCtxt<'tcx>, ty: Ty<'tcx>) -> bool {
// check if *any* of those are trivial.
ty::Tuple(ref tys) => tys.iter().all(|t| trivial_dropck_outlives(tcx, t.expect_ty())),
ty::Closure(_, ref substs) => {
substs.as_closure().upvar_tys().all(|t| trivial_dropck_outlives(tcx, t))
trivial_dropck_outlives(tcx, substs.as_closure().tupled_upvars_ty())
}
ty::Adt(def, _) => {

34
compiler/rustc_trait_selection/src/traits/select/mod.rs
View file

@ -1631,7 +1631,13 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
ty::Closure(_, substs) => {
// (*) binder moved here
Where(ty::Binder::bind(substs.as_closure().upvar_tys().collect()))
let ty = self.infcx.shallow_resolve(substs.as_closure().tupled_upvars_ty());
if let ty::Infer(ty::TyVar(_)) = ty.kind() {
// Not yet resolved.
Ambiguous
} else {
Where(ty::Binder::bind(substs.as_closure().upvar_tys().collect()))
}
}
ty::Adt(..) | ty::Projection(..) | ty::Param(..) | ty::Opaque(..) => {
@ -1700,11 +1706,31 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
tys.iter().map(|k| k.expect_ty()).collect()
}
ty::Closure(_, ref substs) => substs.as_closure().upvar_tys().collect(),
ty::Closure(_, ref substs) => {
let ty = self.infcx.shallow_resolve(substs.as_closure().tupled_upvars_ty());
if let ty::Infer(ty::TyVar(_)) = ty.kind() {
// The inference variable will be replaced by a tuple once capture analysis
// completes. If the tuple meets a bound, so do all the elements within it.
vec![ty]
} else {
substs.as_closure().upvar_tys().collect()
}
}
ty::Generator(_, ref substs, _) => {
let witness = substs.as_generator().witness();
substs.as_generator().upvar_tys().chain(iter::once(witness)).collect()
let upvar_tys_resolved =
self.infcx.shallow_resolve(substs.as_generator().tupled_upvars_ty());
if let ty::Infer(ty::TyVar(_)) = upvar_tys_resolved.kind() {
// The inference variable will be replaced by a tuple once capture analysis
// completes, if the tuple meets a bound, so do all the elements within it.
let witness_resolved =
self.infcx.shallow_resolve(substs.as_generator().witness());
vec![upvar_tys_resolved, witness_resolved]
} else {
let witness = substs.as_generator().witness();
substs.as_generator().upvar_tys().chain(iter::once(witness)).collect()
}
}
ty::GeneratorWitness(types) => {

6
compiler/rustc_trait_selection/src/traits/wf.rs
View file

@ -592,10 +592,8 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
// anyway, except via auto trait matching (which
// only inspects the upvar types).
walker.skip_current_subtree(); // subtree handled below
for upvar_ty in substs.as_closure().upvar_tys() {
// FIXME(eddyb) add the type to `walker` instead of recursing.
self.compute(upvar_ty.into());
}
// FIXME(eddyb) add the type to `walker` instead of recursing.
self.compute(substs.as_closure().tupled_upvars_ty().into());
}
ty::FnPtr(_) => {