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Rename ~const Drop to ~const Destruct

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This commit is contained in:
Deadbeef 2022-03-21 16:52:41 +11:00
parent 4df2a28aee
commit 1f3ee7f32e
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GPG key ID: 6D017A96D8E6C2F9
32 changed files with 296 additions and 192 deletions
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4
compiler/rustc_trait_selection/src/traits/project.rs
View file

@ -1569,7 +1569,7 @@ fn assemble_candidates_from_impls<'cx, 'tcx>(
super::ImplSource::AutoImpl(..)
| super::ImplSource::Builtin(..)
| super::ImplSource::TraitUpcasting(_)
| super::ImplSource::ConstDrop(_) => {
| super::ImplSource::ConstDestruct(_) => {
// These traits have no associated types.
selcx.tcx().sess.delay_span_bug(
obligation.cause.span,
@ -1644,7 +1644,7 @@ fn confirm_select_candidate<'cx, 'tcx>(
| super::ImplSource::Builtin(..)
| super::ImplSource::TraitUpcasting(_)
| super::ImplSource::TraitAlias(..)
| super::ImplSource::ConstDrop(_) => {
| super::ImplSource::ConstDestruct(_) => {
// we don't create Select candidates with this kind of resolution
span_bug!(
obligation.cause.span,

32
compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
View file

@ -5,6 +5,7 @@
//! candidates. See the [rustc dev guide] for more details.
//!
//! [rustc dev guide]:https://rustc-dev-guide.rust-lang.org/traits/resolution.html#candidate-assembly
use hir::LangItem;
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_infer::traits::TraitEngine;
@ -307,7 +308,16 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
} else if lang_items.drop_trait() == Some(def_id)
&& obligation.predicate.is_const_if_const()
{
self.assemble_const_drop_candidates(obligation, &mut candidates);
// holds to make it easier to transition
// FIXME(fee1-dead): add a note for selection error of `~const Drop`
// when beta is bumped
// FIXME: remove this when beta is bumped
#[cfg(bootstrap)]
{}
candidates.vec.push(SelectionCandidate::ConstDestructCandidate(None))
} else if lang_items.destruct_trait() == Some(def_id) {
self.assemble_const_destruct_candidates(obligation, &mut candidates);
} else {
if lang_items.clone_trait() == Some(def_id) {
// Same builtin conditions as `Copy`, i.e., every type which has builtin support
@ -906,15 +916,15 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
}
fn assemble_const_drop_candidates(
fn assemble_const_destruct_candidates(
&mut self,
obligation: &TraitObligation<'tcx>,
candidates: &mut SelectionCandidateSet<'tcx>,
) {
// If the predicate is `~const Drop` in a non-const environment, we don't actually need
// If the predicate is `~const Destruct` in a non-const environment, we don't actually need
// to check anything. We'll short-circuit checking any obligations in confirmation, too.
if obligation.param_env.constness() == hir::Constness::NotConst {
candidates.vec.push(ConstDropCandidate(None));
if !obligation.is_const() {
candidates.vec.push(ConstDestructCandidate(None));
return;
}
@ -927,7 +937,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
| ty::Param(_)
| ty::Placeholder(_)
| ty::Projection(_) => {
// We don't know if these are `~const Drop`, at least
// We don't know if these are `~const Destruct`, at least
// not structurally... so don't push a candidate.
}
@ -951,14 +961,14 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
| ty::Generator(..)
| ty::Tuple(_)
| ty::GeneratorWitness(_) => {
// These are built-in, and cannot have a custom `impl const Drop`.
candidates.vec.push(ConstDropCandidate(None));
// These are built-in, and cannot have a custom `impl const Destruct`.
candidates.vec.push(ConstDestructCandidate(None));
}
ty::Adt(..) => {
// Find a custom `impl Drop` impl, if it exists
let relevant_impl = self.tcx().find_map_relevant_impl(
obligation.predicate.def_id(),
self.tcx().require_lang_item(LangItem::Drop, None),
obligation.predicate.skip_binder().trait_ref.self_ty(),
Some,
);
@ -966,11 +976,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
if let Some(impl_def_id) = relevant_impl {
// Check that `impl Drop` is actually const, if there is a custom impl
if self.tcx().impl_constness(impl_def_id) == hir::Constness::Const {
candidates.vec.push(ConstDropCandidate(Some(impl_def_id)));
candidates.vec.push(ConstDestructCandidate(Some(impl_def_id)));
}
} else {
// Otherwise check the ADT like a built-in type (structurally)
candidates.vec.push(ConstDropCandidate(None));
candidates.vec.push(ConstDestructCandidate(None));
}
}

60
compiler/rustc_trait_selection/src/traits/select/confirmation.rs
View file

@ -8,7 +8,6 @@
//! https://rustc-dev-guide.rust-lang.org/traits/resolution.html#confirmation
use rustc_data_structures::stack::ensure_sufficient_stack;
use rustc_hir::lang_items::LangItem;
use rustc_hir::Constness;
use rustc_index::bit_set::GrowableBitSet;
use rustc_infer::infer::InferOk;
use rustc_infer::infer::LateBoundRegionConversionTime::HigherRankedType;
@ -29,9 +28,9 @@ use crate::traits::TraitNotObjectSafe;
use crate::traits::VtblSegment;
use crate::traits::{BuiltinDerivedObligation, ImplDerivedObligation};
use crate::traits::{
ImplSourceAutoImplData, ImplSourceBuiltinData, ImplSourceClosureData, ImplSourceConstDropData,
ImplSourceDiscriminantKindData, ImplSourceFnPointerData, ImplSourceGeneratorData,
ImplSourceObjectData, ImplSourcePointeeData, ImplSourceTraitAliasData,
ImplSourceAutoImplData, ImplSourceBuiltinData, ImplSourceClosureData,
ImplSourceConstDestructData, ImplSourceDiscriminantKindData, ImplSourceFnPointerData,
ImplSourceGeneratorData, ImplSourceObjectData, ImplSourcePointeeData, ImplSourceTraitAliasData,
ImplSourceTraitUpcastingData, ImplSourceUserDefinedData,
};
use crate::traits::{ObjectCastObligation, PredicateObligation, TraitObligation};
@ -156,9 +155,9 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
Ok(ImplSource::TraitUpcasting(data))
}
ConstDropCandidate(def_id) => {
let data = self.confirm_const_drop_candidate(obligation, def_id)?;
Ok(ImplSource::ConstDrop(data))
ConstDestructCandidate(def_id) => {
let data = self.confirm_const_destruct_candidate(obligation, def_id)?;
Ok(ImplSource::ConstDestruct(data))
}
}
}
@ -1037,14 +1036,24 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
Ok(ImplSourceBuiltinData { nested })
}
fn confirm_const_drop_candidate(
fn confirm_const_destruct_candidate(
&mut self,
obligation: &TraitObligation<'tcx>,
impl_def_id: Option<DefId>,
) -> Result<ImplSourceConstDropData<PredicateObligation<'tcx>>, SelectionError<'tcx>> {
// `~const Drop` in a non-const environment is always trivially true, since our type is `Drop`
if obligation.param_env.constness() == Constness::NotConst {
return Ok(ImplSourceConstDropData { nested: vec![] });
) -> Result<ImplSourceConstDestructData<PredicateObligation<'tcx>>, SelectionError<'tcx>> {
// `~const Destruct` in a non-const environment is always trivially true, since our type is `Drop`
if !obligation.is_const() {
return Ok(ImplSourceConstDestructData { nested: vec![] });
}
let drop_trait = self.tcx().require_lang_item(LangItem::Drop, None);
// FIXME: remove if statement below when beta is bumped
#[cfg(bootstrap)]
{}
if obligation.predicate.skip_binder().def_id() == drop_trait
{
return Ok(ImplSourceConstDestructData { nested: vec![] });
}
let tcx = self.tcx();
@ -1054,9 +1063,26 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let cause = obligation.derived_cause(BuiltinDerivedObligation);
// If we have a custom `impl const Drop`, then
// first check it like a regular impl candidate
// first check it like a regular impl candidate.
// This is copied from confirm_impl_candidate but remaps the predicate to `~const Drop` beforehand.
if let Some(impl_def_id) = impl_def_id {
nested.extend(self.confirm_impl_candidate(obligation, impl_def_id).nested);
let obligations = self.infcx.commit_unconditionally(|_| {
let mut new_obligation = obligation.clone();
new_obligation.predicate = new_obligation.predicate.map_bound(|mut trait_pred| { trait_pred.trait_ref.def_id = drop_trait; trait_pred });
let substs = self.rematch_impl(impl_def_id, &new_obligation);
debug!(?substs, "impl substs");
let cause = obligation.derived_cause(ImplDerivedObligation);
ensure_sufficient_stack(|| {
self.vtable_impl(
impl_def_id,
substs,
cause,
new_obligation.recursion_depth + 1,
new_obligation.param_env,
)
})
});
nested.extend(obligations.nested);
}
// We want to confirm the ADT's fields if we have an ADT
@ -1114,7 +1140,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
self_ty
.rebind(ty::TraitPredicate {
trait_ref: ty::TraitRef {
def_id: self.tcx().require_lang_item(LangItem::Drop, None),
def_id: self.tcx().require_lang_item(LangItem::Destruct, None),
substs: self.tcx().mk_substs_trait(nested_ty, &[]),
},
constness: ty::BoundConstness::ConstIfConst,
@ -1140,7 +1166,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let predicate = self_ty
.rebind(ty::TraitPredicate {
trait_ref: ty::TraitRef {
def_id: self.tcx().require_lang_item(LangItem::Drop, None),
def_id: self.tcx().require_lang_item(LangItem::Destruct, None),
substs: self.tcx().mk_substs_trait(nested_ty, &[]),
},
constness: ty::BoundConstness::ConstIfConst,
@ -1158,6 +1184,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
}
Ok(ImplSourceConstDropData { nested })
Ok(ImplSourceConstDestructData { nested })
}
}

8
compiler/rustc_trait_selection/src/traits/select/mod.rs
View file

@ -1179,7 +1179,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
GeneratorCandidate => {}
// FnDef where the function is const
FnPointerCandidate { is_const: true } => {}
ConstDropCandidate(_) => {}
ConstDestructCandidate(_) => {}
_ => {
// reject all other types of candidates
continue;
@ -1589,7 +1589,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
};
// (*) Prefer `BuiltinCandidate { has_nested: false }`, `PointeeCandidate`,
// `DiscriminantKindCandidate`, and `ConstDropCandidate` to anything else.
// `DiscriminantKindCandidate`, and `ConstDestructCandidate` to anything else.
//
// This is a fix for #53123 and prevents winnowing from accidentally extending the
// lifetime of a variable.
@ -1606,7 +1606,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
BuiltinCandidate { has_nested: false }
| DiscriminantKindCandidate
| PointeeCandidate
| ConstDropCandidate(_),
| ConstDestructCandidate(_),
_,
) => true,
(
@ -1614,7 +1614,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
BuiltinCandidate { has_nested: false }
| DiscriminantKindCandidate
| PointeeCandidate
| ConstDropCandidate(_),
| ConstDestructCandidate(_),
) => false,
(ParamCandidate(other), ParamCandidate(victim)) => {