Auto merge of #118120 - compiler-errors:closure-kind, r=lcnr

Remove `PredicateKind::ClosureKind`

We don't need the `ClosureKind` predicate kind -- instead, `Fn`-family trait goals are left as ambiguous, and we only need to make progress on `FnOnce` projection goals for inference purposes.

This is similar to how we do confirmation of `Fn`-family trait and projection goals in the new trait solver, which also doesn't use the `ClosureKind` predicate.

Some hacky logic is added in the second commit so that we can keep the error messages the same.
This commit is contained in:
bors 2023-11-22 21:09:01 +00:00
commit 1e9dda77b5
19 changed files with 53 additions and 102 deletions

View File

@ -662,7 +662,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
// this closure yet; this is exactly why the other
// code is looking for a self type of an unresolved
// inference variable.
| ty::PredicateKind::ClosureKind(..)
| ty::PredicateKind::Ambiguous
=> None,
},

View File

@ -906,12 +906,14 @@ impl<'tcx> InferCtxt<'tcx> {
self.inner.borrow().undo_log.opaque_types_in_snapshot(&snapshot.undo_snapshot)
}
pub fn can_sub<T>(&self, param_env: ty::ParamEnv<'tcx>, a: T, b: T) -> bool
pub fn can_sub<T>(&self, param_env: ty::ParamEnv<'tcx>, expected: T, actual: T) -> bool
where
T: at::ToTrace<'tcx>,
{
let origin = &ObligationCause::dummy();
self.probe(|_| self.at(origin, param_env).sub(DefineOpaqueTypes::No, a, b).is_ok())
self.probe(|_| {
self.at(origin, param_env).sub(DefineOpaqueTypes::No, expected, actual).is_ok()
})
}
pub fn can_eq<T>(&self, param_env: ty::ParamEnv<'tcx>, a: T, b: T) -> bool

View File

@ -308,9 +308,6 @@ impl<'tcx, O: Elaboratable<'tcx>> Elaborator<'tcx, O> {
ty::PredicateKind::Clause(ty::ClauseKind::Projection(..)) => {
// Nothing to elaborate in a projection predicate.
}
ty::PredicateKind::ClosureKind(..) => {
// Nothing to elaborate when waiting for a closure's kind to be inferred.
}
ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..)) => {
// Currently, we do not elaborate const-evaluatable
// predicates.

View File

@ -263,9 +263,6 @@ impl FlagComputation {
self.add_args(slice::from_ref(&arg));
}
ty::PredicateKind::ObjectSafe(_def_id) => {}
ty::PredicateKind::ClosureKind(_def_id, args, _kind) => {
self.add_args(args);
}
ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(uv)) => {
self.add_const(uv);
}

View File

@ -548,7 +548,6 @@ impl<'tcx> Predicate<'tcx> {
| PredicateKind::Clause(ClauseKind::ConstArgHasType(..))
| PredicateKind::AliasRelate(..)
| PredicateKind::ObjectSafe(_)
| PredicateKind::ClosureKind(_, _, _)
| PredicateKind::Subtype(_)
| PredicateKind::Coerce(_)
| PredicateKind::Clause(ClauseKind::ConstEvaluatable(_))
@ -1276,7 +1275,6 @@ impl<'tcx> Predicate<'tcx> {
| PredicateKind::Clause(ClauseKind::RegionOutlives(..))
| PredicateKind::Clause(ClauseKind::WellFormed(..))
| PredicateKind::ObjectSafe(..)
| PredicateKind::ClosureKind(..)
| PredicateKind::Clause(ClauseKind::TypeOutlives(..))
| PredicateKind::Clause(ClauseKind::ConstEvaluatable(..))
| PredicateKind::ConstEquate(..)
@ -1296,7 +1294,6 @@ impl<'tcx> Predicate<'tcx> {
| PredicateKind::Clause(ClauseKind::RegionOutlives(..))
| PredicateKind::Clause(ClauseKind::WellFormed(..))
| PredicateKind::ObjectSafe(..)
| PredicateKind::ClosureKind(..)
| PredicateKind::Clause(ClauseKind::TypeOutlives(..))
| PredicateKind::Clause(ClauseKind::ConstEvaluatable(..))
| PredicateKind::ConstEquate(..)
@ -1317,7 +1314,6 @@ impl<'tcx> Predicate<'tcx> {
| PredicateKind::Clause(ClauseKind::RegionOutlives(..))
| PredicateKind::Clause(ClauseKind::WellFormed(..))
| PredicateKind::ObjectSafe(..)
| PredicateKind::ClosureKind(..)
| PredicateKind::Clause(ClauseKind::ConstEvaluatable(..))
| PredicateKind::ConstEquate(..)
| PredicateKind::Ambiguous => None,

View File

@ -2781,11 +2781,6 @@ define_print! {
ty::PredicateKind::ObjectSafe(trait_def_id) => {
p!("the trait `", print_def_path(trait_def_id, &[]), "` is object-safe")
}
ty::PredicateKind::ClosureKind(closure_def_id, _closure_args, kind) => p!(
"the closure `",
print_value_path(closure_def_id, &[]),
write("` implements the trait `{}`", kind)
),
ty::PredicateKind::ConstEquate(c1, c2) => {
p!("the constant `", print(c1), "` equals `", print(c2), "`")
}

View File

@ -1809,13 +1809,6 @@ impl<'tcx> Stable<'tcx> for ty::PredicateKind<'tcx> {
PredicateKind::ObjectSafe(did) => {
stable_mir::ty::PredicateKind::ObjectSafe(tables.trait_def(*did))
}
PredicateKind::ClosureKind(did, generic_args, closure_kind) => {
stable_mir::ty::PredicateKind::ClosureKind(
tables.closure_def(*did),
generic_args.stable(tables),
closure_kind.stable(tables),
)
}
PredicateKind::Subtype(subtype_predicate) => {
stable_mir::ty::PredicateKind::SubType(subtype_predicate.stable(tables))
}

View File

@ -406,8 +406,6 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
ty::PredicateKind::Coerce(predicate) => {
self.compute_coerce_goal(Goal { param_env, predicate })
}
ty::PredicateKind::ClosureKind(def_id, args, kind) => self
.compute_closure_kind_goal(Goal { param_env, predicate: (def_id, args, kind) }),
ty::PredicateKind::ObjectSafe(trait_def_id) => {
self.compute_object_safe_goal(trait_def_id)
}

View File

@ -135,7 +135,6 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
}
ty::PredicateKind::Clause(_)
| ty::PredicateKind::ObjectSafe(_)
| ty::PredicateKind::ClosureKind(_, _, _)
| ty::PredicateKind::Ambiguous => {
FulfillmentErrorCode::CodeSelectionError(
SelectionError::Unimplemented,

View File

@ -822,7 +822,6 @@ impl<'tcx> AutoTraitFinder<'tcx> {
| ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(..))
| ty::PredicateKind::AliasRelate(..)
| ty::PredicateKind::ObjectSafe(..)
| ty::PredicateKind::ClosureKind(..)
| ty::PredicateKind::Subtype(..)
// FIXME(generic_const_exprs): you can absolutely add this as a where clauses
| ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..))

View File

@ -98,6 +98,12 @@ pub trait TypeErrCtxtExt<'tcx> {
error: &SelectionError<'tcx>,
);
fn emit_specialized_closure_kind_error(
&self,
obligation: &PredicateObligation<'tcx>,
trait_ref: ty::PolyTraitRef<'tcx>,
) -> Option<ErrorGuaranteed>;
fn fn_arg_obligation(&self, obligation: &PredicateObligation<'tcx>) -> bool;
fn report_const_param_not_wf(
@ -411,6 +417,11 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
ty::PredicateKind::Clause(ty::ClauseKind::Trait(trait_predicate)) => {
let trait_predicate = bound_predicate.rebind(trait_predicate);
let trait_predicate = self.resolve_vars_if_possible(trait_predicate);
let trait_ref = trait_predicate.to_poly_trait_ref();
if let Some(_guar) = self.emit_specialized_closure_kind_error(&obligation, trait_ref) {
return;
}
// FIXME(effects)
let predicate_is_const = false;
@ -425,7 +436,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
// reported on the binding definition (#56607).
return;
}
let trait_ref = trait_predicate.to_poly_trait_ref();
let (post_message, pre_message, type_def, file_note) = self
.get_parent_trait_ref(obligation.cause.code())
.map(|(t, s)| {
@ -786,11 +796,6 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
report_object_safety_error(self.tcx, span, trait_def_id, violations)
}
ty::PredicateKind::ClosureKind(closure_def_id, closure_args, kind) => {
let found_kind = self.closure_kind(closure_args).unwrap();
self.report_closure_error(&obligation, closure_def_id, found_kind, kind)
}
ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(ty)) => {
let ty = self.resolve_vars_if_possible(ty);
match self.tcx.sess.opts.unstable_opts.trait_solver {
@ -927,6 +932,38 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
err.emit();
}
fn emit_specialized_closure_kind_error(
&self,
obligation: &PredicateObligation<'tcx>,
trait_ref: ty::PolyTraitRef<'tcx>,
) -> Option<ErrorGuaranteed> {
if let ty::Closure(closure_def_id, closure_args) = *trait_ref.self_ty().skip_binder().kind()
&& let Some(expected_kind) = self.tcx.fn_trait_kind_from_def_id(trait_ref.def_id())
&& let Some(found_kind) = self.closure_kind(closure_args)
&& !found_kind.extends(expected_kind)
&& let sig = closure_args.as_closure().sig()
&& self.can_sub(
obligation.param_env,
trait_ref,
sig.map_bound(|sig| {
ty::TraitRef::new(
self.tcx,
trait_ref.def_id(),
[trait_ref.self_ty().skip_binder(), sig.inputs()[0]],
)
}),
)
{
let mut err =
self.report_closure_error(&obligation, closure_def_id, found_kind, expected_kind);
self.note_obligation_cause(&mut err, &obligation);
self.point_at_returns_when_relevant(&mut err, &obligation);
Some(err.emit())
} else {
None
}
}
fn fn_arg_obligation(&self, obligation: &PredicateObligation<'tcx>) -> bool {
if let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } =
obligation.cause.code()

View File

@ -350,7 +350,6 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
| ty::PredicateKind::Clause(ty::ClauseKind::ConstArgHasType(..))
| ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(_))
| ty::PredicateKind::ObjectSafe(_)
| ty::PredicateKind::ClosureKind(..)
| ty::PredicateKind::Subtype(_)
| ty::PredicateKind::Coerce(_)
| ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..))
@ -411,19 +410,6 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> {
}
}
ty::PredicateKind::ClosureKind(_, closure_args, kind) => {
match self.selcx.infcx.closure_kind(closure_args) {
Some(closure_kind) => {
if closure_kind.extends(kind) {
ProcessResult::Changed(vec![])
} else {
ProcessResult::Error(CodeSelectionError(Unimplemented))
}
}
None => ProcessResult::Unchanged,
}
}
ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(arg)) => {
match wf::obligations(
self.selcx.infcx,

View File

@ -130,7 +130,6 @@ pub fn compute_implied_outlives_bounds_inner<'tcx>(
| ty::PredicateKind::Subtype(..)
| ty::PredicateKind::Coerce(..)
| ty::PredicateKind::Clause(ty::ClauseKind::Projection(..))
| ty::PredicateKind::ClosureKind(..)
| ty::PredicateKind::ObjectSafe(..)
| ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..))
| ty::PredicateKind::ConstEquate(..)

View File

@ -288,8 +288,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
}
None => {
debug!("assemble_unboxed_candidates: closure_kind not yet known");
candidates.vec.push(ClosureCandidate { is_const });
if kind == ty::ClosureKind::FnOnce {
candidates.vec.push(ClosureCandidate { is_const });
} else {
candidates.ambiguous = true;
}
}
}
}

View File

@ -821,11 +821,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
&mut self,
obligation: &PolyTraitObligation<'tcx>,
) -> Result<Vec<PredicateObligation<'tcx>>, SelectionError<'tcx>> {
let kind = self
.tcx()
.fn_trait_kind_from_def_id(obligation.predicate.def_id())
.unwrap_or_else(|| bug!("closure candidate for non-fn trait {:?}", obligation));
// Okay to skip binder because the args on closure types never
// touch bound regions, they just capture the in-scope
// type/region parameters.
@ -835,15 +830,10 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
};
let trait_ref = self.closure_trait_ref_unnormalized(obligation, args);
let mut nested = self.confirm_poly_trait_refs(obligation, trait_ref)?;
let nested = self.confirm_poly_trait_refs(obligation, trait_ref)?;
debug!(?closure_def_id, ?trait_ref, ?nested, "confirm closure candidate obligations");
nested.push(obligation.with(
self.tcx(),
ty::Binder::dummy(ty::PredicateKind::ClosureKind(closure_def_id, args, kind)),
));
Ok(nested)
}

View File

@ -885,19 +885,6 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
}
ty::PredicateKind::ClosureKind(_, closure_args, kind) => {
match self.infcx.closure_kind(closure_args) {
Some(closure_kind) => {
if closure_kind.extends(kind) {
Ok(EvaluatedToOk)
} else {
Ok(EvaluatedToErr)
}
}
None => Ok(EvaluatedToAmbig),
}
}
ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(uv)) => {
match const_evaluatable::is_const_evaluatable(
self.infcx,

View File

@ -58,7 +58,6 @@ fn not_outlives_predicate(p: ty::Predicate<'_>) -> bool {
| ty::PredicateKind::AliasRelate(..)
| ty::PredicateKind::Clause(ty::ClauseKind::WellFormed(..))
| ty::PredicateKind::ObjectSafe(..)
| ty::PredicateKind::ClosureKind(..)
| ty::PredicateKind::Subtype(..)
| ty::PredicateKind::Coerce(..)
| ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..))

View File

@ -129,11 +129,6 @@ pub enum PredicateKind<I: Interner> {
/// Trait must be object-safe.
ObjectSafe(I::DefId),
/// No direct syntax. May be thought of as `where T: FnFoo<...>`
/// for some generic args `...` and `T` being a closure type.
/// Satisfied (or refuted) once we know the closure's kind.
ClosureKind(I::DefId, I::GenericArgs, I::ClosureKind),
/// `T1 <: T2`
///
/// This obligation is created most often when we have two
@ -173,7 +168,6 @@ where
I::Term: Copy,
I::CoercePredicate: Copy,
I::SubtypePredicate: Copy,
I::ClosureKind: Copy,
ClauseKind<I>: Copy,
{
}
@ -183,9 +177,6 @@ impl<I: Interner> PartialEq for PredicateKind<I> {
match (self, other) {
(Self::Clause(l0), Self::Clause(r0)) => l0 == r0,
(Self::ObjectSafe(l0), Self::ObjectSafe(r0)) => l0 == r0,
(Self::ClosureKind(l0, l1, l2), Self::ClosureKind(r0, r1, r2)) => {
l0 == r0 && l1 == r1 && l2 == r2
}
(Self::Subtype(l0), Self::Subtype(r0)) => l0 == r0,
(Self::Coerce(l0), Self::Coerce(r0)) => l0 == r0,
(Self::ConstEquate(l0, l1), Self::ConstEquate(r0, r1)) => l0 == r0 && l1 == r1,
@ -207,18 +198,12 @@ where
I::Term: TypeFoldable<I>,
I::CoercePredicate: TypeFoldable<I>,
I::SubtypePredicate: TypeFoldable<I>,
I::ClosureKind: TypeFoldable<I>,
ClauseKind<I>: TypeFoldable<I>,
{
fn try_fold_with<F: FallibleTypeFolder<I>>(self, folder: &mut F) -> Result<Self, F::Error> {
Ok(match self {
PredicateKind::Clause(c) => PredicateKind::Clause(c.try_fold_with(folder)?),
PredicateKind::ObjectSafe(d) => PredicateKind::ObjectSafe(d.try_fold_with(folder)?),
PredicateKind::ClosureKind(d, g, k) => PredicateKind::ClosureKind(
d.try_fold_with(folder)?,
g.try_fold_with(folder)?,
k.try_fold_with(folder)?,
),
PredicateKind::Subtype(s) => PredicateKind::Subtype(s.try_fold_with(folder)?),
PredicateKind::Coerce(s) => PredicateKind::Coerce(s.try_fold_with(folder)?),
PredicateKind::ConstEquate(a, b) => {
@ -242,18 +227,12 @@ where
I::Term: TypeVisitable<I>,
I::CoercePredicate: TypeVisitable<I>,
I::SubtypePredicate: TypeVisitable<I>,
I::ClosureKind: TypeVisitable<I>,
ClauseKind<I>: TypeVisitable<I>,
{
fn visit_with<V: TypeVisitor<I>>(&self, visitor: &mut V) -> ControlFlow<V::BreakTy> {
match self {
PredicateKind::Clause(p) => p.visit_with(visitor),
PredicateKind::ObjectSafe(d) => d.visit_with(visitor),
PredicateKind::ClosureKind(d, g, k) => {
d.visit_with(visitor)?;
g.visit_with(visitor)?;
k.visit_with(visitor)
}
PredicateKind::Subtype(s) => s.visit_with(visitor),
PredicateKind::Coerce(s) => s.visit_with(visitor),
PredicateKind::ConstEquate(a, b) => {
@ -313,9 +292,6 @@ impl<I: Interner> fmt::Debug for PredicateKind<I> {
PredicateKind::ObjectSafe(trait_def_id) => {
write!(f, "ObjectSafe({trait_def_id:?})")
}
PredicateKind::ClosureKind(closure_def_id, closure_args, kind) => {
write!(f, "ClosureKind({closure_def_id:?}, {closure_args:?}, {kind:?})")
}
PredicateKind::ConstEquate(c1, c2) => write!(f, "ConstEquate({c1:?}, {c2:?})"),
PredicateKind::Ambiguous => write!(f, "Ambiguous"),
PredicateKind::AliasRelate(t1, t2, dir) => {

View File

@ -767,7 +767,6 @@ pub struct GenericPredicates {
pub enum PredicateKind {
Clause(ClauseKind),
ObjectSafe(TraitDef),
ClosureKind(ClosureDef, GenericArgs, ClosureKind),
SubType(SubtypePredicate),
Coerce(CoercePredicate),
ConstEquate(Const, Const),