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Auto merge of #87375 - fee1-dead:move-constness-to-traitpred, r=oli-obk

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Try filtering out non-const impls when we expect const impls

**TL;DR**: Associated types on const impls are now bounded; we now disallow calling a const function with bounds when the specified type param only has a non-const impl.

r? `@oli-obk`
This commit is contained in:
bors 2021-08-14 12:06:34 +00:00
commit 136eaa1b25
68 changed files with 517 additions and 211 deletions
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23
compiler/rustc_hir/src/hir.rs
View File

@ -2751,6 +2751,15 @@ pub enum Constness {
NotConst,
}
impl fmt::Display for Constness {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(match *self {
Self::Const => "const",
Self::NotConst => "non-const",
})
}
}
#[derive(Copy, Clone, Encodable, Debug, HashStable_Generic)]
pub struct FnHeader {
pub unsafety: Unsafety,
@ -3252,8 +3261,13 @@ impl<'hir> Node<'hir> {
}
}
/// Returns `Constness::Const` when this node is a const fn/impl.
pub fn constness(&self) -> Constness {
/// Returns `Constness::Const` when this node is a const fn/impl/item,
///
/// HACK(fee1-dead): or an associated type in a trait. This works because
/// only typeck cares about const trait predicates, so although the predicates
/// query would return const predicates when it does not need to be const,
/// it wouldn't have any effect.
pub fn constness_for_typeck(&self) -> Constness {
match self {
Node::Item(Item {
kind: ItemKind::Fn(FnSig { header: FnHeader { constness, .. }, .. }, ..),
@ -3269,6 +3283,11 @@ impl<'hir> Node<'hir> {
})
| Node::Item(Item { kind: ItemKind::Impl(Impl { constness, .. }), .. }) => *constness,
Node::Item(Item { kind: ItemKind::Const(..), .. })
| Node::TraitItem(TraitItem { kind: TraitItemKind::Const(..), .. })
| Node::TraitItem(TraitItem { kind: TraitItemKind::Type(..), .. })
| Node::ImplItem(ImplItem { kind: ImplItemKind::Const(..), .. }) => Constness::Const,
_ => Constness::NotConst,
}
}

18
compiler/rustc_infer/src/traits/engine.rs
View File

@ -1,5 +1,6 @@
use crate::infer::InferCtxt;
use crate::traits::Obligation;
use rustc_hir as hir;
use rustc_hir::def_id::DefId;
use rustc_middle::ty::{self, ToPredicate, Ty, WithConstness};
@ -49,11 +50,28 @@ pub trait TraitEngine<'tcx>: 'tcx {
infcx: &InferCtxt<'_, 'tcx>,
) -> Result<(), Vec<FulfillmentError<'tcx>>>;
fn select_all_with_constness_or_error(
&mut self,
infcx: &InferCtxt<'_, 'tcx>,
_constness: hir::Constness,
) -> Result<(), Vec<FulfillmentError<'tcx>>> {
self.select_all_or_error(infcx)
}
fn select_where_possible(
&mut self,
infcx: &InferCtxt<'_, 'tcx>,
) -> Result<(), Vec<FulfillmentError<'tcx>>>;
// FIXME this should not provide a default body for chalk as chalk should be updated
fn select_with_constness_where_possible(
&mut self,
infcx: &InferCtxt<'_, 'tcx>,
_constness: hir::Constness,
) -> Result<(), Vec<FulfillmentError<'tcx>>> {
self.select_where_possible(infcx)
}
fn pending_obligations(&self) -> Vec<PredicateObligation<'tcx>>;
}

2
compiler/rustc_infer/src/traits/util.rs
View File

@ -124,7 +124,7 @@ impl Elaborator<'tcx> {
let bound_predicate = obligation.predicate.kind();
match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(data, _) => {
ty::PredicateKind::Trait(data) => {
// Get predicates declared on the trait.
let predicates = tcx.super_predicates_of(data.def_id());

2
compiler/rustc_lint/src/traits.rs
View File

@ -87,7 +87,7 @@ impl<'tcx> LateLintPass<'tcx> for DropTraitConstraints {
let predicates = cx.tcx.explicit_predicates_of(item.def_id);
for &(predicate, span) in predicates.predicates {
let trait_predicate = match predicate.kind().skip_binder() {
Trait(trait_predicate, _constness) => trait_predicate,
Trait(trait_predicate) => trait_predicate,
_ => continue,
};
let def_id = trait_predicate.trait_ref.def_id;

2
compiler/rustc_lint/src/unused.rs
View File

@ -211,7 +211,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedResults {
let mut has_emitted = false;
for &(predicate, _) in cx.tcx.explicit_item_bounds(def) {
// We only look at the `DefId`, so it is safe to skip the binder here.
if let ty::PredicateKind::Trait(ref poly_trait_predicate, _) =
if let ty::PredicateKind::Trait(ref poly_trait_predicate) =
predicate.kind().skip_binder()
{
let def_id = poly_trait_predicate.trait_ref.def_id;

4
compiler/rustc_middle/src/traits/select.rs
View File

@ -12,12 +12,12 @@ use rustc_hir::def_id::DefId;
use rustc_query_system::cache::Cache;
pub type SelectionCache<'tcx> = Cache<
ty::ParamEnvAnd<'tcx, ty::TraitRef<'tcx>>,
ty::ConstnessAnd<ty::ParamEnvAnd<'tcx, ty::TraitRef<'tcx>>>,
SelectionResult<'tcx, SelectionCandidate<'tcx>>,
>;
pub type EvaluationCache<'tcx> =
Cache<ty::ParamEnvAnd<'tcx, ty::PolyTraitRef<'tcx>>, EvaluationResult>;
Cache<ty::ParamEnvAnd<'tcx, ty::ConstnessAnd<ty::PolyTraitRef<'tcx>>>, EvaluationResult>;
/// The selection process begins by considering all impls, where
/// clauses, and so forth that might resolve an obligation. Sometimes

7
compiler/rustc_middle/src/ty/assoc.rs
View File

@ -16,6 +16,13 @@ pub enum AssocItemContainer {
}
impl AssocItemContainer {
pub fn impl_def_id(&self) -> Option<DefId> {
match *self {
ImplContainer(id) => Some(id),
_ => None,
}
}
/// Asserts that this is the `DefId` of an associated item declared
/// in a trait, and returns the trait `DefId`.
pub fn assert_trait(&self) -> DefId {

2
compiler/rustc_middle/src/ty/context.rs
View File

@ -2169,7 +2169,7 @@ impl<'tcx> TyCtxt<'tcx> {
let generic_predicates = self.super_predicates_of(trait_did);
for (predicate, _) in generic_predicates.predicates {
if let ty::PredicateKind::Trait(data, _) = predicate.kind().skip_binder() {
if let ty::PredicateKind::Trait(data) = predicate.kind().skip_binder() {
if set.insert(data.def_id()) {
stack.push(data.def_id());
}

12
compiler/rustc_middle/src/ty/error.rs
View File

@ -33,6 +33,7 @@ impl<T> ExpectedFound<T> {
#[derive(Clone, Debug, TypeFoldable)]
pub enum TypeError<'tcx> {
Mismatch,
ConstnessMismatch(ExpectedFound<hir::Constness>),
UnsafetyMismatch(ExpectedFound<hir::Unsafety>),
AbiMismatch(ExpectedFound<abi::Abi>),
Mutability,
@ -106,6 +107,9 @@ impl<'tcx> fmt::Display for TypeError<'tcx> {
CyclicTy(_) => write!(f, "cyclic type of infinite size"),
CyclicConst(_) => write!(f, "encountered a self-referencing constant"),
Mismatch => write!(f, "types differ"),
ConstnessMismatch(values) => {
write!(f, "expected {} fn, found {} fn", values.expected, values.found)
}
UnsafetyMismatch(values) => {
write!(f, "expected {} fn, found {} fn", values.expected, values.found)
}
@ -213,9 +217,11 @@ impl<'tcx> TypeError<'tcx> {
pub fn must_include_note(&self) -> bool {
use self::TypeError::*;
match self {
CyclicTy(_) | CyclicConst(_) | UnsafetyMismatch(_) | Mismatch | AbiMismatch(_)
| FixedArraySize(_) | ArgumentSorts(..) | Sorts(_) | IntMismatch(_)
| FloatMismatch(_) | VariadicMismatch(_) | TargetFeatureCast(_) => false,
CyclicTy(_) | CyclicConst(_) | UnsafetyMismatch(_) | ConstnessMismatch(_)
| Mismatch | AbiMismatch(_) | FixedArraySize(_) | ArgumentSorts(..) | Sorts(_)
| IntMismatch(_) | FloatMismatch(_) | VariadicMismatch(_) | TargetFeatureCast(_) => {
false
}
Mutability
| ArgumentMutability(_)

2
compiler/rustc_middle/src/ty/flags.rs
View File

@ -216,7 +216,7 @@ impl FlagComputation {
fn add_predicate_atom(&mut self, atom: ty::PredicateKind<'_>) {
match atom {
ty::PredicateKind::Trait(trait_pred, _constness) => {
ty::PredicateKind::Trait(trait_pred) => {
self.add_substs(trait_pred.trait_ref.substs);
}
ty::PredicateKind::RegionOutlives(ty::OutlivesPredicate(a, b)) => {

24
compiler/rustc_middle/src/ty/mod.rs
View File

@ -461,7 +461,7 @@ pub enum PredicateKind<'tcx> {
/// A trait predicate will have `Constness::Const` if it originates
/// from a bound on a `const fn` without the `?const` opt-out (e.g.,
/// `const fn foobar<Foo: Bar>() {}`).
Trait(TraitPredicate<'tcx>, Constness),
Trait(TraitPredicate<'tcx>),
/// `where 'a: 'b`
RegionOutlives(RegionOutlivesPredicate<'tcx>),
@ -617,6 +617,11 @@ impl<'tcx> Predicate<'tcx> {
#[derive(HashStable, TypeFoldable)]
pub struct TraitPredicate<'tcx> {
pub trait_ref: TraitRef<'tcx>,
/// A trait predicate will have `Constness::Const` if it originates
/// from a bound on a `const fn` without the `?const` opt-out (e.g.,
/// `const fn foobar<Foo: Bar>() {}`).
pub constness: hir::Constness,
}
pub type PolyTraitPredicate<'tcx> = ty::Binder<'tcx, TraitPredicate<'tcx>>;
@ -750,8 +755,11 @@ impl ToPredicate<'tcx> for PredicateKind<'tcx> {
impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<TraitRef<'tcx>> {
fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
PredicateKind::Trait(ty::TraitPredicate { trait_ref: self.value }, self.constness)
.to_predicate(tcx)
PredicateKind::Trait(ty::TraitPredicate {
trait_ref: self.value,
constness: self.constness,
})
.to_predicate(tcx)
}
}
@ -759,15 +767,15 @@ impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<PolyTraitRef<'tcx>> {
fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
self.value
.map_bound(|trait_ref| {
PredicateKind::Trait(ty::TraitPredicate { trait_ref }, self.constness)
PredicateKind::Trait(ty::TraitPredicate { trait_ref, constness: self.constness })
})
.to_predicate(tcx)
}
}
impl<'tcx> ToPredicate<'tcx> for ConstnessAnd<PolyTraitPredicate<'tcx>> {
impl<'tcx> ToPredicate<'tcx> for PolyTraitPredicate<'tcx> {
fn to_predicate(self, tcx: TyCtxt<'tcx>) -> Predicate<'tcx> {
self.value.map_bound(|value| PredicateKind::Trait(value, self.constness)).to_predicate(tcx)
self.map_bound(PredicateKind::Trait).to_predicate(tcx)
}
}
@ -793,8 +801,8 @@ impl<'tcx> Predicate<'tcx> {
pub fn to_opt_poly_trait_ref(self) -> Option<ConstnessAnd<PolyTraitRef<'tcx>>> {
let predicate = self.kind();
match predicate.skip_binder() {
PredicateKind::Trait(t, constness) => {
Some(ConstnessAnd { constness, value: predicate.rebind(t.trait_ref) })
PredicateKind::Trait(t) => {
Some(ConstnessAnd { constness: t.constness, value: predicate.rebind(t.trait_ref) })
}
PredicateKind::Projection(..)
| PredicateKind::Subtype(..)

7
compiler/rustc_middle/src/ty/print/pretty.rs
View File

@ -630,7 +630,7 @@ pub trait PrettyPrinter<'tcx>:
for (predicate, _) in bounds {
let predicate = predicate.subst(self.tcx(), substs);
let bound_predicate = predicate.kind();
if let ty::PredicateKind::Trait(pred, _) = bound_predicate.skip_binder() {
if let ty::PredicateKind::Trait(pred) = bound_predicate.skip_binder() {
let trait_ref = bound_predicate.rebind(pred.trait_ref);
// Don't print +Sized, but rather +?Sized if absent.
if Some(trait_ref.def_id()) == self.tcx().lang_items().sized_trait() {
@ -2264,10 +2264,7 @@ define_print_and_forward_display! {
ty::PredicateKind<'tcx> {
match *self {
ty::PredicateKind::Trait(ref data, constness) => {
if let hir::Constness::Const = constness {
p!("const ");
}
ty::PredicateKind::Trait(ref data) => {
p!(print(data))
}
ty::PredicateKind::Subtype(predicate) => p!(print(predicate)),

32
compiler/rustc_middle/src/ty/relate.rs
View File

@ -200,6 +200,33 @@ impl<'tcx> Relate<'tcx> for ty::FnSig<'tcx> {
}
}
impl<'tcx> Relate<'tcx> for ast::Constness {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: ast::Constness,
b: ast::Constness,
) -> RelateResult<'tcx, ast::Constness> {
if a != b {
Err(TypeError::ConstnessMismatch(expected_found(relation, a, b)))
} else {
Ok(a)
}
}
}
impl<'tcx, T: Relate<'tcx>> Relate<'tcx> for ty::ConstnessAnd<T> {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
a: ty::ConstnessAnd<T>,
b: ty::ConstnessAnd<T>,
) -> RelateResult<'tcx, ty::ConstnessAnd<T>> {
Ok(ty::ConstnessAnd {
constness: relation.relate(a.constness, b.constness)?,
value: relation.relate(a.value, b.value)?,
})
}
}
impl<'tcx> Relate<'tcx> for ast::Unsafety {
fn relate<R: TypeRelation<'tcx>>(
relation: &mut R,
@ -767,7 +794,10 @@ impl<'tcx> Relate<'tcx> for ty::TraitPredicate<'tcx> {
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)? })
Ok(ty::TraitPredicate {
trait_ref: relation.relate(a.trait_ref, b.trait_ref)?,
constness: relation.relate(a.constness, b.constness)?,
})
}
}

18
compiler/rustc_middle/src/ty/structural_impls.rs
View File

@ -155,6 +155,9 @@ impl fmt::Debug for ty::ParamConst {
impl fmt::Debug for ty::TraitPredicate<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
if let hir::Constness::Const = self.constness {
write!(f, "const ")?;
}
write!(f, "TraitPredicate({:?})", self.trait_ref)
}
}
@ -174,12 +177,7 @@ impl fmt::Debug for ty::Predicate<'tcx> {
impl fmt::Debug for ty::PredicateKind<'tcx> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match *self {
ty::PredicateKind::Trait(ref a, constness) => {
if let hir::Constness::Const = constness {
write!(f, "const ")?;
}
a.fmt(f)
}
ty::PredicateKind::Trait(ref a) => a.fmt(f),
ty::PredicateKind::Subtype(ref pair) => pair.fmt(f),
ty::PredicateKind::RegionOutlives(ref pair) => pair.fmt(f),
ty::PredicateKind::TypeOutlives(ref pair) => pair.fmt(f),
@ -366,7 +364,8 @@ impl<'a, 'tcx> Lift<'tcx> for ty::ExistentialPredicate<'a> {
impl<'a, 'tcx> Lift<'tcx> for ty::TraitPredicate<'a> {
type Lifted = ty::TraitPredicate<'tcx>;
fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<ty::TraitPredicate<'tcx>> {
tcx.lift(self.trait_ref).map(|trait_ref| ty::TraitPredicate { trait_ref })
tcx.lift(self.trait_ref)
.map(|trait_ref| ty::TraitPredicate { trait_ref, constness: self.constness })
}
}
@ -419,9 +418,7 @@ impl<'a, 'tcx> Lift<'tcx> for ty::PredicateKind<'a> {
type Lifted = ty::PredicateKind<'tcx>;
fn lift_to_tcx(self, tcx: TyCtxt<'tcx>) -> Option<Self::Lifted> {
match self {
ty::PredicateKind::Trait(data, constness) => {
tcx.lift(data).map(|data| ty::PredicateKind::Trait(data, constness))
}
ty::PredicateKind::Trait(data) => tcx.lift(data).map(ty::PredicateKind::Trait),
ty::PredicateKind::Subtype(data) => tcx.lift(data).map(ty::PredicateKind::Subtype),
ty::PredicateKind::RegionOutlives(data) => {
tcx.lift(data).map(ty::PredicateKind::RegionOutlives)
@ -584,6 +581,7 @@ impl<'a, 'tcx> Lift<'tcx> for ty::error::TypeError<'a> {
Some(match self {
Mismatch => Mismatch,
ConstnessMismatch(x) => ConstnessMismatch(x),
UnsafetyMismatch(x) => UnsafetyMismatch(x),
AbiMismatch(x) => AbiMismatch(x),
Mutability => Mutability,

5
compiler/rustc_middle/src/ty/sty.rs
View File

@ -876,7 +876,10 @@ impl<'tcx> PolyTraitRef<'tcx> {
}
pub fn to_poly_trait_predicate(&self) -> ty::PolyTraitPredicate<'tcx> {
self.map_bound(|trait_ref| ty::TraitPredicate { trait_ref })
self.map_bound(|trait_ref| ty::TraitPredicate {
trait_ref,
constness: hir::Constness::NotConst,
})
}
}

13
compiler/rustc_mir/src/borrow_check/type_check/mod.rs
View File

@ -1084,11 +1084,12 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
span_mirbug!(
self,
user_annotation,
"bad user type AscribeUserType({:?}, {:?} {:?}): {:?}",
"bad user type AscribeUserType({:?}, {:?} {:?}, type_of={:?}): {:?}",
inferred_ty,
def_id,
user_substs,
terr
self.tcx().type_of(def_id),
terr,
);
}
}
@ -2688,10 +2689,10 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
category: ConstraintCategory,
) {
self.prove_predicates(
Some(ty::PredicateKind::Trait(
ty::TraitPredicate { trait_ref },
hir::Constness::NotConst,
)),
Some(ty::PredicateKind::Trait(ty::TraitPredicate {
trait_ref,
constness: hir::Constness::NotConst,
})),
locations,
category,
);

7
compiler/rustc_mir/src/transform/check_consts/check.rs
View File

@ -423,7 +423,7 @@ impl Checker<'mir, 'tcx> {
ty::PredicateKind::Subtype(_) => {
bug!("subtype predicate on function: {:#?}", predicate)
}
ty::PredicateKind::Trait(pred, _constness) => {
ty::PredicateKind::Trait(pred) => {
if Some(pred.def_id()) == tcx.lang_items().sized_trait() {
continue;
}
@ -817,7 +817,10 @@ impl Visitor<'tcx> for Checker<'mir, 'tcx> {
let obligation = Obligation::new(
ObligationCause::dummy(),
param_env,
Binder::dummy(TraitPredicate { trait_ref }),
Binder::dummy(TraitPredicate {
trait_ref,
constness: hir::Constness::Const,
}),
);
let implsrc = tcx.infer_ctxt().enter(|infcx| {

2
compiler/rustc_mir/src/transform/function_item_references.rs
View File

@ -132,7 +132,7 @@ impl<'a, 'tcx> FunctionItemRefChecker<'a, 'tcx> {
/// If the given predicate is the trait `fmt::Pointer`, returns the bound parameter type.
fn is_pointer_trait(&self, bound: &PredicateKind<'tcx>) -> Option<Ty<'tcx>> {
if let ty::PredicateKind::Trait(predicate, _) = bound {
if let ty::PredicateKind::Trait(predicate) = bound {
if self.tcx.is_diagnostic_item(sym::pointer_trait, predicate.def_id()) {
Some(predicate.trait_ref.self_ty())
} else {

2
compiler/rustc_privacy/src/lib.rs
View File

@ -122,7 +122,7 @@ where
fn visit_predicate(&mut self, predicate: ty::Predicate<'tcx>) -> ControlFlow<V::BreakTy> {
match predicate.kind().skip_binder() {
ty::PredicateKind::Trait(ty::TraitPredicate { trait_ref }, _) => {
ty::PredicateKind::Trait(ty::TraitPredicate { trait_ref, constness: _ }) => {
self.visit_trait(trait_ref)
}
ty::PredicateKind::Projection(ty::ProjectionPredicate { projection_ty, ty }) => {

2
compiler/rustc_resolve/src/late/lifetimes.rs
View File

@ -2657,7 +2657,7 @@ impl<'a, 'tcx> LifetimeContext<'a, 'tcx> {
let obligations = predicates.predicates.iter().filter_map(|&(pred, _)| {
let bound_predicate = pred.kind();
match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(data, _) => {
ty::PredicateKind::Trait(data) => {
// The order here needs to match what we would get from `subst_supertrait`
let pred_bound_vars = bound_predicate.bound_vars();
let mut all_bound_vars = bound_vars.clone();

14
compiler/rustc_trait_selection/src/traits/auto_trait.rs
View File

@ -285,6 +285,7 @@ impl AutoTraitFinder<'tcx> {
def_id: trait_did,
substs: infcx.tcx.mk_substs_trait(ty, &[]),
},
constness: hir::Constness::NotConst,
}));
let computed_preds = param_env.caller_bounds().iter();
@ -344,10 +345,7 @@ impl AutoTraitFinder<'tcx> {
Err(SelectionError::Unimplemented) => {
if self.is_param_no_infer(pred.skip_binder().trait_ref.substs) {
already_visited.remove(&pred);
self.add_user_pred(
&mut user_computed_preds,
pred.without_const().to_predicate(self.tcx),
);
self.add_user_pred(&mut user_computed_preds, pred.to_predicate(self.tcx));
predicates.push_back(pred);
} else {
debug!(
@ -414,10 +412,8 @@ impl AutoTraitFinder<'tcx> {
) {
let mut should_add_new = true;
user_computed_preds.retain(|&old_pred| {
if let (
ty::PredicateKind::Trait(new_trait, _),
ty::PredicateKind::Trait(old_trait, _),
) = (new_pred.kind().skip_binder(), old_pred.kind().skip_binder())
if let (ty::PredicateKind::Trait(new_trait), ty::PredicateKind::Trait(old_trait)) =
(new_pred.kind().skip_binder(), old_pred.kind().skip_binder())
{
if new_trait.def_id() == old_trait.def_id() {
let new_substs = new_trait.trait_ref.substs;
@ -638,7 +634,7 @@ impl AutoTraitFinder<'tcx> {
let bound_predicate = predicate.kind();
match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(p, _) => {
ty::PredicateKind::Trait(p) => {
// Add this to `predicates` so that we end up calling `select`
// with it. If this predicate ends up being unimplemented,
// then `evaluate_predicates` will handle adding it the `ParamEnv`

13
compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
View File

@ -277,7 +277,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
let bound_predicate = obligation.predicate.kind();
match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(trait_predicate, _) => {
ty::PredicateKind::Trait(trait_predicate) => {
let trait_predicate = bound_predicate.rebind(trait_predicate);
let trait_predicate = self.resolve_vars_if_possible(trait_predicate);
@ -518,8 +518,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
);
trait_pred
});
let unit_obligation =
obligation.with(predicate.without_const().to_predicate(tcx));
let unit_obligation = obligation.with(predicate.to_predicate(tcx));
if self.predicate_may_hold(&unit_obligation) {
err.note("this trait is implemented for `()`.");
err.note(
@ -1148,7 +1147,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
// FIXME: It should be possible to deal with `ForAll` in a cleaner way.
let bound_error = error.kind();
let (cond, error) = match (cond.kind().skip_binder(), bound_error.skip_binder()) {
(ty::PredicateKind::Trait(..), ty::PredicateKind::Trait(error, _)) => {
(ty::PredicateKind::Trait(..), ty::PredicateKind::Trait(error)) => {
(cond, bound_error.rebind(error))
}
_ => {
@ -1159,7 +1158,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
for obligation in super::elaborate_predicates(self.tcx, std::iter::once(cond)) {
let bound_predicate = obligation.predicate.kind();
if let ty::PredicateKind::Trait(implication, _) = bound_predicate.skip_binder() {
if let ty::PredicateKind::Trait(implication) = bound_predicate.skip_binder() {
let error = error.to_poly_trait_ref();
let implication = bound_predicate.rebind(implication.trait_ref);
// FIXME: I'm just not taking associated types at all here.
@ -1536,7 +1535,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
let bound_predicate = predicate.kind();
let mut err = match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(data, _) => {
ty::PredicateKind::Trait(data) => {
let trait_ref = bound_predicate.rebind(data.trait_ref);
debug!("trait_ref {:?}", trait_ref);
@ -1803,7 +1802,7 @@ impl<'a, 'tcx> InferCtxtPrivExt<'tcx> for InferCtxt<'a, 'tcx> {
match (obligation.predicate.kind().skip_binder(), obligation.cause.code.peel_derives())
{
(
ty::PredicateKind::Trait(pred, _),
ty::PredicateKind::Trait(pred),
&ObligationCauseCode::BindingObligation(item_def_id, span),
) => (pred, item_def_id, span),
_ => return,

2
compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
View File

@ -1386,7 +1386,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
// bound was introduced. At least one generator should be present for this diagnostic to be
// modified.
let (mut trait_ref, mut target_ty) = match obligation.predicate.kind().skip_binder() {
ty::PredicateKind::Trait(p, _) => (Some(p.trait_ref), Some(p.self_ty())),
ty::PredicateKind::Trait(p) => (Some(p.trait_ref), Some(p.self_ty())),
_ => (None, None),
};
let mut generator = None;

44
compiler/rustc_trait_selection/src/traits/fulfill.rs
View File

@ -3,6 +3,7 @@ use rustc_data_structures::obligation_forest::ProcessResult;
use rustc_data_structures::obligation_forest::{Error, ForestObligation, Outcome};
use rustc_data_structures::obligation_forest::{ObligationForest, ObligationProcessor};
use rustc_errors::ErrorReported;
use rustc_hir as hir;
use rustc_infer::traits::{SelectionError, TraitEngine, TraitEngineExt as _, TraitObligation};
use rustc_middle::mir::abstract_const::NotConstEvaluatable;
use rustc_middle::mir::interpret::ErrorHandled;
@ -228,6 +229,22 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> {
if errors.is_empty() { Ok(()) } else { Err(errors) }
}
fn select_all_with_constness_or_error(
&mut self,
infcx: &InferCtxt<'_, 'tcx>,
constness: rustc_hir::Constness,
) -> Result<(), Vec<FulfillmentError<'tcx>>> {
self.select_with_constness_where_possible(infcx, constness)?;
let errors: Vec<_> = self
.predicates
.to_errors(CodeAmbiguity)
.into_iter()
.map(to_fulfillment_error)
.collect();
if errors.is_empty() { Ok(()) } else { Err(errors) }
}
fn select_where_possible(
&mut self,
infcx: &InferCtxt<'_, 'tcx>,
@ -236,6 +253,15 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentContext<'tcx> {
self.select(&mut selcx)
}
fn select_with_constness_where_possible(
&mut self,
infcx: &InferCtxt<'_, 'tcx>,
constness: hir::Constness,
) -> Result<(), Vec<FulfillmentError<'tcx>>> {
let mut selcx = SelectionContext::with_constness(infcx, constness);
self.select(&mut selcx)
}
fn pending_obligations(&self) -> Vec<PredicateObligation<'tcx>> {
self.predicates.map_pending_obligations(|o| o.obligation.clone())
}
@ -352,7 +378,7 @@ impl<'a, 'b, 'tcx> FulfillProcessor<'a, 'b, 'tcx> {
// Evaluation will discard candidates using the leak check.
// This means we need to pass it the bound version of our
// predicate.
ty::PredicateKind::Trait(trait_ref, _constness) => {
ty::PredicateKind::Trait(trait_ref) => {
let trait_obligation = obligation.with(binder.rebind(trait_ref));
self.process_trait_obligation(
@ -388,7 +414,7 @@ impl<'a, 'b, 'tcx> FulfillProcessor<'a, 'b, 'tcx> {
}
},
Some(pred) => match pred {
ty::PredicateKind::Trait(data, _) => {
ty::PredicateKind::Trait(data) => {
let trait_obligation = obligation.with(Binder::dummy(data));
self.process_trait_obligation(
@ -623,7 +649,12 @@ impl<'a, 'b, 'tcx> FulfillProcessor<'a, 'b, 'tcx> {
if obligation.predicate.is_global() {
// no type variables present, can use evaluation for better caching.
// FIXME: consider caching errors too.
if infcx.predicate_must_hold_considering_regions(obligation) {
//
// If the predicate is considered const, then we cannot use this because
// it will cause false negatives in the ui tests.
if !self.selcx.is_predicate_const(obligation.predicate)
&& infcx.predicate_must_hold_considering_regions(obligation)
{
debug!(
"selecting trait at depth {} evaluated to holds",
obligation.recursion_depth
@ -677,7 +708,12 @@ impl<'a, 'b, 'tcx> FulfillProcessor<'a, 'b, 'tcx> {
if obligation.predicate.is_global() {
// no type variables present, can use evaluation for better caching.
// FIXME: consider caching errors too.
if self.selcx.infcx().predicate_must_hold_considering_regions(obligation) {
//
// If the predicate is considered const, then we cannot use this because
// it will cause false negatives in the ui tests.
if !self.selcx.is_predicate_const(obligation.predicate)
&& self.selcx.infcx().predicate_must_hold_considering_regions(obligation)
{
return ProcessResult::Changed(vec![]);
} else {
tracing::debug!("Does NOT hold: {:?}", obligation);

4
compiler/rustc_trait_selection/src/traits/object_safety.rs
View File

@ -280,7 +280,7 @@ fn predicate_references_self(
let self_ty = tcx.types.self_param;
let has_self_ty = |arg: &GenericArg<'_>| arg.walk().any(|arg| arg == self_ty.into());
match predicate.kind().skip_binder() {
ty::PredicateKind::Trait(ref data, _) => {
ty::PredicateKind::Trait(ref data) => {
// In the case of a trait predicate, we can skip the "self" type.
if data.trait_ref.substs[1..].iter().any(has_self_ty) { Some(sp) } else { None }
}
@ -331,7 +331,7 @@ fn generics_require_sized_self(tcx: TyCtxt<'_>, def_id: DefId) -> bool {
let predicates = predicates.instantiate_identity(tcx).predicates;
elaborate_predicates(tcx, predicates.into_iter()).any(|obligation| {
match obligation.predicate.kind().skip_binder() {
ty::PredicateKind::Trait(ref trait_pred, _) => {
ty::PredicateKind::Trait(ref trait_pred) => {
trait_pred.def_id() == sized_def_id && trait_pred.self_ty().is_param(0)
}
ty::PredicateKind::Projection(..)

2
compiler/rustc_trait_selection/src/traits/query/type_op/prove_predicate.rs
View File

@ -15,7 +15,7 @@ impl<'tcx> super::QueryTypeOp<'tcx> for ProvePredicate<'tcx> {
// `&T`, accounts for about 60% percentage of the predicates
// we have to prove. No need to canonicalize and all that for
// such cases.
if let ty::PredicateKind::Trait(trait_ref, _) = key.value.predicate.kind().skip_binder() {
if let ty::PredicateKind::Trait(trait_ref) = key.value.predicate.kind().skip_binder() {
if let Some(sized_def_id) = tcx.lang_items().sized_trait() {
if trait_ref.def_id() == sized_def_id {
if trait_ref.self_ty().is_trivially_sized(tcx) {

4
compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs
View File

@ -144,7 +144,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// Instead, we select the right impl now but report "`Bar` does
// not implement `Clone`".
if candidates.len() == 1 {
return self.filter_negative_and_reservation_impls(candidates.pop().unwrap());
return self.filter_impls(candidates.pop().unwrap(), stack.obligation);
}
// Winnow, but record the exact outcome of evaluation, which
@ -217,7 +217,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
}
// Just one candidate left.
self.filter_negative_and_reservation_impls(candidates.pop().unwrap().candidate)
self.filter_impls(candidates.pop().unwrap().candidate, stack.obligation)
}
pub(super) fn assemble_candidates<'o>(

139
compiler/rustc_trait_selection/src/traits/select/mod.rs
View File

@ -41,8 +41,9 @@ use rustc_middle::ty::fast_reject;
use rustc_middle::ty::print::with_no_trimmed_paths;
use rustc_middle::ty::relate::TypeRelation;
use rustc_middle::ty::subst::{GenericArgKind, Subst, SubstsRef};
use rustc_middle::ty::WithConstness;
use rustc_middle::ty::{self, PolyProjectionPredicate, ToPolyTraitRef, ToPredicate};
use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable, WithConstness};
use rustc_middle::ty::{Ty, TyCtxt, TypeFoldable};
use rustc_span::symbol::sym;
use std::cell::{Cell, RefCell};
@ -129,6 +130,9 @@ pub struct SelectionContext<'cx, 'tcx> {
/// and a negative impl
allow_negative_impls: bool,
/// Do we only want const impls when we have a const trait predicate?
const_impls_required: bool,
/// The mode that trait queries run in, which informs our error handling
/// policy. In essence, canonicalized queries need their errors propagated
/// rather than immediately reported because we do not have accurate spans.
@ -141,7 +145,7 @@ struct TraitObligationStack<'prev, 'tcx> {
/// The trait ref from `obligation` but "freshened" with the
/// selection-context's freshener. Used to check for recursion.
fresh_trait_ref: ty::PolyTraitRef<'tcx>,
fresh_trait_ref: ty::ConstnessAnd<ty::PolyTraitRef<'tcx>>,
/// Starts out equal to `depth` -- if, during evaluation, we
/// encounter a cycle, then we will set this flag to the minimum
@ -220,6 +224,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
intercrate: false,
intercrate_ambiguity_causes: None,
allow_negative_impls: false,
const_impls_required: false,
query_mode: TraitQueryMode::Standard,
}
}
@ -231,6 +236,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
intercrate: true,
intercrate_ambiguity_causes: None,
allow_negative_impls: false,
const_impls_required: false,
query_mode: TraitQueryMode::Standard,
}
}
@ -246,6 +252,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
intercrate: false,
intercrate_ambiguity_causes: None,
allow_negative_impls,
const_impls_required: false,
query_mode: TraitQueryMode::Standard,
}
}
@ -261,10 +268,26 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
intercrate: false,
intercrate_ambiguity_causes: None,
allow_negative_impls: false,
const_impls_required: false,
query_mode,
}
}
pub fn with_constness(
infcx: &'cx InferCtxt<'cx, 'tcx>,
constness: hir::Constness,
) -> SelectionContext<'cx, 'tcx> {
SelectionContext {
infcx,
freshener: infcx.freshener_keep_static(),
intercrate: false,
intercrate_ambiguity_causes: None,
allow_negative_impls: false,
const_impls_required: matches!(constness, hir::Constness::Const),
query_mode: TraitQueryMode::Standard,
}
}
/// Enables tracking of intercrate ambiguity causes. These are
/// used in coherence to give improved diagnostics. We don't do
/// this until we detect a coherence error because it can lead to
@ -293,6 +316,18 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
self.infcx.tcx
}
/// returns `true` if the predicate is considered `const` to
/// this selection context.
pub fn is_predicate_const(&self, pred: ty::Predicate<'_>) -> bool {
match pred.kind().skip_binder() {
ty::PredicateKind::Trait(ty::TraitPredicate {
constness: hir::Constness::Const,
..
}) if self.const_impls_required => true,
_ => false,
}
}
///////////////////////////////////////////////////////////////////////////
// Selection
//
@ -454,7 +489,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let result = ensure_sufficient_stack(|| {
let bound_predicate = obligation.predicate.kind();
match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(t, _) => {
ty::PredicateKind::Trait(t) => {
let t = bound_predicate.rebind(t);
debug_assert!(!t.has_escaping_bound_vars());
let obligation = obligation.with(t);
@ -762,8 +797,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// if the regions match exactly.
let cycle = stack.iter().skip(1).take_while(|s| s.depth >= cycle_depth);
let tcx = self.tcx();
let cycle =
cycle.map(|stack| stack.obligation.predicate.without_const().to_predicate(tcx));
let cycle = cycle.map(|stack| stack.obligation.predicate.to_predicate(tcx));
if self.coinductive_match(cycle) {
debug!("evaluate_stack --> recursive, coinductive");
Some(EvaluatedToOk)
@ -805,7 +839,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
// terms of `Fn` etc, but we could probably make this more
// precise still.
let unbound_input_types =
stack.fresh_trait_ref.skip_binder().substs.types().any(|ty| ty.is_fresh());
stack.fresh_trait_ref.value.skip_binder().substs.types().any(|ty| ty.is_fresh());
// This check was an imperfect workaround for a bug in the old
// intercrate mode; it should be removed when that goes away.
if unbound_input_types && self.intercrate {
@ -873,7 +907,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
fn coinductive_predicate(&self, predicate: ty::Predicate<'tcx>) -> bool {
let result = match predicate.kind().skip_binder() {
ty::PredicateKind::Trait(ref data, _) => self.tcx().trait_is_auto(data.def_id()),
ty::PredicateKind::Trait(ref data) => self.tcx().trait_is_auto(data.def_id()),
_ => false,
};
debug!(?predicate, ?result, "coinductive_predicate");
@ -926,7 +960,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
fn check_evaluation_cache(
&self,
param_env: ty::ParamEnv<'tcx>,
trait_ref: ty::PolyTraitRef<'tcx>,
trait_ref: ty::ConstnessAnd<ty::PolyTraitRef<'tcx>>,
) -> Option<EvaluationResult> {
let tcx = self.tcx();
if self.can_use_global_caches(param_env) {
@ -940,7 +974,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
fn insert_evaluation_cache(
&mut self,
param_env: ty::ParamEnv<'tcx>,
trait_ref: ty::PolyTraitRef<'tcx>,
trait_ref: ty::ConstnessAnd<ty::PolyTraitRef<'tcx>>,
dep_node: DepNodeIndex,
result: EvaluationResult,
) {
@ -1016,13 +1050,44 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
(result, dep_node)
}
// Treat negative impls as unimplemented, and reservation impls as ambiguity.
fn filter_negative_and_reservation_impls(
#[instrument(level = "debug", skip(self))]
fn filter_impls(
&mut self,
candidate: SelectionCandidate<'tcx>,
obligation: &TraitObligation<'tcx>,
) -> SelectionResult<'tcx, SelectionCandidate<'tcx>> {
let tcx = self.tcx();
// Respect const trait obligations
if self.const_impls_required {
if let hir::Constness::Const = obligation.predicate.skip_binder().constness {
if Some(obligation.predicate.skip_binder().trait_ref.def_id)
!= tcx.lang_items().sized_trait()
// const Sized bounds are skipped
{
match candidate {
// const impl
ImplCandidate(def_id)
if tcx.impl_constness(def_id) == hir::Constness::Const => {}
// const param
ParamCandidate(ty::ConstnessAnd {
constness: hir::Constness::Const,
..
}) => {}
// auto trait impl
AutoImplCandidate(..) => {}
// generator, this will raise error in other places
// or ignore error with const_async_blocks feature
GeneratorCandidate => {}
_ => {
// reject all other types of candidates
return Err(Unimplemented);
}
}
}
}
}
// Treat negative impls as unimplemented, and reservation impls as ambiguity.
if let ImplCandidate(def_id) = candidate {
let tcx = self.tcx();
match tcx.impl_polarity(def_id) {
ty::ImplPolarity::Negative if !self.allow_negative_impls => {
return Err(Unimplemented);
@ -1036,7 +1101,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
let value = attr.and_then(|a| a.value_str());
if let Some(value) = value {
debug!(
"filter_negative_and_reservation_impls: \
"filter_impls: \
reservation impl ambiguity on {:?}",
def_id
);
@ -1103,13 +1168,19 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
cache_fresh_trait_pred: ty::PolyTraitPredicate<'tcx>,
) -> Option<SelectionResult<'tcx, SelectionCandidate<'tcx>>> {
let tcx = self.tcx();
let trait_ref = &cache_fresh_trait_pred.skip_binder().trait_ref;
let pred = &cache_fresh_trait_pred.skip_binder();
let trait_ref = pred.trait_ref;
if self.can_use_global_caches(param_env) {
if let Some(res) = tcx.selection_cache.get(&param_env.and(*trait_ref), tcx) {
if let Some(res) = tcx
.selection_cache
.get(&param_env.and(trait_ref).with_constness(pred.constness), tcx)
{
return Some(res);
}
}
self.infcx.selection_cache.get(&param_env.and(*trait_ref), tcx)
self.infcx
.selection_cache
.get(&param_env.and(trait_ref).with_constness(pred.constness), tcx)
}
/// Determines whether can we safely cache the result
@ -1146,7 +1217,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
candidate: SelectionResult<'tcx, SelectionCandidate<'tcx>>,
) {
let tcx = self.tcx();
let trait_ref = cache_fresh_trait_pred.skip_binder().trait_ref;
let pred = cache_fresh_trait_pred.skip_binder();
let trait_ref = pred.trait_ref;
if !self.can_cache_candidate(&candidate) {
debug!(?trait_ref, ?candidate, "insert_candidate_cache - candidate is not cacheable");
@ -1160,14 +1232,22 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
if !candidate.needs_infer() {
debug!(?trait_ref, ?candidate, "insert_candidate_cache global");
// This may overwrite the cache with the same value.
tcx.selection_cache.insert(param_env.and(trait_ref), dep_node, candidate);
tcx.selection_cache.insert(
param_env.and(trait_ref).with_constness(pred.constness),
dep_node,
candidate,
);
return;
}
}
}
debug!(?trait_ref, ?candidate, "insert_candidate_cache local");
self.infcx.selection_cache.insert(param_env.and(trait_ref), dep_node, candidate);
self.infcx.selection_cache.insert(
param_env.and(trait_ref).with_constness(pred.constness),
dep_node,
candidate,
);
}
/// Matches a predicate against the bounds of its self type.
@ -1213,7 +1293,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
.enumerate()
.filter_map(|(idx, bound)| {
let bound_predicate = bound.kind();
if let ty::PredicateKind::Trait(pred, _) = bound_predicate.skip_binder() {
if let ty::PredicateKind::Trait(pred) = bound_predicate.skip_binder() {
let bound = bound_predicate.rebind(pred.trait_ref);
if self.infcx.probe(|_| {
match self.match_normalize_trait_ref(
@ -1997,8 +2077,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
fn match_fresh_trait_refs(
&self,
previous: ty::PolyTraitRef<'tcx>,
current: ty::PolyTraitRef<'tcx>,
previous: ty::ConstnessAnd<ty::PolyTraitRef<'tcx>>,
current: ty::ConstnessAnd<ty::PolyTraitRef<'tcx>>,
param_env: ty::ParamEnv<'tcx>,
) -> bool {
let mut matcher = ty::_match::Match::new(self.tcx(), param_env);
@ -2010,8 +2090,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
previous_stack: TraitObligationStackList<'o, 'tcx>,
obligation: &'o TraitObligation<'tcx>,
) -> TraitObligationStack<'o, 'tcx> {
let fresh_trait_ref =
obligation.predicate.to_poly_trait_ref().fold_with(&mut self.freshener);
let fresh_trait_ref = obligation
.predicate
.to_poly_trait_ref()
.fold_with(&mut self.freshener)
.with_constness(obligation.predicate.skip_binder().constness);
let dfn = previous_stack.cache.next_dfn();
let depth = previous_stack.depth() + 1;
@ -2290,7 +2373,7 @@ struct ProvisionalEvaluationCache<'tcx> {
/// - then we determine that `E` is in error -- we will then clear
/// all cache values whose DFN is >= 4 -- in this case, that
/// means the cached value for `F`.
map: RefCell<FxHashMap<ty::PolyTraitRef<'tcx>, ProvisionalEvaluation>>,
map: RefCell<FxHashMap<ty::ConstnessAnd<ty::PolyTraitRef<'tcx>>, ProvisionalEvaluation>>,
}
/// A cache value for the provisional cache: contains the depth-first
@ -2322,7 +2405,7 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> {
/// `reached_depth` (from the returned value).
fn get_provisional(
&self,
fresh_trait_ref: ty::PolyTraitRef<'tcx>,
fresh_trait_ref: ty::ConstnessAnd<ty::PolyTraitRef<'tcx>>,
) -> Option<ProvisionalEvaluation> {
debug!(
?fresh_trait_ref,
@ -2340,7 +2423,7 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> {
&self,
from_dfn: usize,
reached_depth: usize,
fresh_trait_ref: ty::PolyTraitRef<'tcx>,
fresh_trait_ref: ty::ConstnessAnd<ty::PolyTraitRef<'tcx>>,
result: EvaluationResult,
) {
debug!(?from_dfn, ?fresh_trait_ref, ?result, "insert_provisional");
@ -2418,7 +2501,7 @@ impl<'tcx> ProvisionalEvaluationCache<'tcx> {
fn on_completion(
&self,
dfn: usize,
mut op: impl FnMut(ty::PolyTraitRef<'tcx>, EvaluationResult),
mut op: impl FnMut(ty::ConstnessAnd<ty::PolyTraitRef<'tcx>>, EvaluationResult),
) {
debug!(?dfn, "on_completion");

4
compiler/rustc_trait_selection/src/traits/wf.rs
View File

@ -108,7 +108,7 @@ pub fn predicate_obligations<'a, 'tcx>(
// It's ok to skip the binder here because wf code is prepared for it
match predicate.kind().skip_binder() {
ty::PredicateKind::Trait(t, _) => {
ty::PredicateKind::Trait(t) => {
wf.compute_trait_ref(&t.trait_ref, Elaborate::None);
}
ty::PredicateKind::RegionOutlives(..) => {}
@ -226,7 +226,7 @@ fn extend_cause_with_original_assoc_item_obligation<'tcx>(
}
}
}
ty::PredicateKind::Trait(pred, _) => {
ty::PredicateKind::Trait(pred) => {
// An associated item obligation born out of the `trait` failed to be met. An example
// can be seen in `ui/associated-types/point-at-type-on-obligation-failure-2.rs`.
debug!("extended_cause_with_original_assoc_item_obligation trait proj {:?}", pred);

8
compiler/rustc_traits/src/chalk/lowering.rs
View File

@ -87,7 +87,7 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::InEnvironment<chalk_ir::Goal<RustInterner<'
ty::PredicateKind::TypeWellFormedFromEnv(ty) => {
chalk_ir::DomainGoal::FromEnv(chalk_ir::FromEnv::Ty(ty.lower_into(interner)))
}
ty::PredicateKind::Trait(predicate, _) => chalk_ir::DomainGoal::FromEnv(
ty::PredicateKind::Trait(predicate) => chalk_ir::DomainGoal::FromEnv(
chalk_ir::FromEnv::Trait(predicate.trait_ref.lower_into(interner)),
),
ty::PredicateKind::RegionOutlives(predicate) => chalk_ir::DomainGoal::Holds(
@ -137,7 +137,7 @@ impl<'tcx> LowerInto<'tcx, chalk_ir::GoalData<RustInterner<'tcx>>> for ty::Predi
collect_bound_vars(interner, interner.tcx, self.kind());
let value = match predicate {
ty::PredicateKind::Trait(predicate, _) => {
ty::PredicateKind::Trait(predicate) => {
chalk_ir::GoalData::DomainGoal(chalk_ir::DomainGoal::Holds(
chalk_ir::WhereClause::Implemented(predicate.trait_ref.lower_into(interner)),
))
@ -569,7 +569,7 @@ impl<'tcx> LowerInto<'tcx, Option<chalk_ir::QuantifiedWhereClause<RustInterner<'
let (predicate, binders, _named_regions) =
collect_bound_vars(interner, interner.tcx, self.kind());
let value = match predicate {
ty::PredicateKind::Trait(predicate, _) => {
ty::PredicateKind::Trait(predicate) => {
Some(chalk_ir::WhereClause::Implemented(predicate.trait_ref.lower_into(interner)))
}
ty::PredicateKind::RegionOutlives(predicate) => {
@ -702,7 +702,7 @@ impl<'tcx> LowerInto<'tcx, Option<chalk_solve::rust_ir::QuantifiedInlineBound<Ru
let (predicate, binders, _named_regions) =
collect_bound_vars(interner, interner.tcx, self.kind());
match predicate {
ty::PredicateKind::Trait(predicate, _) => Some(chalk_ir::Binders::new(
ty::PredicateKind::Trait(predicate) => Some(chalk_ir::Binders::new(
binders,
chalk_solve::rust_ir::InlineBound::TraitBound(
predicate.trait_ref.lower_into(interner),

16
compiler/rustc_traits/src/type_op.rs
View File

@ -6,7 +6,9 @@ use rustc_infer::infer::{InferCtxt, TyCtxtInferExt};
use rustc_infer::traits::TraitEngineExt as _;
use rustc_middle::ty::query::Providers;
use rustc_middle::ty::subst::{GenericArg, Subst, UserSelfTy, UserSubsts};
use rustc_middle::ty::{self, FnSig, Lift, PolyFnSig, Ty, TyCtxt, TypeFoldable, Variance};
use rustc_middle::ty::{
self, FnSig, Lift, PolyFnSig, PredicateKind, Ty, TyCtxt, TypeFoldable, Variance,
};
use rustc_middle::ty::{ParamEnv, ParamEnvAnd, Predicate, ToPredicate};
use rustc_span::DUMMY_SP;
use rustc_trait_selection::infer::InferCtxtBuilderExt;
@ -85,7 +87,16 @@ impl AscribeUserTypeCx<'me, 'tcx> {
Ok(())
}
fn prove_predicate(&mut self, predicate: Predicate<'tcx>) {
fn prove_predicate(&mut self, mut predicate: Predicate<'tcx>) {
if let PredicateKind::Trait(mut tr) = predicate.kind().skip_binder() {
if let hir::Constness::Const = tr.constness {
// FIXME check if we actually want to prove const predicates inside AscribeUserType
tr.constness = hir::Constness::NotConst;
predicate =
predicate.kind().rebind(PredicateKind::Trait(tr)).to_predicate(self.tcx());
}
}
self.fulfill_cx.register_predicate_obligation(
self.infcx,
Obligation::new(ObligationCause::dummy(), self.param_env, predicate),
@ -126,6 +137,7 @@ impl AscribeUserTypeCx<'me, 'tcx> {
// outlives" error messages.
let instantiated_predicates =
self.tcx().predicates_of(def_id).instantiate(self.tcx(), substs);
debug!(?instantiated_predicates.predicates);
for instantiated_predicate in instantiated_predicates.predicates {
let instantiated_predicate = self.normalize(instantiated_predicate);
self.prove_predicate(instantiated_predicate);

2
compiler/rustc_typeck/src/astconv/mod.rs
View File

@ -1340,7 +1340,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
let bound_predicate = obligation.predicate.kind();
match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(pred, _) => {
ty::PredicateKind::Trait(pred) => {
let pred = bound_predicate.rebind(pred);
associated_types.entry(span).or_default().extend(
tcx.associated_items(pred.def_id())

16
compiler/rustc_typeck/src/check/_match.rs
View File

@ -606,16 +606,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let mut suggest_box = !obligations.is_empty();
for o in obligations {
match o.predicate.kind().skip_binder() {
ty::PredicateKind::Trait(t, constness) => {
let pred = ty::PredicateKind::Trait(
ty::TraitPredicate {
trait_ref: ty::TraitRef {
def_id: t.def_id(),
substs: self.infcx.tcx.mk_substs_trait(outer_ty, &[]),
},
ty::PredicateKind::Trait(t) => {
let pred = ty::PredicateKind::Trait(ty::TraitPredicate {
trait_ref: ty::TraitRef {
def_id: t.def_id(),
substs: self.infcx.tcx.mk_substs_trait(outer_ty, &[]),
},
constness,
);
constness: t.constness,
});
let obl = Obligation::new(
o.cause.clone(),
self.param_env,

4
compiler/rustc_typeck/src/check/coercion.rs
View File

@ -587,9 +587,7 @@ impl<'f, 'tcx> Coerce<'f, 'tcx> {
debug!("coerce_unsized resolve step: {:?}", obligation);
let bound_predicate = obligation.predicate.kind();
let trait_pred = match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(trait_pred, _)
if traits.contains(&trait_pred.def_id()) =>
{
ty::PredicateKind::Trait(trait_pred) if traits.contains(&trait_pred.def_id()) => {
if unsize_did == trait_pred.def_id() {
let self_ty = trait_pred.self_ty();
let unsize_ty = trait_pred.trait_ref.substs[1].expect_ty();

12
compiler/rustc_typeck/src/check/compare_method.rs
View File

@ -1292,7 +1292,13 @@ pub fn check_type_bounds<'tcx>(
};
tcx.infer_ctxt().enter(move |infcx| {
let inh = Inherited::new(infcx, impl_ty.def_id.expect_local());
let constness = impl_ty
.container
.impl_def_id()
.map(|did| tcx.impl_constness(did))
.unwrap_or(hir::Constness::NotConst);
let inh = Inherited::with_constness(infcx, impl_ty.def_id.expect_local(), constness);
let infcx = &inh.infcx;
let mut selcx = traits::SelectionContext::new(&infcx);
@ -1334,7 +1340,9 @@ pub fn check_type_bounds<'tcx>(
// Check that all obligations are satisfied by the implementation's
// version.
if let Err(ref errors) = inh.fulfillment_cx.borrow_mut().select_all_or_error(&infcx) {
if let Err(ref errors) =
inh.fulfillment_cx.borrow_mut().select_all_with_constness_or_error(&infcx, constness)
{
infcx.report_fulfillment_errors(errors, None, false);
return Err(ErrorReported);
}

2
compiler/rustc_typeck/src/check/dropck.rs
View File

@ -229,7 +229,7 @@ fn ensure_drop_predicates_are_implied_by_item_defn<'tcx>(
let predicate = predicate.kind();
let p = p.kind();
match (predicate.skip_binder(), p.skip_binder()) {
(ty::PredicateKind::Trait(a, _), ty::PredicateKind::Trait(b, _)) => {
(ty::PredicateKind::Trait(a), ty::PredicateKind::Trait(b)) => {
relator.relate(predicate.rebind(a), p.rebind(b)).is_ok()
}
(ty::PredicateKind::Projection(a), ty::PredicateKind::Projection(b)) => {

13
compiler/rustc_typeck/src/check/fn_ctxt/_impl.rs
View File

@ -714,7 +714,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
pub(in super::super) fn select_all_obligations_or_error(&self) {
debug!("select_all_obligations_or_error");
if let Err(errors) = self.fulfillment_cx.borrow_mut().select_all_or_error(&self) {
if let Err(errors) = self
.fulfillment_cx
.borrow_mut()
.select_all_with_constness_or_error(&self, self.inh.constness)
{
self.report_fulfillment_errors(&errors, self.inh.body_id, false);
}
}
@ -725,7 +729,10 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
fallback_has_occurred: bool,
mutate_fulfillment_errors: impl Fn(&mut Vec<traits::FulfillmentError<'tcx>>),
) {
let result = self.fulfillment_cx.borrow_mut().select_where_possible(self);
let result = self
.fulfillment_cx
.borrow_mut()
.select_with_constness_where_possible(self, self.inh.constness);
if let Err(mut errors) = result {
mutate_fulfillment_errors(&mut errors);
self.report_fulfillment_errors(&errors, self.inh.body_id, fallback_has_occurred);
@ -796,7 +803,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
bound_predicate.rebind(data).required_poly_trait_ref(self.tcx),
obligation,
)),
ty::PredicateKind::Trait(data, _) => {
ty::PredicateKind::Trait(data) => {
Some((bound_predicate.rebind(data).to_poly_trait_ref(), obligation))
}
ty::PredicateKind::Subtype(..) => None,

4
compiler/rustc_typeck/src/check/fn_ctxt/checks.rs
View File

@ -923,7 +923,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
continue;
}
if let ty::PredicateKind::Trait(predicate, _) =
if let ty::PredicateKind::Trait(predicate) =
error.obligation.predicate.kind().skip_binder()
{
// Collect the argument position for all arguments that could have caused this
@ -974,7 +974,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
if let hir::ExprKind::Path(qpath) = &path.kind {
if let hir::QPath::Resolved(_, path) = &qpath {
for error in errors {
if let ty::PredicateKind::Trait(predicate, _) =
if let ty::PredicateKind::Trait(predicate) =
error.obligation.predicate.kind().skip_binder()
{
// If any of the type arguments in this path segment caused the

4
compiler/rustc_typeck/src/check/fn_ctxt/mod.rs
View File

@ -174,7 +174,7 @@ impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
}
fn default_constness_for_trait_bounds(&self) -> hir::Constness {
self.tcx.hir().get(self.body_id).constness()
self.tcx.hir().get(self.body_id).constness_for_typeck()
}
fn get_type_parameter_bounds(
@ -194,7 +194,7 @@ impl<'a, 'tcx> AstConv<'tcx> for FnCtxt<'a, 'tcx> {
predicates: tcx.arena.alloc_from_iter(
self.param_env.caller_bounds().iter().filter_map(|predicate| {
match predicate.kind().skip_binder() {
ty::PredicateKind::Trait(data, _) if data.self_ty().is_param(index) => {
ty::PredicateKind::Trait(data) if data.self_ty().is_param(index) => {
// HACK(eddyb) should get the original `Span`.
let span = tcx.def_span(def_id);
Some((predicate, span))

14
compiler/rustc_typeck/src/check/inherited.rs
View File

@ -52,6 +52,9 @@ pub struct Inherited<'a, 'tcx> {
pub(super) deferred_generator_interiors:
RefCell<Vec<(hir::BodyId, Ty<'tcx>, hir::GeneratorKind)>>,
/// Reports whether this is in a const context.
pub(super) constness: hir::Constness,
pub(super) body_id: Option<hir::BodyId>,
}
@ -93,6 +96,16 @@ impl<'tcx> InheritedBuilder<'tcx> {
impl Inherited<'a, 'tcx> {
pub(super) fn new(infcx: InferCtxt<'a, 'tcx>, def_id: LocalDefId) -> Self {
let tcx = infcx.tcx;
let item_id = tcx.hir().local_def_id_to_hir_id(def_id);
Self::with_constness(infcx, def_id, tcx.hir().get(item_id).constness_for_typeck())
}
pub(super) fn with_constness(
infcx: InferCtxt<'a, 'tcx>,
def_id: LocalDefId,
constness: hir::Constness,
) -> Self {
let tcx = infcx.tcx;
let item_id = tcx.hir().local_def_id_to_hir_id(def_id);
let body_id = tcx.hir().maybe_body_owned_by(item_id);
@ -108,6 +121,7 @@ impl Inherited<'a, 'tcx> {
deferred_call_resolutions: RefCell::new(Default::default()),
deferred_cast_checks: RefCell::new(Vec::new()),
deferred_generator_interiors: RefCell::new(Vec::new()),
constness,
body_id,
}
}

2
compiler/rustc_typeck/src/check/method/confirm.rs
View File

@ -507,7 +507,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
traits::elaborate_predicates(self.tcx, predicates.predicates.iter().copied())
// We don't care about regions here.
.filter_map(|obligation| match obligation.predicate.kind().skip_binder() {
ty::PredicateKind::Trait(trait_pred, _) if trait_pred.def_id() == sized_def_id => {
ty::PredicateKind::Trait(trait_pred) if trait_pred.def_id() == sized_def_id => {
let span = iter::zip(&predicates.predicates, &predicates.spans)
.find_map(
|(p, span)| {

2
compiler/rustc_typeck/src/check/method/probe.rs
View File

@ -832,7 +832,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
let bounds = self.param_env.caller_bounds().iter().filter_map(|predicate| {
let bound_predicate = predicate.kind();
match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(trait_predicate, _) => {
ty::PredicateKind::Trait(trait_predicate) => {
match *trait_predicate.trait_ref.self_ty().kind() {
ty::Param(p) if p == param_ty => {
Some(bound_predicate.rebind(trait_predicate.trait_ref))

6
compiler/rustc_typeck/src/check/method/suggest.rs
View File

@ -683,7 +683,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let mut collect_type_param_suggestions =
|self_ty: Ty<'tcx>, parent_pred: &ty::Predicate<'tcx>, obligation: &str| {
// We don't care about regions here, so it's fine to skip the binder here.
if let (ty::Param(_), ty::PredicateKind::Trait(p, _)) =
if let (ty::Param(_), ty::PredicateKind::Trait(p)) =
(self_ty.kind(), parent_pred.kind().skip_binder())
{
if let ty::Adt(def, _) = p.trait_ref.self_ty().kind() {
@ -763,7 +763,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
bound_span_label(projection_ty.self_ty(), &obligation, &quiet);
Some((obligation, projection_ty.self_ty()))
}
ty::PredicateKind::Trait(poly_trait_ref, _) => {
ty::PredicateKind::Trait(poly_trait_ref) => {
let p = poly_trait_ref.trait_ref;
let self_ty = p.self_ty();
let path = p.print_only_trait_path();
@ -1200,7 +1200,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
match p.kind().skip_binder() {
// Hide traits if they are present in predicates as they can be fixed without
// having to implement them.
ty::PredicateKind::Trait(t, _) => t.def_id() == info.def_id,
ty::PredicateKind::Trait(t) => t.def_id() == info.def_id,
ty::PredicateKind::Projection(p) => {
p.projection_ty.item_def_id == info.def_id
}

2
compiler/rustc_typeck/src/check/mod.rs
View File

@ -689,7 +689,7 @@ fn bounds_from_generic_predicates<'tcx>(
debug!("predicate {:?}", predicate);
let bound_predicate = predicate.kind();
match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(trait_predicate, _) => {
ty::PredicateKind::Trait(trait_predicate) => {
let entry = types.entry(trait_predicate.self_ty()).or_default();
let def_id = trait_predicate.def_id();
if Some(def_id) != tcx.lang_items().sized_trait() {

8
compiler/rustc_typeck/src/collect.rs
View File

@ -364,7 +364,7 @@ impl AstConv<'tcx> for ItemCtxt<'tcx> {
}
fn default_constness_for_trait_bounds(&self) -> hir::Constness {
self.node().constness()
self.node().constness_for_typeck()
}
fn get_type_parameter_bounds(
@ -640,7 +640,7 @@ fn type_param_predicates(
)
.into_iter()
.filter(|(predicate, _)| match predicate.kind().skip_binder() {
ty::PredicateKind::Trait(data, _) => data.self_ty().is_param(index),
ty::PredicateKind::Trait(data) => data.self_ty().is_param(index),
_ => false,
}),
);
@ -1198,7 +1198,7 @@ fn super_predicates_that_define_assoc_type(
// which will, in turn, reach indirect supertraits.
for &(pred, span) in superbounds {
debug!("superbound: {:?}", pred);
if let ty::PredicateKind::Trait(bound, _) = pred.kind().skip_binder() {
if let ty::PredicateKind::Trait(bound) = pred.kind().skip_binder() {
tcx.at(span).super_predicates_of(bound.def_id());
}
}
@ -2439,7 +2439,7 @@ fn explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericPredicat
.iter()
.copied()
.filter(|(pred, _)| match pred.kind().skip_binder() {
ty::PredicateKind::Trait(tr, _) => !is_assoc_item_ty(tr.self_ty()),
ty::PredicateKind::Trait(tr) => !is_assoc_item_ty(tr.self_ty()),
ty::PredicateKind::Projection(proj) => {
!is_assoc_item_ty(proj.projection_ty.self_ty())
}

2
compiler/rustc_typeck/src/collect/item_bounds.rs
View File

@ -38,7 +38,7 @@ fn associated_type_bounds<'tcx>(
let bounds_from_parent = trait_predicates.predicates.iter().copied().filter(|(pred, _)| {
match pred.kind().skip_binder() {
ty::PredicateKind::Trait(tr, _) => tr.self_ty() == item_ty,
ty::PredicateKind::Trait(tr) => tr.self_ty() == item_ty,
ty::PredicateKind::Projection(proj) => proj.projection_ty.self_ty() == item_ty,
ty::PredicateKind::TypeOutlives(outlives) => outlives.0 == item_ty,
_ => false,

16
compiler/rustc_typeck/src/impl_wf_check/min_specialization.rs
View File

@ -366,7 +366,10 @@ fn check_specialization_on<'tcx>(tcx: TyCtxt<'tcx>, predicate: ty::Predicate<'tc
_ if predicate.is_global() => (),
// We allow specializing on explicitly marked traits with no associated
// items.
ty::PredicateKind::Trait(pred, hir::Constness::NotConst) => {
ty::PredicateKind::Trait(ty::TraitPredicate {
trait_ref,
constness: hir::Constness::NotConst,
}) => {
if !matches!(
trait_predicate_kind(tcx, predicate),
Some(TraitSpecializationKind::Marker)
@ -376,7 +379,7 @@ fn check_specialization_on<'tcx>(tcx: TyCtxt<'tcx>, predicate: ty::Predicate<'tc
span,
&format!(
"cannot specialize on trait `{}`",
tcx.def_path_str(pred.def_id()),
tcx.def_path_str(trait_ref.def_id),
),
)
.emit()
@ -394,10 +397,11 @@ fn trait_predicate_kind<'tcx>(
predicate: ty::Predicate<'tcx>,
) -> Option<TraitSpecializationKind> {
match predicate.kind().skip_binder() {
ty::PredicateKind::Trait(pred, hir::Constness::NotConst) => {
Some(tcx.trait_def(pred.def_id()).specialization_kind)
}
ty::PredicateKind::Trait(_, hir::Constness::Const)
ty::PredicateKind::Trait(ty::TraitPredicate {
trait_ref,
constness: hir::Constness::NotConst,
}) => Some(tcx.trait_def(trait_ref.def_id).specialization_kind),
ty::PredicateKind::Trait(_)
| ty::PredicateKind::RegionOutlives(_)
| ty::PredicateKind::TypeOutlives(_)
| ty::PredicateKind::Projection(_)

7
library/alloc/src/collections/btree/map/tests.rs
View File

@ -1786,13 +1786,6 @@ fn test_ord_absence() {
}
}
#[allow(dead_code)]
fn test_const() {
const MAP: &'static BTreeMap<(), ()> = &BTreeMap::new();
const LEN: usize = MAP.len();
const IS_EMPTY: bool = MAP.is_empty();
}
#[test]
fn test_occupied_entry_key() {
let mut a = BTreeMap::new();

7
library/alloc/src/collections/btree/set/tests.rs
View File

@ -16,13 +16,6 @@ fn test_clone_eq() {
assert_eq!(m.clone(), m);
}
#[allow(dead_code)]
fn test_const() {
const SET: &'static BTreeSet<()> = &BTreeSet::new();
const LEN: usize = SET.len();
const IS_EMPTY: bool = SET.is_empty();
}
#[test]
fn test_iter_min_max() {
let mut a = BTreeSet::new();

53
library/alloc/tests/const_fns.rs Normal file
View File

@ -0,0 +1,53 @@
// Test several functions can be used for constants
// 1. Vec::new()
// 2. String::new()
// 3. BTreeMap::new()
// 4. BTreeSet::new()
#[allow(dead_code)]
pub const MY_VEC: Vec<usize> = Vec::new();
#[allow(dead_code)]
pub const MY_STRING: String = String::new();
// FIXME remove this struct once we put `K: ?const Ord` on BTreeMap::new.
#[derive(PartialEq, Eq, PartialOrd)]
pub struct MyType;
impl const Ord for MyType {
fn cmp(&self, _: &Self) -> Ordering {
Ordering::Equal
}
fn max(self, _: Self) -> Self {
Self
}
fn min(self, _: Self) -> Self {
Self
}
fn clamp(self, _: Self, _: Self) -> Self {
Self
}
}
use core::cmp::Ordering;
use std::collections::{BTreeMap, BTreeSet};
pub const MY_BTREEMAP: BTreeMap<MyType, MyType> = BTreeMap::new();
pub const MAP: &'static BTreeMap<MyType, MyType> = &MY_BTREEMAP;
pub const MAP_LEN: usize = MAP.len();
pub const MAP_IS_EMPTY: bool = MAP.is_empty();
pub const MY_BTREESET: BTreeSet<MyType> = BTreeSet::new();
pub const SET: &'static BTreeSet<MyType> = &MY_BTREESET;
pub const SET_LEN: usize = SET.len();
pub const SET_IS_EMPTY: bool = SET.is_empty();
#[test]
fn test_const() {
assert_eq!(MAP_LEN, 0);
assert_eq!(SET_LEN, 0);
assert!(MAP_IS_EMPTY && SET_IS_EMPTY)
}

5
library/alloc/tests/lib.rs
View File

@ -23,6 +23,10 @@
#![feature(slice_partition_dedup)]
#![feature(vec_spare_capacity)]
#![feature(string_remove_matches)]
#![feature(const_btree_new)]
#![feature(const_trait_impl)]
// FIXME remove this when const_trait_impl is not incomplete anymore
#![allow(incomplete_features)]
use std::collections::hash_map::DefaultHasher;
use std::hash::{Hash, Hasher};
@ -32,6 +36,7 @@ mod binary_heap;
mod borrow;
mod boxed;
mod btree_set_hash;
mod const_fns;
mod cow_str;
mod fmt;
mod heap;

4
src/librustdoc/clean/auto_trait.rs
View File

@ -316,7 +316,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
let bound_predicate = pred.kind();
let tcx = self.cx.tcx;
let regions = match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(poly_trait_pred, _) => {
ty::PredicateKind::Trait(poly_trait_pred) => {
tcx.collect_referenced_late_bound_regions(&bound_predicate.rebind(poly_trait_pred))
}
ty::PredicateKind::Projection(poly_proj_pred) => {
@ -463,7 +463,7 @@ impl<'a, 'tcx> AutoTraitFinder<'a, 'tcx> {
.filter(|p| {
!orig_bounds.contains(p)
|| match p.kind().skip_binder() {
ty::PredicateKind::Trait(pred, _) => pred.def_id() == sized_trait,
ty::PredicateKind::Trait(pred) => pred.def_id() == sized_trait,
_ => false,
}
})

8
src/librustdoc/clean/mod.rs
View File

@ -325,7 +325,7 @@ impl<'a> Clean<Option<WherePredicate>> for ty::Predicate<'a> {
fn clean(&self, cx: &mut DocContext<'_>) -> Option<WherePredicate> {
let bound_predicate = self.kind();
match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(pred, _) => Some(bound_predicate.rebind(pred).clean(cx)),
ty::PredicateKind::Trait(pred) => Some(bound_predicate.rebind(pred).clean(cx)),
ty::PredicateKind::RegionOutlives(pred) => pred.clean(cx),
ty::PredicateKind::TypeOutlives(pred) => pred.clean(cx),
ty::PredicateKind::Projection(pred) => Some(pred.clean(cx)),
@ -637,7 +637,7 @@ impl<'a, 'tcx> Clean<Generics> for (&'a ty::Generics, ty::GenericPredicates<'tcx
let param_idx = (|| {
let bound_p = p.kind();
match bound_p.skip_binder() {
ty::PredicateKind::Trait(pred, _constness) => {
ty::PredicateKind::Trait(pred) => {
if let ty::Param(param) = pred.self_ty().kind() {
return Some(param.index);
}
@ -1555,9 +1555,7 @@ impl<'tcx> Clean<Type> for Ty<'tcx> {
.filter_map(|bound| {
let bound_predicate = bound.kind();
let trait_ref = match bound_predicate.skip_binder() {
ty::PredicateKind::Trait(tr, _constness) => {
bound_predicate.rebind(tr.trait_ref)
}
ty::PredicateKind::Trait(tr) => bound_predicate.rebind(tr.trait_ref),
ty::PredicateKind::TypeOutlives(ty::OutlivesPredicate(_ty, reg)) => {
if let Some(r) = reg.clean(cx) {
regions.push(GenericBound::Outlives(r));

2
src/librustdoc/clean/simplify.rs
View File

@ -139,7 +139,7 @@ fn trait_is_same_or_supertrait(cx: &DocContext<'_>, child: DefId, trait_: DefId)
.predicates
.iter()
.filter_map(|(pred, _)| {
if let ty::PredicateKind::Trait(pred, _) = pred.kind().skip_binder() {
if let ty::PredicateKind::Trait(pred) = pred.kind().skip_binder() {
if pred.trait_ref.self_ty() == self_ty { Some(pred.def_id()) } else { None }
} else {
None

20
src/test/ui/collections-const-new.rs
View File

@ -1,20 +0,0 @@
// check-pass
// Test several functions can be used for constants
// 1. Vec::new()
// 2. String::new()
// 3. BTreeMap::new()
// 4. BTreeSet::new()
#![feature(const_btree_new)]
const MY_VEC: Vec<usize> = Vec::new();
const MY_STRING: String = String::new();
use std::collections::{BTreeMap, BTreeSet};
const MY_BTREEMAP: BTreeMap<u32, u32> = BTreeMap::new();
const MY_BTREESET: BTreeSet<u32> = BTreeSet::new();
fn main() {}

4
src/test/ui/consts/const-eval/issue-49296.rs
View File

@ -1,8 +1,10 @@
// issue-49296: Unsafe shenigans in constants can result in missing errors
#![feature(const_fn_trait_bound)]
#![feature(const_trait_bound_opt_out)]
#![allow(incomplete_features)]
const unsafe fn transmute<T: Copy, U: Copy>(t: T) -> U {
const unsafe fn transmute<T: ?const Copy, U: ?const Copy>(t: T) -> U {
#[repr(C)]
union Transmute<T: Copy, U: Copy> {
from: T,

2
src/test/ui/consts/const-eval/issue-49296.stderr
View File

@ -1,5 +1,5 @@
error[E0080]: evaluation of constant value failed
--> $DIR/issue-49296.rs:18:16
--> $DIR/issue-49296.rs:20:16
|
LL | const X: u64 = *wat(42);
| ^^^^^^^^ pointer to alloc2 was dereferenced after this allocation got freed

4
src/test/ui/generic-associated-types/projection-bound-cycle-generic.stderr
View File

@ -1,8 +1,8 @@
error[E0275]: overflow evaluating the requirement `<T as Foo>::Item: Sized`
--> $DIR/projection-bound-cycle-generic.rs:44:18
|
LL | struct OnlySized<T> where T: Sized { f: T }
| - required by this bound in `OnlySized`
LL | type Item: Sized where <Self as Foo>::Item: Sized;
| ----- required by this bound in `Foo::Item`
...
LL | type Assoc = OnlySized<<T as Foo>::Item>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^

4
src/test/ui/generic-associated-types/projection-bound-cycle.stderr
View File

@ -1,8 +1,8 @@
error[E0275]: overflow evaluating the requirement `<T as Foo>::Item: Sized`
--> $DIR/projection-bound-cycle.rs:46:18
|
LL | struct OnlySized<T> where T: Sized { f: T }
| - required by this bound in `OnlySized`
LL | type Item: Sized where <Self as Foo>::Item: Sized;
| ----- required by this bound in `Foo::Item`
...
LL | type Assoc = OnlySized<<T as Foo>::Item>;
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^

17
src/test/ui/rfc-2632-const-trait-impl/assoc-type.rs
View File

@ -1,9 +1,7 @@
// ignore-test
// FIXME: This test should fail since, within a const impl of `Foo`, the bound on `Foo::Bar` should
// require a const impl of `Add` for the associated type.
// FIXME(fee1-dead): this should have a better error message
#![feature(const_trait_impl)]
#![feature(const_trait_bound_opt_out)]
#![allow(incomplete_features)]
struct NonConstAdd(i32);
@ -21,6 +19,15 @@ trait Foo {
impl const Foo for NonConstAdd {
type Bar = NonConstAdd;
//~^ ERROR
}
trait Baz {
type Qux: ?const std::ops::Add;
}
impl const Baz for NonConstAdd {
type Qux = NonConstAdd; // OK
}
fn main() {}

18
src/test/ui/rfc-2632-const-trait-impl/assoc-type.stderr Normal file
View File

@ -0,0 +1,18 @@
error[E0277]: cannot add `NonConstAdd` to `NonConstAdd`
--> $DIR/assoc-type.rs:21:5
|
LL | type Bar: std::ops::Add;
| ------------- required by this bound in `Foo::Bar`
...
LL | type Bar = NonConstAdd;
| ^^^^^^^^^^^^^^^^^^^^^^^ no implementation for `NonConstAdd + NonConstAdd`
|
= help: the trait `Add` is not implemented for `NonConstAdd`
help: consider introducing a `where` bound, but there might be an alternative better way to express this requirement
|
LL | impl const Foo for NonConstAdd where NonConstAdd: Add {
| ++++++++++++++++++++++
error: aborting due to previous error
For more information about this error, try `rustc --explain E0277`.

4
src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.rs
View File

@ -1,7 +1,5 @@
// FIXME(jschievink): this is not rejected correctly (only when the non-const impl is actually used)
// ignore-test
#![feature(const_trait_impl)]
#![feature(const_fn_trait_bound)]
struct S;

14
src/test/ui/rfc-2632-const-trait-impl/call-generic-method-nonconst.stderr Normal file
View File

@ -0,0 +1,14 @@
error[E0277]: can't compare `S` with `S`
--> $DIR/call-generic-method-nonconst.rs:19:34
|
LL | const fn equals_self<T: PartialEq>(t: &T) -> bool {
| --------- required by this bound in `equals_self`
...
LL | pub const EQ: bool = equals_self(&S);
| ^^ no implementation for `S == S`
|
= help: the trait `PartialEq` is not implemented for `S`
error: aborting due to previous error
For more information about this error, try `rustc --explain E0277`.

2
src/tools/clippy/clippy_lints/src/future_not_send.rs
View File

@ -93,7 +93,7 @@ impl<'tcx> LateLintPass<'tcx> for FutureNotSend {
cx.tcx.infer_ctxt().enter(|infcx| {
for FulfillmentError { obligation, .. } in send_errors {
infcx.maybe_note_obligation_cause_for_async_await(db, &obligation);
if let Trait(trait_pred, _) = obligation.predicate.kind().skip_binder() {
if let Trait(trait_pred) = obligation.predicate.kind().skip_binder() {
db.note(&format!(
"`{}` doesn't implement `{}`",
trait_pred.self_ty(),

2
src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
View File

@ -121,7 +121,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByValue {
.filter_map(|obligation| {
// Note that we do not want to deal with qualified predicates here.
match obligation.predicate.kind().no_bound_vars() {
Some(ty::PredicateKind::Trait(pred, _)) if pred.def_id() != sized_trait => Some(pred),
Some(ty::PredicateKind::Trait(pred)) if pred.def_id() != sized_trait => Some(pred),
_ => None,
}
})

2
src/tools/clippy/clippy_lints/src/unit_return_expecting_ord.rs
View File

@ -45,7 +45,7 @@ fn get_trait_predicates_for_trait_id<'tcx>(
let mut preds = Vec::new();
for (pred, _) in generics.predicates {
if_chain! {
if let PredicateKind::Trait(poly_trait_pred, _) = pred.kind().skip_binder();
if let PredicateKind::Trait(poly_trait_pred) = pred.kind().skip_binder();
let trait_pred = cx.tcx.erase_late_bound_regions(pred.kind().rebind(poly_trait_pred));
if let Some(trait_def_id) = trait_id;
if trait_def_id == trait_pred.trait_ref.def_id;

2
src/tools/clippy/clippy_utils/src/qualify_min_const_fn.rs
View File

@ -36,7 +36,7 @@ pub fn is_min_const_fn(tcx: TyCtxt<'tcx>, body: &'a Body<'tcx>, msrv: Option<&Ru
ty::PredicateKind::ObjectSafe(_) => panic!("object safe predicate on function: {:#?}", predicate),
ty::PredicateKind::ClosureKind(..) => panic!("closure kind predicate on function: {:#?}", predicate),
ty::PredicateKind::Subtype(_) => panic!("subtype predicate on function: {:#?}", predicate),
ty::PredicateKind::Trait(pred, _) => {
ty::PredicateKind::Trait(pred) => {
if Some(pred.def_id()) == tcx.lang_items().sized_trait() {
continue;
}

2
src/tools/clippy/clippy_utils/src/ty.rs
View File

@ -157,7 +157,7 @@ pub fn is_must_use_ty<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> bool {
ty::Tuple(substs) => substs.types().any(|ty| is_must_use_ty(cx, ty)),
ty::Opaque(ref def_id, _) => {
for (predicate, _) in cx.tcx.explicit_item_bounds(*def_id) {
if let ty::PredicateKind::Trait(trait_predicate, _) = predicate.kind().skip_binder() {
if let ty::PredicateKind::Trait(trait_predicate) = predicate.kind().skip_binder() {
if must_use_attr(cx.tcx.get_attrs(trait_predicate.trait_ref.def_id)).is_some() {
return true;
}