diff options
| -rw-r--r-- | compiler/rustc_infer/src/infer/at.rs | 25 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/hir/mod.rs | 10 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/ty/mod.rs | 7 | ||||
| -rw-r--r-- | compiler/rustc_middle/src/ty/relate.rs | 26 | ||||
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/coherence.rs | 87 | ||||
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/specialize/mod.rs | 20 | ||||
| -rw-r--r-- | compiler/rustc_trait_selection/src/traits/util.rs | 20 | ||||
| -rw-r--r-- | src/test/ui/coherence/coherence-negative-inherent-where-bounds.rs | 25 | ||||
| -rw-r--r-- | src/test/ui/coherence/coherence-negative-inherent.rs | 22 |
9 files changed, 177 insertions, 65 deletions
diff --git a/compiler/rustc_infer/src/infer/at.rs b/compiler/rustc_infer/src/infer/at.rs index 94991fdb201..ff8082840e1 100644 --- a/compiler/rustc_infer/src/infer/at.rs +++ b/compiler/rustc_infer/src/infer/at.rs @@ -28,7 +28,7 @@ use super::*; use rustc_middle::ty::relate::{Relate, TypeRelation}; -use rustc_middle::ty::Const; +use rustc_middle::ty::{Const, ImplSubject}; pub struct At<'a, 'tcx> { pub infcx: &'a InferCtxt<'a, 'tcx>, @@ -272,6 +272,29 @@ impl<'a, 'tcx> Trace<'a, 'tcx> { } } +impl<'tcx> ToTrace<'tcx> for ImplSubject<'tcx> { + fn to_trace( + tcx: TyCtxt<'tcx>, + cause: &ObligationCause<'tcx>, + a_is_expected: bool, + a: Self, + b: Self, + ) -> TypeTrace<'tcx> { + match (a, b) { + (ImplSubject::Trait(trait_ref_a), ImplSubject::Trait(trait_ref_b)) => { + ToTrace::to_trace(tcx, cause, a_is_expected, trait_ref_a, trait_ref_b) + } + (ImplSubject::Inherent(ty_a), ImplSubject::Inherent(ty_b)) => { + ToTrace::to_trace(tcx, cause, a_is_expected, ty_a, ty_b) + } + (ImplSubject::Trait(_), ImplSubject::Inherent(_)) + | (ImplSubject::Inherent(_), ImplSubject::Trait(_)) => { + bug!("can not trace TraitRef and Ty"); + } + } + } +} + impl<'tcx> ToTrace<'tcx> for Ty<'tcx> { fn to_trace( _: TyCtxt<'tcx>, diff --git a/compiler/rustc_middle/src/hir/mod.rs b/compiler/rustc_middle/src/hir/mod.rs index 1053f0cefbe..a9e22d16ee0 100644 --- a/compiler/rustc_middle/src/hir/mod.rs +++ b/compiler/rustc_middle/src/hir/mod.rs @@ -7,10 +7,10 @@ pub mod nested_filter; pub mod place; use crate::ty::query::Providers; -use crate::ty::TyCtxt; +use crate::ty::{ImplSubject, TyCtxt}; use rustc_data_structures::fingerprint::Fingerprint; use rustc_data_structures::stable_hasher::{HashStable, StableHasher}; -use rustc_hir::def_id::LocalDefId; +use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_hir::*; use rustc_query_system::ich::StableHashingContext; use rustc_span::DUMMY_SP; @@ -54,6 +54,12 @@ impl<'tcx> TyCtxt<'tcx> { pub fn parent_module(self, id: HirId) -> LocalDefId { self.parent_module_from_def_id(id.owner) } + + pub fn impl_subject(self, def_id: DefId) -> ImplSubject<'tcx> { + self.impl_trait_ref(def_id) + .map(ImplSubject::Trait) + .unwrap_or_else(|| ImplSubject::Inherent(self.type_of(def_id))) + } } pub fn provide(providers: &mut Providers) { diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs index 3124cc5dba8..31db66dc242 100644 --- a/compiler/rustc_middle/src/ty/mod.rs +++ b/compiler/rustc_middle/src/ty/mod.rs @@ -44,6 +44,7 @@ use rustc_span::symbol::{kw, Ident, Symbol}; use rustc_span::Span; use rustc_target::abi::Align; +use std::fmt::Debug; use std::hash::Hash; use std::ops::ControlFlow; use std::{fmt, str}; @@ -172,6 +173,12 @@ pub struct ImplHeader<'tcx> { pub predicates: Vec<Predicate<'tcx>>, } +#[derive(Copy, Clone, Debug, TypeFoldable)] +pub enum ImplSubject<'tcx> { + Trait(TraitRef<'tcx>), + Inherent(Ty<'tcx>), +} + #[derive( Copy, Clone, diff --git a/compiler/rustc_middle/src/ty/relate.rs b/compiler/rustc_middle/src/ty/relate.rs index 5d6cbcf6907..d9b55563996 100644 --- a/compiler/rustc_middle/src/ty/relate.rs +++ b/compiler/rustc_middle/src/ty/relate.rs @@ -7,7 +7,7 @@ use crate::mir::interpret::{get_slice_bytes, ConstValue, GlobalAlloc, Scalar}; use crate::ty::error::{ExpectedFound, TypeError}; use crate::ty::subst::{GenericArg, GenericArgKind, Subst, SubstsRef}; -use crate::ty::{self, Term, Ty, TyCtxt, TypeFoldable}; +use crate::ty::{self, ImplSubject, Term, Ty, TyCtxt, TypeFoldable}; use rustc_hir as ast; use rustc_hir::def_id::DefId; use rustc_span::DUMMY_SP; @@ -356,6 +356,30 @@ impl<'tcx> Relate<'tcx> for GeneratorWitness<'tcx> { } } +impl<'tcx> Relate<'tcx> for ImplSubject<'tcx> { + #[inline] + fn relate<R: TypeRelation<'tcx>>( + relation: &mut R, + a: ImplSubject<'tcx>, + b: ImplSubject<'tcx>, + ) -> RelateResult<'tcx, ImplSubject<'tcx>> { + match (a, b) { + (ImplSubject::Trait(trait_ref_a), ImplSubject::Trait(trait_ref_b)) => { + let trait_ref = ty::TraitRef::relate(relation, trait_ref_a, trait_ref_b)?; + Ok(ImplSubject::Trait(trait_ref)) + } + (ImplSubject::Inherent(ty_a), ImplSubject::Inherent(ty_b)) => { + let ty = Ty::relate(relation, ty_a, ty_b)?; + Ok(ImplSubject::Inherent(ty)) + } + (ImplSubject::Trait(_), ImplSubject::Inherent(_)) + | (ImplSubject::Inherent(_), ImplSubject::Trait(_)) => { + bug!("can not relate TraitRef and Ty"); + } + } + } +} + impl<'tcx> Relate<'tcx> for Ty<'tcx> { #[inline] fn relate<R: TypeRelation<'tcx>>( diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs index 94a4001bbb9..ec4f8084e21 100644 --- a/compiler/rustc_trait_selection/src/traits/coherence.rs +++ b/compiler/rustc_trait_selection/src/traits/coherence.rs @@ -7,7 +7,7 @@ use crate::infer::outlives::env::OutlivesEnvironment; use crate::infer::{CombinedSnapshot, InferOk, RegionckMode}; use crate::traits::select::IntercrateAmbiguityCause; -use crate::traits::util::impl_trait_ref_and_oblig; +use crate::traits::util::impl_subject_and_oblig; use crate::traits::SkipLeakCheck; use crate::traits::{ self, FulfillmentContext, Normalized, Obligation, ObligationCause, PredicateObligation, @@ -23,9 +23,10 @@ use rustc_middle::traits::specialization_graph::OverlapMode; use rustc_middle::ty::fast_reject::{self, TreatParams}; use rustc_middle::ty::fold::TypeFoldable; use rustc_middle::ty::subst::Subst; -use rustc_middle::ty::{self, Ty, TyCtxt}; +use rustc_middle::ty::{self, ImplSubject, Ty, TyCtxt}; use rustc_span::symbol::sym; use rustc_span::DUMMY_SP; +use std::fmt::Debug; use std::iter; /// Whether we do the orphan check relative to this crate or @@ -300,60 +301,62 @@ fn negative_impl<'cx, 'tcx>( debug!("negative_impl(impl1_def_id={:?}, impl2_def_id={:?})", impl1_def_id, impl2_def_id); let tcx = selcx.infcx().tcx; - // create a parameter environment corresponding to a (placeholder) instantiation of impl1 - let impl1_env = tcx.param_env(impl1_def_id); - let impl1_trait_ref = tcx.impl_trait_ref(impl1_def_id).unwrap(); - // Create an infcx, taking the predicates of impl1 as assumptions: tcx.infer_ctxt().enter(|infcx| { - // Normalize the trait reference. The WF rules ought to ensure - // that this always succeeds. - let impl1_trait_ref = match traits::fully_normalize( + // create a parameter environment corresponding to a (placeholder) instantiation of impl1 + let impl_env = tcx.param_env(impl1_def_id); + let subject1 = match traits::fully_normalize( &infcx, FulfillmentContext::new(), ObligationCause::dummy(), - impl1_env, - impl1_trait_ref, + impl_env, + tcx.impl_subject(impl1_def_id), ) { - Ok(impl1_trait_ref) => impl1_trait_ref, - Err(err) => { - bug!("failed to fully normalize {:?}: {:?}", impl1_trait_ref, err); - } + Ok(s) => s, + Err(err) => bug!("failed to fully normalize {:?}: {:?}", impl1_def_id, err), }; // Attempt to prove that impl2 applies, given all of the above. let selcx = &mut SelectionContext::new(&infcx); let impl2_substs = infcx.fresh_substs_for_item(DUMMY_SP, impl2_def_id); - let (impl2_trait_ref, obligations) = - impl_trait_ref_and_oblig(selcx, impl1_env, impl2_def_id, impl2_substs); - - // do the impls unify? If not, not disjoint. - let Ok(InferOk { obligations: more_obligations, .. }) = infcx - .at(&ObligationCause::dummy(), impl1_env) - .eq(impl1_trait_ref, impl2_trait_ref) - else { - debug!( - "explicit_disjoint: {:?} does not unify with {:?}", - impl1_trait_ref, impl2_trait_ref - ); - return false; - }; + let (subject2, obligations) = + impl_subject_and_oblig(selcx, impl_env, impl2_def_id, impl2_substs); - let opt_failing_obligation = obligations - .into_iter() - .chain(more_obligations) - .find(|o| negative_impl_exists(selcx, impl1_env, impl1_def_id, o)); - - if let Some(failing_obligation) = opt_failing_obligation { - debug!("overlap: obligation unsatisfiable {:?}", failing_obligation); - true - } else { - false - } + !equate(&infcx, impl_env, impl1_def_id, subject1, subject2, obligations) }) } -/// Try to prove that a negative impl exist for the given obligation and their super predicates. +fn equate<'cx, 'tcx>( + infcx: &InferCtxt<'cx, 'tcx>, + impl_env: ty::ParamEnv<'tcx>, + impl1_def_id: DefId, + subject1: ImplSubject<'tcx>, + subject2: ImplSubject<'tcx>, + obligations: impl Iterator<Item = PredicateObligation<'tcx>>, +) -> bool { + // do the impls unify? If not, not disjoint. + let Ok(InferOk { obligations: more_obligations, .. }) = + infcx.at(&ObligationCause::dummy(), impl_env).eq(subject1, subject2) + else { + debug!("explicit_disjoint: {:?} does not unify with {:?}", subject1, subject2); + return true; + }; + + let selcx = &mut SelectionContext::new(&infcx); + let opt_failing_obligation = obligations + .into_iter() + .chain(more_obligations) + .find(|o| negative_impl_exists(selcx, impl_env, impl1_def_id, o)); + + if let Some(failing_obligation) = opt_failing_obligation { + debug!("overlap: obligation unsatisfiable {:?}", failing_obligation); + false + } else { + true + } +} + +/// Try to prove that a negative impl exist for the given obligation and its super predicates. #[instrument(level = "debug", skip(selcx))] fn negative_impl_exists<'cx, 'tcx>( selcx: &SelectionContext<'cx, 'tcx>, @@ -367,7 +370,7 @@ fn negative_impl_exists<'cx, 'tcx>( return true; } - // Try to prove a negative obligation exist for super predicates + // Try to prove a negative obligation exists for super predicates for o in util::elaborate_predicates(infcx.tcx, iter::once(o.predicate)) { if resolve_negative_obligation(infcx, param_env, region_context, &o) { return true; diff --git a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs index 79471065ccc..328e0d2e0e9 100644 --- a/compiler/rustc_trait_selection/src/traits/specialize/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/specialize/mod.rs @@ -20,12 +20,12 @@ use rustc_errors::{struct_span_err, EmissionGuarantee}; use rustc_hir::def_id::{DefId, LocalDefId}; use rustc_middle::lint::LintDiagnosticBuilder; use rustc_middle::ty::subst::{InternalSubsts, Subst, SubstsRef}; -use rustc_middle::ty::{self, TyCtxt}; +use rustc_middle::ty::{self, ImplSubject, TyCtxt}; use rustc_session::lint::builtin::COHERENCE_LEAK_CHECK; use rustc_session::lint::builtin::ORDER_DEPENDENT_TRAIT_OBJECTS; use rustc_span::{Span, DUMMY_SP}; -use super::util::impl_trait_ref_and_oblig; +use super::util; use super::{FulfillmentContext, SelectionContext}; /// Information pertinent to an overlapping impl error. @@ -186,18 +186,20 @@ fn fulfill_implication<'a, 'tcx>( param_env, source_trait_ref, target_impl ); + let source_trait = ImplSubject::Trait(source_trait_ref); + let selcx = &mut SelectionContext::new(&infcx); let target_substs = infcx.fresh_substs_for_item(DUMMY_SP, target_impl); - let (target_trait_ref, obligations) = - impl_trait_ref_and_oblig(selcx, param_env, target_impl, target_substs); + let (target_trait, obligations) = + util::impl_subject_and_oblig(selcx, param_env, target_impl, target_substs); // do the impls unify? If not, no specialization. let Ok(InferOk { obligations: more_obligations, .. }) = - infcx.at(&ObligationCause::dummy(), param_env).eq(source_trait_ref, target_trait_ref) + infcx.at(&ObligationCause::dummy(), param_env).eq(source_trait, target_trait) else { debug!( "fulfill_implication: {:?} does not unify with {:?}", - source_trait_ref, target_trait_ref + source_trait, target_trait ); return Err(()); }; @@ -225,7 +227,7 @@ fn fulfill_implication<'a, 'tcx>( [] => { debug!( "fulfill_implication: an impl for {:?} specializes {:?}", - source_trait_ref, target_trait_ref + source_trait, target_trait ); // Now resolve the *substitution* we built for the target earlier, replacing @@ -237,8 +239,8 @@ fn fulfill_implication<'a, 'tcx>( debug!( "fulfill_implication: for impls on {:?} and {:?}, \ could not fulfill: {:?} given {:?}", - source_trait_ref, - target_trait_ref, + source_trait, + target_trait, errors, param_env.caller_bounds() ); diff --git a/compiler/rustc_trait_selection/src/traits/util.rs b/compiler/rustc_trait_selection/src/traits/util.rs index f800e7a1402..7543d1f9a7b 100644 --- a/compiler/rustc_trait_selection/src/traits/util.rs +++ b/compiler/rustc_trait_selection/src/traits/util.rs @@ -6,7 +6,7 @@ use smallvec::SmallVec; use rustc_data_structures::fx::FxHashSet; use rustc_hir::def_id::DefId; use rustc_middle::ty::subst::{GenericArg, Subst, SubstsRef}; -use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt, TypeFoldable}; +use rustc_middle::ty::{self, ImplSubject, ToPredicate, Ty, TyCtxt, TypeFoldable}; use super::{Normalized, Obligation, ObligationCause, PredicateObligation, SelectionContext}; pub use rustc_infer::traits::{self, util::*}; @@ -190,19 +190,19 @@ impl Iterator for SupertraitDefIds<'_> { // Other /////////////////////////////////////////////////////////////////////////// -/// Instantiate all bound parameters of the impl with the given substs, -/// returning the resulting trait ref and all obligations that arise. +/// Instantiate all bound parameters of the impl subject with the given substs, +/// returning the resulting subject and all obligations that arise. /// The obligations are closed under normalization. -pub fn impl_trait_ref_and_oblig<'a, 'tcx>( +pub fn impl_subject_and_oblig<'a, 'tcx>( selcx: &mut SelectionContext<'a, 'tcx>, param_env: ty::ParamEnv<'tcx>, impl_def_id: DefId, impl_substs: SubstsRef<'tcx>, -) -> (ty::TraitRef<'tcx>, impl Iterator<Item = PredicateObligation<'tcx>>) { - let impl_trait_ref = selcx.tcx().impl_trait_ref(impl_def_id).unwrap(); - let impl_trait_ref = impl_trait_ref.subst(selcx.tcx(), impl_substs); - let Normalized { value: impl_trait_ref, obligations: normalization_obligations1 } = - super::normalize(selcx, param_env, ObligationCause::dummy(), impl_trait_ref); +) -> (ImplSubject<'tcx>, impl Iterator<Item = PredicateObligation<'tcx>>) { + let subject = selcx.tcx().impl_subject(impl_def_id); + let subject = subject.subst(selcx.tcx(), impl_substs); + let Normalized { value: subject, obligations: normalization_obligations1 } = + super::normalize(selcx, param_env, ObligationCause::dummy(), subject); let predicates = selcx.tcx().predicates_of(impl_def_id); let predicates = predicates.instantiate(selcx.tcx(), impl_substs); @@ -215,7 +215,7 @@ pub fn impl_trait_ref_and_oblig<'a, 'tcx>( .chain(normalization_obligations1.into_iter()) .chain(normalization_obligations2.into_iter()); - (impl_trait_ref, impl_obligations) + (subject, impl_obligations) } pub fn predicates_for_generics<'tcx>( diff --git a/src/test/ui/coherence/coherence-negative-inherent-where-bounds.rs b/src/test/ui/coherence/coherence-negative-inherent-where-bounds.rs new file mode 100644 index 00000000000..39ccaa6ac35 --- /dev/null +++ b/src/test/ui/coherence/coherence-negative-inherent-where-bounds.rs @@ -0,0 +1,25 @@ +// check-pass + +#![feature(negative_impls)] +#![feature(rustc_attrs)] +#![feature(with_negative_coherence)] + +trait Foo {} + +impl !Foo for u32 {} + +#[rustc_strict_coherence] +struct MyStruct<T>(T); + +impl MyStruct<u32> { + fn method(&self) {} +} + +impl<T> MyStruct<T> +where + T: Foo, +{ + fn method(&self) {} +} + +fn main() {} diff --git a/src/test/ui/coherence/coherence-negative-inherent.rs b/src/test/ui/coherence/coherence-negative-inherent.rs new file mode 100644 index 00000000000..a9e1acc8044 --- /dev/null +++ b/src/test/ui/coherence/coherence-negative-inherent.rs @@ -0,0 +1,22 @@ +// check-pass + +#![feature(negative_impls)] +#![feature(rustc_attrs)] +#![feature(with_negative_coherence)] + +#[rustc_strict_coherence] +trait Foo {} + +impl !Foo for u32 {} + +struct MyStruct<T>(T); + +impl<T: Foo> MyStruct<T> { + fn method(&self) {} +} + +impl MyStruct<u32> { + fn method(&self) {} +} + +fn main() {} |