diff options
Diffstat (limited to 'compiler')
21 files changed, 627 insertions, 547 deletions
diff --git a/compiler/rustc_infer/src/infer/mod.rs b/compiler/rustc_infer/src/infer/mod.rs index 2d8b47a9cc0..2d87f01ff10 100644 --- a/compiler/rustc_infer/src/infer/mod.rs +++ b/compiler/rustc_infer/src/infer/mod.rs @@ -1032,10 +1032,9 @@ impl<'tcx> InferCtxt<'tcx> { _ => {} } - let ty::SubtypePredicate { a_is_expected, a, b } = - self.instantiate_binder_with_placeholders(predicate); - - Ok(self.at(cause, param_env).sub_exp(DefineOpaqueTypes::No, a_is_expected, a, b)) + self.enter_forall(predicate, |ty::SubtypePredicate { a_is_expected, a, b }| { + Ok(self.at(cause, param_env).sub_exp(DefineOpaqueTypes::No, a_is_expected, a, b)) + }) } pub fn region_outlives_predicate( @@ -1043,10 +1042,12 @@ impl<'tcx> InferCtxt<'tcx> { cause: &traits::ObligationCause<'tcx>, predicate: ty::PolyRegionOutlivesPredicate<'tcx>, ) { - let ty::OutlivesPredicate(r_a, r_b) = self.instantiate_binder_with_placeholders(predicate); - let origin = - SubregionOrigin::from_obligation_cause(cause, || RelateRegionParamBound(cause.span)); - self.sub_regions(origin, r_b, r_a); // `b : a` ==> `a <= b` + self.enter_forall(predicate, |ty::OutlivesPredicate(r_a, r_b)| { + let origin = SubregionOrigin::from_obligation_cause(cause, || { + RelateRegionParamBound(cause.span) + }); + self.sub_regions(origin, r_b, r_a); // `b : a` ==> `a <= b` + }) } /// Number of type variables created so far. @@ -1455,7 +1456,7 @@ impl<'tcx> InferCtxt<'tcx> { // Use this method if you'd like to find some substitution of the binder's // variables (e.g. during a method call). If there isn't a [`BoundRegionConversionTime`] // that corresponds to your use case, consider whether or not you should - // use [`InferCtxt::instantiate_binder_with_placeholders`] instead. + // use [`InferCtxt::enter_forall`] instead. pub fn instantiate_binder_with_fresh_vars<T>( &self, span: Span, diff --git a/compiler/rustc_infer/src/infer/relate/higher_ranked.rs b/compiler/rustc_infer/src/infer/relate/higher_ranked.rs index 440df8c8936..90be80f67b4 100644 --- a/compiler/rustc_infer/src/infer/relate/higher_ranked.rs +++ b/compiler/rustc_infer/src/infer/relate/higher_ranked.rs @@ -38,24 +38,25 @@ impl<'a, 'tcx> CombineFields<'a, 'tcx> { // First, we instantiate each bound region in the supertype with a // fresh placeholder region. Note that this automatically creates // a new universe if needed. - let sup_prime = self.infcx.instantiate_binder_with_placeholders(sup); + self.infcx.enter_forall(sup, |sup_prime| { + // Next, we instantiate each bound region in the subtype + // with a fresh region variable. These region variables -- + // but no other preexisting region variables -- can name + // the placeholders. + let sub_prime = + self.infcx.instantiate_binder_with_fresh_vars(span, HigherRankedType, sub); + debug!("a_prime={:?}", sub_prime); + debug!("b_prime={:?}", sup_prime); - // Next, we instantiate each bound region in the subtype - // with a fresh region variable. These region variables -- - // but no other preexisting region variables -- can name - // the placeholders. - let sub_prime = self.infcx.instantiate_binder_with_fresh_vars(span, HigherRankedType, sub); - - debug!("a_prime={:?}", sub_prime); - debug!("b_prime={:?}", sup_prime); - - // Compare types now that bound regions have been replaced. - let result = self.sub(sub_is_expected).relate(sub_prime, sup_prime)?; - - debug!("OK result={result:?}"); - // NOTE: returning the result here would be dangerous as it contains - // placeholders which **must not** be named afterwards. - Ok(()) + // Compare types now that bound regions have been replaced. + let result = self.sub(sub_is_expected).relate(sub_prime, sup_prime); + if result.is_ok() { + debug!("OK result={result:?}"); + } + // NOTE: returning the result here would be dangerous as it contains + // placeholders which **must not** be named afterwards. + result.map(|_| ()) + }) } } @@ -68,9 +69,11 @@ impl<'tcx> InferCtxt<'tcx> { /// This is the first step of checking subtyping when higher-ranked things are involved. /// For more details visit the relevant sections of the [rustc dev guide]. /// + /// `fn enter_forall` should be preferred over this method. + /// /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/hrtb.html #[instrument(level = "debug", skip(self), ret)] - pub fn instantiate_binder_with_placeholders<T>(&self, binder: ty::Binder<'tcx, T>) -> T + pub fn enter_forall_and_leak_universe<T>(&self, binder: ty::Binder<'tcx, T>) -> T where T: TypeFoldable<TyCtxt<'tcx>> + Copy, { @@ -106,6 +109,31 @@ impl<'tcx> InferCtxt<'tcx> { self.tcx.replace_bound_vars_uncached(binder, delegate) } + /// Replaces all bound variables (lifetimes, types, and constants) bound by + /// `binder` with placeholder variables in a new universe and then calls the + /// closure `f` with the instantiated value. The new placeholders can only be + /// named by inference variables created inside of the closure `f` or afterwards. + /// + /// This is the first step of checking subtyping when higher-ranked things are involved. + /// For more details visit the relevant sections of the [rustc dev guide]. + /// + /// This method should be preferred over `fn enter_forall_and_leak_universe`. + /// + /// [rustc dev guide]: https://rustc-dev-guide.rust-lang.org/traits/hrtb.html + #[instrument(level = "debug", skip(self, f))] + pub fn enter_forall<T, U>(&self, forall: ty::Binder<'tcx, T>, f: impl FnOnce(T) -> U) -> U + where + T: TypeFoldable<TyCtxt<'tcx>> + Copy, + { + // FIXME: currently we do nothing to prevent placeholders with the new universe being + // used after exiting `f`. For example region subtyping can result in outlives constraints + // that name placeholders created in this function. Nested goals from type relations can + // also contain placeholders created by this function. + let value = self.enter_forall_and_leak_universe(forall); + debug!("?value"); + f(value) + } + /// See [RegionConstraintCollector::leak_check][1]. We only check placeholder /// leaking into `outer_universe`, i.e. placeholders which cannot be named by that /// universe. diff --git a/compiler/rustc_infer/src/infer/relate/nll.rs b/compiler/rustc_infer/src/infer/relate/nll.rs index 8b80646a386..5e2d2af9b85 100644 --- a/compiler/rustc_infer/src/infer/relate/nll.rs +++ b/compiler/rustc_infer/src/infer/relate/nll.rs @@ -261,52 +261,55 @@ where Ok(a) } - #[instrument(skip(self), level = "debug")] - fn instantiate_binder_with_placeholders<T>(&mut self, binder: ty::Binder<'tcx, T>) -> T + fn enter_forall<T, U>( + &mut self, + binder: ty::Binder<'tcx, T>, + f: impl FnOnce(&mut Self, T) -> U, + ) -> U where T: ty::TypeFoldable<TyCtxt<'tcx>> + Copy, { - if let Some(inner) = binder.no_bound_vars() { - return inner; - } - - let mut next_region = { - let nll_delegate = &mut self.delegate; - let mut lazy_universe = None; + let value = if let Some(inner) = binder.no_bound_vars() { + inner + } else { + let mut next_region = { + let nll_delegate = &mut self.delegate; + let mut lazy_universe = None; + + move |br: ty::BoundRegion| { + // The first time this closure is called, create a + // new universe for the placeholders we will make + // from here out. + let universe = lazy_universe.unwrap_or_else(|| { + let universe = nll_delegate.create_next_universe(); + lazy_universe = Some(universe); + universe + }); + + let placeholder = ty::PlaceholderRegion { universe, bound: br }; + debug!(?placeholder); + let placeholder_reg = nll_delegate.next_placeholder_region(placeholder); + debug!(?placeholder_reg); + + placeholder_reg + } + }; - move |br: ty::BoundRegion| { - // The first time this closure is called, create a - // new universe for the placeholders we will make - // from here out. - let universe = lazy_universe.unwrap_or_else(|| { - let universe = nll_delegate.create_next_universe(); - lazy_universe = Some(universe); - universe - }); - - let placeholder = ty::PlaceholderRegion { universe, bound: br }; - debug!(?placeholder); - let placeholder_reg = nll_delegate.next_placeholder_region(placeholder); - debug!(?placeholder_reg); - - placeholder_reg - } - }; + let delegate = FnMutDelegate { + regions: &mut next_region, + types: &mut |_bound_ty: ty::BoundTy| { + unreachable!("we only replace regions in nll_relate, not types") + }, + consts: &mut |_bound_var: ty::BoundVar, _ty| { + unreachable!("we only replace regions in nll_relate, not consts") + }, + }; - let delegate = FnMutDelegate { - regions: &mut next_region, - types: &mut |_bound_ty: ty::BoundTy| { - unreachable!("we only replace regions in nll_relate, not types") - }, - consts: &mut |_bound_var: ty::BoundVar, _ty| { - unreachable!("we only replace regions in nll_relate, not consts") - }, + self.infcx.tcx.replace_bound_vars_uncached(binder, delegate) }; - let replaced = self.infcx.tcx.replace_bound_vars_uncached(binder, delegate); - debug!(?replaced); - - replaced + debug!(?value); + f(self, value) } #[instrument(skip(self), level = "debug")] @@ -630,10 +633,10 @@ where // Note: the order here is important. Create the placeholders first, otherwise // we assign the wrong universe to the existential! - let b_replaced = self.instantiate_binder_with_placeholders(b); - let a_replaced = self.instantiate_binder_with_existentials(a); - - self.relate(a_replaced, b_replaced)?; + self.enter_forall(b, |this, b| { + let a = this.instantiate_binder_with_existentials(a); + this.relate(a, b) + })?; self.ambient_variance = variance; } @@ -650,10 +653,10 @@ where let variance = std::mem::replace(&mut self.ambient_variance, ty::Variance::Contravariant); - let a_replaced = self.instantiate_binder_with_placeholders(a); - let b_replaced = self.instantiate_binder_with_existentials(b); - - self.relate(a_replaced, b_replaced)?; + self.enter_forall(a, |this, a| { + let b = this.instantiate_binder_with_existentials(b); + this.relate(a, b) + })?; self.ambient_variance = variance; } diff --git a/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs b/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs index bed5d3c80c0..cf825be7a55 100644 --- a/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs +++ b/compiler/rustc_lint/src/opaque_hidden_inferred_bound.rs @@ -77,101 +77,104 @@ impl<'tcx> LateLintPass<'tcx> for OpaqueHiddenInferredBound { for (pred, pred_span) in cx.tcx.explicit_item_bounds(def_id).instantiate_identity_iter_copied() { - let predicate = infcx.instantiate_binder_with_placeholders(pred.kind()); - let ty::ClauseKind::Projection(proj) = predicate else { - continue; - }; - // Only check types, since those are the only things that may - // have opaques in them anyways. - let Some(proj_term) = proj.term.ty() else { continue }; + infcx.enter_forall(pred.kind(), |predicate| { + let ty::ClauseKind::Projection(proj) = predicate else { + return; + }; + // Only check types, since those are the only things that may + // have opaques in them anyways. + let Some(proj_term) = proj.term.ty() else { return }; - // HACK: `impl Trait<Assoc = impl Trait2>` from an RPIT is "ok"... - if let ty::Alias(ty::Opaque, opaque_ty) = *proj_term.kind() - && cx.tcx.parent(opaque_ty.def_id) == def_id - && matches!( - opaque.origin, - hir::OpaqueTyOrigin::FnReturn(_) | hir::OpaqueTyOrigin::AsyncFn(_) - ) - { - continue; - } + // HACK: `impl Trait<Assoc = impl Trait2>` from an RPIT is "ok"... + if let ty::Alias(ty::Opaque, opaque_ty) = *proj_term.kind() + && cx.tcx.parent(opaque_ty.def_id) == def_id + && matches!( + opaque.origin, + hir::OpaqueTyOrigin::FnReturn(_) | hir::OpaqueTyOrigin::AsyncFn(_) + ) + { + return; + } - // HACK: `async fn() -> Self` in traits is "ok"... - // This is not really that great, but it's similar to why the `-> Self` - // return type is well-formed in traits even when `Self` isn't sized. - if let ty::Param(param_ty) = *proj_term.kind() - && param_ty.name == kw::SelfUpper - && matches!(opaque.origin, hir::OpaqueTyOrigin::AsyncFn(_)) - && opaque.in_trait - { - continue; - } + // HACK: `async fn() -> Self` in traits is "ok"... + // This is not really that great, but it's similar to why the `-> Self` + // return type is well-formed in traits even when `Self` isn't sized. + if let ty::Param(param_ty) = *proj_term.kind() + && param_ty.name == kw::SelfUpper + && matches!(opaque.origin, hir::OpaqueTyOrigin::AsyncFn(_)) + && opaque.in_trait + { + return; + } - let proj_ty = - Ty::new_projection(cx.tcx, proj.projection_ty.def_id, proj.projection_ty.args); - // For every instance of the projection type in the bounds, - // replace them with the term we're assigning to the associated - // type in our opaque type. - let proj_replacer = &mut BottomUpFolder { - tcx: cx.tcx, - ty_op: |ty| if ty == proj_ty { proj_term } else { ty }, - lt_op: |lt| lt, - ct_op: |ct| ct, - }; - // For example, in `impl Trait<Assoc = impl Send>`, for all of the bounds on `Assoc`, - // e.g. `type Assoc: OtherTrait`, replace `<impl Trait as Trait>::Assoc: OtherTrait` - // with `impl Send: OtherTrait`. - for (assoc_pred, assoc_pred_span) in cx - .tcx - .explicit_item_bounds(proj.projection_ty.def_id) - .iter_instantiated_copied(cx.tcx, proj.projection_ty.args) - { - let assoc_pred = assoc_pred.fold_with(proj_replacer); - let Ok(assoc_pred) = traits::fully_normalize( - infcx, - traits::ObligationCause::dummy(), - cx.param_env, - assoc_pred, - ) else { - continue; + let proj_ty = + Ty::new_projection(cx.tcx, proj.projection_ty.def_id, proj.projection_ty.args); + // For every instance of the projection type in the bounds, + // replace them with the term we're assigning to the associated + // type in our opaque type. + let proj_replacer = &mut BottomUpFolder { + tcx: cx.tcx, + ty_op: |ty| if ty == proj_ty { proj_term } else { ty }, + lt_op: |lt| lt, + ct_op: |ct| ct, }; - // If that predicate doesn't hold modulo regions (but passed during type-check), - // then we must've taken advantage of the hack in `project_and_unify_types` where - // we replace opaques with inference vars. Emit a warning! - if !infcx.predicate_must_hold_modulo_regions(&traits::Obligation::new( - cx.tcx, - traits::ObligationCause::dummy(), - cx.param_env, - assoc_pred, - )) { - // If it's a trait bound and an opaque that doesn't satisfy it, - // then we can emit a suggestion to add the bound. - let add_bound = match (proj_term.kind(), assoc_pred.kind().skip_binder()) { - ( - ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }), - ty::ClauseKind::Trait(trait_pred), - ) => Some(AddBound { - suggest_span: cx.tcx.def_span(*def_id).shrink_to_hi(), - trait_ref: trait_pred.print_modifiers_and_trait_path(), - }), - _ => None, + // For example, in `impl Trait<Assoc = impl Send>`, for all of the bounds on `Assoc`, + // e.g. `type Assoc: OtherTrait`, replace `<impl Trait as Trait>::Assoc: OtherTrait` + // with `impl Send: OtherTrait`. + for (assoc_pred, assoc_pred_span) in cx + .tcx + .explicit_item_bounds(proj.projection_ty.def_id) + .iter_instantiated_copied(cx.tcx, proj.projection_ty.args) + { + let assoc_pred = assoc_pred.fold_with(proj_replacer); + let Ok(assoc_pred) = traits::fully_normalize( + infcx, + traits::ObligationCause::dummy(), + cx.param_env, + assoc_pred, + ) else { + continue; }; - cx.emit_span_lint( - OPAQUE_HIDDEN_INFERRED_BOUND, - pred_span, - OpaqueHiddenInferredBoundLint { - ty: Ty::new_opaque( - cx.tcx, - def_id, - ty::GenericArgs::identity_for_item(cx.tcx, def_id), - ), - proj_ty: proj_term, - assoc_pred_span, - add_bound, - }, - ); + + // If that predicate doesn't hold modulo regions (but passed during type-check), + // then we must've taken advantage of the hack in `project_and_unify_types` where + // we replace opaques with inference vars. Emit a warning! + if !infcx.predicate_must_hold_modulo_regions(&traits::Obligation::new( + cx.tcx, + traits::ObligationCause::dummy(), + cx.param_env, + assoc_pred, + )) { + // If it's a trait bound and an opaque that doesn't satisfy it, + // then we can emit a suggestion to add the bound. + let add_bound = match (proj_term.kind(), assoc_pred.kind().skip_binder()) { + ( + ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }), + ty::ClauseKind::Trait(trait_pred), + ) => Some(AddBound { + suggest_span: cx.tcx.def_span(*def_id).shrink_to_hi(), + trait_ref: trait_pred.print_modifiers_and_trait_path(), + }), + _ => None, + }; + + cx.emit_span_lint( + OPAQUE_HIDDEN_INFERRED_BOUND, + pred_span, + OpaqueHiddenInferredBoundLint { + ty: Ty::new_opaque( + cx.tcx, + def_id, + ty::GenericArgs::identity_for_item(cx.tcx, def_id), + ), + proj_ty: proj_term, + assoc_pred_span, + add_bound, + }, + ); + } } - } + }); } } } diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs index 927924452f9..8c734fca9b6 100644 --- a/compiler/rustc_middle/src/ty/sty.rs +++ b/compiler/rustc_middle/src/ty/sty.rs @@ -1052,6 +1052,7 @@ impl<'tcx, T> Binder<'tcx, T> { where T: TypeVisitable<TyCtxt<'tcx>>, { + // `self.value` is equivalent to `self.skip_binder()` if self.value.has_escaping_bound_vars() { None } else { Some(self.skip_binder()) } } diff --git a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs index d02578c4846..8dec04e2c4f 100644 --- a/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs +++ b/compiler/rustc_trait_selection/src/solve/assembly/structural_traits.rs @@ -20,7 +20,7 @@ use crate::solve::EvalCtxt; pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>( ecx: &EvalCtxt<'_, 'tcx>, ty: Ty<'tcx>, -) -> Result<Vec<Ty<'tcx>>, NoSolution> { +) -> Result<Vec<ty::Binder<'tcx, Ty<'tcx>>>, NoSolution> { let tcx = ecx.tcx(); match *ty.kind() { ty::Uint(_) @@ -34,7 +34,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>( | ty::Char => Ok(vec![]), // Treat `str` like it's defined as `struct str([u8]);` - ty::Str => Ok(vec![Ty::new_slice(tcx, tcx.types.u8)]), + ty::Str => Ok(vec![ty::Binder::dummy(Ty::new_slice(tcx, tcx.types.u8))]), ty::Dynamic(..) | ty::Param(..) @@ -47,46 +47,48 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_auto_trait<'tcx>( } ty::RawPtr(ty::TypeAndMut { ty: element_ty, .. }) | ty::Ref(_, element_ty, _) => { - Ok(vec![element_ty]) + Ok(vec![ty::Binder::dummy(element_ty)]) } - ty::Array(element_ty, _) | ty::Slice(element_ty) => Ok(vec![element_ty]), + ty::Array(element_ty, _) | ty::Slice(element_ty) => Ok(vec![ty::Binder::dummy(element_ty)]), ty::Tuple(tys) => { // (T1, ..., Tn) -- meets any bound that all of T1...Tn meet - Ok(tys.iter().collect()) + Ok(tys.iter().map(ty::Binder::dummy).collect()) } - ty::Closure(_, args) => Ok(vec![args.as_closure().tupled_upvars_ty()]), + ty::Closure(_, args) => Ok(vec![ty::Binder::dummy(args.as_closure().tupled_upvars_ty())]), - ty::CoroutineClosure(_, args) => Ok(vec![args.as_coroutine_closure().tupled_upvars_ty()]), + ty::CoroutineClosure(_, args) => { + Ok(vec![ty::Binder::dummy(args.as_coroutine_closure().tupled_upvars_ty())]) + } ty::Coroutine(_, args) => { let coroutine_args = args.as_coroutine(); - Ok(vec![coroutine_args.tupled_upvars_ty(), coroutine_args.witness()]) + Ok(vec![ + ty::Binder::dummy(coroutine_args.tupled_upvars_ty()), + ty::Binder::dummy(coroutine_args.witness()), + ]) } ty::CoroutineWitness(def_id, args) => Ok(ecx .tcx() .coroutine_hidden_types(def_id) - .map(|bty| { - ecx.instantiate_binder_with_placeholders(replace_erased_lifetimes_with_bound_vars( - tcx, - bty.instantiate(tcx, args), - )) - }) + .map(|bty| replace_erased_lifetimes_with_bound_vars(tcx, bty.instantiate(tcx, args))) .collect()), // For `PhantomData<T>`, we pass `T`. - ty::Adt(def, args) if def.is_phantom_data() => Ok(vec![args.type_at(0)]), + ty::Adt(def, args) if def.is_phantom_data() => Ok(vec![ty::Binder::dummy(args.type_at(0))]), - ty::Adt(def, args) => Ok(def.all_fields().map(|f| f.ty(tcx, args)).collect()), + ty::Adt(def, args) => { + Ok(def.all_fields().map(|f| ty::Binder::dummy(f.ty(tcx, args))).collect()) + } ty::Alias(ty::Opaque, ty::AliasTy { def_id, args, .. }) => { // We can resolve the `impl Trait` to its concrete type, // which enforces a DAG between the functions requiring // the auto trait bounds in question. - Ok(vec![tcx.type_of(def_id).instantiate(tcx, args)]) + Ok(vec![ty::Binder::dummy(tcx.type_of(def_id).instantiate(tcx, args))]) } } } @@ -116,7 +118,7 @@ pub(in crate::solve) fn replace_erased_lifetimes_with_bound_vars<'tcx>( pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>( ecx: &EvalCtxt<'_, 'tcx>, ty: Ty<'tcx>, -) -> Result<Vec<Ty<'tcx>>, NoSolution> { +) -> Result<Vec<ty::Binder<'tcx, Ty<'tcx>>>, NoSolution> { match *ty.kind() { ty::Infer(ty::IntVar(_) | ty::FloatVar(_)) | ty::Uint(_) @@ -150,11 +152,11 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>( bug!("unexpected type `{ty}`") } - ty::Tuple(tys) => Ok(tys.to_vec()), + ty::Tuple(tys) => Ok(tys.iter().map(ty::Binder::dummy).collect()), ty::Adt(def, args) => { let sized_crit = def.sized_constraint(ecx.tcx()); - Ok(sized_crit.iter_instantiated(ecx.tcx(), args).collect()) + Ok(sized_crit.iter_instantiated(ecx.tcx(), args).map(ty::Binder::dummy).collect()) } } } @@ -163,7 +165,7 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_sized_trait<'tcx>( pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>( ecx: &EvalCtxt<'_, 'tcx>, ty: Ty<'tcx>, -) -> Result<Vec<Ty<'tcx>>, NoSolution> { +) -> Result<Vec<ty::Binder<'tcx, Ty<'tcx>>>, NoSolution> { match *ty.kind() { ty::FnDef(..) | ty::FnPtr(_) | ty::Error(_) => Ok(vec![]), @@ -194,9 +196,9 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>( bug!("unexpected type `{ty}`") } - ty::Tuple(tys) => Ok(tys.to_vec()), + ty::Tuple(tys) => Ok(tys.iter().map(ty::Binder::dummy).collect()), - ty::Closure(_, args) => Ok(vec![args.as_closure().tupled_upvars_ty()]), + ty::Closure(_, args) => Ok(vec![ty::Binder::dummy(args.as_closure().tupled_upvars_ty())]), ty::CoroutineClosure(..) => Err(NoSolution), @@ -205,7 +207,10 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>( Movability::Movable => { if ecx.tcx().features().coroutine_clone { let coroutine = args.as_coroutine(); - Ok(vec![coroutine.tupled_upvars_ty(), coroutine.witness()]) + Ok(vec![ + ty::Binder::dummy(coroutine.tupled_upvars_ty()), + ty::Binder::dummy(coroutine.witness()), + ]) } else { Err(NoSolution) } @@ -216,10 +221,10 @@ pub(in crate::solve) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>( .tcx() .coroutine_hidden_types(def_id) .map(|bty| { - ecx.instantiate_binder_with_placeholders(replace_erased_lifetimes_with_bound_vars( + replace_erased_lifetimes_with_bound_vars( ecx.tcx(), bty.instantiate(ecx.tcx(), args), - )) + ) }) .collect()), } diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs index 76c50a11102..803379af005 100644 --- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs +++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/mod.rs @@ -477,10 +477,11 @@ impl<'a, 'tcx> EvalCtxt<'a, 'tcx> { } } } else { - let kind = self.infcx.instantiate_binder_with_placeholders(kind); - let goal = goal.with(self.tcx(), ty::Binder::dummy(kind)); - self.add_goal(GoalSource::Misc, goal); - self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + self.infcx.enter_forall(kind, |kind| { + let goal = goal.with(self.tcx(), ty::Binder::dummy(kind)); + self.add_goal(GoalSource::Misc, goal); + self.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) + }) } } @@ -801,13 +802,13 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { ) } - pub(super) fn instantiate_binder_with_placeholders<T: TypeFoldable<TyCtxt<'tcx>> + Copy>( + pub(super) fn enter_forall<T: TypeFoldable<TyCtxt<'tcx>> + Copy, U>( &self, value: ty::Binder<'tcx, T>, - ) -> T { - self.infcx.instantiate_binder_with_placeholders(value) + f: impl FnOnce(T) -> U, + ) -> U { + self.infcx.enter_forall(value, f) } - pub(super) fn resolve_vars_if_possible<T>(&self, value: T) -> T where T: TypeFoldable<TyCtxt<'tcx>>, diff --git a/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs b/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs index 315df06be41..69b69930432 100644 --- a/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs +++ b/compiler/rustc_trait_selection/src/solve/eval_ctxt/select.rs @@ -31,103 +31,108 @@ impl<'tcx> InferCtxtSelectExt<'tcx> for InferCtxt<'tcx> { ) -> SelectionResult<'tcx, Selection<'tcx>> { assert!(self.next_trait_solver()); - let trait_goal = Goal::new( - self.tcx, - obligation.param_env, - self.instantiate_binder_with_placeholders(obligation.predicate), - ); - - let (result, _) = EvalCtxt::enter_root(self, GenerateProofTree::Never, |ecx| { - let goal = Goal::new(ecx.tcx(), trait_goal.param_env, trait_goal.predicate); - let (orig_values, canonical_goal) = ecx.canonicalize_goal(goal); - let mut candidates = ecx.compute_canonical_trait_candidates(canonical_goal); - - // pseudo-winnow - if candidates.len() == 0 { - return Err(SelectionError::Unimplemented); - } else if candidates.len() > 1 { - let mut i = 0; - while i < candidates.len() { - let should_drop_i = (0..candidates.len()).filter(|&j| i != j).any(|j| { - candidate_should_be_dropped_in_favor_of( - ecx.tcx(), - &candidates[i], - &candidates[j], - ) - }); - if should_drop_i { - candidates.swap_remove(i); - } else { - i += 1; - if i > 1 { - return Ok(None); + self.enter_forall(obligation.predicate, |pred| { + let trait_goal = Goal::new(self.tcx, obligation.param_env, pred); + + let (result, _) = EvalCtxt::enter_root(self, GenerateProofTree::Never, |ecx| { + let goal = Goal::new(ecx.tcx(), trait_goal.param_env, trait_goal.predicate); + let (orig_values, canonical_goal) = ecx.canonicalize_goal(goal); + let mut candidates = ecx.compute_canonical_trait_candidates(canonical_goal); + + // pseudo-winnow + if candidates.len() == 0 { + return Err(SelectionError::Unimplemented); + } else if candidates.len() > 1 { + let mut i = 0; + while i < candidates.len() { + let should_drop_i = (0..candidates.len()).filter(|&j| i != j).any(|j| { + candidate_should_be_dropped_in_favor_of( + ecx.tcx(), + &candidates[i], + &candidates[j], + ) + }); + if should_drop_i { + candidates.swap_remove(i); + } else { + i += 1; + if i > 1 { + return Ok(None); + } } } } - } - let candidate = candidates.pop().unwrap(); - let (certainty, nested_goals) = ecx - .instantiate_and_apply_query_response( - trait_goal.param_env, - orig_values, - candidate.result, - ) - .map_err(|_| SelectionError::Unimplemented)?; - - Ok(Some((candidate, certainty, nested_goals))) - }); - - let (candidate, certainty, nested_goals) = match result { - Ok(Some((candidate, certainty, nested_goals))) => (candidate, certainty, nested_goals), - Ok(None) => return Ok(None), - Err(e) => return Err(e), - }; - - let nested_obligations: Vec<_> = nested_goals - .into_iter() - .map(|goal| { - Obligation::new(self.tcx, ObligationCause::dummy(), goal.param_env, goal.predicate) - }) - .collect(); - - let goal = self.resolve_vars_if_possible(trait_goal); - match (certainty, candidate.source) { - // Rematching the implementation will instantiate the same nested goals that - // would have caused the ambiguity, so we can still make progress here regardless. - (_, CandidateSource::Impl(def_id)) => { - rematch_impl(self, goal, def_id, nested_obligations) - } + let candidate = candidates.pop().unwrap(); + let (certainty, nested_goals) = ecx + .instantiate_and_apply_query_response( + trait_goal.param_env, + orig_values, + candidate.result, + ) + .map_err(|_| SelectionError::Unimplemented)?; + + Ok(Some((candidate, certainty, nested_goals))) + }); + + let (candidate, certainty, nested_goals) = match result { + Ok(Some((candidate, certainty, nested_goals))) => { + (candidate, certainty, nested_goals) + } + Ok(None) => return Ok(None), + Err(e) => return Err(e), + }; + + let nested_obligations: Vec<_> = nested_goals + .into_iter() + .map(|goal| { + Obligation::new( + self.tcx, + ObligationCause::dummy(), + goal.param_env, + goal.predicate, + ) + }) + .collect(); + + let goal = self.resolve_vars_if_possible(trait_goal); + match (certainty, candidate.source) { + // Rematching the implementation will instantiate the same nested goals that + // would have caused the ambiguity, so we can still make progress here regardless. + (_, CandidateSource::Impl(def_id)) => { + rematch_impl(self, goal, def_id, nested_obligations) + } - // If an unsize goal is ambiguous, then we can manually rematch it to make - // selection progress for coercion during HIR typeck. If it is *not* ambiguous, - // but is `BuiltinImplSource::Misc`, it may have nested `Unsize` goals, - // and we need to rematch those to detect tuple unsizing and trait upcasting. - // FIXME: This will be wrong if we have param-env or where-clause bounds - // with the unsize goal -- we may need to mark those with different impl - // sources. - (Certainty::Maybe(_), CandidateSource::BuiltinImpl(src)) - | (Certainty::Yes, CandidateSource::BuiltinImpl(src @ BuiltinImplSource::Misc)) - if self.tcx.lang_items().unsize_trait() == Some(goal.predicate.def_id()) => - { - rematch_unsize(self, goal, nested_obligations, src, certainty) - } + // If an unsize goal is ambiguous, then we can manually rematch it to make + // selection progress for coercion during HIR typeck. If it is *not* ambiguous, + // but is `BuiltinImplSource::Misc`, it may have nested `Unsize` goals, + // and we need to rematch those to detect tuple unsizing and trait upcasting. + // FIXME: This will be wrong if we have param-env or where-clause bounds + // with the unsize goal -- we may need to mark those with different impl + // sources. + (Certainty::Maybe(_), CandidateSource::BuiltinImpl(src)) + | (Certainty::Yes, CandidateSource::BuiltinImpl(src @ BuiltinImplSource::Misc)) + if self.tcx.lang_items().unsize_trait() == Some(goal.predicate.def_id()) => + { + rematch_unsize(self, goal, nested_obligations, src, certainty) + } - // Technically some builtin impls have nested obligations, but if - // `Certainty::Yes`, then they should've all been verified and don't - // need re-checking. - (Certainty::Yes, CandidateSource::BuiltinImpl(src)) => { - Ok(Some(ImplSource::Builtin(src, nested_obligations))) - } + // Technically some builtin impls have nested obligations, but if + // `Certainty::Yes`, then they should've all been verified and don't + // need re-checking. + (Certainty::Yes, CandidateSource::BuiltinImpl(src)) => { + Ok(Some(ImplSource::Builtin(src, nested_obligations))) + } - // It's fine not to do anything to rematch these, since there are no - // nested obligations. - (Certainty::Yes, CandidateSource::ParamEnv(_) | CandidateSource::AliasBound) => { - Ok(Some(ImplSource::Param(nested_obligations))) - } + // It's fine not to do anything to rematch these, since there are no + // nested obligations. + (Certainty::Yes, CandidateSource::ParamEnv(_) | CandidateSource::AliasBound) => { + Ok(Some(ImplSource::Param(nested_obligations))) + } - (Certainty::Maybe(_), _) => Ok(None), - } + (Certainty::Maybe(_), _) => Ok(None), + } + }) } } diff --git a/compiler/rustc_trait_selection/src/solve/fulfill.rs b/compiler/rustc_trait_selection/src/solve/fulfill.rs index f08622816ec..63555a305d8 100644 --- a/compiler/rustc_trait_selection/src/solve/fulfill.rs +++ b/compiler/rustc_trait_selection/src/solve/fulfill.rs @@ -140,7 +140,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> { ) } ty::PredicateKind::Subtype(pred) => { - let (a, b) = infcx.instantiate_binder_with_placeholders( + let (a, b) = infcx.enter_forall_and_leak_universe( goal.predicate.kind().rebind((pred.a, pred.b)), ); let expected_found = ExpectedFound::new(true, a, b); @@ -150,7 +150,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> { ) } ty::PredicateKind::Coerce(pred) => { - let (a, b) = infcx.instantiate_binder_with_placeholders( + let (a, b) = infcx.enter_forall_and_leak_universe( goal.predicate.kind().rebind((pred.a, pred.b)), ); let expected_found = ExpectedFound::new(false, a, b); diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs index fd09a6b671d..044832224e5 100644 --- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs +++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs @@ -1049,14 +1049,21 @@ impl<'tcx> EvalCtxt<'_, 'tcx> { fn probe_and_evaluate_goal_for_constituent_tys( &mut self, goal: Goal<'tcx, TraitPredicate<'tcx>>, - constituent_tys: impl Fn(&EvalCtxt<'_, 'tcx>, Ty<'tcx>) -> Result<Vec<Ty<'tcx>>, NoSolution>, + constituent_tys: impl Fn( + &EvalCtxt<'_, 'tcx>, + Ty<'tcx>, + ) -> Result<Vec<ty::Binder<'tcx, Ty<'tcx>>>, NoSolution>, ) -> QueryResult<'tcx> { self.probe_misc_candidate("constituent tys").enter(|ecx| { ecx.add_goals( GoalSource::ImplWhereBound, constituent_tys(ecx, goal.predicate.self_ty())? .into_iter() - .map(|ty| goal.with(ecx.tcx(), goal.predicate.with_self_ty(ecx.tcx(), ty))) + .map(|ty| { + ecx.enter_forall(ty, |ty| { + goal.with(ecx.tcx(), goal.predicate.with_self_ty(ecx.tcx(), ty)) + }) + }) .collect::<Vec<_>>(), ); ecx.evaluate_added_goals_and_make_canonical_response(Certainty::Yes) diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs index 4b20de26219..cbe9a238b1c 100644 --- a/compiler/rustc_trait_selection/src/traits/coherence.rs +++ b/compiler/rustc_trait_selection/src/traits/coherence.rs @@ -971,7 +971,7 @@ impl<'a, 'tcx> ProofTreeVisitor<'tcx> for AmbiguityCausesVisitor<'a, 'tcx> { let Goal { param_env, predicate } = goal.goal(); - // For bound predicates we simply call `infcx.instantiate_binder_with_placeholders` + // For bound predicates we simply call `infcx.enter_forall` // and then prove the resulting predicate as a nested goal. let trait_ref = match predicate.kind().no_bound_vars() { Some(ty::PredicateKind::Clause(ty::ClauseKind::Trait(tr))) => tr.trait_ref, diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs index b246e476bed..c6f5af08013 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs @@ -21,51 +21,62 @@ pub fn recompute_applicable_impls<'tcx>( let impl_may_apply = |impl_def_id| { let ocx = ObligationCtxt::new(infcx); - let placeholder_obligation = - infcx.instantiate_binder_with_placeholders(obligation.predicate); - let obligation_trait_ref = - ocx.normalize(&ObligationCause::dummy(), param_env, placeholder_obligation.trait_ref); - - let impl_args = infcx.fresh_args_for_item(DUMMY_SP, impl_def_id); - let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().instantiate(tcx, impl_args); - let impl_trait_ref = ocx.normalize(&ObligationCause::dummy(), param_env, impl_trait_ref); - - if let Err(_) = - ocx.eq(&ObligationCause::dummy(), param_env, obligation_trait_ref, impl_trait_ref) - { - return false; - } + infcx.enter_forall(obligation.predicate, |placeholder_obligation| { + let obligation_trait_ref = ocx.normalize( + &ObligationCause::dummy(), + param_env, + placeholder_obligation.trait_ref, + ); + + let impl_args = infcx.fresh_args_for_item(DUMMY_SP, impl_def_id); + let impl_trait_ref = + tcx.impl_trait_ref(impl_def_id).unwrap().instantiate(tcx, impl_args); + let impl_trait_ref = + ocx.normalize(&ObligationCause::dummy(), param_env, impl_trait_ref); + + if let Err(_) = + ocx.eq(&ObligationCause::dummy(), param_env, obligation_trait_ref, impl_trait_ref) + { + return false; + } - let impl_predicates = tcx.predicates_of(impl_def_id).instantiate(tcx, impl_args); - ocx.register_obligations(impl_predicates.predicates.iter().map(|&predicate| { - Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate) - })); + let impl_predicates = tcx.predicates_of(impl_def_id).instantiate(tcx, impl_args); + ocx.register_obligations(impl_predicates.predicates.iter().map(|&predicate| { + Obligation::new(tcx, ObligationCause::dummy(), param_env, predicate) + })); - ocx.select_where_possible().is_empty() + ocx.select_where_possible().is_empty() + }) }; let param_env_candidate_may_apply = |poly_trait_predicate: ty::PolyTraitPredicate<'tcx>| { let ocx = ObligationCtxt::new(infcx); - let placeholder_obligation = - infcx.instantiate_binder_with_placeholders(obligation.predicate); - let obligation_trait_ref = - ocx.normalize(&ObligationCause::dummy(), param_env, placeholder_obligation.trait_ref); - - let param_env_predicate = infcx.instantiate_binder_with_fresh_vars( - DUMMY_SP, - BoundRegionConversionTime::HigherRankedType, - poly_trait_predicate, - ); - let param_env_trait_ref = - ocx.normalize(&ObligationCause::dummy(), param_env, param_env_predicate.trait_ref); - - if let Err(_) = - ocx.eq(&ObligationCause::dummy(), param_env, obligation_trait_ref, param_env_trait_ref) - { - return false; - } + infcx.enter_forall(obligation.predicate, |placeholder_obligation| { + let obligation_trait_ref = ocx.normalize( + &ObligationCause::dummy(), + param_env, + placeholder_obligation.trait_ref, + ); + + let param_env_predicate = infcx.instantiate_binder_with_fresh_vars( + DUMMY_SP, + BoundRegionConversionTime::HigherRankedType, + poly_trait_predicate, + ); + let param_env_trait_ref = + ocx.normalize(&ObligationCause::dummy(), param_env, param_env_predicate.trait_ref); + + if let Err(_) = ocx.eq( + &ObligationCause::dummy(), + param_env, + obligation_trait_ref, + param_env_trait_ref, + ) { + return false; + } - ocx.select_where_possible().is_empty() + ocx.select_where_possible().is_empty() + }) }; let mut ambiguities = Vec::new(); diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs index 972da180a33..ceff7187646 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs @@ -64,39 +64,44 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { ) -> Option<(DefId, GenericArgsRef<'tcx>)> { let tcx = self.tcx; let param_env = obligation.param_env; - let trait_ref = self.instantiate_binder_with_placeholders(trait_ref); - let trait_self_ty = trait_ref.self_ty(); + self.enter_forall(trait_ref, |trait_ref| { + let trait_self_ty = trait_ref.self_ty(); - let mut self_match_impls = vec![]; - let mut fuzzy_match_impls = vec![]; + let mut self_match_impls = vec![]; + let mut fuzzy_match_impls = vec![]; - self.tcx.for_each_relevant_impl(trait_ref.def_id, trait_self_ty, |def_id| { - let impl_args = self.fresh_args_for_item(obligation.cause.span, def_id); - let impl_trait_ref = tcx.impl_trait_ref(def_id).unwrap().instantiate(tcx, impl_args); + self.tcx.for_each_relevant_impl(trait_ref.def_id, trait_self_ty, |def_id| { + let impl_args = self.fresh_args_for_item(obligation.cause.span, def_id); + let impl_trait_ref = + tcx.impl_trait_ref(def_id).unwrap().instantiate(tcx, impl_args); - let impl_self_ty = impl_trait_ref.self_ty(); + let impl_self_ty = impl_trait_ref.self_ty(); - if self.can_eq(param_env, trait_self_ty, impl_self_ty) { - self_match_impls.push((def_id, impl_args)); + if self.can_eq(param_env, trait_self_ty, impl_self_ty) { + self_match_impls.push((def_id, impl_args)); - if iter::zip(trait_ref.args.types().skip(1), impl_trait_ref.args.types().skip(1)) + if iter::zip( + trait_ref.args.types().skip(1), + impl_trait_ref.args.types().skip(1), + ) .all(|(u, v)| self.fuzzy_match_tys(u, v, false).is_some()) - { - fuzzy_match_impls.push((def_id, impl_args)); + { + fuzzy_match_impls.push((def_id, impl_args)); + } } - } - }); + }); - let impl_def_id_and_args = if self_match_impls.len() == 1 { - self_match_impls[0] - } else if fuzzy_match_impls.len() == 1 { - fuzzy_match_impls[0] - } else { - return None; - }; + let impl_def_id_and_args = if self_match_impls.len() == 1 { + self_match_impls[0] + } else if fuzzy_match_impls.len() == 1 { + fuzzy_match_impls[0] + } else { + return None; + }; - tcx.has_attr(impl_def_id_and_args.0, sym::rustc_on_unimplemented) - .then_some(impl_def_id_and_args) + tcx.has_attr(impl_def_id_and_args.0, sym::rustc_on_unimplemented) + .then_some(impl_def_id_and_args) + }) } /// Used to set on_unimplemented's `ItemContext` diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs index a4d8cbb125c..f68200b6f4d 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs @@ -1248,52 +1248,55 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { trait_pred: ty::PolyTraitPredicate<'tcx>, ) -> bool { let self_ty = self.resolve_vars_if_possible(trait_pred.self_ty()); - let ty = self.instantiate_binder_with_placeholders(self_ty); - let Some(generics) = self.tcx.hir().get_generics(obligation.cause.body_id) else { - return false; - }; - let ty::Ref(_, inner_ty, hir::Mutability::Not) = ty.kind() else { return false }; - let ty::Param(param) = inner_ty.kind() else { return false }; - let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } = - obligation.cause.code() - else { - return false; - }; - let arg_node = self.tcx.hir_node(*arg_hir_id); - let Node::Expr(Expr { kind: hir::ExprKind::Path(_), .. }) = arg_node else { return false }; + self.enter_forall(self_ty, |ty: Ty<'_>| { + let Some(generics) = self.tcx.hir().get_generics(obligation.cause.body_id) else { + return false; + }; + let ty::Ref(_, inner_ty, hir::Mutability::Not) = ty.kind() else { return false }; + let ty::Param(param) = inner_ty.kind() else { return false }; + let ObligationCauseCode::FunctionArgumentObligation { arg_hir_id, .. } = + obligation.cause.code() + else { + return false; + }; + let arg_node = self.tcx.hir_node(*arg_hir_id); + let Node::Expr(Expr { kind: hir::ExprKind::Path(_), .. }) = arg_node else { + return false; + }; - let clone_trait = self.tcx.require_lang_item(LangItem::Clone, None); - let has_clone = |ty| { - self.type_implements_trait(clone_trait, [ty], obligation.param_env) - .must_apply_modulo_regions() - }; + let clone_trait = self.tcx.require_lang_item(LangItem::Clone, None); + let has_clone = |ty| { + self.type_implements_trait(clone_trait, [ty], obligation.param_env) + .must_apply_modulo_regions() + }; - let new_obligation = self.mk_trait_obligation_with_new_self_ty( - obligation.param_env, - trait_pred.map_bound(|trait_pred| (trait_pred, *inner_ty)), - ); + let new_obligation = self.mk_trait_obligation_with_new_self_ty( + obligation.param_env, + trait_pred.map_bound(|trait_pred| (trait_pred, *inner_ty)), + ); - if self.predicate_may_hold(&new_obligation) && has_clone(ty) { - if !has_clone(param.to_ty(self.tcx)) { - suggest_constraining_type_param( - self.tcx, - generics, - err, - param.name.as_str(), - "Clone", - Some(clone_trait), - None, + if self.predicate_may_hold(&new_obligation) && has_clone(ty) { + if !has_clone(param.to_ty(self.tcx)) { + suggest_constraining_type_param( + self.tcx, + generics, + err, + param.name.as_str(), + "Clone", + Some(clone_trait), + None, + ); + } + err.span_suggestion_verbose( + obligation.cause.span.shrink_to_hi(), + "consider using clone here", + ".clone()".to_string(), + Applicability::MaybeIncorrect, ); + return true; } - err.span_suggestion_verbose( - obligation.cause.span.shrink_to_hi(), - "consider using clone here", - ".clone()", - Applicability::MaybeIncorrect, - ); - return true; - } - false + false + }) } /// Extracts information about a callable type for diagnostics. This is a @@ -4038,26 +4041,27 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if let Some(where_pred) = where_pred.as_trait_clause() && let Some(failed_pred) = failed_pred.to_opt_poly_trait_pred() { - let where_pred = self.instantiate_binder_with_placeholders(where_pred); - let failed_pred = self.instantiate_binder_with_fresh_vars( - expr.span, - BoundRegionConversionTime::FnCall, - failed_pred, - ); + self.enter_forall(where_pred, |where_pred| { + let failed_pred = self.instantiate_binder_with_fresh_vars( + expr.span, + BoundRegionConversionTime::FnCall, + failed_pred, + ); - let zipped = iter::zip(where_pred.trait_ref.args, failed_pred.trait_ref.args); - for (expected, actual) in zipped { - self.probe(|_| { - match self.at(&ObligationCause::misc(expr.span, body_id), param_env).eq( - DefineOpaqueTypes::No, - expected, - actual, - ) { - Ok(_) => (), // We ignore nested obligations here for now. - Err(err) => type_diffs.push(err), - } - }) - } + let zipped = + iter::zip(where_pred.trait_ref.args, failed_pred.trait_ref.args); + for (expected, actual) in zipped { + self.probe(|_| { + match self + .at(&ObligationCause::misc(expr.span, body_id), param_env) + .eq(DefineOpaqueTypes::No, expected, actual) + { + Ok(_) => (), // We ignore nested obligations here for now. + Err(err) => type_diffs.push(err), + } + }) + } + }) } else if let Some(where_pred) = where_pred.as_projection_clause() && let Some(failed_pred) = failed_pred.to_opt_poly_projection_pred() && let Some(found) = failed_pred.skip_binder().term.ty() @@ -4614,14 +4618,15 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { { self.probe(|_| { let ocx = ObligationCtxt::new(self); - let pred = self.instantiate_binder_with_placeholders(pred); - let pred = ocx.normalize(&ObligationCause::dummy(), param_env, pred); - ocx.register_obligation(Obligation::new( - self.tcx, - ObligationCause::dummy(), - param_env, - pred, - )); + self.enter_forall(pred, |pred| { + let pred = ocx.normalize(&ObligationCause::dummy(), param_env, pred); + ocx.register_obligation(Obligation::new( + self.tcx, + ObligationCause::dummy(), + param_env, + pred, + )); + }); if !ocx.select_where_possible().is_empty() { // encountered errors. return; @@ -4768,13 +4773,13 @@ fn hint_missing_borrow<'tcx>( } let found_args = match found.kind() { - ty::FnPtr(f) => infcx.instantiate_binder_with_placeholders(*f).inputs().iter(), + ty::FnPtr(f) => infcx.enter_forall(*f, |f| f.inputs().iter()), kind => { span_bug!(span, "found was converted to a FnPtr above but is now {:?}", kind) } }; let expected_args = match expected.kind() { - ty::FnPtr(f) => infcx.instantiate_binder_with_placeholders(*f).inputs().iter(), + ty::FnPtr(f) => infcx.enter_forall(*f, |f| f.inputs().iter()), kind => { span_bug!(span, "expected was converted to a FnPtr above but is now {:?}", kind) } diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs index e9f932a8300..07e4fef9dd4 100644 --- a/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs +++ b/compiler/rustc_trait_selection/src/traits/error_reporting/type_err_ctxt_ext.rs @@ -1305,12 +1305,13 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> { let mut pred = obligation.predicate.to_opt_poly_trait_pred(); while let Some((next_code, next_pred)) = code.parent() { if let Some(pred) = pred { - let pred = self.instantiate_binder_with_placeholders(pred); - diag.note(format!( - "`{}` must implement `{}`, but it does not", - pred.self_ty(), - pred.print_modifiers_and_trait_path() - )); + self.enter_forall(pred, |pred| { + diag.note(format!( + "`{}` must implement `{}`, but it does not", + pred.self_ty(), + pred.print_modifiers_and_trait_path() + )); + }) } code = next_code; pred = next_pred; @@ -2015,70 +2016,78 @@ impl<'tcx> InferCtxtPrivExt<'tcx> for TypeErrCtxt<'_, 'tcx> { if let [single] = &impl_candidates { if self.probe(|_| { let ocx = ObligationCtxt::new(self); - let obligation_trait_ref = self.instantiate_binder_with_placeholders(trait_ref); - let impl_args = self.fresh_args_for_item(DUMMY_SP, single.impl_def_id); - let impl_trait_ref = ocx.normalize( - &ObligationCause::dummy(), - param_env, - ty::EarlyBinder::bind(single.trait_ref).instantiate(self.tcx, impl_args), - ); - ocx.register_obligations( - self.tcx - .predicates_of(single.impl_def_id) - .instantiate(self.tcx, impl_args) - .into_iter() - .map(|(clause, _)| { - Obligation::new(self.tcx, ObligationCause::dummy(), param_env, clause) - }), - ); - if !ocx.select_where_possible().is_empty() { - return false; - } + self.enter_forall(trait_ref, |obligation_trait_ref| { + let impl_args = self.fresh_args_for_item(DUMMY_SP, single.impl_def_id); + let impl_trait_ref = ocx.normalize( + &ObligationCause::dummy(), + param_env, + ty::EarlyBinder::bind(single.trait_ref).instantiate(self.tcx, impl_args), + ); - let mut terrs = vec![]; - for (obligation_arg, impl_arg) in - std::iter::zip(obligation_trait_ref.args, impl_trait_ref.args) - { - if let Err(terr) = - ocx.eq(&ObligationCause::dummy(), param_env, impl_arg, obligation_arg) - { - terrs.push(terr); - } + ocx.register_obligations( + self.tcx + .predicates_of(single.impl_def_id) + .instantiate(self.tcx, impl_args) + .into_iter() + .map(|(clause, _)| { + Obligation::new( + self.tcx, + ObligationCause::dummy(), + param_env, + clause, + ) + }), + ); if !ocx.select_where_possible().is_empty() { return false; } - } - // Literally nothing unified, just give up. - if terrs.len() == impl_trait_ref.args.len() { - return false; - } + let mut terrs = vec![]; + for (obligation_arg, impl_arg) in + std::iter::zip(obligation_trait_ref.args, impl_trait_ref.args) + { + if let Err(terr) = + ocx.eq(&ObligationCause::dummy(), param_env, impl_arg, obligation_arg) + { + terrs.push(terr); + } + if !ocx.select_where_possible().is_empty() { + return false; + } + } - let cand = - self.resolve_vars_if_possible(impl_trait_ref).fold_with(&mut BottomUpFolder { - tcx: self.tcx, - ty_op: |ty| ty, - lt_op: |lt| lt, - ct_op: |ct| ct.normalize(self.tcx, ty::ParamEnv::empty()), - }); - err.highlighted_help(vec![ - StringPart::normal(format!("the trait `{}` ", cand.print_trait_sugared())), - StringPart::highlighted("is"), - StringPart::normal(" implemented for `"), - StringPart::highlighted(cand.self_ty().to_string()), - StringPart::normal("`"), - ]); + // Literally nothing unified, just give up. + if terrs.len() == impl_trait_ref.args.len() { + return false; + } - if let [TypeError::Sorts(exp_found)] = &terrs[..] { - let exp_found = self.resolve_vars_if_possible(*exp_found); - err.help(format!( - "for that trait implementation, expected `{}`, found `{}`", - exp_found.expected, exp_found.found - )); - } + let cand = self.resolve_vars_if_possible(impl_trait_ref).fold_with( + &mut BottomUpFolder { + tcx: self.tcx, + ty_op: |ty| ty, + lt_op: |lt| lt, + ct_op: |ct| ct.normalize(self.tcx, ty::ParamEnv::empty()), + }, + ); + err.highlighted_help(vec![ + StringPart::normal(format!("the trait `{}` ", cand.print_trait_sugared())), + StringPart::highlighted("is"), + StringPart::normal(" implemented for `"), + StringPart::highlighted(cand.self_ty().to_string()), + StringPart::normal("`"), + ]); + + if let [TypeError::Sorts(exp_found)] = &terrs[..] { + let exp_found = self.resolve_vars_if_possible(*exp_found); + err.help(format!( + "for that trait implementation, expected `{}`, found `{}`", + exp_found.expected, exp_found.found + )); + } - true + true + }) }) { return true; } diff --git a/compiler/rustc_trait_selection/src/traits/fulfill.rs b/compiler/rustc_trait_selection/src/traits/fulfill.rs index 0337672b302..5ef7a202a12 100644 --- a/compiler/rustc_trait_selection/src/traits/fulfill.rs +++ b/compiler/rustc_trait_selection/src/traits/fulfill.rs @@ -358,8 +358,7 @@ impl<'a, 'tcx> ObligationProcessor for FulfillProcessor<'a, 'tcx> { | ty::PredicateKind::Coerce(_) | ty::PredicateKind::Clause(ty::ClauseKind::ConstEvaluatable(..)) | ty::PredicateKind::ConstEquate(..) => { - let pred = - ty::Binder::dummy(infcx.instantiate_binder_with_placeholders(binder)); + let pred = ty::Binder::dummy(infcx.enter_forall_and_leak_universe(binder)); ProcessResult::Changed(mk_pending(vec![obligation.with(infcx.tcx, pred)])) } ty::PredicateKind::Ambiguous => ProcessResult::Unchanged, diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs index 955c81eee6b..fd8306bbc0b 100644 --- a/compiler/rustc_trait_selection/src/traits/project.rs +++ b/compiler/rustc_trait_selection/src/traits/project.rs @@ -250,8 +250,7 @@ pub(super) fn poly_project_and_unify_type<'cx, 'tcx>( let infcx = selcx.infcx; let r = infcx.commit_if_ok(|_snapshot| { let old_universe = infcx.universe(); - let placeholder_predicate = - infcx.instantiate_binder_with_placeholders(obligation.predicate); + let placeholder_predicate = infcx.enter_forall_and_leak_universe(obligation.predicate); let new_universe = infcx.universe(); let placeholder_obligation = obligation.with(infcx.tcx, placeholder_predicate); diff --git a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs index 2258e796103..d056dd51f50 100644 --- a/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs +++ b/compiler/rustc_trait_selection/src/traits/select/candidate_assembly.rs @@ -728,64 +728,63 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { self.infcx.probe(|_snapshot| { let poly_trait_predicate = self.infcx.resolve_vars_if_possible(obligation.predicate); - let placeholder_trait_predicate = - self.infcx.instantiate_binder_with_placeholders(poly_trait_predicate); - - let self_ty = placeholder_trait_predicate.self_ty(); - let principal_trait_ref = match self_ty.kind() { - ty::Dynamic(data, ..) => { - if data.auto_traits().any(|did| did == obligation.predicate.def_id()) { - debug!( - "assemble_candidates_from_object_ty: matched builtin bound, \ + self.infcx.enter_forall(poly_trait_predicate, |placeholder_trait_predicate| { + let self_ty = placeholder_trait_predicate.self_ty(); + let principal_trait_ref = match self_ty.kind() { + ty::Dynamic(data, ..) => { + if data.auto_traits().any(|did| did == obligation.predicate.def_id()) { + debug!( + "assemble_candidates_from_object_ty: matched builtin bound, \ pushing candidate" - ); - candidates.vec.push(BuiltinObjectCandidate); - return; - } + ); + candidates.vec.push(BuiltinObjectCandidate); + return; + } - if let Some(principal) = data.principal() { - if !self.infcx.tcx.features().object_safe_for_dispatch { - principal.with_self_ty(self.tcx(), self_ty) - } else if self.tcx().check_is_object_safe(principal.def_id()) { - principal.with_self_ty(self.tcx(), self_ty) + if let Some(principal) = data.principal() { + if !self.infcx.tcx.features().object_safe_for_dispatch { + principal.with_self_ty(self.tcx(), self_ty) + } else if self.tcx().check_is_object_safe(principal.def_id()) { + principal.with_self_ty(self.tcx(), self_ty) + } else { + return; + } } else { + // Only auto trait bounds exist. return; } - } else { - // Only auto trait bounds exist. + } + ty::Infer(ty::TyVar(_)) => { + debug!("assemble_candidates_from_object_ty: ambiguous"); + candidates.ambiguous = true; // could wind up being an object type return; } - } - ty::Infer(ty::TyVar(_)) => { - debug!("assemble_candidates_from_object_ty: ambiguous"); - candidates.ambiguous = true; // could wind up being an object type - return; - } - _ => return, - }; - - debug!(?principal_trait_ref, "assemble_candidates_from_object_ty"); - - // Count only those upcast versions that match the trait-ref - // we are looking for. Specifically, do not only check for the - // correct trait, but also the correct type parameters. - // For example, we may be trying to upcast `Foo` to `Bar<i32>`, - // but `Foo` is declared as `trait Foo: Bar<u32>`. - let candidate_supertraits = util::supertraits(self.tcx(), principal_trait_ref) - .enumerate() - .filter(|&(_, upcast_trait_ref)| { - self.infcx.probe(|_| { - self.match_normalize_trait_ref( - obligation, - upcast_trait_ref, - placeholder_trait_predicate.trait_ref, - ) - .is_ok() + _ => return, + }; + + debug!(?principal_trait_ref, "assemble_candidates_from_object_ty"); + + // Count only those upcast versions that match the trait-ref + // we are looking for. Specifically, do not only check for the + // correct trait, but also the correct type parameters. + // For example, we may be trying to upcast `Foo` to `Bar<i32>`, + // but `Foo` is declared as `trait Foo: Bar<u32>`. + let candidate_supertraits = util::supertraits(self.tcx(), principal_trait_ref) + .enumerate() + .filter(|&(_, upcast_trait_ref)| { + self.infcx.probe(|_| { + self.match_normalize_trait_ref( + obligation, + upcast_trait_ref, + placeholder_trait_predicate.trait_ref, + ) + .is_ok() + }) }) - }) - .map(|(idx, _)| ObjectCandidate(idx)); + .map(|(idx, _)| ObjectCandidate(idx)); - candidates.vec.extend(candidate_supertraits); + candidates.vec.extend(candidate_supertraits); + }) }) } diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs index c9d06b0f675..f0c49253dbd 100644 --- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs +++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs @@ -159,7 +159,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let trait_predicate = self.infcx.shallow_resolve(obligation.predicate); let placeholder_trait_predicate = - self.infcx.instantiate_binder_with_placeholders(trait_predicate).trait_ref; + self.infcx.enter_forall_and_leak_universe(trait_predicate).trait_ref; let placeholder_self_ty = placeholder_trait_predicate.self_ty(); let placeholder_trait_predicate = ty::Binder::dummy(placeholder_trait_predicate); let (def_id, args) = match *placeholder_self_ty.kind() { @@ -402,7 +402,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let cause = obligation.derived_cause(BuiltinDerivedObligation); let poly_trait_ref = obligation.predicate.to_poly_trait_ref(); - let trait_ref = self.infcx.instantiate_binder_with_placeholders(poly_trait_ref); + let trait_ref = self.infcx.enter_forall_and_leak_universe(poly_trait_ref); let trait_obligations: Vec<PredicateObligation<'_>> = self.impl_or_trait_obligations( &cause, obligation.recursion_depth + 1, @@ -493,7 +493,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let tcx = self.tcx(); debug!(?obligation, ?index, "confirm_object_candidate"); - let trait_predicate = self.infcx.instantiate_binder_with_placeholders(obligation.predicate); + let trait_predicate = self.infcx.enter_forall_and_leak_universe(obligation.predicate); let self_ty = self.infcx.shallow_resolve(trait_predicate.self_ty()); let obligation_trait_ref = ty::Binder::dummy(trait_predicate.trait_ref); let ty::Dynamic(data, ..) = *self_ty.kind() else { @@ -691,7 +691,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { let cause = obligation.derived_cause(BuiltinDerivedObligation); // Confirm the `type Output: Sized;` bound that is present on `FnOnce` - let output_ty = self.infcx.instantiate_binder_with_placeholders(sig.output()); + let output_ty = self.infcx.enter_forall_and_leak_universe(sig.output()); let output_ty = normalize_with_depth_to( self, obligation.param_env, @@ -712,7 +712,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ) -> Vec<PredicateObligation<'tcx>> { debug!(?obligation, "confirm_trait_alias_candidate"); - let predicate = self.infcx.instantiate_binder_with_placeholders(obligation.predicate); + let predicate = self.infcx.enter_forall_and_leak_universe(obligation.predicate); let trait_ref = predicate.trait_ref; let trait_def_id = trait_ref.def_id; let args = trait_ref.args; diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs index 7f41c73b72f..14192c6ddd3 100644 --- a/compiler/rustc_trait_selection/src/traits/select/mod.rs +++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs @@ -1606,7 +1606,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> { ) -> smallvec::SmallVec<[usize; 2]> { let poly_trait_predicate = self.infcx.resolve_vars_if_possible(obligation.predicate); let placeholder_trait_predicate = - self.infcx.instantiate_binder_with_placeholders(poly_trait_predicate); + self.infcx.enter_forall_and_leak_universe(poly_trait_predicate); debug!(?placeholder_trait_predicate); let tcx = self.infcx.tcx; @@ -2386,7 +2386,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { .flat_map(|ty| { let ty: ty::Binder<'tcx, Ty<'tcx>> = types.rebind(*ty); // <----/ - let placeholder_ty = self.infcx.instantiate_binder_with_placeholders(ty); + let placeholder_ty = self.infcx.enter_forall_and_leak_universe(ty); let Normalized { value: normalized_ty, mut obligations } = ensure_sufficient_stack(|| { project::normalize_with_depth( @@ -2472,7 +2472,7 @@ impl<'tcx> SelectionContext<'_, 'tcx> { obligation: &PolyTraitObligation<'tcx>, ) -> Result<Normalized<'tcx, GenericArgsRef<'tcx>>, ()> { let placeholder_obligation = - self.infcx.instantiate_binder_with_placeholders(obligation.predicate); + self.infcx.enter_forall_and_leak_universe(obligation.predicate); let placeholder_obligation_trait_ref = placeholder_obligation.trait_ref; let impl_args = self.infcx.fresh_args_for_item(obligation.cause.span, impl_def_id); diff --git a/compiler/rustc_type_ir/src/region_kind.rs b/compiler/rustc_type_ir/src/region_kind.rs index 3b5e41e8d85..777c649fabd 100644 --- a/compiler/rustc_type_ir/src/region_kind.rs +++ b/compiler/rustc_type_ir/src/region_kind.rs @@ -163,8 +163,7 @@ pub enum RegionKind<I: Interner> { /// A placeholder region -- the higher-ranked version of `ReLateParam`. /// Should not exist outside of type inference. /// - /// Used when instantiating a `forall` binder via - /// `infcx.instantiate_binder_with_placeholders`. + /// Used when instantiating a `forall` binder via `infcx.enter_forall`. RePlaceholder(I::PlaceholderRegion), /// Erased region, used by trait selection, in MIR and during codegen. |