diff options
5 files changed, 283 insertions, 56 deletions
diff --git a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs index 3048c175e1e..76edeccaf29 100644 --- a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs +++ b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs @@ -19,7 +19,7 @@ use rustc_middle::ty::{ self, InternalSubsts, Ty, TypeFoldable, TypeFolder, TypeSuperFoldable, TypeVisitableExt, }; use rustc_middle::ty::{GenericParamDefKind, ToPredicate, TyCtxt}; -use rustc_span::Span; +use rustc_span::{Span, DUMMY_SP}; use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt; use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _; use rustc_trait_selection::traits::{ @@ -651,11 +651,7 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( let impl_sig = ocx.normalize( &norm_cause, param_env, - infcx.instantiate_binder_with_fresh_vars( - return_span, - infer::HigherRankedType, - tcx.fn_sig(impl_m.def_id).subst_identity(), - ), + tcx.liberate_late_bound_regions(impl_m.def_id, tcx.fn_sig(impl_m.def_id).subst_identity()), ); impl_sig.error_reported()?; let impl_return_ty = impl_sig.output(); @@ -665,9 +661,10 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( // them with inference variables. // We will use these inference variables to collect the hidden types of RPITITs. let mut collector = ImplTraitInTraitCollector::new(&ocx, return_span, param_env, impl_m_def_id); - let unnormalized_trait_sig = tcx - .liberate_late_bound_regions( - impl_m.def_id, + let unnormalized_trait_sig = infcx + .instantiate_binder_with_fresh_vars( + return_span, + infer::HigherRankedType, tcx.fn_sig(trait_m.def_id).subst(tcx, trait_to_placeholder_substs), ) .fold_with(&mut collector); @@ -760,15 +757,17 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( let mut collected_tys = FxHashMap::default(); for (def_id, (ty, substs)) in collected_types { - match infcx.fully_resolve(ty) { - Ok(ty) => { + match infcx.fully_resolve((ty, substs)) { + Ok((ty, substs)) => { // `ty` contains free regions that we created earlier while liberating the // trait fn signature. However, projection normalization expects `ty` to // contains `def_id`'s early-bound regions. let id_substs = InternalSubsts::identity_for_item(tcx, def_id); debug!(?id_substs, ?substs); - let map: FxHashMap<ty::GenericArg<'tcx>, ty::GenericArg<'tcx>> = - std::iter::zip(substs, id_substs).collect(); + let map: FxHashMap<_, _> = std::iter::zip(substs, id_substs) + .skip(tcx.generics_of(trait_m.def_id).count()) + .filter_map(|(a, b)| Some((a.as_region()?, b.as_region()?))) + .collect(); debug!(?map); // NOTE(compiler-errors): RPITITs, like all other RPITs, have early-bound @@ -793,25 +792,19 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( // same generics. let num_trait_substs = trait_to_impl_substs.len(); let num_impl_substs = tcx.generics_of(impl_m.container_id(tcx)).params.len(); - let ty = tcx.fold_regions(ty, |region, _| { - match region.kind() { - // Remap all free regions, which correspond to late-bound regions in the function. - ty::ReFree(_) => {} - // Remap early-bound regions as long as they don't come from the `impl` itself. - ty::ReEarlyBound(ebr) if tcx.parent(ebr.def_id) != impl_m.container_id(tcx) => {} - _ => return region, - } - let Some(ty::ReEarlyBound(e)) = map.get(®ion.into()).map(|r| r.expect_region().kind()) - else { - return ty::Region::new_error_with_message(tcx, return_span, "expected ReFree to map to ReEarlyBound") - }; - ty::Region::new_early_bound(tcx, ty::EarlyBoundRegion { - def_id: e.def_id, - name: e.name, - index: (e.index as usize - num_trait_substs + num_impl_substs) as u32, - }) - }); - debug!(%ty); + let ty = match ty.try_fold_with(&mut RemapHiddenTyRegions { + tcx, + map, + num_trait_substs, + num_impl_substs, + def_id, + impl_def_id: impl_m.container_id(tcx), + ty, + return_span, + }) { + Ok(ty) => ty, + Err(guar) => tcx.ty_error(guar), + }; collected_tys.insert(def_id, ty::EarlyBinder::bind(ty)); } Err(err) => { @@ -895,6 +888,97 @@ impl<'tcx> TypeFolder<TyCtxt<'tcx>> for ImplTraitInTraitCollector<'_, 'tcx> { } } +struct RemapHiddenTyRegions<'tcx> { + tcx: TyCtxt<'tcx>, + map: FxHashMap<ty::Region<'tcx>, ty::Region<'tcx>>, + num_trait_substs: usize, + num_impl_substs: usize, + def_id: DefId, + impl_def_id: DefId, + ty: Ty<'tcx>, + return_span: Span, +} + +impl<'tcx> ty::FallibleTypeFolder<TyCtxt<'tcx>> for RemapHiddenTyRegions<'tcx> { + type Error = ErrorGuaranteed; + + fn interner(&self) -> TyCtxt<'tcx> { + self.tcx + } + + fn try_fold_ty(&mut self, t: Ty<'tcx>) -> Result<Ty<'tcx>, Self::Error> { + if let ty::Alias(ty::Opaque, ty::AliasTy { substs, def_id, .. }) = *t.kind() { + let mut mapped_substs = Vec::with_capacity(substs.len()); + for (arg, v) in std::iter::zip(substs, self.tcx.variances_of(def_id)) { + mapped_substs.push(match (arg.unpack(), v) { + // Skip uncaptured opaque substs + (ty::GenericArgKind::Lifetime(_), ty::Bivariant) => arg, + _ => arg.try_fold_with(self)?, + }); + } + Ok(self.tcx.mk_opaque(def_id, self.tcx.mk_substs(&mapped_substs))) + } else { + t.try_super_fold_with(self) + } + } + + fn try_fold_region( + &mut self, + region: ty::Region<'tcx>, + ) -> Result<ty::Region<'tcx>, Self::Error> { + match region.kind() { + // Remap all free regions, which correspond to late-bound regions in the function. + ty::ReFree(_) => {} + // Remap early-bound regions as long as they don't come from the `impl` itself, + // in which case we don't really need to renumber them. + ty::ReEarlyBound(ebr) if self.tcx.parent(ebr.def_id) != self.impl_def_id => {} + _ => return Ok(region), + } + + let e = if let Some(region) = self.map.get(®ion) { + if let ty::ReEarlyBound(e) = region.kind() { e } else { bug!() } + } else { + let guar = match region.kind() { + ty::ReEarlyBound(ty::EarlyBoundRegion { def_id, .. }) + | ty::ReFree(ty::FreeRegion { + bound_region: ty::BoundRegionKind::BrNamed(def_id, _), + .. + }) => { + let return_span = if let ty::Alias(ty::Opaque, opaque_ty) = self.ty.kind() { + self.tcx.def_span(opaque_ty.def_id) + } else { + self.return_span + }; + self.tcx + .sess + .struct_span_err( + return_span, + "return type captures more lifetimes than trait definition", + ) + .span_label(self.tcx.def_span(def_id), "this lifetime was captured") + .span_note( + self.tcx.def_span(self.def_id), + "hidden type must only reference lifetimes captured by this impl trait", + ) + .note(format!("hidden type inferred to be `{}`", self.ty)) + .emit() + } + _ => self.tcx.sess.delay_span_bug(DUMMY_SP, "should've been able to remap region"), + }; + return Err(guar); + }; + + Ok(ty::Region::new_early_bound( + self.tcx, + ty::EarlyBoundRegion { + def_id: e.def_id, + name: e.name, + index: (e.index as usize - self.num_trait_substs + self.num_impl_substs) as u32, + }, + )) + } +} + fn report_trait_method_mismatch<'tcx>( infcx: &InferCtxt<'tcx>, mut cause: ObligationCause<'tcx>, diff --git a/tests/ui/impl-trait/in-trait/method-signature-matches.lt.stderr b/tests/ui/impl-trait/in-trait/method-signature-matches.lt.stderr index f604ada6ac7..239c4b35c72 100644 --- a/tests/ui/impl-trait/in-trait/method-signature-matches.lt.stderr +++ b/tests/ui/impl-trait/in-trait/method-signature-matches.lt.stderr @@ -5,7 +5,7 @@ LL | fn early<'late, T>(_: &'late ()) {} | - ^^^^^^^^^ | | | | | expected type parameter `T`, found `()` - | | help: change the parameter type to match the trait: `&'early T` + | | help: change the parameter type to match the trait: `&T` | this type parameter | note: type in trait @@ -13,8 +13,8 @@ note: type in trait | LL | fn early<'early, T>(x: &'early T) -> impl Sized; | ^^^^^^^^^ - = note: expected signature `fn(&'early T)` - found signature `fn(&())` + = note: expected signature `fn(&T)` + found signature `fn(&'late ())` error: aborting due to previous error diff --git a/tests/ui/impl-trait/in-trait/signature-mismatch.current.stderr b/tests/ui/impl-trait/in-trait/signature-mismatch.current.stderr index eba270af7f0..8c9dd403174 100644 --- a/tests/ui/impl-trait/in-trait/signature-mismatch.current.stderr +++ b/tests/ui/impl-trait/in-trait/signature-mismatch.current.stderr @@ -1,16 +1,61 @@ -error: `impl` item signature doesn't match `trait` item signature - --> $DIR/signature-mismatch.rs:17:5 +error: return type captures more lifetimes than trait definition + --> $DIR/signature-mismatch.rs:36:47 + | +LL | fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a { + | -- this lifetime was captured ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: hidden type must only reference lifetimes captured by this impl trait + --> $DIR/signature-mismatch.rs:17:40 | LL | fn async_fn(&self, buff: &[u8]) -> impl Future<Output = Vec<u8>>; - | ----------------------------------------------------------------- expected `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '3` + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + = note: hidden type inferred to be `impl Future<Output = Vec<u8>> + 'a` + +error: return type captures more lifetimes than trait definition + --> $DIR/signature-mismatch.rs:41:57 + | +LL | fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a { + | -- this lifetime was captured ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: hidden type must only reference lifetimes captured by this impl trait + --> $DIR/signature-mismatch.rs:18:57 + | +LL | fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>>; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + = note: hidden type inferred to be `impl Future<Output = Vec<u8>> + 'a` + +error: return type captures more lifetimes than trait definition + --> $DIR/signature-mismatch.rs:49:10 + | +LL | fn async_fn_multiple<'a, 'b>( + | -- this lifetime was captured ... -LL | fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a { - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '2` +LL | ) -> impl Future<Output = Vec<u8>> + Captures2<'a, 'b> { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: hidden type must only reference lifetimes captured by this impl trait + --> $DIR/signature-mismatch.rs:20:12 + | +LL | -> impl Future<Output = Vec<u8>> + Captures<'a>; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + = note: hidden type inferred to be `impl Future<Output = Vec<u8>> + Captures2<'a, 'b>` + +error[E0309]: the parameter type `T` may not live long enough + --> $DIR/signature-mismatch.rs:58:10 + | +LL | ) -> impl Future<Output = Vec<u8>> { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `impl Future<Output = Vec<u8>>` will meet its required lifetime bounds... + | +note: ...that is required by this bound + --> $DIR/signature-mismatch.rs:25:42 + | +LL | ) -> impl Future<Output = Vec<u8>> + 'a; + | ^^ +help: consider adding an explicit lifetime bound... | - = note: expected signature `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '3` - found signature `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '2` - = help: the lifetime requirements from the `impl` do not correspond to the requirements in the `trait` - = help: verify the lifetime relationships in the `trait` and `impl` between the `self` argument, the other inputs and its output +LL | fn async_fn_reduce_outlive<'a, 'b, T: 'a>( + | ++++ -error: aborting due to previous error +error: aborting due to 4 previous errors +For more information about this error, try `rustc --explain E0309`. diff --git a/tests/ui/impl-trait/in-trait/signature-mismatch.next.stderr b/tests/ui/impl-trait/in-trait/signature-mismatch.next.stderr index eba270af7f0..8c9dd403174 100644 --- a/tests/ui/impl-trait/in-trait/signature-mismatch.next.stderr +++ b/tests/ui/impl-trait/in-trait/signature-mismatch.next.stderr @@ -1,16 +1,61 @@ -error: `impl` item signature doesn't match `trait` item signature - --> $DIR/signature-mismatch.rs:17:5 +error: return type captures more lifetimes than trait definition + --> $DIR/signature-mismatch.rs:36:47 + | +LL | fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a { + | -- this lifetime was captured ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: hidden type must only reference lifetimes captured by this impl trait + --> $DIR/signature-mismatch.rs:17:40 | LL | fn async_fn(&self, buff: &[u8]) -> impl Future<Output = Vec<u8>>; - | ----------------------------------------------------------------- expected `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '3` + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + = note: hidden type inferred to be `impl Future<Output = Vec<u8>> + 'a` + +error: return type captures more lifetimes than trait definition + --> $DIR/signature-mismatch.rs:41:57 + | +LL | fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a { + | -- this lifetime was captured ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: hidden type must only reference lifetimes captured by this impl trait + --> $DIR/signature-mismatch.rs:18:57 + | +LL | fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>>; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + = note: hidden type inferred to be `impl Future<Output = Vec<u8>> + 'a` + +error: return type captures more lifetimes than trait definition + --> $DIR/signature-mismatch.rs:49:10 + | +LL | fn async_fn_multiple<'a, 'b>( + | -- this lifetime was captured ... -LL | fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a { - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ found `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '2` +LL | ) -> impl Future<Output = Vec<u8>> + Captures2<'a, 'b> { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + | +note: hidden type must only reference lifetimes captured by this impl trait + --> $DIR/signature-mismatch.rs:20:12 + | +LL | -> impl Future<Output = Vec<u8>> + Captures<'a>; + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + = note: hidden type inferred to be `impl Future<Output = Vec<u8>> + Captures2<'a, 'b>` + +error[E0309]: the parameter type `T` may not live long enough + --> $DIR/signature-mismatch.rs:58:10 + | +LL | ) -> impl Future<Output = Vec<u8>> { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...so that the type `impl Future<Output = Vec<u8>>` will meet its required lifetime bounds... + | +note: ...that is required by this bound + --> $DIR/signature-mismatch.rs:25:42 + | +LL | ) -> impl Future<Output = Vec<u8>> + 'a; + | ^^ +help: consider adding an explicit lifetime bound... | - = note: expected signature `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '3` - found signature `fn(&'1 Struct, &'2 [u8]) -> impl Future<Output = Vec<u8>> + '2` - = help: the lifetime requirements from the `impl` do not correspond to the requirements in the `trait` - = help: verify the lifetime relationships in the `trait` and `impl` between the `self` argument, the other inputs and its output +LL | fn async_fn_reduce_outlive<'a, 'b, T: 'a>( + | ++++ -error: aborting due to previous error +error: aborting due to 4 previous errors +For more information about this error, try `rustc --explain E0309`. diff --git a/tests/ui/impl-trait/in-trait/signature-mismatch.rs b/tests/ui/impl-trait/in-trait/signature-mismatch.rs index 38c902a97a9..23dd71acecb 100644 --- a/tests/ui/impl-trait/in-trait/signature-mismatch.rs +++ b/tests/ui/impl-trait/in-trait/signature-mismatch.rs @@ -7,17 +7,70 @@ use std::future::Future; +trait Captures<'a> {} +impl<T> Captures<'_> for T {} + +trait Captures2<'a, 'b> {} +impl<T> Captures2<'_, '_> for T {} + pub trait AsyncTrait { fn async_fn(&self, buff: &[u8]) -> impl Future<Output = Vec<u8>>; + fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>>; + fn async_fn_multiple<'a>(&'a self, buff: &[u8]) + -> impl Future<Output = Vec<u8>> + Captures<'a>; + fn async_fn_reduce_outlive<'a, T>( + &'a self, + buff: &[u8], + t: T, + ) -> impl Future<Output = Vec<u8>> + 'a; + fn async_fn_reduce<'a, T>( + &'a self, + buff: &[u8], + t: T, + ) -> impl Future<Output = Vec<u8>> + Captures<'a>; } pub struct Struct; impl AsyncTrait for Struct { fn async_fn<'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a { - //~^ ERROR `impl` item signature doesn't match `trait` item signature + //~^ ERROR return type captures more lifetimes than trait definition + async move { buff.to_vec() } + } + + fn async_fn_early<'a: 'a>(&self, buff: &'a [u8]) -> impl Future<Output = Vec<u8>> + 'a { + //~^ ERROR return type captures more lifetimes than trait definition + async move { buff.to_vec() } + } + + fn async_fn_multiple<'a, 'b>( + &'a self, + buff: &'b [u8], + ) -> impl Future<Output = Vec<u8>> + Captures2<'a, 'b> { + //~^ ERROR return type captures more lifetimes than trait definition async move { buff.to_vec() } } + + fn async_fn_reduce_outlive<'a, 'b, T>( + &'a self, + buff: &'b [u8], + t: T, + ) -> impl Future<Output = Vec<u8>> { + //~^ ERROR the parameter type `T` may not live long enough + async move { + let _t = t; + vec![] + } + } + + // OK: We remove the `Captures<'a>`, providing a guarantee that we don't capture `'a`, + // but we still fulfill the `Captures<'a>` trait bound. + fn async_fn_reduce<'a, 'b, T>(&'a self, buff: &'b [u8], t: T) -> impl Future<Output = Vec<u8>> { + async move { + let _t = t; + vec![] + } + } } fn main() {} |