diff options
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/wfcheck.rs | 105 | ||||
| -rw-r--r-- | tests/ui/impl-trait/in-trait/wf-bounds.current.stderr | 20 | ||||
| -rw-r--r-- | tests/ui/impl-trait/in-trait/wf-bounds.next.stderr | 20 | ||||
| -rw-r--r-- | tests/ui/impl-trait/in-trait/wf-bounds.rs | 7 |
4 files changed, 108 insertions, 44 deletions
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs index 737532b98a4..491bd04f346 100644 --- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs +++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs @@ -1544,42 +1544,81 @@ fn check_return_position_impl_trait_in_trait_bounds<'tcx>( span: Span, ) { let tcx = wfcx.tcx(); - if let Some(assoc_item) = tcx.opt_associated_item(fn_def_id.to_def_id()) - && assoc_item.container == ty::AssocItemContainer::TraitContainer - { - // FIXME(-Zlower-impl-trait-in-trait-to-assoc-ty): Even with the new lowering - // strategy, we can't just call `check_associated_item` on the new RPITITs, - // because tests like `tests/ui/async-await/in-trait/implied-bounds.rs` will fail. - // That's because we need to check that the bounds of the RPITIT hold using - // the special substs that we create during opaque type lowering, otherwise we're - // getting a bunch of early bound and free regions mixed up... Haven't looked too - // deep into this, though. - for arg in fn_output.walk() { - if let ty::GenericArgKind::Type(ty) = arg.unpack() - // RPITITs are always eagerly normalized into opaques, so always look for an - // opaque here. - && let ty::Alias(ty::Opaque, opaque_ty) = ty.kind() - && let Some(opaque_def_id) = opaque_ty.def_id.as_local() - && let opaque = tcx.hir().expect_item(opaque_def_id).expect_opaque_ty() - && let hir::OpaqueTyOrigin::FnReturn(source) | hir::OpaqueTyOrigin::AsyncFn(source) = opaque.origin - && source == fn_def_id + let Some(assoc_item) = tcx.opt_associated_item(fn_def_id.to_def_id()) else { + return; + }; + if assoc_item.container != ty::AssocItemContainer::TraitContainer { + return; + } + fn_output.visit_with(&mut ImplTraitInTraitFinder { + wfcx, + fn_def_id, + depth: ty::INNERMOST, + seen: FxHashSet::default(), + }); +} + +// FIXME(-Zlower-impl-trait-in-trait-to-assoc-ty): Even with the new lowering +// strategy, we can't just call `check_associated_item` on the new RPITITs, +// because tests like `tests/ui/async-await/in-trait/implied-bounds.rs` will fail. +// That's because we need to check that the bounds of the RPITIT hold using +// the special substs that we create during opaque type lowering, otherwise we're +// getting a bunch of early bound and free regions mixed up... Haven't looked too +// deep into this, though. +struct ImplTraitInTraitFinder<'a, 'tcx> { + wfcx: &'a WfCheckingCtxt<'a, 'tcx>, + fn_def_id: LocalDefId, + depth: ty::DebruijnIndex, + seen: FxHashSet<DefId>, +} +impl<'tcx> TypeVisitor<TyCtxt<'tcx>> for ImplTraitInTraitFinder<'_, 'tcx> { + type BreakTy = !; + + fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<!> { + let tcx = self.wfcx.tcx(); + if let ty::Alias(ty::Opaque, unshifted_opaque_ty) = *ty.kind() + && self.seen.insert(unshifted_opaque_ty.def_id) + && let Some(opaque_def_id) = unshifted_opaque_ty.def_id.as_local() + && let opaque = tcx.hir().expect_item(opaque_def_id).expect_opaque_ty() + && let hir::OpaqueTyOrigin::FnReturn(source) | hir::OpaqueTyOrigin::AsyncFn(source) = opaque.origin + && source == self.fn_def_id + { + let opaque_ty = tcx.fold_regions(unshifted_opaque_ty, |re, depth| { + if let ty::ReLateBound(index, bv) = re.kind() { + if depth != ty::INNERMOST { + return tcx.mk_re_error_with_message( + DUMMY_SP, + "we shouldn't walk non-predicate binders with `impl Trait`...", + ); + } + tcx.mk_re_late_bound(index.shifted_out_to_binder(self.depth), bv) + } else { + re + } + }); + for (bound, bound_span) in tcx + .bound_explicit_item_bounds(opaque_ty.def_id) + .subst_iter_copied(tcx, opaque_ty.substs) { - let span = tcx.def_span(opaque_ty.def_id); - let bounds = wfcx.tcx().explicit_item_bounds(opaque_ty.def_id); - let wf_obligations = bounds.iter().flat_map(|&(bound, bound_span)| { - let bound = ty::EarlyBinder(bound).subst(tcx, opaque_ty.substs); - let normalized_bound = wfcx.normalize(span, None, bound); - traits::wf::predicate_obligations( - wfcx.infcx, - wfcx.param_env, - wfcx.body_def_id, - normalized_bound, - bound_span, - ) - }); - wfcx.register_obligations(wf_obligations); + let bound = self.wfcx.normalize(bound_span, None, bound); + self.wfcx.register_obligations(traits::wf::predicate_obligations( + self.wfcx.infcx, + self.wfcx.param_env, + self.wfcx.body_def_id, + bound, + bound_span, + )); + // Set the debruijn index back to innermost here, since we already eagerly + // shifted the substs that we use to generate these bounds. This is unfortunately + // subtly different behavior than the `ImplTraitInTraitFinder` we use in `param_env`, + // but that function doesn't actually need to normalize the bound it's visiting + // (whereas we have to do so here)... + let old_depth = std::mem::replace(&mut self.depth, ty::INNERMOST); + bound.visit_with(self); + self.depth = old_depth; } } + ty.super_visit_with(self) } } diff --git a/tests/ui/impl-trait/in-trait/wf-bounds.current.stderr b/tests/ui/impl-trait/in-trait/wf-bounds.current.stderr index 8392f26e7c8..1a70716123c 100644 --- a/tests/ui/impl-trait/in-trait/wf-bounds.current.stderr +++ b/tests/ui/impl-trait/in-trait/wf-bounds.current.stderr @@ -1,5 +1,5 @@ error[E0277]: the size for values of type `[u8]` cannot be known at compilation time - --> $DIR/wf-bounds.rs:11:22 + --> $DIR/wf-bounds.rs:13:22 | LL | fn nya() -> impl Wf<Vec<[u8]>>; | ^^^^^^^^^^^^^ doesn't have a size known at compile-time @@ -9,7 +9,7 @@ note: required by a bound in `Vec` --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL error[E0277]: the size for values of type `[u8]` cannot be known at compilation time - --> $DIR/wf-bounds.rs:14:23 + --> $DIR/wf-bounds.rs:16:23 | LL | fn nya2() -> impl Wf<[u8]>; | ^^^^^^^^ doesn't have a size known at compile-time @@ -18,13 +18,23 @@ LL | fn nya2() -> impl Wf<[u8]>; note: required by a bound in `Wf` --> $DIR/wf-bounds.rs:8:10 | -LL | trait Wf<T> {} +LL | trait Wf<T> { | ^ required by this bound in `Wf` help: consider relaxing the implicit `Sized` restriction | -LL | trait Wf<T: ?Sized> {} +LL | trait Wf<T: ?Sized> { | ++++++++ -error: aborting due to 2 previous errors +error[E0277]: the size for values of type `[u8]` cannot be known at compilation time + --> $DIR/wf-bounds.rs:19:44 + | +LL | fn nya3() -> impl Wf<(), Output = impl Wf<Vec<[u8]>>>; + | ^^^^^^^^^^^^^ doesn't have a size known at compile-time + | + = help: the trait `Sized` is not implemented for `[u8]` +note: required by a bound in `Vec` + --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL + +error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0277`. diff --git a/tests/ui/impl-trait/in-trait/wf-bounds.next.stderr b/tests/ui/impl-trait/in-trait/wf-bounds.next.stderr index 8392f26e7c8..1a70716123c 100644 --- a/tests/ui/impl-trait/in-trait/wf-bounds.next.stderr +++ b/tests/ui/impl-trait/in-trait/wf-bounds.next.stderr @@ -1,5 +1,5 @@ error[E0277]: the size for values of type `[u8]` cannot be known at compilation time - --> $DIR/wf-bounds.rs:11:22 + --> $DIR/wf-bounds.rs:13:22 | LL | fn nya() -> impl Wf<Vec<[u8]>>; | ^^^^^^^^^^^^^ doesn't have a size known at compile-time @@ -9,7 +9,7 @@ note: required by a bound in `Vec` --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL error[E0277]: the size for values of type `[u8]` cannot be known at compilation time - --> $DIR/wf-bounds.rs:14:23 + --> $DIR/wf-bounds.rs:16:23 | LL | fn nya2() -> impl Wf<[u8]>; | ^^^^^^^^ doesn't have a size known at compile-time @@ -18,13 +18,23 @@ LL | fn nya2() -> impl Wf<[u8]>; note: required by a bound in `Wf` --> $DIR/wf-bounds.rs:8:10 | -LL | trait Wf<T> {} +LL | trait Wf<T> { | ^ required by this bound in `Wf` help: consider relaxing the implicit `Sized` restriction | -LL | trait Wf<T: ?Sized> {} +LL | trait Wf<T: ?Sized> { | ++++++++ -error: aborting due to 2 previous errors +error[E0277]: the size for values of type `[u8]` cannot be known at compilation time + --> $DIR/wf-bounds.rs:19:44 + | +LL | fn nya3() -> impl Wf<(), Output = impl Wf<Vec<[u8]>>>; + | ^^^^^^^^^^^^^ doesn't have a size known at compile-time + | + = help: the trait `Sized` is not implemented for `[u8]` +note: required by a bound in `Vec` + --> $SRC_DIR/alloc/src/vec/mod.rs:LL:COL + +error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0277`. diff --git a/tests/ui/impl-trait/in-trait/wf-bounds.rs b/tests/ui/impl-trait/in-trait/wf-bounds.rs index 39f41275315..1c9590bd853 100644 --- a/tests/ui/impl-trait/in-trait/wf-bounds.rs +++ b/tests/ui/impl-trait/in-trait/wf-bounds.rs @@ -5,7 +5,9 @@ #![feature(return_position_impl_trait_in_trait)] #![allow(incomplete_features)] -trait Wf<T> {} +trait Wf<T> { + type Output; +} trait Uwu { fn nya() -> impl Wf<Vec<[u8]>>; @@ -13,6 +15,9 @@ trait Uwu { fn nya2() -> impl Wf<[u8]>; //~^ ERROR the size for values of type `[u8]` cannot be known at compilation time + + fn nya3() -> impl Wf<(), Output = impl Wf<Vec<[u8]>>>; + //~^ ERROR the size for values of type `[u8]` cannot be known at compilation time } fn main() {} |