From 15dff274d07621283b38e4ca0008f7e6145c2519 Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Sun, 24 Nov 2024 22:39:19 +0000 Subject: [PATCH 1/2] Actually use placeholder regions for trait method late bound regions in collect_return_position_impl_trait_in_trait_tys --- .../src/check/compare_impl_item.rs | 12 ++++---- .../in-trait/do-not-imply-from-trait-impl.rs | 30 +++++++++++++++++++ .../do-not-imply-from-trait-impl.stderr | 22 ++++++++++++++ .../method-signature-matches.lt.stderr | 8 ++--- ...rpitit-hidden-types-self-implied-wf.stderr | 4 +-- .../signature-mismatch.failure.stderr | 15 +++++----- .../impl-trait/in-trait/signature-mismatch.rs | 2 +- .../rpitit-impl-captures-too-much.stderr | 7 +++-- 8 files changed, 77 insertions(+), 23 deletions(-) create mode 100644 tests/ui/impl-trait/in-trait/do-not-imply-from-trait-impl.rs create mode 100644 tests/ui/impl-trait/in-trait/do-not-imply-from-trait-impl.stderr 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 f86ca95a954b2..dd10625589010 100644 --- a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs +++ b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs @@ -523,8 +523,9 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( let impl_sig = ocx.normalize( &misc_cause, param_env, - tcx.liberate_late_bound_regions( - impl_m.def_id, + infcx.instantiate_binder_with_fresh_vars( + return_span, + infer::HigherRankedType, tcx.fn_sig(impl_m.def_id).instantiate_identity(), ), ); @@ -536,10 +537,9 @@ 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 = infcx - .instantiate_binder_with_fresh_vars( - return_span, - infer::HigherRankedType, + let unnormalized_trait_sig = tcx + .liberate_late_bound_regions( + impl_m.def_id, tcx.fn_sig(trait_m.def_id).instantiate(tcx, trait_to_impl_args), ) .fold_with(&mut collector); diff --git a/tests/ui/impl-trait/in-trait/do-not-imply-from-trait-impl.rs b/tests/ui/impl-trait/in-trait/do-not-imply-from-trait-impl.rs new file mode 100644 index 0000000000000..30ca3d271b815 --- /dev/null +++ b/tests/ui/impl-trait/in-trait/do-not-imply-from-trait-impl.rs @@ -0,0 +1,30 @@ +// Make sure that we don't accidentally collect an RPITIT hidden type that does not +// hold for all instantiations of the trait signature. + +trait MkStatic { + fn mk_static(self) -> &'static str; +} + +impl MkStatic for &'static str { + fn mk_static(self) -> &'static str { self } +} + +trait Foo { + fn foo<'a: 'static, 'late>(&'late self) -> impl MkStatic; +} + +impl Foo for str { + fn foo<'a: 'static>(&'a self) -> impl MkStatic + 'static { + //~^ ERROR method not compatible with trait + self + } +} + +fn call_foo(t: &T) -> &'static str { + t.foo().mk_static() +} + +fn main() { + let s = call_foo(String::from("hello, world").as_str()); + println!("> {s}"); +} diff --git a/tests/ui/impl-trait/in-trait/do-not-imply-from-trait-impl.stderr b/tests/ui/impl-trait/in-trait/do-not-imply-from-trait-impl.stderr new file mode 100644 index 0000000000000..95d8699e19ff1 --- /dev/null +++ b/tests/ui/impl-trait/in-trait/do-not-imply-from-trait-impl.stderr @@ -0,0 +1,22 @@ +error[E0308]: method not compatible with trait + --> $DIR/do-not-imply-from-trait-impl.rs:17:38 + | +LL | fn foo<'a: 'static>(&'a self) -> impl MkStatic + 'static { + | ^^^^^^^^^^^^^^^^^^^^^^^ lifetime mismatch + | + = note: expected signature `fn(&'late _) -> _` + found signature `fn(&'a _) -> _` +note: the lifetime `'late` as defined here... + --> $DIR/do-not-imply-from-trait-impl.rs:13:25 + | +LL | fn foo<'a: 'static, 'late>(&'late self) -> impl MkStatic; + | ^^^^^ +note: ...does not necessarily outlive the lifetime `'a` as defined here + --> $DIR/do-not-imply-from-trait-impl.rs:17:12 + | +LL | fn foo<'a: 'static>(&'a self) -> impl MkStatic + 'static { + | ^^ + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0308`. 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 6f6b787b6fe1b..a23879eb6c376 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 @@ -11,12 +11,12 @@ note: type in trait | LL | fn early<'early, T>(x: &'early T) -> impl Sized; | ^^^^^^^^^ - = note: expected signature `fn(&T)` - found signature `fn(&'late ())` + = note: expected signature `fn(&'early T)` + found signature `fn(&())` help: change the parameter type to match the trait | -LL | fn early<'late, T>(_: &T) {} - | ~~ +LL | fn early<'late, T>(_: &'early T) {} + | ~~~~~~~~~ error: aborting due to 1 previous error diff --git a/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.stderr b/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.stderr index 3430055dab171..4c10422f985f1 100644 --- a/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.stderr +++ b/tests/ui/impl-trait/in-trait/rpitit-hidden-types-self-implied-wf.stderr @@ -6,9 +6,9 @@ LL | fn extend(s: &str) -> (Option<&'static &'_ ()>, &'static str) { | = note: the pointer is valid for the static lifetime note: but the referenced data is only valid for the anonymous lifetime defined here - --> $DIR/rpitit-hidden-types-self-implied-wf.rs:6:18 + --> $DIR/rpitit-hidden-types-self-implied-wf.rs:2:18 | -LL | fn extend(s: &str) -> (Option<&'static &'_ ()>, &'static str) { +LL | fn extend(_: &str) -> (impl Sized + '_, &'static str); | ^^^^ error: aborting due to 1 previous error diff --git a/tests/ui/impl-trait/in-trait/signature-mismatch.failure.stderr b/tests/ui/impl-trait/in-trait/signature-mismatch.failure.stderr index 56b83cbca77ac..b27d7870955ed 100644 --- a/tests/ui/impl-trait/in-trait/signature-mismatch.failure.stderr +++ b/tests/ui/impl-trait/in-trait/signature-mismatch.failure.stderr @@ -1,14 +1,15 @@ -error[E0623]: lifetime mismatch +error[E0477]: the type `impl Future>` does not fulfill the required lifetime --> $DIR/signature-mismatch.rs:77:10 | -LL | &'a self, - | -------- this parameter and the return type are declared with different lifetimes... -... LL | ) -> impl Future> { | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - | | - | ...but data from `buff` is returned here + | +note: type must outlive the lifetime `'a` as defined here as required by this binding + --> $DIR/signature-mismatch.rs:73:32 + | +LL | fn async_fn_reduce_outlive<'a, 'b, T>( + | ^^ error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0623`. +For more information about this error, try `rustc --explain E0477`. diff --git a/tests/ui/impl-trait/in-trait/signature-mismatch.rs b/tests/ui/impl-trait/in-trait/signature-mismatch.rs index 55b9a0de5ff02..a9885c6a2986b 100644 --- a/tests/ui/impl-trait/in-trait/signature-mismatch.rs +++ b/tests/ui/impl-trait/in-trait/signature-mismatch.rs @@ -75,7 +75,7 @@ impl AsyncTrait for Struct { buff: &'b [u8], t: T, ) -> impl Future> { - //[failure]~^ ERROR lifetime mismatch + //[failure]~^ ERROR the type `impl Future>` does not fulfill the required lifetime async move { let _t = t; vec![] diff --git a/tests/ui/impl-trait/precise-capturing/rpitit-impl-captures-too-much.stderr b/tests/ui/impl-trait/precise-capturing/rpitit-impl-captures-too-much.stderr index e1856b929106e..360f0d7e7f37f 100644 --- a/tests/ui/impl-trait/precise-capturing/rpitit-impl-captures-too-much.stderr +++ b/tests/ui/impl-trait/precise-capturing/rpitit-impl-captures-too-much.stderr @@ -1,10 +1,11 @@ error: return type captures more lifetimes than trait definition --> $DIR/rpitit-impl-captures-too-much.rs:10:39 | +LL | fn hello(self_: Invariant<'_>) -> impl Sized + use; + | -- this lifetime was captured +... LL | fn hello(self_: Invariant<'_>) -> impl Sized + use<'_> {} - | -- ^^^^^^^^^^^^^^^^^^^^ - | | - | this lifetime was captured + | ^^^^^^^^^^^^^^^^^^^^ | note: hidden type must only reference lifetimes captured by this impl trait --> $DIR/rpitit-impl-captures-too-much.rs:6:39 From 871cfc9dff54ad64929e75c19c9dc8cbd5e300e2 Mon Sep 17 00:00:00 2001 From: Michael Goulet Date: Sun, 24 Nov 2024 23:08:19 +0000 Subject: [PATCH 2/2] Further simplifications --- .../src/check/compare_impl_item.rs | 36 ++++++++----------- 1 file changed, 15 insertions(+), 21 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 dd10625589010..1ae71d807cd53 100644 --- a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs +++ b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs @@ -702,8 +702,8 @@ pub(super) fn collect_return_position_impl_trait_in_trait_tys<'tcx>( let mut remapped_types = DefIdMap::default(); for (def_id, (ty, args)) in collected_types { - match infcx.fully_resolve((ty, args)) { - Ok((ty, args)) => { + match infcx.fully_resolve(ty) { + Ok(ty) => { // `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. @@ -883,33 +883,27 @@ impl<'tcx> ty::FallibleTypeFolder> for RemapHiddenTyRegions<'tcx> { self.tcx } - fn try_fold_ty(&mut self, t: Ty<'tcx>) -> Result, Self::Error> { - if let ty::Alias(ty::Opaque, ty::AliasTy { args, def_id, .. }) = *t.kind() { - let mut mapped_args = Vec::with_capacity(args.len()); - for (arg, v) in std::iter::zip(args, self.tcx.variances_of(def_id)) { - mapped_args.push(match (arg.unpack(), v) { - // Skip uncaptured opaque args - (ty::GenericArgKind::Lifetime(_), ty::Bivariant) => arg, - _ => arg.try_fold_with(self)?, - }); - } - Ok(Ty::new_opaque(self.tcx, def_id, self.tcx.mk_args(&mapped_args))) - } else { - t.try_super_fold_with(self) - } - } - fn try_fold_region( &mut self, region: ty::Region<'tcx>, ) -> Result, Self::Error> { match region.kind() { - // Remap late-bound regions from the function. + // Never remap bound regions or `'static` + ty::ReBound(..) | ty::ReStatic | ty::ReError(_) => return Ok(region), + // We always remap liberated late-bound regions from the function. ty::ReLateParam(_) => {} // 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::ReEarlyParam(ebr) if ebr.index as usize >= self.num_impl_args => {} - _ => return Ok(region), + ty::ReEarlyParam(ebr) => { + if ebr.index as usize >= self.num_impl_args { + // Remap + } else { + return Ok(region); + } + } + ty::ReVar(_) | ty::RePlaceholder(_) | ty::ReErased => unreachable!( + "should not have leaked vars or placeholders into hidden type of RPITIT" + ), } let e = if let Some(id_region) = self.map.get(®ion) {