diff --git a/compiler/rustc_borrowck/src/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs index 54c516c960c1f..599f7dd18c3ea 100644 --- a/compiler/rustc_borrowck/src/region_infer/mod.rs +++ b/compiler/rustc_borrowck/src/region_infer/mod.rs @@ -95,9 +95,11 @@ pub struct RegionInferenceContext<'tcx> { /// visible from this index. scc_universes: IndexVec, - /// Contains a "representative" from each SCC. This will be the - /// minimal RegionVid belonging to that universe. It is used as a - /// kind of hacky way to manage checking outlives relationships, + /// Contains the "representative" region of each SCC. + /// It is defined as the one with the minimal RegionVid, favoring + /// free regions, then placeholders, then existential regions. + /// + /// It is a hacky way to manage checking regions for equality, /// since we can 'canonicalize' each region to the representative /// of its SCC and be sure that -- if they have the same repr -- /// they *must* be equal (though not having the same repr does not @@ -481,8 +483,7 @@ impl<'tcx> RegionInferenceContext<'tcx> { scc_universes } - /// For each SCC, we compute a unique `RegionVid` (in fact, the - /// minimal one that belongs to the SCC). See + /// For each SCC, we compute a unique `RegionVid`. See the /// `scc_representatives` field of `RegionInferenceContext` for /// more details. fn compute_scc_representatives( @@ -490,13 +491,20 @@ impl<'tcx> RegionInferenceContext<'tcx> { definitions: &IndexSlice>, ) -> IndexVec { let num_sccs = constraints_scc.num_sccs(); - let next_region_vid = definitions.next_index(); - let mut scc_representatives = IndexVec::from_elem_n(next_region_vid, num_sccs); - - for region_vid in definitions.indices() { - let scc = constraints_scc.scc(region_vid); - let prev_min = scc_representatives[scc]; - scc_representatives[scc] = region_vid.min(prev_min); + let mut scc_representatives = IndexVec::from_elem_n(RegionVid::MAX, num_sccs); + + // Iterate over all RegionVids *in-order* and pick the least RegionVid as the + // representative of its SCC. This naturally prefers free regions over others. + for (vid, def) in definitions.iter_enumerated() { + let repr = &mut scc_representatives[constraints_scc.scc(vid)]; + if *repr == ty::RegionVid::MAX { + *repr = vid; + } else if matches!(def.origin, NllRegionVariableOrigin::Placeholder(_)) + && matches!(definitions[*repr].origin, NllRegionVariableOrigin::Existential { .. }) + { + // Pick placeholders over existentials even if they have a greater RegionVid. + *repr = vid; + } } scc_representatives diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs index d5875a226fe02..63b8044581747 100644 --- a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs +++ b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs @@ -1,15 +1,14 @@ -use rustc_data_structures::fx::{FxIndexMap, FxIndexSet}; +use rustc_data_structures::fx::FxIndexMap; use rustc_errors::ErrorGuaranteed; use rustc_hir::def::DefKind; use rustc_hir::def_id::LocalDefId; use rustc_hir::OpaqueTyOrigin; -use rustc_infer::infer::InferCtxt; use rustc_infer::infer::TyCtxtInferExt as _; +use rustc_infer::infer::{InferCtxt, NllRegionVariableOrigin}; use rustc_infer::traits::{Obligation, ObligationCause}; use rustc_macros::extension; use rustc_middle::traits::DefiningAnchor; use rustc_middle::ty::visit::TypeVisitableExt; -use rustc_middle::ty::RegionVid; use rustc_middle::ty::{self, OpaqueHiddenType, OpaqueTypeKey, Ty, TyCtxt, TypeFoldable}; use rustc_middle::ty::{GenericArgKind, GenericArgs}; use rustc_span::Span; @@ -18,76 +17,19 @@ use rustc_trait_selection::traits::ObligationCtxt; use crate::session_diagnostics::LifetimeMismatchOpaqueParam; use crate::session_diagnostics::NonGenericOpaqueTypeParam; +use crate::universal_regions::RegionClassification; use super::RegionInferenceContext; impl<'tcx> RegionInferenceContext<'tcx> { - fn universal_name(&self, vid: ty::RegionVid) -> Option> { - let scc = self.constraint_sccs.scc(vid); - self.scc_values - .universal_regions_outlived_by(scc) - .find_map(|lb| self.eval_equal(vid, lb).then_some(self.definitions[lb].external_name?)) - } - - fn generic_arg_to_region(&self, arg: ty::GenericArg<'tcx>) -> Option { - let region = arg.as_region()?; - - if let ty::RePlaceholder(..) = region.kind() { - None - } else { - Some(self.to_region_vid(region)) - } - } - - /// Check that all opaque types have the same region parameters if they have the same - /// non-region parameters. This is necessary because within the new solver we perform various query operations - /// modulo regions, and thus could unsoundly select some impls that don't hold. - fn check_unique( - &self, - infcx: &InferCtxt<'tcx>, - opaque_ty_decls: &FxIndexMap, OpaqueHiddenType<'tcx>>, - ) { - for (i, (a, a_ty)) in opaque_ty_decls.iter().enumerate() { - for (b, b_ty) in opaque_ty_decls.iter().skip(i + 1) { - if a.def_id != b.def_id { - continue; - } - // Non-lifetime params differ -> ok - if infcx.tcx.erase_regions(a.args) != infcx.tcx.erase_regions(b.args) { - continue; - } - trace!(?a, ?b); - for (a, b) in a.args.iter().zip(b.args) { - trace!(?a, ?b); - let Some(r1) = self.generic_arg_to_region(a) else { - continue; - }; - let Some(r2) = self.generic_arg_to_region(b) else { - continue; - }; - if self.eval_equal(r1, r2) { - continue; - } - - infcx.dcx().emit_err(LifetimeMismatchOpaqueParam { - arg: self.universal_name(r1).unwrap().into(), - prev: self.universal_name(r2).unwrap().into(), - span: a_ty.span, - prev_span: b_ty.span, - }); - } - } - } - } - /// Resolve any opaque types that were encountered while borrow checking /// this item. This is then used to get the type in the `type_of` query. /// /// For example consider `fn f<'a>(x: &'a i32) -> impl Sized + 'a { x }`. /// This is lowered to give HIR something like /// - /// type f<'a>::_Return<'_a> = impl Sized + '_a; - /// fn f<'a>(x: &'a i32) -> f<'static>::_Return<'a> { x } + /// type f<'a>::_Return<'_x> = impl Sized + '_x; + /// fn f<'a>(x: &'a i32) -> f<'a>::_Return<'a> { x } /// /// When checking the return type record the type from the return and the /// type used in the return value. In this case they might be `_Return<'1>` @@ -95,118 +37,102 @@ impl<'tcx> RegionInferenceContext<'tcx> { /// /// Once we to this method, we have completed region inference and want to /// call `infer_opaque_definition_from_instantiation` to get the inferred - /// type of `_Return<'_a>`. `infer_opaque_definition_from_instantiation` + /// type of `_Return<'_x>`. `infer_opaque_definition_from_instantiation` /// compares lifetimes directly, so we need to map the inference variables /// back to concrete lifetimes: `'static`, `ReEarlyParam` or `ReLateParam`. /// - /// First we map all the lifetimes in the concrete type to an equal - /// universal region that occurs in the concrete type's args, in this case - /// this would result in `&'1 i32`. We only consider regions in the args + /// First we map the regions in the the generic parameters `_Return<'1>` to + /// their `external_name` giving `_Return<'a>`. This step is a bit involved. + /// See the [rustc-dev-guide chapter] for more info. + /// + /// Then we map all the lifetimes in the concrete type to an equal + /// universal region that occurs in the opaque type's args, in this case + /// this would result in `&'a i32`. We only consider regions in the args /// in case there is an equal region that does not. For example, this should /// be allowed: /// `fn f<'a: 'b, 'b: 'a>(x: *mut &'b i32) -> impl Sized + 'a { x }` /// - /// Then we map the regions in both the type and the generic parameters to their - /// `external_name` giving `concrete_type = &'a i32`, - /// `args = ['static, 'a]`. This will then allow - /// `infer_opaque_definition_from_instantiation` to determine that - /// `_Return<'_a> = &'_a i32`. + /// This will then allow `infer_opaque_definition_from_instantiation` to + /// determine that `_Return<'_x> = &'_x i32`. /// /// There's a slight complication around closures. Given /// `fn f<'a: 'a>() { || {} }` the closure's type is something like /// `f::<'a>::{{closure}}`. The region parameter from f is essentially /// ignored by type checking so ends up being inferred to an empty region. /// Calling `universal_upper_bound` for such a region gives `fr_fn_body`, - /// which has no `external_name` in which case we use `'empty` as the + /// which has no `external_name` in which case we use `'{erased}` as the /// region to pass to `infer_opaque_definition_from_instantiation`. + /// + /// [rustc-dev-guide chapter]: + /// https://rustc-dev-guide.rust-lang.org/opaque-types-region-infer-restrictions.html #[instrument(level = "debug", skip(self, infcx), ret)] pub(crate) fn infer_opaque_types( &self, infcx: &InferCtxt<'tcx>, opaque_ty_decls: FxIndexMap, OpaqueHiddenType<'tcx>>, ) -> FxIndexMap> { - self.check_unique(infcx, &opaque_ty_decls); - let mut result: FxIndexMap> = FxIndexMap::default(); - - let member_constraints: FxIndexMap<_, _> = self - .member_constraints - .all_indices() - .map(|ci| (self.member_constraints[ci].key, ci)) - .collect(); - debug!(?member_constraints); + let mut decls_modulo_regions: FxIndexMap, (OpaqueTypeKey<'tcx>, Span)> = + FxIndexMap::default(); for (opaque_type_key, concrete_type) in opaque_ty_decls { - let args = opaque_type_key.args; - debug!(?concrete_type, ?args); + debug!(?opaque_type_key, ?concrete_type); - let mut arg_regions = vec![self.universal_regions.fr_static]; + let mut arg_regions: Vec<(ty::RegionVid, ty::Region<'_>)> = + vec![(self.universal_regions.fr_static, infcx.tcx.lifetimes.re_static)]; - let to_universal_region = |vid, arg_regions: &mut Vec<_>| match self.universal_name(vid) - { - Some(region) => { - let vid = self.universal_regions.to_region_vid(region); - arg_regions.push(vid); - region - } - None => { - arg_regions.push(vid); - ty::Region::new_error_with_message( - infcx.tcx, - concrete_type.span, - "opaque type with non-universal region args", - ) - } - }; + let opaque_type_key = + opaque_type_key.fold_captured_lifetime_args(infcx.tcx, |region| { + // Use the SCC representative instead of directly using `region`. + // See [rustc-dev-guide chapter] § "Strict lifetime equality". + let scc = self.constraint_sccs.scc(region.as_var()); + let vid = self.scc_representatives[scc]; + let named = match self.definitions[vid].origin { + // Iterate over all universal regions in a consistent order and find the + // *first* equal region. This makes sure that equal lifetimes will have + // the same name and simplifies subsequent handling. + // See [rustc-dev-guide chapter] § "Semantic lifetime equality". + NllRegionVariableOrigin::FreeRegion => self + .universal_regions + .universal_regions() + .filter(|&ur| { + // See [rustc-dev-guide chapter] § "Closure restrictions". + !matches!( + self.universal_regions.region_classification(ur), + Some(RegionClassification::External) + ) + }) + .find(|&ur| self.universal_region_relations.equal(vid, ur)) + .map(|ur| self.definitions[ur].external_name.unwrap()), + NllRegionVariableOrigin::Placeholder(placeholder) => { + Some(ty::Region::new_placeholder(infcx.tcx, placeholder)) + } + NllRegionVariableOrigin::Existential { .. } => None, + } + .unwrap_or_else(|| { + ty::Region::new_error_with_message( + infcx.tcx, + concrete_type.span, + "opaque type with non-universal region args", + ) + }); - // Start by inserting universal regions from the member_constraint choice regions. - // This will ensure they get precedence when folding the regions in the concrete type. - if let Some(&ci) = member_constraints.get(&opaque_type_key) { - for &vid in self.member_constraints.choice_regions(ci) { - to_universal_region(vid, &mut arg_regions); - } - } - debug!(?arg_regions); - - // Next, insert universal regions from args, so we can translate regions that appear - // in them but are not subject to member constraints, for instance closure args. - let universal_args = infcx.tcx.fold_regions(args, |region, _| { - if let ty::RePlaceholder(..) = region.kind() { - // Higher kinded regions don't need remapping, they don't refer to anything outside of this the args. - return region; - } - let vid = self.to_region_vid(region); - to_universal_region(vid, &mut arg_regions) - }); - debug!(?universal_args); - debug!(?arg_regions); - - // Deduplicate the set of regions while keeping the chosen order. - let arg_regions = arg_regions.into_iter().collect::>(); - debug!(?arg_regions); - - let universal_concrete_type = - infcx.tcx.fold_regions(concrete_type, |region, _| match *region { - ty::ReVar(vid) => arg_regions - .iter() - .find(|ur_vid| self.eval_equal(vid, **ur_vid)) - .and_then(|ur_vid| self.definitions[*ur_vid].external_name) - .unwrap_or(infcx.tcx.lifetimes.re_erased), - ty::RePlaceholder(_) => ty::Region::new_error_with_message( - infcx.tcx, - concrete_type.span, - "hidden type contains placeholders, we don't support higher kinded opaques yet", - ), - _ => region, + arg_regions.push((vid, named)); + named }); - debug!(?universal_concrete_type); + debug!(?opaque_type_key, ?arg_regions); + + let concrete_type = infcx.tcx.fold_regions(concrete_type, |region, _| { + arg_regions + .iter() + .find(|&&(arg_vid, _)| self.eval_equal(region.as_var(), arg_vid)) + .map(|&(_, arg_named)| arg_named) + .unwrap_or(infcx.tcx.lifetimes.re_erased) + }); + debug!(?concrete_type); - let opaque_type_key = - OpaqueTypeKey { def_id: opaque_type_key.def_id, args: universal_args }; - let ty = infcx.infer_opaque_definition_from_instantiation( - opaque_type_key, - universal_concrete_type, - ); + let ty = + infcx.infer_opaque_definition_from_instantiation(opaque_type_key, concrete_type); // Sometimes two opaque types are the same only after we remap the generic parameters // back to the opaque type definition. E.g. we may have `OpaqueType` mapped to `(X, Y)` // and `OpaqueType` mapped to `(Y, X)`, and those are the same, but we only know that @@ -234,6 +160,29 @@ impl<'tcx> RegionInferenceContext<'tcx> { OpaqueHiddenType { ty, span: concrete_type.span }, ); } + + // Check that all opaque types have the same region parameters if they have the same + // non-region parameters. This is necessary because within the new solver we perform + // various query operations modulo regions, and thus could unsoundly select some impls + // that don't hold. + if !ty.references_error() + && let Some((prev_decl_key, prev_span)) = decls_modulo_regions.insert( + infcx.tcx.erase_regions(opaque_type_key), + (opaque_type_key, concrete_type.span), + ) + && let Some((arg1, arg2)) = std::iter::zip( + prev_decl_key.iter_captured_args(infcx.tcx).map(|(_, arg)| arg), + opaque_type_key.iter_captured_args(infcx.tcx).map(|(_, arg)| arg), + ) + .find(|(arg1, arg2)| arg1 != arg2) + { + infcx.dcx().emit_err(LifetimeMismatchOpaqueParam { + arg: arg1, + prev: arg2, + span: prev_span, + prev_span: concrete_type.span, + }); + } } result } @@ -422,42 +371,46 @@ fn check_opaque_type_well_formed<'tcx>( } } -fn check_opaque_type_parameter_valid( - tcx: TyCtxt<'_>, - opaque_type_key: OpaqueTypeKey<'_>, +/// Opaque type parameter validity check as documented in the [rustc-dev-guide chapter]. +/// +/// [rustc-dev-guide chapter]: +/// https://rustc-dev-guide.rust-lang.org/opaque-types-region-infer-restrictions.html +fn check_opaque_type_parameter_valid<'tcx>( + tcx: TyCtxt<'tcx>, + opaque_type_key: OpaqueTypeKey<'tcx>, span: Span, ) -> Result<(), ErrorGuaranteed> { - let opaque_ty_hir = tcx.hir().expect_item(opaque_type_key.def_id); - let (parent, is_ty_alias) = match opaque_ty_hir.expect_opaque_ty().origin { - OpaqueTyOrigin::TyAlias { parent, .. } => (parent, true), - OpaqueTyOrigin::AsyncFn(parent) | OpaqueTyOrigin::FnReturn(parent) => (parent, false), - }; - - let parent_generics = tcx.generics_of(parent); + let opaque_generics = tcx.generics_of(opaque_type_key.def_id); + let opaque_env = LazyOpaqueTyEnv::new(tcx, opaque_type_key.def_id); let mut seen_params: FxIndexMap<_, Vec<_>> = FxIndexMap::default(); - // Only check the parent generics, which will ignore any of the - // duplicated lifetime args that come from reifying late-bounds. - for (i, arg) in opaque_type_key.args.iter().take(parent_generics.count()).enumerate() { + for (i, arg) in opaque_type_key.iter_captured_args(tcx) { let arg_is_param = match arg.unpack() { GenericArgKind::Type(ty) => matches!(ty.kind(), ty::Param(_)), - GenericArgKind::Lifetime(lt) if is_ty_alias => { + GenericArgKind::Lifetime(lt) => { matches!(*lt, ty::ReEarlyParam(_) | ty::ReLateParam(_)) + || (lt.is_static() && opaque_env.param_equal_static(i)) } - // FIXME(#113916): we can't currently check for unique lifetime params, - // see that issue for more. We will also have to ignore unused lifetime - // params for RPIT, but that's comparatively trivial ✨ - GenericArgKind::Lifetime(_) => continue, GenericArgKind::Const(ct) => matches!(ct.kind(), ty::ConstKind::Param(_)), }; if arg_is_param { - seen_params.entry(arg).or_default().push(i); + // Register if the same lifetime appears multiple times in the generic args. + // There is an exception when the opaque type *requires* the lifetimes to be equal. + // See [rustc-dev-guide chapter] § "An exception to uniqueness rule". + let seen_where = seen_params.entry(arg).or_default(); + if !seen_where.first().is_some_and(|&prev_i| opaque_env.params_equal(i, prev_i)) { + seen_where.push(i); + } } else { // Prevent `fn foo() -> Foo` from being defining. - let opaque_param = parent_generics.param_at(i, tcx); + let opaque_param = opaque_generics.param_at(i, tcx); let kind = opaque_param.kind.descr(); + if let Err(guar) = opaque_env.param_is_error(i) { + return Err(guar); + } + return Err(tcx.dcx().emit_err(NonGenericOpaqueTypeParam { ty: arg, kind, @@ -469,10 +422,10 @@ fn check_opaque_type_parameter_valid( for (_, indices) in seen_params { if indices.len() > 1 { - let descr = parent_generics.param_at(indices[0], tcx).kind.descr(); + let descr = opaque_generics.param_at(indices[0], tcx).kind.descr(); let spans: Vec<_> = indices .into_iter() - .map(|i| tcx.def_span(parent_generics.param_at(i, tcx).def_id)) + .map(|i| tcx.def_span(opaque_generics.param_at(i, tcx).def_id)) .collect(); #[allow(rustc::diagnostic_outside_of_impl)] #[allow(rustc::untranslatable_diagnostic)] @@ -486,3 +439,91 @@ fn check_opaque_type_parameter_valid( Ok(()) } + +/// Computes if an opaque type requires a lifetime parameter to be equal to +/// another one or to the `'static` lifetime. +/// These requirements are derived from the explicit and implied bounds. +struct LazyOpaqueTyEnv<'tcx> { + tcx: TyCtxt<'tcx>, + def_id: LocalDefId, + + /// Equal parameters will have the same name. Computed Lazily. + /// Example: + /// `type Opaque<'a: 'static, 'b: 'c, 'c: 'b> = impl Sized;` + /// Identity args: `['a, 'b, 'c]` + /// Canonical args: `['static, 'b, 'b]` + canonical_args: std::cell::OnceCell>, +} + +impl<'tcx> LazyOpaqueTyEnv<'tcx> { + pub fn new(tcx: TyCtxt<'tcx>, def_id: LocalDefId) -> Self { + Self { tcx, def_id, canonical_args: std::cell::OnceCell::new() } + } + + pub fn param_equal_static(&self, param_index: usize) -> bool { + self.get_canonical_args()[param_index].expect_region().is_static() + } + + pub fn params_equal(&self, param1: usize, param2: usize) -> bool { + let canonical_args = self.get_canonical_args(); + canonical_args[param1] == canonical_args[param2] + } + + pub fn param_is_error(&self, param_index: usize) -> Result<(), ErrorGuaranteed> { + self.get_canonical_args()[param_index].error_reported() + } + + fn get_canonical_args(&self) -> ty::GenericArgsRef<'tcx> { + use rustc_hir as hir; + use rustc_infer::infer::outlives::env::OutlivesEnvironment; + use rustc_trait_selection::traits::outlives_bounds::InferCtxtExt as _; + + if let Some(&canonical_args) = self.canonical_args.get() { + return canonical_args; + } + + let &Self { tcx, def_id, .. } = self; + let origin = tcx.opaque_type_origin(def_id); + let parent = match origin { + hir::OpaqueTyOrigin::FnReturn(parent) + | hir::OpaqueTyOrigin::AsyncFn(parent) + | hir::OpaqueTyOrigin::TyAlias { parent, .. } => parent, + }; + let param_env = tcx.param_env(parent); + let args = GenericArgs::identity_for_item(tcx, parent).extend_to( + tcx, + def_id.to_def_id(), + |param, _| { + tcx.map_opaque_lifetime_to_parent_lifetime(param.def_id.expect_local()).into() + }, + ); + + let infcx = tcx.infer_ctxt().build(); + let ocx = ObligationCtxt::new(&infcx); + + let wf_tys = ocx.assumed_wf_types(param_env, parent).unwrap_or_else(|_| { + tcx.dcx().span_delayed_bug(tcx.def_span(def_id), "error getting implied bounds"); + Default::default() + }); + let implied_bounds = infcx.implied_bounds_tys(param_env, parent, &wf_tys); + let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds); + + let mut seen = vec![tcx.lifetimes.re_static]; + let canonical_args = tcx.fold_regions(args, |r1, _| { + if r1.is_error() { + r1 + } else if let Some(&r2) = seen.iter().find(|&&r2| { + let free_regions = outlives_env.free_region_map(); + free_regions.sub_free_regions(tcx, r1, r2) + && free_regions.sub_free_regions(tcx, r2, r1) + }) { + r2 + } else { + seen.push(r1); + r1 + } + }); + self.canonical_args.set(canonical_args).unwrap(); + canonical_args + } +} diff --git a/compiler/rustc_borrowck/src/type_check/free_region_relations.rs b/compiler/rustc_borrowck/src/type_check/free_region_relations.rs index 86d20599a2a88..7553e3ee04fb4 100644 --- a/compiler/rustc_borrowck/src/type_check/free_region_relations.rs +++ b/compiler/rustc_borrowck/src/type_check/free_region_relations.rs @@ -164,6 +164,13 @@ impl UniversalRegionRelations<'_> { self.outlives.contains(fr1, fr2) } + /// Returns `true` if fr1 is known to equal fr2. + /// + /// This will only ever be true for universally quantified regions. + pub(crate) fn equal(&self, fr1: RegionVid, fr2: RegionVid) -> bool { + self.outlives.contains(fr1, fr2) && self.outlives.contains(fr2, fr1) + } + /// Returns a vector of free regions `x` such that `fr1: x` is /// known to hold. pub(crate) fn regions_outlived_by(&self, fr1: RegionVid) -> Vec { diff --git a/compiler/rustc_borrowck/src/type_check/mod.rs b/compiler/rustc_borrowck/src/type_check/mod.rs index a206aac0467f4..b72dccb2ebd0d 100644 --- a/compiler/rustc_borrowck/src/type_check/mod.rs +++ b/compiler/rustc_borrowck/src/type_check/mod.rs @@ -229,6 +229,22 @@ pub(crate) fn type_check<'mir, 'tcx>( ); } + // Convert all regions to nll vars. + let (opaque_type_key, hidden_type) = + infcx.tcx.fold_regions((opaque_type_key, hidden_type), |region, _| { + match region.kind() { + ty::ReVar(_) => region, + ty::RePlaceholder(placeholder) => checker + .borrowck_context + .constraints + .placeholder_region(infcx, placeholder), + _ => ty::Region::new_var( + infcx.tcx, + checker.borrowck_context.universal_regions.to_region_vid(region), + ), + } + }); + (opaque_type_key, hidden_type) }) .collect(); diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs index 6ce53ccc8cd7a..0be1a1ab39d69 100644 --- a/compiler/rustc_middle/src/ty/mod.rs +++ b/compiler/rustc_middle/src/ty/mod.rs @@ -832,6 +832,38 @@ pub struct OpaqueTypeKey<'tcx> { pub args: GenericArgsRef<'tcx>, } +impl<'tcx> OpaqueTypeKey<'tcx> { + pub fn iter_captured_args( + self, + tcx: TyCtxt<'tcx>, + ) -> impl Iterator)> { + std::iter::zip(self.args, tcx.variances_of(self.def_id)).enumerate().filter_map( + |(i, (arg, v))| match (arg.unpack(), v) { + (_, ty::Invariant) => Some((i, arg)), + (ty::GenericArgKind::Lifetime(_), ty::Bivariant) => None, + _ => bug!("unexpected opaque type arg variance"), + }, + ) + } + + pub fn fold_captured_lifetime_args( + self, + tcx: TyCtxt<'tcx>, + mut f: impl FnMut(Region<'tcx>) -> Region<'tcx>, + ) -> Self { + let Self { def_id, args } = self; + let args = std::iter::zip(args, tcx.variances_of(def_id)).map(|(arg, v)| { + match (arg.unpack(), v) { + (ty::GenericArgKind::Lifetime(_), ty::Bivariant) => arg, + (ty::GenericArgKind::Lifetime(lt), _) => f(lt).into(), + _ => arg, + } + }); + let args = tcx.mk_args_from_iter(args); + Self { def_id, args } + } +} + #[derive(Copy, Clone, Debug, TypeFoldable, TypeVisitable, HashStable, TyEncodable, TyDecodable)] pub struct OpaqueHiddenType<'tcx> { /// The span of this particular definition of the opaque type. So diff --git a/tests/ui/impl-trait/defining-use-captured-non-universal-region.infer.stderr b/tests/ui/impl-trait/defining-use-captured-non-universal-region.infer.stderr new file mode 100644 index 0000000000000..ded9a92d8e8c4 --- /dev/null +++ b/tests/ui/impl-trait/defining-use-captured-non-universal-region.infer.stderr @@ -0,0 +1,12 @@ +error[E0792]: expected generic lifetime parameter, found `'_` + --> $DIR/defining-use-captured-non-universal-region.rs:13:18 + | +LL | fn foo<'a>() -> impl Sized + 'a { + | -- this generic parameter must be used with a generic lifetime parameter +... +LL | let i: i32 = foo::<'_>(); + | ^^^^^^^^^^^ + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/impl-trait/defining-use-captured-non-universal-region.rs b/tests/ui/impl-trait/defining-use-captured-non-universal-region.rs new file mode 100644 index 0000000000000..e18302dc061a3 --- /dev/null +++ b/tests/ui/impl-trait/defining-use-captured-non-universal-region.rs @@ -0,0 +1,22 @@ +// This was an ICE. See #110726. + +//@ revisions: statik infer fixed +//@ [fixed] check-pass +#![allow(unconditional_recursion)] + +fn foo<'a>() -> impl Sized + 'a { + #[cfg(statik)] + let i: i32 = foo::<'static>(); + //[statik]~^ ERROR expected generic lifetime parameter, found `'static` + + #[cfg(infer)] + let i: i32 = foo::<'_>(); + //[infer]~^ ERROR expected generic lifetime parameter, found `'_` + + #[cfg(fixed)] + let i: i32 = foo::<'a>(); + + i +} + +fn main() {} diff --git a/tests/ui/impl-trait/defining-use-captured-non-universal-region.statik.stderr b/tests/ui/impl-trait/defining-use-captured-non-universal-region.statik.stderr new file mode 100644 index 0000000000000..43beb29f9ec46 --- /dev/null +++ b/tests/ui/impl-trait/defining-use-captured-non-universal-region.statik.stderr @@ -0,0 +1,12 @@ +error[E0792]: expected generic lifetime parameter, found `'static` + --> $DIR/defining-use-captured-non-universal-region.rs:9:18 + | +LL | fn foo<'a>() -> impl Sized + 'a { + | -- cannot use static lifetime; use a bound lifetime instead or remove the lifetime parameter from the opaque type +LL | #[cfg(statik)] +LL | let i: i32 = foo::<'static>(); + | ^^^^^^^^^^^^^^^^ + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/impl-trait/defining-use-uncaptured-non-universal-region-2.rs b/tests/ui/impl-trait/defining-use-uncaptured-non-universal-region-2.rs new file mode 100644 index 0000000000000..56e099c28d219 --- /dev/null +++ b/tests/ui/impl-trait/defining-use-uncaptured-non-universal-region-2.rs @@ -0,0 +1,74 @@ +// issue: #110623 +//@ check-pass + +use std::{collections::BTreeMap, num::ParseIntError, str::FromStr}; + +enum FileSystem { + File(usize), + Directory(BTreeMap), +} + +impl FromStr for FileSystem { + type Err = ParseIntError; + + fn from_str(s: &str) -> Result { + if s.starts_with("dir") { + Ok(Self::new_dir()) + } else { + Ok(Self::File(s.split_whitespace().next().unwrap().parse()?)) + } + } +} + +impl FileSystem { + fn new_dir() -> FileSystem { + FileSystem::Directory(BTreeMap::new()) + } + + fn insert(&mut self, name: String, other: FileSystem) -> Option { + match self { + FileSystem::File(_) => panic!("can only insert into directory!"), + FileSystem::Directory(tree) => tree.insert(name, other), + } + } + + // Recursively build a tree from commands. This uses (abuses?) + // the fact that `cd /` only appears at the start and that + // subsequent `cd`s can only move ONE level to use the recursion + // stack as the filesystem stack + fn build<'a>( + &mut self, + mut commands: impl Iterator + 'a, + ) -> Option + 'a> { + let cmd = commands.next()?; + let mut elements = cmd.lines(); + match elements.next().map(str::trim) { + Some("cd /") | None => self.build(commands), + Some("cd ..") => { + // return to higher scope + Some(commands) + } + Some("ls") => { + for item in elements { + let name = item.split_whitespace().last().unwrap(); + let prior = self.insert(name.to_string(), item.parse().unwrap()); + debug_assert!(prior.is_none()); + } + // continue on + self.build(commands) + } + Some(other_cd) => { + let name = other_cd + .trim() + .strip_prefix("cd ") + .expect("expected a cd command"); + let mut directory = FileSystem::new_dir(); + let further_commands = directory.build(commands); + self.insert(name.to_string(), directory); + self.build(further_commands?) // THIS LINE FAILS TO COMPILE + } + } + } +} + +fn main() {} diff --git a/tests/ui/impl-trait/defining-use-uncaptured-non-universal-region-3.rs b/tests/ui/impl-trait/defining-use-uncaptured-non-universal-region-3.rs new file mode 100644 index 0000000000000..a6dcad3face0a --- /dev/null +++ b/tests/ui/impl-trait/defining-use-uncaptured-non-universal-region-3.rs @@ -0,0 +1,13 @@ +//@ check-pass + +#![feature(adt_const_params)] +#![allow(incomplete_features)] + +trait Bar {} +impl Bar<"asdf"> for () {} + +fn foo() -> impl Bar<"asdf"> { + () +} + +fn main() {} diff --git a/tests/ui/impl-trait/defining-use-uncaptured-non-universal-region.rs b/tests/ui/impl-trait/defining-use-uncaptured-non-universal-region.rs new file mode 100644 index 0000000000000..f90ff51c651aa --- /dev/null +++ b/tests/ui/impl-trait/defining-use-uncaptured-non-universal-region.rs @@ -0,0 +1,16 @@ +// issue: #111906 +//@ check-pass + +#![allow(unconditional_recursion)] + +fn foo<'a: 'a>() -> impl Sized { + let _: () = foo::<'a>(); + loop {} +} + +fn bar<'a: 'a>() -> impl Sized + 'a { + let _: *mut &'a () = bar::<'a>(); + loop {} +} + +fn main() {} diff --git a/tests/ui/impl-trait/erased-regions-in-hidden-ty.current.stderr b/tests/ui/impl-trait/erased-regions-in-hidden-ty.current.stderr index 1d648162113f3..78ef8ec404c9b 100644 --- a/tests/ui/impl-trait/erased-regions-in-hidden-ty.current.stderr +++ b/tests/ui/impl-trait/erased-regions-in-hidden-ty.current.stderr @@ -1,4 +1,4 @@ -error: {foo::{closure#0} closure_kind_ty=i8 closure_sig_as_fn_ptr_ty=extern "rust-call" fn(()) upvar_tys=()} +error: {foo<'{erased}>::{closure#0} closure_kind_ty=i8 closure_sig_as_fn_ptr_ty=extern "rust-call" fn(()) upvar_tys=()} --> $DIR/erased-regions-in-hidden-ty.rs:12:36 | LL | fn foo<'a: 'a>(x: &'a Vec) -> impl Fn() + 'static { diff --git a/tests/ui/impl-trait/erased-regions-in-hidden-ty.next.stderr b/tests/ui/impl-trait/erased-regions-in-hidden-ty.next.stderr index 1d648162113f3..78ef8ec404c9b 100644 --- a/tests/ui/impl-trait/erased-regions-in-hidden-ty.next.stderr +++ b/tests/ui/impl-trait/erased-regions-in-hidden-ty.next.stderr @@ -1,4 +1,4 @@ -error: {foo::{closure#0} closure_kind_ty=i8 closure_sig_as_fn_ptr_ty=extern "rust-call" fn(()) upvar_tys=()} +error: {foo<'{erased}>::{closure#0} closure_kind_ty=i8 closure_sig_as_fn_ptr_ty=extern "rust-call" fn(()) upvar_tys=()} --> $DIR/erased-regions-in-hidden-ty.rs:12:36 | LL | fn foo<'a: 'a>(x: &'a Vec) -> impl Fn() + 'static { diff --git a/tests/ui/impl-trait/erased-regions-in-hidden-ty.rs b/tests/ui/impl-trait/erased-regions-in-hidden-ty.rs index 9d71685f179e4..e60f1badcae0f 100644 --- a/tests/ui/impl-trait/erased-regions-in-hidden-ty.rs +++ b/tests/ui/impl-trait/erased-regions-in-hidden-ty.rs @@ -10,7 +10,7 @@ // Make sure that the compiler can handle `ReErased` in the hidden type of an opaque. fn foo<'a: 'a>(x: &'a Vec) -> impl Fn() + 'static { - //~^ ERROR 'a/#0>::{closure#0} closure_kind_ty=i8 closure_sig_as_fn_ptr_ty=extern "rust-call" fn(()) upvar_tys=()} + //~^ ERROR '{erased}>::{closure#0} closure_kind_ty=i8 closure_sig_as_fn_ptr_ty=extern "rust-call" fn(()) upvar_tys=()} // Can't write whole type because of lack of path sanitization || () } diff --git a/tests/ui/impl-trait/impl-fn-predefined-lifetimes.rs b/tests/ui/impl-trait/impl-fn-predefined-lifetimes.rs index 1577866237544..199cbbf4fcc9b 100644 --- a/tests/ui/impl-trait/impl-fn-predefined-lifetimes.rs +++ b/tests/ui/impl-trait/impl-fn-predefined-lifetimes.rs @@ -2,10 +2,8 @@ use std::fmt::Debug; fn a<'a>() -> impl Fn(&'a u8) -> (impl Debug + '_) { - //~^ ERROR cannot resolve opaque type - |x| x - //~^ ERROR concrete type differs from previous defining opaque type use + //~^ ERROR expected generic lifetime parameter, found `'_` } fn _b<'a>() -> impl Fn(&'a u8) -> (impl Debug + 'a) { diff --git a/tests/ui/impl-trait/impl-fn-predefined-lifetimes.stderr b/tests/ui/impl-trait/impl-fn-predefined-lifetimes.stderr index c19420bbb0ceb..6064b09ef0927 100644 --- a/tests/ui/impl-trait/impl-fn-predefined-lifetimes.stderr +++ b/tests/ui/impl-trait/impl-fn-predefined-lifetimes.stderr @@ -1,21 +1,11 @@ -error: concrete type differs from previous defining opaque type use - --> $DIR/impl-fn-predefined-lifetimes.rs:7:9 - | -LL | |x| x - | ^ expected `impl Debug + '_`, got `&u8` - | -note: previous use here - --> $DIR/impl-fn-predefined-lifetimes.rs:7:5 - | -LL | |x| x - | ^^^^^ - -error[E0720]: cannot resolve opaque type - --> $DIR/impl-fn-predefined-lifetimes.rs:4:35 +error[E0792]: expected generic lifetime parameter, found `'_` + --> $DIR/impl-fn-predefined-lifetimes.rs:5:9 | LL | fn a<'a>() -> impl Fn(&'a u8) -> (impl Debug + '_) { - | ^^^^^^^^^^^^^^^ cannot resolve opaque type + | -- this generic parameter must be used with a generic lifetime parameter +LL | |x| x + | ^ -error: aborting due to 2 previous errors +error: aborting due to 1 previous error -For more information about this error, try `rustc --explain E0720`. +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.rs b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.rs index 41d5f0f64498d..5b3a4eb53ff15 100644 --- a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.rs +++ b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.rs @@ -5,6 +5,7 @@ trait Foo { fn bar<'other: 'a>() -> impl Sized + 'a {} //~^ ERROR use of undeclared lifetime name `'a` //~| ERROR use of undeclared lifetime name `'a` + //~| ERROR expected generic lifetime parameter, found `'static` } fn main() {} diff --git a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.stderr b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.stderr index b0832eb33ca74..8975578dabd84 100644 --- a/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.stderr +++ b/tests/ui/impl-trait/in-trait/bad-item-bound-within-rpitit-2.stderr @@ -28,6 +28,15 @@ help: consider introducing lifetime `'a` here LL | trait Foo<'a> { | ++++ -error: aborting due to 2 previous errors +error[E0792]: expected generic lifetime parameter, found `'static` + --> $DIR/bad-item-bound-within-rpitit-2.rs:5:45 + | +LL | fn bar<'other: 'a>() -> impl Sized + 'a {} + | ------ ^^ + | | + | cannot use static lifetime; use a bound lifetime instead or remove the lifetime parameter from the opaque type + +error: aborting due to 3 previous errors -For more information about this error, try `rustc --explain E0261`. +Some errors have detailed explanations: E0261, E0792. +For more information about an error, try `rustc --explain E0261`. diff --git a/tests/ui/impl-trait/rpit/early_bound.rs b/tests/ui/impl-trait/rpit/early_bound.rs index 6dda687929c4d..005bcea59f243 100644 --- a/tests/ui/impl-trait/rpit/early_bound.rs +++ b/tests/ui/impl-trait/rpit/early_bound.rs @@ -5,6 +5,7 @@ fn test<'a: 'a>(n: bool) -> impl Sized + 'a { let true = n else { loop {} }; let _ = || { let _ = identity::<&'a ()>(test(false)); + //~^ ERROR expected generic lifetime parameter, found `'_` }; loop {} } diff --git a/tests/ui/impl-trait/rpit/early_bound.stderr b/tests/ui/impl-trait/rpit/early_bound.stderr index 780dea4e284ee..b0c7bd4199cc2 100644 --- a/tests/ui/impl-trait/rpit/early_bound.stderr +++ b/tests/ui/impl-trait/rpit/early_bound.stderr @@ -1,3 +1,12 @@ +error[E0792]: expected generic lifetime parameter, found `'_` + --> $DIR/early_bound.rs:7:17 + | +LL | fn test<'a: 'a>(n: bool) -> impl Sized + 'a { + | -- this generic parameter must be used with a generic lifetime parameter +... +LL | let _ = identity::<&'a ()>(test(false)); + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + error: concrete type differs from previous defining opaque type use --> $DIR/early_bound.rs:3:29 | @@ -10,5 +19,6 @@ note: previous use here LL | let _ = identity::<&'a ()>(test(false)); | ^^^^^^^^^^^ -error: aborting due to 1 previous error +error: aborting due to 2 previous errors +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/impl-trait/rpit/non-defining-use-lifetimes.rs b/tests/ui/impl-trait/rpit/non-defining-use-lifetimes.rs new file mode 100644 index 0000000000000..5e04e6b091adc --- /dev/null +++ b/tests/ui/impl-trait/rpit/non-defining-use-lifetimes.rs @@ -0,0 +1,37 @@ +// issue: #111935 + +#![allow(unconditional_recursion)] + +// Lt indirection is necessary to make the lifetime of the function late-bound, +// in order to bypass some other bugs. +type Lt<'lt> = Option<*mut &'lt ()>; + +mod statik { + use super::*; + // invalid defining use: Opaque<'static> := () + fn foo<'a>(_: Lt<'a>) -> impl Sized + 'a { + let _: () = foo(Lt::<'static>::None); + //~^ ERROR expected generic lifetime parameter, found `'static` + } +} + +mod infer { + use super::*; + // invalid defining use: Opaque<'_> := () + fn foo<'a>(_: Lt<'a>) -> impl Sized + 'a { + let _: () = foo(Lt::<'_>::None); + //~^ ERROR expected generic lifetime parameter, found `'_` + } +} + +mod equal { + use super::*; + // invalid defining use: Opaque<'a, 'a> := () + // because of the use of equal lifetimes in args + fn foo<'a, 'b>(_: Lt<'a>, _: Lt<'b>) -> impl Sized + 'a + 'b { + let _: () = foo(Lt::<'a>::None, Lt::<'a>::None); + //~^ ERROR non-defining opaque type use in defining scope + } +} + +fn main() {} diff --git a/tests/ui/impl-trait/rpit/non-defining-use-lifetimes.stderr b/tests/ui/impl-trait/rpit/non-defining-use-lifetimes.stderr new file mode 100644 index 0000000000000..d2a224601fbe6 --- /dev/null +++ b/tests/ui/impl-trait/rpit/non-defining-use-lifetimes.stderr @@ -0,0 +1,31 @@ +error[E0792]: expected generic lifetime parameter, found `'static` + --> $DIR/non-defining-use-lifetimes.rs:13:16 + | +LL | fn foo<'a>(_: Lt<'a>) -> impl Sized + 'a { + | -- cannot use static lifetime; use a bound lifetime instead or remove the lifetime parameter from the opaque type +LL | let _: () = foo(Lt::<'static>::None); + | ^^ + +error[E0792]: expected generic lifetime parameter, found `'_` + --> $DIR/non-defining-use-lifetimes.rs:22:16 + | +LL | fn foo<'a>(_: Lt<'a>) -> impl Sized + 'a { + | -- this generic parameter must be used with a generic lifetime parameter +LL | let _: () = foo(Lt::<'_>::None); + | ^^ + +error: non-defining opaque type use in defining scope + --> $DIR/non-defining-use-lifetimes.rs:32:16 + | +LL | let _: () = foo(Lt::<'a>::None, Lt::<'a>::None); + | ^^ + | +note: lifetime used multiple times + --> $DIR/non-defining-use-lifetimes.rs:31:58 + | +LL | fn foo<'a, 'b>(_: Lt<'a>, _: Lt<'b>) -> impl Sized + 'a + 'b { + | ^^ ^^ + +error: aborting due to 3 previous errors + +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/type-alias-impl-trait/bivariant-duplicate-lifetime-unconstrained.rs b/tests/ui/type-alias-impl-trait/bivariant-duplicate-lifetime-unconstrained.rs new file mode 100644 index 0000000000000..3b83b2e544b01 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/bivariant-duplicate-lifetime-unconstrained.rs @@ -0,0 +1,18 @@ +// The defining use below has an unconstrained lifetime argument. +// Opaque<'{empty}, 'a> := (); +// Make sure we accept it because the lifetime parameter in such position is +// irrelevant - it is an artifact of how we internally represent opaque +// generics. +// See issue #122307 for details. + +//@ check-pass +#![feature(type_alias_impl_trait)] +#![allow(unconditional_recursion)] + +type Opaque<'a> = impl Sized + 'a; + +fn test<'a>() -> Opaque<'a> { + let _: () = test::<'a>(); +} + +fn main() {} diff --git a/tests/ui/type-alias-impl-trait/defined-by-user-annotation.rs b/tests/ui/type-alias-impl-trait/defined-by-user-annotation.rs index d97a3010a17a0..0e1d44e7bb3a3 100644 --- a/tests/ui/type-alias-impl-trait/defined-by-user-annotation.rs +++ b/tests/ui/type-alias-impl-trait/defined-by-user-annotation.rs @@ -8,12 +8,24 @@ impl Equate for T { type Proj = T; } trait Indirect { type Ty; } impl> Indirect for (A, B) { type Ty = (); } -type Opq = impl Sized; -fn define_1(_: Opq) { - let _ = None::<<(Opq, u8) as Indirect>::Ty>; +mod basic { + use super::*; + type Opq = impl Sized; + fn define_1(_: Opq) { + let _ = None::<<(Opq, u8) as Indirect>::Ty>; + } + fn define_2() -> Opq { + 0u8 + } } -fn define_2() -> Opq { - 0u8 + +// `Opq<'a> == &'b u8` shouldn't be an error because `'a == 'b`. +mod lifetime { + use super::*; + type Opq<'a> = impl Sized + 'a; + fn define<'a: 'b, 'b: 'a>(_: Opq<'a>) { + let _ = None::<<(Opq<'a>, &'b u8) as Indirect>::Ty>; + } } fn main() {} diff --git a/tests/ui/type-alias-impl-trait/defined-in-closure-external-lifetime.rs b/tests/ui/type-alias-impl-trait/defined-in-closure-external-lifetime.rs new file mode 100644 index 0000000000000..9101e4385b3d3 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/defined-in-closure-external-lifetime.rs @@ -0,0 +1,19 @@ +#![feature(type_alias_impl_trait)] + +mod case1 { + type Opaque<'x> = impl Sized + 'x; + fn foo<'s>() -> Opaque<'s> { + let _ = || { let _: Opaque<'s> = (); }; + //~^ ERROR expected generic lifetime parameter, found `'_` + } +} + +mod case2 { + type Opaque<'x> = impl Sized + 'x; + fn foo<'s>() -> Opaque<'s> { + let _ = || -> Opaque<'s> {}; + //~^ ERROR expected generic lifetime parameter, found `'_` + } +} + +fn main() {} diff --git a/tests/ui/type-alias-impl-trait/defined-in-closure-external-lifetime.stderr b/tests/ui/type-alias-impl-trait/defined-in-closure-external-lifetime.stderr new file mode 100644 index 0000000000000..a8fd1f691dd40 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/defined-in-closure-external-lifetime.stderr @@ -0,0 +1,21 @@ +error[E0792]: expected generic lifetime parameter, found `'_` + --> $DIR/defined-in-closure-external-lifetime.rs:6:29 + | +LL | type Opaque<'x> = impl Sized + 'x; + | -- this generic parameter must be used with a generic lifetime parameter +LL | fn foo<'s>() -> Opaque<'s> { +LL | let _ = || { let _: Opaque<'s> = (); }; + | ^^^^^^^^^^ + +error[E0792]: expected generic lifetime parameter, found `'_` + --> $DIR/defined-in-closure-external-lifetime.rs:14:34 + | +LL | type Opaque<'x> = impl Sized + 'x; + | -- this generic parameter must be used with a generic lifetime parameter +LL | fn foo<'s>() -> Opaque<'s> { +LL | let _ = || -> Opaque<'s> {}; + | ^^ + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/type-alias-impl-trait/equal-lifetime-params-not-ok.rs b/tests/ui/type-alias-impl-trait/equal-lifetime-params-not-ok.rs new file mode 100644 index 0000000000000..59ba2694a7643 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/equal-lifetime-params-not-ok.rs @@ -0,0 +1,37 @@ +// issue: #112841 + +#![feature(type_alias_impl_trait)] + +trait Trait<'a, 'b> {} +impl Trait<'_, '_> for T {} + +mod mod1 { + type Opaque<'a, 'b> = impl super::Trait<'a, 'b>; + fn test<'a>() -> Opaque<'a, 'a> {} + //~^ ERROR non-defining opaque type use in defining scope + //~| ERROR non-defining opaque type use in defining scope +} + +mod mod2 { + type Opaque<'a, 'b> = impl super::Trait<'a, 'b>; + fn test<'a: 'b, 'b: 'a>() -> Opaque<'a, 'b> {} + //~^ ERROR non-defining opaque type use in defining scope +} + +mod mod3 { + type Opaque<'a, 'b> = impl super::Trait<'a, 'b>; + fn test<'a: 'b, 'b: 'a>(a: &'a str) -> Opaque<'a, 'b> { a } + //~^ ERROR non-defining opaque type use in defining scope +} + +// This is similar to the previous cases in that 'a is equal to 'static, +// which is is some sense an implicit parameter to `Opaque`. +// For example, given a defining use `Opaque<'a> := &'a ()`, +// it is ambiguous whether `Opaque<'a> := &'a ()` or `Opaque<'a> := &'static ()` +mod mod4 { + type Opaque<'a> = impl super::Trait<'a, 'a>; + fn test<'a: 'static>() -> Opaque<'a> {} + //~^ ERROR expected generic lifetime parameter, found `'static` +} + +fn main() {} diff --git a/tests/ui/type-alias-impl-trait/equal-lifetime-params-not-ok.stderr b/tests/ui/type-alias-impl-trait/equal-lifetime-params-not-ok.stderr new file mode 100644 index 0000000000000..b08bc8b826873 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/equal-lifetime-params-not-ok.stderr @@ -0,0 +1,59 @@ +error: non-defining opaque type use in defining scope + --> $DIR/equal-lifetime-params-not-ok.rs:10:22 + | +LL | fn test<'a>() -> Opaque<'a, 'a> {} + | ^^^^^^^^^^^^^^ generic argument `'a` used twice + | +note: for this opaque type + --> $DIR/equal-lifetime-params-not-ok.rs:9:27 + | +LL | type Opaque<'a, 'b> = impl super::Trait<'a, 'b>; + | ^^^^^^^^^^^^^^^^^^^^^^^^^ + +error: non-defining opaque type use in defining scope + --> $DIR/equal-lifetime-params-not-ok.rs:10:37 + | +LL | fn test<'a>() -> Opaque<'a, 'a> {} + | ^^ + | +note: lifetime used multiple times + --> $DIR/equal-lifetime-params-not-ok.rs:9:17 + | +LL | type Opaque<'a, 'b> = impl super::Trait<'a, 'b>; + | ^^ ^^ + +error: non-defining opaque type use in defining scope + --> $DIR/equal-lifetime-params-not-ok.rs:17:49 + | +LL | fn test<'a: 'b, 'b: 'a>() -> Opaque<'a, 'b> {} + | ^^ + | +note: lifetime used multiple times + --> $DIR/equal-lifetime-params-not-ok.rs:16:17 + | +LL | type Opaque<'a, 'b> = impl super::Trait<'a, 'b>; + | ^^ ^^ + +error: non-defining opaque type use in defining scope + --> $DIR/equal-lifetime-params-not-ok.rs:23:61 + | +LL | fn test<'a: 'b, 'b: 'a>(a: &'a str) -> Opaque<'a, 'b> { a } + | ^ + | +note: lifetime used multiple times + --> $DIR/equal-lifetime-params-not-ok.rs:22:17 + | +LL | type Opaque<'a, 'b> = impl super::Trait<'a, 'b>; + | ^^ ^^ + +error[E0792]: expected generic lifetime parameter, found `'static` + --> $DIR/equal-lifetime-params-not-ok.rs:33:42 + | +LL | type Opaque<'a> = impl super::Trait<'a, 'a>; + | -- cannot use static lifetime; use a bound lifetime instead or remove the lifetime parameter from the opaque type +LL | fn test<'a: 'static>() -> Opaque<'a> {} + | ^^ + +error: aborting due to 5 previous errors + +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/type-alias-impl-trait/equal-lifetime-params-ok.rs b/tests/ui/type-alias-impl-trait/equal-lifetime-params-ok.rs new file mode 100644 index 0000000000000..0ce85a4d6cbe1 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/equal-lifetime-params-ok.rs @@ -0,0 +1,52 @@ +// Normally we do not allow equal lifetimes in opaque type generic args at +// their defining sites. An exception to this rule, however, is when the bounds +// of the opaque type *require* the lifetimes to be equal. +// issue: #113916 +//@ check-pass + +#![feature(type_alias_impl_trait)] +#![feature(impl_trait_in_assoc_type)] + +trait Trait<'a, 'b> {} +impl Trait<'_, '_> for T {} + +mod equal_params { + type Opaque<'a: 'b, 'b: 'a> = impl super::Trait<'a, 'b>; + fn test<'a: 'b, 'b: 'a>() -> Opaque<'a, 'b> { + let _ = None::<&'a &'b &'a ()>; + 0u8 + } +} + +mod equal_static { + type Opaque<'a: 'static> = impl Sized + 'a; + fn test<'a: 'static>() -> Opaque<'a> { + let _ = None::<&'static &'a ()>; + 0u8 + } +} + +mod implied_bounds { + trait Traitor { + type Assoc; + fn define(self) -> Self::Assoc; + } + + impl<'a> Traitor for &'static &'a () { + type Assoc = impl Sized + 'a; + fn define(self) -> Self::Assoc { + let _ = None::<&'static &'a ()>; + 0u8 + } + } + + impl<'a, 'b> Traitor for (&'a &'b (), &'b &'a ()) { + type Assoc = impl Sized + 'a + 'b; + fn define(self) -> Self::Assoc { + let _ = None::<(&'a &'b (), &'b &'a ())>; + 0u8 + } + } +} + +fn main() {} diff --git a/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.basic.stderr b/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.basic.stderr new file mode 100644 index 0000000000000..e5f86c8c19355 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.basic.stderr @@ -0,0 +1,12 @@ +error[E0792]: expected generic lifetime parameter, found `'_` + --> $DIR/generic-not-strictly-equal.rs:33:5 + | +LL | type Opaque<'a> = impl Copy + Captures<'a>; + | -- this generic parameter must be used with a generic lifetime parameter +... +LL | relate(opaque, hidden); // defining use: Opaque<'?1> := u8 + | ^^^^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.member_constraints.stderr b/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.member_constraints.stderr new file mode 100644 index 0000000000000..693af69d6fab9 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.member_constraints.stderr @@ -0,0 +1,15 @@ +error[E0700]: hidden type for `Opaque<'x>` captures lifetime that does not appear in bounds + --> $DIR/generic-not-strictly-equal.rs:33:5 + | +LL | type Opaque<'a> = impl Copy + Captures<'a>; + | ------------------------ opaque type defined here +LL | +LL | fn test<'x>(_: Opaque<'x>) { + | -- hidden type `&'x u8` captures the lifetime `'x` as defined here +... +LL | relate(opaque, hidden); // defining use: Opaque<'?1> := u8 + | ^^^^^^^^^^^^^^^^^^^^^^ + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0700`. diff --git a/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.rs b/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.rs new file mode 100644 index 0000000000000..a059fd3b8227e --- /dev/null +++ b/tests/ui/type-alias-impl-trait/generic-not-strictly-equal.rs @@ -0,0 +1,38 @@ +// `Opaque<'?1> := u8` is not a valid defining use here. +// +// Due to fundamental limitations of the member constraints algorithm, +// we require '?1 to be *equal* to some universal region. +// +// While '?1 is eventually inferred to be equal to 'x because of the constraint '?1: 'x, +// we don't consider them equal in the strict sense because they lack the bidirectional outlives +// constraints ['?1: 'x, 'x: '?1]. In NLL terms, they are not part of the same SCC. +// +// See #113971 for details. + +//@ revisions: basic member_constraints +#![feature(type_alias_impl_trait)] + +trait Captures<'a> {} +impl Captures<'_> for T {} + +fn ensure_outlives<'a, X: 'a>(_: X) {} +fn relate(_: X, _: X) {} + +type Opaque<'a> = impl Copy + Captures<'a>; + +fn test<'x>(_: Opaque<'x>) { + let opaque = None::>; // let's call this lifetime '?1 + + #[cfg(basic)] + let hidden = None::; + + #[cfg(member_constraints)] + let hidden = None::<&'x u8>; + + ensure_outlives::<'x>(opaque); // outlives constraint: '?1: 'x + relate(opaque, hidden); // defining use: Opaque<'?1> := u8 + //[basic]~^ ERROR expected generic lifetime parameter, found `'_` + //[member_constraints]~^^ ERROR captures lifetime that does not appear in bounds +} + +fn main() {} diff --git a/tests/ui/type-alias-impl-trait/hkl_forbidden4.rs b/tests/ui/type-alias-impl-trait/hkl_forbidden4.rs index ef9fe604ea783..3b54fb7ea999f 100644 --- a/tests/ui/type-alias-impl-trait/hkl_forbidden4.rs +++ b/tests/ui/type-alias-impl-trait/hkl_forbidden4.rs @@ -13,6 +13,7 @@ type FutNothing<'a> = impl 'a + Future; async fn operation(_: &mut ()) -> () { //~^ ERROR: concrete type differs from previous call(operation).await + //~^ ERROR: expected generic lifetime parameter, found `'any` } async fn call(_f: F) diff --git a/tests/ui/type-alias-impl-trait/hkl_forbidden4.stderr b/tests/ui/type-alias-impl-trait/hkl_forbidden4.stderr index cd4982b24809a..c41ed0642a46c 100644 --- a/tests/ui/type-alias-impl-trait/hkl_forbidden4.stderr +++ b/tests/ui/type-alias-impl-trait/hkl_forbidden4.stderr @@ -6,20 +6,17 @@ LL | type FutNothing<'a> = impl 'a + Future; | = note: `FutNothing` must be used in combination with a concrete type within the same module -error: concrete type differs from previous defining opaque type use - --> $DIR/hkl_forbidden4.rs:13:1 - | -LL | async fn operation(_: &mut ()) -> () { - | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `FutNothing<'_>`, got `{async fn body of operation()}` - | -note: previous use here +error[E0792]: expected generic lifetime parameter, found `'any` --> $DIR/hkl_forbidden4.rs:15:5 | +LL | async fn operation(_: &mut ()) -> () { + | - this generic parameter must be used with a generic lifetime parameter +LL | LL | call(operation).await | ^^^^^^^^^^^^^^^ error[E0792]: expected generic lifetime parameter, found `'any` - --> $DIR/hkl_forbidden4.rs:21:1 + --> $DIR/hkl_forbidden4.rs:22:1 | LL | type FutNothing<'a> = impl 'a + Future; | -- this generic parameter must be used with a generic lifetime parameter @@ -29,6 +26,18 @@ LL | | LL | | } | |_^ -error: aborting due to 3 previous errors +error: concrete type differs from previous defining opaque type use + --> $DIR/hkl_forbidden4.rs:13:1 + | +LL | async fn operation(_: &mut ()) -> () { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `FutNothing<'_>`, got `{async fn body of operation()}` + | +note: previous use here + --> $DIR/hkl_forbidden4.rs:15:5 + | +LL | call(operation).await + | ^^^^^^^^^^^^^^^ + +error: aborting due to 4 previous errors For more information about this error, try `rustc --explain E0792`. diff --git a/tests/ui/type-alias-impl-trait/lifetime_mismatch.rs b/tests/ui/type-alias-impl-trait/lifetime_mismatch.rs index 9ec585d93f58d..45a55050c4435 100644 --- a/tests/ui/type-alias-impl-trait/lifetime_mismatch.rs +++ b/tests/ui/type-alias-impl-trait/lifetime_mismatch.rs @@ -5,7 +5,6 @@ type Foo<'a> = impl Sized; fn foo<'a, 'b>(x: &'a u32, y: &'b u32) -> (Foo<'a>, Foo<'b>) { (x, y) //~^ ERROR opaque type used twice with different lifetimes - //~| ERROR opaque type used twice with different lifetimes } type Bar<'a, 'b> = impl std::fmt::Debug; @@ -13,9 +12,6 @@ type Bar<'a, 'b> = impl std::fmt::Debug; fn bar<'x, 'y>(i: &'x i32, j: &'y i32) -> (Bar<'x, 'y>, Bar<'y, 'x>) { (i, j) //~^ ERROR opaque type used twice with different lifetimes - //~| ERROR opaque type used twice with different lifetimes - //~| ERROR opaque type used twice with different lifetimes - //~| ERROR opaque type used twice with different lifetimes } fn main() { diff --git a/tests/ui/type-alias-impl-trait/lifetime_mismatch.stderr b/tests/ui/type-alias-impl-trait/lifetime_mismatch.stderr index 7f54f47d27d0c..4f7b0f1740765 100644 --- a/tests/ui/type-alias-impl-trait/lifetime_mismatch.stderr +++ b/tests/ui/type-alias-impl-trait/lifetime_mismatch.stderr @@ -14,53 +14,7 @@ LL | (x, y) | ^^^^^^ error: opaque type used twice with different lifetimes - --> $DIR/lifetime_mismatch.rs:6:5 - | -LL | (x, y) - | ^^^^^^ - | | - | lifetime `'a` used here - | lifetime `'b` previously used here - | -note: if all non-lifetime generic parameters are the same, but the lifetime parameters differ, it is not possible to differentiate the opaque types - --> $DIR/lifetime_mismatch.rs:6:5 - | -LL | (x, y) - | ^^^^^^ - = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` - -error: opaque type used twice with different lifetimes - --> $DIR/lifetime_mismatch.rs:14:5 - | -LL | (i, j) - | ^^^^^^ - | | - | lifetime `'x` used here - | lifetime `'y` previously used here - | -note: if all non-lifetime generic parameters are the same, but the lifetime parameters differ, it is not possible to differentiate the opaque types - --> $DIR/lifetime_mismatch.rs:14:5 - | -LL | (i, j) - | ^^^^^^ - -error: opaque type used twice with different lifetimes - --> $DIR/lifetime_mismatch.rs:14:5 - | -LL | (i, j) - | ^^^^^^ - | | - | lifetime `'y` used here - | lifetime `'x` previously used here - | -note: if all non-lifetime generic parameters are the same, but the lifetime parameters differ, it is not possible to differentiate the opaque types - --> $DIR/lifetime_mismatch.rs:14:5 - | -LL | (i, j) - | ^^^^^^ - -error: opaque type used twice with different lifetimes - --> $DIR/lifetime_mismatch.rs:14:5 + --> $DIR/lifetime_mismatch.rs:13:5 | LL | (i, j) | ^^^^^^ @@ -69,27 +23,10 @@ LL | (i, j) | lifetime `'y` previously used here | note: if all non-lifetime generic parameters are the same, but the lifetime parameters differ, it is not possible to differentiate the opaque types - --> $DIR/lifetime_mismatch.rs:14:5 - | -LL | (i, j) - | ^^^^^^ - = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` - -error: opaque type used twice with different lifetimes - --> $DIR/lifetime_mismatch.rs:14:5 - | -LL | (i, j) - | ^^^^^^ - | | - | lifetime `'y` used here - | lifetime `'x` previously used here - | -note: if all non-lifetime generic parameters are the same, but the lifetime parameters differ, it is not possible to differentiate the opaque types - --> $DIR/lifetime_mismatch.rs:14:5 + --> $DIR/lifetime_mismatch.rs:13:5 | LL | (i, j) | ^^^^^^ - = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` -error: aborting due to 6 previous errors +error: aborting due to 2 previous errors diff --git a/tests/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn-lifetimes.rs b/tests/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn-lifetimes.rs index 5bec38c5e5b2f..580fb58ef8388 100644 --- a/tests/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn-lifetimes.rs +++ b/tests/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn-lifetimes.rs @@ -3,11 +3,8 @@ type Foo<'a, 'b> = impl std::fmt::Debug; fn foo<'x, 'y>(i: &'x i32, j: &'y i32) -> (Foo<'x, 'y>, Foo<'y, 'x>) { - (i, i) + (i, j) //~^ ERROR opaque type used twice with different lifetimes - //~| ERROR opaque type used twice with different lifetimes - //~| ERROR opaque type used twice with different lifetimes - //~| ERROR opaque type used twice with different lifetimes } fn main() {} diff --git a/tests/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn-lifetimes.stderr b/tests/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn-lifetimes.stderr index 0ccb3e2221d83..b2b9e604a6b69 100644 --- a/tests/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn-lifetimes.stderr +++ b/tests/ui/type-alias-impl-trait/multiple-def-uses-in-one-fn-lifetimes.stderr @@ -1,7 +1,7 @@ error: opaque type used twice with different lifetimes --> $DIR/multiple-def-uses-in-one-fn-lifetimes.rs:6:5 | -LL | (i, i) +LL | (i, j) | ^^^^^^ | | | lifetime `'x` used here @@ -10,55 +10,8 @@ LL | (i, i) note: if all non-lifetime generic parameters are the same, but the lifetime parameters differ, it is not possible to differentiate the opaque types --> $DIR/multiple-def-uses-in-one-fn-lifetimes.rs:6:5 | -LL | (i, i) +LL | (i, j) | ^^^^^^ -error: opaque type used twice with different lifetimes - --> $DIR/multiple-def-uses-in-one-fn-lifetimes.rs:6:5 - | -LL | (i, i) - | ^^^^^^ - | | - | lifetime `'y` used here - | lifetime `'x` previously used here - | -note: if all non-lifetime generic parameters are the same, but the lifetime parameters differ, it is not possible to differentiate the opaque types - --> $DIR/multiple-def-uses-in-one-fn-lifetimes.rs:6:5 - | -LL | (i, i) - | ^^^^^^ - -error: opaque type used twice with different lifetimes - --> $DIR/multiple-def-uses-in-one-fn-lifetimes.rs:6:5 - | -LL | (i, i) - | ^^^^^^ - | | - | lifetime `'x` used here - | lifetime `'y` previously used here - | -note: if all non-lifetime generic parameters are the same, but the lifetime parameters differ, it is not possible to differentiate the opaque types - --> $DIR/multiple-def-uses-in-one-fn-lifetimes.rs:6:5 - | -LL | (i, i) - | ^^^^^^ - = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` - -error: opaque type used twice with different lifetimes - --> $DIR/multiple-def-uses-in-one-fn-lifetimes.rs:6:5 - | -LL | (i, i) - | ^^^^^^ - | | - | lifetime `'y` used here - | lifetime `'x` previously used here - | -note: if all non-lifetime generic parameters are the same, but the lifetime parameters differ, it is not possible to differentiate the opaque types - --> $DIR/multiple-def-uses-in-one-fn-lifetimes.rs:6:5 - | -LL | (i, i) - | ^^^^^^ - = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no` - -error: aborting due to 4 previous errors +error: aborting due to 1 previous error diff --git a/tests/ui/type-alias-impl-trait/param_mismatch4.rs b/tests/ui/type-alias-impl-trait/param_mismatch4.rs new file mode 100644 index 0000000000000..e072f3ab8e05b --- /dev/null +++ b/tests/ui/type-alias-impl-trait/param_mismatch4.rs @@ -0,0 +1,16 @@ +//! This test checks that when checking for opaque types that +//! only differ in lifetimes, we handle the case of non-generic +//! regions correctly. +#![feature(type_alias_impl_trait)] + +type Opq<'a> = impl Sized; + +// Two defining uses: Opq<'{empty}> and Opq<'a>. +// This used to ICE. +// issue: #122782 +fn build<'a>() -> Opq<'a> { + let _: Opq<'_> = (); + //~^ ERROR expected generic lifetime parameter, found `'_` +} + +fn main() {} diff --git a/tests/ui/type-alias-impl-trait/param_mismatch4.stderr b/tests/ui/type-alias-impl-trait/param_mismatch4.stderr new file mode 100644 index 0000000000000..d3fdea25a3dc4 --- /dev/null +++ b/tests/ui/type-alias-impl-trait/param_mismatch4.stderr @@ -0,0 +1,12 @@ +error[E0792]: expected generic lifetime parameter, found `'_` + --> $DIR/param_mismatch4.rs:12:12 + | +LL | type Opq<'a> = impl Sized; + | -- this generic parameter must be used with a generic lifetime parameter +... +LL | let _: Opq<'_> = (); + | ^^^^^^^ + +error: aborting due to 1 previous error + +For more information about this error, try `rustc --explain E0792`.