diff options
| -rw-r--r-- | compiler/rustc_hir_analysis/messages.ftl | 3 | ||||
| -rw-r--r-- | compiler/rustc_hir_analysis/src/check/wfcheck.rs | 128 | ||||
| -rw-r--r-- | compiler/rustc_lint/messages.ftl | 3 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/lib.rs | 3 | ||||
| -rw-r--r-- | compiler/rustc_lint/src/redundant_lifetime_args.rs | 177 | ||||
| -rw-r--r-- | tests/ui/generic-associated-types/unsatisfied-item-lifetime-bound.rs | 4 | ||||
| -rw-r--r-- | tests/ui/generic-associated-types/unsatisfied-item-lifetime-bound.stderr | 31 | ||||
| -rw-r--r-- | tests/ui/regions/regions-static-bound.rs | 6 | ||||
| -rw-r--r-- | tests/ui/regions/regions-static-bound.stderr | 46 | ||||
| -rw-r--r-- | tests/ui/regions/transitively-redundant-lifetimes.rs | 2 |
10 files changed, 206 insertions, 197 deletions
diff --git a/compiler/rustc_hir_analysis/messages.ftl b/compiler/rustc_hir_analysis/messages.ftl index e66a834ab9e..86b8b6d6b2b 100644 --- a/compiler/rustc_hir_analysis/messages.ftl +++ b/compiler/rustc_hir_analysis/messages.ftl @@ -355,6 +355,9 @@ hir_analysis_pattern_type_wild_pat = "wildcard patterns are not permitted for pa hir_analysis_placeholder_not_allowed_item_signatures = the placeholder `_` is not allowed within types on item signatures for {$kind} .label = not allowed in type signatures +hir_analysis_redundant_lifetime_args = unnecessary lifetime parameter `{$victim}` + .note = you can use the `{$candidate}` lifetime directly, in place of `{$victim}` + hir_analysis_requires_note = the `{$trait_name}` impl for `{$ty}` requires that `{$error_predicate}` hir_analysis_return_type_notation_equality_bound = diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs index 4fd7c870fc7..cc7c41cb387 100644 --- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs +++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs @@ -8,11 +8,13 @@ use rustc_ast as ast; use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexSet}; use rustc_errors::{codes::*, pluralize, struct_span_code_err, Applicability, ErrorGuaranteed}; use rustc_hir as hir; +use rustc_hir::def::DefKind; use rustc_hir::def_id::{DefId, LocalDefId, LocalModDefId}; use rustc_hir::lang_items::LangItem; use rustc_hir::ItemKind; use rustc_infer::infer::outlives::env::OutlivesEnvironment; use rustc_infer::infer::{self, InferCtxt, TyCtxtInferExt}; +use rustc_macros::LintDiagnostic; use rustc_middle::query::Providers; use rustc_middle::ty::print::with_no_trimmed_paths; use rustc_middle::ty::trait_def::TraitSpecializationKind; @@ -136,6 +138,8 @@ where infcx.implied_bounds_tys_compat(param_env, body_def_id, &assumed_wf_types, false); let outlives_env = OutlivesEnvironment::with_bounds(param_env, implied_bounds); + lint_redundant_lifetimes(tcx, body_def_id, &outlives_env); + let errors = infcx.resolve_regions(&outlives_env); if errors.is_empty() { return Ok(()); @@ -2010,6 +2014,130 @@ fn check_mod_type_wf(tcx: TyCtxt<'_>, module: LocalModDefId) -> Result<(), Error res } +fn lint_redundant_lifetimes<'tcx>( + tcx: TyCtxt<'tcx>, + owner_id: LocalDefId, + outlives_env: &OutlivesEnvironment<'tcx>, +) { + let def_kind = tcx.def_kind(owner_id); + match def_kind { + DefKind::Struct + | DefKind::Union + | DefKind::Enum + | DefKind::Trait + | DefKind::TraitAlias + | DefKind::Fn + | DefKind::Const + | DefKind::Impl { of_trait: false } => { + // Proceed + } + DefKind::AssocFn | DefKind::AssocTy | DefKind::AssocConst => { + let parent_def_id = tcx.local_parent(owner_id); + if matches!(tcx.def_kind(parent_def_id), DefKind::Impl { of_trait: true }) { + // Don't check for redundant lifetimes for trait implementations, + // since the signature is required to be compatible with the trait. + return; + } + } + DefKind::Impl { of_trait: true } + | DefKind::Mod + | DefKind::Variant + | DefKind::TyAlias + | DefKind::ForeignTy + | DefKind::TyParam + | DefKind::ConstParam + | DefKind::Static { .. } + | DefKind::Ctor(_, _) + | DefKind::Macro(_) + | DefKind::ExternCrate + | DefKind::Use + | DefKind::ForeignMod + | DefKind::AnonConst + | DefKind::InlineConst + | DefKind::OpaqueTy + | DefKind::Field + | DefKind::LifetimeParam + | DefKind::GlobalAsm + | DefKind::Closure => return, + } + + // The ordering of this lifetime map is a bit subtle. + // + // Specifically, we want to find a "candidate" lifetime that precedes a "victim" lifetime, + // where we can prove that `'candidate = 'victim`. + // + // `'static` must come first in this list because we can never replace `'static` with + // something else, but if we find some lifetime `'a` where `'a = 'static`, we want to + // suggest replacing `'a` with `'static`. + let mut lifetimes = vec![tcx.lifetimes.re_static]; + lifetimes.extend( + ty::GenericArgs::identity_for_item(tcx, owner_id).iter().filter_map(|arg| arg.as_region()), + ); + // If we are in a function, add its late-bound lifetimes too. + if matches!(def_kind, DefKind::Fn | DefKind::AssocFn) { + for var in tcx.fn_sig(owner_id).instantiate_identity().bound_vars() { + let ty::BoundVariableKind::Region(kind) = var else { continue }; + lifetimes.push(ty::Region::new_late_param(tcx, owner_id.to_def_id(), kind)); + } + } + lifetimes.retain(|candidate| candidate.has_name()); + + // Keep track of lifetimes which have already been replaced with other lifetimes. + // This makes sure that if `'a = 'b = 'c`, we don't say `'c` should be replaced by + // both `'a` and `'b`. + let mut shadowed = FxHashSet::default(); + + for (idx, &candidate) in lifetimes.iter().enumerate() { + // Don't suggest removing a lifetime twice. + if shadowed.contains(&candidate) { + continue; + } + + for &victim in &lifetimes[(idx + 1)..] { + // We only care about lifetimes that are "real", i.e. that have a def-id. + let (ty::ReEarlyParam(ty::EarlyParamRegion { def_id, .. }) + | ty::ReLateParam(ty::LateParamRegion { + bound_region: ty::BoundRegionKind::BrNamed(def_id, _), + .. + })) = victim.kind() + else { + continue; + }; + + // Do not rename lifetimes not local to this item since they'll overlap + // with the lint running on the parent. We still want to consider parent + // lifetimes which make child lifetimes redundant, otherwise we would + // have truncated the `identity_for_item` args above. + if tcx.parent(def_id) != owner_id.to_def_id() { + continue; + } + + // If there are no lifetime errors, then we have proven that `'candidate = 'victim`! + if outlives_env.free_region_map().sub_free_regions(tcx, candidate, victim) + && outlives_env.free_region_map().sub_free_regions(tcx, victim, candidate) + { + shadowed.insert(victim); + tcx.emit_spanned_lint( + rustc_lint_defs::builtin::UNUSED_LIFETIMES, + tcx.local_def_id_to_hir_id(def_id.expect_local()), + tcx.def_span(def_id), + RedundantLifetimeArgsLint { candidate, victim }, + ); + } + } + } +} + +#[derive(LintDiagnostic)] +#[diag(hir_analysis_redundant_lifetime_args)] +#[note] +struct RedundantLifetimeArgsLint<'tcx> { + /// The lifetime we have found to be redundant. + victim: ty::Region<'tcx>, + // The lifetime we can replace the victim with. + candidate: ty::Region<'tcx>, +} + pub fn provide(providers: &mut Providers) { *providers = Providers { check_mod_type_wf, check_well_formed, ..*providers }; } diff --git a/compiler/rustc_lint/messages.ftl b/compiler/rustc_lint/messages.ftl index cc7a87544bc..82b90e1660a 100644 --- a/compiler/rustc_lint/messages.ftl +++ b/compiler/rustc_lint/messages.ftl @@ -534,9 +534,6 @@ lint_reason_must_be_string_literal = reason must be a string literal lint_reason_must_come_last = reason in lint attribute must come last -lint_redundant_lifetime_args = unnecessary lifetime parameter `{$victim}` - .note = you can use the `{$candidate}` lifetime directly, in place of `{$victim}` - lint_redundant_semicolons = unnecessary trailing {$multiple -> [true] semicolons diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs index d13c9549476..31c80c4d75b 100644 --- a/compiler/rustc_lint/src/lib.rs +++ b/compiler/rustc_lint/src/lib.rs @@ -78,7 +78,6 @@ mod opaque_hidden_inferred_bound; mod pass_by_value; mod passes; mod ptr_nulls; -mod redundant_lifetime_args; mod redundant_semicolon; mod reference_casting; mod traits; @@ -114,7 +113,6 @@ use noop_method_call::*; use opaque_hidden_inferred_bound::*; use pass_by_value::*; use ptr_nulls::*; -use redundant_lifetime_args::RedundantLifetimeArgs; use redundant_semicolon::*; use reference_casting::*; use traits::*; @@ -235,7 +233,6 @@ late_lint_methods!( MissingDoc: MissingDoc, AsyncFnInTrait: AsyncFnInTrait, NonLocalDefinitions: NonLocalDefinitions::default(), - RedundantLifetimeArgs: RedundantLifetimeArgs, ] ] ); diff --git a/compiler/rustc_lint/src/redundant_lifetime_args.rs b/compiler/rustc_lint/src/redundant_lifetime_args.rs deleted file mode 100644 index 34ff5e9dfe9..00000000000 --- a/compiler/rustc_lint/src/redundant_lifetime_args.rs +++ /dev/null @@ -1,177 +0,0 @@ -#![allow(rustc::diagnostic_outside_of_impl)] -#![allow(rustc::untranslatable_diagnostic)] - -use rustc_data_structures::fx::FxHashSet; -use rustc_hir as hir; -use rustc_hir::def::DefKind; -use rustc_infer::infer::outlives::env::OutlivesEnvironment; -use rustc_infer::infer::{SubregionOrigin, TyCtxtInferExt}; -use rustc_macros::LintDiagnostic; -use rustc_middle::ty::{self, TyCtxt}; -use rustc_session::lint::builtin::UNUSED_LIFETIMES; -use rustc_span::DUMMY_SP; -use rustc_trait_selection::traits::{outlives_bounds::InferCtxtExt, ObligationCtxt}; - -use crate::{LateContext, LateLintPass}; - -declare_lint_pass!(RedundantLifetimeArgs => []); - -impl<'tcx> LateLintPass<'tcx> for RedundantLifetimeArgs { - fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::Item<'tcx>) { - check(cx.tcx, cx.param_env, item.owner_id); - } - - fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::TraitItem<'tcx>) { - check(cx.tcx, cx.param_env, item.owner_id); - } - - fn check_impl_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx hir::ImplItem<'tcx>) { - if cx - .tcx - .hir() - .expect_item(cx.tcx.local_parent(item.owner_id.def_id)) - .expect_impl() - .of_trait - .is_some() - { - // Don't check for redundant lifetimes for trait implementations, - // since the signature is required to be compatible with the trait. - return; - } - - check(cx.tcx, cx.param_env, item.owner_id); - } -} - -fn check<'tcx>(tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>, owner_id: hir::OwnerId) { - let def_kind = tcx.def_kind(owner_id); - match def_kind { - DefKind::Struct - | DefKind::Union - | DefKind::Enum - | DefKind::Trait - | DefKind::TraitAlias - | DefKind::AssocTy - | DefKind::Fn - | DefKind::Const - | DefKind::AssocFn - | DefKind::AssocConst - | DefKind::Impl { of_trait: _ } => { - // Proceed - } - DefKind::Mod - | DefKind::Variant - | DefKind::TyAlias - | DefKind::ForeignTy - | DefKind::TyParam - | DefKind::ConstParam - | DefKind::Static(_) - | DefKind::Ctor(_, _) - | DefKind::Macro(_) - | DefKind::ExternCrate - | DefKind::Use - | DefKind::ForeignMod - | DefKind::AnonConst - | DefKind::InlineConst - | DefKind::OpaqueTy - | DefKind::Field - | DefKind::LifetimeParam - | DefKind::GlobalAsm - | DefKind::Closure => return, - } - - let infcx = &tcx.infer_ctxt().build(); - let ocx = ObligationCtxt::new(infcx); - - // Compute the implied outlives bounds for the item. This ensures that we treat - // a signature with an argument like `&'a &'b ()` as implicitly having `'b: 'a`. - let Ok(assumed_wf_types) = ocx.assumed_wf_types(param_env, owner_id.def_id) else { - return; - }; - let implied_bounds = infcx.implied_bounds_tys(param_env, owner_id.def_id, assumed_wf_types); - let outlives_env = &OutlivesEnvironment::with_bounds(param_env, implied_bounds); - - // The ordering of this lifetime map is a bit subtle. - // - // Specifically, we want to find a "candidate" lifetime that precedes a "victim" lifetime, - // where we can prove that `'candidate = 'victim`. - // - // `'static` must come first in this list because we can never replace `'static` with - // something else, but if we find some lifetime `'a` where `'a = 'static`, we want to - // suggest replacing `'a` with `'static`. - let mut lifetimes = vec![tcx.lifetimes.re_static]; - lifetimes.extend( - ty::GenericArgs::identity_for_item(tcx, owner_id).iter().filter_map(|arg| arg.as_region()), - ); - // If we are in a function, add its late-bound lifetimes too. - if matches!(def_kind, DefKind::Fn | DefKind::AssocFn) { - for var in tcx.fn_sig(owner_id).instantiate_identity().bound_vars() { - let ty::BoundVariableKind::Region(kind) = var else { continue }; - lifetimes.push(ty::Region::new_late_param(tcx, owner_id.to_def_id(), kind)); - } - } - - // Keep track of lifetimes which have already been replaced with other lifetimes. - // This makes sure that if `'a = 'b = 'c`, we don't say `'c` should be replaced by - // both `'a` and `'b`. - let mut shadowed = FxHashSet::default(); - - for (idx, &candidate) in lifetimes.iter().enumerate() { - // Don't suggest removing a lifetime twice. - if shadowed.contains(&candidate) { - continue; - } - - // Can't rename a named lifetime named `'_` without ambiguity. - if !candidate.has_name() { - continue; - } - - for &victim in &lifetimes[(idx + 1)..] { - // We only care about lifetimes that are "real", i.e. that have a def-id. - let (ty::ReEarlyParam(ty::EarlyParamRegion { def_id, .. }) - | ty::ReLateParam(ty::LateParamRegion { - bound_region: ty::BoundRegionKind::BrNamed(def_id, _), - .. - })) = victim.kind() - else { - continue; - }; - - // Do not rename lifetimes not local to this item since they'll overlap - // with the lint running on the parent. We still want to consider parent - // lifetimes which make child lifetimes redundant, otherwise we would - // have truncated the `identity_for_item` args above. - if tcx.parent(def_id) != owner_id.to_def_id() { - continue; - } - - let infcx = infcx.fork(); - - // Require that `'candidate = 'victim` - infcx.sub_regions(SubregionOrigin::RelateRegionParamBound(DUMMY_SP), candidate, victim); - infcx.sub_regions(SubregionOrigin::RelateRegionParamBound(DUMMY_SP), victim, candidate); - - // If there are no lifetime errors, then we have proven that `'candidate = 'victim`! - if infcx.resolve_regions(outlives_env).is_empty() { - shadowed.insert(victim); - tcx.emit_spanned_lint( - UNUSED_LIFETIMES, - tcx.local_def_id_to_hir_id(def_id.expect_local()), - tcx.def_span(def_id), - RedundantLifetimeArgsLint { candidate, victim }, - ); - } - } - } -} - -#[derive(LintDiagnostic)] -#[diag(lint_redundant_lifetime_args)] -#[note] -struct RedundantLifetimeArgsLint<'tcx> { - /// The lifetime we have found to be redundant. - victim: ty::Region<'tcx>, - // The lifetime we can replace the victim with. - candidate: ty::Region<'tcx>, -} diff --git a/tests/ui/generic-associated-types/unsatisfied-item-lifetime-bound.rs b/tests/ui/generic-associated-types/unsatisfied-item-lifetime-bound.rs index 1d427e89c21..381d094d626 100644 --- a/tests/ui/generic-associated-types/unsatisfied-item-lifetime-bound.rs +++ b/tests/ui/generic-associated-types/unsatisfied-item-lifetime-bound.rs @@ -1,5 +1,7 @@ +#![warn(unused_lifetimes)] + pub trait X { - type Y<'a: 'static>; + type Y<'a: 'static>; //~ WARN unnecessary lifetime parameter `'a` } impl X for () { diff --git a/tests/ui/generic-associated-types/unsatisfied-item-lifetime-bound.stderr b/tests/ui/generic-associated-types/unsatisfied-item-lifetime-bound.stderr index cd2422b4f2d..f1a7511c634 100644 --- a/tests/ui/generic-associated-types/unsatisfied-item-lifetime-bound.stderr +++ b/tests/ui/generic-associated-types/unsatisfied-item-lifetime-bound.stderr @@ -1,5 +1,5 @@ error[E0478]: lifetime bound not satisfied - --> $DIR/unsatisfied-item-lifetime-bound.rs:6:18 + --> $DIR/unsatisfied-item-lifetime-bound.rs:8:18 | LL | type Y<'a: 'static>; | ------------------- definition of `Y` from trait @@ -8,7 +8,7 @@ LL | type Y<'a> = &'a (); | ^^^^^^ | note: lifetime parameter instantiated with the lifetime `'a` as defined here - --> $DIR/unsatisfied-item-lifetime-bound.rs:6:12 + --> $DIR/unsatisfied-item-lifetime-bound.rs:8:12 | LL | type Y<'a> = &'a (); | ^^ @@ -19,44 +19,57 @@ LL | type Y<'a> = &'a () where 'a: 'static; | +++++++++++++++++ error[E0478]: lifetime bound not satisfied - --> $DIR/unsatisfied-item-lifetime-bound.rs:11:8 + --> $DIR/unsatisfied-item-lifetime-bound.rs:13:8 | LL | f: <T as X>::Y<'a>, | ^^^^^^^^^^^^^^^ | note: lifetime parameter instantiated with the lifetime `'a` as defined here - --> $DIR/unsatisfied-item-lifetime-bound.rs:10:10 + --> $DIR/unsatisfied-item-lifetime-bound.rs:12:10 | LL | struct B<'a, T: for<'r> X<Y<'r> = &'r ()>> { | ^^ = note: but lifetime parameter must outlive the static lifetime error[E0478]: lifetime bound not satisfied - --> $DIR/unsatisfied-item-lifetime-bound.rs:16:8 + --> $DIR/unsatisfied-item-lifetime-bound.rs:18:8 | LL | f: <T as X>::Y<'a>, | ^^^^^^^^^^^^^^^ | note: lifetime parameter instantiated with the lifetime `'a` as defined here - --> $DIR/unsatisfied-item-lifetime-bound.rs:15:10 + --> $DIR/unsatisfied-item-lifetime-bound.rs:17:10 | LL | struct C<'a, T: X> { | ^^ = note: but lifetime parameter must outlive the static lifetime error[E0478]: lifetime bound not satisfied - --> $DIR/unsatisfied-item-lifetime-bound.rs:21:8 + --> $DIR/unsatisfied-item-lifetime-bound.rs:23:8 | LL | f: <() as X>::Y<'a>, | ^^^^^^^^^^^^^^^^ | note: lifetime parameter instantiated with the lifetime `'a` as defined here - --> $DIR/unsatisfied-item-lifetime-bound.rs:20:10 + --> $DIR/unsatisfied-item-lifetime-bound.rs:22:10 | LL | struct D<'a> { | ^^ = note: but lifetime parameter must outlive the static lifetime -error: aborting due to 4 previous errors +warning: unnecessary lifetime parameter `'a` + --> $DIR/unsatisfied-item-lifetime-bound.rs:4:12 + | +LL | type Y<'a: 'static>; + | ^^ + | + = note: you can use the `'static` lifetime directly, in place of `'a` +note: the lint level is defined here + --> $DIR/unsatisfied-item-lifetime-bound.rs:1:9 + | +LL | #![warn(unused_lifetimes)] + | ^^^^^^^^^^^^^^^^ + +error: aborting due to 4 previous errors; 1 warning emitted For more information about this error, try `rustc --explain E0478`. diff --git a/tests/ui/regions/regions-static-bound.rs b/tests/ui/regions/regions-static-bound.rs index af6425971bd..3849dfa122f 100644 --- a/tests/ui/regions/regions-static-bound.rs +++ b/tests/ui/regions/regions-static-bound.rs @@ -1,6 +1,12 @@ +#![warn(unused_lifetimes)] + fn static_id<'a,'b>(t: &'a ()) -> &'static () where 'a: 'static { t } +//~^ WARN unnecessary lifetime parameter `'a` +//~| WARN lifetime parameter `'b` never used fn static_id_indirect<'a,'b>(t: &'a ()) -> &'static () +//~^ WARN unnecessary lifetime parameter `'a` +//~| WARN unnecessary lifetime parameter `'b` where 'a: 'b, 'b: 'static { t } fn static_id_wrong_way<'a>(t: &'a ()) -> &'static () where 'static: 'a { diff --git a/tests/ui/regions/regions-static-bound.stderr b/tests/ui/regions/regions-static-bound.stderr index f7b48349e4a..4638ca9e350 100644 --- a/tests/ui/regions/regions-static-bound.stderr +++ b/tests/ui/regions/regions-static-bound.stderr @@ -1,5 +1,43 @@ +warning: lifetime parameter `'b` never used + --> $DIR/regions-static-bound.rs:3:17 + | +LL | fn static_id<'a,'b>(t: &'a ()) -> &'static () where 'a: 'static { t } + | -^^ + | | + | help: elide the unused lifetime + | +note: the lint level is defined here + --> $DIR/regions-static-bound.rs:1:9 + | +LL | #![warn(unused_lifetimes)] + | ^^^^^^^^^^^^^^^^ + +warning: unnecessary lifetime parameter `'a` + --> $DIR/regions-static-bound.rs:3:14 + | +LL | fn static_id<'a,'b>(t: &'a ()) -> &'static () where 'a: 'static { t } + | ^^ + | + = note: you can use the `'static` lifetime directly, in place of `'a` + +warning: unnecessary lifetime parameter `'a` + --> $DIR/regions-static-bound.rs:7:23 + | +LL | fn static_id_indirect<'a,'b>(t: &'a ()) -> &'static () + | ^^ + | + = note: you can use the `'static` lifetime directly, in place of `'a` + +warning: unnecessary lifetime parameter `'b` + --> $DIR/regions-static-bound.rs:7:26 + | +LL | fn static_id_indirect<'a,'b>(t: &'a ()) -> &'static () + | ^^ + | + = note: you can use the `'static` lifetime directly, in place of `'b` + error: lifetime may not live long enough - --> $DIR/regions-static-bound.rs:7:5 + --> $DIR/regions-static-bound.rs:13:5 | LL | fn static_id_wrong_way<'a>(t: &'a ()) -> &'static () where 'static: 'a { | -- lifetime `'a` defined here @@ -7,7 +45,7 @@ LL | t | ^ returning this value requires that `'a` must outlive `'static` error[E0521]: borrowed data escapes outside of function - --> $DIR/regions-static-bound.rs:12:5 + --> $DIR/regions-static-bound.rs:18:5 | LL | fn error(u: &(), v: &()) { | - - let's call the lifetime of this reference `'1` @@ -20,7 +58,7 @@ LL | static_id(&u); | argument requires that `'1` must outlive `'static` error[E0521]: borrowed data escapes outside of function - --> $DIR/regions-static-bound.rs:14:5 + --> $DIR/regions-static-bound.rs:20:5 | LL | fn error(u: &(), v: &()) { | - - let's call the lifetime of this reference `'2` @@ -33,6 +71,6 @@ LL | static_id_indirect(&v); | `v` escapes the function body here | argument requires that `'2` must outlive `'static` -error: aborting due to 3 previous errors +error: aborting due to 3 previous errors; 4 warnings emitted For more information about this error, try `rustc --explain E0521`. diff --git a/tests/ui/regions/transitively-redundant-lifetimes.rs b/tests/ui/regions/transitively-redundant-lifetimes.rs index 3baf2a88abb..af1195fe94f 100644 --- a/tests/ui/regions/transitively-redundant-lifetimes.rs +++ b/tests/ui/regions/transitively-redundant-lifetimes.rs @@ -13,4 +13,6 @@ impl<'a> Bar<'a> { fn d<'b: 'a>(&'b self) {} //~ ERROR unnecessary lifetime parameter `'b` } +fn ok(x: &'static &()) {} + fn main() {} |