diff --git a/src/librustc_error_codes/error_codes.rs b/src/librustc_error_codes/error_codes.rs index 3fb5e04efc922..99ef226f94aae 100644 --- a/src/librustc_error_codes/error_codes.rs +++ b/src/librustc_error_codes/error_codes.rs @@ -439,6 +439,7 @@ E0752: include_str!("./error_codes/E0752.md"), E0753: include_str!("./error_codes/E0753.md"), E0754: include_str!("./error_codes/E0754.md"), E0758: include_str!("./error_codes/E0758.md"), +E0759: include_str!("./error_codes/E0759.md"), E0760: include_str!("./error_codes/E0760.md"), E0761: include_str!("./error_codes/E0761.md"), E0762: include_str!("./error_codes/E0762.md"), diff --git a/src/librustc_error_codes/error_codes/E0759.md b/src/librustc_error_codes/error_codes/E0759.md new file mode 100644 index 0000000000000..a74759bdf634b --- /dev/null +++ b/src/librustc_error_codes/error_codes/E0759.md @@ -0,0 +1,67 @@ +A `'static` requirement in a return type involving a trait is not fulfilled. + +Erroneous code examples: + +```compile_fail,E0759 +use std::fmt::Debug; + +fn foo(x: &i32) -> impl Debug { + x +} +``` + +```compile_fail,E0759 +# use std::fmt::Debug; +fn bar(x: &i32) -> Box { + Box::new(x) +} +``` + +These examples have the same semantics as the following: + +```compile_fail,E0759 +# use std::fmt::Debug; +fn foo(x: &i32) -> impl Debug + 'static { + x +} +``` + +```compile_fail,E0759 +# use std::fmt::Debug; +fn bar(x: &i32) -> Box { + Box::new(x) +} +``` + +Both [`dyn Trait`] and [`impl Trait`] in return types have a an implicit +`'static` requirement, meaning that the value implementing them that is being +returned has to be either a `'static` borrow or an owned value. + +In order to change the requirement from `'static` to be a lifetime derived from +its arguments, you can add an explicit bound, either to an anonymous lifetime +`'_` or some appropriate named lifetime. + +``` +# use std::fmt::Debug; +fn foo(x: &i32) -> impl Debug + '_ { + x +} +fn bar(x: &i32) -> Box { + Box::new(x) +} +``` + +These are equivalent to the following explicit lifetime annotations: + +``` +# use std::fmt::Debug; +fn foo<'a>(x: &'a i32) -> impl Debug + 'a { + x +} +fn bar<'a>(x: &'a i32) -> Box { + Box::new(x) +} +``` + +[`dyn Trait`]: https://doc.rust-lang.org/book/ch17-02-trait-objects.html#using-trait-objects-that-allow-for-values-of-different-types +[`impl Trait`]: https://doc.rust-lang.org/book/ch10-02-traits.html#returning-types-that-implement-traits diff --git a/src/librustc_infer/infer/error_reporting/mod.rs b/src/librustc_infer/infer/error_reporting/mod.rs index a59a91e3005aa..f7969fe779d33 100644 --- a/src/librustc_infer/infer/error_reporting/mod.rs +++ b/src/librustc_infer/infer/error_reporting/mod.rs @@ -2037,8 +2037,7 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> { self.tcx.sess, var_origin.span(), E0495, - "cannot infer an appropriate lifetime{} \ - due to conflicting requirements", + "cannot infer an appropriate lifetime{} due to conflicting requirements", var_description ) } diff --git a/src/librustc_infer/infer/error_reporting/nice_region_error/static_impl_trait.rs b/src/librustc_infer/infer/error_reporting/nice_region_error/static_impl_trait.rs index f4c86ddae604e..853a414290704 100644 --- a/src/librustc_infer/infer/error_reporting/nice_region_error/static_impl_trait.rs +++ b/src/librustc_infer/infer/error_reporting/nice_region_error/static_impl_trait.rs @@ -1,14 +1,15 @@ //! Error Reporting for static impl Traits. -use crate::infer::error_reporting::msg_span_from_free_region; use crate::infer::error_reporting::nice_region_error::NiceRegionError; use crate::infer::lexical_region_resolve::RegionResolutionError; -use rustc_errors::{Applicability, ErrorReported}; +use rustc_errors::{struct_span_err, Applicability, ErrorReported}; +use rustc_hir::{GenericBound, ItemKind, Lifetime, LifetimeName, TyKind}; use rustc_middle::ty::RegionKind; impl<'a, 'tcx> NiceRegionError<'a, 'tcx> { /// Print the error message for lifetime errors when the return type is a static impl Trait. pub(super) fn try_report_static_impl_trait(&self) -> Option { + debug!("try_report_static_impl_trait(error={:?})", self.error); if let Some(ref error) = self.error { if let RegionResolutionError::SubSupConflict( _, @@ -17,18 +18,36 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> { sub_r, sup_origin, sup_r, - ) = error.clone() + ) = error { + debug!( + "try_report_static_impl_trait(var={:?}, sub={:?} {:?} sup={:?} {:?})", + var_origin, sub_origin, sub_r, sup_origin, sup_r + ); let anon_reg_sup = self.tcx().is_suitable_region(sup_r)?; - let (fn_return_span, is_dyn) = - self.tcx().return_type_impl_or_dyn_trait(anon_reg_sup.def_id)?; - if sub_r == &RegionKind::ReStatic { + debug!("try_report_static_impl_trait: anon_reg_sup={:?}", anon_reg_sup); + let fn_return = self.tcx().return_type_impl_or_dyn_trait(anon_reg_sup.def_id)?; + debug!("try_report_static_impl_trait: fn_return={:?}", fn_return); + if **sub_r == RegionKind::ReStatic { let sp = var_origin.span(); let return_sp = sub_origin.span(); - let mut err = - self.tcx().sess.struct_span_err(sp, "cannot infer an appropriate lifetime"); let param_info = self.find_param_with_region(sup_r, sub_r)?; - err.span_label(param_info.param_ty_span, "data with this lifetime..."); + let (lifetime_name, lifetime) = if sup_r.has_name() { + (sup_r.to_string(), format!("lifetime `{}`", sup_r)) + } else { + ("'_".to_owned(), "an anonymous lifetime `'_`".to_string()) + }; + let mut err = struct_span_err!( + self.tcx().sess, + sp, + E0759, + "cannot infer an appropriate lifetime" + ); + err.span_label( + param_info.param_ty_span, + &format!("this data with {}...", lifetime), + ); + debug!("try_report_static_impl_trait: param_info={:?}", param_info); // We try to make the output have fewer overlapping spans if possible. if (sp == sup_origin.span() || !return_sp.overlaps(sup_origin.span())) @@ -38,41 +57,146 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> { // Customize the spans and labels depending on their relative order so // that split sentences flow correctly. - if sup_origin.span().shrink_to_hi() <= return_sp.shrink_to_lo() { - err.span_label(sup_origin.span(), "...is captured here..."); - err.span_label(return_sp, "...and required to be `'static` by this"); + if sup_origin.span().overlaps(return_sp) && sp == sup_origin.span() { + // Avoid the following: + // + // error: cannot infer an appropriate lifetime + // --> $DIR/must_outlive_least_region_or_bound.rs:18:50 + // | + // LL | fn foo(x: &i32) -> Box { Box::new(x) } + // | ---- ---------^- + // + // and instead show: + // + // error: cannot infer an appropriate lifetime + // --> $DIR/must_outlive_least_region_or_bound.rs:18:50 + // | + // LL | fn foo(x: &i32) -> Box { Box::new(x) } + // | ---- ^ + err.span_label( + sup_origin.span(), + "...is captured here, requiring it to live as long as `'static`", + ); } else { - err.span_label(return_sp, "...is required to be `'static` by this..."); - err.span_label(sup_origin.span(), "...and is captured here"); + err.span_label(sup_origin.span(), "...is captured here..."); + if return_sp < sup_origin.span() { + err.span_note( + return_sp, + "...and is required to live as long as `'static` here", + ); + } else { + err.span_label( + return_sp, + "...and is required to live as long as `'static` here", + ); + } } } else { err.span_label( return_sp, - "...is captured and required to be `'static` here", + "...is captured and required to live as long as `'static` here", ); } - let (lifetime, _) = msg_span_from_free_region(self.tcx(), sup_r); - - let lifetime_name = - if sup_r.has_name() { sup_r.to_string() } else { "'_".to_owned() }; // only apply this suggestion onto functions with // explicit non-desugar'able return. - if fn_return_span.desugaring_kind().is_none() { - let msg = format!( - "to permit non-static references in {} `{} Trait` value, you can add \ - an explicit bound for {}", - if is_dyn { "a" } else { "an" }, - if is_dyn { "dyn" } else { "impl" }, - lifetime, - ); + if fn_return.span.desugaring_kind().is_none() { // FIXME: account for the need of parens in `&(dyn Trait + '_)` - err.span_suggestion_verbose( - fn_return_span.shrink_to_hi(), - &msg, - format!(" + {}", lifetime_name), - Applicability::MaybeIncorrect, - ); + + let consider = "consider changing the"; + let declare = "to declare that the"; + let arg = match param_info.param.pat.simple_ident() { + Some(simple_ident) => format!("argument `{}`", simple_ident), + None => "the argument".to_string(), + }; + let explicit = + format!("you can add an explicit `{}` lifetime bound", lifetime_name); + let explicit_static = + format!("explicit `'static` bound to the lifetime of {}", arg); + let captures = format!("captures data from {}", arg); + let add_static_bound = + "alternatively, add an explicit `'static` bound to this reference"; + let plus_lt = format!(" + {}", lifetime_name); + match fn_return.kind { + TyKind::Def(item_id, _) => { + let item = self.tcx().hir().item(item_id.id); + let opaque = if let ItemKind::OpaqueTy(opaque) = &item.kind { + opaque + } else { + err.emit(); + return Some(ErrorReported); + }; + + if let Some(span) = opaque + .bounds + .iter() + .filter_map(|arg| match arg { + GenericBound::Outlives(Lifetime { + name: LifetimeName::Static, + span, + .. + }) => Some(*span), + _ => None, + }) + .next() + { + err.span_suggestion_verbose( + span, + &format!("{} `impl Trait`'s {}", consider, explicit_static), + lifetime_name, + Applicability::MaybeIncorrect, + ); + err.span_suggestion_verbose( + param_info.param_ty_span, + add_static_bound, + param_info.param_ty.to_string(), + Applicability::MaybeIncorrect, + ); + } else { + err.span_suggestion_verbose( + fn_return.span.shrink_to_hi(), + &format!( + "{declare} `impl Trait` {captures}, {explicit}", + declare = declare, + captures = captures, + explicit = explicit, + ), + plus_lt, + Applicability::MaybeIncorrect, + ); + }; + } + TyKind::TraitObject(_, lt) => match lt.name { + LifetimeName::ImplicitObjectLifetimeDefault => { + err.span_suggestion_verbose( + fn_return.span.shrink_to_hi(), + &format!( + "{declare} trait object {captures}, {explicit}", + declare = declare, + captures = captures, + explicit = explicit, + ), + plus_lt, + Applicability::MaybeIncorrect, + ); + } + _ => { + err.span_suggestion_verbose( + lt.span, + &format!("{} trait object's {}", consider, explicit_static), + lifetime_name, + Applicability::MaybeIncorrect, + ); + err.span_suggestion_verbose( + param_info.param_ty_span, + add_static_bound, + param_info.param_ty.to_string(), + Applicability::MaybeIncorrect, + ); + } + }, + _ => {} + } } err.emit(); return Some(ErrorReported); diff --git a/src/librustc_middle/ty/context.rs b/src/librustc_middle/ty/context.rs index d5be3508d2d80..4770993d9cb07 100644 --- a/src/librustc_middle/ty/context.rs +++ b/src/librustc_middle/ty/context.rs @@ -1383,7 +1383,10 @@ impl<'tcx> TyCtxt<'tcx> { }) } - pub fn return_type_impl_or_dyn_trait(&self, scope_def_id: DefId) -> Option<(Span, bool)> { + pub fn return_type_impl_or_dyn_trait( + &self, + scope_def_id: DefId, + ) -> Option<&'tcx hir::Ty<'tcx>> { let hir_id = self.hir().as_local_hir_id(scope_def_id.expect_local()); let hir_output = match self.hir().get(hir_id) { Node::Item(hir::Item { @@ -1429,15 +1432,17 @@ impl<'tcx> TyCtxt<'tcx> { let output = self.erase_late_bound_regions(&sig.output()); if output.is_impl_trait() { let fn_decl = self.hir().fn_decl_by_hir_id(hir_id).unwrap(); - Some((fn_decl.output.span(), false)) + if let hir::FnRetTy::Return(ty) = fn_decl.output { + return Some(ty); + } } else { let mut v = TraitObjectVisitor(vec![]); rustc_hir::intravisit::walk_ty(&mut v, hir_output); if v.0.len() == 1 { - return Some((v.0[0], true)); + return Some(v.0[0]); } - None } + None } _ => None, } diff --git a/src/librustc_middle/ty/diagnostics.rs b/src/librustc_middle/ty/diagnostics.rs index 2e9aa724ac5af..a2812e117ed39 100644 --- a/src/librustc_middle/ty/diagnostics.rs +++ b/src/librustc_middle/ty/diagnostics.rs @@ -236,21 +236,24 @@ pub fn suggest_constraining_type_param( } } -pub struct TraitObjectVisitor(pub Vec); -impl<'v> hir::intravisit::Visitor<'v> for TraitObjectVisitor { +pub struct TraitObjectVisitor<'tcx>(pub Vec<&'tcx hir::Ty<'tcx>>); +impl<'v> hir::intravisit::Visitor<'v> for TraitObjectVisitor<'v> { type Map = rustc_hir::intravisit::ErasedMap<'v>; fn nested_visit_map(&mut self) -> hir::intravisit::NestedVisitorMap { hir::intravisit::NestedVisitorMap::None } - fn visit_ty(&mut self, ty: &hir::Ty<'_>) { + fn visit_ty(&mut self, ty: &'v hir::Ty<'v>) { if let hir::TyKind::TraitObject( _, - hir::Lifetime { name: hir::LifetimeName::ImplicitObjectLifetimeDefault, .. }, + hir::Lifetime { + name: hir::LifetimeName::ImplicitObjectLifetimeDefault | hir::LifetimeName::Static, + .. + }, ) = ty.kind { - self.0.push(ty.span); + self.0.push(ty); } } } diff --git a/src/test/ui/async-await/issues/issue-62097.stderr b/src/test/ui/async-await/issues/issue-62097.stderr index af8fc2cd2ab45..0f58b158904db 100644 --- a/src/test/ui/async-await/issues/issue-62097.stderr +++ b/src/test/ui/async-await/issues/issue-62097.stderr @@ -1,13 +1,14 @@ -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/issue-62097.rs:12:31 | LL | pub async fn run_dummy_fn(&self) { | ^^^^^ | | - | data with this lifetime... + | this data with an anonymous lifetime `'_`... | ...is captured here... LL | foo(|| self.bar()).await; - | --- ...and required to be `'static` by this + | --- ...and is required to live as long as `'static` here error: aborting due to previous error +For more information about this error, try `rustc --explain E0759`. diff --git a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.nll.stderr b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.nll.stderr index 1806d2607a3ac..ca9ca8a9debe2 100644 --- a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.nll.stderr +++ b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.nll.stderr @@ -26,7 +26,34 @@ LL | fn explicit<'a>(x: &'a i32) -> impl Copy + 'a { x } | ^^^^^^^^^^^^^^ error: lifetime may not live long enough - --> $DIR/must_outlive_least_region_or_bound.rs:12:69 + --> $DIR/must_outlive_least_region_or_bound.rs:9:46 + | +LL | fn elided2(x: &i32) -> impl Copy + 'static { x } + | - ^ returning this value requires that `'1` must outlive `'static` + | | + | let's call the lifetime of this reference `'1` + | + = help: consider replacing `'1` with `'static` + +error: lifetime may not live long enough + --> $DIR/must_outlive_least_region_or_bound.rs:12:55 + | +LL | fn explicit2<'a>(x: &'a i32) -> impl Copy + 'static { x } + | -- lifetime `'a` defined here ^ returning this value requires that `'a` must outlive `'static` + | + = help: consider replacing `'a` with `'static` + = help: consider replacing `'a` with `'static` + +error[E0621]: explicit lifetime required in the type of `x` + --> $DIR/must_outlive_least_region_or_bound.rs:15:41 + | +LL | fn foo<'a>(x: &i32) -> impl Copy + 'a { x } + | ---- ^ lifetime `'a` required + | | + | help: add explicit lifetime `'a` to the type of `x`: `&'a i32` + +error: lifetime may not live long enough + --> $DIR/must_outlive_least_region_or_bound.rs:33:69 | LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x } | -- lifetime `'a` defined here ^ returning this value requires that `'a` must outlive `'static` @@ -35,7 +62,7 @@ LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x } = help: consider replacing `'a` with `'static` error: lifetime may not live long enough - --> $DIR/must_outlive_least_region_or_bound.rs:17:61 + --> $DIR/must_outlive_least_region_or_bound.rs:38:61 | LL | fn move_lifetime_into_fn<'a, 'b>(x: &'a u32, y: &'b u32) -> impl Fn(&'a u32) { | -- -- lifetime `'b` defined here ^^^^^^^^^^^^^^^^ opaque type requires that `'b` must outlive `'a` @@ -45,13 +72,14 @@ LL | fn move_lifetime_into_fn<'a, 'b>(x: &'a u32, y: &'b u32) -> impl Fn(&'a u32 = help: consider adding the following bound: `'b: 'a` error[E0310]: the parameter type `T` may not live long enough - --> $DIR/must_outlive_least_region_or_bound.rs:22:51 + --> $DIR/must_outlive_least_region_or_bound.rs:43:51 | LL | fn ty_param_wont_outlive_static(x: T) -> impl Debug + 'static { | ^^^^^^^^^^^^^^^^^^^^ | = help: consider adding an explicit lifetime bound `T: 'static`... -error: aborting due to 5 previous errors +error: aborting due to 8 previous errors -For more information about this error, try `rustc --explain E0310`. +Some errors have detailed explanations: E0310, E0621. +For more information about an error, try `rustc --explain E0310`. diff --git a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs index 00f3490991b52..837244b022721 100644 --- a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs +++ b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs @@ -6,6 +6,27 @@ fn elided(x: &i32) -> impl Copy { x } fn explicit<'a>(x: &'a i32) -> impl Copy { x } //~^ ERROR cannot infer an appropriate lifetime +fn elided2(x: &i32) -> impl Copy + 'static { x } +//~^ ERROR cannot infer an appropriate lifetime + +fn explicit2<'a>(x: &'a i32) -> impl Copy + 'static { x } +//~^ ERROR cannot infer an appropriate lifetime + +fn foo<'a>(x: &i32) -> impl Copy + 'a { x } +//~^ ERROR explicit lifetime required in the type of `x` + +fn elided3(x: &i32) -> Box { Box::new(x) } +//~^ ERROR cannot infer an appropriate lifetime + +fn explicit3<'a>(x: &'a i32) -> Box { Box::new(x) } +//~^ ERROR cannot infer an appropriate lifetime + +fn elided4(x: &i32) -> Box { Box::new(x) } +//~^ ERROR cannot infer an appropriate lifetime + +fn explicit4<'a>(x: &'a i32) -> Box { Box::new(x) } +//~^ ERROR cannot infer an appropriate lifetime + trait LifetimeTrait<'a> {} impl<'a> LifetimeTrait<'a> for &'a i32 {} diff --git a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr index d7dae6a08a7b9..e1fa4f02b6fcf 100644 --- a/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr +++ b/src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr @@ -1,47 +1,113 @@ -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/must_outlive_least_region_or_bound.rs:3:35 | LL | fn elided(x: &i32) -> impl Copy { x } - | ---- --------- ^ ...and is captured here - | | | - | | ...is required to be `'static` by this... - | data with this lifetime... + | ---- ^ ...is captured here... + | | + | this data with an anonymous lifetime `'_`... | -help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the function body at 3:1 +note: ...and is required to live as long as `'static` here + --> $DIR/must_outlive_least_region_or_bound.rs:3:23 + | +LL | fn elided(x: &i32) -> impl Copy { x } + | ^^^^^^^^^ +help: to declare that the `impl Trait` captures data from argument `x`, you can add an explicit `'_` lifetime bound | LL | fn elided(x: &i32) -> impl Copy + '_ { x } | ^^^^ -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/must_outlive_least_region_or_bound.rs:6:44 | LL | fn explicit<'a>(x: &'a i32) -> impl Copy { x } - | ------- --------- ^ ...and is captured here - | | | - | | ...is required to be `'static` by this... - | data with this lifetime... + | ------- ^ ...is captured here... + | | + | this data with lifetime `'a`... | -help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the lifetime `'a` as defined on the function body at 6:13 +note: ...and is required to live as long as `'static` here + --> $DIR/must_outlive_least_region_or_bound.rs:6:32 + | +LL | fn explicit<'a>(x: &'a i32) -> impl Copy { x } + | ^^^^^^^^^ +help: to declare that the `impl Trait` captures data from argument `x`, you can add an explicit `'a` lifetime bound | LL | fn explicit<'a>(x: &'a i32) -> impl Copy + 'a { x } | ^^^^ -error: cannot infer an appropriate lifetime - --> $DIR/must_outlive_least_region_or_bound.rs:12:69 +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/must_outlive_least_region_or_bound.rs:9:46 + | +LL | fn elided2(x: &i32) -> impl Copy + 'static { x } + | ---- ^ ...is captured here... + | | + | this data with an anonymous lifetime `'_`... + | +note: ...and is required to live as long as `'static` here + --> $DIR/must_outlive_least_region_or_bound.rs:9:24 + | +LL | fn elided2(x: &i32) -> impl Copy + 'static { x } + | ^^^^^^^^^^^^^^^^^^^ +help: consider changing the `impl Trait`'s explicit `'static` bound to the lifetime of argument `x` + | +LL | fn elided2(x: &i32) -> impl Copy + '_ { x } + | ^^ +help: alternatively, add an explicit `'static` bound to this reference + | +LL | fn elided2(x: &'static i32) -> impl Copy + 'static { x } + | ^^^^^^^^^^^^ + +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/must_outlive_least_region_or_bound.rs:12:55 + | +LL | fn explicit2<'a>(x: &'a i32) -> impl Copy + 'static { x } + | ------- ^ ...is captured here... + | | + | this data with lifetime `'a`... + | +note: ...and is required to live as long as `'static` here + --> $DIR/must_outlive_least_region_or_bound.rs:12:33 + | +LL | fn explicit2<'a>(x: &'a i32) -> impl Copy + 'static { x } + | ^^^^^^^^^^^^^^^^^^^ +help: consider changing the `impl Trait`'s explicit `'static` bound to the lifetime of argument `x` + | +LL | fn explicit2<'a>(x: &'a i32) -> impl Copy + 'a { x } + | ^^ +help: alternatively, add an explicit `'static` bound to this reference + | +LL | fn explicit2<'a>(x: &'static i32) -> impl Copy + 'static { x } + | ^^^^^^^^^^^^ + +error[E0621]: explicit lifetime required in the type of `x` + --> $DIR/must_outlive_least_region_or_bound.rs:15:24 + | +LL | fn foo<'a>(x: &i32) -> impl Copy + 'a { x } + | ---- ^^^^^^^^^^^^^^ lifetime `'a` required + | | + | help: add explicit lifetime `'a` to the type of `x`: `&'a i32` + +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/must_outlive_least_region_or_bound.rs:33:69 | LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x } - | ------- -------------------------------- ^ ...and is captured here - | | | - | | ...is required to be `'static` by this... - | data with this lifetime... + | ------- this data with lifetime `'a`... ^ ...is captured here... | -help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the lifetime `'a` as defined on the function body at 12:15 +note: ...and is required to live as long as `'static` here + --> $DIR/must_outlive_least_region_or_bound.rs:33:34 + | +LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static { x } + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ +help: consider changing the `impl Trait`'s explicit `'static` bound to the lifetime of argument `x` | -LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'static + 'a { x } - | ^^^^ +LL | fn with_bound<'a>(x: &'a i32) -> impl LifetimeTrait<'a> + 'a { x } + | ^^ +help: alternatively, add an explicit `'static` bound to this reference + | +LL | fn with_bound<'a>(x: &'static i32) -> impl LifetimeTrait<'a> + 'static { x } + | ^^^^^^^^^^^^ error[E0623]: lifetime mismatch - --> $DIR/must_outlive_least_region_or_bound.rs:17:61 + --> $DIR/must_outlive_least_region_or_bound.rs:38:61 | LL | fn move_lifetime_into_fn<'a, 'b>(x: &'a u32, y: &'b u32) -> impl Fn(&'a u32) { | ------- ^^^^^^^^^^^^^^^^ @@ -50,14 +116,72 @@ LL | fn move_lifetime_into_fn<'a, 'b>(x: &'a u32, y: &'b u32) -> impl Fn(&'a u32 | this parameter and the return type are declared with different lifetimes... error[E0310]: the parameter type `T` may not live long enough - --> $DIR/must_outlive_least_region_or_bound.rs:22:51 + --> $DIR/must_outlive_least_region_or_bound.rs:43:51 | LL | fn ty_param_wont_outlive_static(x: T) -> impl Debug + 'static { | -- ^^^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds | | | help: consider adding an explicit lifetime bound...: `T: 'static +` -error: aborting due to 5 previous errors +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/must_outlive_least_region_or_bound.rs:18:50 + | +LL | fn elided3(x: &i32) -> Box { Box::new(x) } + | ---- ^ ...is captured here, requiring it to live as long as `'static` + | | + | this data with an anonymous lifetime `'_`... + | +help: to declare that the trait object captures data from argument `x`, you can add an explicit `'_` lifetime bound + | +LL | fn elided3(x: &i32) -> Box { Box::new(x) } + | ^^^^ + +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/must_outlive_least_region_or_bound.rs:21:59 + | +LL | fn explicit3<'a>(x: &'a i32) -> Box { Box::new(x) } + | ------- ^ ...is captured here, requiring it to live as long as `'static` + | | + | this data with lifetime `'a`... + | +help: to declare that the trait object captures data from argument `x`, you can add an explicit `'a` lifetime bound + | +LL | fn explicit3<'a>(x: &'a i32) -> Box { Box::new(x) } + | ^^^^ + +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/must_outlive_least_region_or_bound.rs:24:60 + | +LL | fn elided4(x: &i32) -> Box { Box::new(x) } + | ---- ^ ...is captured here, requiring it to live as long as `'static` + | | + | this data with an anonymous lifetime `'_`... + | +help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `x` + | +LL | fn elided4(x: &i32) -> Box { Box::new(x) } + | ^^ +help: alternatively, add an explicit `'static` bound to this reference + | +LL | fn elided4(x: &'static i32) -> Box { Box::new(x) } + | ^^^^^^^^^^^^ + +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/must_outlive_least_region_or_bound.rs:27:69 + | +LL | fn explicit4<'a>(x: &'a i32) -> Box { Box::new(x) } + | ------- this data with lifetime `'a`... ^ ...is captured here, requiring it to live as long as `'static` + | +help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `x` + | +LL | fn explicit4<'a>(x: &'a i32) -> Box { Box::new(x) } + | ^^ +help: alternatively, add an explicit `'static` bound to this reference + | +LL | fn explicit4<'a>(x: &'static i32) -> Box { Box::new(x) } + | ^^^^^^^^^^^^ + +error: aborting due to 12 previous errors -Some errors have detailed explanations: E0310, E0623. +Some errors have detailed explanations: E0310, E0621, E0623, E0759. For more information about an error, try `rustc --explain E0310`. diff --git a/src/test/ui/impl-trait/static-return-lifetime-infered.stderr b/src/test/ui/impl-trait/static-return-lifetime-infered.stderr index 1c3a5979ee55b..df0db6e4fc6df 100644 --- a/src/test/ui/impl-trait/static-return-lifetime-infered.stderr +++ b/src/test/ui/impl-trait/static-return-lifetime-infered.stderr @@ -1,36 +1,43 @@ -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/static-return-lifetime-infered.rs:7:16 | LL | fn iter_values_anon(&self) -> impl Iterator { - | ----- ----------------------- ...is required to be `'static` by this... - | | - | data with this lifetime... + | ----- this data with an anonymous lifetime `'_`... LL | self.x.iter().map(|a| a.0) | ------ ^^^^ | | - | ...and is captured here + | ...is captured here... | -help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the method body at 6:5 +note: ...and is required to live as long as `'static` here + --> $DIR/static-return-lifetime-infered.rs:6:35 + | +LL | fn iter_values_anon(&self) -> impl Iterator { + | ^^^^^^^^^^^^^^^^^^^^^^^ +help: to declare that the `impl Trait` captures data from argument `self`, you can add an explicit `'_` lifetime bound | LL | fn iter_values_anon(&self) -> impl Iterator + '_ { | ^^^^ -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/static-return-lifetime-infered.rs:11:16 | LL | fn iter_values<'a>(&'a self) -> impl Iterator { - | -------- ----------------------- ...is required to be `'static` by this... - | | - | data with this lifetime... + | -------- this data with lifetime `'a`... LL | self.x.iter().map(|a| a.0) | ------ ^^^^ | | - | ...and is captured here + | ...is captured here... | -help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the lifetime `'a` as defined on the method body at 10:20 +note: ...and is required to live as long as `'static` here + --> $DIR/static-return-lifetime-infered.rs:10:37 + | +LL | fn iter_values<'a>(&'a self) -> impl Iterator { + | ^^^^^^^^^^^^^^^^^^^^^^^ +help: to declare that the `impl Trait` captures data from argument `self`, you can add an explicit `'a` lifetime bound | LL | fn iter_values<'a>(&'a self) -> impl Iterator + 'a { | ^^^^ error: aborting due to 2 previous errors +For more information about this error, try `rustc --explain E0759`. diff --git a/src/test/ui/issues/issue-16922.stderr b/src/test/ui/issues/issue-16922.stderr index 02d33aae023ff..919594fc9af4b 100644 --- a/src/test/ui/issues/issue-16922.stderr +++ b/src/test/ui/issues/issue-16922.stderr @@ -1,18 +1,16 @@ -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/issue-16922.rs:4:14 | LL | fn foo(value: &T) -> Box { - | -- data with this lifetime... + | -- this data with an anonymous lifetime `'_`... LL | Box::new(value) as Box - | ---------^^^^^- - | | | - | | ...and is captured here - | ...is required to be `'static` by this... + | ^^^^^ ...is captured here, requiring it to live as long as `'static` | -help: to permit non-static references in a `dyn Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the function body at 3:1 +help: to declare that the trait object captures data from argument `value`, you can add an explicit `'_` lifetime bound | LL | fn foo(value: &T) -> Box { | ^^^^ error: aborting due to previous error +For more information about this error, try `rustc --explain E0759`. diff --git a/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr b/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr index 70a9bf22b8db3..1b1e0d9610724 100644 --- a/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr +++ b/src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr @@ -1,13 +1,13 @@ -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/object-lifetime-default-from-box-error.rs:18:5 | LL | fn load(ss: &mut SomeStruct) -> Box { - | --------------- data with this lifetime... + | --------------- this data with an anonymous lifetime `'_`... ... LL | ss.r - | ^^^^ ...is captured and required to be `'static` here + | ^^^^ ...is captured and required to live as long as `'static` here | -help: to permit non-static references in a `dyn Trait` value, you can add an explicit bound for the anonymous lifetime #2 defined on the function body at 14:1 +help: to declare that the trait object captures data from argument `ss`, you can add an explicit `'_` lifetime bound | LL | fn load(ss: &mut SomeStruct) -> Box { | ^^^^ @@ -23,4 +23,5 @@ LL | ss.r = b; error: aborting due to 2 previous errors -For more information about this error, try `rustc --explain E0621`. +Some errors have detailed explanations: E0621, E0759. +For more information about an error, try `rustc --explain E0621`. diff --git a/src/test/ui/regions/region-object-lifetime-in-coercion.nll.stderr b/src/test/ui/regions/region-object-lifetime-in-coercion.nll.stderr index bf02ba8eb9199..7e8f78067e08a 100644 --- a/src/test/ui/regions/region-object-lifetime-in-coercion.nll.stderr +++ b/src/test/ui/regions/region-object-lifetime-in-coercion.nll.stderr @@ -1,21 +1,21 @@ -error[E0621]: explicit lifetime required in the type of `v` +error: lifetime may not live long enough --> $DIR/region-object-lifetime-in-coercion.rs:8:12 | LL | fn a(v: &[u8]) -> Box { - | ----- help: add explicit lifetime `'static` to the type of `v`: `&'static [u8]` + | - let's call the lifetime of this reference `'1` LL | let x: Box = Box::new(v); - | ^^^^^^^^^^^^^^^^^^^^^^ lifetime `'static` required + | ^^^^^^^^^^^^^^^^^^^^^^ type annotation requires that `'1` must outlive `'static` -error[E0621]: explicit lifetime required in the type of `v` - --> $DIR/region-object-lifetime-in-coercion.rs:14:5 +error: lifetime may not live long enough + --> $DIR/region-object-lifetime-in-coercion.rs:13:5 | LL | fn b(v: &[u8]) -> Box { - | ----- help: add explicit lifetime `'static` to the type of `v`: `&'static [u8]` + | - let's call the lifetime of this reference `'1` LL | Box::new(v) - | ^^^^^^^^^^^ lifetime `'static` required + | ^^^^^^^^^^^ returning this value requires that `'1` must outlive `'static` error: lifetime may not live long enough - --> $DIR/region-object-lifetime-in-coercion.rs:20:5 + --> $DIR/region-object-lifetime-in-coercion.rs:19:5 | LL | fn c(v: &[u8]) -> Box { | - let's call the lifetime of this reference `'1` @@ -24,7 +24,7 @@ LL | Box::new(v) | ^^^^^^^^^^^ returning this value requires that `'1` must outlive `'static` error: lifetime may not live long enough - --> $DIR/region-object-lifetime-in-coercion.rs:24:5 + --> $DIR/region-object-lifetime-in-coercion.rs:23:5 | LL | fn d<'a,'b>(v: &'a [u8]) -> Box { | -- -- lifetime `'b` defined here @@ -37,4 +37,3 @@ LL | Box::new(v) error: aborting due to 4 previous errors -For more information about this error, try `rustc --explain E0621`. diff --git a/src/test/ui/regions/region-object-lifetime-in-coercion.rs b/src/test/ui/regions/region-object-lifetime-in-coercion.rs index d56eaf77b6646..5d199149c39b8 100644 --- a/src/test/ui/regions/region-object-lifetime-in-coercion.rs +++ b/src/test/ui/regions/region-object-lifetime-in-coercion.rs @@ -5,13 +5,12 @@ trait Foo {} impl<'a> Foo for &'a [u8] {} fn a(v: &[u8]) -> Box { - let x: Box = Box::new(v); - //~^ ERROR explicit lifetime required in the type of `v` [E0621] + let x: Box = Box::new(v); //~ ERROR cannot infer an appropriate lifetime x } fn b(v: &[u8]) -> Box { - Box::new(v) //~ ERROR explicit lifetime required in the type of `v` [E0621] + Box::new(v) //~ ERROR cannot infer an appropriate lifetime } fn c(v: &[u8]) -> Box { diff --git a/src/test/ui/regions/region-object-lifetime-in-coercion.stderr b/src/test/ui/regions/region-object-lifetime-in-coercion.stderr index 1462af44cb15a..7f5a3a47976c7 100644 --- a/src/test/ui/regions/region-object-lifetime-in-coercion.stderr +++ b/src/test/ui/regions/region-object-lifetime-in-coercion.stderr @@ -1,61 +1,76 @@ -error[E0621]: explicit lifetime required in the type of `v` - --> $DIR/region-object-lifetime-in-coercion.rs:8:37 +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/region-object-lifetime-in-coercion.rs:8:46 | LL | fn a(v: &[u8]) -> Box { - | ----- help: add explicit lifetime `'static` to the type of `v`: `&'static [u8]` + | ----- this data with an anonymous lifetime `'_`... LL | let x: Box = Box::new(v); - | ^^^^^^^^^^^ lifetime `'static` required + | ^ ...is captured here, requiring it to live as long as `'static` + | +help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v` + | +LL | fn a(v: &[u8]) -> Box { + | ^^ +help: alternatively, add an explicit `'static` bound to this reference + | +LL | fn a(v: &'static [u8]) -> Box { + | ^^^^^^^^^^^^^ -error[E0621]: explicit lifetime required in the type of `v` - --> $DIR/region-object-lifetime-in-coercion.rs:14:5 +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/region-object-lifetime-in-coercion.rs:13:14 | LL | fn b(v: &[u8]) -> Box { - | ----- help: add explicit lifetime `'static` to the type of `v`: `&'static [u8]` + | ----- this data with an anonymous lifetime `'_`... LL | Box::new(v) - | ^^^^^^^^^^^ lifetime `'static` required + | ^ ...is captured here, requiring it to live as long as `'static` + | +help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v` + | +LL | fn b(v: &[u8]) -> Box { + | ^^ +help: alternatively, add an explicit `'static` bound to this reference + | +LL | fn b(v: &'static [u8]) -> Box { + | ^^^^^^^^^^^^^ -error: cannot infer an appropriate lifetime - --> $DIR/region-object-lifetime-in-coercion.rs:20:14 +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/region-object-lifetime-in-coercion.rs:19:14 | LL | fn c(v: &[u8]) -> Box { - | ----- data with this lifetime... + | ----- this data with an anonymous lifetime `'_`... ... LL | Box::new(v) - | ---------^- - | | | - | | ...and is captured here - | ...is required to be `'static` by this... + | ^ ...is captured here, requiring it to live as long as `'static` | -help: to permit non-static references in a `dyn Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the function body at 17:1 +help: to declare that the trait object captures data from argument `v`, you can add an explicit `'_` lifetime bound | LL | fn c(v: &[u8]) -> Box { | ^^^^ error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements - --> $DIR/region-object-lifetime-in-coercion.rs:24:14 + --> $DIR/region-object-lifetime-in-coercion.rs:23:14 | LL | Box::new(v) | ^ | -note: first, the lifetime cannot outlive the lifetime `'a` as defined on the function body at 23:6... - --> $DIR/region-object-lifetime-in-coercion.rs:23:6 +note: first, the lifetime cannot outlive the lifetime `'a` as defined on the function body at 22:6... + --> $DIR/region-object-lifetime-in-coercion.rs:22:6 | LL | fn d<'a,'b>(v: &'a [u8]) -> Box { | ^^ note: ...so that the expression is assignable - --> $DIR/region-object-lifetime-in-coercion.rs:24:14 + --> $DIR/region-object-lifetime-in-coercion.rs:23:14 | LL | Box::new(v) | ^ = note: expected `&[u8]` found `&'a [u8]` -note: but, the lifetime must be valid for the lifetime `'b` as defined on the function body at 23:9... - --> $DIR/region-object-lifetime-in-coercion.rs:23:9 +note: but, the lifetime must be valid for the lifetime `'b` as defined on the function body at 22:9... + --> $DIR/region-object-lifetime-in-coercion.rs:22:9 | LL | fn d<'a,'b>(v: &'a [u8]) -> Box { | ^^ note: ...so that the expression is assignable - --> $DIR/region-object-lifetime-in-coercion.rs:24:5 + --> $DIR/region-object-lifetime-in-coercion.rs:23:5 | LL | Box::new(v) | ^^^^^^^^^^^ @@ -64,5 +79,5 @@ LL | Box::new(v) error: aborting due to 4 previous errors -Some errors have detailed explanations: E0495, E0621. +Some errors have detailed explanations: E0495, E0759. For more information about an error, try `rustc --explain E0495`. diff --git a/src/test/ui/regions/regions-close-object-into-object-2.stderr b/src/test/ui/regions/regions-close-object-into-object-2.stderr index 147f7f3541816..114e4052aae09 100644 --- a/src/test/ui/regions/regions-close-object-into-object-2.stderr +++ b/src/test/ui/regions/regions-close-object-into-object-2.stderr @@ -1,28 +1,20 @@ -error[E0495]: cannot infer an appropriate lifetime for borrow expression due to conflicting requirements +error[E0759]: cannot infer an appropriate lifetime --> $DIR/regions-close-object-into-object-2.rs:10:11 | +LL | fn g<'a, T: 'static>(v: Box + 'a>) -> Box { + | ------------------ this data with lifetime `'a`... LL | box B(&*v) as Box - | ^^^ - | -note: first, the lifetime cannot outlive the lifetime `'a` as defined on the function body at 9:6... - --> $DIR/regions-close-object-into-object-2.rs:9:6 + | ^^^ ...is captured here, requiring it to live as long as `'static` | -LL | fn g<'a, T: 'static>(v: Box + 'a>) -> Box { - | ^^ -note: ...so that the type `(dyn A + 'a)` is not borrowed for too long - --> $DIR/regions-close-object-into-object-2.rs:10:11 +help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v` | -LL | box B(&*v) as Box - | ^^^ - = note: but, the lifetime must be valid for the static lifetime... -note: ...so that the expression is assignable - --> $DIR/regions-close-object-into-object-2.rs:10:5 +LL | fn g<'a, T: 'static>(v: Box + 'a>) -> Box { + | ^^ +help: alternatively, add an explicit `'static` bound to this reference | -LL | box B(&*v) as Box - | ^^^^^^^^^^^^^^^^^^^^^^^^ - = note: expected `std::boxed::Box<(dyn X + 'static)>` - found `std::boxed::Box` +LL | fn g<'a, T: 'static>(v: std::boxed::Box<(dyn A + 'static)>) -> Box { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: aborting due to previous error -For more information about this error, try `rustc --explain E0495`. +For more information about this error, try `rustc --explain E0759`. diff --git a/src/test/ui/regions/regions-close-object-into-object-4.stderr b/src/test/ui/regions/regions-close-object-into-object-4.stderr index 6e7d6152cd09a..850d81940791f 100644 --- a/src/test/ui/regions/regions-close-object-into-object-4.stderr +++ b/src/test/ui/regions/regions-close-object-into-object-4.stderr @@ -1,28 +1,20 @@ -error[E0495]: cannot infer an appropriate lifetime for borrow expression due to conflicting requirements +error[E0759]: cannot infer an appropriate lifetime --> $DIR/regions-close-object-into-object-4.rs:10:11 | +LL | fn i<'a, T, U>(v: Box+'a>) -> Box { + | ---------------- this data with lifetime `'a`... LL | box B(&*v) as Box - | ^^^ - | -note: first, the lifetime cannot outlive the lifetime `'a` as defined on the function body at 9:6... - --> $DIR/regions-close-object-into-object-4.rs:9:6 + | ^^^ ...is captured here, requiring it to live as long as `'static` | -LL | fn i<'a, T, U>(v: Box+'a>) -> Box { - | ^^ -note: ...so that the type `(dyn A + 'a)` is not borrowed for too long - --> $DIR/regions-close-object-into-object-4.rs:10:11 +help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `v` | -LL | box B(&*v) as Box - | ^^^ - = note: but, the lifetime must be valid for the static lifetime... -note: ...so that the expression is assignable - --> $DIR/regions-close-object-into-object-4.rs:10:5 +LL | fn i<'a, T, U>(v: Box+'a>) -> Box { + | ^^ +help: alternatively, add an explicit `'static` bound to this reference | -LL | box B(&*v) as Box - | ^^^^^^^^^^^^^^^^^^^^^^^^ - = note: expected `std::boxed::Box<(dyn X + 'static)>` - found `std::boxed::Box` +LL | fn i<'a, T, U>(v: std::boxed::Box<(dyn A + 'static)>) -> Box { + | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: aborting due to previous error -For more information about this error, try `rustc --explain E0495`. +For more information about this error, try `rustc --explain E0759`. diff --git a/src/test/ui/regions/regions-proc-bound-capture.nll.stderr b/src/test/ui/regions/regions-proc-bound-capture.nll.stderr new file mode 100644 index 0000000000000..75890b8581537 --- /dev/null +++ b/src/test/ui/regions/regions-proc-bound-capture.nll.stderr @@ -0,0 +1,11 @@ +error: lifetime may not live long enough + --> $DIR/regions-proc-bound-capture.rs:9:5 + | +LL | fn static_proc(x: &isize) -> Box (isize) + 'static> { + | - let's call the lifetime of this reference `'1` +LL | // This is illegal, because the region bound on `proc` is 'static. +LL | Box::new(move || { *x }) + | ^^^^^^^^^^^^^^^^^^^^^^^^ returning this value requires that `'1` must outlive `'static` + +error: aborting due to previous error + diff --git a/src/test/ui/regions/regions-proc-bound-capture.rs b/src/test/ui/regions/regions-proc-bound-capture.rs index 0c903b7384992..8617c0e9da8f7 100644 --- a/src/test/ui/regions/regions-proc-bound-capture.rs +++ b/src/test/ui/regions/regions-proc-bound-capture.rs @@ -4,9 +4,9 @@ fn borrowed_proc<'a>(x: &'a isize) -> Box(isize) + 'a> { Box::new(move|| { *x }) } -fn static_proc(x: &isize) -> Box(isize) + 'static> { +fn static_proc(x: &isize) -> Box (isize) + 'static> { // This is illegal, because the region bound on `proc` is 'static. - Box::new(move|| { *x }) //~ ERROR explicit lifetime required in the type of `x` [E0621] + Box::new(move || { *x }) //~ ERROR cannot infer an appropriate lifetime } fn main() { } diff --git a/src/test/ui/regions/regions-proc-bound-capture.stderr b/src/test/ui/regions/regions-proc-bound-capture.stderr index c53af34456ef3..67eee3bb6e281 100644 --- a/src/test/ui/regions/regions-proc-bound-capture.stderr +++ b/src/test/ui/regions/regions-proc-bound-capture.stderr @@ -1,12 +1,21 @@ -error[E0621]: explicit lifetime required in the type of `x` - --> $DIR/regions-proc-bound-capture.rs:9:5 +error[E0759]: cannot infer an appropriate lifetime + --> $DIR/regions-proc-bound-capture.rs:9:14 | -LL | fn static_proc(x: &isize) -> Box(isize) + 'static> { - | ------ help: add explicit lifetime `'static` to the type of `x`: `&'static isize` +LL | fn static_proc(x: &isize) -> Box (isize) + 'static> { + | ------ this data with an anonymous lifetime `'_`... LL | // This is illegal, because the region bound on `proc` is 'static. -LL | Box::new(move|| { *x }) - | ^^^^^^^^^^^^^^^^^^^^^^^ lifetime `'static` required +LL | Box::new(move || { *x }) + | ^^^^^^^^^^^^^^ ...is captured here, requiring it to live as long as `'static` + | +help: consider changing the trait object's explicit `'static` bound to the lifetime of argument `x` + | +LL | fn static_proc(x: &isize) -> Box (isize) + '_> { + | ^^ +help: alternatively, add an explicit `'static` bound to this reference + | +LL | fn static_proc(x: &'static isize) -> Box (isize) + 'static> { + | ^^^^^^^^^^^^^^ error: aborting due to previous error -For more information about this error, try `rustc --explain E0621`. +For more information about this error, try `rustc --explain E0759`. diff --git a/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.stderr b/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.stderr index 1aeabce5e8aaf..88bd990b1e81b 100644 --- a/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.stderr +++ b/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.stderr @@ -1,11 +1,12 @@ -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/arbitrary_self_types_pin_lifetime_impl_trait-async.rs:8:16 | LL | async fn f(self: Pin<&Self>) -> impl Clone { self } - | ^^^^ ---------- ---------- ...and required to be `'static` by this + | ^^^^ ---------- ---------- ...and is required to live as long as `'static` here | | | - | | data with this lifetime... + | | this data with an anonymous lifetime `'_`... | ...is captured here... error: aborting due to previous error +For more information about this error, try `rustc --explain E0759`. diff --git a/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.stderr b/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.stderr index 04c475be787b8..2e10ab3d3f9b8 100644 --- a/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.stderr +++ b/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.stderr @@ -1,16 +1,21 @@ -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/arbitrary_self_types_pin_lifetime_impl_trait.rs:6:44 | LL | fn f(self: Pin<&Self>) -> impl Clone { self } - | ---------- ---------- ^^^^ ...and is captured here - | | | - | | ...is required to be `'static` by this... - | data with this lifetime... + | ---------- ^^^^ ...is captured here... + | | + | this data with an anonymous lifetime `'_`... | -help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the method body at 6:5 +note: ...and is required to live as long as `'static` here + --> $DIR/arbitrary_self_types_pin_lifetime_impl_trait.rs:6:31 + | +LL | fn f(self: Pin<&Self>) -> impl Clone { self } + | ^^^^^^^^^^ +help: to declare that the `impl Trait` captures data from argument `self`, you can add an explicit `'_` lifetime bound | LL | fn f(self: Pin<&Self>) -> impl Clone + '_ { self } | ^^^^ error: aborting due to previous error +For more information about this error, try `rustc --explain E0759`. diff --git a/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr b/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr index 5cf170d566ca9..9ab060328537b 100644 --- a/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr +++ b/src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr @@ -6,20 +6,23 @@ LL | fn baz(g: G, dest: &mut T) -> impl FnOnce() + '_ | | | help: consider introducing lifetime `'a` here: `'a,` -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/missing-lifetimes-in-signature.rs:19:5 | LL | fn foo(g: G, dest: &mut T) -> impl FnOnce() - | ------ ------------- ...is required to be `'static` by this... - | | - | data with this lifetime... + | ------ this data with an anonymous lifetime `'_`... ... LL | / move || { LL | | *dest = g.get(); LL | | } - | |_____^ ...and is captured here + | |_____^ ...is captured here... | -help: to permit non-static references in an `impl Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the function body at 15:1 +note: ...and is required to live as long as `'static` here + --> $DIR/missing-lifetimes-in-signature.rs:15:37 + | +LL | fn foo(g: G, dest: &mut T) -> impl FnOnce() + | ^^^^^^^^^^^^^ +help: to declare that the `impl Trait` captures data from argument `dest`, you can add an explicit `'_` lifetime bound | LL | fn foo(g: G, dest: &mut T) -> impl FnOnce() + '_ | ^^^^ @@ -122,5 +125,5 @@ LL | fn bak<'a, G, T>(g: G, dest: &'a mut T) -> impl FnOnce() + 'a error: aborting due to 7 previous errors -Some errors have detailed explanations: E0261, E0309, E0621. +Some errors have detailed explanations: E0261, E0309, E0621, E0759. For more information about an error, try `rustc --explain E0261`. diff --git a/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr b/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr index 3577dd59289e5..dda5de431d309 100644 --- a/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr +++ b/src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr @@ -1,16 +1,17 @@ -error: cannot infer an appropriate lifetime +error[E0759]: cannot infer an appropriate lifetime --> $DIR/dyn-trait-underscore.rs:8:20 | LL | fn a(items: &[T]) -> Box> { - | ---- data with this lifetime... + | ---- this data with an anonymous lifetime `'_`... LL | // ^^^^^^^^^^^^^^^^^^^^^ bound *here* defaults to `'static` LL | Box::new(items.iter()) - | ---------------^^^^--- ...is captured and required to be `'static` here + | ---------------^^^^--- ...is captured and required to live as long as `'static` here | -help: to permit non-static references in a `dyn Trait` value, you can add an explicit bound for the anonymous lifetime #1 defined on the function body at 6:1 +help: to declare that the trait object captures data from argument `items`, you can add an explicit `'_` lifetime bound | LL | fn a(items: &[T]) -> Box + '_> { | ^^^^ error: aborting due to previous error +For more information about this error, try `rustc --explain E0759`.