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Rollup merge of #72804 - estebank:opaque-missing-lts-in-fn-2, r=nikomatsakis

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Further tweak lifetime errors involving `dyn Trait` and `impl Trait` in return position

* Suggest substituting `'static` lifetime in impl/dyn `Trait + 'static` instead of `Trait + 'static + '_`
* When `'static` is explicit, also suggest constraining argument with it
* Reduce verbosity of suggestion message and mention lifetime in label
* Tweak output for overlapping required/captured spans
* Give these errors an error code

Follow up to #72543.

r? @nikomatsakis
This commit is contained in:
Manish Goregaokar 2020-06-18 15:20:43 -07:00 committed by GitHub
commit 40fd2bdcfe
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25 changed files with 617 additions and 211 deletions
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1
src/librustc_error_codes/error_codes.rs
View File

@ -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"),

67
src/librustc_error_codes/error_codes/E0759.md Normal file
View File

@ -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<dyn Debug> {
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<dyn Debug + 'static> {
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<dyn Debug + '_> {
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<dyn Debug + 'a> {
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

3
src/librustc_infer/infer/error_reporting/mod.rs
View File

@ -2035,8 +2035,7 @@ 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
)
}

184
src/librustc_infer/infer/error_reporting/nice_region_error/static_impl_trait.rs
View File

@ -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<ErrorReported> {
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<dyn Debug> { 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<dyn Debug> { 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 + '_)`
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::OpaqueDef(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(
fn_return_span.shrink_to_hi(),
&msg,
format!(" + {}", lifetime_name),
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);

13
src/librustc_middle/ty/context.rs
View File

@ -1405,7 +1405,10 @@ 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 {
@ -1451,16 +1454,18 @@ 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,
}
}

13
src/librustc_middle/ty/diagnostics.rs
View File

@ -236,21 +236,24 @@ pub fn suggest_constraining_type_param(
}
}
pub struct TraitObjectVisitor(pub Vec<rustc_span::Span>);
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<Self::Map> {
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);
}
}
}

7
src/test/ui/async-await/issues/issue-62097.stderr
View File

@ -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`.

38
src/test/ui/impl-trait/must_outlive_least_region_or_bound.nll.stderr
View File

@ -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<T:Debug>(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`.

21
src/test/ui/impl-trait/must_outlive_least_region_or_bound.rs
View File

@ -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<dyn Debug> { Box::new(x) }
//~^ ERROR cannot infer an appropriate lifetime
fn explicit3<'a>(x: &'a i32) -> Box<dyn Debug> { Box::new(x) }
//~^ ERROR cannot infer an appropriate lifetime
fn elided4(x: &i32) -> Box<dyn Debug + 'static> { Box::new(x) }
//~^ ERROR cannot infer an appropriate lifetime
fn explicit4<'a>(x: &'a i32) -> Box<dyn Debug + 'static> { Box::new(x) }
//~^ ERROR cannot infer an appropriate lifetime
trait LifetimeTrait<'a> {}
impl<'a> LifetimeTrait<'a> for &'a i32 {}

174
src/test/ui/impl-trait/must_outlive_least_region_or_bound.stderr
View File

@ -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 + 'a { x }
| ^^^^
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> + '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<T:Debug>(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<dyn Debug> { 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<dyn Debug + '_> { Box::new(x) }
| ^^^^
Some errors have detailed explanations: E0310, E0623.
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<dyn Debug> { 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<dyn Debug + 'a> { 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<dyn Debug + 'static> { 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<dyn Debug + '_> { Box::new(x) }
| ^^
help: alternatively, add an explicit `'static` bound to this reference
|
LL | fn elided4(x: &'static i32) -> Box<dyn Debug + 'static> { 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<dyn Debug + 'static> { 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<dyn Debug + 'a> { Box::new(x) }
| ^^
help: alternatively, add an explicit `'static` bound to this reference
|
LL | fn explicit4<'a>(x: &'static i32) -> Box<dyn Debug + 'static> { Box::new(x) }
| ^^^^^^^^^^^^
error: aborting due to 12 previous errors
Some errors have detailed explanations: E0310, E0621, E0623, E0759.
For more information about an error, try `rustc --explain E0310`.

31
src/test/ui/impl-trait/static-return-lifetime-infered.stderr
View File

@ -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<Item=u32> {
| ----- ----------------------- ...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<Item=u32> {
| ^^^^^^^^^^^^^^^^^^^^^^^
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<Item=u32> + '_ {
| ^^^^
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<Item=u32> {
| -------- ----------------------- ...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<Item=u32> {
| ^^^^^^^^^^^^^^^^^^^^^^^
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<Item=u32> + 'a {
| ^^^^
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0759`.

12
src/test/ui/issues/issue-16922.stderr
View File

@ -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<T: Any>(value: &T) -> Box<dyn Any> {
| -- data with this lifetime...
| -- this data with an anonymous lifetime `'_`...
LL | Box::new(value) as Box<dyn Any>
| ---------^^^^^-
| | |
| | ...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<T: Any>(value: &T) -> Box<dyn Any + '_> {
| ^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0759`.

11
src/test/ui/object-lifetime/object-lifetime-default-from-box-error.stderr
View File

@ -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<dyn SomeTrait> {
| --------------- 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<dyn SomeTrait + '_> {
| ^^^^
@ -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`.

27
src/test/ui/regions/region-object-lifetime-in-coercion.nll.stderr
View File

@ -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<dyn Foo + 'static> {
| ----- 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<dyn Foo + 'static> = Box::new(v);
| ^^^^^^^^^^^^^^^^^^^^^^ lifetime `'static` required
error[E0621]: explicit lifetime required in the type of `v`
--> $DIR/region-object-lifetime-in-coercion.rs:14:5
|
LL | fn b(v: &[u8]) -> Box<dyn Foo + 'static> {
| ----- help: add explicit lifetime `'static` to the type of `v`: `&'static [u8]`
LL | Box::new(v)
| ^^^^^^^^^^^ lifetime `'static` required
| ^^^^^^^^^^^^^^^^^^^^^^ type annotation 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:13:5
|
LL | fn b(v: &[u8]) -> Box<dyn Foo + 'static> {
| - let's call the lifetime of this reference `'1`
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:19:5
|
LL | fn c(v: &[u8]) -> Box<dyn Foo> {
| - 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<dyn Foo+'b> {
| -- -- 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`.

5
src/test/ui/regions/region-object-lifetime-in-coercion.rs
View File

@ -5,13 +5,12 @@ trait Foo {}
impl<'a> Foo for &'a [u8] {}
fn a(v: &[u8]) -> Box<dyn Foo + 'static> {
let x: Box<dyn Foo + 'static> = Box::new(v);
//~^ ERROR explicit lifetime required in the type of `v` [E0621]
let x: Box<dyn Foo + 'static> = Box::new(v); //~ ERROR cannot infer an appropriate lifetime
x
}
fn b(v: &[u8]) -> Box<dyn Foo + 'static> {
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<dyn Foo> {

63
src/test/ui/regions/region-object-lifetime-in-coercion.stderr
View File

@ -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<dyn Foo + 'static> {
| ----- help: add explicit lifetime `'static` to the type of `v`: `&'static [u8]`
| ----- this data with an anonymous lifetime `'_`...
LL | let x: Box<dyn Foo + 'static> = 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<dyn Foo + '_> {
| ^^
help: alternatively, add an explicit `'static` bound to this reference
|
LL | fn a(v: &'static [u8]) -> Box<dyn Foo + 'static> {
| ^^^^^^^^^^^^^
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<dyn Foo + 'static> {
| ----- 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<dyn Foo + '_> {
| ^^
help: alternatively, add an explicit `'static` bound to this reference
|
LL | fn b(v: &'static [u8]) -> Box<dyn Foo + 'static> {
| ^^^^^^^^^^^^^
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<dyn Foo> {
| ----- 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<dyn Foo + '_> {
| ^^^^
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<dyn Foo+'b> {
| ^^
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<dyn Foo+'b> {
| ^^
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`.

32
src/test/ui/regions/regions-close-object-into-object-2.stderr
View File

@ -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 | box B(&*v) as Box<dyn X>
| ^^^
|
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
|
LL | fn g<'a, T: 'static>(v: Box<dyn A<T> + 'a>) -> Box<dyn X + 'static> {
| ------------------ this data with lifetime `'a`...
LL | box B(&*v) as Box<dyn 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 `v`
|
LL | fn g<'a, T: 'static>(v: Box<dyn A<T> + 'a>) -> Box<dyn X + 'a> {
| ^^
note: ...so that the type `(dyn A<T> + 'a)` is not borrowed for too long
--> $DIR/regions-close-object-into-object-2.rs:10:11
help: alternatively, add an explicit `'static` bound to this reference
|
LL | box B(&*v) as Box<dyn X>
| ^^^
= 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 | box B(&*v) as Box<dyn X>
| ^^^^^^^^^^^^^^^^^^^^^^^^
= note: expected `std::boxed::Box<(dyn X + 'static)>`
found `std::boxed::Box<dyn X>`
LL | fn g<'a, T: 'static>(v: std::boxed::Box<(dyn A<T> + 'static)>) -> Box<dyn X + 'static> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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`.

32
src/test/ui/regions/regions-close-object-into-object-4.stderr
View File

@ -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 | box B(&*v) as Box<dyn X>
| ^^^
|
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
|
LL | fn i<'a, T, U>(v: Box<dyn A<U>+'a>) -> Box<dyn X + 'static> {
| ---------------- this data with lifetime `'a`...
LL | box B(&*v) as Box<dyn 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 `v`
|
LL | fn i<'a, T, U>(v: Box<dyn A<U>+'a>) -> Box<dyn X + 'a> {
| ^^
note: ...so that the type `(dyn A<U> + 'a)` is not borrowed for too long
--> $DIR/regions-close-object-into-object-4.rs:10:11
help: alternatively, add an explicit `'static` bound to this reference
|
LL | box B(&*v) as Box<dyn X>
| ^^^
= 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 | box B(&*v) as Box<dyn X>
| ^^^^^^^^^^^^^^^^^^^^^^^^
= note: expected `std::boxed::Box<(dyn X + 'static)>`
found `std::boxed::Box<dyn X>`
LL | fn i<'a, T, U>(v: std::boxed::Box<(dyn A<U> + 'static)>) -> Box<dyn X + 'static> {
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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`.

11
src/test/ui/regions/regions-proc-bound-capture.nll.stderr Normal file
View File

@ -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<dyn FnMut() -> (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

4
src/test/ui/regions/regions-proc-bound-capture.rs
View File

@ -4,9 +4,9 @@ fn borrowed_proc<'a>(x: &'a isize) -> Box<dyn FnMut()->(isize) + 'a> {
Box::new(move|| { *x })
}
fn static_proc(x: &isize) -> Box<dyn FnMut()->(isize) + 'static> {
fn static_proc(x: &isize) -> Box<dyn FnMut() -> (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() { }

23
src/test/ui/regions/regions-proc-bound-capture.stderr
View File

@ -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<dyn FnMut()->(isize) + 'static> {
| ------ help: add explicit lifetime `'static` to the type of `x`: `&'static isize`
LL | fn static_proc(x: &isize) -> Box<dyn FnMut() -> (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<dyn FnMut() -> (isize) + '_> {
| ^^
help: alternatively, add an explicit `'static` bound to this reference
|
LL | fn static_proc(x: &'static isize) -> Box<dyn FnMut() -> (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`.

7
src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.stderr
View File

@ -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`.

17
src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait.stderr
View File

@ -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`.

17
src/test/ui/suggestions/lifetimes/missing-lifetimes-in-signature.stderr
View File

@ -6,20 +6,23 @@ LL | fn baz<G: 'a, T>(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, T>(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, T>(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, T>(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`.

9
src/test/ui/underscore-lifetime/dyn-trait-underscore.stderr
View File

@ -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<T>(items: &[T]) -> Box<dyn Iterator<Item=&T>> {
| ---- 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<T>(items: &[T]) -> Box<dyn Iterator<Item=&T> + '_> {
| ^^^^
error: aborting due to previous error
For more information about this error, try `rustc --explain E0759`.