diff options
10 files changed, 114 insertions, 98 deletions
diff --git a/src/librustc/ty/sty.rs b/src/librustc/ty/sty.rs index b72468a6ff9..9b3ec599062 100644 --- a/src/librustc/ty/sty.rs +++ b/src/librustc/ty/sty.rs @@ -69,7 +69,7 @@ pub enum BoundRegion { impl BoundRegion { pub fn is_named(&self) -> bool { match *self { - BoundRegion::BrNamed(..) => true, + BoundRegion::BrNamed(_, name) => name != kw::UnderscoreLifetime, _ => false, } } diff --git a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/outlives_suggestion.rs b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/outlives_suggestion.rs index c0cf4eb5285..907119dd203 100644 --- a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/outlives_suggestion.rs +++ b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/outlives_suggestion.rs @@ -78,17 +78,7 @@ impl OutlivesSuggestionBuilder<'a> { match name.source { RegionNameSource::NamedEarlyBoundRegion(..) | RegionNameSource::NamedFreeRegion(..) - | RegionNameSource::Static => { - // FIXME: This is a bit hacky. We should ideally have a semantic way for checking - // if the name is `'_`... - if name.name().with(|name| name != "'_") { - debug!("Region {:?} is suggestable", name); - true - } else { - debug!("Region {:?} is NOT suggestable", name); - false - } - } + | RegionNameSource::Static => true, // Don't give suggestions for upvars, closure return types, or other unnamable // regions. @@ -98,7 +88,8 @@ impl OutlivesSuggestionBuilder<'a> { | RegionNameSource::MatchedAdtAndSegment(..) | RegionNameSource::AnonRegionFromUpvar(..) | RegionNameSource::AnonRegionFromOutput(..) - | RegionNameSource::AnonRegionFromYieldTy(..) => { + | RegionNameSource::AnonRegionFromYieldTy(..) + | RegionNameSource::AnonRegionFromTraitObjAsync(..) => { debug!("Region {:?} is NOT suggestable", name); false } diff --git a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs index e59928987a0..519991e815b 100644 --- a/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs +++ b/src/librustc_mir/borrow_check/nll/region_infer/error_reporting/region_name.rs @@ -55,7 +55,10 @@ crate enum RegionNameSource { AnonRegionFromUpvar(Span, String), /// The region corresponding to the return type of a closure. AnonRegionFromOutput(Span, String, String), + /// The region from a type yielded by a generator. AnonRegionFromYieldTy(Span, String), + /// An anonymous region from a trait object in an async fn. + AnonRegionFromTraitObjAsync(Span), } /// Records region names that have been assigned before so that we can use the same ones in later @@ -113,7 +116,8 @@ impl RegionName { RegionNameSource::MatchedAdtAndSegment(..) | RegionNameSource::AnonRegionFromUpvar(..) | RegionNameSource::AnonRegionFromOutput(..) | - RegionNameSource::AnonRegionFromYieldTy(..) => false, + RegionNameSource::AnonRegionFromYieldTy(..) | + RegionNameSource::AnonRegionFromTraitObjAsync(..) => false, } } @@ -137,7 +141,8 @@ impl RegionName { RegionNameSource::CannotMatchHirTy(span, type_name) => { diag.span_label(*span, format!("has type `{}`", type_name)); } - RegionNameSource::MatchedHirTy(span) => { + RegionNameSource::MatchedHirTy(span) | + RegionNameSource::AnonRegionFromTraitObjAsync(span) => { diag.span_label( *span, format!("let's call the lifetime of this reference `{}`", self), @@ -287,11 +292,30 @@ impl<'tcx> RegionInferenceContext<'tcx> { ty::ReFree(free_region) => match free_region.bound_region { ty::BoundRegion::BrNamed(_, name) => { + // Get the span to point to, even if we don't use the name. let span = self.get_named_span(tcx, error_region, name); - Some(RegionName { - name, - source: RegionNameSource::NamedFreeRegion(span), - }) + debug!("bound region named: {:?}, is_named: {:?}", + name, free_region.bound_region.is_named()); + + if free_region.bound_region.is_named() { + // A named region that is actually named. + Some(RegionName { + name, + source: RegionNameSource::NamedFreeRegion(span), + }) + } else { + // If we spuriously thought that the region is named, we should let the + // system generate a true name for error messages. Currently this can + // happen if we have an elided name in a trait object used in an async fn + // for example: the compiler will generate a region named `'_`, but + // reporting such a name is not actually useful, so we synthesize a name + // for it instead. + let name = self.synthesize_region_name(renctx); + Some(RegionName { + name, + source: RegionNameSource::AnonRegionFromTraitObjAsync(span), + }) + } } ty::BoundRegion::BrEnv => { diff --git a/src/test/ui/async-await/issues/issue-63388-1.nll.stderr b/src/test/ui/async-await/issues/issue-63388-1.nll.stderr index 22610fe54a4..4ae3971e90e 100644 --- a/src/test/ui/async-await/issues/issue-63388-1.nll.stderr +++ b/src/test/ui/async-await/issues/issue-63388-1.nll.stderr @@ -12,12 +12,12 @@ error: lifetime may not live long enough LL | async fn do_sth<'a>( | -- lifetime `'a` defined here LL | &'a self, foo: &dyn Foo - | - lifetime `'_` defined here + | - let's call the lifetime of this reference `'1` LL | ) -> &dyn Foo LL | / { LL | | foo LL | | } - | |_____^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'_` + | |_____^ function was supposed to return data with lifetime `'a` but it is returning data with lifetime `'1` error: aborting due to 2 previous errors diff --git a/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.nll.stderr b/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.nll.stderr index 713d4b75909..5a63553adc5 100644 --- a/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.nll.stderr +++ b/src/test/ui/self/arbitrary_self_types_pin_lifetime_impl_trait-async.nll.stderr @@ -2,11 +2,11 @@ error: lifetime may not live long enough --> $DIR/arbitrary_self_types_pin_lifetime_impl_trait-async.rs:8:48 | LL | async fn f(self: Pin<&Self>) -> impl Clone { self } - | - ^^^^^^^^ returning this value requires that `'_` must outlive `'static` + | - ^^^^^^^^ returning this value requires that `'1` must outlive `'static` | | - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` | -help: to allow this `impl Trait` to capture borrowed data with lifetime `'_`, add `'_` as a constraint +help: to allow this `impl Trait` to capture borrowed data with lifetime `'1`, add `'_` as a constraint | LL | async fn f(self: Pin<&Self>) -> impl Clone + '_ { self } | ^^^^^^^^^^^^^^^ diff --git a/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.nll.stderr b/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.nll.stderr index 7eec31d36e3..b16c01de0af 100644 --- a/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.nll.stderr +++ b/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.nll.stderr @@ -10,19 +10,19 @@ error: lifetime may not live long enough --> $DIR/arbitrary_self_types_pin_lifetime_mismatch-async.rs:8:52 | LL | async fn a(self: Pin<&Foo>, f: &Foo) -> &Foo { f } - | - ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | - ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` error: lifetime may not live long enough --> $DIR/arbitrary_self_types_pin_lifetime_mismatch-async.rs:11:75 | LL | async fn c(self: Pin<&Self>, f: &Foo, g: &Foo) -> (Pin<&Foo>, &Foo) { (self, f) } - | - ^^^^^^^^^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | - ^^^^^^^^^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/arbitrary_self_types_pin_lifetime_mismatch-async.rs:17:58 @@ -36,8 +36,9 @@ error: lifetime may not live long enough --> $DIR/arbitrary_self_types_pin_lifetime_mismatch-async.rs:17:64 | LL | async fn bar<'a>(self: Alias<&Self>, arg: &'a ()) -> &() { arg } - | -- - lifetime `'_` defined here ^^^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'a` - | | + | -- - ^^^ function was supposed to return data with lifetime `'1` but it is returning data with lifetime `'a` + | | | + | | let's call the lifetime of this reference `'1` | lifetime `'a` defined here error: aborting due to 5 previous errors diff --git a/src/test/ui/self/elision/lt-ref-self-async.nll.stderr b/src/test/ui/self/elision/lt-ref-self-async.nll.stderr index 1288759703f..0bf7f63ca23 100644 --- a/src/test/ui/self/elision/lt-ref-self-async.nll.stderr +++ b/src/test/ui/self/elision/lt-ref-self-async.nll.stderr @@ -12,10 +12,10 @@ error: lifetime may not live long enough LL | async fn ref_self(&self, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/lt-ref-self-async.rs:18:48 @@ -31,10 +31,10 @@ error: lifetime may not live long enough LL | async fn ref_Self(self: &Self, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/lt-ref-self-async.rs:22:57 @@ -50,10 +50,10 @@ error: lifetime may not live long enough LL | async fn box_ref_Self(self: Box<&Self>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/lt-ref-self-async.rs:26:57 @@ -69,10 +69,10 @@ error: lifetime may not live long enough LL | async fn pin_ref_Self(self: Pin<&Self>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/lt-ref-self-async.rs:30:66 @@ -88,10 +88,10 @@ error: lifetime may not live long enough LL | async fn box_box_ref_Self(self: Box<Box<&Self>>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/lt-ref-self-async.rs:34:62 @@ -107,10 +107,10 @@ error: lifetime may not live long enough LL | async fn box_pin_Self(self: Box<Pin<&Self>>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error: aborting due to 12 previous errors diff --git a/src/test/ui/self/elision/ref-mut-self-async.nll.stderr b/src/test/ui/self/elision/ref-mut-self-async.nll.stderr index 24e3f7a098f..f0987e0d033 100644 --- a/src/test/ui/self/elision/ref-mut-self-async.nll.stderr +++ b/src/test/ui/self/elision/ref-mut-self-async.nll.stderr @@ -12,10 +12,10 @@ error: lifetime may not live long enough LL | async fn ref_self(&mut self, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-mut-self-async.rs:18:52 @@ -31,10 +31,10 @@ error: lifetime may not live long enough LL | async fn ref_Self(self: &mut Self, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-mut-self-async.rs:22:61 @@ -50,10 +50,10 @@ error: lifetime may not live long enough LL | async fn box_ref_Self(self: Box<&mut Self>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-mut-self-async.rs:26:61 @@ -69,10 +69,10 @@ error: lifetime may not live long enough LL | async fn pin_ref_Self(self: Pin<&mut Self>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-mut-self-async.rs:30:70 @@ -88,10 +88,10 @@ error: lifetime may not live long enough LL | async fn box_box_ref_Self(self: Box<Box<&mut Self>>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-mut-self-async.rs:34:70 @@ -107,10 +107,10 @@ error: lifetime may not live long enough LL | async fn box_pin_ref_Self(self: Box<Pin<&mut Self>>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error: aborting due to 12 previous errors diff --git a/src/test/ui/self/elision/ref-mut-struct-async.nll.stderr b/src/test/ui/self/elision/ref-mut-struct-async.nll.stderr index c0423d1d3e6..5c0261c2f60 100644 --- a/src/test/ui/self/elision/ref-mut-struct-async.nll.stderr +++ b/src/test/ui/self/elision/ref-mut-struct-async.nll.stderr @@ -12,10 +12,10 @@ error: lifetime may not live long enough LL | async fn ref_Struct(self: &mut Struct, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-mut-struct-async.rs:16:65 @@ -31,10 +31,10 @@ error: lifetime may not live long enough LL | async fn box_ref_Struct(self: Box<&mut Struct>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-mut-struct-async.rs:20:65 @@ -50,10 +50,10 @@ error: lifetime may not live long enough LL | async fn pin_ref_Struct(self: Pin<&mut Struct>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-mut-struct-async.rs:24:74 @@ -69,10 +69,10 @@ error: lifetime may not live long enough LL | async fn box_box_ref_Struct(self: Box<Box<&mut Struct>>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-mut-struct-async.rs:28:74 @@ -88,10 +88,10 @@ error: lifetime may not live long enough LL | async fn box_pin_ref_Struct(self: Box<Pin<&mut Struct>>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error: aborting due to 10 previous errors diff --git a/src/test/ui/self/elision/ref-struct-async.nll.stderr b/src/test/ui/self/elision/ref-struct-async.nll.stderr index 6f413a7f49f..440facb9be1 100644 --- a/src/test/ui/self/elision/ref-struct-async.nll.stderr +++ b/src/test/ui/self/elision/ref-struct-async.nll.stderr @@ -12,10 +12,10 @@ error: lifetime may not live long enough LL | async fn ref_Struct(self: &Struct, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-struct-async.rs:16:61 @@ -31,10 +31,10 @@ error: lifetime may not live long enough LL | async fn box_ref_Struct(self: Box<&Struct>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-struct-async.rs:20:61 @@ -50,10 +50,10 @@ error: lifetime may not live long enough LL | async fn pin_ref_Struct(self: Pin<&Struct>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-struct-async.rs:24:70 @@ -69,10 +69,10 @@ error: lifetime may not live long enough LL | async fn box_box_ref_Struct(self: Box<Box<&Struct>>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error[E0700]: hidden type for `impl Trait` captures lifetime that does not appear in bounds --> $DIR/ref-struct-async.rs:28:66 @@ -88,10 +88,10 @@ error: lifetime may not live long enough LL | async fn box_pin_Struct(self: Box<Pin<&Struct>>, f: &u32) -> &u32 { | - | | - | lifetime `'_` defined here - | lifetime `'_` defined here + | let's call the lifetime of this reference `'1` + | let's call the lifetime of this reference `'2` LL | f - | ^ function was supposed to return data with lifetime `'_` but it is returning data with lifetime `'_` + | ^ function was supposed to return data with lifetime `'2` but it is returning data with lifetime `'1` error: aborting due to 10 previous errors |