From 20e032e65007ff1376e8480c1fbdb0a5068028fa Mon Sep 17 00:00:00 2001 From: Gus Wynn Date: Tue, 15 Sep 2020 13:14:35 -0700 Subject: [PATCH 1/3] Make it more clear when complaining about async fn's return types --- .../nice_region_error/different_lifetimes.rs | 112 ++++++++++++------ .../error_reporting/nice_region_error/util.rs | 54 +++++++++ .../async-await/issues/issue-63388-1.stderr | 6 +- .../ret-impl-trait-one.stderr | 5 +- src/test/ui/issues/issue-76547.rs | 38 ++++++ src/test/ui/issues/issue-76547.stderr | 25 ++++ ...f_types_pin_lifetime_mismatch-async.stderr | 21 ++-- .../ui/self/elision/lt-ref-self-async.stderr | 42 ++++--- .../ui/self/elision/ref-mut-self-async.stderr | 42 ++++--- .../self/elision/ref-mut-struct-async.stderr | 35 +++--- .../ui/self/elision/ref-self-async.stderr | 49 ++++---- .../ui/self/elision/ref-struct-async.stderr | 35 +++--- 12 files changed, 331 insertions(+), 133 deletions(-) create mode 100644 src/test/ui/issues/issue-76547.rs create mode 100644 src/test/ui/issues/issue-76547.stderr diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/different_lifetimes.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/different_lifetimes.rs index 7ab18e54f7ea2..59786059fae67 100644 --- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/different_lifetimes.rs +++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/different_lifetimes.rs @@ -102,43 +102,89 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> { None => String::new(), }; - let (span_1, span_2, main_label, span_label) = match (sup_is_ret_type, sub_is_ret_type) { - (None, None) => { - let (main_label_1, span_label_1) = if ty_sup.hir_id == ty_sub.hir_id { + let (span_1, span_2, main_label, span_label, future_return_type) = + match (sup_is_ret_type, sub_is_ret_type) { + (None, None) => { + let (main_label_1, span_label_1) = if ty_sup.hir_id == ty_sub.hir_id { + ( + "this type is declared with multiple lifetimes...".to_owned(), + "...but data with one lifetime flows into the other here".to_owned(), + ) + } else { + ( + "these two types are declared with different lifetimes...".to_owned(), + format!("...but data{} flows{} here", span_label_var1, span_label_var2), + ) + }; + (ty_sup.span, ty_sub.span, main_label_1, span_label_1, None) + } + + (Some(ret_span), _) => { + let sup_future = self.future_return_type(scope_def_id_sup); + let (return_type, action) = if let Some(_) = sup_future { + ("returned future", "held across an await point") + } else { + ("return type", "returned") + }; + ( - "this type is declared with multiple lifetimes...".to_owned(), - "...but data with one lifetime flows into the other here".to_owned(), + ty_sub.span, + ret_span, + format!( + "this parameter and the {} are declared with different lifetimes...", + return_type + ), + format!("...but data{} is {} here", span_label_var1, action), + sup_future, ) - } else { + } + (_, Some(ret_span)) => { + let sub_future = self.future_return_type(scope_def_id_sub); + let (return_type, action) = if let Some(_) = sub_future { + ("returned future", "held across an await point") + } else { + ("return type", "returned") + }; + ( - "these two types are declared with different lifetimes...".to_owned(), - format!("...but data{} flows{} here", span_label_var1, span_label_var2), + ty_sup.span, + ret_span, + format!( + "this parameter and the {} are declared with different lifetimes...", + return_type + ), + format!("...but data{} is {} here", span_label_var1, action), + sub_future, ) - }; - (ty_sup.span, ty_sub.span, main_label_1, span_label_1) - } - - (Some(ret_span), _) => ( - ty_sub.span, - ret_span, - "this parameter and the return type are declared with different lifetimes..." - .to_owned(), - format!("...but data{} is returned here", span_label_var1), - ), - (_, Some(ret_span)) => ( - ty_sup.span, - ret_span, - "this parameter and the return type are declared with different lifetimes..." - .to_owned(), - format!("...but data{} is returned here", span_label_var1), - ), - }; - - struct_span_err!(self.tcx().sess, span, E0623, "lifetime mismatch") - .span_label(span_1, main_label) - .span_label(span_2, String::new()) - .span_label(span, span_label) - .emit(); + } + }; + + let mut e = struct_span_err!(self.tcx().sess, span, E0623, "lifetime mismatch"); + + e.span_label(span_1, main_label); + e.span_label(span_2, String::new()); + e.span_label(span, span_label); + + if let Some(t) = future_return_type { + let snip = self + .tcx() + .sess + .source_map() + .span_to_snippet(t.span) + .ok() + .and_then(|s| match (&t.kind, s.as_str()) { + (rustc_hir::TyKind::Tup(&[]), "") => Some("()".to_string()), + (_, "") => None, + _ => Some(s), + }) + .unwrap_or("{unnamed_type}".to_string()); + + e.span_label( + t.span, + &format!("this `async fn` implicitly returns an `impl Future`", snip), + ); + } + e.emit(); Some(ErrorReported) } } diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs index c055fed43f6d5..ca93b2777ab2a 100644 --- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs +++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/util.rs @@ -85,6 +85,60 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> { }) } + pub(super) fn future_return_type( + &self, + local_def_id: LocalDefId, + ) -> Option<&rustc_hir::Ty<'_>> { + if let Some(hir::IsAsync::Async) = self.asyncness(local_def_id) { + if let rustc_middle::ty::Opaque(def_id, _) = + self.tcx().type_of(local_def_id).fn_sig(self.tcx()).output().skip_binder().kind() + { + match self.tcx().hir().get_if_local(*def_id) { + Some(hir::Node::Item(hir::Item { + kind: + hir::ItemKind::OpaqueTy(hir::OpaqueTy { + bounds, + origin: hir::OpaqueTyOrigin::AsyncFn, + .. + }), + .. + })) => { + for b in bounds.iter() { + if let hir::GenericBound::LangItemTrait( + hir::LangItem::Future, + _span, + _hir_id, + generic_args, + ) = b + { + for type_binding in generic_args.bindings.iter() { + if type_binding.ident.name == rustc_span::sym::Output { + if let hir::TypeBindingKind::Equality { ty } = + type_binding.kind + { + return Some(ty); + } + } + } + } + } + } + _ => {} + } + } + } + None + } + + pub(super) fn asyncness(&self, local_def_id: LocalDefId) -> Option { + // similar to the asyncness fn in rustc_ty::ty + let hir_id = self.tcx().hir().local_def_id_to_hir_id(local_def_id); + let node = self.tcx().hir().get(hir_id); + let fn_like = rustc_middle::hir::map::blocks::FnLikeNode::from_node(node)?; + + Some(fn_like.asyncness()) + } + // Here, we check for the case where the anonymous region // is in the return type. // FIXME(#42703) - Need to handle certain cases here. diff --git a/src/test/ui/async-await/issues/issue-63388-1.stderr b/src/test/ui/async-await/issues/issue-63388-1.stderr index 8813183312ddf..ac29cca9d3f60 100644 --- a/src/test/ui/async-await/issues/issue-63388-1.stderr +++ b/src/test/ui/async-await/issues/issue-63388-1.stderr @@ -2,12 +2,14 @@ error[E0623]: lifetime mismatch --> $DIR/issue-63388-1.rs:14:9 | LL | &'a self, foo: &dyn Foo - | -------- this parameter and the return type are declared with different lifetimes... + | -------- this parameter and the returned future are declared with different lifetimes... LL | ) -> &dyn Foo | -------- + | | + | this `async fn` implicitly returns an `impl Future` LL | { LL | foo - | ^^^ ...but data from `foo` is returned here + | ^^^ ...but data from `foo` is held across an await point here error: aborting due to previous error diff --git a/src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-one.stderr b/src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-one.stderr index 7b8f290d6c2f8..5041b39a9e9d1 100644 --- a/src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-one.stderr +++ b/src/test/ui/async-await/multiple-lifetimes/ret-impl-trait-one.stderr @@ -4,8 +4,9 @@ error[E0623]: lifetime mismatch LL | async fn async_ret_impl_trait1<'a, 'b>(a: &'a u8, b: &'b u8) -> impl Trait<'a> { | ------ ^^^^^^^^^^^^^^ | | | - | | ...but data from `b` is returned here - | this parameter and the return type are declared with different lifetimes... + | | ...but data from `b` is held across an await point here + | | this `async fn` implicitly returns an `impl Future>` + | this parameter and the returned future are declared with different lifetimes... error: aborting due to previous error diff --git a/src/test/ui/issues/issue-76547.rs b/src/test/ui/issues/issue-76547.rs new file mode 100644 index 0000000000000..feec086764a34 --- /dev/null +++ b/src/test/ui/issues/issue-76547.rs @@ -0,0 +1,38 @@ +// Test for for diagnostic improvement issue #76547 +// edition:2018 + +use std::{ + future::Future, + task::{Context, Poll} +}; +use std::pin::Pin; + +pub struct ListFut<'a>(&'a mut [&'a mut [u8]]); +impl<'a> Future for ListFut<'a> { + type Output = (); + + fn poll(self: Pin<&mut Self>, _cx: &mut Context) -> Poll { + unimplemented!() + } +} + +async fn fut(bufs: &mut [&mut [u8]]) { + ListFut(bufs).await + //~^ ERROR lifetime mismatch +} + +pub struct ListFut2<'a>(&'a mut [&'a mut [u8]]); +impl<'a> Future for ListFut2<'a> { + type Output = i32; + + fn poll(self: Pin<&mut Self>, _cx: &mut Context) -> Poll { + unimplemented!() + } +} + +async fn fut2(bufs: &mut [&mut [u8]]) -> i32 { + ListFut2(bufs).await + //~^ ERROR lifetime mismatch +} + +fn main() {} diff --git a/src/test/ui/issues/issue-76547.stderr b/src/test/ui/issues/issue-76547.stderr new file mode 100644 index 0000000000000..9bfb0f28028cb --- /dev/null +++ b/src/test/ui/issues/issue-76547.stderr @@ -0,0 +1,25 @@ +error[E0623]: lifetime mismatch + --> $DIR/issue-76547.rs:20:13 + | +LL | async fn fut(bufs: &mut [&mut [u8]]) { + | --------- - + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... +LL | ListFut(bufs).await + | ^^^^ ...but data from `bufs` is held across an await point here + +error[E0623]: lifetime mismatch + --> $DIR/issue-76547.rs:34:14 + | +LL | async fn fut2(bufs: &mut [&mut [u8]]) -> i32 { + | --------- --- + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... +LL | ListFut2(bufs).await + | ^^^^ ...but data from `bufs` is held across an await point here + +error: aborting due to 2 previous errors + +For more information about this error, try `rustc --explain E0623`. diff --git a/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.stderr b/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.stderr index 37297032632e1..e6846fb40494f 100644 --- a/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.stderr +++ b/src/test/ui/self/arbitrary_self_types_pin_lifetime_mismatch-async.stderr @@ -2,25 +2,28 @@ error[E0623]: lifetime mismatch --> $DIR/arbitrary_self_types_pin_lifetime_mismatch-async.rs:8:52 | LL | async fn a(self: Pin<&Foo>, f: &Foo) -> &Foo { f } - | ---- ---- ^ ...but data from `f` is returned here - | | - | this parameter and the return type are declared with different lifetimes... + | ---- ---- ^ ...but data from `f` is held across an await point here + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... error[E0623]: lifetime mismatch --> $DIR/arbitrary_self_types_pin_lifetime_mismatch-async.rs:11:82 | LL | async fn c(self: Pin<&Self>, f: &Foo, g: &Foo) -> (Pin<&Foo>, &Foo) { (self, f) } - | ----- ----------------- ^ ...but data from `f` is returned here - | | - | this parameter and the return type are declared with different lifetimes... + | ----- ----------------- ^ ...but data from `f` is held across an await point here + | | | + | | this `async fn` implicitly returns an `impl Future, &Foo)>` + | this parameter and the returned future are declared with different lifetimes... error[E0623]: lifetime mismatch --> $DIR/arbitrary_self_types_pin_lifetime_mismatch-async.rs:17:64 | LL | async fn bar<'a>(self: Alias<&Self>, arg: &'a ()) -> &() { arg } - | ----- --- ^^^ ...but data from `arg` is returned here - | | - | this parameter and the return type are declared with different lifetimes... + | ----- --- ^^^ ...but data from `arg` is held across an await point here + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... error: aborting due to 3 previous errors diff --git a/src/test/ui/self/elision/lt-ref-self-async.stderr b/src/test/ui/self/elision/lt-ref-self-async.stderr index badd973c37f08..3221d27085096 100644 --- a/src/test/ui/self/elision/lt-ref-self-async.stderr +++ b/src/test/ui/self/elision/lt-ref-self-async.stderr @@ -3,60 +3,66 @@ error[E0623]: lifetime mismatch | LL | async fn ref_self(&self, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/lt-ref-self-async.rs:19:9 | LL | async fn ref_Self(self: &Self, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/lt-ref-self-async.rs:23:9 | LL | async fn box_ref_Self(self: Box<&Self>, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/lt-ref-self-async.rs:27:9 | LL | async fn pin_ref_Self(self: Pin<&Self>, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/lt-ref-self-async.rs:31:9 | LL | async fn box_box_ref_Self(self: Box>, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/lt-ref-self-async.rs:35:9 | LL | async fn box_pin_Self(self: Box>, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error: aborting due to 6 previous errors diff --git a/src/test/ui/self/elision/ref-mut-self-async.stderr b/src/test/ui/self/elision/ref-mut-self-async.stderr index 73d942a83f89a..b6ca986923d2e 100644 --- a/src/test/ui/self/elision/ref-mut-self-async.stderr +++ b/src/test/ui/self/elision/ref-mut-self-async.stderr @@ -3,60 +3,66 @@ error[E0623]: lifetime mismatch | LL | async fn ref_self(&mut self, f: &u32) -> &u32 { | --------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-mut-self-async.rs:19:9 | LL | async fn ref_Self(self: &mut Self, f: &u32) -> &u32 { | --------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-mut-self-async.rs:23:9 | LL | async fn box_ref_Self(self: Box<&mut Self>, f: &u32) -> &u32 { | --------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-mut-self-async.rs:27:9 | LL | async fn pin_ref_Self(self: Pin<&mut Self>, f: &u32) -> &u32 { | --------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-mut-self-async.rs:31:9 | LL | async fn box_box_ref_Self(self: Box>, f: &u32) -> &u32 { | --------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-mut-self-async.rs:35:9 | LL | async fn box_pin_ref_Self(self: Box>, f: &u32) -> &u32 { | --------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error: aborting due to 6 previous errors diff --git a/src/test/ui/self/elision/ref-mut-struct-async.stderr b/src/test/ui/self/elision/ref-mut-struct-async.stderr index 7d613c574486c..eda15d76390b6 100644 --- a/src/test/ui/self/elision/ref-mut-struct-async.stderr +++ b/src/test/ui/self/elision/ref-mut-struct-async.stderr @@ -3,50 +3,55 @@ error[E0623]: lifetime mismatch | LL | async fn ref_Struct(self: &mut Struct, f: &u32) -> &u32 { | ----------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-mut-struct-async.rs:17:9 | LL | async fn box_ref_Struct(self: Box<&mut Struct>, f: &u32) -> &u32 { | ----------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-mut-struct-async.rs:21:9 | LL | async fn pin_ref_Struct(self: Pin<&mut Struct>, f: &u32) -> &u32 { | ----------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-mut-struct-async.rs:25:9 | LL | async fn box_box_ref_Struct(self: Box>, f: &u32) -> &u32 { | ----------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-mut-struct-async.rs:29:9 | LL | async fn box_pin_ref_Struct(self: Box>, f: &u32) -> &u32 { | ----------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error: aborting due to 5 previous errors diff --git a/src/test/ui/self/elision/ref-self-async.stderr b/src/test/ui/self/elision/ref-self-async.stderr index bda958241b67b..b42caa88c6fef 100644 --- a/src/test/ui/self/elision/ref-self-async.stderr +++ b/src/test/ui/self/elision/ref-self-async.stderr @@ -3,70 +3,77 @@ error[E0623]: lifetime mismatch | LL | async fn ref_self(&self, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-self-async.rs:29:9 | LL | async fn ref_Self(self: &Self, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-self-async.rs:33:9 | LL | async fn box_ref_Self(self: Box<&Self>, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-self-async.rs:37:9 | LL | async fn pin_ref_Self(self: Pin<&Self>, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-self-async.rs:41:9 | LL | async fn box_box_ref_Self(self: Box>, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-self-async.rs:45:9 | LL | async fn box_pin_ref_Self(self: Box>, f: &u32) -> &u32 { | ----- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-self-async.rs:49:9 | LL | async fn wrap_ref_Self_Self(self: Wrap<&Self, Self>, f: &u8) -> &u8 { | ----- --- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error: aborting due to 7 previous errors diff --git a/src/test/ui/self/elision/ref-struct-async.stderr b/src/test/ui/self/elision/ref-struct-async.stderr index fc85450c4a7cd..599becd308062 100644 --- a/src/test/ui/self/elision/ref-struct-async.stderr +++ b/src/test/ui/self/elision/ref-struct-async.stderr @@ -3,50 +3,55 @@ error[E0623]: lifetime mismatch | LL | async fn ref_Struct(self: &Struct, f: &u32) -> &u32 { | ------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-struct-async.rs:17:9 | LL | async fn box_ref_Struct(self: Box<&Struct>, f: &u32) -> &u32 { | ------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-struct-async.rs:21:9 | LL | async fn pin_ref_Struct(self: Pin<&Struct>, f: &u32) -> &u32 { | ------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-struct-async.rs:25:9 | LL | async fn box_box_ref_Struct(self: Box>, f: &u32) -> &u32 { | ------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error[E0623]: lifetime mismatch --> $DIR/ref-struct-async.rs:29:9 | LL | async fn box_pin_Struct(self: Box>, f: &u32) -> &u32 { | ------- ---- - | | - | this parameter and the return type are declared with different lifetimes... + | | | + | | this `async fn` implicitly returns an `impl Future` + | this parameter and the returned future are declared with different lifetimes... LL | f - | ^ ...but data from `f` is returned here + | ^ ...but data from `f` is held across an await point here error: aborting due to 5 previous errors From aaf06d8d67d9c94a609790f8593440e30b0a56d4 Mon Sep 17 00:00:00 2001 From: Gus Wynn Date: Mon, 9 Nov 2020 16:27:15 -0800 Subject: [PATCH 2/3] add nll compare mode stderr file --- src/test/ui/issues/issue-76547.nll.stderr | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) create mode 100644 src/test/ui/issues/issue-76547.nll.stderr diff --git a/src/test/ui/issues/issue-76547.nll.stderr b/src/test/ui/issues/issue-76547.nll.stderr new file mode 100644 index 0000000000000..2456d6a147488 --- /dev/null +++ b/src/test/ui/issues/issue-76547.nll.stderr @@ -0,0 +1,20 @@ +error: lifetime may not live long enough + --> $DIR/issue-76547.rs:19:14 + | +LL | async fn fut(bufs: &mut [&mut [u8]]) { + | ^^^^ - - let's call the lifetime of this reference `'2` + | | | + | | let's call the lifetime of this reference `'1` + | assignment requires that `'1` must outlive `'2` + +error: lifetime may not live long enough + --> $DIR/issue-76547.rs:33:15 + | +LL | async fn fut2(bufs: &mut [&mut [u8]]) -> i32 { + | ^^^^ - - let's call the lifetime of this reference `'2` + | | | + | | let's call the lifetime of this reference `'1` + | assignment requires that `'1` must outlive `'2` + +error: aborting due to 2 previous errors + From 6be48475fe51ca8dd9ca35d931319e9f3e008c58 Mon Sep 17 00:00:00 2001 From: Tyler Mandry Date: Mon, 9 Nov 2020 17:44:03 -0800 Subject: [PATCH 3/3] Update src/test/ui/issues/issue-76547.rs Co-authored-by: Camelid --- src/test/ui/issues/issue-76547.rs | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/test/ui/issues/issue-76547.rs b/src/test/ui/issues/issue-76547.rs index feec086764a34..5b3ee5b95c4cb 100644 --- a/src/test/ui/issues/issue-76547.rs +++ b/src/test/ui/issues/issue-76547.rs @@ -1,4 +1,4 @@ -// Test for for diagnostic improvement issue #76547 +// Test for diagnostic improvement issue #76547 // edition:2018 use std::{