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<Output = {}>`", snip),
+ );
+ }
+ e.emit();
Some(ErrorReported)
}
}
})
}
+ 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<hir::IsAsync> {
+ // 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.
--> $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<Output = &dyn Foo>`
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
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<Output = impl Trait<'a>>`
+ | this parameter and the returned future are declared with different lifetimes...
error: aborting due to previous error
--- /dev/null
+// 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<Self::Output> {
+ 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<Self::Output> {
+ unimplemented!()
+ }
+}
+
+async fn fut2(bufs: &mut [&mut [u8]]) -> i32 {
+ ListFut2(bufs).await
+ //~^ ERROR lifetime mismatch
+}
+
+fn main() {}
--- /dev/null
+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<Output = ()>`
+ | 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<Output = i32>`
+ | 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`.
--> $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<Output = &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: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<Output = (Pin<&Foo>, &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<Output = &()>`
+ | this parameter and the returned future are declared with different lifetimes...
error: aborting due to 3 previous errors
|
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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Box<&Self>>, f: &u32) -> &u32 {
| ----- ----
- | |
- | this parameter and the return type are declared with different lifetimes...
+ | | |
+ | | this `async fn` implicitly returns an `impl Future<Output = &u32>`
+ | 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<Pin<&Self>>, f: &u32) -> &u32 {
| ----- ----
- | |
- | this parameter and the return type are declared with different lifetimes...
+ | | |
+ | | this `async fn` implicitly returns an `impl Future<Output = &u32>`
+ | 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
|
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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<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<Output = &u32>`
+ | 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<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<Output = &u32>`
+ | 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
|
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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<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<Output = &u32>`
+ | 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<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<Output = &u32>`
+ | 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
|
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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Box<&Self>>, f: &u32) -> &u32 {
| ----- ----
- | |
- | this parameter and the return type are declared with different lifetimes...
+ | | |
+ | | this `async fn` implicitly returns an `impl Future<Output = &u32>`
+ | 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<Pin<&Self>>, f: &u32) -> &u32 {
| ----- ----
- | |
- | this parameter and the return type are declared with different lifetimes...
+ | | |
+ | | this `async fn` implicitly returns an `impl Future<Output = &u32>`
+ | 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<Output = &u8>`
+ | 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
|
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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Output = &u32>`
+ | 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<Box<&Struct>>, f: &u32) -> &u32 {
| ------- ----
- | |
- | this parameter and the return type are declared with different lifetimes...
+ | | |
+ | | this `async fn` implicitly returns an `impl Future<Output = &u32>`
+ | 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<Pin<&Struct>>, f: &u32) -> &u32 {
| ------- ----
- | |
- | this parameter and the return type are declared with different lifetimes...
+ | | |
+ | | this `async fn` implicitly returns an `impl Future<Output = &u32>`
+ | 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
projects / rust.git / commitdiff