Use #![warn(single_use_lifetimes)]

Author: taiki-e

futures-channel/src/lib.rs

@@ -9,6 +9,7 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+#![warn(single_use_lifetimes)]
 #![warn(clippy::all)]
 
 #![doc(test(attr(deny(warnings), allow(dead_code, unused_assignments, unused_variables))))]

futures-core/src/future/future_obj.rs

@@ -21,13 +21,15 @@ pub struct LocalFutureObj<'a, T> {
 
 impl<T> Unpin for LocalFutureObj<'_, T> {}
 
+#[allow(single_use_lifetimes)]
 #[allow(clippy::transmute_ptr_to_ptr)]
 unsafe fn remove_future_lifetime<'a, T>(ptr: *mut (dyn Future<Output = T> + 'a))
     -> *mut (dyn Future<Output = T> + 'static)
 {
     mem::transmute(ptr)
 }
 
+#[allow(single_use_lifetimes)]
 unsafe fn remove_drop_lifetime<'a, T>(ptr: unsafe fn (*mut (dyn Future<Output = T> + 'a)))
     -> unsafe fn(*mut (dyn Future<Output = T> + 'static))
 {

futures-core/src/lib.rs

@@ -5,6 +5,7 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+#![warn(single_use_lifetimes)]
 #![warn(clippy::all)]
 
 #![doc(test(attr(deny(warnings), allow(dead_code, unused_assignments, unused_variables))))]

futures-executor/src/lib.rs

@@ -6,6 +6,7 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+#![warn(single_use_lifetimes)]
 #![warn(clippy::all)]
 
 #![doc(test(attr(deny(warnings), allow(dead_code, unused_assignments, unused_variables))))]

futures-io/src/lib.rs

@@ -11,6 +11,7 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+#![warn(single_use_lifetimes)]
 #![warn(clippy::all)]
 
 #![doc(test(attr(deny(warnings), allow(dead_code, unused_assignments, unused_variables))))]

futures-select-macro/src/lib.rs

@@ -2,6 +2,7 @@
 
 #![recursion_limit="128"]
 #![warn(rust_2018_idioms, unreachable_pub)]
+#![warn(single_use_lifetimes)]
 #![warn(clippy::all)]
 
 extern crate proc_macro;

futures-sink/src/lib.rs

@@ -5,6 +5,7 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+#![warn(single_use_lifetimes)]
 #![warn(clippy::all)]
 
 #![doc(test(attr(deny(warnings), allow(dead_code, unused_assignments, unused_variables))))]

futures-test/src/lib.rs

@@ -1,6 +1,7 @@
 //! Utilities to make testing [`Future`s](futures_core::Future) easier
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+#![warn(single_use_lifetimes)]
 #![warn(clippy::all)]
 
 #![doc(test(attr(deny(warnings), allow(dead_code, unused_assignments, unused_variables))))]

futures-util/src/compat/executor.rs

@@ -81,6 +81,7 @@ where Ex: Executor01<Executor01Future>,
     }
 }
 
+#[allow(single_use_lifetimes)] // https://github.com/rust-lang/rust/issues/55058
 impl<Sp, Fut> Executor01<Fut> for Compat<Sp>
 where
     for<'a> &'a Sp: Spawn03,

futures-util/src/lib.rs

@@ -7,6 +7,7 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+#![warn(single_use_lifetimes)]
 #![warn(clippy::all)]
 
 #![doc(test(attr(deny(warnings), allow(dead_code, unused_assignments, unused_variables))))]

futures/src/lib.rs

@@ -27,6 +27,7 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+#![warn(single_use_lifetimes)]
 #![warn(clippy::all)]
 
 #![doc(test(attr(deny(warnings), allow(dead_code, unused_assignments, unused_variables))))]