Use #![warn(single_use_lifetimes)]

.travis.yml

@@ -147,6 +147,7 @@ script:
 env:
   global:
     - secure: "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"
+    - RUSTFLAGS=-Dwarnings
 
 notifications:
   email:

futures-channel/src/lib.rs

@@ -9,6 +9,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+// It cannot be included in the published code because this lints have false positives in the minimum required version.
+#![cfg_attr(test, 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 +5,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+// It cannot be included in the published code because this lints have false positives in the minimum required version.
+#![cfg_attr(test, 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 +6,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+// It cannot be included in the published code because this lints have false positives in the minimum required version.
+#![cfg_attr(test, 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 +11,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+// It cannot be included in the published code because this lints have false positives in the minimum required version.
+#![cfg_attr(test, 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 +2,8 @@
 
 #![recursion_limit="128"]
 #![warn(rust_2018_idioms, unreachable_pub)]
+// It cannot be included in the published code because this lints have false positives in the minimum required version.
+#![cfg_attr(test, warn(single_use_lifetimes))]
 #![warn(clippy::all)]
 
 extern crate proc_macro;

futures-sink/src/lib.rs

@@ -5,6 +5,8 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+// It cannot be included in the published code because this lints have false positives in the minimum required version.
+#![cfg_attr(test, 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 +1,8 @@
 //! Utilities to make testing [`Future`s](futures_core::Future) easier
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+// It cannot be included in the published code because this lints have false positives in the minimum required version.
+#![cfg_attr(test, 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 +7,8 @@
 
 #![cfg_attr(not(feature = "std"), no_std)]
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+// It cannot be included in the published code because this lints have false positives in the minimum required version.
+#![cfg_attr(test, 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 +27,8 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 #![warn(missing_docs, missing_debug_implementations, rust_2018_idioms, unreachable_pub)]
+// It cannot be included in the published code because this lints have false positives in the minimum required version.
+#![cfg_attr(test, warn(single_use_lifetimes))]
 #![warn(clippy::all)]
 
 #![doc(test(attr(deny(warnings), allow(dead_code, unused_assignments, unused_variables))))]