chore: reduce dependency to pin-utils

Signed-off-by: tison <wander4096@gmail.com>

Author: tisonkun

futures-util/Cargo.toml

@@ -41,7 +41,6 @@ slab = { version = "0.4.2", default-features = false, optional = true }
 memchr = { version = "2.2", optional = true }
 futures_01 = { version = "0.1.25", optional = true, package = "futures" }
 tokio-io = { version = "0.1.9", optional = true }
-pin-utils = "0.1.0"
 pin-project-lite = "0.2.6"
 spin = { version = "0.9.8", optional = true }
 

futures-util/src/future/future/mod.rs

@@ -18,7 +18,6 @@ use futures_core::{
     stream::Stream,
     task::{Context, Poll},
 };
-use pin_utils::pin_mut;
 
 // Combinators
 
@@ -112,6 +111,36 @@ mod shared;
 #[cfg(any(feature = "std", all(feature = "alloc", feature = "spin")))]
 pub use self::shared::{Shared, WeakShared};
 
+/// Pins a value on the stack.
+///
+/// **Note:** Since Rust 1.68, this macro is soft-deprecated in favor of
+/// [`pin!`](https://doc.rust-lang.org/std/pin/macro.pin.html) macro
+/// in the standard library.
+///
+/// # Example
+///
+/// ```rust
+/// # use futures_util::pin_mut;
+/// # use core::pin::Pin;
+/// # struct Foo {}
+/// let foo = Foo { /* ... */ };
+/// pin_mut!(foo);
+/// let _: Pin<&mut Foo> = foo;
+/// ```
+#[macro_export]
+macro_rules! pin_mut {
+    ($($x:ident),* $(,)?) => { $(
+        // Move the value to ensure that it is owned
+        let mut $x = $x;
+        // Shadow the original binding so that it can't be directly accessed
+        // ever again.
+        #[allow(unused_mut)]
+        let mut $x = unsafe {
+            ::std::pin::Pin::new_unchecked(&mut $x)
+        };
+    )* }
+}
+
 impl<T: ?Sized> FutureExt for T where T: Future {}
 
 /// An extension trait for `Future`s that provides a variety of convenient

futures-util/src/lib.rs

@@ -23,7 +23,6 @@ extern crate std;
 
 // Macro re-exports
 pub use futures_core::ready;
-pub use pin_utils::pin_mut;
 
 #[cfg(feature = "async-await")]
 #[macro_use]