Auto merge of #76969 - withoutboats:rawfd-refexive-traits, r=dtolnay

Make RawFd implement the RawFd traits

This PR makes `RawFd` implement `AsRawFd`, `IntoRawFd` and `FromRawFd`, so it can be passed to interfaces that use one of those traits as a bound.

library/std/src/sys/unix/ext/io.rs

@@ -62,6 +62,25 @@ pub trait IntoRawFd {
     fn into_raw_fd(self) -> RawFd;
 }
 
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl AsRawFd for RawFd {
+    fn as_raw_fd(&self) -> RawFd {
+        *self
+    }
+}
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl IntoRawFd for RawFd {
+    fn into_raw_fd(self) -> RawFd {
+        self
+    }
+}
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl FromRawFd for RawFd {
+    unsafe fn from_raw_fd(fd: RawFd) -> RawFd {
+        fd
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl AsRawFd for fs::File {
     fn as_raw_fd(&self) -> RawFd {

library/std/src/sys/vxworks/ext/io.rs

@@ -63,6 +63,25 @@ pub trait IntoRawFd {
     fn into_raw_fd(self) -> RawFd;
 }
 
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl AsRawFd for RawFd {
+    fn as_raw_fd(&self) -> RawFd {
+        *self
+    }
+}
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl IntoRawFd for RawFd {
+    fn into_raw_fd(self) -> RawFd {
+        self
+    }
+}
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl FromRawFd for RawFd {
+    unsafe fn from_raw_fd(fd: RawFd) -> RawFd {
+        fd
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl AsRawFd for fs::File {
     fn as_raw_fd(&self) -> RawFd {

library/std/src/sys/wasi/ext/io.rs

@@ -52,6 +52,25 @@ pub trait IntoRawFd {
     fn into_raw_fd(self) -> RawFd;
 }
 
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl AsRawFd for RawFd {
+    fn as_raw_fd(&self) -> RawFd {
+        *self
+    }
+}
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl IntoRawFd for RawFd {
+    fn into_raw_fd(self) -> RawFd {
+        self
+    }
+}
+#[stable(feature = "raw_fd_reflexive_traits", since = "1.48.0")]
+impl FromRawFd for RawFd {
+    unsafe fn from_raw_fd(fd: RawFd) -> RawFd {
+        fd
+    }
+}
+
 impl AsRawFd for net::TcpStream {
     fn as_raw_fd(&self) -> RawFd {
         self.as_inner().fd().as_raw()