Auto merge of #40950 - frewsxcv:rollup, r=frewsxcv

Rollup of 10 pull requests

- Successful merges: #40694, #40842, #40869, #40888, #40898, #40904, #40925, #40928, #40929, #40934
- Failed merges:

3 files changed, 48 insertions, 0 deletions

diff --git a/src/libstd/os/linux/fs.rs b/src/libstd/os/linux/fs.rs
index 11c41816cec..7ebda5ed744 100644
--- a/src/libstd/os/linux/fs.rs
+++ b/src/libstd/os/linux/fs.rs
@@ -34,36 +34,55 @@ pub trait MetadataExt {
     #[allow(deprecated)]
     fn as_raw_stat(&self) -> &raw::stat;
 
+    /// Returns the device ID on which this file resides.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_dev(&self) -> u64;
+    /// Returns the inode number.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_ino(&self) -> u64;
+    /// Returns the file type and mode.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_mode(&self) -> u32;
+    /// Returns the number of hard links to file.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_nlink(&self) -> u64;
+    /// Returns the user ID of the file owner.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_uid(&self) -> u32;
+    /// Returns the group ID of the file owner.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_gid(&self) -> u32;
+    /// Returns the device ID that this file represents. Only relevant for special file.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_rdev(&self) -> u64;
+    /// Returns the size of the file (if it is a regular file or a symbolic link) in bytes.
+    ///
+    /// The size of a symbolic link is the length of the pathname it contains,
+    /// without a terminating null byte.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_size(&self) -> u64;
+    /// Returns the last access time.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_atime(&self) -> i64;
+    /// Returns the last access time, nano seconds part.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_atime_nsec(&self) -> i64;
+    /// Returns the last modification time.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_mtime(&self) -> i64;
+    /// Returns the last modification time, nano seconds part.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_mtime_nsec(&self) -> i64;
+    /// Returns the last status change time.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_ctime(&self) -> i64;
+    /// Returns the last status change time, nano seconds part.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_ctime_nsec(&self) -> i64;
+    /// Returns the "preferred" blocksize for efficient filesystem I/O.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_blksize(&self) -> u64;
+    /// Returns the number of blocks allocated to the file, 512-byte units.
     #[stable(feature = "metadata_ext2", since = "1.8.0")]
     fn st_blocks(&self) -> u64;
 }
diff --git a/src/libstd/process.rs b/src/libstd/process.rs
index d46cf7a26da..7f1a00c707c 100644
--- a/src/libstd/process.rs
+++ b/src/libstd/process.rs
@@ -1056,6 +1056,20 @@ pub fn exit(code: i32) -> ! {
 /// will be run. If a clean shutdown is needed it is recommended to only call
 /// this function at a known point where there are no more destructors left
 /// to run.
+///
+/// # Examples
+///
+/// ```no_run
+/// use std::process;
+///
+/// fn main() {
+///     println!("aborting");
+///
+///     process::abort();
+///
+///     // execution never gets here
+/// }
+/// ```
 #[stable(feature = "process_abort", since = "1.17.0")]
 pub fn abort() -> ! {
     unsafe { ::sys::abort_internal() };
diff --git a/src/libstd/sys/unix/ext/io.rs b/src/libstd/sys/unix/ext/io.rs
index 296235e173d..75aa72e3cff 100644
--- a/src/libstd/sys/unix/ext/io.rs
+++ b/src/libstd/sys/unix/ext/io.rs
@@ -73,6 +73,13 @@ pub trait IntoRawFd {
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
+impl AsRawFd for RawFd {
+    fn as_raw_fd(&self) -> RawFd {
+        *self
+    }
+}
+
+#[stable(feature = "rust1", since = "1.0.0")]
 impl AsRawFd for fs::File {
     fn as_raw_fd(&self) -> RawFd {
         self.as_inner().fd().raw()
@@ -84,6 +91,14 @@ impl FromRawFd for fs::File {
         fs::File::from_inner(sys::fs::File::from_inner(fd))
     }
 }
+
+#[stable(feature = "into_raw_os", since = "1.4.0")]
+impl IntoRawFd for RawFd {
+    fn into_raw_fd(self) -> RawFd {
+        self
+    }
+}
+
 #[stable(feature = "into_raw_os", since = "1.4.0")]
 impl IntoRawFd for fs::File {
     fn into_raw_fd(self) -> RawFd {