Add and insta-stabilize std::io::ErrorKind::NotSupported

Author: CDirkx

library/std/src/io/error.rs

@@ -180,6 +180,10 @@ pub enum ErrorKind {
     /// read.
     #[stable(feature = "read_exact", since = "1.6.0")]
     UnexpectedEof,
+
+    /// This operation is not supported on this platform.
+    #[stable(feature = "not_supported_error", since = "1.50.0")]
+    NotSupported,
 }
 
 impl ErrorKind {
@@ -203,6 +207,7 @@ impl ErrorKind {
             ErrorKind::Interrupted => "operation interrupted",
             ErrorKind::Other => "other os error",
             ErrorKind::UnexpectedEof => "unexpected end of file",
+            ErrorKind::NotSupported => "not supported",
         }
     }
 }

library/std/src/sys/unix/l4re.rs

@@ -1,6 +1,6 @@
 macro_rules! unimpl {
     () => {
-        return Err(io::Error::new_const(io::ErrorKind::Other, &"No networking available on L4Re."));
+        return Err(io::Error::new_const(io::ErrorKind::NotSupported, &"No networking available on L4Re."));
     };
 }
 

library/std/src/sys/unsupported/common.rs

@@ -18,7 +18,7 @@ pub fn unsupported<T>() -> std_io::Result<T> {
 }
 
 pub fn unsupported_err() -> std_io::Error {
-    std_io::Error::new_const(std_io::ErrorKind::Other, &"operation not supported on this platform")
+    std_io::Error::new_const(std_io::ErrorKind::NotSupported, &"operation not supported on this platform")
 }
 
 pub fn decode_error_kind(_code: i32) -> crate::io::ErrorKind {

library/std/src/sys/unsupported/os.rs

@@ -80,11 +80,11 @@ pub fn getenv(_: &OsStr) -> io::Result<Option<OsString>> {
 }
 
 pub fn setenv(_: &OsStr, _: &OsStr) -> io::Result<()> {
-    Err(io::Error::new_const(io::ErrorKind::Other, &"cannot set env vars on this platform"))
+    Err(io::Error::new_const(io::ErrorKind::NotSupported, &"cannot set env vars on this platform"))
 }
 
 pub fn unsetenv(_: &OsStr) -> io::Result<()> {
-    Err(io::Error::new_const(io::ErrorKind::Other, &"cannot unset env vars on this platform"))
+    Err(io::Error::new_const(io::ErrorKind::NotSupported, &"cannot unset env vars on this platform"))
 }
 
 pub fn temp_dir() -> PathBuf {

library/std/src/sys/windows/fs.rs

@@ -802,7 +802,7 @@ pub fn link(original: &Path, link: &Path) -> io::Result<()> {
 
 #[cfg(target_vendor = "uwp")]
 pub fn link(_original: &Path, _link: &Path) -> io::Result<()> {
-    return Err(io::Error::new_const(io::ErrorKind::Other, &"hard link are not supported on UWP"));
+    return Err(io::Error::new_const(io::ErrorKind::NotSupported, &"hard link are not supported on UWP"));
 }
 
 pub fn stat(path: &Path) -> io::Result<FileAttr> {

library/std/src/sys/windows/net.rs

@@ -370,7 +370,7 @@ impl Socket {
 
     #[cfg(target_vendor = "uwp")]
     fn set_no_inherit(&self) -> io::Result<()> {
-        Err(io::Error::new_const(io::ErrorKind::Other, &"Unavailable on UWP"))
+        Err(io::Error::new_const(io::ErrorKind::NotSupported, &"Unavailable on UWP"))
     }
 
     pub fn shutdown(&self, how: Shutdown) -> io::Result<()> {