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-rw-r--r--library/std/src/io/buffered/bufreader/buffer.rs2
-rw-r--r--library/std/src/io/buffered/bufwriter.rs4
-rw-r--r--library/std/src/io/cursor.rs4
-rw-r--r--library/std/src/io/error.rs67
-rw-r--r--library/std/src/io/error/tests.rs10
-rw-r--r--library/std/src/io/mod.rs7
-rw-r--r--library/std/src/io/tests.rs4
7 files changed, 57 insertions, 41 deletions
diff --git a/library/std/src/io/buffered/bufreader/buffer.rs b/library/std/src/io/buffered/bufreader/buffer.rs
index 52fe49985c6..17721090db5 100644
--- a/library/std/src/io/buffered/bufreader/buffer.rs
+++ b/library/std/src/io/buffered/bufreader/buffer.rs
@@ -41,7 +41,7 @@ impl Buffer {
         match Box::try_new_uninit_slice(capacity) {
             Ok(buf) => Ok(Self { buf, pos: 0, filled: 0, initialized: 0 }),
             Err(_) => {
-                Err(io::const_io_error!(ErrorKind::OutOfMemory, "failed to allocate read buffer"))
+                Err(io::const_error!(ErrorKind::OutOfMemory, "failed to allocate read buffer"))
             }
         }
     }
diff --git a/library/std/src/io/buffered/bufwriter.rs b/library/std/src/io/buffered/bufwriter.rs
index c41bae2aa4e..574eb83dc56 100644
--- a/library/std/src/io/buffered/bufwriter.rs
+++ b/library/std/src/io/buffered/bufwriter.rs
@@ -96,7 +96,7 @@ impl<W: Write> BufWriter<W> {
 
     pub(crate) fn try_new_buffer() -> io::Result<Vec<u8>> {
         Vec::try_with_capacity(DEFAULT_BUF_SIZE).map_err(|_| {
-            io::const_io_error!(ErrorKind::OutOfMemory, "failed to allocate write buffer")
+            io::const_error!(ErrorKind::OutOfMemory, "failed to allocate write buffer")
         })
     }
 
@@ -238,7 +238,7 @@ impl<W: ?Sized + Write> BufWriter<W> {
 
             match r {
                 Ok(0) => {
-                    return Err(io::const_io_error!(
+                    return Err(io::const_error!(
                         ErrorKind::WriteZero,
                         "failed to write the buffered data",
                     ));
diff --git a/library/std/src/io/cursor.rs b/library/std/src/io/cursor.rs
index fbfdb4fa023..b2ffeb0f95d 100644
--- a/library/std/src/io/cursor.rs
+++ b/library/std/src/io/cursor.rs
@@ -304,7 +304,7 @@ where
                 self.pos = n;
                 Ok(self.pos)
             }
-            None => Err(io::const_io_error!(
+            None => Err(io::const_error!(
                 ErrorKind::InvalidInput,
                 "invalid seek to a negative or overflowing position",
             )),
@@ -446,7 +446,7 @@ fn reserve_and_pad<A: Allocator>(
     buf_len: usize,
 ) -> io::Result<usize> {
     let pos: usize = (*pos_mut).try_into().map_err(|_| {
-        io::const_io_error!(
+        io::const_error!(
             ErrorKind::InvalidInput,
             "cursor position exceeds maximum possible vector length",
         )
diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs
index 5d7adcace52..03f38e220a5 100644
--- a/library/std/src/io/error.rs
+++ b/library/std/src/io/error.rs
@@ -76,31 +76,31 @@ impl fmt::Debug for Error {
 #[allow(dead_code)]
 impl Error {
     pub(crate) const INVALID_UTF8: Self =
-        const_io_error!(ErrorKind::InvalidData, "stream did not contain valid UTF-8");
+        const_error!(ErrorKind::InvalidData, "stream did not contain valid UTF-8");
 
     pub(crate) const READ_EXACT_EOF: Self =
-        const_io_error!(ErrorKind::UnexpectedEof, "failed to fill whole buffer");
+        const_error!(ErrorKind::UnexpectedEof, "failed to fill whole buffer");
 
-    pub(crate) const UNKNOWN_THREAD_COUNT: Self = const_io_error!(
+    pub(crate) const UNKNOWN_THREAD_COUNT: Self = const_error!(
         ErrorKind::NotFound,
         "The number of hardware threads is not known for the target platform"
     );
 
     pub(crate) const UNSUPPORTED_PLATFORM: Self =
-        const_io_error!(ErrorKind::Unsupported, "operation not supported on this platform");
+        const_error!(ErrorKind::Unsupported, "operation not supported on this platform");
 
     pub(crate) const WRITE_ALL_EOF: Self =
-        const_io_error!(ErrorKind::WriteZero, "failed to write whole buffer");
+        const_error!(ErrorKind::WriteZero, "failed to write whole buffer");
 
     pub(crate) const ZERO_TIMEOUT: Self =
-        const_io_error!(ErrorKind::InvalidInput, "cannot set a 0 duration timeout");
+        const_error!(ErrorKind::InvalidInput, "cannot set a 0 duration timeout");
 }
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl From<alloc::ffi::NulError> for Error {
     /// Converts a [`alloc::ffi::NulError`] into a [`Error`].
     fn from(_: alloc::ffi::NulError) -> Error {
-        const_io_error!(ErrorKind::InvalidInput, "data provided contains a nul byte")
+        const_error!(ErrorKind::InvalidInput, "data provided contains a nul byte")
     }
 }
 
@@ -151,27 +151,38 @@ pub type RawOsError = sys::RawOsError;
 // (For the sake of being explicit: the alignment requirement here only matters
 // if `error/repr_bitpacked.rs` is in use — for the unpacked repr it doesn't
 // matter at all)
+#[doc(hidden)]
+#[unstable(feature = "io_const_error_internals", issue = "none")]
 #[repr(align(4))]
 #[derive(Debug)]
-pub(crate) struct SimpleMessage {
-    kind: ErrorKind,
-    message: &'static str,
-}
-
-impl SimpleMessage {
-    pub(crate) const fn new(kind: ErrorKind, message: &'static str) -> Self {
-        Self { kind, message }
-    }
+pub struct SimpleMessage {
+    pub kind: ErrorKind,
+    pub message: &'static str,
 }
 
-/// Creates and returns an `io::Error` for a given `ErrorKind` and constant
-/// message. This doesn't allocate.
-pub(crate) macro const_io_error($kind:expr, $message:expr $(,)?) {
-    $crate::io::error::Error::from_static_message({
-        const MESSAGE_DATA: $crate::io::error::SimpleMessage =
-            $crate::io::error::SimpleMessage::new($kind, $message);
-        &MESSAGE_DATA
-    })
+/// Creates a new I/O error from a known kind of error and a string literal.
+///
+/// Contrary to [`Error::new`], this macro does not allocate and can be used in
+/// `const` contexts.
+///
+/// # Example
+/// ```
+/// #![feature(io_const_error)]
+/// use std::io::{const_error, Error, ErrorKind};
+///
+/// const FAIL: Error = const_error!(ErrorKind::Unsupported, "tried something that never works");
+///
+/// fn not_here() -> Result<(), Error> {
+///     Err(FAIL)
+/// }
+/// ```
+#[rustc_macro_transparency = "semitransparent"]
+#[unstable(feature = "io_const_error", issue = "133448")]
+#[allow_internal_unstable(hint_must_use, io_const_error_internals)]
+pub macro const_error($kind:expr, $message:expr $(,)?) {
+    $crate::hint::must_use($crate::io::Error::from_static_message(
+        const { &$crate::io::SimpleMessage { kind: $kind, message: $message } },
+    ))
 }
 
 // As with `SimpleMessage`: `#[repr(align(4))]` here is just because
@@ -592,13 +603,15 @@ impl Error {
     ///
     /// This function does not allocate.
     ///
-    /// You should not use this directly, and instead use the `const_io_error!`
-    /// macro: `io::const_io_error!(ErrorKind::Something, "some_message")`.
+    /// You should not use this directly, and instead use the `const_error!`
+    /// macro: `io::const_error!(ErrorKind::Something, "some_message")`.
     ///
     /// This function should maybe change to `from_static_message<const MSG: &'static
     /// str>(kind: ErrorKind)` in the future, when const generics allow that.
     #[inline]
-    pub(crate) const fn from_static_message(msg: &'static SimpleMessage) -> Error {
+    #[doc(hidden)]
+    #[unstable(feature = "io_const_error_internals", issue = "none")]
+    pub const fn from_static_message(msg: &'static SimpleMessage) -> Error {
         Self { repr: Repr::new_simple_message(msg) }
     }
 
diff --git a/library/std/src/io/error/tests.rs b/library/std/src/io/error/tests.rs
index 00d04984a38..edac6563478 100644
--- a/library/std/src/io/error/tests.rs
+++ b/library/std/src/io/error/tests.rs
@@ -1,4 +1,4 @@
-use super::{Custom, Error, ErrorData, ErrorKind, Repr, SimpleMessage, const_io_error};
+use super::{Custom, Error, ErrorData, ErrorKind, Repr, SimpleMessage, const_error};
 use crate::assert_matches::assert_matches;
 use crate::mem::size_of;
 use crate::sys::decode_error_kind;
@@ -60,7 +60,7 @@ fn test_downcasting() {
 
 #[test]
 fn test_const() {
-    const E: Error = const_io_error!(ErrorKind::NotFound, "hello");
+    const E: Error = const_error!(ErrorKind::NotFound, "hello");
 
     assert_eq!(E.kind(), ErrorKind::NotFound);
     assert_eq!(E.to_string(), "hello");
@@ -110,13 +110,13 @@ fn test_simple_message_packing() {
         }};
     }
 
-    let not_static = const_io_error!(Uncategorized, "not a constant!");
+    let not_static = const_error!(Uncategorized, "not a constant!");
     check_simple_msg!(not_static, Uncategorized, "not a constant!");
 
-    const CONST: Error = const_io_error!(NotFound, "definitely a constant!");
+    const CONST: Error = const_error!(NotFound, "definitely a constant!");
     check_simple_msg!(CONST, NotFound, "definitely a constant!");
 
-    static STATIC: Error = const_io_error!(BrokenPipe, "a constant, sort of!");
+    static STATIC: Error = const_error!(BrokenPipe, "a constant, sort of!");
     check_simple_msg!(STATIC, BrokenPipe, "a constant, sort of!");
 }
 
diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index 21e70774954..4ffb0463006 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -301,12 +301,15 @@ mod tests;
 pub use core::io::{BorrowedBuf, BorrowedCursor};
 use core::slice::memchr;
 
-pub(crate) use error::const_io_error;
-
 #[stable(feature = "bufwriter_into_parts", since = "1.56.0")]
 pub use self::buffered::WriterPanicked;
 #[unstable(feature = "raw_os_error_ty", issue = "107792")]
 pub use self::error::RawOsError;
+#[doc(hidden)]
+#[unstable(feature = "io_const_error_internals", issue = "none")]
+pub use self::error::SimpleMessage;
+#[unstable(feature = "io_const_error", issue = "133448")]
+pub use self::error::const_error;
 #[stable(feature = "is_terminal", since = "1.70.0")]
 pub use self::stdio::IsTerminal;
 pub(crate) use self::stdio::attempt_print_to_stderr;
diff --git a/library/std/src/io/tests.rs b/library/std/src/io/tests.rs
index 89e806c0891..47cbb9614af 100644
--- a/library/std/src/io/tests.rs
+++ b/library/std/src/io/tests.rs
@@ -225,12 +225,12 @@ fn take_eof() {
 
     impl Read for R {
         fn read(&mut self, _: &mut [u8]) -> io::Result<usize> {
-            Err(io::const_io_error!(io::ErrorKind::Other, ""))
+            Err(io::const_error!(io::ErrorKind::Other, ""))
         }
     }
     impl BufRead for R {
         fn fill_buf(&mut self) -> io::Result<&[u8]> {
-            Err(io::const_io_error!(io::ErrorKind::Other, ""))
+            Err(io::const_error!(io::ErrorKind::Other, ""))
         }
         fn consume(&mut self, _amt: usize) {}
     }
generated by cgit-pink 1.4.1-3-g733a5 (git 2.37.1) at 2025-11-03 11:02:24 +0000