[Experiment]: Test EII for RawOsError in core

library/core/src/io/error.rs

@@ -2,6 +2,32 @@
 
 use crate::fmt;
 
+#[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+#[doc(hidden)]
+pub mod raw_os_error {
+    #![expect(dead_code)]
+
+    use super::{ErrorKind, RawOsError};
+
+    #[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+    #[eii]
+    pub fn decode_error_kind(_: RawOsError) -> ErrorKind {
+        ErrorKind::Uncategorized
+    }
+
+    #[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+    #[eii]
+    pub fn fmt(errno: RawOsError, fmt: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        <ErrorKind as core::fmt::Display>::fmt(&decode_error_kind(errno), fmt)
+    }
+
+    #[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+    #[eii]
+    pub fn is_interrupted(errno: RawOsError) -> bool {
+        matches!(decode_error_kind(errno), ErrorKind::Interrupted)
+    }
+}
+
 /// The type of raw OS error codes.
 ///
 /// This is an [`i32`] on all currently supported platforms, but platforms

library/core/src/io/mod.rs

@@ -14,6 +14,9 @@ pub use self::cursor::Cursor;
 pub use self::error::ErrorKind;
 #[unstable(feature = "raw_os_error_ty", issue = "107792")]
 pub use self::error::RawOsError;
+#[doc(hidden)]
+#[unstable(feature = "core_io_internals", reason = "exposed only for libstd", issue = "none")]
+pub use self::error::raw_os_error;
 #[unstable(feature = "core_io", issue = "154046")]
 pub use self::io_slice::{IoSlice, IoSliceMut};
 #[unstable(feature = "core_io", issue = "154046")]

library/core/src/lib.rs

@@ -134,6 +134,7 @@
 #![feature(diagnostic_on_unmatched_args)]
 #![feature(doc_cfg)]
 #![feature(doc_notable_trait)]
+#![feature(extern_item_impls)]
 #![feature(extern_types)]
 #![feature(f16)]
 #![feature(f128)]

library/std/src/io/error.rs

@@ -6,6 +6,24 @@ pub use core::io::ErrorKind;
 #[unstable(feature = "raw_os_error_ty", issue = "107792")]
 pub use core::io::RawOsError;
 
+#[cfg(not(test))]
+#[core::io::raw_os_error::decode_error_kind]
+fn raw_os_error_decode(code: RawOsError) -> ErrorKind {
+    sys::io::decode_error_kind(code)
+}
+
+#[cfg(not(test))]
+#[core::io::raw_os_error::fmt]
+fn raw_os_error_fmt(code: RawOsError, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
+    fmt.write_str(&sys::io::error_string(code))
+}
+
+#[cfg(not(test))]
+#[core::io::raw_os_error::is_interrupted]
+fn raw_os_error_is_interrupted(code: RawOsError) -> bool {
+    sys::io::is_interrupted(code)
+}
+
 // On 64-bit platforms, `io::Error` may use a bit-packed representation to
 // reduce size. However, this representation assumes that error codes are
 // always 32-bit wide.

src/ci/github-actions/jobs.yml

@@ -129,7 +129,7 @@ pr:
     <<: *job-linux-4c
   - name: x86_64-gnu-llvm-21
     env:
-      ENABLE_GCC_CODEGEN: "1"
+      # ENABLE_GCC_CODEGEN: "1"
       DOCKER_SCRIPT: x86_64-gnu-llvm.sh
     <<: *job-linux-4c
   - name: aarch64-gnu-llvm-21-1
@@ -146,17 +146,17 @@ pr:
     <<: *job-linux-4c
   - name: x86_64-gnu-miri
     <<: *job-linux-4c
-  - name: x86_64-gnu-gcc
-    doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
-    env:
-      CODEGEN_BACKENDS: llvm,gcc
-    <<: *job-linux-4c
-  - name: x86_64-gnu-gcc-core-tests
-    doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
-    env:
-      CODEGEN_BACKENDS: gcc
-    <<: *job-linux-4c
-  
+  # - name: x86_64-gnu-gcc
+  #   doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
+  #   env:
+  #     CODEGEN_BACKENDS: llvm,gcc
+  #   <<: *job-linux-4c
+  # - name: x86_64-gnu-gcc-core-tests
+  #   doc_url: https://rustc-dev-guide.rust-lang.org/tests/codegen-backend-tests/cg_gcc.html
+  #   env:
+  #     CODEGEN_BACKENDS: gcc
+  #   <<: *job-linux-4c
+
   # This job tests features we want to stabilize soon, to ensure they don't
   # regress.
   - name: x86_64-gnu-pre-stabilization

tests/ui/eii/io_in_core_no_std.rs

@@ -0,0 +1,20 @@
+//! Check that dynamic libraries can link and run now that there is an unconditional use
+//! of EII in `core`.
+
+//@ build-pass
+//@ compile-flags: -Cpanic=abort
+//@ no-prefer-dynamic
+//@ needs-crate-type: dylib
+#![crate_type = "dylib"]
+#![feature(core_io_internals)]
+#![feature(core_io)]
+#![feature(raw_os_error_ty)]
+#![no_std]
+#![no_implicit_prelude]
+
+#[panic_handler]
+fn panic_handler(_info: &core::panic::PanicInfo<'_>) -> ! {
+    loop {}
+}
+
+pub use core::io::raw_os_error::*;

tests/ui/eii/io_in_core_with_std.rs

@@ -0,0 +1,17 @@
+//! Check that `no_std` dynamic libraries can link and run without depending on `libstd`
+//! now that there is an unconditional use of EII in `core`.
+
+//@ build-pass
+//@ compile-flags: -Cpanic=abort
+//@ no-prefer-dynamic
+//@ needs-crate-type: dylib
+#![crate_type = "dylib"]
+#![feature(core_io_internals)]
+#![feature(core_io)]
+#![feature(raw_os_error_ty)]
+#![no_std]
+#![no_implicit_prelude]
+
+extern crate std;
+
+pub use core::io::raw_os_error::*;