[INFO] fetching crate io_core 0.4.4...
[INFO] fixing io_core-0.4.4 against try#622891a4e29178280638a6b63a8908bde2c0c854+cargoflags=-Zfix-edition=start=2015 for pr-157817-2
[INFO] extracting crate io_core 0.4.4 into /workspace/builds/worker-4-tc1/source
[INFO] started tweaking crates.io crate io_core 0.4.4
[INFO] finished tweaking crates.io crate io_core 0.4.4
[INFO] tweaked toml for crates.io crate io_core 0.4.4 written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate io_core 0.4.4 on toolchain 622891a4e29178280638a6b63a8908bde2c0c854
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+622891a4e29178280638a6b63a8908bde2c0c854" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate crates.io crate io_core 0.4.4 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+622891a4e29178280638a6b63a8908bde2c0c854" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/source:/opt/rustwide/workdir:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3a6becf2bc8dde7f3fa57ede90e4f284e72d296796fc446bbb1e2c7cc0530151" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] 2fb7e7e200cb66c2f0ba138643b19c33201c5aeb967bc9d5e920becdbde508f0
[INFO] running `Command { std: "docker" "start" "2fb7e7e200cb66c2f0ba138643b19c33201c5aeb967bc9d5e920becdbde508f0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "2fb7e7e200cb66c2f0ba138643b19c33201c5aeb967bc9d5e920becdbde508f0" "/opt/rustwide/cargo-home/bin/cargo" "+622891a4e29178280638a6b63a8908bde2c0c854" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2fb7e7e200cb66c2f0ba138643b19c33201c5aeb967bc9d5e920becdbde508f0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=" "-e" "RUSTDOCFLAGS=" "-w" "/opt/rustwide/workdir" "--user" "0:0" "2fb7e7e200cb66c2f0ba138643b19c33201c5aeb967bc9d5e920becdbde508f0" "/opt/rustwide/cargo-home/bin/cargo" "+622891a4e29178280638a6b63a8908bde2c0c854" "fix" "--allow-no-vcs" "--allow-dirty" "--frozen" "--all" "--all-targets" "--message-format=json" "-Zfix-edition=start=2015", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.185
[INFO] [stderr]     Checking memchr v2.8.0
[INFO] [stderr]     Checking io_core v0.4.4 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0432]: unresolved import `crate::sys::io::error_string`
[INFO] [stdout]  --> src/io/error/tests.rs:6:41
[INFO] [stdout]   |
[INFO] [stdout] 6 | use crate::sys::io::{decode_error_kind, error_string};
[INFO] [stdout]   |                                         ^^^^^^^^^^^^ no `error_string` in `sys::io`
[INFO] [stdout]   |
[INFO] [stdout] note: found an item that was configured out
[INFO] [stdout]  --> src/sys/io/mod.rs:5:16
[INFO] [stdout]   |
[INFO] [stdout] 4 | #[cfg(feature = "alloc")]
[INFO] [stdout]   |       ----------------- the item is gated behind the `alloc` feature
[INFO] [stdout] 5 | pub use error::error_string;
[INFO] [stdout]   |                ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: specialization is experimental
[INFO] [stdout]     --> src/io/mod.rs:2911:5
[INFO] [stdout]      |
[INFO] [stdout] 2911 |     default fn spec_read_byte(&mut self) -> Option<Result<u8>> {
[INFO] [stdout]      |     ^^^^^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout]      = help: add `#![feature(specialization)]` to the crate attributes to enable
[INFO] [stdout]      = note: this compiler was built on 2026-06-16; consider upgrading it if it is out of date
[INFO] [stdout]      = warning: unstable syntax can change at any point in the future, causing a hard error!
[INFO] [stdout]      = note: for more information, see issue #154045 <https://github.com/rust-lang/rust/issues/154045>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: specialization is experimental
[INFO] [stdout]     --> src/io/mod.rs:2953:5
[INFO] [stdout]      |
[INFO] [stdout] 2953 |     default fn lower_bound(&self) -> usize {
[INFO] [stdout]      |     ^^^^^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout]      = help: add `#![feature(specialization)]` to the crate attributes to enable
[INFO] [stdout]      = note: this compiler was built on 2026-06-16; consider upgrading it if it is out of date
[INFO] [stdout]      = warning: unstable syntax can change at any point in the future, causing a hard error!
[INFO] [stdout]      = note: for more information, see issue #154045 <https://github.com/rust-lang/rust/issues/154045>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: specialization is experimental
[INFO] [stdout]     --> src/io/mod.rs:2958:5
[INFO] [stdout]      |
[INFO] [stdout] 2958 |     default fn upper_bound(&self) -> Option<usize> {
[INFO] [stdout]      |     ^^^^^^^
[INFO] [stdout]      |
[INFO] [stdout]      = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout]      = help: add `#![feature(specialization)]` to the crate attributes to enable
[INFO] [stdout]      = note: this compiler was built on 2026-06-16; consider upgrading it if it is out of date
[INFO] [stdout]      = warning: unstable syntax can change at any point in the future, causing a hard error!
[INFO] [stdout]      = note: for more information, see issue #154045 <https://github.com/rust-lang/rust/issues/154045>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0432`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `io_core` (lib test) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "2fb7e7e200cb66c2f0ba138643b19c33201c5aeb967bc9d5e920becdbde508f0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2fb7e7e200cb66c2f0ba138643b19c33201c5aeb967bc9d5e920becdbde508f0", kill_on_drop: false }`
[INFO] [stdout] 2fb7e7e200cb66c2f0ba138643b19c33201c5aeb967bc9d5e920becdbde508f0
