[INFO] cloning repository https://github.com/Undin/check-rustc-version
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Undin/check-rustc-version" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUndin%2Fcheck-rustc-version", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUndin%2Fcheck-rustc-version'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 654ef80d5b53f30f04d71016277543e87e898ef3
[INFO] documenting Undin/check-rustc-version against 1.75.0 for beta-1.76-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUndin%2Fcheck-rustc-version" "/workspace/builds/worker-3-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Undin/check-rustc-version on toolchain 1.75.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.75.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Undin/check-rustc-version
[INFO] finished tweaking git repo https://github.com/Undin/check-rustc-version
[INFO] tweaked toml for git repo https://github.com/Undin/check-rustc-version written to /workspace/builds/worker-3-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/Undin/check-rustc-version 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" "+1.75.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/source:/opt/rustwide/workdir:ro,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" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+1.75.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6aa99bd832115c51ee47bf70cb6ffbf8270c651e1022a8cb987433624c5b0a38
[INFO] running `Command { std: "docker" "start" "-a" "6aa99bd832115c51ee47bf70cb6ffbf8270c651e1022a8cb987433624c5b0a38", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6aa99bd832115c51ee47bf70cb6ffbf8270c651e1022a8cb987433624c5b0a38", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6aa99bd832115c51ee47bf70cb6ffbf8270c651e1022a8cb987433624c5b0a38", kill_on_drop: false }`
[INFO] [stdout] 6aa99bd832115c51ee47bf70cb6ffbf8270c651e1022a8cb987433624c5b0a38
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/source:/opt/rustwide/workdir:ro,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" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+1.75.0" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b495124866749f07bd265cbdce989fc0c1e9aab768730872be1dd3ec96acd8c9
[INFO] running `Command { std: "docker" "start" "-a" "b495124866749f07bd265cbdce989fc0c1e9aab768730872be1dd3ec96acd8c9", kill_on_drop: false }`
[INFO] [stderr]    Compiling check-rustc-version v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> build.rs:16:5
[INFO] [stdout]    |
[INFO] [stdout] 16 |     write!(&mut file, "RUSTC: {}\n", env::var_os("RUSTC").unwrap().to_string_lossy());
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> build.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     write!(&mut file, "rustc --version: {}\n", version);
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: failed to run custom build command for `check-rustc-version v0.1.0 (/opt/rustwide/workdir)`
[INFO] [stderr] note: To improve backtraces for build dependencies, set the CARGO_PROFILE_DEV_BUILD_OVERRIDE_DEBUG=true environment variable to enable debug information generation.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `/opt/rustwide/target/debug/build/check-rustc-version-55739a7b134ca3ec/build-script-build` (exit status: 101)
[INFO] [stderr]   --- stderr
[INFO] [stderr]   thread 'main' panicked at build.rs:15:54:
[INFO] [stderr]   called `Result::unwrap()` on an `Err` value: Os { code: 30, kind: ReadOnlyFilesystem, message: "Read-only file system" }
[INFO] [stderr]   stack backtrace:
[INFO] [stderr]      0:     0x556bc73161ec - std::backtrace_rs::backtrace::libunwind::trace::ha637c64ce894333a
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
[INFO] [stderr]      1:     0x556bc73161ec - std::backtrace_rs::backtrace::trace_unsynchronized::h47f62dea28e0c88d
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
[INFO] [stderr]      2:     0x556bc73161ec - std::sys_common::backtrace::_print_fmt::h9eef0abe20ede486
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/sys_common/backtrace.rs:67:5
[INFO] [stderr]      3:     0x556bc73161ec - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::hed7f999df88cc644
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/sys_common/backtrace.rs:44:22
[INFO] [stderr]      4:     0x556bc73393e0 - core::fmt::rt::Argument::fmt::h1539a9308b8d058d
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/core/src/fmt/rt.rs:142:9
[INFO] [stderr]      5:     0x556bc73393e0 - core::fmt::write::h3a39390d8560d9c9
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/core/src/fmt/mod.rs:1120:17
[INFO] [stderr]      6:     0x556bc731426f - std::io::Write::write_fmt::h5fc9997dfe05f882
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/io/mod.rs:1762:15
[INFO] [stderr]      7:     0x556bc7315fd4 - std::sys_common::backtrace::_print::h894006fb5c6f3d45
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/sys_common/backtrace.rs:47:5
[INFO] [stderr]      8:     0x556bc7315fd4 - std::sys_common::backtrace::print::h23a2d212c6fff936
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/sys_common/backtrace.rs:34:9
[INFO] [stderr]      9:     0x556bc73174e7 - std::panicking::default_hook::{{closure}}::h8a1d2ee00185001a
[INFO] [stderr]     10:     0x556bc731724f - std::panicking::default_hook::h6038f2eba384e475
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/panicking.rs:292:9
[INFO] [stderr]     11:     0x556bc7317968 - std::panicking::rust_panic_with_hook::h2b5517d590cab22e
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/panicking.rs:779:13
[INFO] [stderr]     12:     0x556bc731784e - std::panicking::begin_panic_handler::{{closure}}::h233112c06e0ef43e
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/panicking.rs:657:13
[INFO] [stderr]     13:     0x556bc73166b6 - std::sys_common::backtrace::__rust_end_short_backtrace::h6e893f24d7ebbff8
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/sys_common/backtrace.rs:170:18
[INFO] [stderr]     14:     0x556bc73175b2 - rust_begin_unwind
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/panicking.rs:645:5
[INFO] [stderr]     15:     0x556bc72f2f05 - core::panicking::panic_fmt::hbf0e066aabfa482c
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/core/src/panicking.rs:72:14
[INFO] [stderr]     16:     0x556bc72f3363 - core::result::unwrap_failed::hddb4fea594200c52
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/core/src/result.rs:1653:5
[INFO] [stderr]     17:     0x556bc72f5944 - core::result::Result<T,E>::unwrap::h84337d5a5a2dd35d
[INFO] [stderr]     18:     0x556bc72f7857 - build_script_build::extract_rustc_version::h9a56198c7037f055
[INFO] [stderr]     19:     0x556bc72f7706 - build_script_build::main::hfd64e6fa42376318
[INFO] [stderr]     20:     0x556bc72f4ac3 - core::ops::function::FnOnce::call_once::hd1c552290e3c40b3
[INFO] [stderr]     21:     0x556bc72f3af6 - std::sys_common::backtrace::__rust_begin_short_backtrace::he303f1ca66898e95
[INFO] [stderr]     22:     0x556bc72f45e9 - std::rt::lang_start::{{closure}}::hd15d6b2a10feb0c7
[INFO] [stderr]     23:     0x556bc73116d7 - core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::hd95060ecd5e1ca24
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/core/src/ops/function.rs:284:13
[INFO] [stderr]     24:     0x556bc73116d7 - std::panicking::try::do_call::h6e8cf51db32a6e4b
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/panicking.rs:552:40
[INFO] [stderr]     25:     0x556bc73116d7 - std::panicking::try::h3a52eefe24fe3c29
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/panicking.rs:516:19
[INFO] [stderr]     26:     0x556bc73116d7 - std::panic::catch_unwind::h24c28c23c02c3841
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/panic.rs:142:14
[INFO] [stderr]     27:     0x556bc73116d7 - std::rt::lang_start_internal::{{closure}}::h705d3c9cbc06ef47
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/rt.rs:148:48
[INFO] [stderr]     28:     0x556bc73116d7 - std::panicking::try::do_call::ha21f52ba13158470
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/panicking.rs:552:40
[INFO] [stderr]     29:     0x556bc73116d7 - std::panicking::try::h5581346bf6aeb1f8
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/panicking.rs:516:19
[INFO] [stderr]     30:     0x556bc73116d7 - std::panic::catch_unwind::h7919645a6b72e25b
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/panic.rs:142:14
[INFO] [stderr]     31:     0x556bc73116d7 - std::rt::lang_start_internal::h12de51168669836e
[INFO] [stderr]                                  at /rustc/82e1608dfa6e0b5569232559e3d385fea5a93112/library/std/src/rt.rs:148:20
[INFO] [stderr]     32:     0x556bc72f45c7 - std::rt::lang_start::hc2e2c689db1fd349
[INFO] [stderr]     33:     0x556bc72f7b95 - main
[INFO] [stderr]     34:     0x7fb26b18ed90 - <unknown>
[INFO] [stderr]     35:     0x7fb26b18ee40 - __libc_start_main
[INFO] [stderr]     36:     0x556bc72f3625 - _start
[INFO] [stderr]     37:                0x0 - <unknown>
[INFO] running `Command { std: "docker" "inspect" "b495124866749f07bd265cbdce989fc0c1e9aab768730872be1dd3ec96acd8c9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b495124866749f07bd265cbdce989fc0c1e9aab768730872be1dd3ec96acd8c9", kill_on_drop: false }`
[INFO] [stdout] b495124866749f07bd265cbdce989fc0c1e9aab768730872be1dd3ec96acd8c9
[INFO] documenting Undin/check-rustc-version against beta-2023-12-22 for beta-1.76-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FUndin%2Fcheck-rustc-version" "/workspace/builds/worker-3-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Undin/check-rustc-version on toolchain beta-2023-12-22
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2023-12-22" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Undin/check-rustc-version
[INFO] finished tweaking git repo https://github.com/Undin/check-rustc-version
[INFO] tweaked toml for git repo https://github.com/Undin/check-rustc-version written to /workspace/builds/worker-3-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/Undin/check-rustc-version 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" "+beta-2023-12-22" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/source:/opt/rustwide/workdir:ro,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" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2023-12-22" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 511d57848c7f401faadb7ebd15a214639ed08a69bfac61ac5f32f4c3183312d7
[INFO] running `Command { std: "docker" "start" "-a" "511d57848c7f401faadb7ebd15a214639ed08a69bfac61ac5f32f4c3183312d7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "511d57848c7f401faadb7ebd15a214639ed08a69bfac61ac5f32f4c3183312d7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "511d57848c7f401faadb7ebd15a214639ed08a69bfac61ac5f32f4c3183312d7", kill_on_drop: false }`
[INFO] [stdout] 511d57848c7f401faadb7ebd15a214639ed08a69bfac61ac5f32f4c3183312d7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/source:/opt/rustwide/workdir:ro,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" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2023-12-22" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f29a17fa7da163b41c5c4bf1d2e28f392ae572a332fda942b32011f831fc0f32
[INFO] running `Command { std: "docker" "start" "-a" "f29a17fa7da163b41c5c4bf1d2e28f392ae572a332fda942b32011f831fc0f32", kill_on_drop: false }`
[INFO] [stderr]    Compiling check-rustc-version v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> build.rs:16:5
[INFO] [stdout]    |
[INFO] [stdout] 16 |     write!(&mut file, "RUSTC: {}\n", env::var_os("RUSTC").unwrap().to_string_lossy());
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> build.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     write!(&mut file, "rustc --version: {}\n", version);
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]    = note: this warning originates in the macro `write` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: failed to run custom build command for `check-rustc-version v0.1.0 (/opt/rustwide/workdir)`
[INFO] [stderr] note: To improve backtraces for build dependencies, set the CARGO_PROFILE_DEV_BUILD_OVERRIDE_DEBUG=true environment variable to enable debug information generation.
[INFO] [stderr] 
[INFO] [stderr] Caused by:
[INFO] [stderr]   process didn't exit successfully: `/opt/rustwide/target/debug/build/check-rustc-version-af25273abe42475e/build-script-build` (exit status: 101)
[INFO] [stderr]   --- stderr
[INFO] [stderr]   thread 'main' panicked at build.rs:15:54:
[INFO] [stderr]   called `Result::unwrap()` on an `Err` value: Os { code: 30, kind: ReadOnlyFilesystem, message: "Read-only file system" }
[INFO] [stderr]   stack backtrace:
[INFO] [stderr]      0:     0x5591378c3426 - std::backtrace_rs::backtrace::libunwind::trace::h261606ad26a499c1
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/../../backtrace/src/backtrace/libunwind.rs:104:5
[INFO] [stderr]      1:     0x5591378c3426 - std::backtrace_rs::backtrace::trace_unsynchronized::hd183f0625477fb28
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/../../backtrace/src/backtrace/mod.rs:66:5
[INFO] [stderr]      2:     0x5591378c3426 - std::sys_common::backtrace::_print_fmt::hd7f8fef21b4eda67
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/sys_common/backtrace.rs:68:5
[INFO] [stderr]      3:     0x5591378c3426 - <std::sys_common::backtrace::_print::DisplayBacktrace as core::fmt::Display>::fmt::h623d9b51f2f453f1
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/sys_common/backtrace.rs:44:22
[INFO] [stderr]      4:     0x5591378e5930 - core::fmt::rt::Argument::fmt::h9f417ac76a86f368
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/core/src/fmt/rt.rs:142:9
[INFO] [stderr]      5:     0x5591378e5930 - core::fmt::write::hc9b6faf4ac2aeff7
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/core/src/fmt/mod.rs:1120:17
[INFO] [stderr]      6:     0x5591378c152f - std::io::Write::write_fmt::hfead1eee52c2e65e
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/io/mod.rs:1810:15
[INFO] [stderr]      7:     0x5591378c3204 - std::sys_common::backtrace::_print::hd5d66399c7df88a2
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/sys_common/backtrace.rs:47:5
[INFO] [stderr]      8:     0x5591378c3204 - std::sys_common::backtrace::print::he81ed2da642d37e5
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/sys_common/backtrace.rs:34:9
[INFO] [stderr]      9:     0x5591378c4767 - std::panicking::default_hook::{{closure}}::h85773f4fa117163d
[INFO] [stderr]     10:     0x5591378c44c9 - std::panicking::default_hook::h6a1694a91d09b278
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/panicking.rs:292:9
[INFO] [stderr]     11:     0x5591378c4bf8 - std::panicking::rust_panic_with_hook::h0a7ad96e90f7145b
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/panicking.rs:779:13
[INFO] [stderr]     12:     0x5591378c4ad2 - std::panicking::begin_panic_handler::{{closure}}::h7919090525c6485e
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/panicking.rs:657:13
[INFO] [stderr]     13:     0x5591378c3926 - std::sys_common::backtrace::__rust_end_short_backtrace::hf3289479464f7dfe
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/sys_common/backtrace.rs:171:18
[INFO] [stderr]     14:     0x5591378c4830 - rust_begin_unwind
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/panicking.rs:645:5
[INFO] [stderr]     15:     0x55913789ff05 - core::panicking::panic_fmt::hcc9f77c5c132af55
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/core/src/panicking.rs:72:14
[INFO] [stderr]     16:     0x5591378a0373 - core::result::unwrap_failed::hbe14f498be1452f9
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/core/src/result.rs:1649:5
[INFO] [stderr]     17:     0x5591378a28f4 - core::result::Result<T,E>::unwrap::he8ad9a48de72b180
[INFO] [stderr]     18:     0x5591378a4877 - build_script_build::extract_rustc_version::ha2accc24e75e3380
[INFO] [stderr]     19:     0x5591378a4726 - build_script_build::main::h700992151981128d
[INFO] [stderr]     20:     0x5591378a1a53 - core::ops::function::FnOnce::call_once::h0a1f779baeb31d38
[INFO] [stderr]     21:     0x5591378a0b06 - std::sys_common::backtrace::__rust_begin_short_backtrace::h990c3abac48d5d0c
[INFO] [stderr]     22:     0x5591378a15c9 - std::rt::lang_start::{{closure}}::h08e1551ee259e292
[INFO] [stderr]     23:     0x5591378be721 - core::ops::function::impls::<impl core::ops::function::FnOnce<A> for &F>::call_once::h4eb4c5e1620f29b0
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/core/src/ops/function.rs:284:13
[INFO] [stderr]     24:     0x5591378be721 - std::panicking::try::do_call::h73fd26535faffcdf
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/panicking.rs:552:40
[INFO] [stderr]     25:     0x5591378be721 - std::panicking::try::h77ff1d98f0fb9f39
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/panicking.rs:516:19
[INFO] [stderr]     26:     0x5591378be721 - std::panic::catch_unwind::hab3caf2448b95e37
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/panic.rs:142:14
[INFO] [stderr]     27:     0x5591378be721 - std::rt::lang_start_internal::{{closure}}::h8086711f9c783f78
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/rt.rs:148:48
[INFO] [stderr]     28:     0x5591378be721 - std::panicking::try::do_call::hf920d4dc291cd6ca
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/panicking.rs:552:40
[INFO] [stderr]     29:     0x5591378be721 - std::panicking::try::h2b806ccc0a85db74
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/panicking.rs:516:19
[INFO] [stderr]     30:     0x5591378be721 - std::panic::catch_unwind::h038489539c507df2
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/panic.rs:142:14
[INFO] [stderr]     31:     0x5591378be721 - std::rt::lang_start_internal::h28503b88912e8a5c
[INFO] [stderr]                                  at /rustc/0e09125c6c3c2fd70d7de961bcf0e51575235fad/library/std/src/rt.rs:148:20
[INFO] [stderr]     32:     0x5591378a15a7 - std::rt::lang_start::h2845cb535505e6ea
[INFO] [stderr]     33:     0x5591378a4bb5 - main
[INFO] [stderr]     34:     0x7f4e56b93d90 - <unknown>
[INFO] [stderr]     35:     0x7f4e56b93e40 - __libc_start_main
[INFO] [stderr]     36:     0x5591378a0635 - _start
[INFO] [stderr]     37:                0x0 - <unknown>
[INFO] running `Command { std: "docker" "inspect" "f29a17fa7da163b41c5c4bf1d2e28f392ae572a332fda942b32011f831fc0f32", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f29a17fa7da163b41c5c4bf1d2e28f392ae572a332fda942b32011f831fc0f32", kill_on_drop: false }`
[INFO] [stdout] f29a17fa7da163b41c5c4bf1d2e28f392ae572a332fda942b32011f831fc0f32
