[INFO] cloning repository https://github.com/systemctl603/rust_os
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/systemctl603/rust_os" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsystemctl603%2Frust_os", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsystemctl603%2Frust_os'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] becd1dd7cc5930efa061291a629efb56caff5353
[INFO] building systemctl603/rust_os against master#11663cd3bfefef7d34e8f0892c250bf698049392+rustflags=-Dtail-expr-drop-order for pr-134523
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsystemctl603%2Frust_os" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/systemctl603/rust_os on toolchain 11663cd3bfefef7d34e8f0892c250bf698049392
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-0-tc1/source/.cargo/config.toml
[INFO] started tweaking git repo https://github.com/systemctl603/rust_os
[INFO] finished tweaking git repo https://github.com/systemctl603/rust_os
[INFO] tweaked toml for git repo https://github.com/systemctl603/rust_os written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/systemctl603/rust_os 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" "+11663cd3bfefef7d34e8f0892c250bf698049392" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1b3bd156aa68862bf1e9589d78ef30871172818c2a66b96c5b1a04118e0b3779
[INFO] running `Command { std: "docker" "start" "-a" "1b3bd156aa68862bf1e9589d78ef30871172818c2a66b96c5b1a04118e0b3779", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1b3bd156aa68862bf1e9589d78ef30871172818c2a66b96c5b1a04118e0b3779", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1b3bd156aa68862bf1e9589d78ef30871172818c2a66b96c5b1a04118e0b3779", kill_on_drop: false }`
[INFO] [stdout] 1b3bd156aa68862bf1e9589d78ef30871172818c2a66b96c5b1a04118e0b3779
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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=forbid -Dtail-expr-drop-order" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 0f1762ae0a2e38d5f3d4cbe97bb1d0d78e8f97f13517ae522b8879394f4da5b5
[INFO] running `Command { std: "docker" "start" "-a" "0f1762ae0a2e38d5f3d4cbe97bb1d0d78e8f97f13517ae522b8879394f4da5b5", kill_on_drop: false }`
[INFO] [stderr]    Compiling bootloader v0.9.22
[INFO] [stderr]    Compiling spin v0.5.2
[INFO] [stderr]    Compiling volatile v0.2.7
[INFO] [stderr]    Compiling lazy_static v1.4.0
[INFO] [stderr]    Compiling rust_os v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `lazy_static::lazy_static`
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use lazy_static::lazy_static;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> src/main.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     panic!("Panic message");
[INFO] [stdout]    |     ----------------------- any code following this expression is unreachable
[INFO] [stdout] 11 |     loop {}
[INFO] [stdout]    |     ^^^^^^^ unreachable expression
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Write`
[INFO] [stdout]  --> src/vga_buffer.rs:1:23
[INFO] [stdout]   |
[INFO] [stdout] 1 | use core::fmt::{self, Write};
[INFO] [stdout]   |                       ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: linking with `cc` failed: exit status: 1
[INFO] [stdout]   |
[INFO] [stdout]   = note: LC_ALL="C" PATH="/opt/rustwide/rustup-home/toolchains/11663cd3bfefef7d34e8f0892c250bf698049392/lib/rustlib/x86_64-unknown-linux-gnu/bin:/opt/rustwide/rustup-home/toolchains/11663cd3bfefef7d34e8f0892c250bf698049392/lib/rustlib/x86_64-unknown-linux-gnu/bin/self-contained:/opt/rustwide/cargo-home/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" VSLANG="1033" "cc" "-m64" "/tmp/rustcWYcg1M/symbols.o" "<1 object files omitted>" "-Wl,--as-needed" "-Wl,-Bstatic" "/opt/rustwide/target/debug/deps/{libvolatile-cb94cadd0ac9ebce.rlib,liblazy_static-96b63743205dda33.rlib,libspin-c783243e56532085.rlib}" "/opt/rustwide/rustup-home/toolchains/11663cd3bfefef7d34e8f0892c250bf698049392/lib/rustlib/x86_64-unknown-linux-gnu/lib/{librustc_std_workspace_core-395a38b8e0851c9b.rlib,libcore-d453bab70303062c.rlib,libcompiler_builtins-d643a4794e0b0ebc.rlib}" "-Wl,-Bdynamic" "-B/opt/rustwide/rustup-home/toolchains/11663cd3bfefef7d34e8f0892c250bf698049392/lib/rustlib/x86_64-unknown-linux-gnu/bin/gcc-ld" "-fuse-ld=lld" "-Wl,--eh-frame-hdr" "-Wl,-z,noexecstack" "-L" "/opt/rustwide/rustup-home/toolchains/11663cd3bfefef7d34e8f0892c250bf698049392/lib/rustlib/x86_64-unknown-linux-gnu/lib" "-o" "/opt/rustwide/target/debug/deps/rust_os-2d21120333d9f0d5" "-Wl,--gc-sections" "-pie" "-Wl,-z,relro,-z,now" "-nodefaultlibs"
[INFO] [stdout]   = note: some arguments are omitted. use `--verbose` to show all linker arguments
[INFO] [stdout]   = note: rust-lld: error: duplicate symbol: _start
[INFO] [stdout]           >>> defined at /usr/lib/gcc/x86_64-linux-gnu/11/../../../x86_64-linux-gnu/Scrt1.o:(_start)
[INFO] [stdout]           >>> defined at main.rs:9 (src/main.rs:9)
[INFO] [stdout]           >>>            /opt/rustwide/target/debug/deps/rust_os-2d21120333d9f0d5.rust_os.7838d0709bb69d81-cgu.0.rcgu.o:(.text._start+0x0)
[INFO] [stdout]           collect2: error: ld returned 1 exit status
[INFO] [stdout]           
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rust_os` (bin "rust_os") due to 1 previous error; 3 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "0f1762ae0a2e38d5f3d4cbe97bb1d0d78e8f97f13517ae522b8879394f4da5b5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0f1762ae0a2e38d5f3d4cbe97bb1d0d78e8f97f13517ae522b8879394f4da5b5", kill_on_drop: false }`
[INFO] [stdout] 0f1762ae0a2e38d5f3d4cbe97bb1d0d78e8f97f13517ae522b8879394f4da5b5