[INFO] cloning repository https://github.com/Rudo2204/tivac-rtic
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Rudo2204/tivac-rtic" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FRudo2204%2Ftivac-rtic", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FRudo2204%2Ftivac-rtic'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] edcefe719aaa3b5abcc3bb58b20ce0d80f331d8b
[INFO] testing Rudo2204/tivac-rtic against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FRudo2204%2Ftivac-rtic" "/workspace/builds/worker-1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Rudo2204/tivac-rtic on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-1/source/.cargo/config
[INFO] started tweaking git repo https://github.com/Rudo2204/tivac-rtic
[INFO] finished tweaking git repo https://github.com/Rudo2204/tivac-rtic
[INFO] tweaked toml for git repo https://github.com/Rudo2204/tivac-rtic written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/Rudo2204/tivac-rtic already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "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] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded cast v0.2.5
[INFO] [stderr]   Downloaded bare-metal v0.2.5
[INFO] [stderr]   Downloaded cortex-m-semihosting v0.3.7
[INFO] [stderr]   Downloaded cortex-m-rtic v0.5.6
[INFO] [stderr]   Downloaded alloc-cortex-m v0.4.1
[INFO] [stderr]   Downloaded rtic-syntax v0.4.0
[INFO] [stderr]   Downloaded cortex-m-rtic-macros v0.5.2
[INFO] [stderr]   Downloaded nb v0.1.3
[INFO] [stderr]   Downloaded embedded-hal v0.2.4
[INFO] [stderr]   Downloaded bitfield v0.13.2
[INFO] [stderr]   Downloaded aligned v0.3.4
[INFO] [stderr]   Downloaded rtic-core v0.3.1
[INFO] [stderr]   Downloaded cortex-m v0.7.2
[INFO] [stderr]   Downloaded hd44780-driver v0.4.0
[INFO] [stderr]   Downloaded nb v1.0.0
[INFO] [stderr]   Downloaded volatile-register v0.2.0
[INFO] [stderr]   Downloaded cortex-m-rt v0.6.13
[INFO] [stderr]   Downloaded vcell v0.1.3
[INFO] [stderr]   Downloaded r0 v0.2.2
[INFO] [stderr]   Downloaded generic-array v0.11.2
[INFO] [stderr]   Downloaded cortex-m v0.6.7
[INFO] [stderr]   Downloaded cortex-m-rt-macros v0.1.8
[INFO] [stderr]   Downloaded mfrc522 v0.2.0
[INFO] [stderr]   Downloaded numtoa v0.2.3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 33f47d7d6be42bfc8e351886f0dee29b8dae6e9156bcf6a69b2155acb712fb53
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "33f47d7d6be42bfc8e351886f0dee29b8dae6e9156bcf6a69b2155acb712fb53", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "33f47d7d6be42bfc8e351886f0dee29b8dae6e9156bcf6a69b2155acb712fb53", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "33f47d7d6be42bfc8e351886f0dee29b8dae6e9156bcf6a69b2155acb712fb53", kill_on_drop: false }`
[INFO] [stdout] 33f47d7d6be42bfc8e351886f0dee29b8dae6e9156bcf6a69b2155acb712fb53
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 770d4a23e8d25f1542a2ceaeb8a6b44bde93bc16d6d743e13c437b736b25cb3a
[INFO] running `Command { std: "docker" "start" "-a" "770d4a23e8d25f1542a2ceaeb8a6b44bde93bc16d6d743e13c437b736b25cb3a", kill_on_drop: false }`
[INFO] [stderr]    Compiling cortex-m v0.7.2
[INFO] [stderr]    Compiling nb v1.0.0
[INFO] [stderr]    Compiling proc-macro2 v1.0.26
[INFO] [stderr]    Compiling void v1.0.2
[INFO] [stderr]    Compiling syn v1.0.70
[INFO] [stderr]    Compiling stable_deref_trait v1.2.0
[INFO] [stderr]    Compiling vcell v0.1.3
[INFO] [stderr]    Compiling bitfield v0.13.2
[INFO] [stderr]    Compiling cortex-m v0.6.7
[INFO] [stderr]    Compiling cortex-m-rt v0.6.13
[INFO] [stderr]    Compiling r0 v0.2.2
[INFO] [stderr]    Compiling heapless v0.6.1
[INFO] [stderr]    Compiling tm4c123x v0.9.0 (https://github.com/rust-embedded-community/tm4c-rs.git#30145706)
[INFO] [stderr]    Compiling byteorder v1.4.3
[INFO] [stderr]    Compiling tm4c123x-hal v0.10.2 (https://github.com/Rudo2204/tm4c-rs.git?rev=9a9580d#9a9580db)
[INFO] [stderr]    Compiling cortex-m-semihosting v0.3.7
[INFO] [stderr]    Compiling tivac-rtic v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]    Compiling linked_list_allocator v0.8.11
[INFO] [stderr]    Compiling rtic-core v0.3.1
[INFO] [stderr]    Compiling panic-halt v0.2.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/linked_list_allocator-0.8.11/src/lib.rs:1:41
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![cfg_attr(feature = "const_mut_refs", feature(const_mut_refs))]
[INFO] [stdout]   |                                         ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling numtoa v0.2.3
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `linked_list_allocator` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "770d4a23e8d25f1542a2ceaeb8a6b44bde93bc16d6d743e13c437b736b25cb3a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "770d4a23e8d25f1542a2ceaeb8a6b44bde93bc16d6d743e13c437b736b25cb3a", kill_on_drop: false }`
[INFO] [stdout] 770d4a23e8d25f1542a2ceaeb8a6b44bde93bc16d6d743e13c437b736b25cb3a