[INFO] fetching crate alloc-cortex-m 0.4.0...
[INFO] checking alloc-cortex-m-0.4.0 against master#0d37dca25a51fb900a402c94c8818ad1c2789e30 for pr-77526
[INFO] extracting crate alloc-cortex-m 0.4.0 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate alloc-cortex-m 0.4.0 on toolchain 0d37dca25a51fb900a402c94c8818ad1c2789e30
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0d37dca25a51fb900a402c94c8818ad1c2789e30" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate alloc-cortex-m 0.4.0
[INFO] finished tweaking crates.io crate alloc-cortex-m 0.4.0
[INFO] tweaked toml for crates.io crate alloc-cortex-m 0.4.0 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate crates.io crate alloc-cortex-m 0.4.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0d37dca25a51fb900a402c94c8818ad1c2789e30" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+0d37dca25a51fb900a402c94c8818ad1c2789e30" "metadata" "--no-deps" "--format-version=1", 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] c427f7cf893f0f2be6f866a5bd0831e1af2eca06dd8b8c09d76e857a81d5e2a4
[INFO] running `Command { std: "docker" "start" "-a" "c427f7cf893f0f2be6f866a5bd0831e1af2eca06dd8b8c09d76e857a81d5e2a4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c427f7cf893f0f2be6f866a5bd0831e1af2eca06dd8b8c09d76e857a81d5e2a4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c427f7cf893f0f2be6f866a5bd0831e1af2eca06dd8b8c09d76e857a81d5e2a4", kill_on_drop: false }`
[INFO] [stdout] c427f7cf893f0f2be6f866a5bd0831e1af2eca06dd8b8c09d76e857a81d5e2a4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "-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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+0d37dca25a51fb900a402c94c8818ad1c2789e30" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4b6d45d3c4d55aefba90a6074b009f1a22dbedff975b79e4153e42993d8c911b
[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" "4b6d45d3c4d55aefba90a6074b009f1a22dbedff975b79e4153e42993d8c911b", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.12
[INFO] [stderr]     Checking stable_deref_trait v1.1.1
[INFO] [stderr]    Compiling syn v1.0.19
[INFO] [stderr]    Compiling cortex-m v0.6.2
[INFO] [stderr]     Checking vcell v0.1.2
[INFO] [stderr]    Compiling cortex-m-rt v0.6.12
[INFO] [stderr]     Checking linked_list_allocator v0.8.4
[INFO] [stderr]     Checking r0 v0.2.2
[INFO] [stderr]    Compiling bare-metal v0.2.5
[INFO] [stderr]     Checking as-slice v0.1.3
[INFO] [stderr]     Checking volatile-register v0.2.0
[INFO] [stdout] error[E0658]: mutable references are not allowed in constant functions
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/linked_list_allocator-0.8.4/src/hole.rs:18:23
[INFO] [stdout]    |
[INFO] [stdout] 18 |                 next: None,
[INFO] [stdout]    |                       ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #57349 <https://github.com/rust-lang/rust/issues/57349> for more information
[INFO] [stdout]    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0658`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `linked_list_allocator`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "4b6d45d3c4d55aefba90a6074b009f1a22dbedff975b79e4153e42993d8c911b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4b6d45d3c4d55aefba90a6074b009f1a22dbedff975b79e4153e42993d8c911b", kill_on_drop: false }`
[INFO] [stdout] 4b6d45d3c4d55aefba90a6074b009f1a22dbedff975b79e4153e42993d8c911b