[INFO] fetching crate alloc-cortex-m 0.4.0...
[INFO] checking alloc-cortex-m-0.4.0 against try#f47dd4da3ae8c32c9e65d307bfe640b143e674df for pr-77526
[INFO] extracting crate alloc-cortex-m 0.4.0 into /workspace/builds/worker-1/source
[INFO] validating manifest of crates.io crate alloc-cortex-m 0.4.0 on toolchain f47dd4da3ae8c32c9e65d307bfe640b143e674df
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+f47dd4da3ae8c32c9e65d307bfe640b143e674df" "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-1/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" "+f47dd4da3ae8c32c9e65d307bfe640b143e674df" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded linked_list_allocator v0.8.4
[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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+f47dd4da3ae8c32c9e65d307bfe640b143e674df" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 934519e2c3e313287086e75be143b8f161b5cda29219b54a0f2b0cbf4f3a8804
[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" "934519e2c3e313287086e75be143b8f161b5cda29219b54a0f2b0cbf4f3a8804", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "934519e2c3e313287086e75be143b8f161b5cda29219b54a0f2b0cbf4f3a8804", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "934519e2c3e313287086e75be143b8f161b5cda29219b54a0f2b0cbf4f3a8804", kill_on_drop: false }`
[INFO] [stdout] 934519e2c3e313287086e75be143b8f161b5cda29219b54a0f2b0cbf4f3a8804
[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=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" "+f47dd4da3ae8c32c9e65d307bfe640b143e674df" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f7fd1c4ce5c2727c887f0a60f2db9731436a2a3de9f8225163d33364fe2276d1
[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" "f7fd1c4ce5c2727c887f0a60f2db9731436a2a3de9f8225163d33364fe2276d1", kill_on_drop: false }`
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling proc-macro2 v1.0.12
[INFO] [stderr]    Compiling syn v1.0.19
[INFO] [stderr]     Checking stable_deref_trait v1.1.1
[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 r0 v0.2.2
[INFO] [stderr]     Checking linked_list_allocator v0.8.4
[INFO] [stderr]     Checking volatile-register v0.2.0
[INFO] [stderr]     Checking as-slice v0.1.3
[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" "f7fd1c4ce5c2727c887f0a60f2db9731436a2a3de9f8225163d33364fe2276d1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f7fd1c4ce5c2727c887f0a60f2db9731436a2a3de9f8225163d33364fe2276d1", kill_on_drop: false }`
[INFO] [stdout] f7fd1c4ce5c2727c887f0a60f2db9731436a2a3de9f8225163d33364fe2276d1