[INFO] fetching crate json-trait-rs 0.11.0...
[INFO] testing json-trait-rs-0.11.0 against beta-2021-01-01 for beta-1.50-1
[INFO] extracting crate json-trait-rs 0.11.0 into /workspace/builds/worker-8/source
[INFO] validating manifest of crates.io crate json-trait-rs 0.11.0 on toolchain beta-2021-01-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate json-trait-rs 0.11.0
[INFO] finished tweaking crates.io crate json-trait-rs 0.11.0
[INFO] tweaked toml for crates.io crate json-trait-rs 0.11.0 written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "fetch" "--locked" "--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 pyo3-macros v0.13.0
[INFO] [stderr]   Downloaded test-case v1.0.0
[INFO] [stderr]   Downloaded pyo3 v0.13.0
[INFO] [stderr]   Downloaded pyo3-macros-backend v0.13.0
[INFO] [stderr]   Downloaded indoc v1.0.3
[INFO] [stderr]   Downloaded strum v0.20.0
[INFO] [stderr]   Downloaded join-lazy-fmt v0.9.2
[INFO] [stderr]   Downloaded strum_macros v0.20.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 9d60be1057ab004f41d184136d0d548f7fd23c294a29ba5ec3663a4da71d982a
[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" "9d60be1057ab004f41d184136d0d548f7fd23c294a29ba5ec3663a4da71d982a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9d60be1057ab004f41d184136d0d548f7fd23c294a29ba5ec3663a4da71d982a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9d60be1057ab004f41d184136d0d548f7fd23c294a29ba5ec3663a4da71d982a", kill_on_drop: false }`
[INFO] [stdout] 9d60be1057ab004f41d184136d0d548f7fd23c294a29ba5ec3663a4da71d982a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c672e6de2d5c9b8a2d5c4858c009ec9578ca7ee7cd1ab3c5d9ba06f343c20a29
[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" "c672e6de2d5c9b8a2d5c4858c009ec9578ca7ee7cd1ab3c5d9ba06f343c20a29", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.57
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling libc v0.2.81
[INFO] [stderr]    Compiling adler v0.2.3
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling gimli v0.23.0
[INFO] [stderr]    Compiling rustc-demangle v0.1.18
[INFO] [stderr]    Compiling cfg-if v1.0.0
[INFO] [stderr]    Compiling unicode-segmentation v1.7.1
[INFO] [stderr]    Compiling object v0.22.0
[INFO] [stderr]    Compiling join-lazy-fmt v0.9.2
[INFO] [stderr]    Compiling strum v0.20.0
[INFO] [stderr]    Compiling miniz_oxide v0.4.3
[INFO] [stderr]    Compiling heck v0.3.2
[INFO] [stderr]    Compiling addr2line v0.14.1
[INFO] [stderr]    Compiling backtrace v0.3.55
[INFO] [stderr]    Compiling synstructure v0.12.4
[INFO] [stderr]    Compiling strum_macros v0.20.1
[INFO] [stderr]    Compiling failure v0.1.8
[INFO] [stderr]    Compiling json-trait-rs v0.11.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]   --> src/lib.rs:43:1
[INFO] [stdout]    |
[INFO] [stdout] 43 | #![feature(specialization)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]   --> src/lib.rs:43:12
[INFO] [stdout]    |
[INFO] [stdout] 43 | #![feature(specialization)]
[INFO] [stdout]    |            ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]   --> src/lib.rs:37:5
[INFO] [stdout]    |
[INFO] [stdout] 37 |     warnings,
[INFO] [stdout]    |     ^^^^^^^^
[INFO] [stdout]    = note: `#[warn(incomplete_features)]` implied by `#[warn(warnings)]`
[INFO] [stdout]    = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout]    = help: consider using `min_specialization` instead, which is more stable and complete
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `json-trait-rs`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "c672e6de2d5c9b8a2d5c4858c009ec9578ca7ee7cd1ab3c5d9ba06f343c20a29", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c672e6de2d5c9b8a2d5c4858c009ec9578ca7ee7cd1ab3c5d9ba06f343c20a29", kill_on_drop: false }`
[INFO] [stdout] c672e6de2d5c9b8a2d5c4858c009ec9578ca7ee7cd1ab3c5d9ba06f343c20a29