[INFO] cloning repository https://github.com/Snektron/mamba
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Snektron/mamba" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FSnektron%2Fmamba", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FSnektron%2Fmamba'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 8e16034b3ed9bcf9a5a92b15d9ce65d3bcf8360e
[INFO] checking Snektron/mamba against try#d990716b6a1fdde1300748828a9c9e79dfd0b898 for pr-74846
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FSnektron%2Fmamba" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Snektron/mamba on toolchain d990716b6a1fdde1300748828a9c9e79dfd0b898
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+d990716b6a1fdde1300748828a9c9e79dfd0b898" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Snektron/mamba
[INFO] finished tweaking git repo https://github.com/Snektron/mamba
[INFO] tweaked toml for git repo https://github.com/Snektron/mamba written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+d990716b6a1fdde1300748828a9c9e79dfd0b898" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+d990716b6a1fdde1300748828a9c9e79dfd0b898" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+d990716b6a1fdde1300748828a9c9e79dfd0b898" "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] 9b915d14ead3c3e6bb1739a0d3a4e6398eeb7835777349388e443a0877ae8f9c
[INFO] running `Command { std: "docker" "start" "-a" "9b915d14ead3c3e6bb1739a0d3a4e6398eeb7835777349388e443a0877ae8f9c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9b915d14ead3c3e6bb1739a0d3a4e6398eeb7835777349388e443a0877ae8f9c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9b915d14ead3c3e6bb1739a0d3a4e6398eeb7835777349388e443a0877ae8f9c", kill_on_drop: false }`
[INFO] [stdout] 9b915d14ead3c3e6bb1739a0d3a4e6398eeb7835777349388e443a0877ae8f9c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+d990716b6a1fdde1300748828a9c9e79dfd0b898" "check" "--frozen" "--all" "--all-targets" "--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] 0bf9d01fdb49fb02d04cc1f8fc959c6b06bf4cf9c46e5a0e1fcca43f997155b4
[INFO] running `Command { std: "docker" "start" "-a" "0bf9d01fdb49fb02d04cc1f8fc959c6b06bf4cf9c46e5a0e1fcca43f997155b4", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.74
[INFO] [stderr]    Compiling proc-macro2 v1.0.19
[INFO] [stderr]    Compiling syn v1.0.38
[INFO] [stderr]    Compiling byteorder v1.3.4
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling lalrpop-util v0.16.3
[INFO] [stderr]     Checking unicode-width v0.1.8
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]     Checking ansi_term v0.11.0
[INFO] [stderr]     Checking strsim v0.8.0
[INFO] [stderr]     Checking vec_map v0.8.2
[INFO] [stderr]    Compiling thread_local v1.0.1
[INFO] [stderr]    Compiling ascii-canvas v1.0.0
[INFO] [stderr]    Compiling aho-corasick v0.7.13
[INFO] [stderr]    Compiling ena v0.11.0
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]    Compiling block-buffer v0.7.3
[INFO] [stderr]    Compiling sha2 v0.8.2
[INFO] [stderr]     Checking regex v1.3.9
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]     Checking clap v2.33.3
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling phf_generator v0.7.24
[INFO] [stderr]    Compiling string_cache_codegen v0.4.4
[INFO] [stderr]    Compiling string_cache v0.7.5
[INFO] [stderr]    Compiling serde_derive v1.0.115
[INFO] [stderr]    Compiling serde v1.0.115
[INFO] [stderr]    Compiling docopt v1.1.0
[INFO] [stderr]    Compiling lalrpop v0.16.3
[INFO] [stderr]    Compiling mamba v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:1861:5
[INFO] [stdout]      |
[INFO] [stdout] 1861 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout]      = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:1934:5
[INFO] [stdout]      |
[INFO] [stdout] 1934 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:1947:5
[INFO] [stdout]      |
[INFO] [stdout] 1947 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:1995:5
[INFO] [stdout]      |
[INFO] [stdout] 1995 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:2009:5
[INFO] [stdout]      |
[INFO] [stdout] 2009 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:2216:5
[INFO] [stdout]      |
[INFO] [stdout] 2216 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:1861:5
[INFO] [stdout]      |
[INFO] [stdout] 1861 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout]      |
[INFO] [stdout]      = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:1934:5
[INFO] [stdout]      |
[INFO] [stdout] 1934 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:1947:5
[INFO] [stdout]      |
[INFO] [stdout] 1947 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:1995:5
[INFO] [stdout]      |
[INFO] [stdout] 1995 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:2009:5
[INFO] [stdout]      |
[INFO] [stdout] 2009 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]     --> /opt/rustwide/target/debug/build/mamba-b302f74787c61c28/out/parser/grammar.rs:2216:5
[INFO] [stdout]      |
[INFO] [stdout] 2216 |     (__0)
[INFO] [stdout]      |     ^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/ast/construct.rs:188:13
[INFO] [stdout]     |
[INFO] [stdout] 188 |         let mut t = check_arms(&from, arms, &states, &alphabet)?;
[INFO] [stdout]     |             ----^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/ast/construct.rs:188:13
[INFO] [stdout]     |
[INFO] [stdout] 188 |         let mut t = check_arms(&from, arms, &states, &alphabet)?;
[INFO] [stdout]     |             ----^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1m 01s
[INFO] running `Command { std: "docker" "inspect" "0bf9d01fdb49fb02d04cc1f8fc959c6b06bf4cf9c46e5a0e1fcca43f997155b4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0bf9d01fdb49fb02d04cc1f8fc959c6b06bf4cf9c46e5a0e1fcca43f997155b4", kill_on_drop: false }`
[INFO] [stdout] 0bf9d01fdb49fb02d04cc1f8fc959c6b06bf4cf9c46e5a0e1fcca43f997155b4