Dec 11 16:25:33.899 INFO checking jfredett/synacor against master#3a75e80557a103497cffbcab395a2f37061a77ea for pr-56677
Dec 11 16:25:33.899 INFO running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/pr-56677/worker-4/master#3a75e80557a103497cffbcab395a2f37061a77ea:/target:rw,Z" "-v" "/mnt/big/crater/work/local/test-source/worker-4/pr-56677/master#3a75e80557a103497cffbcab395a2f37061a77ea:/source:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/source" "-e" "USER_ID=1000" "-e" "CMD=cargo +3a75e80557a103497cffbcab395a2f37061a77ea-alt check --frozen --all --all-targets" "-e" "CARGO_TARGET_DIR=/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/cargo-home" "-e" "RUSTUP_HOME=/rustup-home" "-m" "1536M" "--network" "none" "crater"`
Dec 11 16:25:34.356 INFO [stdout] f4550b96883ff2a3918bd68e85655ceeebc498d1c58454ebbcd0b9f87d5fb166
Dec 11 16:25:34.364 INFO running `"docker" "start" "-a" "f4550b96883ff2a3918bd68e85655ceeebc498d1c58454ebbcd0b9f87d5fb166"`
Dec 11 16:25:35.793 INFO [stderr] usermod: no changes
Dec 11 16:25:35.929 INFO [stderr]     Checking synacor v0.1.0 (/source)
Dec 11 16:25:37.092 INFO [stderr] warning: unused `std::result::Result` that must be used
Dec 11 16:25:37.092 INFO [stderr]    --> src/vm.rs:186:9
Dec 11 16:25:37.092 INFO [stderr]     |
Dec 11 16:25:37.092 INFO [stderr] 186 |         stdin.read_exact(&mut buf);
Dec 11 16:25:37.093 INFO [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 11 16:25:37.093 INFO [stderr]     |
Dec 11 16:25:37.093 INFO [stderr]     = note: #[warn(unused_must_use)] on by default
Dec 11 16:25:37.093 INFO [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
Dec 11 16:25:37.093 INFO [stderr] 
Dec 11 16:25:40.501 INFO [stderr] warning: unused arithmetic operation that must be used
Dec 11 16:25:40.501 INFO [stderr]    --> src/u15.rs:163:30
Dec 11 16:25:40.501 INFO [stderr]     |
Dec 11 16:25:40.501 INFO [stderr] 163 |         fn sub_underflow() { u15(0) - u15(2); }
Dec 11 16:25:40.502 INFO [stderr]     |                              ^^^^^^^^^^^^^^^
Dec 11 16:25:40.502 INFO [stderr]     |
Dec 11 16:25:40.502 INFO [stderr]     = note: #[warn(unused_must_use)] on by default
Dec 11 16:25:40.502 INFO [stderr] 
Dec 11 16:25:40.502 INFO [stderr] warning: unused arithmetic operation that must be used
Dec 11 16:25:40.502 INFO [stderr]    --> src/u15.rs:167:28
Dec 11 16:25:40.502 INFO [stderr]     |
Dec 11 16:25:40.502 INFO [stderr] 167 |         fn div_by_zero() { u15(1) / u15(0); }
Dec 11 16:25:40.502 INFO [stderr]     |                            ^^^^^^^^^^^^^^^
Dec 11 16:25:40.502 INFO [stderr] 
Dec 11 16:25:40.504 INFO [stderr] warning: unused arithmetic operation that must be used
Dec 11 16:25:40.504 INFO [stderr]    --> src/u15.rs:223:26
Dec 11 16:25:40.504 INFO [stderr]     |
Dec 11 16:25:40.504 INFO [stderr] 223 |         fn sub_panic() { u15(16) - u15(17); }
Dec 11 16:25:40.504 INFO [stderr]     |                          ^^^^^^^^^^^^^^^^^
Dec 11 16:25:40.504 INFO [stderr] 
Dec 11 16:25:40.550 INFO [stderr] warning: unused `std::result::Result` that must be used
Dec 11 16:25:40.550 INFO [stderr]    --> src/vm.rs:186:9
Dec 11 16:25:40.550 INFO [stderr]     |
Dec 11 16:25:40.550 INFO [stderr] 186 |         stdin.read_exact(&mut buf);
Dec 11 16:25:40.550 INFO [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dec 11 16:25:40.550 INFO [stderr]     |
Dec 11 16:25:40.550 INFO [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
Dec 11 16:25:40.550 INFO [stderr] 
Dec 11 16:25:40.632 INFO [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 4.81s
Dec 11 16:25:40.640 INFO [stderr] su: No module specific data is present
Dec 11 16:25:41.012 INFO running `"docker" "inspect" "f4550b96883ff2a3918bd68e85655ceeebc498d1c58454ebbcd0b9f87d5fb166"`
Dec 11 16:25:41.157 INFO running `"docker" "rm" "-f" "f4550b96883ff2a3918bd68e85655ceeebc498d1c58454ebbcd0b9f87d5fb166"`
Dec 11 16:25:41.363 INFO [stdout] f4550b96883ff2a3918bd68e85655ceeebc498d1c58454ebbcd0b9f87d5fb166