[INFO] updating cached repository https://github.com/lezwon/Blockchain-from-Scratch
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] a1e954e967cc24a8089a52d669fe970a2321feed
[INFO] checking lezwon/Blockchain-from-Scratch against master#2748a9fd93dd1a00a4521f4f16de5befbf77f6cd for pr-62262-1
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flezwon%2FBlockchain-from-Scratch" "/workspace/builds/worker-13/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-13/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/lezwon/Blockchain-from-Scratch on toolchain 2748a9fd93dd1a00a4521f4f16de5befbf77f6cd
[INFO] running `"/workspace/cargo-home/bin/cargo" "+2748a9fd93dd1a00a4521f4f16de5befbf77f6cd" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/lezwon/Blockchain-from-Scratch
[INFO] finished tweaking git repo https://github.com/lezwon/Blockchain-from-Scratch
[INFO] tweaked toml for git repo https://github.com/lezwon/Blockchain-from-Scratch written to /workspace/builds/worker-13/source/Cargo.toml
[INFO] crate git repo https://github.com/lezwon/Blockchain-from-Scratch already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+2748a9fd93dd1a00a4521f4f16de5befbf77f6cd" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-13/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+2748a9fd93dd1a00a4521f4f16de5befbf77f6cd" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] ccedb5f884389ed2ffad97b3867742b77448ce05f97e10b40d6471c1c8a15dd8
[INFO] running `"docker" "start" "-a" "ccedb5f884389ed2ffad97b3867742b77448ce05f97e10b40d6471c1c8a15dd8"`
[INFO] [stderr]     Checking serde v1.0.21
[INFO] [stderr]     Checking time v0.1.38
[INFO] [stderr]     Checking generic-array v0.9.0
[INFO] [stderr]    Compiling serde_derive v1.0.21
[INFO] [stderr]     Checking digest v0.7.2
[INFO] [stderr]     Checking sha2 v0.7.0
[INFO] [stderr]     Checking serde_json v1.0.6
[INFO] [stderr]     Checking blockchain-rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:94:8
[INFO] [stderr]    |
[INFO] [stderr] 94 |             let mut block_header = BlockHeader{
[INFO] [stderr]    |                 ----^^^^^^^^^^^^
[INFO] [stderr]    |                 |
[INFO] [stderr]    |                 help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:210:2
[INFO] [stderr]     |
[INFO] [stderr] 210 |     io::stdout().flush();
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:211:2
[INFO] [stderr]     |
[INFO] [stderr] 211 |     io::stdin().read_line(&mut miner_address);
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:213:2
[INFO] [stderr]     |
[INFO] [stderr] 213 |     io::stdout().flush();
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:214:2
[INFO] [stderr]     |
[INFO] [stderr] 214 |     io::stdin().read_line(&mut difficulty_string);
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:229:3
[INFO] [stderr]     |
[INFO] [stderr] 229 |         io::stdout().flush();
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:231:3
[INFO] [stderr]     |
[INFO] [stderr] 231 |         io::stdin().read_line(&mut choice);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:247:5
[INFO] [stderr]     |
[INFO] [stderr] 247 |                 io::stdout().flush();
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:248:5
[INFO] [stderr]     |
[INFO] [stderr] 248 |                 io::stdin().read_line(&mut sender);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:250:5
[INFO] [stderr]     |
[INFO] [stderr] 250 |                 io::stdout().flush();
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:251:5
[INFO] [stderr]     |
[INFO] [stderr] 251 |                 io::stdin().read_line(&mut recipient);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:253:5
[INFO] [stderr]     |
[INFO] [stderr] 253 |                 io::stdout().flush();
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:254:5
[INFO] [stderr]     |
[INFO] [stderr] 254 |                 io::stdin().read_line(&mut amount);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:274:5
[INFO] [stderr]     |
[INFO] [stderr] 274 |                 io::stdout().flush();
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:275:5
[INFO] [stderr]     |
[INFO] [stderr] 275 |                 io::stdin().read_line(&mut new_difficulty);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:286:5
[INFO] [stderr]     |
[INFO] [stderr] 286 |                 io::stdout().flush();
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:287:5
[INFO] [stderr]     |
[INFO] [stderr] 287 |                 io::stdin().read_line(&mut new_reward);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:94:8
[INFO] [stderr]    |
[INFO] [stderr] 94 |             let mut block_header = BlockHeader{
[INFO] [stderr]    |                 ----^^^^^^^^^^^^
[INFO] [stderr]    |                 |
[INFO] [stderr]    |                 help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:210:2
[INFO] [stderr]     |
[INFO] [stderr] 210 |     io::stdout().flush();
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:211:2
[INFO] [stderr]     |
[INFO] [stderr] 211 |     io::stdin().read_line(&mut miner_address);
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:213:2
[INFO] [stderr]     |
[INFO] [stderr] 213 |     io::stdout().flush();
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:214:2
[INFO] [stderr]     |
[INFO] [stderr] 214 |     io::stdin().read_line(&mut difficulty_string);
[INFO] [stderr]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:229:3
[INFO] [stderr]     |
[INFO] [stderr] 229 |         io::stdout().flush();
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:231:3
[INFO] [stderr]     |
[INFO] [stderr] 231 |         io::stdin().read_line(&mut choice);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:247:5
[INFO] [stderr]     |
[INFO] [stderr] 247 |                 io::stdout().flush();
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:248:5
[INFO] [stderr]     |
[INFO] [stderr] 248 |                 io::stdin().read_line(&mut sender);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:250:5
[INFO] [stderr]     |
[INFO] [stderr] 250 |                 io::stdout().flush();
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:251:5
[INFO] [stderr]     |
[INFO] [stderr] 251 |                 io::stdin().read_line(&mut recipient);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:253:5
[INFO] [stderr]     |
[INFO] [stderr] 253 |                 io::stdout().flush();
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:254:5
[INFO] [stderr]     |
[INFO] [stderr] 254 |                 io::stdin().read_line(&mut amount);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:274:5
[INFO] [stderr]     |
[INFO] [stderr] 274 |                 io::stdout().flush();
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:275:5
[INFO] [stderr]     |
[INFO] [stderr] 275 |                 io::stdin().read_line(&mut new_difficulty);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:286:5
[INFO] [stderr]     |
[INFO] [stderr] 286 |                 io::stdout().flush();
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr] warning: unused `std::result::Result` that must be used
[INFO] [stderr]    --> src/main.rs:287:5
[INFO] [stderr]     |
[INFO] [stderr] 287 |                 io::stdin().read_line(&mut new_reward);
[INFO] [stderr]     |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 16.12s
[INFO] running `"docker" "inspect" "ccedb5f884389ed2ffad97b3867742b77448ce05f97e10b40d6471c1c8a15dd8"`
[INFO] running `"docker" "rm" "-f" "ccedb5f884389ed2ffad97b3867742b77448ce05f97e10b40d6471c1c8a15dd8"`
[INFO] [stdout] ccedb5f884389ed2ffad97b3867742b77448ce05f97e10b40d6471c1c8a15dd8