[INFO] cloning repository https://github.com/noormohammedb/rust-tcp-implementation
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/noormohammedb/rust-tcp-implementation" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnoormohammedb%2Frust-tcp-implementation", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnoormohammedb%2Frust-tcp-implementation'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 3f31a26c074cd0c0a9dd06f830c68d06701d89c6
[INFO] checking noormohammedb/rust-tcp-implementation against master#8a65ee08296b36342bf7c3cdc15312ccbc357227 for pr-142704
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fnoormohammedb%2Frust-tcp-implementation" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/noormohammedb/rust-tcp-implementation on toolchain 8a65ee08296b36342bf7c3cdc15312ccbc357227
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+8a65ee08296b36342bf7c3cdc15312ccbc357227" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/noormohammedb/rust-tcp-implementation
[INFO] finished tweaking git repo https://github.com/noormohammedb/rust-tcp-implementation
[INFO] tweaked toml for git repo https://github.com/noormohammedb/rust-tcp-implementation written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/noormohammedb/rust-tcp-implementation already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+8a65ee08296b36342bf7c3cdc15312ccbc357227" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+8a65ee08296b36342bf7c3cdc15312ccbc357227" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 95796575df51b13018f56836f3c8b027333c8e9a0d167bb5b6213932fa1a7095
[INFO] running `Command { std: "docker" "start" "-a" "95796575df51b13018f56836f3c8b027333c8e9a0d167bb5b6213932fa1a7095", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "95796575df51b13018f56836f3c8b027333c8e9a0d167bb5b6213932fa1a7095", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "95796575df51b13018f56836f3c8b027333c8e9a0d167bb5b6213932fa1a7095", kill_on_drop: false }`
[INFO] [stdout] 95796575df51b13018f56836f3c8b027333c8e9a0d167bb5b6213932fa1a7095
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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" "RUSTDOCFLAGS=--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:90999bfc7ae267e83380e433d8e61a7c072ca6729e92edbae886d3423b3a6f4c" "/opt/rustwide/cargo-home/bin/cargo" "+8a65ee08296b36342bf7c3cdc15312ccbc357227" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 0b3dd3a96ef9863f044ad1c71593604ec936ba93801cbb8a915925055781e616
[INFO] running `Command { std: "docker" "start" "-a" "0b3dd3a96ef9863f044ad1c71593604ec936ba93801cbb8a915925055781e616", kill_on_drop: false }`
[INFO] [stderr]    Compiling autocfg v1.1.0
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]    Compiling libc v0.2.146
[INFO] [stderr]    Compiling maybe-uninit v2.0.0
[INFO] [stderr]     Checking lazy_static v1.4.0
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]     Checking futures v0.1.31
[INFO] [stderr]     Checking scopeguard v1.1.0
[INFO] [stderr]     Checking log v0.4.20
[INFO] [stderr]     Checking byteorder v1.4.3
[INFO] [stderr]     Checking fnv v1.0.7
[INFO] [stderr]    Compiling cc v1.0.79
[INFO] [stderr]     Checking scoped-tls v0.1.2
[INFO] [stderr]     Checking arrayvec v0.7.4
[INFO] [stderr]     Checking lock_api v0.3.4
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling crossbeam-utils v0.7.2
[INFO] [stderr]    Compiling slab v0.4.8
[INFO] [stderr]    Compiling memoffset v0.5.6
[INFO] [stderr]    Compiling crossbeam-epoch v0.8.2
[INFO] [stderr]     Checking etherparse v0.13.0
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]     Checking smallvec v0.6.14
[INFO] [stderr]    Compiling parking_lot_core v0.6.3
[INFO] [stderr]    Compiling parking_lot v0.9.0
[INFO] [stderr]    Compiling tun-tap v0.1.3
[INFO] [stderr]     Checking crossbeam-queue v0.2.3
[INFO] [stderr]     Checking iovec v0.1.4
[INFO] [stderr]     Checking net2 v0.2.39
[INFO] [stderr]     Checking num_cpus v1.15.0
[INFO] [stderr]     Checking crossbeam-deque v0.7.4
[INFO] [stderr]     Checking tokio-executor v0.1.10
[INFO] [stderr]     Checking tokio-sync v0.1.8
[INFO] [stderr]     Checking bytes v0.4.12
[INFO] [stderr]     Checking tokio-timer v0.2.13
[INFO] [stderr]     Checking tokio-current-thread v0.1.7
[INFO] [stderr]     Checking tokio-threadpool v0.1.18
[INFO] [stderr]     Checking mio v0.6.23
[INFO] [stderr]     Checking tokio-io v0.1.13
[INFO] [stderr]     Checking tokio-codec v0.1.2
[INFO] [stderr]     Checking tokio-fs v0.1.7
[INFO] [stderr]     Checking tokio-reactor v0.1.12
[INFO] [stderr]     Checking mio-uds v0.6.8
[INFO] [stderr]     Checking tokio-uds v0.2.7
[INFO] [stderr]     Checking tokio-tcp v0.1.4
[INFO] [stderr]     Checking tokio-udp v0.1.6
[INFO] [stderr]     Checking tokio v0.1.22
[INFO] [stderr]     Checking tokio-core v0.1.18
[INFO] [stderr]     Checking trust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> src/main.rs:87:5
[INFO] [stdout]    |
[INFO] [stdout] 21 | /     loop {
[INFO] [stdout] 22 | |         let nbytes = nic.recv(&mut buf[..])?;
[INFO] [stdout] ...  |
[INFO] [stdout] 86 | |     }
[INFO] [stdout]    | |_____- any code following this expression is unreachable
[INFO] [stdout] 87 |       Ok(())
[INFO] [stdout]    |       ^^^^^^ unreachable expression
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `unwritten`
[INFO] [stdout]    --> src/tcp_state.rs:158:13
[INFO] [stdout]     |
[INFO] [stdout] 158 |         let unwritten = {
[INFO] [stdout]     |             ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_unwritten`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/tcp_state.rs:115:13
[INFO] [stdout]     |
[INFO] [stdout] 115 |         let mut c = Connection {
[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/tcp_state.rs:147:13
[INFO] [stdout]     |
[INFO] [stdout] 147 |         let mut syn_ack_ip_packet = Ipv4Header::new(
[INFO] [stdout]     |             ----^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `nic`
[INFO] [stdout]    --> src/tcp_state.rs:177:9
[INFO] [stdout]     |
[INFO] [stdout] 177 |         nic: &mut tun_tap::Iface,
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_nic`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `iph`
[INFO] [stdout]    --> src/tcp_state.rs:178:9
[INFO] [stdout]     |
[INFO] [stdout] 178 |         iph: Ipv4HeaderSlice,
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_iph`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `tcph`
[INFO] [stdout]    --> src/tcp_state.rs:179:9
[INFO] [stdout]     |
[INFO] [stdout] 179 |         tcph: TcpHeaderSlice,
[INFO] [stdout]     |         ^^^^ help: if this is intentional, prefix it with an underscore: `_tcph`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `data`
[INFO] [stdout]    --> src/tcp_state.rs:180:9
[INFO] [stdout]     |
[INFO] [stdout] 180 |         data: &[u8],
[INFO] [stdout]     |         ^^^^ help: if this is intentional, prefix it with an underscore: `_data`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ip_hr_sz`
[INFO] [stdout]   --> src/main.rs:32:13
[INFO] [stdout]    |
[INFO] [stdout] 32 |         let ip_hr_sz = 20; // min ip header size
[INFO] [stdout]    |             ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_ip_hr_sz`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `packet_version`
[INFO] [stdout]   --> src/main.rs:38:21
[INFO] [stdout]    |
[INFO] [stdout] 38 |                 let packet_version = iph.version();
[INFO] [stdout]    |                     ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_packet_version`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t_len`
[INFO] [stdout]   --> src/main.rs:42:21
[INFO] [stdout]    |
[INFO] [stdout] 42 |                 let t_len = iph.total_len();
[INFO] [stdout]    |                     ^^^^^ help: if this is intentional, prefix it with an underscore: `_t_len`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `p_len`
[INFO] [stdout]   --> src/main.rs:43:21
[INFO] [stdout]    |
[INFO] [stdout] 43 |                 let p_len = iph.payload_len();
[INFO] [stdout]    |                     ^^^^^ help: if this is intentional, prefix it with an underscore: `_p_len`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:69:43
[INFO] [stdout]    |
[INFO] [stdout] 69 | ...                   Entry::Vacant(mut e) => {
[INFO] [stdout]    |                                     ----^
[INFO] [stdout]    |                                     |
[INFO] [stdout]    |                                     help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `ETHERTYPE_IPV4` is never used
[INFO] [stdout]  --> src/main.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 | const ETHERTYPE_IPV4: u16 = 0x0800;
[INFO] [stdout]   |       ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `state` and `recv` are never read
[INFO] [stdout]   --> src/tcp_state.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 17 | pub struct Connection {
[INFO] [stdout]    |            ---------- fields in this struct
[INFO] [stdout] 18 |     state: State,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 19 |     send: SendSequenceSpace,
[INFO] [stdout] 20 |     recv: ReceiveSequenceSpace,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `Connection` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> src/main.rs:87:5
[INFO] [stdout]    |
[INFO] [stdout] 21 | /     loop {
[INFO] [stdout] 22 | |         let nbytes = nic.recv(&mut buf[..])?;
[INFO] [stdout] ...  |
[INFO] [stdout] 86 | |     }
[INFO] [stdout]    | |_____- any code following this expression is unreachable
[INFO] [stdout] 87 |       Ok(())
[INFO] [stdout]    |       ^^^^^^ unreachable expression
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `una`, `nxt`, `up`, `wl1`, and `wl2` are never read
[INFO] [stdout]   --> src/tcp_state.rs:39:5
[INFO] [stdout]    |
[INFO] [stdout] 37 | struct SendSequenceSpace {
[INFO] [stdout]    |        ----------------- fields in this struct
[INFO] [stdout] 38 |     /// send unacknowledged
[INFO] [stdout] 39 |     una: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 40 |     /// send next
[INFO] [stdout] 41 |     nxt: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] ...
[INFO] [stdout] 45 |     up: bool,
[INFO] [stdout]    |     ^^
[INFO] [stdout] 46 |     /// segment sequence number used for last window update
[INFO] [stdout] 47 |     wl1: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 48 |     /// segment acknowledgment number used for last window update
[INFO] [stdout] 49 |     wl2: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `SendSequenceSpace` has derived impls for the traits `Default` and `Debug`, but these are intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `nxt`, `wnd`, `up`, and `irs` are never read
[INFO] [stdout]   --> src/tcp_state.rs:69:5
[INFO] [stdout]    |
[INFO] [stdout] 67 | struct ReceiveSequenceSpace {
[INFO] [stdout]    |        -------------------- fields in this struct
[INFO] [stdout] 68 |     /// RCV.NXT - receive next
[INFO] [stdout] 69 |     nxt: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 70 |     /// RCV.WND - receive window
[INFO] [stdout] 71 |     wnd: u16,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 72 |     /// RCV.UP  - receive urgent pointer
[INFO] [stdout] 73 |     up: bool,
[INFO] [stdout]    |     ^^
[INFO] [stdout] 74 |     /// IRS     - initial receive sequence number
[INFO] [stdout] 75 |     irs: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `ReceiveSequenceSpace` has derived impls for the traits `Default` and `Debug`, but these are intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/tcp_state.rs:171:9
[INFO] [stdout]     |
[INFO] [stdout] 171 |         nic.send(&buf[..syn_ack_ip_packet.header_len() + syn_ack.header_len() as usize + ip_hr_of]);
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 171 |         let _ = nic.send(&buf[..syn_ack_ip_packet.header_len() + syn_ack.header_len() as usize + ip_hr_of]);
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `unwritten`
[INFO] [stdout]    --> src/tcp_state.rs:158:13
[INFO] [stdout]     |
[INFO] [stdout] 158 |         let unwritten = {
[INFO] [stdout]     |             ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_unwritten`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/tcp_state.rs:115:13
[INFO] [stdout]     |
[INFO] [stdout] 115 |         let mut c = Connection {
[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/tcp_state.rs:147:13
[INFO] [stdout]     |
[INFO] [stdout] 147 |         let mut syn_ack_ip_packet = Ipv4Header::new(
[INFO] [stdout]     |             ----^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |             |
[INFO] [stdout]     |             help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `nic`
[INFO] [stdout]    --> src/tcp_state.rs:177:9
[INFO] [stdout]     |
[INFO] [stdout] 177 |         nic: &mut tun_tap::Iface,
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_nic`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `iph`
[INFO] [stdout]    --> src/tcp_state.rs:178:9
[INFO] [stdout]     |
[INFO] [stdout] 178 |         iph: Ipv4HeaderSlice,
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_iph`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `tcph`
[INFO] [stdout]    --> src/tcp_state.rs:179:9
[INFO] [stdout]     |
[INFO] [stdout] 179 |         tcph: TcpHeaderSlice,
[INFO] [stdout]     |         ^^^^ help: if this is intentional, prefix it with an underscore: `_tcph`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `data`
[INFO] [stdout]    --> src/tcp_state.rs:180:9
[INFO] [stdout]     |
[INFO] [stdout] 180 |         data: &[u8],
[INFO] [stdout]     |         ^^^^ help: if this is intentional, prefix it with an underscore: `_data`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `ip_hr_sz`
[INFO] [stdout]   --> src/main.rs:32:13
[INFO] [stdout]    |
[INFO] [stdout] 32 |         let ip_hr_sz = 20; // min ip header size
[INFO] [stdout]    |             ^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_ip_hr_sz`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `packet_version`
[INFO] [stdout]   --> src/main.rs:38:21
[INFO] [stdout]    |
[INFO] [stdout] 38 |                 let packet_version = iph.version();
[INFO] [stdout]    |                     ^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_packet_version`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `t_len`
[INFO] [stdout]   --> src/main.rs:42:21
[INFO] [stdout]    |
[INFO] [stdout] 42 |                 let t_len = iph.total_len();
[INFO] [stdout]    |                     ^^^^^ help: if this is intentional, prefix it with an underscore: `_t_len`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `p_len`
[INFO] [stdout]   --> src/main.rs:43:21
[INFO] [stdout]    |
[INFO] [stdout] 43 |                 let p_len = iph.payload_len();
[INFO] [stdout]    |                     ^^^^^ help: if this is intentional, prefix it with an underscore: `_p_len`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:69:43
[INFO] [stdout]    |
[INFO] [stdout] 69 | ...                   Entry::Vacant(mut e) => {
[INFO] [stdout]    |                                     ----^
[INFO] [stdout]    |                                     |
[INFO] [stdout]    |                                     help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: constant `ETHERTYPE_IPV4` is never used
[INFO] [stdout]  --> src/main.rs:4:7
[INFO] [stdout]   |
[INFO] [stdout] 4 | const ETHERTYPE_IPV4: u16 = 0x0800;
[INFO] [stdout]   |       ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `state` and `recv` are never read
[INFO] [stdout]   --> src/tcp_state.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 17 | pub struct Connection {
[INFO] [stdout]    |            ---------- fields in this struct
[INFO] [stdout] 18 |     state: State,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 19 |     send: SendSequenceSpace,
[INFO] [stdout] 20 |     recv: ReceiveSequenceSpace,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `Connection` has a derived impl for the trait `Debug`, but this is intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `una`, `nxt`, `up`, `wl1`, and `wl2` are never read
[INFO] [stdout]   --> src/tcp_state.rs:39:5
[INFO] [stdout]    |
[INFO] [stdout] 37 | struct SendSequenceSpace {
[INFO] [stdout]    |        ----------------- fields in this struct
[INFO] [stdout] 38 |     /// send unacknowledged
[INFO] [stdout] 39 |     una: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 40 |     /// send next
[INFO] [stdout] 41 |     nxt: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] ...
[INFO] [stdout] 45 |     up: bool,
[INFO] [stdout]    |     ^^
[INFO] [stdout] 46 |     /// segment sequence number used for last window update
[INFO] [stdout] 47 |     wl1: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 48 |     /// segment acknowledgment number used for last window update
[INFO] [stdout] 49 |     wl2: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `SendSequenceSpace` has derived impls for the traits `Default` and `Debug`, but these are intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `nxt`, `wnd`, `up`, and `irs` are never read
[INFO] [stdout]   --> src/tcp_state.rs:69:5
[INFO] [stdout]    |
[INFO] [stdout] 67 | struct ReceiveSequenceSpace {
[INFO] [stdout]    |        -------------------- fields in this struct
[INFO] [stdout] 68 |     /// RCV.NXT - receive next
[INFO] [stdout] 69 |     nxt: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 70 |     /// RCV.WND - receive window
[INFO] [stdout] 71 |     wnd: u16,
[INFO] [stdout]    |     ^^^
[INFO] [stdout] 72 |     /// RCV.UP  - receive urgent pointer
[INFO] [stdout] 73 |     up: bool,
[INFO] [stdout]    |     ^^
[INFO] [stdout] 74 |     /// IRS     - initial receive sequence number
[INFO] [stdout] 75 |     irs: u32,
[INFO] [stdout]    |     ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `ReceiveSequenceSpace` has derived impls for the traits `Default` and `Debug`, but these are intentionally ignored during dead code analysis
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/tcp_state.rs:171:9
[INFO] [stdout]     |
[INFO] [stdout] 171 |         nic.send(&buf[..syn_ack_ip_packet.header_len() + syn_ack.header_len() as usize + ip_hr_of]);
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 171 |         let _ = nic.send(&buf[..syn_ack_ip_packet.header_len() + syn_ack.header_len() as usize + ip_hr_of]);
[INFO] [stdout]     |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 3.51s
[INFO] running `Command { std: "docker" "inspect" "0b3dd3a96ef9863f044ad1c71593604ec936ba93801cbb8a915925055781e616", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0b3dd3a96ef9863f044ad1c71593604ec936ba93801cbb8a915925055781e616", kill_on_drop: false }`
[INFO] [stdout] 0b3dd3a96ef9863f044ad1c71593604ec936ba93801cbb8a915925055781e616
