[INFO] fetching crate cain 0.1.2...
[INFO] checking cain-0.1.2 against master#80399064afa4a2cd153f30d02c25f7ea0383ed65 for opaque-soundness-fix
[INFO] extracting crate cain 0.1.2 into /workspace/builds/worker-7-tc1/source
[INFO] validating manifest of crates.io crate cain 0.1.2 on toolchain 80399064afa4a2cd153f30d02c25f7ea0383ed65
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+80399064afa4a2cd153f30d02c25f7ea0383ed65" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate cain 0.1.2
[INFO] finished tweaking crates.io crate cain 0.1.2
[INFO] tweaked toml for crates.io crate cain 0.1.2 written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+80399064afa4a2cd153f30d02c25f7ea0383ed65" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+80399064afa4a2cd153f30d02c25f7ea0383ed65" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+80399064afa4a2cd153f30d02c25f7ea0383ed65" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 89f29193c80e998d63804eacf445449a3a4102a6c7d1b705254c3815485a1a54
[INFO] running `Command { std: "docker" "start" "-a" "89f29193c80e998d63804eacf445449a3a4102a6c7d1b705254c3815485a1a54", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "89f29193c80e998d63804eacf445449a3a4102a6c7d1b705254c3815485a1a54", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "89f29193c80e998d63804eacf445449a3a4102a6c7d1b705254c3815485a1a54", kill_on_drop: false }`
[INFO] [stdout] 89f29193c80e998d63804eacf445449a3a4102a6c7d1b705254c3815485a1a54
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+80399064afa4a2cd153f30d02c25f7ea0383ed65" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e5037a3dbf1fd456b71f8c2a07fc50ad91354d14ffa993794e8bbfd8c926dca8
[INFO] running `Command { std: "docker" "start" "-a" "e5037a3dbf1fd456b71f8c2a07fc50ad91354d14ffa993794e8bbfd8c926dca8", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.79
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]     Checking unicode-ident v1.0.12
[INFO] [stderr]     Checking diff v0.1.13
[INFO] [stderr]     Checking yansi v0.5.1
[INFO] [stderr]     Checking pretty_assertions v1.4.0
[INFO] [stderr]     Checking quote v1.0.35
[INFO] [stderr]     Checking cain v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:31:30
[INFO] [stdout]    |
[INFO] [stdout] 31 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:56:30
[INFO] [stdout]    |
[INFO] [stdout] 56 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:56:30
[INFO] [stdout]    |
[INFO] [stdout] 56 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:56:30
[INFO] [stdout]    |
[INFO] [stdout] 56 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:49:30
[INFO] [stdout]    |
[INFO] [stdout] 49 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:56:30
[INFO] [stdout]    |
[INFO] [stdout] 56 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> tests/diverging_branches.rs:26:25
[INFO] [stdout]    |
[INFO] [stdout] 26 |                     let x = match n {
[INFO] [stdout]    |                         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> tests/diverging_branches.rs:52:25
[INFO] [stdout]    |
[INFO] [stdout] 52 |                     let y = match n % 2 {
[INFO] [stdout]    |                         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> tests/diverging_branches.rs:44:25
[INFO] [stdout]    |
[INFO] [stdout] 44 |                     let x = match n % 3 {
[INFO] [stdout]    |                         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> tests/no_behavior_change.rs:64:22
[INFO] [stdout]    |
[INFO] [stdout] 64 |                 Some(mut v) => { v.pop(); },
[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]   --> tests/no_behavior_change.rs:78:22
[INFO] [stdout]    |
[INFO] [stdout] 78 |                 Some(mut b) => inc(&mut b),
[INFO] [stdout]    |                      ----^
[INFO] [stdout]    |                      |
[INFO] [stdout]    |                      help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> tests/no_behavior_change.rs:109:22
[INFO] [stdout]     |
[INFO] [stdout] 109 |                 Some(mut b) => inc(&mut b),
[INFO] [stdout]     |                      ----^
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> tests/no_behavior_change.rs:140:26
[INFO] [stdout]     |
[INFO] [stdout] 140 |                 Some(ref mut b) => inc(b),
[INFO] [stdout]     |                          ----^
[INFO] [stdout]     |                          |
[INFO] [stdout]     |                          help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> tests/no_behavior_change.rs:154:37
[INFO] [stdout]     |
[INFO] [stdout] 154 |             let _ = if let Some(ref mut b) = &mut a {
[INFO] [stdout]     |                                     ----^
[INFO] [stdout]     |                                     |
[INFO] [stdout]     |                                     help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 9 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: irrefutable `if let` pattern
[INFO] [stdout]    --> tests/no_behavior_change.rs:179:16
[INFO] [stdout]     |
[INFO] [stdout] 179 |             if let None = a {
[INFO] [stdout]     |                ^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this pattern will always match, so the `if let` is useless
[INFO] [stdout]     = help: consider replacing the `if let` with a `let`
[INFO] [stdout]     = note: `#[warn(irrefutable_let_patterns)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 7.31s
[INFO] running `Command { std: "docker" "inspect" "e5037a3dbf1fd456b71f8c2a07fc50ad91354d14ffa993794e8bbfd8c926dca8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e5037a3dbf1fd456b71f8c2a07fc50ad91354d14ffa993794e8bbfd8c926dca8", kill_on_drop: false }`
[INFO] [stdout] e5037a3dbf1fd456b71f8c2a07fc50ad91354d14ffa993794e8bbfd8c926dca8
[INFO] checking cain-0.1.2 against master#09bc67b9158392361780e779d32997f14cc75c39 for opaque-soundness-fix
[INFO] extracting crate cain 0.1.2 into /workspace/builds/worker-7-tc2/source
[INFO] validating manifest of crates.io crate cain 0.1.2 on toolchain 09bc67b9158392361780e779d32997f14cc75c39
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+09bc67b9158392361780e779d32997f14cc75c39" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate cain 0.1.2
[INFO] finished tweaking crates.io crate cain 0.1.2
[INFO] tweaked toml for crates.io crate cain 0.1.2 written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+09bc67b9158392361780e779d32997f14cc75c39" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+09bc67b9158392361780e779d32997f14cc75c39" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+09bc67b9158392361780e779d32997f14cc75c39" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 71338f68610e2e74f5941737d5ead8bfa9c3d64b86562a268c11cf08faadaa34
[INFO] running `Command { std: "docker" "start" "-a" "71338f68610e2e74f5941737d5ead8bfa9c3d64b86562a268c11cf08faadaa34", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "71338f68610e2e74f5941737d5ead8bfa9c3d64b86562a268c11cf08faadaa34", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "71338f68610e2e74f5941737d5ead8bfa9c3d64b86562a268c11cf08faadaa34", kill_on_drop: false }`
[INFO] [stdout] 71338f68610e2e74f5941737d5ead8bfa9c3d64b86562a268c11cf08faadaa34
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+09bc67b9158392361780e779d32997f14cc75c39" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] da0774d2ba6a591d9127f57c62db5beacc1c6586a3f8d264f7eea4425c8c5d5f
[INFO] running `Command { std: "docker" "start" "-a" "da0774d2ba6a591d9127f57c62db5beacc1c6586a3f8d264f7eea4425c8c5d5f", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.79
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]     Checking unicode-ident v1.0.12
[INFO] [stderr]     Checking diff v0.1.13
[INFO] [stderr]     Checking yansi v0.5.1
[INFO] [stderr]     Checking pretty_assertions v1.4.0
[INFO] [stderr]     Checking quote v1.0.35
[INFO] [stderr]     Checking cain v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:31:30
[INFO] [stdout]    |
[INFO] [stdout] 31 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:56:30
[INFO] [stdout]    |
[INFO] [stdout] 56 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:56:30
[INFO] [stdout]    |
[INFO] [stdout] 56 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:56:30
[INFO] [stdout]    |
[INFO] [stdout] 56 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:49:30
[INFO] [stdout]    |
[INFO] [stdout] 49 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> tests/diverging_branches.rs:56:30
[INFO] [stdout]    |
[INFO] [stdout] 56 |                         _ => panic!() as &str,
[INFO] [stdout]    |                              --------^^^^^^^^
[INFO] [stdout]    |                              |
[INFO] [stdout]    |                              unreachable expression
[INFO] [stdout]    |                              any code following this expression is unreachable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> tests/diverging_branches.rs:26:25
[INFO] [stdout]    |
[INFO] [stdout] 26 |                     let x = match n {
[INFO] [stdout]    |                         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> tests/diverging_branches.rs:52:25
[INFO] [stdout]    |
[INFO] [stdout] 52 |                     let y = match n % 2 {
[INFO] [stdout]    |                         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> tests/diverging_branches.rs:44:25
[INFO] [stdout]    |
[INFO] [stdout] 44 |                     let x = match n % 3 {
[INFO] [stdout]    |                         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 9 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> tests/no_behavior_change.rs:64:22
[INFO] [stdout]    |
[INFO] [stdout] 64 |                 Some(mut v) => { v.pop(); },
[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]   --> tests/no_behavior_change.rs:78:22
[INFO] [stdout]    |
[INFO] [stdout] 78 |                 Some(mut b) => inc(&mut b),
[INFO] [stdout]    |                      ----^
[INFO] [stdout]    |                      |
[INFO] [stdout]    |                      help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> tests/no_behavior_change.rs:109:22
[INFO] [stdout]     |
[INFO] [stdout] 109 |                 Some(mut b) => inc(&mut b),
[INFO] [stdout]     |                      ----^
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> tests/no_behavior_change.rs:140:26
[INFO] [stdout]     |
[INFO] [stdout] 140 |                 Some(ref mut b) => inc(b),
[INFO] [stdout]     |                          ----^
[INFO] [stdout]     |                          |
[INFO] [stdout]     |                          help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> tests/no_behavior_change.rs:154:37
[INFO] [stdout]     |
[INFO] [stdout] 154 |             let _ = if let Some(ref mut b) = &mut a {
[INFO] [stdout]     |                                     ----^
[INFO] [stdout]     |                                     |
[INFO] [stdout]     |                                     help: remove this `mut`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: irrefutable `if let` pattern
[INFO] [stdout]    --> tests/no_behavior_change.rs:179:16
[INFO] [stdout]     |
[INFO] [stdout] 179 |             if let None = a {
[INFO] [stdout]     |                ^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this pattern will always match, so the `if let` is useless
[INFO] [stdout]     = help: consider replacing the `if let` with a `let`
[INFO] [stdout]     = note: `#[warn(irrefutable_let_patterns)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 7.27s
[INFO] running `Command { std: "docker" "inspect" "da0774d2ba6a591d9127f57c62db5beacc1c6586a3f8d264f7eea4425c8c5d5f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "da0774d2ba6a591d9127f57c62db5beacc1c6586a3f8d264f7eea4425c8c5d5f", kill_on_drop: false }`
[INFO] [stdout] da0774d2ba6a591d9127f57c62db5beacc1c6586a3f8d264f7eea4425c8c5d5f
