[INFO] cloning repository https://github.com/n4to4/rust-for-rustaceans
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/n4to4/rust-for-rustaceans" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fn4to4%2Frust-for-rustaceans", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fn4to4%2Frust-for-rustaceans'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 6b94d26fd680e2301f28a46bd7295a9d0589d708
[INFO] checking n4to4/rust-for-rustaceans against 1.55.0 for beta-1.56-3
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fn4to4%2Frust-for-rustaceans" "/workspace/builds/worker-96/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-96/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/n4to4/rust-for-rustaceans on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/n4to4/rust-for-rustaceans
[INFO] finished tweaking git repo https://github.com/n4to4/rust-for-rustaceans
[INFO] tweaked toml for git repo https://github.com/n4to4/rust-for-rustaceans written to /workspace/builds/worker-96/source/Cargo.toml
[INFO] crate git repo https://github.com/n4to4/rust-for-rustaceans already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-96/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-96/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8df925fdf4726ddac9ee61a6c966fea22e3f38313ee6738b20002f7e1a9668ee
[INFO] running `Command { std: "docker" "start" "-a" "8df925fdf4726ddac9ee61a6c966fea22e3f38313ee6738b20002f7e1a9668ee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8df925fdf4726ddac9ee61a6c966fea22e3f38313ee6738b20002f7e1a9668ee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8df925fdf4726ddac9ee61a6c966fea22e3f38313ee6738b20002f7e1a9668ee", kill_on_drop: false }`
[INFO] [stdout] 8df925fdf4726ddac9ee61a6c966fea22e3f38313ee6738b20002f7e1a9668ee
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-96/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-96/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=warn" "-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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c89fbae88ec911267f20c2d357332a76bcd47a4d1529d144825644bda476fd6c
[INFO] running `Command { std: "docker" "start" "-a" "c89fbae88ec911267f20c2d357332a76bcd47a4d1529d144825644bda476fd6c", kill_on_drop: false }`
[INFO] [stderr]     Checking chapter02 v0.1.0 (/opt/rustwide/workdir/chapter02)
[INFO] [stderr]     Checking chapter03 v0.1.0 (/opt/rustwide/workdir/chapter03)
[INFO] [stderr]     Checking chapter04 v0.1.0 (/opt/rustwide/workdir/chapter04)
[INFO] [stderr]     Checking rust-for-rustaceans v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: private trait `TraitBounds` in public interface (error E0445)
[INFO] [stdout]   --> chapter04/src/main.rs:44:5
[INFO] [stdout]    |
[INFO] [stdout] 44 |     impl<T> Sealed for T where T: TraitBounds {}
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(private_in_public)]` on by default
[INFO] [stdout]    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
[INFO] [stdout]    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `var1`
[INFO] [stdout]  --> chapter02/src/main.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let var1 = &x;
[INFO] [stdout]   |         ^^^^ help: if this is intentional, prefix it with an underscore: `_var1`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `var2` is assigned to, but never used
[INFO] [stdout]  --> chapter02/src/main.rs:9:13
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let mut var2 = &x;
[INFO] [stdout]   |             ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: consider using `_var2` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `var2` is never read
[INFO] [stdout]   --> chapter02/src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     var2 = &y;
[INFO] [stdout]    |     ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> chapter02/src/main.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 18 |     let y = &x;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `x` is never read
[INFO] [stdout]   --> chapter02/src/main.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     x = 43;
[INFO] [stdout]    |     ^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> chapter02/src/main.rs:27:13
[INFO] [stdout]    |
[INFO] [stdout] 27 |         let z = (x1, y1);
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x2`
[INFO] [stdout]   --> chapter02/src/main.rs:29:9
[INFO] [stdout]    |
[INFO] [stdout] 29 |     let x2 = x1;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_x2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: private trait `TraitBounds` in public interface (error E0445)
[INFO] [stdout]   --> chapter04/src/main.rs:46:1
[INFO] [stdout]    |
[INFO] [stdout] 46 | impl<T> CanUseCannotImplement for T where T: TraitBounds {}
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
[INFO] [stdout]    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `var1`
[INFO] [stdout]  --> chapter02/src/main.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let var1 = &x;
[INFO] [stdout]   |         ^^^^ help: if this is intentional, prefix it with an underscore: `_var1`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0502]: cannot borrow `s` as immutable because it is also borrowed as mutable
[INFO] [stdout]   --> chapter02/src/main.rs:74:20
[INFO] [stdout]    |
[INFO] [stdout] 73 |     *MutStr { s: &mut s }.s = "world";
[INFO] [stdout]    |                  ------ mutable borrow occurs here
[INFO] [stdout] 74 |     println!("{}", s);
[INFO] [stdout]    |                    ^
[INFO] [stdout]    |                    |
[INFO] [stdout]    |                    immutable borrow occurs here
[INFO] [stdout]    |                    mutable borrow later used here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0502`.
[INFO] [stdout] 
[INFO] [stdout] warning: variable `var2` is assigned to, but never used
[INFO] [stdout]  --> chapter02/src/main.rs:9:13
[INFO] [stdout]   |
[INFO] [stdout] 9 |     let mut var2 = &x;
[INFO] [stdout]   |             ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: consider using `_var2` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `var2` is never read
[INFO] [stdout]   --> chapter02/src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     var2 = &y;
[INFO] [stdout]    |     ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_assignments)]` on by default
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> chapter02/src/main.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 18 |     let y = &x;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: value assigned to `x` is never read
[INFO] [stdout]   --> chapter02/src/main.rs:19:5
[INFO] [stdout]    |
[INFO] [stdout] 19 |     x = 43;
[INFO] [stdout]    |     ^
[INFO] [stdout]    |
[INFO] [stdout]    = help: maybe it is overwritten before being read?
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `z`
[INFO] [stdout]   --> chapter02/src/main.rs:27:13
[INFO] [stdout]    |
[INFO] [stdout] 27 |         let z = (x1, y1);
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_z`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x2`
[INFO] [stdout]   --> chapter02/src/main.rs:29:9
[INFO] [stdout]    |
[INFO] [stdout] 29 |     let x2 = x1;
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_x2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0502]: cannot borrow `s` as immutable because it is also borrowed as mutable
[INFO] [stdout]   --> chapter02/src/main.rs:74:20
[INFO] [stdout]    |
[INFO] [stdout] 73 |     *MutStr { s: &mut s }.s = "world";
[INFO] [stdout]    |                  ------ mutable borrow occurs here
[INFO] [stdout] 74 |     println!("{}", s);
[INFO] [stdout]    |                    ^
[INFO] [stdout]    |                    |
[INFO] [stdout]    |                    immutable borrow occurs here
[INFO] [stdout]    |                    mutable borrow later used here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0502`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `chapter02` due to 2 previous errors; 7 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: private trait `TraitBounds` in public interface (error E0445)
[INFO] [stdout]   --> chapter04/src/main.rs:44:5
[INFO] [stdout]    |
[INFO] [stdout] 44 |     impl<T> Sealed for T where T: TraitBounds {}
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(private_in_public)]` on by default
[INFO] [stdout]    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
[INFO] [stdout]    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: private trait `TraitBounds` in public interface (error E0445)
[INFO] [stdout]   --> chapter04/src/main.rs:46:1
[INFO] [stdout]    |
[INFO] [stdout] 46 | impl<T> CanUseCannotImplement for T where T: TraitBounds {}
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
[INFO] [stdout]    = note: for more information, see issue #34537 <https://github.com/rust-lang/rust/issues/34537>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "c89fbae88ec911267f20c2d357332a76bcd47a4d1529d144825644bda476fd6c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c89fbae88ec911267f20c2d357332a76bcd47a4d1529d144825644bda476fd6c", kill_on_drop: false }`
[INFO] [stdout] c89fbae88ec911267f20c2d357332a76bcd47a4d1529d144825644bda476fd6c
