[INFO] cloning repository https://github.com/pedro-stanaka/rustlings
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/pedro-stanaka/rustlings" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpedro-stanaka%2Frustlings", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpedro-stanaka%2Frustlings'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 3b3c6b469718014402765175cbf33b6400bc12e8
[INFO] checking pedro-stanaka/rustlings/3b3c6b469718014402765175cbf33b6400bc12e8 against master#db0e836148accac8a22532e3596ac612b63c2d8e for pr-139272
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpedro-stanaka%2Frustlings" "/workspace/builds/worker-2-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/pedro-stanaka/rustlings on toolchain db0e836148accac8a22532e3596ac612b63c2d8e
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+db0e836148accac8a22532e3596ac612b63c2d8e" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/pedro-stanaka/rustlings
[INFO] finished tweaking git repo https://github.com/pedro-stanaka/rustlings
[INFO] tweaked toml for git repo https://github.com/pedro-stanaka/rustlings written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+db0e836148accac8a22532e3596ac612b63c2d8e" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+db0e836148accac8a22532e3596ac612b63c2d8e" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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:b0b074c097205a61b89e8ad263052f976b2b332c4dc5f02aef1fe52501660d6e" "/opt/rustwide/cargo-home/bin/cargo" "+db0e836148accac8a22532e3596ac612b63c2d8e" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 7786aa700686d9807cb91ec99c5ab893e4cd4201afc2386b4461dc4aee8f8d69
[INFO] running `Command { std: "docker" "start" "-a" "7786aa700686d9807cb91ec99c5ab893e4cd4201afc2386b4461dc4aee8f8d69", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7786aa700686d9807cb91ec99c5ab893e4cd4201afc2386b4461dc4aee8f8d69", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7786aa700686d9807cb91ec99c5ab893e4cd4201afc2386b4461dc4aee8f8d69", kill_on_drop: false }`
[INFO] [stdout] 7786aa700686d9807cb91ec99c5ab893e4cd4201afc2386b4461dc4aee8f8d69
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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:b0b074c097205a61b89e8ad263052f976b2b332c4dc5f02aef1fe52501660d6e" "/opt/rustwide/cargo-home/bin/cargo" "+db0e836148accac8a22532e3596ac612b63c2d8e" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 044596ff4aecb20e09014a9ee5407ccea177caf6d5ff2b48c1176ba226e7ed89
[INFO] running `Command { std: "docker" "start" "-a" "044596ff4aecb20e09014a9ee5407ccea177caf6d5ff2b48c1176ba226e7ed89", kill_on_drop: false }`
[INFO] [stderr]     Checking exercises v0.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> exercises/13_error_handling/errors5.rs:53:44
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn main() {
[INFO] [stdout]    | --------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] 52 |     let pretend_user_input = "42";
[INFO] [stdout] 53 |     let x: i64 = pretend_user_input.parse()?;
[INFO] [stdout]    |                                            ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]    |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn main() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout]    |           +++++++++++++++++++++++++++++++++++++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> exercises/13_error_handling/errors5.rs:54:59
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn main() {
[INFO] [stdout]    | --------- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout] ...
[INFO] [stdout] 54 |     println!("output={:?}", PositiveNonzeroInteger::new(x)?);
[INFO] [stdout]    |                                                           ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout]    |
[INFO] [stdout] help: consider adding return type
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn main() -> Result<(), Box<dyn std::error::Error>> {
[INFO] [stdout]    |           +++++++++++++++++++++++++++++++++++++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0308]: mismatched types
[INFO] [stdout]   --> exercises/13_error_handling/errors5.rs:55:5
[INFO] [stdout]    |
[INFO] [stdout] 51 | fn main() {
[INFO] [stdout]    |          - expected `()` because of default return type
[INFO] [stdout] ...
[INFO] [stdout] 55 |     Ok(())
[INFO] [stdout]    |     ^^^^^^ expected `()`, found `Result<(), _>`
[INFO] [stdout]    |
[INFO] [stdout]    = note: expected unit type `()`
[INFO] [stdout]                    found enum `Result<(), _>`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0308.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stdout] error[E0072]: recursive type `List` has infinite size
[INFO] [stdout]   --> exercises/19_smart_pointers/box1.rs:14:1
[INFO] [stdout]    |
[INFO] [stdout] 14 | enum List {
[INFO] [stdout]    | ^^^^^^^^^
[INFO] [stdout] 15 |     Cons(i32, List),
[INFO] [stdout]    |               ---- recursive without indirection
[INFO] [stdout]    |
[INFO] [stdout] help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to break the cycle
[INFO] [stdout]    |
[INFO] [stdout] 15 |     Cons(i32, Box<List>),
[INFO] [stdout]    |               ++++    +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `exercises` (bin "errors5") due to 3 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0425]: cannot find value `fruit` in module `delicious_snacks`
[INFO] [stdout]   --> exercises/10_modules/modules2.rs:24:27
[INFO] [stdout]    |
[INFO] [stdout] 24 |         delicious_snacks::fruit,
[INFO] [stdout]    |                           ^^^^^ not found in `delicious_snacks`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `veggie` in module `delicious_snacks`
[INFO] [stdout]   --> exercises/10_modules/modules2.rs:25:27
[INFO] [stdout]    |
[INFO] [stdout] 25 |         delicious_snacks::veggie,
[INFO] [stdout]    |                           ^^^^^^ not found in `delicious_snacks`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0425`.
[INFO] [stdout] 
[INFO] [stdout] error[E0391]: cycle detected when computing drop-check constraints for `List`
[INFO] [stdout]   --> exercises/19_smart_pointers/box1.rs:14:1
[INFO] [stdout]    |
[INFO] [stdout] 14 | enum List {
[INFO] [stdout]    | ^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: ...which immediately requires computing drop-check constraints for `List` again
[INFO] [stdout]    = note: cycle used when computing dropck types for `List`
[INFO] [stdout]    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `exercises` (bin "modules2") due to 2 previous errors
[INFO] [stdout] error[E0391]: cycle detected when computing when `List` needs drop
[INFO] [stdout]   --> exercises/19_smart_pointers/box1.rs:14:1
[INFO] [stdout]    |
[INFO] [stdout] 14 | enum List {
[INFO] [stdout]    | ^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: ...which immediately requires computing when `List` needs drop again
[INFO] [stdout]    = note: cycle used when computing whether `List` needs drop
[INFO] [stdout]    = note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0072, E0391.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0072`.
[INFO] [stdout] 
[INFO] [stdout] warning: function `bigger` is never used
[INFO] [stdout]  --> solutions/03_if/if1.rs:1:4
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn bigger(a: i32, b: i32) -> i32 {
[INFO] [stdout]   |    ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `exercises` (bin "box1") due to 3 previous errors
[INFO] [stdout] warning: enum `CreationError` is never used
[INFO] [stdout]   --> exercises/13_error_handling/errors6.rs:10:6
[INFO] [stdout]    |
[INFO] [stdout] 10 | enum CreationError {
[INFO] [stdout]    |      ^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `ParsePosNonzeroError` is never used
[INFO] [stdout]   --> exercises/13_error_handling/errors6.rs:17:6
[INFO] [stdout]    |
[INFO] [stdout] 17 | enum ParsePosNonzeroError {
[INFO] [stdout]    |      ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function `from_creation` is never used
[INFO] [stdout]   --> exercises/13_error_handling/errors6.rs:23:8
[INFO] [stdout]    |
[INFO] [stdout] 22 | impl ParsePosNonzeroError {
[INFO] [stdout]    | ------------------------- associated function in this implementation
[INFO] [stdout] 23 |     fn from_creation(err: CreationError) -> Self {
[INFO] [stdout]    |        ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `PositiveNonzeroInteger` is never constructed
[INFO] [stdout]   --> exercises/13_error_handling/errors6.rs:32:8
[INFO] [stdout]    |
[INFO] [stdout] 32 | struct PositiveNonzeroInteger(u64);
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated functions `new` and `parse` are never used
[INFO] [stdout]   --> exercises/13_error_handling/errors6.rs:35:8
[INFO] [stdout]    |
[INFO] [stdout] 34 | impl PositiveNonzeroInteger {
[INFO] [stdout]    | --------------------------- associated functions in this implementation
[INFO] [stdout] 35 |     fn new(value: i64) -> Result<Self, CreationError> {
[INFO] [stdout]    |        ^^^
[INFO] [stdout] ...
[INFO] [stdout] 43 |     fn parse(s: &str) -> Result<Self, ParsePosNonzeroError> {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "044596ff4aecb20e09014a9ee5407ccea177caf6d5ff2b48c1176ba226e7ed89", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "044596ff4aecb20e09014a9ee5407ccea177caf6d5ff2b48c1176ba226e7ed89", kill_on_drop: false }`
[INFO] [stdout] 044596ff4aecb20e09014a9ee5407ccea177caf6d5ff2b48c1176ba226e7ed89