[INFO] cloning repository https://github.com/brennie/picasso
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/brennie/picasso" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbrennie%2Fpicasso", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbrennie%2Fpicasso'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] adb5c673dc9f5f8da6d6dd88a24a62db2fb72d22
[INFO] checking brennie/picasso against master#385fa9d845dd326c6bbfd58c22244215e431948a for never-type-fallback-to-never
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbrennie%2Fpicasso" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/brennie/picasso on toolchain 385fa9d845dd326c6bbfd58c22244215e431948a
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/brennie/picasso
[INFO] finished tweaking git repo https://github.com/brennie/picasso
[INFO] tweaked toml for git repo https://github.com/brennie/picasso written to /workspace/builds/worker-1-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/brennie/picasso 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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded syn v0.14.2
[INFO] [stderr]   Downloaded quote v0.6.3
[INFO] [stderr]   Downloaded proc-macro2 v0.4.6
[INFO] [stderr]   Downloaded rand_core v0.2.1
[INFO] [stderr]   Downloaded rand v0.5.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d48b919c1b389a1bd0d92fa78dc3d6cbc260b73a68b205df268c775ff82564bb
[INFO] running `Command { std: "docker" "start" "-a" "d48b919c1b389a1bd0d92fa78dc3d6cbc260b73a68b205df268c775ff82564bb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d48b919c1b389a1bd0d92fa78dc3d6cbc260b73a68b205df268c775ff82564bb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d48b919c1b389a1bd0d92fa78dc3d6cbc260b73a68b205df268c775ff82564bb", kill_on_drop: false }`
[INFO] [stdout] d48b919c1b389a1bd0d92fa78dc3d6cbc260b73a68b205df268c775ff82564bb
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 30b4f3dee07890bdfcd4630aa9743ec1c7d93e2c301b336729d3ce2b28a4aa4f
[INFO] running `Command { std: "docker" "start" "-a" "30b4f3dee07890bdfcd4630aa9743ec1c7d93e2c301b336729d3ce2b28a4aa4f", kill_on_drop: false }`
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]     Checking libc v0.2.42
[INFO] [stderr]     Checking unicode-width v0.1.5
[INFO] [stderr]     Checking vec_map v0.8.1
[INFO] [stderr]     Checking bitflags v1.0.3
[INFO] [stderr]     Checking ansi_term v0.11.0
[INFO] [stderr]     Checking strsim v0.7.0
[INFO] [stderr]     Checking rand_core v0.2.1
[INFO] [stderr]    Compiling proc-macro2 v0.4.6
[INFO] [stderr]     Checking textwrap v0.9.0
[INFO] [stderr]     Checking atty v0.2.10
[INFO] [stderr]     Checking rand v0.5.1
[INFO] [stderr]     Checking clap v2.31.2
[INFO] [stderr]    Compiling quote v0.6.3
[INFO] [stderr]    Compiling syn v0.14.2
[INFO] [stderr]    Compiling structopt-derive v0.2.10
[INFO] [stderr]     Checking structopt v0.2.10
[INFO] [stderr]     Checking picasso v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/main.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/main.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 5.49s
[INFO] [stderr] warning: the following packages contain code that will be rejected by a future version of Rust: syn v0.14.2
[INFO] [stderr] note: to see what the problems were, use the option `--future-incompat-report`, or run `cargo report future-incompatibilities --id 1`
[INFO] running `Command { std: "docker" "inspect" "30b4f3dee07890bdfcd4630aa9743ec1c7d93e2c301b336729d3ce2b28a4aa4f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "30b4f3dee07890bdfcd4630aa9743ec1c7d93e2c301b336729d3ce2b28a4aa4f", kill_on_drop: false }`
[INFO] [stdout] 30b4f3dee07890bdfcd4630aa9743ec1c7d93e2c301b336729d3ce2b28a4aa4f
[INFO] checking brennie/picasso against try#2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2 for never-type-fallback-to-never
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fbrennie%2Fpicasso" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/brennie/picasso on toolchain 2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/brennie/picasso
[INFO] finished tweaking git repo https://github.com/brennie/picasso
[INFO] tweaked toml for git repo https://github.com/brennie/picasso written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/brennie/picasso 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" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f847c2bc1adb5d7f40fa2e7a727f0275d591cd57a2586039595399c9506f4b7a
[INFO] running `Command { std: "docker" "start" "-a" "f847c2bc1adb5d7f40fa2e7a727f0275d591cd57a2586039595399c9506f4b7a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f847c2bc1adb5d7f40fa2e7a727f0275d591cd57a2586039595399c9506f4b7a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f847c2bc1adb5d7f40fa2e7a727f0275d591cd57a2586039595399c9506f4b7a", kill_on_drop: false }`
[INFO] [stdout] f847c2bc1adb5d7f40fa2e7a727f0275d591cd57a2586039595399c9506f4b7a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 102d0f38702da9185aa6f818cac51813e9f01ace7d36f18b4d1b94cc67862757
[INFO] running `Command { std: "docker" "start" "-a" "102d0f38702da9185aa6f818cac51813e9f01ace7d36f18b4d1b94cc67862757", kill_on_drop: false }`
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]     Checking libc v0.2.42
[INFO] [stderr]     Checking unicode-width v0.1.5
[INFO] [stderr]     Checking strsim v0.7.0
[INFO] [stderr]     Checking ansi_term v0.11.0
[INFO] [stderr]     Checking bitflags v1.0.3
[INFO] [stderr]     Checking vec_map v0.8.1
[INFO] [stderr]     Checking rand_core v0.2.1
[INFO] [stderr]    Compiling proc-macro2 v0.4.6
[INFO] [stderr]     Checking textwrap v0.9.0
[INFO] [stderr]    Compiling quote v0.6.3
[INFO] [stderr]     Checking atty v0.2.10
[INFO] [stderr]     Checking rand v0.5.1
[INFO] [stderr]    Compiling syn v0.14.2
[INFO] [stderr]     Checking clap v2.31.2
[INFO] [stderr]    Compiling structopt-derive v0.2.10
[INFO] [stderr]     Checking structopt v0.2.10
[INFO] [stderr]     Checking picasso v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/main.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/main.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: a value of type `!` cannot be built from an iterator over elements of type `()`
[INFO] [stdout]    --> src/puzzle.rs:111:32
[INFO] [stdout]     |
[INFO] [stdout] 111 |                     .collect::<Result<_, _>>()?;
[INFO] [stdout]     |                      -------   ^^^^^^^^^^^^ value of type `!` cannot be built from `std::iter::Iterator<Item=()>`
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      required by a bound introduced by this call
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromIterator<()>` is not implemented for `!`, which is required by `Result<_, _>: FromIterator<Result<(), std::fmt::Error>>`
[INFO] [stdout]     = help: the trait `FromIterator<Result<A, E>>` is implemented for `Result<V, E>`
[INFO] [stdout]     = note: this error might have been caused by changes to Rust's type-inference algorithm (see issue #48950 <https://github.com/rust-lang/rust/issues/48950> for more information)
[INFO] [stdout]     = help: did you intend to use the type `()` here instead?
[INFO] [stdout]     = note: required for `Result<!, std::fmt::Error>` to implement `FromIterator<Result<(), std::fmt::Error>>`
[INFO] [stdout] note: required by a bound in `collect`
[INFO] [stdout]    --> /rustc/2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2/library/core/src/iter/traits/iterator.rs:1999:5
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: a value of type `!` cannot be built from an iterator over elements of type `()`
[INFO] [stdout]    --> src/puzzle.rs:111:32
[INFO] [stdout]     |
[INFO] [stdout] 111 |                     .collect::<Result<_, _>>()?;
[INFO] [stdout]     |                      -------   ^^^^^^^^^^^^ value of type `!` cannot be built from `std::iter::Iterator<Item=()>`
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      required by a bound introduced by this call
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromIterator<()>` is not implemented for `!`, which is required by `Result<_, _>: FromIterator<Result<(), std::fmt::Error>>`
[INFO] [stdout]     = help: the trait `FromIterator<Result<A, E>>` is implemented for `Result<V, E>`
[INFO] [stdout]     = note: this error might have been caused by changes to Rust's type-inference algorithm (see issue #48950 <https://github.com/rust-lang/rust/issues/48950> for more information)
[INFO] [stdout]     = help: did you intend to use the type `()` here instead?
[INFO] [stdout]     = note: required for `Result<!, std::fmt::Error>` to implement `FromIterator<Result<(), std::fmt::Error>>`
[INFO] [stdout] note: required by a bound in `collect`
[INFO] [stdout]    --> /rustc/2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2/library/core/src/iter/traits/iterator.rs:1999:5
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 1 previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `picasso` (bin "picasso" test) due to 2 previous errors; 1 warning emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error: aborting due to 1 previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `picasso` (bin "picasso") due to 2 previous errors; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "102d0f38702da9185aa6f818cac51813e9f01ace7d36f18b4d1b94cc67862757", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "102d0f38702da9185aa6f818cac51813e9f01ace7d36f18b4d1b94cc67862757", kill_on_drop: false }`
[INFO] [stdout] 102d0f38702da9185aa6f818cac51813e9f01ace7d36f18b4d1b94cc67862757