[INFO] fetching crate failure 0.1.8...
[INFO] checking failure-0.1.8 against master#385fa9d845dd326c6bbfd58c22244215e431948a for absurd-question-mark-desugar
[INFO] extracting crate failure 0.1.8 into /workspace/builds/worker-4-tc1/source
[INFO] validating manifest of crates.io crate failure 0.1.8 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 crates.io crate failure 0.1.8
[INFO] finished tweaking crates.io crate failure 0.1.8
[INFO] tweaked toml for crates.io crate failure 0.1.8 written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] crate crates.io crate failure 0.1.8 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]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded failure_derive v0.1.7
[INFO] [stderr]   Downloaded synstructure v0.12.3
[INFO] [stderr]   Downloaded cc v1.0.52
[INFO] [stderr]   Downloaded backtrace v0.3.46
[INFO] [stderr]   Downloaded backtrace-sys v0.1.37
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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] db6d0bb9ab6c36a81f6014047e7e7ff5a9821532cf17cfe029320c7a39d88e97
[INFO] running `Command { std: "docker" "start" "-a" "db6d0bb9ab6c36a81f6014047e7e7ff5a9821532cf17cfe029320c7a39d88e97", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "db6d0bb9ab6c36a81f6014047e7e7ff5a9821532cf17cfe029320c7a39d88e97", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "db6d0bb9ab6c36a81f6014047e7e7ff5a9821532cf17cfe029320c7a39d88e97", kill_on_drop: false }`
[INFO] [stdout] db6d0bb9ab6c36a81f6014047e7e7ff5a9821532cf17cfe029320c7a39d88e97
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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] ab673da1036fdacdaf17c4906c7862b76750245faeedf028d34dfca8267efca9
[INFO] running `Command { std: "docker" "start" "-a" "ab673da1036fdacdaf17c4906c7862b76750245faeedf028d34dfca8267efca9", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.12
[INFO] [stderr]    Compiling unicode-xid v0.2.0
[INFO] [stderr]    Compiling cc v1.0.52
[INFO] [stderr]    Compiling syn v1.0.18
[INFO] [stderr]    Compiling libc v0.2.69
[INFO] [stderr]    Compiling failure_derive v0.1.7
[INFO] [stderr]     Checking rustc-demangle v0.1.16
[INFO] [stderr]    Compiling quote v1.0.4
[INFO] [stderr]    Compiling backtrace-sys v0.1.37
[INFO] [stderr]     Checking backtrace v0.3.46
[INFO] [stderr]    Compiling synstructure v0.12.3
[INFO] [stderr]     Checking failure v0.1.8 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> examples/simple.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[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]  --> examples/error_as_cause.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[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]  --> tests/basic_fail.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[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]  --> tests/fail_compat.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> examples/error_as_cause.rs:15:18
[INFO] [stdout]    |
[INFO] [stdout] 15 |     for cause in Fail::iter_causes(&bad_function().unwrap_err()) {
[INFO] [stdout]    |                  ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 15 |     for cause in <dyn Fail>::iter_causes(&bad_function().unwrap_err()) {
[INFO] [stdout]    |                  ++++     +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> examples/simple.rs:19:18
[INFO] [stdout]    |
[INFO] [stdout] 19 |     for cause in Fail::iter_chain(&bad_function().unwrap_err()) {
[INFO] [stdout]    |                  ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 19 |     for cause in <dyn Fail>::iter_chain(&bad_function().unwrap_err()) {
[INFO] [stdout]    |                  ++++     +
[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] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> examples/string_custom_error_pattern.rs:38:32
[INFO] [stdout]    |
[INFO] [stdout] 38 |     fn cause(&self) -> Option<&Fail> {
[INFO] [stdout]    |                                ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 38 |     fn cause(&self) -> Option<&dyn Fail> {
[INFO] [stdout]    |                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> examples/string_custom_error_pattern.rs:13:18
[INFO] [stdout]    |
[INFO] [stdout] 13 |     for cause in Fail::iter_causes(&err) {
[INFO] [stdout]    |                  ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 13 |     for cause in <dyn Fail>::iter_causes(&err) {
[INFO] [stdout]    |                  ++++     +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 4.69s
[INFO] running `Command { std: "docker" "inspect" "ab673da1036fdacdaf17c4906c7862b76750245faeedf028d34dfca8267efca9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ab673da1036fdacdaf17c4906c7862b76750245faeedf028d34dfca8267efca9", kill_on_drop: false }`
[INFO] [stdout] ab673da1036fdacdaf17c4906c7862b76750245faeedf028d34dfca8267efca9
[INFO] checking failure-0.1.8 against try#645bb72776a6a56a1a8f52631a44bd082b2ba509 for absurd-question-mark-desugar
[INFO] extracting crate failure 0.1.8 into /workspace/builds/worker-4-tc2/source
[INFO] validating manifest of crates.io crate failure 0.1.8 on toolchain 645bb72776a6a56a1a8f52631a44bd082b2ba509
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+645bb72776a6a56a1a8f52631a44bd082b2ba509" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate failure 0.1.8
[INFO] finished tweaking crates.io crate failure 0.1.8
[INFO] tweaked toml for crates.io crate failure 0.1.8 written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] crate crates.io crate failure 0.1.8 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" "+645bb72776a6a56a1a8f52631a44bd082b2ba509" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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" "+645bb72776a6a56a1a8f52631a44bd082b2ba509" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 81164743c4d0d71e521d1c64e0d7bb4bd4de6852b5bcbdf134fe2f885cbe2bbb
[INFO] running `Command { std: "docker" "start" "-a" "81164743c4d0d71e521d1c64e0d7bb4bd4de6852b5bcbdf134fe2f885cbe2bbb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "81164743c4d0d71e521d1c64e0d7bb4bd4de6852b5bcbdf134fe2f885cbe2bbb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "81164743c4d0d71e521d1c64e0d7bb4bd4de6852b5bcbdf134fe2f885cbe2bbb", kill_on_drop: false }`
[INFO] [stdout] 81164743c4d0d71e521d1c64e0d7bb4bd4de6852b5bcbdf134fe2f885cbe2bbb
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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" "+645bb72776a6a56a1a8f52631a44bd082b2ba509" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4382d33da35b55afa72192cff0d5928d7e9ab3d3fc6cd3fb8438e84c93139f91
[INFO] running `Command { std: "docker" "start" "-a" "4382d33da35b55afa72192cff0d5928d7e9ab3d3fc6cd3fb8438e84c93139f91", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.12
[INFO] [stderr]    Compiling unicode-xid v0.2.0
[INFO] [stderr]    Compiling libc v0.2.69
[INFO] [stderr]    Compiling syn v1.0.18
[INFO] [stderr]    Compiling cc v1.0.52
[INFO] [stderr]    Compiling failure_derive v0.1.7
[INFO] [stderr]     Checking rustc-demangle v0.1.16
[INFO] [stderr]    Compiling backtrace-sys v0.1.37
[INFO] [stderr]    Compiling quote v1.0.4
[INFO] [stderr]     Checking backtrace v0.3.46
[INFO] [stderr]    Compiling synstructure v0.12.3
[INFO] [stderr]     Checking failure v0.1.8 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> tests/fail_compat.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[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]  --> examples/simple.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> examples/string_custom_error_pattern.rs:38:32
[INFO] [stdout]    |
[INFO] [stdout] 38 |     fn cause(&self) -> Option<&Fail> {
[INFO] [stdout]    |                                ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 38 |     fn cause(&self) -> Option<&dyn Fail> {
[INFO] [stdout]    |                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> examples/string_custom_error_pattern.rs:13:18
[INFO] [stdout]    |
[INFO] [stdout] 13 |     for cause in Fail::iter_causes(&err) {
[INFO] [stdout]    |                  ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 13 |     for cause in <dyn Fail>::iter_causes(&err) {
[INFO] [stdout]    |                  ++++     +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> examples/error_as_cause.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> examples/simple.rs:19:18
[INFO] [stdout]    |
[INFO] [stdout] 19 |     for cause in Fail::iter_chain(&bad_function().unwrap_err()) {
[INFO] [stdout]    |                  ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 19 |     for cause in <dyn Fail>::iter_chain(&bad_function().unwrap_err()) {
[INFO] [stdout]    |                  ++++     +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> tests/basic_fail.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> examples/error_as_cause.rs:15:18
[INFO] [stdout]    |
[INFO] [stdout] 15 |     for cause in Fail::iter_causes(&bad_function().unwrap_err()) {
[INFO] [stdout]    |                  ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 15 |     for cause in <dyn Fail>::iter_causes(&bad_function().unwrap_err()) {
[INFO] [stdout]    |                  ++++     +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[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] [stdout] warning: 2 warnings 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 3.94s
[INFO] running `Command { std: "docker" "inspect" "4382d33da35b55afa72192cff0d5928d7e9ab3d3fc6cd3fb8438e84c93139f91", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4382d33da35b55afa72192cff0d5928d7e9ab3d3fc6cd3fb8438e84c93139f91", kill_on_drop: false }`
[INFO] [stdout] 4382d33da35b55afa72192cff0d5928d7e9ab3d3fc6cd3fb8438e84c93139f91