[INFO] fetching crate serde_str_helpers 0.1.2...
[INFO] checking serde_str_helpers-0.1.2 against try#4f260f0f20b3133d20cfb50353c0221943af5796+rustflags=-Dunmustuse_in_always_ok for pr-148577
[INFO] extracting crate serde_str_helpers 0.1.2 into /workspace/builds/worker-5-tc2/source
[INFO] started tweaking crates.io crate serde_str_helpers 0.1.2
[INFO] finished tweaking crates.io crate serde_str_helpers 0.1.2
[INFO] tweaked toml for crates.io crate serde_str_helpers 0.1.2 written to /workspace/builds/worker-5-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate serde_str_helpers 0.1.2 on toolchain 4f260f0f20b3133d20cfb50353c0221943af5796
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 11 packages to latest compatible versions
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 2d39220e21780e2d9e24b680d0c989a8c470ab7b1b30624e8f09ceaf978c4155
[INFO] running `Command { std: "docker" "start" "-a" "2d39220e21780e2d9e24b680d0c989a8c470ab7b1b30624e8f09ceaf978c4155", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2d39220e21780e2d9e24b680d0c989a8c470ab7b1b30624e8f09ceaf978c4155", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2d39220e21780e2d9e24b680d0c989a8c470ab7b1b30624e8f09ceaf978c4155", kill_on_drop: false }`
[INFO] [stdout] 2d39220e21780e2d9e24b680d0c989a8c470ab7b1b30624e8f09ceaf978c4155
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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 -Dunmustuse_in_always_ok" "-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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+4f260f0f20b3133d20cfb50353c0221943af5796" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c540a91417f16994c06360dfc0323d1585475990eeb09f9eca9803d2f155978e
[INFO] running `Command { std: "docker" "start" "-a" "c540a91417f16994c06360dfc0323d1585475990eeb09f9eca9803d2f155978e", kill_on_drop: false }`
[INFO] [stderr]     Checking serde_str_helpers v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] error: this type will no longer be must used: Result<CheckDeser, Never>
[INFO] [stdout]    --> src/lib.rs:119:18
[INFO] [stdout]     |
[INFO] [stdout] 119 |         #[derive(serde_derive::Deserialize)]
[INFO] [stdout]     |                  ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: requested on the command line with `-D unmustuse-in-always-ok`
[INFO] [stdout]     = note: this error originates in the derive macro `serde_derive::Deserialize` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: this type will no longer be must used: Result<CheckDeser, Never>
[INFO] [stdout]    --> src/lib.rs:135:81
[INFO] [stdout]     |
[INFO] [stdout] 135 |               fn try_from(value: DeserBorrowStr<'a>) -> Result<Self, Self::Error> {
[INFO] [stdout]     |  _________________________________________________________________________________^
[INFO] [stdout] 136 | |                 if let Cow::Owned(_) = value.into() {
[INFO] [stdout] 137 | |                     panic!("String not borrowed");
[INFO] [stdout] ...   |
[INFO] [stdout] 140 | |                 Ok(CheckDeser)
[INFO] [stdout] 141 | |             }
[INFO] [stdout]     | |_____________^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: this type will no longer be must used: Result<CheckDeser, Never>
[INFO] [stdout]    --> src/lib.rs:140:17
[INFO] [stdout]     |
[INFO] [stdout] 140 |                 Ok(CheckDeser)
[INFO] [stdout]     |                 ^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `serde_str_helpers` (lib test) due to 3 previous errors
[INFO] running `Command { std: "docker" "inspect" "c540a91417f16994c06360dfc0323d1585475990eeb09f9eca9803d2f155978e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c540a91417f16994c06360dfc0323d1585475990eeb09f9eca9803d2f155978e", kill_on_drop: false }`
[INFO] [stdout] c540a91417f16994c06360dfc0323d1585475990eeb09f9eca9803d2f155978e