[INFO] cloning repository https://github.com/vedranvinko/oscar
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/vedranvinko/oscar" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fvedranvinko%2Foscar", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fvedranvinko%2Foscar'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 580f1c03d30f09afd9a3056db7eae2b13b492d46
[INFO] checking vedranvinko/oscar against try#f6e2f78768c57172b99c3e85892f867894dc7e30 for pr-75502
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fvedranvinko%2Foscar" "/workspace/builds/worker-11/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-11/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/vedranvinko/oscar on toolchain f6e2f78768c57172b99c3e85892f867894dc7e30
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+f6e2f78768c57172b99c3e85892f867894dc7e30" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/vedranvinko/oscar
[INFO] finished tweaking git repo https://github.com/vedranvinko/oscar
[INFO] tweaked toml for git repo https://github.com/vedranvinko/oscar written to /workspace/builds/worker-11/source/Cargo.toml
[INFO] crate git repo https://github.com/vedranvinko/oscar already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+f6e2f78768c57172b99c3e85892f867894dc7e30" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+f6e2f78768c57172b99c3e85892f867894dc7e30" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 2ba4a71513a5f4cc299d1e57f3507158f4b44d73bf8a1c0fc43a523e36a07dcd
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "2ba4a71513a5f4cc299d1e57f3507158f4b44d73bf8a1c0fc43a523e36a07dcd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2ba4a71513a5f4cc299d1e57f3507158f4b44d73bf8a1c0fc43a523e36a07dcd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2ba4a71513a5f4cc299d1e57f3507158f4b44d73bf8a1c0fc43a523e36a07dcd", kill_on_drop: false }`
[INFO] [stdout] 2ba4a71513a5f4cc299d1e57f3507158f4b44d73bf8a1c0fc43a523e36a07dcd
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+f6e2f78768c57172b99c3e85892f867894dc7e30" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 398c77263548e71621155dd6617e0fb4de44b160d9b66de668bcb723af019513
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "398c77263548e71621155dd6617e0fb4de44b160d9b66de668bcb723af019513", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.71
[INFO] [stderr]     Checking adler32 v1.1.0
[INFO] [stderr]     Checking gimli v0.21.0
[INFO] [stderr]     Checking rustc-demangle v0.1.16
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]     Checking ansi_term v0.11.0
[INFO] [stderr]     Checking strsim v0.8.0
[INFO] [stderr]    Compiling proc-macro2 v1.0.18
[INFO] [stderr]     Checking miniz_oxide v0.3.7
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling syn v1.0.31
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking clap v2.33.1
[INFO] [stderr]     Checking addr2line v0.12.1
[INFO] [stderr]     Checking backtrace v0.3.49
[INFO] [stderr]     Checking error-chain v0.10.0
[INFO] [stderr]    Compiling serde_derive v1.0.112
[INFO] [stderr]     Checking serde v1.0.112
[INFO] [stderr]     Checking serde-xml-rs v0.3.1
[INFO] [stderr]     Checking oscar v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `serde_xml_rs::from_reader`
[INFO] [stdout]  --> src/main.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use serde_xml_rs::from_reader;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[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 `std::ops::Try`)
[INFO] [stdout]   --> src/main.rs:15:20
[INFO] [stdout]    |
[INFO] [stdout] 14 | / fn read_file(f: String) -> String {
[INFO] [stdout] 15 | |     let mut file = File::open(f)?;
[INFO] [stdout]    | |                    ^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `std::string::String`
[INFO] [stdout] 16 | |     let mut content = String::new();
[INFO] [stdout] 17 | |     file.read_to_string(&mut content)?;
[INFO] [stdout] 18 | |
[INFO] [stdout] 19 | |     content
[INFO] [stdout] 20 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `std::ops::Try` is not implemented for `std::string::String`
[INFO] [stdout]    = note: required by `std::ops::Try::from_error`
[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 `std::ops::Try`)
[INFO] [stdout]   --> src/main.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 14 | / fn read_file(f: String) -> String {
[INFO] [stdout] 15 | |     let mut file = File::open(f)?;
[INFO] [stdout] 16 | |     let mut content = String::new();
[INFO] [stdout] 17 | |     file.read_to_string(&mut content)?;
[INFO] [stdout]    | |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `std::string::String`
[INFO] [stdout] 18 | |
[INFO] [stdout] 19 | |     content
[INFO] [stdout] 20 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `std::ops::Try` is not implemented for `std::string::String`
[INFO] [stdout]    = note: required by `std::ops::Try::from_error`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors; 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 `oscar`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused import: `serde_xml_rs::from_reader`
[INFO] [stdout]  --> src/main.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use serde_xml_rs::from_reader;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[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 `std::ops::Try`)
[INFO] [stdout]   --> src/main.rs:15:20
[INFO] [stdout]    |
[INFO] [stdout] 14 | / fn read_file(f: String) -> String {
[INFO] [stdout] 15 | |     let mut file = File::open(f)?;
[INFO] [stdout]    | |                    ^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `std::string::String`
[INFO] [stdout] 16 | |     let mut content = String::new();
[INFO] [stdout] 17 | |     file.read_to_string(&mut content)?;
[INFO] [stdout] 18 | |
[INFO] [stdout] 19 | |     content
[INFO] [stdout] 20 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `std::ops::Try` is not implemented for `std::string::String`
[INFO] [stdout]    = note: required by `std::ops::Try::from_error`
[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 `std::ops::Try`)
[INFO] [stdout]   --> src/main.rs:17:5
[INFO] [stdout]    |
[INFO] [stdout] 14 | / fn read_file(f: String) -> String {
[INFO] [stdout] 15 | |     let mut file = File::open(f)?;
[INFO] [stdout] 16 | |     let mut content = String::new();
[INFO] [stdout] 17 | |     file.read_to_string(&mut content)?;
[INFO] [stdout]    | |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `std::string::String`
[INFO] [stdout] 18 | |
[INFO] [stdout] 19 | |     content
[INFO] [stdout] 20 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `std::ops::Try` is not implemented for `std::string::String`
[INFO] [stdout]    = note: required by `std::ops::Try::from_error`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "398c77263548e71621155dd6617e0fb4de44b160d9b66de668bcb723af019513", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "398c77263548e71621155dd6617e0fb4de44b160d9b66de668bcb723af019513", kill_on_drop: false }`
[INFO] [stdout] 398c77263548e71621155dd6617e0fb4de44b160d9b66de668bcb723af019513