[INFO] updating cached repository Nandem/Rust_learning
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/Nandem/Rust_learning
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/Nandem/Rust_learning" "work/ex/beta-1.38-1/sources/1.37.0/gh/Nandem/Rust_learning"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/Nandem/Rust_learning'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/Nandem/Rust_learning" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Nandem/Rust_learning"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Nandem/Rust_learning'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] f6ba2518afb7cacb51835855bbd260bf98a628b1
[INFO] sha for GitHub repo Nandem/Rust_learning: f6ba2518afb7cacb51835855bbd260bf98a628b1
[INFO] validating manifest of Nandem/Rust_learning on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of Nandem/Rust_learning on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing Nandem/Rust_learning
[INFO] finished frobbing Nandem/Rust_learning
[INFO] frobbed toml for Nandem/Rust_learning written to work/ex/beta-1.38-1/sources/1.37.0/gh/Nandem/Rust_learning/Cargo.toml
[INFO] started frobbing Nandem/Rust_learning
[INFO] finished frobbing Nandem/Rust_learning
[INFO] frobbed toml for Nandem/Rust_learning written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/Nandem/Rust_learning/Cargo.toml
[INFO] crate Nandem/Rust_learning already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing Nandem/Rust_learning against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-6/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/gh/Nandem/Rust_learning:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] b8d067511e3e49c7760acaaa368a0fb765fc8e2c93d9d438178043485d0070ba
[INFO] running `"docker" "start" "-a" "b8d067511e3e49c7760acaaa368a0fb765fc8e2c93d9d438178043485d0070ba"`
[INFO] [stderr]    Compiling learning v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] error[E0433]: failed to resolve: use of undeclared type or module `io`
[INFO] [stderr]   --> src/errors/error1.rs:39:49
[INFO] [stderr]    |
[INFO] [stderr] 39 | fn read_username_from_file1() -> Result<String, io::Error> {
[INFO] [stderr]    |                                                 ^^ use of undeclared type or module `io`
[INFO] [stderr] 
[INFO] [stderr] error[E0433]: failed to resolve: use of undeclared type or module `io`
[INFO] [stderr]   --> src/errors/error1.rs:55:49
[INFO] [stderr]    |
[INFO] [stderr] 55 | fn read_username_from_file2() -> Result<String, io::Error> {
[INFO] [stderr]    |                                                 ^^ use of undeclared type or module `io`
[INFO] [stderr] 
[INFO] [stderr] error[E0433]: failed to resolve: use of undeclared type or module `io`
[INFO] [stderr]   --> src/errors/error1.rs:62:49
[INFO] [stderr]    |
[INFO] [stderr] 62 | fn read_username_from_file3() -> Result<String, io::Error> {
[INFO] [stderr]    |                                                 ^^ use of undeclared type or module `io`
[INFO] [stderr] 
[INFO] [stderr] error[E0599]: no method named `read_to_string` found for type `std::fs::File` in the current scope
[INFO] [stderr]   --> src/errors/error1.rs:49:13
[INFO] [stderr]    |
[INFO] [stderr] 49 |     match f.read_to_string(&mut s) {
[INFO] [stderr]    |             ^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = help: items from traits can only be used if the trait is in scope
[INFO] [stderr]    = note: the following trait is implemented but not in scope, perhaps add a `use` for it:
[INFO] [stderr]            `use std::io::Read;`
[INFO] [stderr] 
[INFO] [stderr] error[E0599]: no method named `read_to_string` found for type `std::fs::File` in the current scope
[INFO] [stderr]   --> src/errors/error1.rs:58:7
[INFO] [stderr]    |
[INFO] [stderr] 58 |     f.read_to_string(&mut s)?;
[INFO] [stderr]    |       ^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = help: items from traits can only be used if the trait is in scope
[INFO] [stderr]    = note: the following trait is implemented but not in scope, perhaps add a `use` for it:
[INFO] [stderr]            `use std::io::Read;`
[INFO] [stderr] 
[INFO] [stderr] error[E0599]: no method named `read_to_string` found for type `std::fs::File` in the current scope
[INFO] [stderr]   --> src/errors/error1.rs:65:30
[INFO] [stderr]    |
[INFO] [stderr] 65 |     File::open("hello.txt")?.read_to_string(&mut s)?;
[INFO] [stderr]    |                              ^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = help: items from traits can only be used if the trait is in scope
[INFO] [stderr]    = note: the following trait is implemented but not in scope, perhaps add a `use` for it:
[INFO] [stderr]            `use std::io::Read;`
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 6 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0433, E0599.
[INFO] [stderr] For more information about an error, try `rustc --explain E0433`.
[INFO] [stderr] error: Could not compile `learning`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "b8d067511e3e49c7760acaaa368a0fb765fc8e2c93d9d438178043485d0070ba"`
[INFO] running `"docker" "rm" "-f" "b8d067511e3e49c7760acaaa368a0fb765fc8e2c93d9d438178043485d0070ba"`
[INFO] [stdout] b8d067511e3e49c7760acaaa368a0fb765fc8e2c93d9d438178043485d0070ba