[INFO] updating cached repository https://github.com/mickvangelderen/rust-os-experiment
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/big/crater/work/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 25bfcd39a66ea1b8154451a88ba869424547e58d
[INFO] testing mickvangelderen/rust-os-experiment against 1.38.0 for beta-1.39-1
[INFO] running `"git" "clone" "work/cache/git-repos/https%3A%2F%2Fgithub.com%2Fmickvangelderen%2Frust-os-experiment" "work/builds/worker-0/source"`
[INFO] [stderr] Cloning into 'work/builds/worker-0/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/mickvangelderen/rust-os-experiment on toolchain 1.38.0
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/mickvangelderen/rust-os-experiment
[INFO] finished tweaking git repo https://github.com/mickvangelderen/rust-os-experiment
[INFO] tweaked toml for git repo https://github.com/mickvangelderen/rust-os-experiment written to work/builds/worker-0/source/Cargo.toml
[INFO] crate git repo https://github.com/mickvangelderen/rust-os-experiment already has a lockfile, it will not be regenerated
[INFO] running `"/big/crater/work/cargo-home/bin/cargo" "+1.38.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/big/crater/work/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/big/crater/work/builds/worker-0/source:/opt/rustwide/workdir:ro,Z" "-v" "/big/crater/work/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/big/crater/work/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+1.38.0" "build" "--frozen"`
[INFO] [stdout] 723cdb7ae052c7d1294250cd65c06aec92ea88358f7a04b86e509cfbfc6ee6e2
[INFO] running `"docker" "start" "-a" "723cdb7ae052c7d1294250cd65c06aec92ea88358f7a04b86e509cfbfc6ee6e2"`
[INFO] [stderr] warning: unused manifest key: profile.panic
[INFO] [stderr]    Compiling rlibc v1.0.0
[INFO] [stderr]    Compiling rust-os-experiment v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(lang_items)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:2:1
[INFO] [stderr]   |
[INFO] [stderr] 2 | #![feature(unique)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:3:1
[INFO] [stderr]   |
[INFO] [stderr] 3 | #![feature(const_fn)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `vga_buffer::ColorCode`
[INFO] [stderr]   --> src/lib.rs:12:7
[INFO] [stderr]    |
[INFO] [stderr] 12 |   use vga_buffer::ColorCode;
[INFO] [stderr]    |       ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `vga_buffer::Color`
[INFO] [stderr]   --> src/lib.rs:13:7
[INFO] [stderr]    |
[INFO] [stderr] 13 |   use vga_buffer::Color;
[INFO] [stderr]    |       ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0522]: definition of an unknown language item: `panic_fmt`
[INFO] [stderr]   --> src/lib.rs:43:1
[INFO] [stderr]    |
[INFO] [stderr] 43 | #[lang = "panic_fmt"]
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^ definition of unknown language item `panic_fmt`
[INFO] [stderr] 
[INFO] [stderr] error: `#[panic_handler]` function required, but not found
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: use of unstable library feature 'ptr_internals': use `NonNull` instead and consider `PhantomData<T>` (if you also use `#[may_dangle]`), `Send`, and/or `Sync`
[INFO] [stderr]   --> src/lib.rs:17:14
[INFO] [stderr]    |
[INFO] [stderr] 17 |     unsafe { Unique::new(0xb8000 as *mut _) }
[INFO] [stderr]    |              ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: use of unstable library feature 'ptr_internals': use `NonNull` instead and consider `PhantomData<T>` (if you also use `#[may_dangle]`), `Send`, and/or `Sync`
[INFO] [stderr]   --> src/lib.rs:14:7
[INFO] [stderr]    |
[INFO] [stderr] 14 |   use core::ptr::Unique;
[INFO] [stderr]    |       ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: use of unstable library feature 'ptr_internals': use `NonNull` instead and consider `PhantomData<T>` (if you also use `#[may_dangle]`), `Send`, and/or `Sync`
[INFO] [stderr]  --> src/vga_buffer.rs:1:5
[INFO] [stderr]   |
[INFO] [stderr] 1 | use core::ptr::Unique;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: use of unstable library feature 'ptr_internals': use `NonNull` instead and consider `PhantomData<T>` (if you also use `#[may_dangle]`), `Send`, and/or `Sync`
[INFO] [stderr]   --> src/vga_buffer.rs:50:11
[INFO] [stderr]    |
[INFO] [stderr] 50 |   buffer: Unique<Buffer>,
[INFO] [stderr]    |           ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: use of unstable library feature 'ptr_internals': use `NonNull` instead and consider `PhantomData<T>` (if you also use `#[may_dangle]`), `Send`, and/or `Sync`
[INFO] [stderr]   --> src/vga_buffer.rs:54:22
[INFO] [stderr]    |
[INFO] [stderr] 54 |   pub fn new(buffer: Unique<Buffer>) -> Writer {
[INFO] [stderr]    |                      ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: use of unstable library feature 'ptr_internals'
[INFO] [stderr]   --> src/lib.rs:17:14
[INFO] [stderr]    |
[INFO] [stderr] 17 |     unsafe { Unique::new(0xb8000 as *mut _) }
[INFO] [stderr]    |              ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0308]: mismatched types
[INFO] [stderr]   --> src/lib.rs:17:14
[INFO] [stderr]    |
[INFO] [stderr] 17 |     unsafe { Unique::new(0xb8000 as *mut _) }
[INFO] [stderr]    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected struct `core::ptr::Unique`, found enum `core::option::Option`
[INFO] [stderr]    |
[INFO] [stderr]    = note: expected type `core::ptr::Unique<vga_buffer::Buffer>`
[INFO] [stderr]               found type `core::option::Option<core::ptr::Unique<_>>`
[INFO] [stderr] 
[INFO] [stderr] error[E0599]: no method named `get_mut` found for type `core::ptr::Unique<vga_buffer::Buffer>` in the current scope
[INFO] [stderr]   --> src/vga_buffer.rs:84:19
[INFO] [stderr]    |
[INFO] [stderr] 84 |       self.buffer.get_mut()
[INFO] [stderr]    |                   ^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 13 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0308, E0522, E0554, E0599, E0658.
[INFO] [stderr] For more information about an error, try `rustc --explain E0308`.
[INFO] [stderr] error: Could not compile `rust-os-experiment`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "723cdb7ae052c7d1294250cd65c06aec92ea88358f7a04b86e509cfbfc6ee6e2"`
[INFO] running `"docker" "rm" "-f" "723cdb7ae052c7d1294250cd65c06aec92ea88358f7a04b86e509cfbfc6ee6e2"`
[INFO] [stdout] 723cdb7ae052c7d1294250cd65c06aec92ea88358f7a04b86e509cfbfc6ee6e2