[INFO] fetching crate corundum 0.4.0...
[INFO] checking corundum-0.4.0 against 1.55.0 for beta-1.56-3
[INFO] extracting crate corundum 0.4.0 into /workspace/builds/worker-56/source
[INFO] validating manifest of crates.io crate corundum 0.4.0 on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate corundum 0.4.0
[INFO] finished tweaking crates.io crate corundum 0.4.0
[INFO] tweaked toml for crates.io crate corundum 0.4.0 written to /workspace/builds/worker-56/source/Cargo.toml
[INFO] crate crates.io crate corundum 0.4.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded impl-trait-for-tuples v0.2.1
[INFO] [stderr]   Downloaded crndm_derive v0.1.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-56/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-56/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6b34fcd3a33bde69e48380e312e100746ec6eea36eadfda8a692543c876cc20e
[INFO] running `Command { std: "docker" "start" "-a" "6b34fcd3a33bde69e48380e312e100746ec6eea36eadfda8a692543c876cc20e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6b34fcd3a33bde69e48380e312e100746ec6eea36eadfda8a692543c876cc20e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6b34fcd3a33bde69e48380e312e100746ec6eea36eadfda8a692543c876cc20e", kill_on_drop: false }`
[INFO] [stdout] 6b34fcd3a33bde69e48380e312e100746ec6eea36eadfda8a692543c876cc20e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-56/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-56/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=warn" "-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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 43028ceac11125dc06c2303818f3717743b0659f3fd0506e7bcd1627b594e77e
[INFO] running `Command { std: "docker" "start" "-a" "43028ceac11125dc06c2303818f3717743b0659f3fd0506e7bcd1627b594e77e", kill_on_drop: false }`
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling libc v0.2.94
[INFO] [stderr]    Compiling proc-macro2 v1.0.26
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling getrandom v0.1.16
[INFO] [stderr]    Compiling syn v1.0.72
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]    Compiling memchr v2.4.0
[INFO] [stderr]     Checking ppv-lite86 v0.2.10
[INFO] [stderr]     Checking regex-syntax v0.6.25
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling num-bigint v0.3.2
[INFO] [stderr]    Compiling num-rational v0.3.2
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]     Checking aho-corasick v0.7.18
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]     Checking dirs-sys v0.3.6
[INFO] [stderr]     Checking memmap v0.7.0
[INFO] [stderr]     Checking num_cpus v1.13.0
[INFO] [stderr]     Checking num-complex v0.3.1
[INFO] [stderr]     Checking dirs v2.0.2
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking term v0.6.1
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]     Checking term-painter v0.3.0
[INFO] [stderr]     Checking regex v1.5.4
[INFO] [stderr]     Checking num v0.3.1
[INFO] [stderr]    Compiling crndm_derive v0.1.1
[INFO] [stderr]    Compiling impl-trait-for-tuples v0.2.1
[INFO] [stderr]     Checking corundum v0.4.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:104:1
[INFO] [stdout]     |
[INFO] [stdout] 104 | #![feature(auto_traits)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:105:1
[INFO] [stdout]     |
[INFO] [stdout] 105 | #![feature(untagged_unions)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:106:1
[INFO] [stdout]     |
[INFO] [stdout] 106 | #![feature(const_fn_trait_bound)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:107:1
[INFO] [stdout]     |
[INFO] [stdout] 107 | #![feature(specialization)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:108:1
[INFO] [stdout]     |
[INFO] [stdout] 108 | #![feature(concat_idents)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:109:1
[INFO] [stdout]     |
[INFO] [stdout] 109 | #![feature(llvm_asm)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:110:1
[INFO] [stdout]     |
[INFO] [stdout] 110 | #![feature(core_intrinsics)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:111:1
[INFO] [stdout]     |
[INFO] [stdout] 111 | #![feature(thread_id_value)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:112:1
[INFO] [stdout]     |
[INFO] [stdout] 112 | #![feature(negative_impls)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:113:1
[INFO] [stdout]     |
[INFO] [stdout] 113 | #![feature(backtrace)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:114:1
[INFO] [stdout]     |
[INFO] [stdout] 114 | #![feature(trusted_len)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:115:1
[INFO] [stdout]     |
[INFO] [stdout] 115 | #![feature(exact_size_is_empty)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:116:1
[INFO] [stdout]     |
[INFO] [stdout] 116 | #![feature(alloc_layout_extra)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:117:1
[INFO] [stdout]     |
[INFO] [stdout] 117 | #![feature(dropck_eyepatch)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:118:1
[INFO] [stdout]     |
[INFO] [stdout] 118 | #![feature(trivial_bounds)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:119:1
[INFO] [stdout]     |
[INFO] [stdout] 119 | #![feature(stmt_expr_attributes)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:120:1
[INFO] [stdout]     |
[INFO] [stdout] 120 | #![feature(trait_alias)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:121:1
[INFO] [stdout]     |
[INFO] [stdout] 121 | #![feature(slice_concat_trait)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:122:1
[INFO] [stdout]     |
[INFO] [stdout] 122 | #![feature(slice_partition_dedup)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:123:1
[INFO] [stdout]     |
[INFO] [stdout] 123 | #![feature(const_generics)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:124:1
[INFO] [stdout]     |
[INFO] [stdout] 124 | #![feature(type_name_of_val)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:125:1
[INFO] [stdout]     |
[INFO] [stdout] 125 | #![feature(pattern)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:126:1
[INFO] [stdout]     |
[INFO] [stdout] 126 | #![feature(try_reserve)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:127:1
[INFO] [stdout]     |
[INFO] [stdout] 127 | #![feature(str_internals)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:128:1
[INFO] [stdout]     |
[INFO] [stdout] 128 | #![feature(toowned_clone_into)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:129:1
[INFO] [stdout]     |
[INFO] [stdout] 129 | #![feature(fn_traits)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:130:1
[INFO] [stdout]     |
[INFO] [stdout] 130 | #![feature(unboxed_closures)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:131:1
[INFO] [stdout]     |
[INFO] [stdout] 131 | #![feature(let_chains)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:132:1
[INFO] [stdout]     |
[INFO] [stdout] 132 | #![feature(c_variadic)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:133:1
[INFO] [stdout]     |
[INFO] [stdout] 133 | #![feature(rustc_attrs)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:134:1
[INFO] [stdout]     |
[INFO] [stdout] 134 | #![feature(allocator_api)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:135:1
[INFO] [stdout]     |
[INFO] [stdout] 135 | #![feature(associated_type_bounds)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:136:1
[INFO] [stdout]     |
[INFO] [stdout] 136 | #![feature(async_stream)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:104:1
[INFO] [stdout]     |
[INFO] [stdout] 104 | #![feature(auto_traits)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:105:1
[INFO] [stdout]     |
[INFO] [stdout] 105 | #![feature(untagged_unions)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:106:1
[INFO] [stdout]     |
[INFO] [stdout] 106 | #![feature(const_fn_trait_bound)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:107:1
[INFO] [stdout]     |
[INFO] [stdout] 107 | #![feature(specialization)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:108:1
[INFO] [stdout]     |
[INFO] [stdout] 108 | #![feature(concat_idents)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:109:1
[INFO] [stdout]     |
[INFO] [stdout] 109 | #![feature(llvm_asm)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:110:1
[INFO] [stdout]     |
[INFO] [stdout] 110 | #![feature(core_intrinsics)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:111:1
[INFO] [stdout]     |
[INFO] [stdout] 111 | #![feature(thread_id_value)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:112:1
[INFO] [stdout]     |
[INFO] [stdout] 112 | #![feature(negative_impls)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:113:1
[INFO] [stdout]     |
[INFO] [stdout] 113 | #![feature(backtrace)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:114:1
[INFO] [stdout]     |
[INFO] [stdout] 114 | #![feature(trusted_len)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:115:1
[INFO] [stdout]     |
[INFO] [stdout] 115 | #![feature(exact_size_is_empty)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:116:1
[INFO] [stdout]     |
[INFO] [stdout] 116 | #![feature(alloc_layout_extra)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:117:1
[INFO] [stdout]     |
[INFO] [stdout] 117 | #![feature(dropck_eyepatch)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:118:1
[INFO] [stdout]     |
[INFO] [stdout] 118 | #![feature(trivial_bounds)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:119:1
[INFO] [stdout]     |
[INFO] [stdout] 119 | #![feature(stmt_expr_attributes)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:120:1
[INFO] [stdout]     |
[INFO] [stdout] 120 | #![feature(trait_alias)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:121:1
[INFO] [stdout]     |
[INFO] [stdout] 121 | #![feature(slice_concat_trait)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:122:1
[INFO] [stdout]     |
[INFO] [stdout] 122 | #![feature(slice_partition_dedup)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:123:1
[INFO] [stdout]     |
[INFO] [stdout] 123 | #![feature(const_generics)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:124:1
[INFO] [stdout]     |
[INFO] [stdout] 124 | #![feature(type_name_of_val)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:125:1
[INFO] [stdout]     |
[INFO] [stdout] 125 | #![feature(pattern)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:126:1
[INFO] [stdout]     |
[INFO] [stdout] 126 | #![feature(try_reserve)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:127:1
[INFO] [stdout]     |
[INFO] [stdout] 127 | #![feature(str_internals)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:128:1
[INFO] [stdout]     |
[INFO] [stdout] 128 | #![feature(toowned_clone_into)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:129:1
[INFO] [stdout]     |
[INFO] [stdout] 129 | #![feature(fn_traits)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:130:1
[INFO] [stdout]     |
[INFO] [stdout] 130 | #![feature(unboxed_closures)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:131:1
[INFO] [stdout]     |
[INFO] [stdout] 131 | #![feature(let_chains)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:132:1
[INFO] [stdout]     |
[INFO] [stdout] 132 | #![feature(c_variadic)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:133:1
[INFO] [stdout]     |
[INFO] [stdout] 133 | #![feature(rustc_attrs)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:134:1
[INFO] [stdout]     |
[INFO] [stdout] 134 | #![feature(allocator_api)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:135:1
[INFO] [stdout]     |
[INFO] [stdout] 135 | #![feature(associated_type_bounds)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> src/lib.rs:136:1
[INFO] [stdout]     |
[INFO] [stdout] 136 | #![feature(async_stream)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 33 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `corundum` due to 34 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error: aborting due to 33 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "43028ceac11125dc06c2303818f3717743b0659f3fd0506e7bcd1627b594e77e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "43028ceac11125dc06c2303818f3717743b0659f3fd0506e7bcd1627b594e77e", kill_on_drop: false }`
[INFO] [stdout] 43028ceac11125dc06c2303818f3717743b0659f3fd0506e7bcd1627b594e77e
