[INFO] fetching crate fuzzcheck_mutators_derive 0.13.0...
[INFO] testing fuzzcheck_mutators_derive-0.13.0 against beta-2025-09-21 for beta-1.91-3
[INFO] extracting crate fuzzcheck_mutators_derive 0.13.0 into /workspace/builds/worker-3-tc2/source
[INFO] started tweaking crates.io crate fuzzcheck_mutators_derive 0.13.0
[INFO] finished tweaking crates.io crate fuzzcheck_mutators_derive 0.13.0
[INFO] tweaked toml for crates.io crate fuzzcheck_mutators_derive 0.13.0 written to /workspace/builds/worker-3-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate fuzzcheck_mutators_derive 0.13.0 on toolchain beta-2025-09-21
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2025-09-21" "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" "+beta-2025-09-21" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 4 packages to latest compatible versions
[INFO] [stderr]       Adding syn v1.0.109 (available: v2.0.106)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2025-09-21" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2025-09-21" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 60d6be1c1f285f47ed3f4371e2881b7164bcbcf628d0b29702958479a64c9f07
[INFO] running `Command { std: "docker" "start" "-a" "60d6be1c1f285f47ed3f4371e2881b7164bcbcf628d0b29702958479a64c9f07", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "60d6be1c1f285f47ed3f4371e2881b7164bcbcf628d0b29702958479a64c9f07", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "60d6be1c1f285f47ed3f4371e2881b7164bcbcf628d0b29702958479a64c9f07", kill_on_drop: false }`
[INFO] [stdout] 60d6be1c1f285f47ed3f4371e2881b7164bcbcf628d0b29702958479a64c9f07
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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=warn" "-e" "RUSTDOCFLAGS=--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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2025-09-21" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e04dfa91407ce442b8c968545135a981594162e5d40cca614b18427f0e1b19d1
[INFO] running `Command { std: "docker" "start" "-a" "e04dfa91407ce442b8c968545135a981594162e5d40cca614b18427f0e1b19d1", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling fuzzcheck_mutators_derive v0.13.0 (/opt/rustwide/workdir)
[INFO] [stdout] error: let chains are only allowed in Rust 2024 or later
[INFO] [stdout]    --> src/lib.rs:337:8
[INFO] [stdout]     |
[INFO] [stdout] 337 |     if let Some(ident) = attribute.path.get_ident()
[INFO] [stdout]     |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:4:1
[INFO] [stdout]   |
[INFO] [stdout] 4 | #![feature(stmt_expr_attributes)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(let_chains)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `let_chains` has been stable since `1.88.0` and no longer requires an attribute to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around type
[INFO] [stdout]    --> src/lib.rs:240:19
[INFO] [stdout]     |
[INFO] [stdout] 240 |     Mi_j: Box<dyn (Fn(usize, usize) -> Ident)>,
[INFO] [stdout]     |                   ^                         ^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_parens)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 240 -     Mi_j: Box<dyn (Fn(usize, usize) -> Ident)>,
[INFO] [stdout] 240 +     Mi_j: Box<dyn Fn(usize, usize) -> Ident>,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around type
[INFO] [stdout]    --> src/lib.rs:241:17
[INFO] [stdout]     |
[INFO] [stdout] 241 |     Mi: Box<dyn (Fn(usize) -> Ident)>,
[INFO] [stdout]     |                 ^                  ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 241 -     Mi: Box<dyn (Fn(usize) -> Ident)>,
[INFO] [stdout] 241 +     Mi: Box<dyn Fn(usize) -> Ident>,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around type
[INFO] [stdout]    --> src/lib.rs:242:24
[INFO] [stdout]     |
[INFO] [stdout] 242 |     mutator_i: Box<dyn (Fn(usize) -> Ident)>,
[INFO] [stdout]     |                        ^                  ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 242 -     mutator_i: Box<dyn (Fn(usize) -> Ident)>,
[INFO] [stdout] 242 +     mutator_i: Box<dyn Fn(usize) -> Ident>,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around type
[INFO] [stdout]    --> src/lib.rs:248:17
[INFO] [stdout]     |
[INFO] [stdout] 248 |     ti: Box<dyn (Fn(usize) -> Ident)>,
[INFO] [stdout]     |                 ^                  ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 248 -     ti: Box<dyn (Fn(usize) -> Ident)>,
[INFO] [stdout] 248 +     ti: Box<dyn Fn(usize) -> Ident>,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around type
[INFO] [stdout]    --> src/lib.rs:249:23
[INFO] [stdout]     |
[INFO] [stdout] 249 |     ti_value: Box<dyn (Fn(usize) -> Ident)>,
[INFO] [stdout]     |                       ^                  ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 249 -     ti_value: Box<dyn (Fn(usize) -> Ident)>,
[INFO] [stdout] 249 +     ti_value: Box<dyn Fn(usize) -> Ident>,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around type
[INFO] [stdout]    --> src/lib.rs:250:17
[INFO] [stdout]     |
[INFO] [stdout] 250 |     Ti: Box<dyn (Fn(usize) -> Ident)>,
[INFO] [stdout]     |                 ^                  ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 250 -     Ti: Box<dyn (Fn(usize) -> Ident)>,
[INFO] [stdout] 250 +     Ti: Box<dyn Fn(usize) -> Ident>,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around type
[INFO] [stdout]    --> src/lib.rs:251:21
[INFO] [stdout]     |
[INFO] [stdout] 251 |     Tuplei: Box<dyn (Fn(usize) -> TokenStream)>,
[INFO] [stdout]     |                     ^                        ^
[INFO] [stdout]     |
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 251 -     Tuplei: Box<dyn (Fn(usize) -> TokenStream)>,
[INFO] [stdout] 251 +     Tuplei: Box<dyn Fn(usize) -> TokenStream>,
[INFO] [stdout]     |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `let_chains` has been stable since 1.88.0 and no longer requires an attribute to enable
[INFO] [stdout]  --> src/lib.rs:5:12
[INFO] [stdout]   |
[INFO] [stdout] 5 | #![feature(let_chains)]
[INFO] [stdout]   |            ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(stable_features)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `fuzzcheck_mutators_derive` (lib) due to 3 previous errors; 8 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "e04dfa91407ce442b8c968545135a981594162e5d40cca614b18427f0e1b19d1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e04dfa91407ce442b8c968545135a981594162e5d40cca614b18427f0e1b19d1", kill_on_drop: false }`
[INFO] [stdout] e04dfa91407ce442b8c968545135a981594162e5d40cca614b18427f0e1b19d1