[INFO] cloning repository https://github.com/tao-yi/rustlang-examples
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/tao-yi/rustlang-examples" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftao-yi%2Frustlang-examples", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftao-yi%2Frustlang-examples'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 0522771bbdbd8ba5c2c1e8e77392d46f32b0440d
[INFO] checking tao-yi/rustlang-examples against try#4949cf2f817beadb9a248d423b6d55d6d2398ffe for pr-142681
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftao-yi%2Frustlang-examples" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/tao-yi/rustlang-examples
[INFO] finished tweaking git repo https://github.com/tao-yi/rustlang-examples
[INFO] tweaked toml for git repo https://github.com/tao-yi/rustlang-examples written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/tao-yi/rustlang-examples on toolchain 4949cf2f817beadb9a248d423b6d55d6d2398ffe
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4949cf2f817beadb9a248d423b6d55d6d2398ffe" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/tao-yi/rustlang-examples already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4949cf2f817beadb9a248d423b6d55d6d2398ffe" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: virtual workspace defaulting to `resolver = "1"` despite one or more workspace members being on edition 2021 which implies `resolver = "2"`
[INFO] [stderr] note: to keep the current resolver, specify `workspace.resolver = "1"` in the workspace root's manifest
[INFO] [stderr] note: to use the edition 2021 resolver, specify `workspace.resolver = "2"` in the workspace root's manifest
[INFO] [stderr] note: for more details see https://doc.rust-lang.org/cargo/reference/resolver.html#resolver-versions
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+4949cf2f817beadb9a248d423b6d55d6d2398ffe" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d3b281e03937e97b777a9d4a6311a47399739e73687bda8646e07d1a10680448
[INFO] running `Command { std: "docker" "start" "-a" "d3b281e03937e97b777a9d4a6311a47399739e73687bda8646e07d1a10680448", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d3b281e03937e97b777a9d4a6311a47399739e73687bda8646e07d1a10680448", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d3b281e03937e97b777a9d4a6311a47399739e73687bda8646e07d1a10680448", kill_on_drop: false }`
[INFO] [stdout] d3b281e03937e97b777a9d4a6311a47399739e73687bda8646e07d1a10680448
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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=forbid" "-e" "RUSTDOCFLAGS=--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+4949cf2f817beadb9a248d423b6d55d6d2398ffe" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b20a5ca93d087b3a933c70a58f2271202faf5588d29d2443df8896d58f4b6e76
[INFO] running `Command { std: "docker" "start" "-a" "b20a5ca93d087b3a933c70a58f2271202faf5588d29d2443df8896d58f4b6e76", kill_on_drop: false }`
[INFO] [stderr] warning: virtual workspace defaulting to `resolver = "1"` despite one or more workspace members being on edition 2021 which implies `resolver = "2"`
[INFO] [stderr] note: to keep the current resolver, specify `workspace.resolver = "1"` in the workspace root's manifest
[INFO] [stderr] note: to use the edition 2021 resolver, specify `workspace.resolver = "2"` in the workspace root's manifest
[INFO] [stderr] note: for more details see https://doc.rust-lang.org/cargo/reference/resolver.html#resolver-versions
[INFO] [stderr]    Compiling libc v0.2.139
[INFO] [stderr]    Compiling proc-macro2 v1.0.49
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]    Compiling unicode-ident v1.0.6
[INFO] [stderr]    Compiling quote v1.0.23
[INFO] [stderr]    Compiling syn v1.0.107
[INFO] [stderr]     Checking ppv-lite86 v0.2.17
[INFO] [stderr]     Checking some_lib v0.1.0 (/opt/rustwide/workdir/some_lib)
[INFO] [stderr]     Checking macro_examples v0.1.0 (/opt/rustwide/workdir/macro_examples)
[INFO] [stderr]     Checking closure_examples v0.1.0 (/opt/rustwide/workdir/closure_examples)
[INFO] [stderr]     Checking rust-and-docker v0.1.0 (/opt/rustwide/workdir/rust-and-docker)
[INFO] [stderr]     Checking threads v0.1.0 (/opt/rustwide/workdir/threads)
[INFO] [stderr]     Checking smart_pointers v0.1.0 (/opt/rustwide/workdir/smart_pointers)
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> closure_examples/src/main.rs:65:9
[INFO] [stdout]    |
[INFO] [stdout] 65 |     let y = vec![1, 2, 3];
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `rc`
[INFO] [stdout]  --> smart_pointers/src/main.rs:1:23
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::{ops::Deref, rc};
[INFO] [stdout]   |                       ^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking some_bin v0.1.0 (/opt/rustwide/workdir/some_bin)
[INFO] [stdout] warning: unused variable: `y`
[INFO] [stdout]   --> closure_examples/src/main.rs:65:9
[INFO] [stdout]    |
[INFO] [stdout] 65 |     let y = vec![1, 2, 3];
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_y`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> smart_pointers/src/rc_demo.rs:28:13
[INFO] [stdout]    |
[INFO] [stdout] 28 |         let b = Cons(3, Rc::clone(&a));
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> smart_pointers/src/rc_demo.rs:30:13
[INFO] [stdout]    |
[INFO] [stdout] 30 |         let c = Cons(4, Rc::clone(&a));
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]   --> smart_pointers/src/rc_demo.rs:13:10
[INFO] [stdout]    |
[INFO] [stdout] 13 |     Cons(i32, Rc<List>),
[INFO] [stdout]    |     ---- ^^^  ^^^^^^^^
[INFO] [stdout]    |     |
[INFO] [stdout]    |     fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 13 -     Cons(i32, Rc<List>),
[INFO] [stdout] 13 +     Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `refcell_demo` is never used
[INFO] [stdout]   --> smart_pointers/src/refcell_demo.rs:13:8
[INFO] [stdout]    |
[INFO] [stdout] 13 | pub fn refcell_demo() {}
[INFO] [stdout]    |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `rc`
[INFO] [stdout]  --> smart_pointers/src/main.rs:1:23
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::{ops::Deref, rc};
[INFO] [stdout]   |                       ^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> smart_pointers/src/rc_demo.rs:28:13
[INFO] [stdout]    |
[INFO] [stdout] 28 |         let b = Cons(3, Rc::clone(&a));
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> smart_pointers/src/rc_demo.rs:30:13
[INFO] [stdout]    |
[INFO] [stdout] 30 |         let c = Cons(4, Rc::clone(&a));
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `multiple_senders` is never used
[INFO] [stdout]   --> threads/src/channel_demo.rs:36:4
[INFO] [stdout]    |
[INFO] [stdout] 36 | fn multiple_senders() {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `demo` is never used
[INFO] [stdout]  --> threads/src/sharing_memory.rs:8:4
[INFO] [stdout]   |
[INFO] [stdout] 8 | fn demo() {
[INFO] [stdout]   |    ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]   --> smart_pointers/src/rc_demo.rs:13:10
[INFO] [stdout]    |
[INFO] [stdout] 13 |     Cons(i32, Rc<List>),
[INFO] [stdout]    |     ---- ^^^  ^^^^^^^^
[INFO] [stdout]    |     |
[INFO] [stdout]    |     fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 13 -     Cons(i32, Rc<List>),
[INFO] [stdout] 13 +     Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `refcell_demo` is never used
[INFO] [stdout]   --> smart_pointers/src/refcell_demo.rs:13:8
[INFO] [stdout]    |
[INFO] [stdout] 13 | pub fn refcell_demo() {}
[INFO] [stdout]    |        ^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0635]: unknown feature `proc_macro_span_shrink`
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/proc-macro2-1.0.49/src/lib.rs:92:30
[INFO] [stdout]    |
[INFO] [stdout] 92 |     feature(proc_macro_span, proc_macro_span_shrink)
[INFO] [stdout]    |                              ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0635`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `proc-macro2` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "b20a5ca93d087b3a933c70a58f2271202faf5588d29d2443df8896d58f4b6e76", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b20a5ca93d087b3a933c70a58f2271202faf5588d29d2443df8896d58f4b6e76", kill_on_drop: false }`
[INFO] [stdout] b20a5ca93d087b3a933c70a58f2271202faf5588d29d2443df8896d58f4b6e76