[INFO] fetching crate ferris-gc-proc-macro 0.1.2...
[INFO] testing ferris-gc-proc-macro-0.1.2 against try#03a1ea71b075ab964b5278bc6e74cd6c52c36ee0 for pr-74409
[INFO] extracting crate ferris-gc-proc-macro 0.1.2 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate ferris-gc-proc-macro 0.1.2 on toolchain 03a1ea71b075ab964b5278bc6e74cd6c52c36ee0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+03a1ea71b075ab964b5278bc6e74cd6c52c36ee0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate ferris-gc-proc-macro 0.1.2
[INFO] finished tweaking crates.io crate ferris-gc-proc-macro 0.1.2
[INFO] tweaked toml for crates.io crate ferris-gc-proc-macro 0.1.2 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+03a1ea71b075ab964b5278bc6e74cd6c52c36ee0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+03a1ea71b075ab964b5278bc6e74cd6c52c36ee0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:38e1b949b06cde1964af550a6e548bd9b2b2ea170003ae122f8fc0886596cc07" "/opt/rustwide/cargo-home/bin/cargo" "+03a1ea71b075ab964b5278bc6e74cd6c52c36ee0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 93e8dd0e3f9d81aac088b7097eb3b4ae887807ec339347060965c0b9b9bf5ce2
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "93e8dd0e3f9d81aac088b7097eb3b4ae887807ec339347060965c0b9b9bf5ce2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "93e8dd0e3f9d81aac088b7097eb3b4ae887807ec339347060965c0b9b9bf5ce2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "93e8dd0e3f9d81aac088b7097eb3b4ae887807ec339347060965c0b9b9bf5ce2", kill_on_drop: false }`
[INFO] [stdout] 93e8dd0e3f9d81aac088b7097eb3b4ae887807ec339347060965c0b9b9bf5ce2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-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@sha256:38e1b949b06cde1964af550a6e548bd9b2b2ea170003ae122f8fc0886596cc07" "/opt/rustwide/cargo-home/bin/cargo" "+03a1ea71b075ab964b5278bc6e74cd6c52c36ee0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 77dced24bd98806e1f139ec957dab4ffd6dc2b2f8670d6cbb2f3a7c006ecf029
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "77dced24bd98806e1f139ec957dab4ffd6dc2b2f8670d6cbb2f3a7c006ecf029", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.19
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.35
[INFO] [stderr]    Compiling quote v1.0.7
[INFO] [stderr]    Compiling ferris-gc-proc-macro v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused imports: `BorrowMut`, `Borrow`
[INFO] [stdout]  --> src/lib.rs:2:19
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::borrow::{Borrow, BorrowMut};
[INFO] [stdout]   |                   ^^^^^^  ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Type`
[INFO] [stdout]  --> src/lib.rs:4:23
[INFO] [stdout]   |
[INFO] [stdout] 4 | use syn::{ReturnType, Type, Data, Fields};
[INFO] [stdout]   |                       ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `data_enum`
[INFO] [stdout]   --> src/lib.rs:87:20
[INFO] [stdout]    |
[INFO] [stdout] 87 |         Data::Enum(data_enum) => {
[INFO] [stdout]    |                    ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_data_enum`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `data_union`
[INFO] [stdout]   --> src/lib.rs:90:21
[INFO] [stdout]    |
[INFO] [stdout] 90 |         Data::Union(data_union) => {
[INFO] [stdout]    |                     ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_data_union`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `attr_args`
[INFO] [stdout]    --> src/lib.rs:120:9
[INFO] [stdout]     |
[INFO] [stdout] 120 |     let attr_args = syn::parse_macro_input!(attrs as syn::AttributeArgs);
[INFO] [stdout]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_attr_args`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sig`
[INFO] [stdout]    --> src/lib.rs:122:9
[INFO] [stdout]     |
[INFO] [stdout] 122 |     let sig = &input.sig;
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_sig`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `arrow`
[INFO] [stdout]    --> src/lib.rs:137:26
[INFO] [stdout]     |
[INFO] [stdout] 137 |         ReturnType::Type(arrow, box_type) => {
[INFO] [stdout]     |                          ^^^^^ help: if this is intentional, prefix it with an underscore: `_arrow`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 15.55s
[INFO] running `Command { std: "docker" "inspect" "77dced24bd98806e1f139ec957dab4ffd6dc2b2f8670d6cbb2f3a7c006ecf029", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "77dced24bd98806e1f139ec957dab4ffd6dc2b2f8670d6cbb2f3a7c006ecf029", kill_on_drop: false }`
[INFO] [stdout] 77dced24bd98806e1f139ec957dab4ffd6dc2b2f8670d6cbb2f3a7c006ecf029
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-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@sha256:38e1b949b06cde1964af550a6e548bd9b2b2ea170003ae122f8fc0886596cc07" "/opt/rustwide/cargo-home/bin/cargo" "+03a1ea71b075ab964b5278bc6e74cd6c52c36ee0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 28c6bc73a5ee1bcfeb434365a8b616dde093fe132bbaeb14a11b826ec0ca5f43
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "28c6bc73a5ee1bcfeb434365a8b616dde093fe132bbaeb14a11b826ec0ca5f43", kill_on_drop: false }`
[INFO] [stdout] warning: unused imports: `BorrowMut`, `Borrow`
[INFO] [stdout]  --> src/lib.rs:2:19
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::borrow::{Borrow, BorrowMut};
[INFO] [stdout]   |                   ^^^^^^  ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Type`
[INFO] [stdout]  --> src/lib.rs:4:23
[INFO] [stdout]   |
[INFO] [stdout] 4 | use syn::{ReturnType, Type, Data, Fields};
[INFO] [stdout]   |                       ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `data_enum`
[INFO] [stdout]   --> src/lib.rs:87:20
[INFO] [stdout]    |
[INFO] [stdout] 87 |         Data::Enum(data_enum) => {
[INFO] [stdout]    |                    ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_data_enum`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `data_union`
[INFO] [stdout]   --> src/lib.rs:90:21
[INFO] [stdout]    |
[INFO] [stdout] 90 |         Data::Union(data_union) => {
[INFO] [stdout]    |                     ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_data_union`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `attr_args`
[INFO] [stdout]    --> src/lib.rs:120:9
[INFO] [stdout]     |
[INFO] [stdout] 120 |     let attr_args = syn::parse_macro_input!(attrs as syn::AttributeArgs);
[INFO] [stdout]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_attr_args`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sig`
[INFO] [stdout]    --> src/lib.rs:122:9
[INFO] [stdout]     |
[INFO] [stdout] 122 |     let sig = &input.sig;
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_sig`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `arrow`
[INFO] [stdout]    --> src/lib.rs:137:26
[INFO] [stdout]     |
[INFO] [stdout] 137 |         ReturnType::Type(arrow, box_type) => {
[INFO] [stdout]     |                          ^^^^^ help: if this is intentional, prefix it with an underscore: `_arrow`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling ferris-gc-proc-macro v0.1.2 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused imports: `BorrowMut`, `Borrow`
[INFO] [stdout]  --> src/lib.rs:2:19
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::borrow::{Borrow, BorrowMut};
[INFO] [stdout]   |                   ^^^^^^  ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Type`
[INFO] [stdout]  --> src/lib.rs:4:23
[INFO] [stdout]   |
[INFO] [stdout] 4 | use syn::{ReturnType, Type, Data, Fields};
[INFO] [stdout]   |                       ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `data_enum`
[INFO] [stdout]   --> src/lib.rs:87:20
[INFO] [stdout]    |
[INFO] [stdout] 87 |         Data::Enum(data_enum) => {
[INFO] [stdout]    |                    ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_data_enum`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `data_union`
[INFO] [stdout]   --> src/lib.rs:90:21
[INFO] [stdout]    |
[INFO] [stdout] 90 |         Data::Union(data_union) => {
[INFO] [stdout]    |                     ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_data_union`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `attr_args`
[INFO] [stdout]    --> src/lib.rs:120:9
[INFO] [stdout]     |
[INFO] [stdout] 120 |     let attr_args = syn::parse_macro_input!(attrs as syn::AttributeArgs);
[INFO] [stdout]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_attr_args`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `sig`
[INFO] [stdout]    --> src/lib.rs:122:9
[INFO] [stdout]     |
[INFO] [stdout] 122 |     let sig = &input.sig;
[INFO] [stdout]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_sig`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `arrow`
[INFO] [stdout]    --> src/lib.rs:137:26
[INFO] [stdout]     |
[INFO] [stdout] 137 |         ReturnType::Type(arrow, box_type) => {
[INFO] [stdout]     |                          ^^^^^ help: if this is intentional, prefix it with an underscore: `_arrow`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 7 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.41s
[INFO] running `Command { std: "docker" "inspect" "28c6bc73a5ee1bcfeb434365a8b616dde093fe132bbaeb14a11b826ec0ca5f43", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "28c6bc73a5ee1bcfeb434365a8b616dde093fe132bbaeb14a11b826ec0ca5f43", kill_on_drop: false }`
[INFO] [stdout] 28c6bc73a5ee1bcfeb434365a8b616dde093fe132bbaeb14a11b826ec0ca5f43
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-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@sha256:38e1b949b06cde1964af550a6e548bd9b2b2ea170003ae122f8fc0886596cc07" "/opt/rustwide/cargo-home/bin/cargo" "+03a1ea71b075ab964b5278bc6e74cd6c52c36ee0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 35609557f26b31a6baf47499a2ef7176007bc5b1bfe687609ff0aa5a5d05852a
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "35609557f26b31a6baf47499a2ef7176007bc5b1bfe687609ff0aa5a5d05852a", kill_on_drop: false }`
[INFO] [stderr] warning: unused imports: `BorrowMut`, `Borrow`
[INFO] [stderr]  --> src/lib.rs:2:19
[INFO] [stderr]   |
[INFO] [stderr] 2 | use std::borrow::{Borrow, BorrowMut};
[INFO] [stderr]   |                   ^^^^^^  ^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `Type`
[INFO] [stderr]  --> src/lib.rs:4:23
[INFO] [stderr]   |
[INFO] [stderr] 4 | use syn::{ReturnType, Type, Data, Fields};
[INFO] [stderr]   |                       ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `data_enum`
[INFO] [stderr]   --> src/lib.rs:87:20
[INFO] [stderr]    |
[INFO] [stderr] 87 |         Data::Enum(data_enum) => {
[INFO] [stderr]    |                    ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_data_enum`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `data_union`
[INFO] [stderr]   --> src/lib.rs:90:21
[INFO] [stderr]    |
[INFO] [stderr] 90 |         Data::Union(data_union) => {
[INFO] [stderr]    |                     ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_data_union`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `attr_args`
[INFO] [stderr]    --> src/lib.rs:120:9
[INFO] [stderr]     |
[INFO] [stderr] 120 |     let attr_args = syn::parse_macro_input!(attrs as syn::AttributeArgs);
[INFO] [stderr]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_attr_args`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `sig`
[INFO] [stderr]    --> src/lib.rs:122:9
[INFO] [stderr]     |
[INFO] [stderr] 122 |     let sig = &input.sig;
[INFO] [stderr]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_sig`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `arrow`
[INFO] [stderr]    --> src/lib.rs:137:26
[INFO] [stderr]     |
[INFO] [stderr] 137 |         ReturnType::Type(arrow, box_type) => {
[INFO] [stderr]     |                          ^^^^^ help: if this is intentional, prefix it with an underscore: `_arrow`
[INFO] [stderr] 
[INFO] [stderr] warning: 7 warnings emitted
[INFO] [stderr] 
[INFO] [stderr] warning: unused imports: `BorrowMut`, `Borrow`
[INFO] [stderr]  --> src/lib.rs:2:19
[INFO] [stderr]   |
[INFO] [stderr] 2 | use std::borrow::{Borrow, BorrowMut};
[INFO] [stderr]   |                   ^^^^^^  ^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `Type`
[INFO] [stderr]  --> src/lib.rs:4:23
[INFO] [stderr]   |
[INFO] [stderr] 4 | use syn::{ReturnType, Type, Data, Fields};
[INFO] [stderr]   |                       ^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `data_enum`
[INFO] [stderr]   --> src/lib.rs:87:20
[INFO] [stderr]    |
[INFO] [stderr] 87 |         Data::Enum(data_enum) => {
[INFO] [stderr]    |                    ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_data_enum`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `data_union`
[INFO] [stderr]   --> src/lib.rs:90:21
[INFO] [stderr]    |
[INFO] [stderr] 90 |         Data::Union(data_union) => {
[INFO] [stderr]    |                     ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_data_union`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `attr_args`
[INFO] [stderr]    --> src/lib.rs:120:9
[INFO] [stderr]     |
[INFO] [stderr] 120 |     let attr_args = syn::parse_macro_input!(attrs as syn::AttributeArgs);
[INFO] [stderr]     |         ^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_attr_args`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `sig`
[INFO] [stderr]    --> src/lib.rs:122:9
[INFO] [stderr]     |
[INFO] [stderr] 122 |     let sig = &input.sig;
[INFO] [stderr]     |         ^^^ help: if this is intentional, prefix it with an underscore: `_sig`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `arrow`
[INFO] [stderr]    --> src/lib.rs:137:26
[INFO] [stderr]     |
[INFO] [stderr] 137 |         ReturnType::Type(arrow, box_type) => {
[INFO] [stderr]     |                          ^^^^^ help: if this is intentional, prefix it with an underscore: `_arrow`
[INFO] [stderr] 
[INFO] [stderr] warning: 7 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/ferris_gc_proc_macro-8529b1795aa838fe
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests ferris-gc-proc-macro
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "35609557f26b31a6baf47499a2ef7176007bc5b1bfe687609ff0aa5a5d05852a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "35609557f26b31a6baf47499a2ef7176007bc5b1bfe687609ff0aa5a5d05852a", kill_on_drop: false }`
[INFO] [stdout] 35609557f26b31a6baf47499a2ef7176007bc5b1bfe687609ff0aa5a5d05852a