[INFO] fetching crate libextra 0.1.0...
[INFO] checking libextra-0.1.0 against master#507271bc119683008ec719ecee48814e8ac86c65 for pr-146440
[INFO] extracting crate libextra 0.1.0 into /workspace/builds/worker-6-tc1/source
[INFO] started tweaking crates.io crate libextra 0.1.0
[INFO] finished tweaking crates.io crate libextra 0.1.0
[INFO] tweaked toml for crates.io crate libextra 0.1.0 written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate libextra 0.1.0 on toolchain 507271bc119683008ec719ecee48814e8ac86c65
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+507271bc119683008ec719ecee48814e8ac86c65" "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" "+507271bc119683008ec719ecee48814e8ac86c65" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+507271bc119683008ec719ecee48814e8ac86c65" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+507271bc119683008ec719ecee48814e8ac86c65" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 61c5cf4fed36fd1b875fe78b80d6903a7450cf9289d28df8363c50ad3f7b8b8b
[INFO] running `Command { std: "docker" "start" "-a" "61c5cf4fed36fd1b875fe78b80d6903a7450cf9289d28df8363c50ad3f7b8b8b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "61c5cf4fed36fd1b875fe78b80d6903a7450cf9289d28df8363c50ad3f7b8b8b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "61c5cf4fed36fd1b875fe78b80d6903a7450cf9289d28df8363c50ad3f7b8b8b", kill_on_drop: false }`
[INFO] [stdout] 61c5cf4fed36fd1b875fe78b80d6903a7450cf9289d28df8363c50ad3f7b8b8b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+507271bc119683008ec719ecee48814e8ac86c65" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 85267e92ba023c7fdaf676cc021a07b70f4ed4417caf93038e07c2845c162347
[INFO] running `Command { std: "docker" "start" "-a" "85267e92ba023c7fdaf676cc021a07b70f4ed4417caf93038e07c2845c162347", kill_on_drop: false }`
[INFO] [stderr]     Checking libextra v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused imports: `Enumerate` and `FilterMap`
[INFO] [stdout]  --> src/map.rs:3:17
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::iter::{Enumerate, FilterMap};
[INFO] [stdout]   |                 ^^^^^^^^^  ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused macro definition: `iterator`
[INFO] [stdout]   --> src/map.rs:39:14
[INFO] [stdout]    |
[INFO] [stdout] 39 | macro_rules! iterator {
[INFO] [stdout]    |              ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_macros)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/bitv.rs:7:47
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn iterate_bits(base: usize, bits: usize, f: &Fn(usize) -> bool) -> bool {
[INFO] [stdout]   |                                               ^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]   = note: `#[warn(bare_trait_objects)]` (part of `#[warn(rust_2021_compatibility)]`) on by default
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn iterate_bits(base: usize, bits: usize, f: &dyn Fn(usize) -> bool) -> bool {
[INFO] [stdout]   |                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/map.rs:36:11
[INFO] [stdout]    |
[INFO] [stdout] 36 |     iter: Iterator<Item=Option<T>> + 'a,
[INFO] [stdout]    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 36 |     iter: dyn Iterator<Item=Option<T>> + 'a,
[INFO] [stdout]    |           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/vec.rs:5:24
[INFO] [stdout]   |
[INFO] [stdout] 5 |     fn count(&self,f: &Fn(&T) -> bool) -> usize;
[INFO] [stdout]   |                        ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 5 |     fn count(&self,f: &dyn Fn(&T) -> bool) -> usize;
[INFO] [stdout]   |                        +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Enumerate` and `FilterMap`
[INFO] [stdout]  --> src/map.rs:3:17
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::iter::{Enumerate, FilterMap};
[INFO] [stdout]   |                 ^^^^^^^^^  ^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused macro definition: `iterator`
[INFO] [stdout]   --> src/map.rs:39:14
[INFO] [stdout]    |
[INFO] [stdout] 39 | macro_rules! iterator {
[INFO] [stdout]    |              ^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_macros)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/vec.rs:17:24
[INFO] [stdout]    |
[INFO] [stdout] 17 |     fn count(&self,f: &Fn(&T) -> bool) -> usize {
[INFO] [stdout]    |                        ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 17 |     fn count(&self,f: &dyn Fn(&T) -> bool) -> usize {
[INFO] [stdout]    |                        +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/bitv.rs:44:63
[INFO] [stdout]    |
[INFO] [stdout] 44 |     pub fn process(&mut self, b: &BigBitv, nbits: usize, op: &Fn(usize, usize) -> usize) -> bool {
[INFO] [stdout]    |                                                               ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 44 |     pub fn process(&mut self, b: &BigBitv, nbits: usize, op: &dyn Fn(usize, usize) -> usize) -> bool {
[INFO] [stdout]    |                                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/bitv.rs:216:53
[INFO] [stdout]     |
[INFO] [stdout] 216 |     pub fn other_op(&mut self, other: &BitvSet, f: &Fn(usize, usize) -> usize) {
[INFO] [stdout]     |                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]     |
[INFO] [stdout] 216 |     pub fn other_op(&mut self, other: &BitvSet, f: &dyn Fn(usize, usize) -> usize) {
[INFO] [stdout]     |                                                     +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/bitv.rs:7:47
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn iterate_bits(base: usize, bits: usize, f: &Fn(usize) -> bool) -> bool {
[INFO] [stdout]   |                                               ^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]   = note: `#[warn(bare_trait_objects)]` (part of `#[warn(rust_2021_compatibility)]`) on by default
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn iterate_bits(base: usize, bits: usize, f: &dyn Fn(usize) -> bool) -> bool {
[INFO] [stdout]   |                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/map.rs:36:11
[INFO] [stdout]    |
[INFO] [stdout] 36 |     iter: Iterator<Item=Option<T>> + 'a,
[INFO] [stdout]    |           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 36 |     iter: dyn Iterator<Item=Option<T>> + 'a,
[INFO] [stdout]    |           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/vec.rs:5:24
[INFO] [stdout]   |
[INFO] [stdout] 5 |     fn count(&self,f: &Fn(&T) -> bool) -> usize;
[INFO] [stdout]   |                        ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 5 |     fn count(&self,f: &dyn Fn(&T) -> bool) -> usize;
[INFO] [stdout]   |                        +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/vec.rs:17:24
[INFO] [stdout]    |
[INFO] [stdout] 17 |     fn count(&self,f: &Fn(&T) -> bool) -> usize {
[INFO] [stdout]    |                        ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 17 |     fn count(&self,f: &dyn Fn(&T) -> bool) -> usize {
[INFO] [stdout]    |                        +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/bitv.rs:44:63
[INFO] [stdout]    |
[INFO] [stdout] 44 |     pub fn process(&mut self, b: &BigBitv, nbits: usize, op: &Fn(usize, usize) -> usize) -> bool {
[INFO] [stdout]    |                                                               ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 44 |     pub fn process(&mut self, b: &BigBitv, nbits: usize, op: &dyn Fn(usize, usize) -> usize) -> bool {
[INFO] [stdout]    |                                                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `other`
[INFO] [stdout]    --> src/bitv.rs:179:30
[INFO] [stdout]     |
[INFO] [stdout] 179 |     pub fn difference(&self, other: &BitvSet, f: &fn(&usize) -> bool) -> bool {
[INFO] [stdout]     |                              ^^^^^ help: if this is intentional, prefix it with an underscore: `_other`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/bitv.rs:216:53
[INFO] [stdout]     |
[INFO] [stdout] 216 |     pub fn other_op(&mut self, other: &BitvSet, f: &Fn(usize, usize) -> usize) {
[INFO] [stdout]     |                                                     ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]     |
[INFO] [stdout] 216 |     pub fn other_op(&mut self, other: &BitvSet, f: &dyn Fn(usize, usize) -> usize) {
[INFO] [stdout]     |                                                     +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]    --> src/bitv.rs:179:47
[INFO] [stdout]     |
[INFO] [stdout] 179 |     pub fn difference(&self, other: &BitvSet, f: &fn(&usize) -> bool) -> bool {
[INFO] [stdout]     |                                               ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `iterate_bits` is never used
[INFO] [stdout]  --> src/bitv.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn iterate_bits(base: usize, bits: usize, f: &Fn(usize) -> bool) -> bool {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Op` is never used
[INFO] [stdout]    --> src/bitv.rs:121:6
[INFO] [stdout]     |
[INFO] [stdout] 121 | enum Op {
[INFO] [stdout]     |      ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `front`, `back`, and `iter` are never read
[INFO] [stdout]   --> src/map.rs:34:5
[INFO] [stdout]    |
[INFO] [stdout] 33 | pub struct SmallIntMapIterator<'a,T> {
[INFO] [stdout]    |            ------------------- fields in this struct
[INFO] [stdout] 34 |     front: usize,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 35 |     back: usize,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 36 |     iter: Iterator<Item=Option<T>> + 'a,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's named elsewhere is confusing
[INFO] [stdout]    --> src/bitv.rs:205:34
[INFO] [stdout]     |
[INFO] [stdout] 205 |     pub fn iter<'a>(&'a self) -> BitvSetIterator {
[INFO] [stdout]     |                      --          ^^^^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      the lifetime is named here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]     = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: consistently use `'a`
[INFO] [stdout]     |
[INFO] [stdout] 205 |     pub fn iter<'a>(&'a self) -> BitvSetIterator<'a> {
[INFO] [stdout]     |                                                 ++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `other`
[INFO] [stdout]    --> src/bitv.rs:179:30
[INFO] [stdout]     |
[INFO] [stdout] 179 |     pub fn difference(&self, other: &BitvSet, f: &fn(&usize) -> bool) -> bool {
[INFO] [stdout]     |                              ^^^^^ help: if this is intentional, prefix it with an underscore: `_other`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `f`
[INFO] [stdout]    --> src/bitv.rs:179:47
[INFO] [stdout]     |
[INFO] [stdout] 179 |     pub fn difference(&self, other: &BitvSet, f: &fn(&usize) -> bool) -> bool {
[INFO] [stdout]     |                                               ^ help: if this is intentional, prefix it with an underscore: `_f`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `iterate_bits` is never used
[INFO] [stdout]  --> src/bitv.rs:7:4
[INFO] [stdout]   |
[INFO] [stdout] 7 | fn iterate_bits(base: usize, bits: usize, f: &Fn(usize) -> bool) -> bool {
[INFO] [stdout]   |    ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: enum `Op` is never used
[INFO] [stdout]    --> src/bitv.rs:121:6
[INFO] [stdout]     |
[INFO] [stdout] 121 | enum Op {
[INFO] [stdout]     |      ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `front`, `back`, and `iter` are never read
[INFO] [stdout]   --> src/map.rs:34:5
[INFO] [stdout]    |
[INFO] [stdout] 33 | pub struct SmallIntMapIterator<'a,T> {
[INFO] [stdout]    |            ------------------- fields in this struct
[INFO] [stdout] 34 |     front: usize,
[INFO] [stdout]    |     ^^^^^
[INFO] [stdout] 35 |     back: usize,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 36 |     iter: Iterator<Item=Option<T>> + 'a,
[INFO] [stdout]    |     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: hiding a lifetime that's named elsewhere is confusing
[INFO] [stdout]    --> src/bitv.rs:205:34
[INFO] [stdout]     |
[INFO] [stdout] 205 |     pub fn iter<'a>(&'a self) -> BitvSetIterator {
[INFO] [stdout]     |                      --          ^^^^^^^^^^^^^^^ the same lifetime is hidden here
[INFO] [stdout]     |                      |
[INFO] [stdout]     |                      the lifetime is named here
[INFO] [stdout]     |
[INFO] [stdout]     = help: the same lifetime is referred to in inconsistent ways, making the signature confusing
[INFO] [stdout]     = note: `#[warn(mismatched_lifetime_syntaxes)]` on by default
[INFO] [stdout] help: consistently use `'a`
[INFO] [stdout]     |
[INFO] [stdout] 205 |     pub fn iter<'a>(&'a self) -> BitvSetIterator<'a> {
[INFO] [stdout]     |                                                 ++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.42s
[INFO] running `Command { std: "docker" "inspect" "85267e92ba023c7fdaf676cc021a07b70f4ed4417caf93038e07c2845c162347", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "85267e92ba023c7fdaf676cc021a07b70f4ed4417caf93038e07c2845c162347", kill_on_drop: false }`
[INFO] [stdout] 85267e92ba023c7fdaf676cc021a07b70f4ed4417caf93038e07c2845c162347
