[INFO] updating cached repository https://github.com/dhoepelman/rust-pong
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] c137445cb4b13ef72b217eb3bb5075ee9e1d1ecc
[INFO] checking dhoepelman/rust-pong against master#bf1f2eedda4fa02b7c9347dd849ed73ddd43dedc for pr-70917
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdhoepelman%2Frust-pong" "/workspace/builds/worker-1/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/dhoepelman/rust-pong on toolchain bf1f2eedda4fa02b7c9347dd849ed73ddd43dedc
[INFO] running `"/workspace/cargo-home/bin/cargo" "+bf1f2eedda4fa02b7c9347dd849ed73ddd43dedc" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/dhoepelman/rust-pong
[INFO] finished tweaking git repo https://github.com/dhoepelman/rust-pong
[INFO] tweaked toml for git repo https://github.com/dhoepelman/rust-pong written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/dhoepelman/rust-pong already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+bf1f2eedda4fa02b7c9347dd849ed73ddd43dedc" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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" "/opt/rustwide/cargo-home/bin/cargo" "+bf1f2eedda4fa02b7c9347dd849ed73ddd43dedc" "check" "--frozen" "--all" "--all-targets"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 3251ec01a4f2aac27ce2660d20f6dc8997f74f339461f5181da1c6c7c24441be
[INFO] running `"docker" "start" "-a" "3251ec01a4f2aac27ce2660d20f6dc8997f74f339461f5181da1c6c7c24441be"`
[INFO] [stderr]    Compiling gmp-mpfr-sys v1.1.10
[INFO] [stderr]    Compiling rug v0.6.0
[INFO] [stderr]     Checking pong v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused import: `std::io`
[INFO] [stderr]  --> src/main.rs:3:5
[INFO] [stderr]   |
[INFO] [stderr] 3 | use std::io;
[INFO] [stderr]   |     ^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `rand::Rng`
[INFO] [stderr]  --> src/main.rs:4:5
[INFO] [stderr]   |
[INFO] [stderr] 4 | use rand::Rng;
[INFO] [stderr]   |     ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::cmp::Ordering`
[INFO] [stderr]  --> src/main.rs:5:5
[INFO] [stderr]   |
[INFO] [stderr] 5 | use std::cmp::Ordering;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `Assign`
[INFO] [stderr]  --> src/main.rs:6:11
[INFO] [stderr]   |
[INFO] [stderr] 6 | use rug::{Assign, Integer};
[INFO] [stderr]   |           ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stderr]   --> src/main.rs:57:22
[INFO] [stderr]    |
[INFO] [stderr] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stderr]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stderr] 51 |     match cache.get(n) {
[INFO] [stderr]    |           ----- immutable borrow occurs here
[INFO] [stderr] 52 |         Some(n) => n,
[INFO] [stderr]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stderr] ...
[INFO] [stderr] 57 |                 m => fib(m-2, cache).clone() + fib(m - 1, cache).clone()
[INFO] [stderr]    |                      ^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stderr] 
[INFO] [stderr] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stderr]   --> src/main.rs:57:48
[INFO] [stderr]    |
[INFO] [stderr] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stderr]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stderr] 51 |     match cache.get(n) {
[INFO] [stderr]    |           ----- immutable borrow occurs here
[INFO] [stderr] 52 |         Some(n) => n,
[INFO] [stderr]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stderr] ...
[INFO] [stderr] 57 |                 m => fib(m-2, cache).clone() + fib(m - 1, cache).clone()
[INFO] [stderr]    |                                                ^^^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stderr] 
[INFO] [stderr] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stderr]   --> src/main.rs:59:13
[INFO] [stderr]    |
[INFO] [stderr] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stderr]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stderr] 51 |     match cache.get(n) {
[INFO] [stderr]    |           ----- immutable borrow occurs here
[INFO] [stderr] 52 |         Some(n) => n,
[INFO] [stderr]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stderr] ...
[INFO] [stderr] 59 |             cache.push(res);
[INFO] [stderr]    |             ^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stderr] 
[INFO] [stderr] error[E0515]: cannot return reference to temporary value
[INFO] [stderr]   --> src/main.rs:60:20
[INFO] [stderr]    |
[INFO] [stderr] 60 |             return &cache[n].clone();
[INFO] [stderr]    |                    ^----------------
[INFO] [stderr]    |                    ||
[INFO] [stderr]    |                    |temporary value created here
[INFO] [stderr]    |                    returns a reference to data owned by the current function
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 4 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0502, E0515.
[INFO] [stderr] For more information about an error, try `rustc --explain E0502`.
[INFO] [stderr] error: could not compile `pong`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] warning: unused import: `std::io`
[INFO] [stderr]  --> src/main.rs:3:5
[INFO] [stderr]   |
[INFO] [stderr] 3 | use std::io;
[INFO] [stderr]   |     ^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `rand::Rng`
[INFO] [stderr]  --> src/main.rs:4:5
[INFO] [stderr]   |
[INFO] [stderr] 4 | use rand::Rng;
[INFO] [stderr]   |     ^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `std::cmp::Ordering`
[INFO] [stderr]  --> src/main.rs:5:5
[INFO] [stderr]   |
[INFO] [stderr] 5 | use std::cmp::Ordering;
[INFO] [stderr]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: unused import: `Assign`
[INFO] [stderr]  --> src/main.rs:6:11
[INFO] [stderr]   |
[INFO] [stderr] 6 | use rug::{Assign, Integer};
[INFO] [stderr]   |           ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stderr]   --> src/main.rs:57:22
[INFO] [stderr]    |
[INFO] [stderr] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stderr]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stderr] 51 |     match cache.get(n) {
[INFO] [stderr]    |           ----- immutable borrow occurs here
[INFO] [stderr] 52 |         Some(n) => n,
[INFO] [stderr]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stderr] ...
[INFO] [stderr] 57 |                 m => fib(m-2, cache).clone() + fib(m - 1, cache).clone()
[INFO] [stderr]    |                      ^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stderr] 
[INFO] [stderr] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stderr]   --> src/main.rs:57:48
[INFO] [stderr]    |
[INFO] [stderr] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stderr]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stderr] 51 |     match cache.get(n) {
[INFO] [stderr]    |           ----- immutable borrow occurs here
[INFO] [stderr] 52 |         Some(n) => n,
[INFO] [stderr]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stderr] ...
[INFO] [stderr] 57 |                 m => fib(m-2, cache).clone() + fib(m - 1, cache).clone()
[INFO] [stderr]    |                                                ^^^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stderr] 
[INFO] [stderr] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stderr]   --> src/main.rs:59:13
[INFO] [stderr]    |
[INFO] [stderr] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stderr]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stderr] 51 |     match cache.get(n) {
[INFO] [stderr]    |           ----- immutable borrow occurs here
[INFO] [stderr] 52 |         Some(n) => n,
[INFO] [stderr]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stderr] ...
[INFO] [stderr] 59 |             cache.push(res);
[INFO] [stderr]    |             ^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stderr] 
[INFO] [stderr] error[E0515]: cannot return reference to temporary value
[INFO] [stderr]   --> src/main.rs:60:20
[INFO] [stderr]    |
[INFO] [stderr] 60 |             return &cache[n].clone();
[INFO] [stderr]    |                    ^----------------
[INFO] [stderr]    |                    ||
[INFO] [stderr]    |                    |temporary value created here
[INFO] [stderr]    |                    returns a reference to data owned by the current function
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 4 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0502, E0515.
[INFO] [stderr] For more information about an error, try `rustc --explain E0502`.
[INFO] [stderr] error: could not compile `pong`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "3251ec01a4f2aac27ce2660d20f6dc8997f74f339461f5181da1c6c7c24441be"`
[INFO] running `"docker" "rm" "-f" "3251ec01a4f2aac27ce2660d20f6dc8997f74f339461f5181da1c6c7c24441be"`
[INFO] [stdout] 3251ec01a4f2aac27ce2660d20f6dc8997f74f339461f5181da1c6c7c24441be
