[INFO] cloning repository https://github.com/dhoepelman/rust-pong
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/dhoepelman/rust-pong" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdhoepelman%2Frust-pong", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdhoepelman%2Frust-pong'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c137445cb4b13ef72b217eb3bb5075ee9e1d1ecc
[INFO] checking dhoepelman/rust-pong/c137445cb4b13ef72b217eb3bb5075ee9e1d1ecc against master#4eb62535fc12dd1a63fd43a4173e224e79313c4d for pr-158816
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdhoepelman%2Frust-pong" "/workspace/builds/worker-1-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc1/source'...
[INFO] [stderr] done.
[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-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/dhoepelman/rust-pong on toolchain 4eb62535fc12dd1a63fd43a4173e224e79313c4d
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4eb62535fc12dd1a63fd43a4173e224e79313c4d" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/dhoepelman/rust-pong 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" "+4eb62535fc12dd1a63fd43a4173e224e79313c4d" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded fuchsia-cprng v0.1.0
[INFO] [stderr]   Downloaded rug v0.6.0
[INFO] [stderr]   Downloaded libc v0.2.48
[INFO] [stderr]   Downloaded gmp-mpfr-sys v1.1.10
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,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" "-m" "1610612736" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:3d5ced03c013a94a2f102a4510f48a6e9184255caf5fd8244f58017bde7f5210" "sleep" "infinity", kill_on_drop: false }`
[INFO] [stdout] 1b4f07aff545ddfee8c775fcaa6167ed6904b6f560359f922c984d38d9f71b46
[INFO] running `Command { std: "docker" "start" "1b4f07aff545ddfee8c775fcaa6167ed6904b6f560359f922c984d38d9f71b46", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1b4f07aff545ddfee8c775fcaa6167ed6904b6f560359f922c984d38d9f71b46", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-w" "/opt/rustwide/workdir" "--user" "0:0" "1b4f07aff545ddfee8c775fcaa6167ed6904b6f560359f922c984d38d9f71b46" "/opt/rustwide/cargo-home/bin/cargo" "+4eb62535fc12dd1a63fd43a4173e224e79313c4d" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1b4f07aff545ddfee8c775fcaa6167ed6904b6f560359f922c984d38d9f71b46", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "exec" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-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" "-w" "/opt/rustwide/workdir" "--user" "0:0" "1b4f07aff545ddfee8c775fcaa6167ed6904b6f560359f922c984d38d9f71b46" "/opt/rustwide/cargo-home/bin/cargo" "+4eb62535fc12dd1a63fd43a4173e224e79313c4d" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.48
[INFO] [stderr]    Compiling gmp-mpfr-sys v1.1.10
[INFO] [stderr]    Compiling rug v0.6.0
[INFO] [stderr]     Checking rand v0.4.6
[INFO] [stderr]     Checking pong v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::io`
[INFO] [stdout]  --> src/main.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::io;
[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 import: `rand::Rng`
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use rand::Rng;
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::cmp::Ordering`
[INFO] [stdout]  --> src/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::cmp::Ordering;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Assign`
[INFO] [stdout]  --> src/main.rs:6:11
[INFO] [stdout]   |
[INFO] [stdout] 6 | use rug::{Assign, Integer};
[INFO] [stdout]   |           ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io`
[INFO] [stdout]  --> src/main.rs:3:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::io;
[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 import: `rand::Rng`
[INFO] [stdout]  --> src/main.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use rand::Rng;
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::cmp::Ordering`
[INFO] [stdout]  --> src/main.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::cmp::Ordering;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Assign`
[INFO] [stdout]  --> src/main.rs:6:11
[INFO] [stdout]   |
[INFO] [stdout] 6 | use rug::{Assign, Integer};
[INFO] [stdout]   |           ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stdout]   --> src/main.rs:57:22
[INFO] [stdout]    |
[INFO] [stdout] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stdout]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stdout] 51 |     match cache.get(n) {
[INFO] [stdout]    |           ----- immutable borrow occurs here
[INFO] [stdout] 52 |         Some(n) => n,
[INFO] [stdout]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stdout] ...
[INFO] [stdout] 57 |                 m => fib(m-2, cache).clone() + fib(m - 1, cache).clone()
[INFO] [stdout]    |                      ^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stdout]   --> src/main.rs:57:48
[INFO] [stdout]    |
[INFO] [stdout] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stdout]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stdout] 51 |     match cache.get(n) {
[INFO] [stdout]    |           ----- immutable borrow occurs here
[INFO] [stdout] 52 |         Some(n) => n,
[INFO] [stdout]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stdout] ...
[INFO] [stdout] 57 |                 m => fib(m-2, cache).clone() + fib(m - 1, cache).clone()
[INFO] [stdout]    |                                                ^^^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stdout]   --> src/main.rs:59:13
[INFO] [stdout]    |
[INFO] [stdout] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stdout]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stdout] 51 |     match cache.get(n) {
[INFO] [stdout]    |           ----- immutable borrow occurs here
[INFO] [stdout] 52 |         Some(n) => n,
[INFO] [stdout]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stdout] ...
[INFO] [stdout] 59 |             cache.push(res);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0515]: cannot return reference to temporary value
[INFO] [stdout]   --> src/main.rs:60:20
[INFO] [stdout]    |
[INFO] [stdout] 60 |             return &cache[n].clone();
[INFO] [stdout]    |                    ^----------------
[INFO] [stdout]    |                    ||
[INFO] [stdout]    |                    |temporary value created here
[INFO] [stdout]    |                    returns a reference to data owned by the current function
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0502, E0515.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0502`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `pong` (bin "pong" test) due to 4 previous errors; 4 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stdout]   --> src/main.rs:57:22
[INFO] [stdout]    |
[INFO] [stdout] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stdout]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stdout] 51 |     match cache.get(n) {
[INFO] [stdout]    |           ----- immutable borrow occurs here
[INFO] [stdout] 52 |         Some(n) => n,
[INFO] [stdout]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stdout] ...
[INFO] [stdout] 57 |                 m => fib(m-2, cache).clone() + fib(m - 1, cache).clone()
[INFO] [stdout]    |                      ^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `pong` (bin "pong") due to 4 previous errors; 4 warnings emitted
[INFO] [stdout] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stdout]   --> src/main.rs:57:48
[INFO] [stdout]    |
[INFO] [stdout] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stdout]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stdout] 51 |     match cache.get(n) {
[INFO] [stdout]    |           ----- immutable borrow occurs here
[INFO] [stdout] 52 |         Some(n) => n,
[INFO] [stdout]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stdout] ...
[INFO] [stdout] 57 |                 m => fib(m-2, cache).clone() + fib(m - 1, cache).clone()
[INFO] [stdout]    |                                                ^^^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0502]: cannot borrow `*cache` as mutable because it is also borrowed as immutable
[INFO] [stdout]   --> src/main.rs:59:13
[INFO] [stdout]    |
[INFO] [stdout] 50 | fn fib(n: usize, cache: &mut Vec<Integer>) -> &Integer {
[INFO] [stdout]    |                         - let's call the lifetime of this reference `'1`
[INFO] [stdout] 51 |     match cache.get(n) {
[INFO] [stdout]    |           ----- immutable borrow occurs here
[INFO] [stdout] 52 |         Some(n) => n,
[INFO] [stdout]    |                    - returning this value requires that `*cache` is borrowed for `'1`
[INFO] [stdout] ...
[INFO] [stdout] 59 |             cache.push(res);
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^ mutable borrow occurs here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0515]: cannot return reference to temporary value
[INFO] [stdout]   --> src/main.rs:60:20
[INFO] [stdout]    |
[INFO] [stdout] 60 |             return &cache[n].clone();
[INFO] [stdout]    |                    ^----------------
[INFO] [stdout]    |                    ||
[INFO] [stdout]    |                    |temporary value created here
[INFO] [stdout]    |                    returns a reference to data owned by the current function
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0502, E0515.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0502`.
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "1b4f07aff545ddfee8c775fcaa6167ed6904b6f560359f922c984d38d9f71b46", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1b4f07aff545ddfee8c775fcaa6167ed6904b6f560359f922c984d38d9f71b46", kill_on_drop: false }`
[INFO] [stdout] 1b4f07aff545ddfee8c775fcaa6167ed6904b6f560359f922c984d38d9f71b46
