[INFO] updating cached repository LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust
[INFO] running `"git" "fetch" "--all"`
[INFO] [stdout] Fetching origin
[INFO] [stderr] From git://github.com/LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust
[INFO] [stderr]  * branch            HEAD       -> FETCH_HEAD
[INFO] running `"git" "clone" "work/cache/sources/gh/LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust" "work/ex/beta-1.38-1/sources/1.37.0/gh/LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/1.37.0/gh/LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust'...
[INFO] [stderr] done.
[INFO] running `"git" "clone" "work/cache/sources/gh/LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust" "work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust"`
[INFO] [stderr] Cloning into 'work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust'...
[INFO] [stderr] done.
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 19489252d5d7b675fb202a92ea9aa20395addd31
[INFO] sha for GitHub repo LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust: 19489252d5d7b675fb202a92ea9aa20395addd31
[INFO] validating manifest of LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust
[INFO] finished frobbing LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust
[INFO] frobbed toml for LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust written to work/ex/beta-1.38-1/sources/1.37.0/gh/LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust/Cargo.toml
[INFO] started frobbing LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust
[INFO] finished frobbing LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust
[INFO] frobbed toml for LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust written to work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust/Cargo.toml
[INFO] crate LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust already has a lockfile, it will not be regenerated
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust against beta-2019-08-13 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-2/beta-2019-08-13:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/beta-2019-08-13/gh/LooMaclin/reproduce_make_mut_inspection_bug_intellij_idea_rust:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+beta-2019-08-13" "build" "--frozen"`
[INFO] [stdout] 02f149f3b70e42f2780a3f051ff224f26411caf965ebad56b850bf5028e4938d
[INFO] running `"docker" "start" "-a" "02f149f3b70e42f2780a3f051ff224f26411caf965ebad56b850bf5028e4938d"`
[INFO] [stderr]    Compiling reproduce_make_mut_inspection_bug_intellij_idea_rust v0.1.0 (/opt/crater/workdir)
[INFO] [stderr] warning: unused variable: `b`
[INFO] [stderr]  --> src/main.rs:2:12
[INFO] [stderr]   |
[INFO] [stderr] 2 | fn test((a,b): (String, String)) {
[INFO] [stderr]   |            ^ help: consider prefixing with an underscore: `_b`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] error[E0596]: cannot borrow `a` as mutable, as it is not declared as mutable
[INFO] [stderr]  --> src/main.rs:3:5
[INFO] [stderr]   |
[INFO] [stderr] 2 | fn test((a,b): (String, String)) {
[INFO] [stderr]   |          - help: consider changing this to be mutable: `mut a`
[INFO] [stderr] 3 |     a.insert(0, 'b');
[INFO] [stderr]   |     ^ cannot borrow as mutable
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0596`.
[INFO] [stderr] error: Could not compile `reproduce_make_mut_inspection_bug_intellij_idea_rust`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "02f149f3b70e42f2780a3f051ff224f26411caf965ebad56b850bf5028e4938d"`
[INFO] running `"docker" "rm" "-f" "02f149f3b70e42f2780a3f051ff224f26411caf965ebad56b850bf5028e4938d"`
[INFO] [stdout] 02f149f3b70e42f2780a3f051ff224f26411caf965ebad56b850bf5028e4938d