Dec 17 20:28:08.609 INFO checking lucke84/playing_around_with_rust against try#0b8c5828f68d7b2840b81fa51239346dc97fef5a for pr-54252
Dec 17 20:28:08.610 INFO running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/pr-54252/worker-1/try#0b8c5828f68d7b2840b81fa51239346dc97fef5a:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/pr-54252/sources/try#0b8c5828f68d7b2840b81fa51239346dc97fef5a/gh/lucke84/playing_around_with_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=forbid" "-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" "+0b8c5828f68d7b2840b81fa51239346dc97fef5a-alt" "check" "--frozen" "--all" "--all-targets"`
Dec 17 20:28:08.758 INFO [stdout] 87a2a4eccad084d5a9980c4fb3d8129e81d892abaa4bd9c608b0dee0161b2758
Dec 17 20:28:08.762 INFO running `"docker" "start" "-a" "87a2a4eccad084d5a9980c4fb3d8129e81d892abaa4bd9c608b0dee0161b2758"`
Dec 17 20:28:09.709 INFO [stderr]     Checking playing_around_with_rust v0.0.1 (/opt/crater/workdir)
Dec 17 20:28:10.116 INFO [stderr] warning: unnecessary parentheses around assigned value
Dec 17 20:28:10.116 INFO [stderr]   --> src/main.rs:37:13
Dec 17 20:28:10.116 INFO [stderr]    |
Dec 17 20:28:10.116 INFO [stderr] 37 |     let j = (i = 6);                            // the value of an assignment is an empty tuple: so j has the value (), not 6
Dec 17 20:28:10.116 INFO [stderr]    |             ^^^^^^^ help: remove these parentheses
Dec 17 20:28:10.116 INFO [stderr]    |
Dec 17 20:28:10.116 INFO [stderr]    = note: #[warn(unused_parens)] on by default
Dec 17 20:28:10.116 INFO [stderr] 
Dec 17 20:28:10.156 INFO [stderr] warning: unnecessary parentheses around assigned value
Dec 17 20:28:10.156 INFO [stderr]   --> src/main.rs:37:13
Dec 17 20:28:10.156 INFO [stderr]    |
Dec 17 20:28:10.156 INFO [stderr] 37 |     let j = (i = 6);                            // the value of an assignment is an empty tuple: so j has the value (), not 6
Dec 17 20:28:10.156 INFO [stderr]    |             ^^^^^^^ help: remove these parentheses
Dec 17 20:28:10.156 INFO [stderr]    |
Dec 17 20:28:10.156 INFO [stderr]    = note: #[warn(unused_parens)] on by default
Dec 17 20:28:10.156 INFO [stderr] 
Dec 17 20:28:10.192 INFO [stderr] warning: unreachable expression
Dec 17 20:28:10.192 INFO [stderr]    --> src/main.rs:137:5
Dec 17 20:28:10.192 INFO [stderr]     |
Dec 17 20:28:10.192 INFO [stderr] 137 |     x                                           // never executed
Dec 17 20:28:10.192 INFO [stderr]     |     ^
Dec 17 20:28:10.204 INFO [stderr]     |
Dec 17 20:28:10.204 INFO [stderr]     = note: #[warn(unreachable_code)] on by default
Dec 17 20:28:10.204 INFO [stderr] 
Dec 17 20:28:10.210 INFO [stderr] warning: unused variable: `a`
Dec 17 20:28:10.210 INFO [stderr]  --> src/main.rs:7:9
Dec 17 20:28:10.210 INFO [stderr]   |
Dec 17 20:28:10.210 INFO [stderr] 7 |     let a = 1;                                  // type i32 is infered
Dec 17 20:28:10.210 INFO [stderr]   |         ^ help: consider using `_a` instead
Dec 17 20:28:10.210 INFO [stderr]   |
Dec 17 20:28:10.210 INFO [stderr]   = note: #[warn(unused_variables)] on by default
Dec 17 20:28:10.210 INFO [stderr] 
Dec 17 20:28:10.210 INFO [stderr] warning: unused variable: `b`
Dec 17 20:28:10.210 INFO [stderr]  --> src/main.rs:8:9
Dec 17 20:28:10.210 INFO [stderr]   |
Dec 17 20:28:10.210 INFO [stderr] 8 |     let b: i32 = 2;                             // type i32 is explicitly declared
Dec 17 20:28:10.210 INFO [stderr]   |         ^ help: consider using `_b` instead
Dec 17 20:28:10.210 INFO [stderr] 
Dec 17 20:28:10.210 INFO [stderr] warning: unused variable: `c`
Dec 17 20:28:10.210 INFO [stderr]   --> src/main.rs:10:10
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 10 |     let (c, d) = (3, 4);                        // variable bindings of multiple vars at the same time
Dec 17 20:28:10.211 INFO [stderr]    |          ^ help: consider using `_c` instead
Dec 17 20:28:10.211 INFO [stderr] 
Dec 17 20:28:10.211 INFO [stderr] warning: unused variable: `d`
Dec 17 20:28:10.211 INFO [stderr]   --> src/main.rs:10:13
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 10 |     let (c, d) = (3, 4);                        // variable bindings of multiple vars at the same time
Dec 17 20:28:10.211 INFO [stderr]    |             ^ help: consider using `_d` instead
Dec 17 20:28:10.211 INFO [stderr] 
Dec 17 20:28:10.211 INFO [stderr] warning: unused variable: `e`
Dec 17 20:28:10.211 INFO [stderr]   --> src/main.rs:12:9
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 12 |     let e: i32;
Dec 17 20:28:10.211 INFO [stderr]    |         ^ help: consider using `_e` instead
Dec 17 20:28:10.211 INFO [stderr] 
Dec 17 20:28:10.211 INFO [stderr] warning: variable `f` is assigned to, but never used
Dec 17 20:28:10.211 INFO [stderr]   --> src/main.rs:18:13
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 18 |     let mut f = 5;                              // make variable mutable
Dec 17 20:28:10.211 INFO [stderr]    |             ^
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr]    = note: consider using `_f` instead
Dec 17 20:28:10.211 INFO [stderr] 
Dec 17 20:28:10.211 INFO [stderr] warning: value assigned to `f` is never read
Dec 17 20:28:10.211 INFO [stderr]   --> src/main.rs:19:5
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 19 |     f = 6;                                      // now I can assign a new value (of the same type!) to this variable
Dec 17 20:28:10.211 INFO [stderr]    |     ^
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr]    = note: #[warn(unused_assignments)] on by default
Dec 17 20:28:10.211 INFO [stderr] 
Dec 17 20:28:10.211 INFO [stderr] warning: unused variable: `f`
Dec 17 20:28:10.211 INFO [stderr]   --> src/main.rs:20:9
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 20 |     let f = "Look, I am text now";              // shadowing, and changing type!
Dec 17 20:28:10.211 INFO [stderr]    |         ^ help: consider using `_f` instead
Dec 17 20:28:10.211 INFO [stderr] 
Dec 17 20:28:10.211 INFO [stderr] warning: value assigned to `i` is never read
Dec 17 20:28:10.211 INFO [stderr]   --> src/main.rs:36:13
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 36 |     let mut i = 5;
Dec 17 20:28:10.211 INFO [stderr]    |             ^
Dec 17 20:28:10.211 INFO [stderr] 
Dec 17 20:28:10.211 INFO [stderr] warning: unused variable: `j`
Dec 17 20:28:10.211 INFO [stderr]   --> src/main.rs:37:9
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 37 |     let j = (i = 6);                            // the value of an assignment is an empty tuple: so j has the value (), not 6
Dec 17 20:28:10.211 INFO [stderr]    |         ^ help: consider using `_j` instead
Dec 17 20:28:10.211 INFO [stderr] 
Dec 17 20:28:10.211 INFO [stderr] warning: unused variable: `a_boolean`
Dec 17 20:28:10.211 INFO [stderr]   --> src/main.rs:59:9
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 59 |     let a_boolean = true;                         // with inference
Dec 17 20:28:10.211 INFO [stderr]    |         ^^^^^^^^^ help: consider using `_a_boolean` instead
Dec 17 20:28:10.211 INFO [stderr] 
Dec 17 20:28:10.211 INFO [stderr] warning: unused variable: `another_boolean`
Dec 17 20:28:10.211 INFO [stderr]   --> src/main.rs:60:9
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 60 |     let another_boolean: bool = false;            // without inference
Dec 17 20:28:10.211 INFO [stderr]    |         ^^^^^^^^^^^^^^^ help: consider using `_another_boolean` instead
Dec 17 20:28:10.211 INFO [stderr] 
Dec 17 20:28:10.211 INFO [stderr] warning: unused variable: `this_is_a_char`
Dec 17 20:28:10.211 INFO [stderr]   --> src/main.rs:63:9
Dec 17 20:28:10.211 INFO [stderr]    |
Dec 17 20:28:10.211 INFO [stderr] 63 |     let this_is_a_char = 'x';                    // delimited by a single quote/tick
Dec 17 20:28:10.212 INFO [stderr]    |         ^^^^^^^^^^^^^^ help: consider using `_this_is_a_char` instead
Dec 17 20:28:10.212 INFO [stderr] 
Dec 17 20:28:10.212 INFO [stderr] warning: unused variable: `two_hearts_char`
Dec 17 20:28:10.212 INFO [stderr]   --> src/main.rs:64:9
Dec 17 20:28:10.212 INFO [stderr]    |
Dec 17 20:28:10.212 INFO [stderr] 64 |     let two_hearts_char = '💕';                   // any unicode char (due to the fact that they are UTF-32, all chars are 4 bytes instead of just 1)
Dec 17 20:28:10.212 INFO [stderr]    |         ^^^^^^^^^^^^^^^ help: consider using `_two_hearts_char` instead
Dec 17 20:28:10.212 INFO [stderr] 
Dec 17 20:28:10.212 INFO [stderr] warning: unused variable: `an_integer`
Dec 17 20:28:10.212 INFO [stderr]   --> src/main.rs:67:9
Dec 17 20:28:10.212 INFO [stderr]    |
Dec 17 20:28:10.212 INFO [stderr] 67 |     let an_integer = 42;                         // default with inference (type i32 - The 32-bit signed integer type)
Dec 17 20:28:10.212 INFO [stderr]    |         ^^^^^^^^^^ help: consider using `_an_integer` instead
Dec 17 20:28:10.212 INFO [stderr] 
Dec 17 20:28:10.212 INFO [stderr] warning: unused variable: `a_float`
Dec 17 20:28:10.212 INFO [stderr]   --> src/main.rs:68:9
Dec 17 20:28:10.212 INFO [stderr]    |
Dec 17 20:28:10.212 INFO [stderr] 68 |     let a_float = 1.0;                           // default with inference (type f64 - The 64-bit floating point type)
Dec 17 20:28:10.212 INFO [stderr]    |         ^^^^^^^ help: consider using `_a_float` instead
Dec 17 20:28:10.212 INFO [stderr] 
Dec 17 20:28:10.212 INFO [stderr] warning: unused variable: `complete_slice`
Dec 17 20:28:10.212 INFO [stderr]   --> src/main.rs:99:9
Dec 17 20:28:10.212 INFO [stderr]    |
Dec 17 20:28:10.212 INFO [stderr] 99 |     let complete_slice = &mutable_array[..];                  // [5, 7, 3, 23, 11]
Dec 17 20:28:10.216 INFO [stderr]    |         ^^^^^^^^^^^^^^ help: consider using `_complete_slice` instead
Dec 17 20:28:10.216 INFO [stderr] 
Dec 17 20:28:10.216 INFO [stderr] warning: unused variable: `partial_slice`
Dec 17 20:28:10.216 INFO [stderr]    --> src/main.rs:100:9
Dec 17 20:28:10.216 INFO [stderr]     |
Dec 17 20:28:10.216 INFO [stderr] 100 |     let partial_slice = &mutable_array[1..3];                 // [7, 4] - from item at index 1 to item at index 3 (excluded)
Dec 17 20:28:10.216 INFO [stderr]     |         ^^^^^^^^^^^^^ help: consider using `_partial_slice` instead
Dec 17 20:28:10.216 INFO [stderr] 
Dec 17 20:28:10.216 INFO [stderr] warning: unused variable: `from_item_till_end_slice`
Dec 17 20:28:10.216 INFO [stderr]    --> src/main.rs:101:9
Dec 17 20:28:10.216 INFO [stderr]     |
Dec 17 20:28:10.216 INFO [stderr] 101 |     let from_item_till_end_slice = &mutable_array[1..];       // [7, 4, 23, 11]
Dec 17 20:28:10.216 INFO [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `_from_item_till_end_slice` instead
Dec 17 20:28:10.216 INFO [stderr] 
Dec 17 20:28:10.216 INFO [stderr] warning: unused variable: `from_beginning_till_item_slice`
Dec 17 20:28:10.216 INFO [stderr]    --> src/main.rs:102:9
Dec 17 20:28:10.216 INFO [stderr]     |
Dec 17 20:28:10.216 INFO [stderr] 102 |     let from_beginning_till_item_slice = &mutable_array[..2]; // [5, 7]
Dec 17 20:28:10.216 INFO [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `_from_beginning_till_item_slice` instead
Dec 17 20:28:10.216 INFO [stderr] 
Dec 17 20:28:10.216 INFO [stderr] warning: unused variable: `tuple_one`
Dec 17 20:28:10.216 INFO [stderr]    --> src/main.rs:106:9
Dec 17 20:28:10.216 INFO [stderr]     |
Dec 17 20:28:10.216 INFO [stderr] 106 |     let tuple_one = (1, "one");
Dec 17 20:28:10.216 INFO [stderr]     |         ^^^^^^^^^ help: consider using `_tuple_one` instead
Dec 17 20:28:10.216 INFO [stderr] 
Dec 17 20:28:10.216 INFO [stderr] warning: value assigned to `tuple_xy` is never read
Dec 17 20:28:10.216 INFO [stderr]    --> src/main.rs:110:13
Dec 17 20:28:10.216 INFO [stderr]     |
Dec 17 20:28:10.216 INFO [stderr] 110 |     let mut tuple_xy = (0, "zero");
Dec 17 20:28:10.216 INFO [stderr]     |             ^^^^^^^^
Dec 17 20:28:10.216 INFO [stderr] 
Dec 17 20:28:10.216 INFO [stderr] warning: unused variable: `tuple_second_item`
Dec 17 20:28:10.216 INFO [stderr]    --> src/main.rs:123:9
Dec 17 20:28:10.216 INFO [stderr]     |
Dec 17 20:28:10.216 INFO [stderr] 123 |     let tuple_second_item = tuple_xy.1;
Dec 17 20:28:10.216 INFO [stderr]     |         ^^^^^^^^^^^^^^^^^ help: consider using `_tuple_second_item` instead
Dec 17 20:28:10.216 INFO [stderr] 
Dec 17 20:28:10.216 INFO [stderr] warning: unused variable: `x`
Dec 17 20:28:10.216 INFO [stderr]    --> src/main.rs:135:22
Dec 17 20:28:10.216 INFO [stderr]     |
Dec 17 20:28:10.216 INFO [stderr] 135 | fn always_return_one(x: i32) -> i32 {
Dec 17 20:28:10.216 INFO [stderr]     |                      ^ help: consider using `_x` instead
Dec 17 20:28:10.216 INFO [stderr] 
Dec 17 20:28:10.219 INFO [stderr] warning: variable does not need to be mutable
Dec 17 20:28:10.219 INFO [stderr]   --> src/main.rs:87:9
Dec 17 20:28:10.219 INFO [stderr]    |
Dec 17 20:28:10.219 INFO [stderr] 87 |     let mut mutable_array = [1.5, 2.3, 3.0]; // type [f64; 3]
Dec 17 20:28:10.219 INFO [stderr]    |         ----^^^^^^^^^^^^^
Dec 17 20:28:10.219 INFO [stderr]    |         |
Dec 17 20:28:10.219 INFO [stderr]    |         help: remove this `mut`
Dec 17 20:28:10.226 INFO [stderr] warning: unreachable expression
Dec 17 20:28:10.226 INFO [stderr]    --> src/main.rs:137:5
Dec 17 20:28:10.226 INFO [stderr]     |
Dec 17 20:28:10.226 INFO [stderr] 137 |     x                                           // never executed
Dec 17 20:28:10.226 INFO [stderr]     |     ^
Dec 17 20:28:10.226 INFO [stderr]    |
Dec 17 20:28:10.226 INFO [stderr]    = note: #[warn(unused_mut)] on by default
Dec 17 20:28:10.226 INFO [stderr] 
Dec 17 20:28:10.227 INFO [stderr] warning: function is never used: `diverges`
Dec 17 20:28:10.227 INFO [stderr]    --> src/main.rs:140:1
Dec 17 20:28:10.227 INFO [stderr]     |
Dec 17 20:28:10.227 INFO [stderr] 140 | fn diverges() -> ! {                            // defines the return type as "diverges" using the bang symbol
Dec 17 20:28:10.227 INFO [stderr]     | ^^^^^^^^^^^^^^^^^^
Dec 17 20:28:10.227 INFO [stderr]     |
Dec 17 20:28:10.227 INFO [stderr]     = note: #[warn(dead_code)] on by default
Dec 17 20:28:10.227 INFO [stderr] 
Dec 17 20:28:10.228 INFO [stderr]     |
Dec 17 20:28:10.228 INFO [stderr]     = note: #[warn(unreachable_code)] on by default
Dec 17 20:28:10.228 INFO [stderr] 
Dec 17 20:28:10.238 INFO [stderr] warning: unused variable: `a`
Dec 17 20:28:10.238 INFO [stderr]  --> src/main.rs:7:9
Dec 17 20:28:10.238 INFO [stderr]   |
Dec 17 20:28:10.238 INFO [stderr] 7 |     let a = 1;                                  // type i32 is infered
Dec 17 20:28:10.238 INFO [stderr]   |         ^ help: consider using `_a` instead
Dec 17 20:28:10.238 INFO [stderr]   |
Dec 17 20:28:10.238 INFO [stderr]   = note: #[warn(unused_variables)] on by default
Dec 17 20:28:10.238 INFO [stderr] 
Dec 17 20:28:10.238 INFO [stderr] warning: unused variable: `b`
Dec 17 20:28:10.238 INFO [stderr]  --> src/main.rs:8:9
Dec 17 20:28:10.238 INFO [stderr]   |
Dec 17 20:28:10.238 INFO [stderr] 8 |     let b: i32 = 2;                             // type i32 is explicitly declared
Dec 17 20:28:10.238 INFO [stderr]   |         ^ help: consider using `_b` instead
Dec 17 20:28:10.238 INFO [stderr] 
Dec 17 20:28:10.238 INFO [stderr] warning: unused variable: `c`
Dec 17 20:28:10.238 INFO [stderr]   --> src/main.rs:10:10
Dec 17 20:28:10.238 INFO [stderr]    |
Dec 17 20:28:10.238 INFO [stderr] 10 |     let (c, d) = (3, 4);                        // variable bindings of multiple vars at the same time
Dec 17 20:28:10.238 INFO [stderr]    |          ^ help: consider using `_c` instead
Dec 17 20:28:10.238 INFO [stderr] 
Dec 17 20:28:10.238 INFO [stderr] warning: unused variable: `d`
Dec 17 20:28:10.238 INFO [stderr]   --> src/main.rs:10:13
Dec 17 20:28:10.238 INFO [stderr]    |
Dec 17 20:28:10.238 INFO [stderr] 10 |     let (c, d) = (3, 4);                        // variable bindings of multiple vars at the same time
Dec 17 20:28:10.238 INFO [stderr]    |             ^ help: consider using `_d` instead
Dec 17 20:28:10.238 INFO [stderr] 
Dec 17 20:28:10.238 INFO [stderr] warning: unused variable: `e`
Dec 17 20:28:10.238 INFO [stderr]   --> src/main.rs:12:9
Dec 17 20:28:10.238 INFO [stderr]    |
Dec 17 20:28:10.238 INFO [stderr] 12 |     let e: i32;
Dec 17 20:28:10.238 INFO [stderr]    |         ^ help: consider using `_e` instead
Dec 17 20:28:10.238 INFO [stderr] 
Dec 17 20:28:10.238 INFO [stderr] warning: variable `f` is assigned to, but never used
Dec 17 20:28:10.238 INFO [stderr]   --> src/main.rs:18:13
Dec 17 20:28:10.238 INFO [stderr]    |
Dec 17 20:28:10.238 INFO [stderr] 18 |     let mut f = 5;                              // make variable mutable
Dec 17 20:28:10.238 INFO [stderr]    |             ^
Dec 17 20:28:10.238 INFO [stderr]    |
Dec 17 20:28:10.238 INFO [stderr]    = note: consider using `_f` instead
Dec 17 20:28:10.238 INFO [stderr] 
Dec 17 20:28:10.238 INFO [stderr] warning: value assigned to `f` is never read
Dec 17 20:28:10.238 INFO [stderr]   --> src/main.rs:19:5
Dec 17 20:28:10.238 INFO [stderr]    |
Dec 17 20:28:10.238 INFO [stderr] 19 |     f = 6;                                      // now I can assign a new value (of the same type!) to this variable
Dec 17 20:28:10.238 INFO [stderr]    |     ^
Dec 17 20:28:10.238 INFO [stderr]    |
Dec 17 20:28:10.238 INFO [stderr]    = note: #[warn(unused_assignments)] on by default
Dec 17 20:28:10.238 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `f`
Dec 17 20:28:10.239 INFO [stderr]   --> src/main.rs:20:9
Dec 17 20:28:10.239 INFO [stderr]    |
Dec 17 20:28:10.239 INFO [stderr] 20 |     let f = "Look, I am text now";              // shadowing, and changing type!
Dec 17 20:28:10.239 INFO [stderr]    |         ^ help: consider using `_f` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: value assigned to `i` is never read
Dec 17 20:28:10.239 INFO [stderr]   --> src/main.rs:36:13
Dec 17 20:28:10.239 INFO [stderr]    |
Dec 17 20:28:10.239 INFO [stderr] 36 |     let mut i = 5;
Dec 17 20:28:10.239 INFO [stderr]    |             ^
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `j`
Dec 17 20:28:10.239 INFO [stderr]   --> src/main.rs:37:9
Dec 17 20:28:10.239 INFO [stderr]    |
Dec 17 20:28:10.239 INFO [stderr] 37 |     let j = (i = 6);                            // the value of an assignment is an empty tuple: so j has the value (), not 6
Dec 17 20:28:10.239 INFO [stderr]    |         ^ help: consider using `_j` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `a_boolean`
Dec 17 20:28:10.239 INFO [stderr]   --> src/main.rs:59:9
Dec 17 20:28:10.239 INFO [stderr]    |
Dec 17 20:28:10.239 INFO [stderr] 59 |     let a_boolean = true;                         // with inference
Dec 17 20:28:10.239 INFO [stderr]    |         ^^^^^^^^^ help: consider using `_a_boolean` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `another_boolean`
Dec 17 20:28:10.239 INFO [stderr]   --> src/main.rs:60:9
Dec 17 20:28:10.239 INFO [stderr]    |
Dec 17 20:28:10.239 INFO [stderr] 60 |     let another_boolean: bool = false;            // without inference
Dec 17 20:28:10.239 INFO [stderr]    |         ^^^^^^^^^^^^^^^ help: consider using `_another_boolean` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `this_is_a_char`
Dec 17 20:28:10.239 INFO [stderr]   --> src/main.rs:63:9
Dec 17 20:28:10.239 INFO [stderr]    |
Dec 17 20:28:10.239 INFO [stderr] 63 |     let this_is_a_char = 'x';                    // delimited by a single quote/tick
Dec 17 20:28:10.239 INFO [stderr]    |         ^^^^^^^^^^^^^^ help: consider using `_this_is_a_char` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `two_hearts_char`
Dec 17 20:28:10.239 INFO [stderr]   --> src/main.rs:64:9
Dec 17 20:28:10.239 INFO [stderr]    |
Dec 17 20:28:10.239 INFO [stderr] 64 |     let two_hearts_char = '💕';                   // any unicode char (due to the fact that they are UTF-32, all chars are 4 bytes instead of just 1)
Dec 17 20:28:10.239 INFO [stderr]    |         ^^^^^^^^^^^^^^^ help: consider using `_two_hearts_char` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `an_integer`
Dec 17 20:28:10.239 INFO [stderr]   --> src/main.rs:67:9
Dec 17 20:28:10.239 INFO [stderr]    |
Dec 17 20:28:10.239 INFO [stderr] 67 |     let an_integer = 42;                         // default with inference (type i32 - The 32-bit signed integer type)
Dec 17 20:28:10.239 INFO [stderr]    |         ^^^^^^^^^^ help: consider using `_an_integer` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `a_float`
Dec 17 20:28:10.239 INFO [stderr]   --> src/main.rs:68:9
Dec 17 20:28:10.239 INFO [stderr]    |
Dec 17 20:28:10.239 INFO [stderr] 68 |     let a_float = 1.0;                           // default with inference (type f64 - The 64-bit floating point type)
Dec 17 20:28:10.239 INFO [stderr]    |         ^^^^^^^ help: consider using `_a_float` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `complete_slice`
Dec 17 20:28:10.239 INFO [stderr]   --> src/main.rs:99:9
Dec 17 20:28:10.239 INFO [stderr]    |
Dec 17 20:28:10.239 INFO [stderr] 99 |     let complete_slice = &mutable_array[..];                  // [5, 7, 3, 23, 11]
Dec 17 20:28:10.239 INFO [stderr]    |         ^^^^^^^^^^^^^^ help: consider using `_complete_slice` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `partial_slice`
Dec 17 20:28:10.239 INFO [stderr]    --> src/main.rs:100:9
Dec 17 20:28:10.239 INFO [stderr]     |
Dec 17 20:28:10.239 INFO [stderr] 100 |     let partial_slice = &mutable_array[1..3];                 // [7, 4] - from item at index 1 to item at index 3 (excluded)
Dec 17 20:28:10.239 INFO [stderr]     |         ^^^^^^^^^^^^^ help: consider using `_partial_slice` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.239 INFO [stderr] warning: unused variable: `from_item_till_end_slice`
Dec 17 20:28:10.239 INFO [stderr]    --> src/main.rs:101:9
Dec 17 20:28:10.239 INFO [stderr]     |
Dec 17 20:28:10.239 INFO [stderr] 101 |     let from_item_till_end_slice = &mutable_array[1..];       // [7, 4, 23, 11]
Dec 17 20:28:10.239 INFO [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `_from_item_till_end_slice` instead
Dec 17 20:28:10.239 INFO [stderr] 
Dec 17 20:28:10.240 INFO [stderr] warning: unused variable: `from_beginning_till_item_slice`
Dec 17 20:28:10.240 INFO [stderr]    --> src/main.rs:102:9
Dec 17 20:28:10.240 INFO [stderr]     |
Dec 17 20:28:10.240 INFO [stderr] 102 |     let from_beginning_till_item_slice = &mutable_array[..2]; // [5, 7]
Dec 17 20:28:10.240 INFO [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider using `_from_beginning_till_item_slice` instead
Dec 17 20:28:10.240 INFO [stderr] 
Dec 17 20:28:10.240 INFO [stderr] warning: unused variable: `tuple_one`
Dec 17 20:28:10.240 INFO [stderr]    --> src/main.rs:106:9
Dec 17 20:28:10.240 INFO [stderr]     |
Dec 17 20:28:10.240 INFO [stderr] 106 |     let tuple_one = (1, "one");
Dec 17 20:28:10.240 INFO [stderr]     |         ^^^^^^^^^ help: consider using `_tuple_one` instead
Dec 17 20:28:10.240 INFO [stderr] 
Dec 17 20:28:10.240 INFO [stderr] warning: value assigned to `tuple_xy` is never read
Dec 17 20:28:10.240 INFO [stderr]    --> src/main.rs:110:13
Dec 17 20:28:10.240 INFO [stderr]     |
Dec 17 20:28:10.240 INFO [stderr] 110 |     let mut tuple_xy = (0, "zero");
Dec 17 20:28:10.240 INFO [stderr]     |             ^^^^^^^^
Dec 17 20:28:10.240 INFO [stderr] 
Dec 17 20:28:10.240 INFO [stderr] warning: unused variable: `tuple_second_item`
Dec 17 20:28:10.240 INFO [stderr]    --> src/main.rs:123:9
Dec 17 20:28:10.240 INFO [stderr]     |
Dec 17 20:28:10.240 INFO [stderr] 123 |     let tuple_second_item = tuple_xy.1;
Dec 17 20:28:10.240 INFO [stderr]     |         ^^^^^^^^^^^^^^^^^ help: consider using `_tuple_second_item` instead
Dec 17 20:28:10.240 INFO [stderr] 
Dec 17 20:28:10.240 INFO [stderr] warning: unused variable: `x`
Dec 17 20:28:10.240 INFO [stderr]    --> src/main.rs:135:22
Dec 17 20:28:10.240 INFO [stderr]     |
Dec 17 20:28:10.240 INFO [stderr] 135 | fn always_return_one(x: i32) -> i32 {
Dec 17 20:28:10.240 INFO [stderr]     |                      ^ help: consider using `_x` instead
Dec 17 20:28:10.240 INFO [stderr] 
Dec 17 20:28:10.252 INFO [stderr] warning: variable does not need to be mutable
Dec 17 20:28:10.252 INFO [stderr]   --> src/main.rs:87:9
Dec 17 20:28:10.252 INFO [stderr]    |
Dec 17 20:28:10.252 INFO [stderr] 87 |     let mut mutable_array = [1.5, 2.3, 3.0]; // type [f64; 3]
Dec 17 20:28:10.252 INFO [stderr]    |         ----^^^^^^^^^^^^^
Dec 17 20:28:10.252 INFO [stderr]    |         |
Dec 17 20:28:10.252 INFO [stderr]    |         help: remove this `mut`
Dec 17 20:28:10.253 INFO [stderr]    |
Dec 17 20:28:10.253 INFO [stderr]    = note: #[warn(unused_mut)] on by default
Dec 17 20:28:10.253 INFO [stderr] 
Dec 17 20:28:10.253 INFO [stderr] warning: function is never used: `diverges`
Dec 17 20:28:10.253 INFO [stderr]    --> src/main.rs:140:1
Dec 17 20:28:10.253 INFO [stderr]     |
Dec 17 20:28:10.253 INFO [stderr] 140 | fn diverges() -> ! {                            // defines the return type as "diverges" using the bang symbol
Dec 17 20:28:10.253 INFO [stderr]     | ^^^^^^^^^^^^^^^^^^
Dec 17 20:28:10.253 INFO [stderr]     |
Dec 17 20:28:10.253 INFO [stderr]     = note: #[warn(dead_code)] on by default
Dec 17 20:28:10.253 INFO [stderr] 
Dec 17 20:28:10.299 INFO [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.62s
Dec 17 20:28:11.071 INFO running `"docker" "inspect" "87a2a4eccad084d5a9980c4fb3d8129e81d892abaa4bd9c608b0dee0161b2758"`
Dec 17 20:28:11.383 INFO running `"docker" "rm" "-f" "87a2a4eccad084d5a9980c4fb3d8129e81d892abaa4bd9c608b0dee0161b2758"`
Dec 17 20:28:11.722 INFO [stdout] 87a2a4eccad084d5a9980c4fb3d8129e81d892abaa4bd9c608b0dee0161b2758