[INFO] updating cached repository https://github.com/fitzgen/rust-words
[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] 7e230a7414ad9761ed39b02d220bb94b99ad81db
[INFO] checking fitzgen/rust-words against master#bf1f2eedda4fa02b7c9347dd849ed73ddd43dedc for pr-70917
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffitzgen%2Frust-words" "/workspace/builds/worker-12/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/fitzgen/rust-words 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/fitzgen/rust-words
[INFO] finished tweaking git repo https://github.com/fitzgen/rust-words
[INFO] tweaked toml for git repo https://github.com/fitzgen/rust-words written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate git repo https://github.com/fitzgen/rust-words already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+bf1f2eedda4fa02b7c9347dd849ed73ddd43dedc" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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] 585f0eae2d0b33190448eb36015a1f5b1ec17b5bdb1d4fc7d500d2cac47ce914
[INFO] running `"docker" "start" "-a" "585f0eae2d0b33190448eb36015a1f5b1ec17b5bdb1d4fc7d500d2cac47ce914"`
[INFO] [stderr]     Checking words v0.0.1 (/opt/rustwide/workdir)
[INFO] [stderr] error: invalid suffix `u` for integer literal
[INFO] [stderr]   --> src/main.rs:10:50
[INFO] [stderr]    |
[INFO] [stderr] 10 |             |words, w| words.insert_or_modify(w, 1u, &mut |v| v + 1)
[INFO] [stderr]    |                                                  ^^ invalid suffix `u`
[INFO] [stderr]    |
[INFO] [stderr]    = help: the suffix must be one of the integral types (`u32`, `isize`, etc)
[INFO] [stderr] 
[INFO] [stderr] error: invalid suffix `u` for integer literal
[INFO] [stderr]   --> src/main.rs:10:50
[INFO] [stderr]    |
[INFO] [stderr] 10 |             |words, w| words.insert_or_modify(w, 1u, &mut |v| v + 1)
[INFO] [stderr]    |                                                  ^^ invalid suffix `u`
[INFO] [stderr]    |
[INFO] [stderr]    = help: the suffix must be one of the integral types (`u32`, `isize`, etc)
[INFO] [stderr] 
[INFO] [stderr] error: expected type, found `|`
[INFO] [stderr]   --> src/my_tree.rs:24:60
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn insert_or_modify(self, k: K, v: V, modify: &mut |V| -> V) -> Tree<K, V> {
[INFO] [stderr]    |                                                            ^ expected type
[INFO] [stderr] 
[INFO] [stderr] error: expected type, found `|`
[INFO] [stderr]   --> src/my_tree.rs:58:32
[INFO] [stderr]    |
[INFO] [stderr] 58 |     pub fn each(&self, f: &mut |&K, &V|) {
[INFO] [stderr]    |                                ^ expected type
[INFO] [stderr] 
[INFO] [stderr] error: a trailing `|` is not allowed in an or-pattern
[INFO] [stderr]   --> src/my_tree.rs:58:39
[INFO] [stderr]    |
[INFO] [stderr] 58 |     pub fn each(&self, f: &mut |&K, &V|) {
[INFO] [stderr]    |                                     --^ help: remove the `|`
[INFO] [stderr]    |                                     |
[INFO] [stderr]    |                                     while parsing this or-pattern starting here
[INFO] [stderr] 
[INFO] [stderr] error: an or-pattern parameter must be wrapped in parenthesis
[INFO] [stderr]   --> src/my_tree.rs:58:37
[INFO] [stderr]    |
[INFO] [stderr] 58 |     pub fn each(&self, f: &mut |&K, &V|) {
[INFO] [stderr]    |                                     ^^^ help: wrap the pattern in parenthesis: `(&V)`
[INFO] [stderr] 
[INFO] [stderr] error: expected `:`, found `)`
[INFO] [stderr]   --> src/my_tree.rs:58:40
[INFO] [stderr]    |
[INFO] [stderr] 58 |     pub fn each(&self, f: &mut |&K, &V|) {
[INFO] [stderr]    |                                        ^ expected `:`
[INFO] [stderr] 
[INFO] [stderr] error: expected type, found `|`
[INFO] [stderr]   --> src/my_tree.rs:73:32
[INFO] [stderr]    |
[INFO] [stderr] 73 |     let mut assert_no_modify : |uint| -> uint = |_| { assert!(false); 0u };
[INFO] [stderr]    |         --------------------   ^ expected type
[INFO] [stderr]    |         |
[INFO] [stderr]    |         while parsing the type for `mut assert_no_modify`
[INFO] [stderr] 
[INFO] [stderr] error: expected type, found `|`
[INFO] [stderr]   --> src/my_tree.rs:93:32
[INFO] [stderr]    |
[INFO] [stderr] 93 |     let mut assert_no_modify : |uint| -> uint = |_| { assert!(false); 0u };
[INFO] [stderr]    |         --------------------   ^ expected type
[INFO] [stderr]    |         |
[INFO] [stderr]    |         while parsing the type for `mut assert_no_modify`
[INFO] [stderr] 
[INFO] [stderr] error: invalid suffix `u` for integer literal
[INFO] [stderr]   --> src/word_reader.rs:61:25
[INFO] [stderr]    |
[INFO] [stderr] 61 |         if word.len() > 0u  { Some(word) } else { None }
[INFO] [stderr]    |                         ^^ invalid suffix `u`
[INFO] [stderr]    |
[INFO] [stderr]    = help: the suffix must be one of the integral types (`u32`, `isize`, etc)
[INFO] [stderr] 
[INFO] [stderr] error: expected type, found `|`
[INFO] [stderr]   --> src/my_tree.rs:24:60
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn insert_or_modify(self, k: K, v: V, modify: &mut |V| -> V) -> Tree<K, V> {
[INFO] [stderr]    |                                                            ^ expected type
[INFO] [stderr] 
[INFO] [stderr] error: expected type, found `|`
[INFO] [stderr]   --> src/my_tree.rs:58:32
[INFO] [stderr]    |
[INFO] [stderr] 58 |     pub fn each(&self, f: &mut |&K, &V|) {
[INFO] [stderr]    |                                ^ expected type
[INFO] [stderr] 
[INFO] [stderr] error: a trailing `|` is not allowed in an or-pattern
[INFO] [stderr]   --> src/my_tree.rs:58:39
[INFO] [stderr]    |
[INFO] [stderr] 58 |     pub fn each(&self, f: &mut |&K, &V|) {
[INFO] [stderr]    |                                     --^ help: remove the `|`
[INFO] [stderr]    |                                     |
[INFO] [stderr]    |                                     while parsing this or-pattern starting here
[INFO] [stderr] 
[INFO] [stderr] error: an or-pattern parameter must be wrapped in parenthesis
[INFO] [stderr]   --> src/my_tree.rs:58:37
[INFO] [stderr]    |
[INFO] [stderr] 58 |     pub fn each(&self, f: &mut |&K, &V|) {
[INFO] [stderr]    |                                     ^^^ help: wrap the pattern in parenthesis: `(&V)`
[INFO] [stderr] 
[INFO] [stderr] error: expected `:`, found `)`
[INFO] [stderr]   --> src/my_tree.rs:58:40
[INFO] [stderr]    |
[INFO] [stderr] 58 |     pub fn each(&self, f: &mut |&K, &V|) {
[INFO] [stderr]    |                                        ^ expected `:`
[INFO] [stderr] 
[INFO] [stderr] error: expected type, found `|`
[INFO] [stderr]   --> src/my_tree.rs:73:32
[INFO] [stderr]    |
[INFO] [stderr] 73 |     let mut assert_no_modify : |uint| -> uint = |_| { assert!(false); 0u };
[INFO] [stderr]    |         --------------------   ^ expected type
[INFO] [stderr]    |         |
[INFO] [stderr]    |         while parsing the type for `mut assert_no_modify`
[INFO] [stderr] 
[INFO] [stderr] error: expected type, found `|`
[INFO] [stderr]   --> src/my_tree.rs:93:32
[INFO] [stderr]    |
[INFO] [stderr] 93 |     let mut assert_no_modify : |uint| -> uint = |_| { assert!(false); 0u };
[INFO] [stderr]    |         --------------------   ^ expected type
[INFO] [stderr]    |         |
[INFO] [stderr]    |         while parsing the type for `mut assert_no_modify`
[INFO] [stderr] 
[INFO] [stderr] error: invalid suffix `u` for integer literal
[INFO] [stderr]   --> src/word_reader.rs:61:25
[INFO] [stderr]    |
[INFO] [stderr] 61 |         if word.len() > 0u  { Some(word) } else { None }
[INFO] [stderr]    |                         ^^ invalid suffix `u`
[INFO] [stderr]    |
[INFO] [stderr]    = help: the suffix must be one of the integral types (`u32`, `isize`, etc)
[INFO] [stderr] 
[INFO] [stderr] error[E0432]: unresolved import `std::io::IoErrorKind`
[INFO] [stderr]  --> src/word_reader.rs:3:5
[INFO] [stderr]   |
[INFO] [stderr] 3 | use std::io::IoErrorKind;
[INFO] [stderr]   |     ^^^^^^^^^-----------
[INFO] [stderr]   |     |        |
[INFO] [stderr]   |     |        help: a similar name exists in the module: `ErrorKind`
[INFO] [stderr]   |     no `IoErrorKind` in `io`
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `modify` in this scope
[INFO] [stderr]   --> src/my_tree.rs:34:52
[INFO] [stderr]    |
[INFO] [stderr] 34 | ...                   value: (*modify)(value),
[INFO] [stderr]    |                                ^^^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `modify` in this scope
[INFO] [stderr]   --> src/my_tree.rs:40:80
[INFO] [stderr]    |
[INFO] [stderr] 40 | ...                   left: box left.insert_or_modify(k, v, modify),
[INFO] [stderr]    |                                                             ^^^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `modify` in this scope
[INFO] [stderr]   --> src/my_tree.rs:46:85
[INFO] [stderr]    |
[INFO] [stderr] 46 | ...                   right: box right.insert_or_modify(k, v, modify)
[INFO] [stderr]    |                                                               ^^^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `f` in this scope
[INFO] [stderr]   --> src/my_tree.rs:62:27
[INFO] [stderr]    |
[INFO] [stderr] 62 |                 left.each(f);
[INFO] [stderr]    |                           ^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `f` in this scope
[INFO] [stderr]   --> src/my_tree.rs:63:19
[INFO] [stderr]    |
[INFO] [stderr] 63 |                 (*f)(key, value);
[INFO] [stderr]    |                   ^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `f` in this scope
[INFO] [stderr]   --> src/my_tree.rs:64:28
[INFO] [stderr]    |
[INFO] [stderr] 64 |                 right.each(f);
[INFO] [stderr]    |                            ^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0412]: cannot find type `uint` in this scope
[INFO] [stderr]   --> src/my_tree.rs:72:25
[INFO] [stderr]    |
[INFO] [stderr] 71 | fn iterate_over_inserted_items_in_order() {
[INFO] [stderr]    |                                        - help: you might be missing a type parameter: `<uint>`
[INFO] [stderr] 72 |     let mut tree : Tree<uint, uint> = Tree::new();
[INFO] [stderr]    |                         ^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0412]: cannot find type `uint` in this scope
[INFO] [stderr]   --> src/my_tree.rs:72:31
[INFO] [stderr]    |
[INFO] [stderr] 71 | fn iterate_over_inserted_items_in_order() {
[INFO] [stderr]    |                                        - help: you might be missing a type parameter: `<uint>`
[INFO] [stderr] 72 |     let mut tree : Tree<uint, uint> = Tree::new();
[INFO] [stderr]    |                               ^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0412]: cannot find type `uint` in this scope
[INFO] [stderr]   --> src/my_tree.rs:92:25
[INFO] [stderr]    |
[INFO] [stderr] 91 | fn modify_inserted_items() {
[INFO] [stderr]    |                         - help: you might be missing a type parameter: `<uint>`
[INFO] [stderr] 92 |     let mut tree : Tree<uint, uint> = Tree::new();
[INFO] [stderr]    |                         ^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0412]: cannot find type `uint` in this scope
[INFO] [stderr]   --> src/my_tree.rs:92:31
[INFO] [stderr]    |
[INFO] [stderr] 91 | fn modify_inserted_items() {
[INFO] [stderr]    |                         - help: you might be missing a type parameter: `<uint>`
[INFO] [stderr] 92 |     let mut tree : Tree<uint, uint> = Tree::new();
[INFO] [stderr]    |                               ^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0412]: cannot find type `IoError` in module `io`
[INFO] [stderr]   --> src/word_reader.rs:16:22
[INFO] [stderr]    |
[INFO] [stderr] 16 |   fn is_eof(err : &io::IoError) -> bool {
[INFO] [stderr]    |                        ^^^^^^^ help: a struct with a similar name exists: `Error`
[INFO] [stderr] 
[INFO] [stderr] error[E0412]: cannot find type `uint` in this scope
[INFO] [stderr]  --> src/main.rs:7:39
[INFO] [stderr]   |
[INFO] [stderr] 7 |     let words : my_tree::Tree<String, uint> =
[INFO] [stderr]   |                                       ^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0412]: cannot find type `uint` in this scope
[INFO] [stderr]   --> src/main.rs:13:41
[INFO] [stderr]    |
[INFO] [stderr] 13 |     words.each(&mut |word: &String, n: &uint| {
[INFO] [stderr]    |                                         ^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0603]: module `stdio` is private
[INFO] [stderr]    --> src/word_reader.rs:2:14
[INFO] [stderr]     |
[INFO] [stderr] 2   | use std::io::stdio;
[INFO] [stderr]     |              ^^^^^ private module
[INFO] [stderr]     |
[INFO] [stderr] note: the module `stdio` is defined here
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: box expression syntax is experimental; you can call `Box::new` instead
[INFO] [stderr]   --> src/my_tree.rs:28:46
[INFO] [stderr]    |
[INFO] [stderr] 28 | ...                   left: box Tree::Null,
[INFO] [stderr]    |                             ^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: see issue #49733 <https://github.com/rust-lang/rust/issues/49733> for more information
[INFO] [stderr]    = help: add `#![feature(box_syntax)]` to the crate attributes to enable
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: box expression syntax is experimental; you can call `Box::new` instead
[INFO] [stderr]   --> src/my_tree.rs:29:47
[INFO] [stderr]    |
[INFO] [stderr] 29 | ...                   right: box Tree::Null
[INFO] [stderr]    |                              ^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: see issue #49733 <https://github.com/rust-lang/rust/issues/49733> for more information
[INFO] [stderr]    = help: add `#![feature(box_syntax)]` to the crate attributes to enable
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: box expression syntax is experimental; you can call `Box::new` instead
[INFO] [stderr]   --> src/my_tree.rs:40:48
[INFO] [stderr]    |
[INFO] [stderr] 40 | ...                   left: box left.insert_or_modify(k, v, modify),
[INFO] [stderr]    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: see issue #49733 <https://github.com/rust-lang/rust/issues/49733> for more information
[INFO] [stderr]    = help: add `#![feature(box_syntax)]` to the crate attributes to enable
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: box expression syntax is experimental; you can call `Box::new` instead
[INFO] [stderr]   --> src/my_tree.rs:46:52
[INFO] [stderr]    |
[INFO] [stderr] 46 | ...                   right: box right.insert_or_modify(k, v, modify)
[INFO] [stderr]    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: see issue #49733 <https://github.com/rust-lang/rust/issues/49733> for more information
[INFO] [stderr]    = help: add `#![feature(box_syntax)]` to the crate attributes to enable
[INFO] [stderr] 
[INFO] [stderr] error[E0107]: wrong number of type arguments: expected 0, found 1
[INFO] [stderr]   --> src/word_reader.rs:37:15
[INFO] [stderr]    |
[INFO] [stderr] 37 | impl Iterator<String> for WordReader {
[INFO] [stderr]    |               ^^^^^^ unexpected type argument
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 29 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0107, E0412, E0425, E0432, E0603, E0658.
[INFO] [stderr] For more information about an error, try `rustc --explain E0107`.
[INFO] [stderr] error: could not compile `words`.
[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] error[E0432]: unresolved import `std::io::IoErrorKind`
[INFO] [stderr]  --> src/word_reader.rs:3:5
[INFO] [stderr]   |
[INFO] [stderr] 3 | use std::io::IoErrorKind;
[INFO] [stderr]   |     ^^^^^^^^^-----------
[INFO] [stderr]   |     |        |
[INFO] [stderr]   |     |        help: a similar name exists in the module: `ErrorKind`
[INFO] [stderr]   |     no `IoErrorKind` in `io`
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `modify` in this scope
[INFO] [stderr]   --> src/my_tree.rs:34:52
[INFO] [stderr]    |
[INFO] [stderr] 34 | ...                   value: (*modify)(value),
[INFO] [stderr]    |                                ^^^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `modify` in this scope
[INFO] [stderr]   --> src/my_tree.rs:40:80
[INFO] [stderr]    |
[INFO] [stderr] 40 | ...                   left: box left.insert_or_modify(k, v, modify),
[INFO] [stderr]    |                                                             ^^^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `modify` in this scope
[INFO] [stderr]   --> src/my_tree.rs:46:85
[INFO] [stderr]    |
[INFO] [stderr] 46 | ...                   right: box right.insert_or_modify(k, v, modify)
[INFO] [stderr]    |                                                               ^^^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `f` in this scope
[INFO] [stderr]   --> src/my_tree.rs:62:27
[INFO] [stderr]    |
[INFO] [stderr] 62 |                 left.each(f);
[INFO] [stderr]    |                           ^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `f` in this scope
[INFO] [stderr]   --> src/my_tree.rs:63:19
[INFO] [stderr]    |
[INFO] [stderr] 63 |                 (*f)(key, value);
[INFO] [stderr]    |                   ^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0425]: cannot find value `f` in this scope
[INFO] [stderr]   --> src/my_tree.rs:64:28
[INFO] [stderr]    |
[INFO] [stderr] 64 |                 right.each(f);
[INFO] [stderr]    |                            ^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0412]: cannot find type `IoError` in module `io`
[INFO] [stderr]   --> src/word_reader.rs:16:22
[INFO] [stderr]    |
[INFO] [stderr] 16 |   fn is_eof(err : &io::IoError) -> bool {
[INFO] [stderr]    |                        ^^^^^^^ help: a struct with a similar name exists: `Error`
[INFO] [stderr] 
[INFO] [stderr] error[E0412]: cannot find type `uint` in this scope
[INFO] [stderr]  --> src/main.rs:7:39
[INFO] [stderr]   |
[INFO] [stderr] 7 |     let words : my_tree::Tree<String, uint> =
[INFO] [stderr]   |                                       ^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0412]: cannot find type `uint` in this scope
[INFO] [stderr]   --> src/main.rs:13:41
[INFO] [stderr]    |
[INFO] [stderr] 13 |     words.each(&mut |word: &String, n: &uint| {
[INFO] [stderr]    |                                         ^^^^ not found in this scope
[INFO] [stderr] 
[INFO] [stderr] error[E0603]: module `stdio` is private
[INFO] [stderr]    --> src/word_reader.rs:2:14
[INFO] [stderr]     |
[INFO] [stderr] 2   | use std::io::stdio;
[INFO] [stderr]     |              ^^^^^ private module
[INFO] [stderr]     |
[INFO] [stderr] note: the module `stdio` is defined here
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: box expression syntax is experimental; you can call `Box::new` instead
[INFO] [stderr]   --> src/my_tree.rs:28:46
[INFO] [stderr]    |
[INFO] [stderr] 28 | ...                   left: box Tree::Null,
[INFO] [stderr]    |                             ^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: see issue #49733 <https://github.com/rust-lang/rust/issues/49733> for more information
[INFO] [stderr]    = help: add `#![feature(box_syntax)]` to the crate attributes to enable
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: box expression syntax is experimental; you can call `Box::new` instead
[INFO] [stderr]   --> src/my_tree.rs:29:47
[INFO] [stderr]    |
[INFO] [stderr] 29 | ...                   right: box Tree::Null
[INFO] [stderr]    |                              ^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: see issue #49733 <https://github.com/rust-lang/rust/issues/49733> for more information
[INFO] [stderr]    = help: add `#![feature(box_syntax)]` to the crate attributes to enable
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: box expression syntax is experimental; you can call `Box::new` instead
[INFO] [stderr]   --> src/my_tree.rs:40:48
[INFO] [stderr]    |
[INFO] [stderr] 40 | ...                   left: box left.insert_or_modify(k, v, modify),
[INFO] [stderr]    |                             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: see issue #49733 <https://github.com/rust-lang/rust/issues/49733> for more information
[INFO] [stderr]    = help: add `#![feature(box_syntax)]` to the crate attributes to enable
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: box expression syntax is experimental; you can call `Box::new` instead
[INFO] [stderr]   --> src/my_tree.rs:46:52
[INFO] [stderr]    |
[INFO] [stderr] 46 | ...                   right: box right.insert_or_modify(k, v, modify)
[INFO] [stderr]    |                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: see issue #49733 <https://github.com/rust-lang/rust/issues/49733> for more information
[INFO] [stderr]    = help: add `#![feature(box_syntax)]` to the crate attributes to enable
[INFO] [stderr] 
[INFO] [stderr] error[E0107]: wrong number of type arguments: expected 0, found 1
[INFO] [stderr]   --> src/word_reader.rs:37:15
[INFO] [stderr]    |
[INFO] [stderr] 37 | impl Iterator<String> for WordReader {
[INFO] [stderr]    |               ^^^^^^ unexpected type argument
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 25 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0107, E0412, E0425, E0432, E0603, E0658.
[INFO] [stderr] For more information about an error, try `rustc --explain E0107`.
[INFO] [stderr] error: could not compile `words`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "585f0eae2d0b33190448eb36015a1f5b1ec17b5bdb1d4fc7d500d2cac47ce914"`
[INFO] running `"docker" "rm" "-f" "585f0eae2d0b33190448eb36015a1f5b1ec17b5bdb1d4fc7d500d2cac47ce914"`
[INFO] [stdout] 585f0eae2d0b33190448eb36015a1f5b1ec17b5bdb1d4fc7d500d2cac47ce914
