[INFO] cloning repository https://github.com/captainbland/tree-climber
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/captainbland/tree-climber" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcaptainbland%2Ftree-climber", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcaptainbland%2Ftree-climber'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d42c596f40b568d7428a2abb18ae1763206d117b
[INFO] checking captainbland/tree-climber against try#4a23c45c7893f1416456144e3883cc48ea91722e for pr-82322
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fcaptainbland%2Ftree-climber" "/workspace/builds/worker-2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/captainbland/tree-climber on toolchain 4a23c45c7893f1416456144e3883cc48ea91722e
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4a23c45c7893f1416456144e3883cc48ea91722e" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/captainbland/tree-climber
[INFO] finished tweaking git repo https://github.com/captainbland/tree-climber
[INFO] tweaked toml for git repo https://github.com/captainbland/tree-climber written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/captainbland/tree-climber already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4a23c45c7893f1416456144e3883cc48ea91722e" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded generational-arena v0.2.3
[INFO] [stderr]   Downloaded vec-tree v0.1.2
[INFO] [stderr]   Downloaded libc v0.2.64
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:f2f6bcd4b43ebee4e173f653a26493129bdb64017c85f916b780ca7fbdbaa79d" "/opt/rustwide/cargo-home/bin/cargo" "+4a23c45c7893f1416456144e3883cc48ea91722e" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8d3919d6a7b1528d6de13287b9276c921b6af3a6d978601bd2b91d2b8b29395d
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "8d3919d6a7b1528d6de13287b9276c921b6af3a6d978601bd2b91d2b8b29395d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8d3919d6a7b1528d6de13287b9276c921b6af3a6d978601bd2b91d2b8b29395d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8d3919d6a7b1528d6de13287b9276c921b6af3a6d978601bd2b91d2b8b29395d", kill_on_drop: false }`
[INFO] [stdout] 8d3919d6a7b1528d6de13287b9276c921b6af3a6d978601bd2b91d2b8b29395d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "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" "--user" "0:0" "--network" "none" "rustops/crates-build-env@sha256:f2f6bcd4b43ebee4e173f653a26493129bdb64017c85f916b780ca7fbdbaa79d" "/opt/rustwide/cargo-home/bin/cargo" "+4a23c45c7893f1416456144e3883cc48ea91722e" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 7db89f13ebba3ec004e2100d783d7c7c7c6a5dfc52d38000027de1d281dd4d33
[INFO] running `Command { std: "docker" "start" "-a" "7db89f13ebba3ec004e2100d783d7c7c7c6a5dfc52d38000027de1d281dd4d33", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.64
[INFO] [stderr]     Checking cfg-if v0.1.10
[INFO] [stderr]     Checking unicode-width v0.1.6
[INFO] [stderr]     Checking vec_map v0.8.1
[INFO] [stderr]     Checking unicode-segmentation v1.3.0
[INFO] [stderr]     Checking thread_local v0.3.6
[INFO] [stderr]     Checking generational-arena v0.2.3
[INFO] [stderr]     Checking textwrap v0.11.0
[INFO] [stderr]     Checking regex v1.3.1
[INFO] [stderr]     Checking vec-tree v0.1.2
[INFO] [stderr]     Checking atty v0.2.13
[INFO] [stderr]     Checking clap v2.33.0
[INFO] [stderr]     Checking climb v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0463]: can't find crate for `climb`
[INFO] [stdout]  --> tests/test.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | extern crate climb;
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^ can't find crate
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0463`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `climb`
[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] [stdout] error[E0425]: cannot find value `main_child` in this scope
[INFO] [stdout]    --> src/climb/tree_tools.rs:192:25
[INFO] [stdout]     |
[INFO] [stdout] 192 |             stack.push((main_child, insert_child));
[INFO] [stdout]     |                         ^^^^^^^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/main.rs:6:1
[INFO] [stdout]   |
[INFO] [stdout] 6 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::fmt`
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 | use core::fmt;
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Error`, `Formatter`
[INFO] [stdout]   --> src/main.rs:11:16
[INFO] [stdout]    |
[INFO] [stdout] 11 | use std::fmt::{Error, Formatter};
[INFO] [stdout]    |                ^^^^^  ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `unicode_segmentation::UnicodeSegmentation`
[INFO] [stdout]   --> src/main.rs:13:5
[INFO] [stdout]    |
[INFO] [stdout] 13 | use unicode_segmentation::UnicodeSegmentation;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `vec_tree::*`
[INFO] [stdout]   --> src/main.rs:14:5
[INFO] [stdout]    |
[INFO] [stdout] 14 | use vec_tree::*;
[INFO] [stdout]    |     ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::fmt`
[INFO] [stdout]  --> src/climb/mod.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use core::fmt;
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Error`, `Formatter`
[INFO] [stdout]  --> src/climb/mod.rs:3:16
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::fmt::{Error, Formatter};
[INFO] [stdout]   |                ^^^^^  ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `io::Read`, `io`
[INFO] [stdout]  --> src/climb/mod.rs:4:11
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::{io, io::Read};
[INFO] [stdout]   |           ^^  ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `crate::climb::print_tree`
[INFO] [stdout]  --> src/climb/tree_tools.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use crate::climb::print_tree;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `BTreeSet`, `HashSet`
[INFO] [stdout]  --> src/climb/tree_tools.rs:4:24
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::collections::{BTreeSet, HashSet};
[INFO] [stdout]   |                        ^^^^^^^^  ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `error`, `io`
[INFO] [stdout]  --> src/climb/tree_tools.rs:5:11
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::{error, io};
[INFO] [stdout]   |           ^^^^^  ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused macro definition
[INFO] [stdout]   --> src/climb/tree_tools.rs:8:1
[INFO] [stdout]    |
[INFO] [stdout] 8  | / macro_rules! wrap_str_err {
[INFO] [stdout] 9  | |     ($st: expr) => {
[INFO] [stdout] 10 | |         $st.map_err(|e| format!("{}", e))?
[INFO] [stdout] 11 | |     };
[INFO] [stdout] 12 | | }
[INFO] [stdout]    | |_^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_macros)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `tree_tools::get_ancestors_match_re`
[INFO] [stdout]   --> src/climb/mod.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | use tree_tools::get_ancestors_match_re;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `main_child` in this scope
[INFO] [stdout]    --> src/climb/tree_tools.rs:192:25
[INFO] [stdout]     |
[INFO] [stdout] 192 |             stack.push((main_child, insert_child));
[INFO] [stdout]     |                         ^^^^^^^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `#[macro_use]` import
[INFO] [stdout]  --> src/main.rs:6:1
[INFO] [stdout]   |
[INFO] [stdout] 6 | #[macro_use]
[INFO] [stdout]   | ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::fmt`
[INFO] [stdout]  --> src/main.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 | use core::fmt;
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Error`, `Formatter`
[INFO] [stdout]   --> src/main.rs:11:16
[INFO] [stdout]    |
[INFO] [stdout] 11 | use std::fmt::{Error, Formatter};
[INFO] [stdout]    |                ^^^^^  ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `unicode_segmentation::UnicodeSegmentation`
[INFO] [stdout]   --> src/main.rs:13:5
[INFO] [stdout]    |
[INFO] [stdout] 13 | use unicode_segmentation::UnicodeSegmentation;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `vec_tree::*`
[INFO] [stdout]   --> src/main.rs:14:5
[INFO] [stdout]    |
[INFO] [stdout] 14 | use vec_tree::*;
[INFO] [stdout]    |     ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `core::fmt`
[INFO] [stdout]  --> src/climb/mod.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use core::fmt;
[INFO] [stdout]   |     ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `Error`, `Formatter`
[INFO] [stdout]  --> src/climb/mod.rs:3:16
[INFO] [stdout]   |
[INFO] [stdout] 3 | use std::fmt::{Error, Formatter};
[INFO] [stdout]   |                ^^^^^  ^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `io::Read`, `io`
[INFO] [stdout]  --> src/climb/mod.rs:4:11
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::{io, io::Read};
[INFO] [stdout]   |           ^^  ^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `crate::climb::print_tree`
[INFO] [stdout]  --> src/climb/tree_tools.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use crate::climb::print_tree;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `BTreeSet`, `HashSet`
[INFO] [stdout]  --> src/climb/tree_tools.rs:4:24
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::collections::{BTreeSet, HashSet};
[INFO] [stdout]   |                        ^^^^^^^^  ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused imports: `error`, `io`
[INFO] [stdout]  --> src/climb/tree_tools.rs:5:11
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::{error, io};
[INFO] [stdout]   |           ^^^^^  ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused macro definition
[INFO] [stdout]   --> src/climb/tree_tools.rs:8:1
[INFO] [stdout]    |
[INFO] [stdout] 8  | / macro_rules! wrap_str_err {
[INFO] [stdout] 9  | |     ($st: expr) => {
[INFO] [stdout] 10 | |         $st.map_err(|e| format!("{}", e))?
[INFO] [stdout] 11 | |     };
[INFO] [stdout] 12 | | }
[INFO] [stdout]    | |_^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_macros)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `tree_tools::get_ancestors_match_re`
[INFO] [stdout]   --> src/climb/mod.rs:11:5
[INFO] [stdout]    |
[INFO] [stdout] 11 | use tree_tools::get_ancestors_match_re;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> src/climb/tree_tools.rs:22:16
[INFO] [stdout]    |
[INFO] [stdout] 18 | / pub fn get_ancestors_match_re(
[INFO] [stdout] 19 | |     tree: &VecTree<String>,
[INFO] [stdout] 20 | |     regex: Regex,
[INFO] [stdout] 21 | | ) -> Result<VecTree<String>, ProcessingError> {
[INFO] [stdout] 22 | |     let root = tree.get_root_index()?;
[INFO] [stdout]    | |                ^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<vec_tree::VecTree<String>, ProcessingError>`
[INFO] [stdout] ...  |
[INFO] [stdout] 34 | |     return Ok(out_tree);
[INFO] [stdout] 35 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<vec_tree::VecTree<String>, ProcessingError>`
[INFO] [stdout]    = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> src/climb/tree_tools.rs:22:16
[INFO] [stdout]    |
[INFO] [stdout] 18 | / pub fn get_ancestors_match_re(
[INFO] [stdout] 19 | |     tree: &VecTree<String>,
[INFO] [stdout] 20 | |     regex: Regex,
[INFO] [stdout] 21 | | ) -> Result<VecTree<String>, ProcessingError> {
[INFO] [stdout] 22 | |     let root = tree.get_root_index()?;
[INFO] [stdout]    | |                ^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<vec_tree::VecTree<String>, ProcessingError>`
[INFO] [stdout] ...  |
[INFO] [stdout] 34 | |     return Ok(out_tree);
[INFO] [stdout] 35 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<vec_tree::VecTree<String>, ProcessingError>`
[INFO] [stdout]    = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> src/climb/tree_tools.rs:49:22
[INFO] [stdout]    |
[INFO] [stdout] 37 | / fn accumulate_ancestors(
[INFO] [stdout] 38 | |     tree: &VecTree<String>,
[INFO] [stdout] 39 | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 40 | |     matching_descendant: Index,
[INFO] [stdout] ...  |
[INFO] [stdout] 49 | |     let mut parent = out_tree.get_root_index()?;
[INFO] [stdout]    | |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...  |
[INFO] [stdout] 65 | |     Ok(())
[INFO] [stdout] 66 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]    = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> src/climb/tree_tools.rs:49:22
[INFO] [stdout]    |
[INFO] [stdout] 37 | / fn accumulate_ancestors(
[INFO] [stdout] 38 | |     tree: &VecTree<String>,
[INFO] [stdout] 39 | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 40 | |     matching_descendant: Index,
[INFO] [stdout] ...  |
[INFO] [stdout] 49 | |     let mut parent = out_tree.get_root_index()?;
[INFO] [stdout]    | |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...  |
[INFO] [stdout] 65 | |     Ok(())
[INFO] [stdout] 66 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]    = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> src/climb/tree_tools.rs:51:40
[INFO] [stdout]    |
[INFO] [stdout] 37 | / fn accumulate_ancestors(
[INFO] [stdout] 38 | |     tree: &VecTree<String>,
[INFO] [stdout] 39 | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 40 | |     matching_descendant: Index,
[INFO] [stdout] ...  |
[INFO] [stdout] 51 | |         let descendent_ancestor_data = tree.get(descendant_ancestor)?.to_owned();
[INFO] [stdout]    | |                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...  |
[INFO] [stdout] 65 | |     Ok(())
[INFO] [stdout] 66 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]    = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> src/climb/tree_tools.rs:51:40
[INFO] [stdout]    |
[INFO] [stdout] 37 | / fn accumulate_ancestors(
[INFO] [stdout] 38 | |     tree: &VecTree<String>,
[INFO] [stdout] 39 | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 40 | |     matching_descendant: Index,
[INFO] [stdout] ...  |
[INFO] [stdout] 51 | |         let descendent_ancestor_data = tree.get(descendant_ancestor)?.to_owned();
[INFO] [stdout]    | |                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...  |
[INFO] [stdout] 65 | |     Ok(())
[INFO] [stdout] 66 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]    = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> src/climb/tree_tools.rs:56:16
[INFO] [stdout]    |
[INFO] [stdout] 37 | / fn accumulate_ancestors(
[INFO] [stdout] 38 | |     tree: &VecTree<String>,
[INFO] [stdout] 39 | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 40 | |     matching_descendant: Index,
[INFO] [stdout] ...  |
[INFO] [stdout] 56 | |             if out_tree.get(out_child)?.clone() == descendent_ancestor_data {
[INFO] [stdout]    | |                ^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...  |
[INFO] [stdout] 65 | |     Ok(())
[INFO] [stdout] 66 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]    = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]   --> src/climb/tree_tools.rs:56:16
[INFO] [stdout]    |
[INFO] [stdout] 37 | / fn accumulate_ancestors(
[INFO] [stdout] 38 | |     tree: &VecTree<String>,
[INFO] [stdout] 39 | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 40 | |     matching_descendant: Index,
[INFO] [stdout] ...  |
[INFO] [stdout] 56 | |             if out_tree.get(out_child)?.clone() == descendent_ancestor_data {
[INFO] [stdout]    | |                ^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...  |
[INFO] [stdout] 65 | |     Ok(())
[INFO] [stdout] 66 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]    = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:97:35
[INFO] [stdout]     |
[INFO] [stdout] 89  | / fn accumulate_descendants(
[INFO] [stdout] 90  | |     tree: &VecTree<String>,
[INFO] [stdout] 91  | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 92  | |     root_node: Index,
[INFO] [stdout] ...   |
[INFO] [stdout] 97  | |     let matching_descendant_str = tree.get(matching_descendant)?.clone();
[INFO] [stdout]     | |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 109 | |     Ok(())
[INFO] [stdout] 110 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:97:35
[INFO] [stdout]     |
[INFO] [stdout] 89  | / fn accumulate_descendants(
[INFO] [stdout] 90  | |     tree: &VecTree<String>,
[INFO] [stdout] 91  | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 92  | |     root_node: Index,
[INFO] [stdout] ...   |
[INFO] [stdout] 97  | |     let matching_descendant_str = tree.get(matching_descendant)?.clone();
[INFO] [stdout]     | |                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 109 | |     Ok(())
[INFO] [stdout] 110 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:101:39
[INFO] [stdout]     |
[INFO] [stdout] 89  | / fn accumulate_descendants(
[INFO] [stdout] 90  | |     tree: &VecTree<String>,
[INFO] [stdout] 91  | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 92  | |     root_node: Index,
[INFO] [stdout] ...   |
[INFO] [stdout] 101 | |         let (in_parent, out_parent) = stack.pop()?;
[INFO] [stdout]     | |                                       ^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 109 | |     Ok(())
[INFO] [stdout] 110 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:101:39
[INFO] [stdout]     |
[INFO] [stdout] 89  | / fn accumulate_descendants(
[INFO] [stdout] 90  | |     tree: &VecTree<String>,
[INFO] [stdout] 91  | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 92  | |     root_node: Index,
[INFO] [stdout] ...   |
[INFO] [stdout] 101 | |         let (in_parent, out_parent) = stack.pop()?;
[INFO] [stdout]     | |                                       ^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 109 | |     Ok(())
[INFO] [stdout] 110 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:103:30
[INFO] [stdout]     |
[INFO] [stdout] 89  | / fn accumulate_descendants(
[INFO] [stdout] 90  | |     tree: &VecTree<String>,
[INFO] [stdout] 91  | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 92  | |     root_node: Index,
[INFO] [stdout] ...   |
[INFO] [stdout] 103 | |             let child_data = tree.get(child)?.clone();
[INFO] [stdout]     | |                              ^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 109 | |     Ok(())
[INFO] [stdout] 110 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:103:30
[INFO] [stdout]     |
[INFO] [stdout] 89  | / fn accumulate_descendants(
[INFO] [stdout] 90  | |     tree: &VecTree<String>,
[INFO] [stdout] 91  | |     out_tree: &mut VecTree<String>,
[INFO] [stdout] 92  | |     root_node: Index,
[INFO] [stdout] ...   |
[INFO] [stdout] 103 | |             let child_data = tree.get(child)?.clone();
[INFO] [stdout]     | |                              ^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 109 | |     Ok(())
[INFO] [stdout] 110 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:173:28
[INFO] [stdout]     |
[INFO] [stdout] 171 | / pub fn insert_tree(main_tree: &mut VecTree<String>, insert_tree: &VecTree<String>, from_main: Index) -> Result<(), ProcessingError> {
[INFO] [stdout] 172 | |     let mut stack = Vec::<(Index, Index)>::new();
[INFO] [stdout] 173 | |     stack.push((from_main, insert_tree.get_root_index()?));
[INFO] [stdout]     | |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] 174 | |
[INFO] [stdout] ...   |
[INFO] [stdout] 196 | |
[INFO] [stdout] 197 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:176:38
[INFO] [stdout]     |
[INFO] [stdout] 171 | / pub fn insert_tree(main_tree: &mut VecTree<String>, insert_tree: &VecTree<String>, from_main: Index) -> Result<(), ProcessingError> {
[INFO] [stdout] 172 | |     let mut stack = Vec::<(Index, Index)>::new();
[INFO] [stdout] 173 | |     stack.push((from_main, insert_tree.get_root_index()?));
[INFO] [stdout] 174 | |
[INFO] [stdout] 175 | |     while !stack.is_empty() {
[INFO] [stdout] 176 | |         let (main_idx, insert_idx) = stack.pop()?;
[INFO] [stdout]     | |                                      ^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 196 | |
[INFO] [stdout] 197 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:182:20
[INFO] [stdout]     |
[INFO] [stdout] 171 | / pub fn insert_tree(main_tree: &mut VecTree<String>, insert_tree: &VecTree<String>, from_main: Index) -> Result<(), ProcessingError> {
[INFO] [stdout] 172 | |     let mut stack = Vec::<(Index, Index)>::new();
[INFO] [stdout] 173 | |     stack.push((from_main, insert_tree.get_root_index()?));
[INFO] [stdout] 174 | |
[INFO] [stdout] ...   |
[INFO] [stdout] 182 | |                 if insert_tree.get(insert_child)? == main_tree.get(main_child)? {
[INFO] [stdout]     | |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 196 | |
[INFO] [stdout] 197 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:173:28
[INFO] [stdout]     |
[INFO] [stdout] 171 | / pub fn insert_tree(main_tree: &mut VecTree<String>, insert_tree: &VecTree<String>, from_main: Index) -> Result<(), ProcessingError> {
[INFO] [stdout] 172 | |     let mut stack = Vec::<(Index, Index)>::new();
[INFO] [stdout] 173 | |     stack.push((from_main, insert_tree.get_root_index()?));
[INFO] [stdout]     | |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] 174 | |
[INFO] [stdout] ...   |
[INFO] [stdout] 196 | |
[INFO] [stdout] 197 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:182:54
[INFO] [stdout]     |
[INFO] [stdout] 171 | / pub fn insert_tree(main_tree: &mut VecTree<String>, insert_tree: &VecTree<String>, from_main: Index) -> Result<(), ProcessingError> {
[INFO] [stdout] 172 | |     let mut stack = Vec::<(Index, Index)>::new();
[INFO] [stdout] 173 | |     stack.push((from_main, insert_tree.get_root_index()?));
[INFO] [stdout] 174 | |
[INFO] [stdout] ...   |
[INFO] [stdout] 182 | |                 if insert_tree.get(insert_child)? == main_tree.get(main_child)? {
[INFO] [stdout]     | |                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 196 | |
[INFO] [stdout] 197 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:176:38
[INFO] [stdout]     |
[INFO] [stdout] 171 | / pub fn insert_tree(main_tree: &mut VecTree<String>, insert_tree: &VecTree<String>, from_main: Index) -> Result<(), ProcessingError> {
[INFO] [stdout] 172 | |     let mut stack = Vec::<(Index, Index)>::new();
[INFO] [stdout] 173 | |     stack.push((from_main, insert_tree.get_root_index()?));
[INFO] [stdout] 174 | |
[INFO] [stdout] 175 | |     while !stack.is_empty() {
[INFO] [stdout] 176 | |         let (main_idx, insert_idx) = stack.pop()?;
[INFO] [stdout]     | |                                      ^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 196 | |
[INFO] [stdout] 197 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:182:20
[INFO] [stdout]     |
[INFO] [stdout] 171 | / pub fn insert_tree(main_tree: &mut VecTree<String>, insert_tree: &VecTree<String>, from_main: Index) -> Result<(), ProcessingError> {
[INFO] [stdout] 172 | |     let mut stack = Vec::<(Index, Index)>::new();
[INFO] [stdout] 173 | |     stack.push((from_main, insert_tree.get_root_index()?));
[INFO] [stdout] 174 | |
[INFO] [stdout] ...   |
[INFO] [stdout] 182 | |                 if insert_tree.get(insert_child)? == main_tree.get(main_child)? {
[INFO] [stdout]     | |                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 196 | |
[INFO] [stdout] 197 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:182:54
[INFO] [stdout]     |
[INFO] [stdout] 171 | / pub fn insert_tree(main_tree: &mut VecTree<String>, insert_tree: &VecTree<String>, from_main: Index) -> Result<(), ProcessingError> {
[INFO] [stdout] 172 | |     let mut stack = Vec::<(Index, Index)>::new();
[INFO] [stdout] 173 | |     stack.push((from_main, insert_tree.get_root_index()?));
[INFO] [stdout] 174 | |
[INFO] [stdout] ...   |
[INFO] [stdout] 182 | |                 if insert_tree.get(insert_child)? == main_tree.get(main_child)? {
[INFO] [stdout]     | |                                                      ^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 196 | |
[INFO] [stdout] 197 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:189:52
[INFO] [stdout]     |
[INFO] [stdout] 171 | / pub fn insert_tree(main_tree: &mut VecTree<String>, insert_tree: &VecTree<String>, from_main: Index) -> Result<(), ProcessingError> {
[INFO] [stdout] 172 | |     let mut stack = Vec::<(Index, Index)>::new();
[INFO] [stdout] 173 | |     stack.push((from_main, insert_tree.get_root_index()?));
[INFO] [stdout] 174 | |
[INFO] [stdout] ...   |
[INFO] [stdout] 189 | |                 next_main_child = main_tree.insert(insert_tree.get(insert_child)?.to_owned(), main_idx);
[INFO] [stdout]     | |                                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 196 | |
[INFO] [stdout] 197 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/climb/tree_tools.rs:189:52
[INFO] [stdout]     |
[INFO] [stdout] 171 | / pub fn insert_tree(main_tree: &mut VecTree<String>, insert_tree: &VecTree<String>, from_main: Index) -> Result<(), ProcessingError> {
[INFO] [stdout] 172 | |     let mut stack = Vec::<(Index, Index)>::new();
[INFO] [stdout] 173 | |     stack.push((from_main, insert_tree.get_root_index()?));
[INFO] [stdout] 174 | |
[INFO] [stdout] ...   |
[INFO] [stdout] 189 | |                 next_main_child = main_tree.insert(insert_tree.get(insert_child)?.to_owned(), main_idx);
[INFO] [stdout]     | |                                                    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `Result<(), ProcessingError>`
[INFO] [stdout] ...   |
[INFO] [stdout] 196 | |
[INFO] [stdout] 197 | | }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<Option<!>>` is not implemented for `Result<(), ProcessingError>`
[INFO] [stdout]     = note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 13 previous errors; 13 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 13 previous errors; 13 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0425.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0425.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "7db89f13ebba3ec004e2100d783d7c7c7c6a5dfc52d38000027de1d281dd4d33", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7db89f13ebba3ec004e2100d783d7c7c7c6a5dfc52d38000027de1d281dd4d33", kill_on_drop: false }`
[INFO] [stdout] 7db89f13ebba3ec004e2100d783d7c7c7c6a5dfc52d38000027de1d281dd4d33