bash
cargo checkNotes
Useful for fast feedback when the goal is to surface compiler errors quickly.
Rust CLI Troubleshooting: Build Errors and Diagnostics
Commands for investigating compiler errors, Cargo diagnostics, verbose output, and fix suggestions in Rust CLI projects.
Export
Copy the compact sheet, download it, or print it.
Download
`D` dense toggle · `C` copy all
Compiler diagnostics
Find, expand, and inspect rustc and Cargo errors faster.
bash
cargo build -vNotes
Helpful when you need to see more about dependency builds, commands, and build-script activity.
bash
cargo build -vvNotes
Useful when debugging build scripts or understanding what Cargo is invoking.
Emit machine-readable diagnostics
Print messages in JSON form for editor tooling or scripts.
bashANYcargocheckjsondiagnostics
bash
cargo check --message-format=jsonNotes
Useful for custom tooling, scripts, or inspecting structured compiler diagnostics.
Apply compiler suggestions automatically
Use rustc suggestions to fix straightforward issues.
bashANYcargofixdiagnostics
bash
cargo fixNotes
Cargo can apply a subset of compiler suggestions automatically when they are safe and well understood.
Apply suggestions even with a broken crate
Try fixing code even if the crate currently does not compile cleanly.
bashANYcargofixbroken-code
bash
cargo fix --broken-codeNotes
Helpful when doing broad refactors, but review changes carefully afterward.
Explain a specific compiler error
Open a detailed explanation for an error code such as E0308.
bashANYrustcerror-indexexplain
bash
rustc --explain E0308Notes
The Rust error index provides longer explanations and examples for compiler error codes.
bash
cargo build --timingsNotes
Useful for troubleshooting unexpectedly slow builds in larger CLI projects.
Common error patterns
Examples for recurring Rust CLI compiler issues.
rust
let port: u16 = "3000";Notes
This typically triggers a type mismatch error because a string literal cannot be assigned to a numeric variable.
Borrow after move example
Illustrates a move-related ownership error.
rustANYrustownershipmoveerrors
rust
let name = String::from("cli");
let moved = name;
println!("{}", name);Notes
After moving `name` into `moved`, using `name` again triggers an ownership error.
Missing trait import example
Method exists but the trait is not in scope.
rustANYrusttraitsimportserrors
rust
use std::fs::File;
fn main() {
let mut file = File::create("out.txt").unwrap();
file.write_all(b"hello").unwrap();
}Notes
This commonly fails until `use std::io::Write;` is imported so the trait method is in scope.
Use `?` with a fallible function
Return a compatible `Result` when using the question-mark operator.
rustANYrustresultquestion-markerrors
rust
use std::fs;
fn load() -> std::io::Result<String> {
let content = fs::read_to_string("Cargo.toml")?;
Ok(content)
}Notes
A common mistake is using `?` in a function that does not return a compatible `Result` or `Option`.
More in Rust CLI
Rust CLI Troubleshooting: CI, Environment, Build Scripts, and Publishing
Commands for debugging CI failures, environment mismatches, build script output, installation problems, and publish checks in Rust CLI projects.
Rust CLI Troubleshooting: rustup, Toolchains, Components, and Targets
Commands for fixing toolchain mismatches, missing components, and cross-compilation target issues in Rust CLI projects.
Rust CLI Troubleshooting: Tests, Doctests, and Documentation
Commands for debugging failing tests, capturing output, isolating flaky cases, and fixing documentation-generation issues in Rust CLI projects.
Rust CLI Troubleshooting: Dependencies, Features, and Lockfiles
Commands for analyzing dependency trees, feature activation, duplicate crates, and lockfile behavior in Rust CLI projects.
Rust CLI Troubleshooting: Manifest, Packages, and Workspaces
Commands and examples for debugging Cargo.toml issues, package selection mistakes, and workspace confusion in Rust CLI repos.
Rust CLI Cargo Config, Environment, Docs, and Debugging
Cargo configuration, environment variables, docs generation, and troubleshooting commands for Rust CLI development.