| name | rust-conventions |
| description | Rust conventions: inline interpolation in format strings, one consolidated import group per file, checked arithmetic for value operations, and the fmt/clippy gate before committing. TRIGGER when writing, editing, or reviewing Rust — any `.rs` file, a Cargo workspace, or a diff containing Rust. DO NOT TRIGGER for other languages, or for illustrative Rust in prose that is never compiled.
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Rust Conventions
String Formatting
Use inline variable interpolation:
println!("Hello {name}");
format!("Processing {block_number} at slot {slot}");
error!("Failed to load {path}: {error}");
Positional {} placeholders are not used. This applies to every formatting
macro: println!, format!, info!, warn!, error!, debug!, trace!,
panic!, assert!, write!.
Import Organization
All use statements sit in a single consolidated group at the top of the file.
Imports are never split mid-file or placed inside functions.
Checked Arithmetic
Value operations use checked arithmetic:
let result = value.checked_add(amount).ok_or(Error::Overflow)?;
let difference = total.checked_sub(fee).ok_or(Error::InsufficientFunds)?;
Bare +, -, * are reserved for arithmetic that carries no value semantics.
Function-Local Statics
A process-lifetime singleton whose only consumer is one function is declared
inside that function:
static FOO: OnceCell<T> = OnceCell::const_new();
Put it inside get() rather than at module level when there is exactly one
caller.
Before Committing
cargo +nightly fmt --all && cargo clippy
