菜单
Explain Cairo variable bindings, immutability, `mut`, constants, and shadowing; use when a request involves variable declaration, reassignment errors, changing types via shadowing, or defining constants in Cairo.
用 Codex 或 Claude 帮你安装 复制这段 Prompt，粘贴到 Codex、Claude 或其他助手里，让它检查 Skill 页面并帮你完成安装。
基于 SOC 职业分类
| name | cairo-variables-mutability |
| description | Explain Cairo variable bindings, immutability, `mut`, constants, and shadowing; use when a request involves variable declaration, reassignment errors, changing types via shadowing, or defining constants in Cairo. |
Guide variable bindings in Cairo, including immutability, mutation with mut, constants, and shadowing.
references/variables-mutability.md before answering.let, let mut, const, and shadowing.let.const, a type annotation, and global scope.x = 6 fail after let x = 5 in Cairo?"mut or shadowing when converting u64 to felt252?"Document Cairo language quirks, gotchas, and idiomatic workarounds; use when encountering unexpected compilation errors or behaviors in Cairo that differ from Rust.
Guide implementing custom numeric types in Cairo with invariant enforcement, overflow safety, and standard trait implementations; use when implementing fixed-point, signed integers, or other numeric primitives.
Explain how to write and run Cairo tests, including `#[test]`, assert macros, `#[should_panic]`, `#[ignore]`, and `#[available_gas]`; use when a request involves writing or running unit tests in Cairo.
Explain Cairo Array usage, ArrayTrait methods, array! macro, Span, and array read/write constraints; use when a request involves creating, updating, reading, or passing arrays in Cairo.
Explain Cairo associated items (functions, types, constants, implementations) in traits and impls; use when a request involves associated types, constants, or clarifying trait item placement in Cairo.
Explain Cairo closures, syntax, capture rules, type inference, and Fn traits; use when a request involves anonymous functions or passing behavior as a parameter in Cairo.