E0626 rust type_error ai_generated true

错误[E0626]：模式守卫求值时，借用可能仍在使用中

error[E0626]: borrow may still be in use when pattern guard evaluates

ID: rust/e0626-borrow-in-pattern-guard

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82%修复率
86%置信度
1证据数
2023-11-12首次发现

版本兼容性

版本状态引入弃用备注
rustc 1.73.0 active — — —
rustc 1.75.0 active — — —
rustc 1.78.0 active — — —

根因分析

`match` 分支的守卫条件中的借用可能在守卫求值时仍处于活动状态，因为编译器无法保证借用能在守卫运行前释放，可能导致别名冲突。

English

A borrow in a `match` arm's guard condition may still be active when the guard evaluates, because the compiler cannot guarantee the borrow is released before the guard runs, leading to potential aliasing violations.

generic

官方文档

https://doc.rust-lang.org/error_codes/E0626.html

解决方案

  1. Refactor the guard condition to use a separate `if let` or a function that takes ownership or a reference with a shorter lifetime.
  2. Bind the value with a reference pattern and then use a separate condition outside the match, e.g., using `matches!` macro.
  3. Use a `match` with a guard that does not borrow, e.g., by copying a boolean flag or using a method that returns a value without borrowing.

无效尝试

常见但无效的做法:

  1. 55% 失败

    Cloning creates a new value but the borrow of the original may still be active in the guard's scope; the compiler still sees the borrow.

  2. 65% 失败

    Unsafe code can bypass borrow checking but introduces memory safety risks; the compiler still emits the error in safe code.