E0308 rust type_error ai_generated true

error[E0308]: mismatched types -- expected `i32`, found `u32`

ID: rust/e0308-mismatched-types-expected-i32-found-u32

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95%Fix Rate
90%Confidence
1Evidence
2023-04-05First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
rustc 1.60.0 active — — —
rustc 1.65.0 active — — —
rustc 1.70.0 active — — —

Root Cause

A value of one integer type is used where a different integer type is expected, due to Rust's strict type system not allowing implicit conversions.

generic

中文

由于Rust严格的类型系统不允许隐式转换，在期望一种整数类型的地方使用了另一种整数类型。

Official Documentation

https://doc.rust-lang.org/error_codes/E0308.html

Workarounds

  1. 95% success Use explicit conversion with `From` or `TryFrom` traits, e.g., `i32::try_from(u32_val)` and handle the Result. 
    Use explicit conversion with `From` or `TryFrom` traits, e.g., `i32::try_from(u32_val)` and handle the Result.
  2. 90% success If the value is guaranteed to fit, use `as` cast with a comment explaining safety. 
    If the value is guaranteed to fit, use `as` cast with a comment explaining safety.

中文步骤

  1. 使用`From`或`TryFrom`特征进行显式转换，例如`i32::try_from(u32_val)`并处理Result。
  2. 如果值保证在范围内，使用`as`强制转换并添加注释说明安全性。

Dead Ends

Common approaches that don't work:

  1. 70% fail

    `as` cast can silently truncate or wrap, leading to data loss; it's not a clean conversion.

  2. 60% fail

    If the source value is inherently u32 (e.g., from an API), changing the variable type may cause other mismatches.

  3. 95% fail

    Unsafe coercion is dangerous and undefined behavior; it doesn't solve the type mismatch.