rust lifetime_error ai_generated true

error[E0106]: missing lifetime specifier

ID: rust/e0106-missing-lifetime

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85%Fix Rate

90%Confidence

50Evidence

2023-01-01First Seen

Version Compatibility

Version	Status	Introduced	Deprecated	Notes
1	active	—	—	—

Function returns a reference but Rust can't infer the lifetime. Need explicit lifetime annotation.

generic

92% success Add lifetime parameter: fn foo<'a>(s: &'a str) -> &'a str
```
fn foo<'a>(s: &'a str) -> &'a str
```
Sources: https://doc.rust-lang.org/book/ch10-03-lifetime-syntax.html
85% success If function has one reference input, the compiler can infer (lifetime elision rules)
```
lifetime elision rules
```
Sources: https://doc.rust-lang.org/reference/lifetime-elision.html
80% success Consider returning an owned type (String, Vec) if lifetime complexity isn't worth it
```
Use owned types like String instead of &str, or Vec<T> instead of &[T], to avoid lifetime annotations
```
Sources: https://doc.rust-lang.org/book/ch10-03-lifetime-syntax.html

Common approaches that don't work:

Use 'static lifetime on everything 80% fail
'static means lives forever — wrong for most references
Return an owned value (String instead of &str) as a quick fix 55% fail
May work but cloning every time can be expensive

Frequently confused with: