E0599 rust type_error ai_generated true

error[E0599]: no method named `parse` found for struct `String` in the current scope

ID: rust/e0599-no-method-named-parse-found

Also available as: JSON · Markdown · 中文
90%Fix Rate
82%Confidence
1Evidence
2023-06-20First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
1.65 active — — —
1.70 active — — —
1.75 active — — —

Root Cause

Calling `.parse()` on a String without importing the `FromStr` trait or providing a type annotation for the result.

generic

中文

在 String 上调用 `.parse()` 时没有导入 `FromStr` trait 或为结果提供类型注解。

Official Documentation

https://doc.rust-lang.org/error-index.html#E0599

Workarounds

  1. 95% success Add a type annotation to the result: `let num: u32 = my_string.parse().unwrap();` 
    Add a type annotation to the result: `let num: u32 = my_string.parse().unwrap();`
  2. 95% success Use turbofish syntax: `my_string.parse::<u32>().unwrap();` 
    Use turbofish syntax: `my_string.parse::<u32>().unwrap();`
  3. 90% success Explicitly call `FromStr::from_str`: `u32::from_str(&my_string).unwrap();` 
    Explicitly call `FromStr::from_str`: `u32::from_str(&my_string).unwrap();`

中文步骤

  1. Add a type annotation to the result: `let num: u32 = my_string.parse().unwrap();`
  2. Use turbofish syntax: `my_string.parse::<u32>().unwrap();`
  3. Explicitly call `FromStr::from_str`: `u32::from_str(&my_string).unwrap();`

Dead Ends

Common approaches that don't work:

  1. Adding `use std::str::FromStr;` but not specifying the target type 80% fail

    The parse method requires type inference; without a type hint, the compiler cannot determine the output type.

  2. Using `as` cast: `my_string as u32` 95% fail

    String cannot be cast to numeric types with `as`; only primitive numeric types can be cast.