E0119 rust type_error ai_generated true

error[E0119]: conflicting implementations of trait `Trait` for type `Type`

ID: rust/e0119-conflicting-implementations-of-trait

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85%Fix Rate
84%Confidence
1Evidence
2024-03-22First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
rustc 1.75.0 active — — —
rustc 1.78.0 active — — —
rustc 1.80.0 active — — —

Root Cause

Two or more impl blocks provide implementations of the same trait for the same type, or an impl conflicts with a blanket impl.

generic

中文

两个或多个 impl 块为同一类型提供了同一 trait 的实现，或者某个实现与 blanket impl 冲突。

Official Documentation

https://doc.rust-lang.org/error_codes/E0119.html

Workarounds

  1. 95% success Remove the duplicate impl block. Example: keep only one `impl Trait for MyType`. 
    Remove the duplicate impl block. Example: keep only one `impl Trait for MyType`.
  2. 85% success Use a newtype pattern to create a distinct type. Example: `struct MyWrapper(MyType);` and implement the trait for MyWrapper. 
    Use a newtype pattern to create a distinct type. Example: `struct MyWrapper(MyType);` and implement the trait for MyWrapper.
  3. 70% success If the conflict is with a blanket impl, add a type constraint or use specialization (if nightly) with `default impl`. Example: `impl<T: std::fmt::Debug> Trait for T { }`. 
    If the conflict is with a blanket impl, add a type constraint or use specialization (if nightly) with `default impl`. Example: `impl<T: std::fmt::Debug> Trait for T { }`.

中文步骤

  1. Remove the duplicate impl block. Example: keep only one `impl Trait for MyType`.
  2. Use a newtype pattern to create a distinct type. Example: `struct MyWrapper(MyType);` and implement the trait for MyWrapper.
  3. If the conflict is with a blanket impl, add a type constraint or use specialization (if nightly) with `default impl`. Example: `impl<T: std::fmt::Debug> Trait for T { }`.

Dead Ends

Common approaches that don't work:

  1. 50% fail

    If both impls are needed for different purposes, removing one will cause missing trait implementation errors elsewhere.

  2. 100% fail

    Rust doesn't have a lint to suppress conflicting impls; it's a fundamental type system error.

  3. 60% fail

    If the blanket impl covers the wrapper (e.g., impl<T> Trait for T), the conflict persists.