Rust errors / Types and traits
Rust compiler error · checked with rustc 1.99.0
Rust error E0322: explicit impls for the `Sized` trait are not permitted
What it meansA built-in trait was implemented explicitly. All implementations of the trait are provided automatically by the compiler.
What rustc prints
error[E0322]: explicit impls for the `Sized` trait are not permitted
--> main.rs:3:1
|
3 | impl Sized for Foo {} // error!
| ^^^^^^^^^^^^^^^^^^ impl of `Sized` not allowedReal output of rustc 1.99.0 compiling the official example below (2021 edition). Your names and line numbers will differ; the first line is the part to match.
The compiler team's explanation
A built-in trait was implemented explicitly. All implementations of the trait are provided automatically by the compiler.
Erroneous code example:
struct Foo;
impl Sized for Foo {} // error!The Sized trait is a special trait built-in to the compiler for types with a constant size known at compile-time. This trait is automatically implemented for types as needed by the compiler, and it is currently disallowed to explicitly implement it for a type.
From rustc --explain E0322 (1.99.0), part of the Rust project, MIT or Apache-2.0. Official page.
Related errors
- E0308mismatched types
- E0277the trait bound is not satisfied
- E0599no method named X found in the current scope
- E0433failed to resolve
- E0321cross-crate traits with a default impl, like `Send`, can only be implemented for a struct/enum type, not `&'static Foo`
- E0323item `N` is an associated const, which doesn't match its trait `Foo`
- E0324item `N` is an associated method, which doesn't match its trait `Foo`
Up next
Often hit nextE0308: mismatched typesA related error from the same family.Read it next →Did this answer your question?