Rust errors / Types and traits
Rust compiler error · checked with rustc 1.99.0
Rust error E0203: duplicate relaxed `Sized` bounds
What it meansHaving duplicate relaxed default bounds is unsupported.
What rustc prints
error[E0203]: duplicate relaxed `Sized` bounds
--> main.rs:1:15
|
1 | struct Bad<T: ?Sized + ?Sized>{
| ^^^^^^ ^^^^^^Real 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.
E0203Types and traits
Activein rustc 1.99.0
8related errors linked below
The compiler team's explanation
Having duplicate relaxed default bounds is unsupported.
Erroneous code example:
struct Bad<T: ?Sized + ?Sized>{
inner: T,
}Here the type parameter T cannot have duplicate relaxed bounds for default trait Sized. This can be fixed by only using one relaxed bound:
struct Good<T: ?Sized>{
inner: T
}From rustc --explain E0203 (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
- E0200the trait `Bar` requires an `unsafe impl` declaration
- E0201duplicate definitions with name `baz`:
- E0204the trait Copy cannot be implemented for this type
- E0206the trait `Copy` cannot be implemented for this type
Up next
Often hit nextE0308: mismatched typesA related error from the same family.Read it next →Did this answer your question?