Error code E0322
A built-in trait was implemented explicitly. All implementations of the trait are provided automatically by the compiler.
Erroneous code example:
#![allow(unused)] fn main() { 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.