A struct's or struct-like enum variant's field was specified more than once.
Erroneous code example:
```compile_fail,E0062
struct Foo {
x: i32,
}
fn main() {
let x = Foo {
x: 0,
x: 0, // error: field `x` specified more than once
};
}
```
This error indicates that during an attempt to build a struct or struct-like
enum variant, one of the fields was specified more than once. Each field should
be specified exactly one time. Example:
```
struct Foo {
x: i32,
}
fn main() {
let x = Foo { x: 0 }; // ok!
}
```