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A pattern binding is using the same name as one of the variants of a type.
Erroneous code example:
```compile_fail,E0170
# #![deny(warnings)]
enum Method {
GET,
POST,
}
fn is_empty(s: Method) -> bool {
match s {
GET => true,
_ => false
}
}
fn main() {}
```
Enum variants are qualified by default. For example, given this type:
```
enum Method {
GET,
POST,
}
```
You would match it using:
```
enum Method {
GET,
POST,
}
let m = Method::GET;
match m {
Method::GET => {},
Method::POST => {},
}
```
If you don't qualify the names, the code will bind new variables named "GET" and
"POST" instead. This behavior is likely not what you want, so `rustc` warns when
that happens.
Qualified names are good practice, and most code works well with them. But if
you prefer them unqualified, you can import the variants into scope:
```
use Method::*;
enum Method { GET, POST }
# fn main() {}
```
If you want others to be able to import variants from your module directly, use
`pub use`:
```
pub use Method::*;
pub enum Method { GET, POST }
# fn main() {}
```
|
