Sqlx + postgres - how to insert a enum value

[imbolc]

Can't figure out how to use enums, here's the code:

CREATE TYPE enm AS ENUM ('foo', 'bar');
CREATE TABLE tbl (e enm);

use sqlx::postgres::PgPool;

#[derive(sqlx::Type)]
#[sqlx(rename = "enm", rename_all = "lowercase")]
enum Enm {
    Foo,
    Bar,
}

#[async_std::main]
async fn main() {
    let db = PgPool::connect("postgres:///sqlx_enum").await.unwrap();
    // error: unsupported type enm for param #1
    sqlx::query!("INSERT INTO tbl VALUES ($1)", Enm::Foo)
        .execute(&db)
        .await
        .unwrap();
}

[dazed_viper]

Try sqlx::query!("INSERT INTO tbl VALUES ($1)", Enm::Foo as Enm).

For queries returning rows you'd do:

struct Row {
    e: Enm,
};

sqlx::query_as!(Row,
    r#"INSERT INTO tbl VALUES ($1) RETURNING e AS "e!: Enm""#,
    Enm::Foo as Enm
)
.fetch_one(&db)
.await
.unwrap();

This is documented here: sqlx::query - Rust

Although I think the documentation could benefit from an explicit insertion example.

[imbolc]

Thank you Would you say a few words why these type overrides are needed? To my newbie eye they seem completely redundant.