What type should I use to return a lazy_static value?

Question

I plan to have a struct which provides the JSON schema via a trait method. The schema is stored compiled in a lazy_static variable, but which type does my schema() function have to return?

lazy_static::lazy_static! {
    static ref DEF: serde_json::Value = serde_json::json!({
        "type": "object",
        "properties": {
            "name":         { "type": "string",
                            "minLength": 10,
                            },
        },
    });

    static ref SCHEMA: jsonschema::JSONSchema<'static> = jsonschema::JSONSchema::compile(&DEF).unwrap();
}

struct MySchema {
    name: String,
}

impl MySchema {
    pub fn schema() -> jsonschema::JSONSchema<'static> {
        SCHEMA
    }
}

#[test]
pub fn test() {
    let test = serde_json::json!({"name":"test"});
    assert_eq!(SCHEMA.is_valid(&test), false);
    assert_eq!(MySchema::schema().is_valid(&test), false);
}

I'll get this error

pub fn schema() -> jsonschema::JSONSchema<'static> {
                   ------------------------------- expected `JSONSchema<'static>` because of return type
    SCHEMA
    ^^^^^^ expected struct `JSONSchema`, found struct `SCHEMA`

Answer 1

I close this question with answer from Sven Marnach:

You can't return an owned value. You can only return a reference to the static variable. Change return type to &'static jsonschema::JSONSchema<'static> and the return value to &*SCHEMA.

lazy_static::lazy_static! {
    static ref SCHEMA: jsonschema::JSONSchema<'static> = jsonschema::JSONSchema::compile(&DEF).unwrap();
}

impl MySchema {
    pub fn schema() -> &'static jsonschema::JSONSchema<'static> {
        &*SCHEMA
    }
}