On master branch rocket_contrib, FromRequest not implemented for Json<T>

[DanielJoyce]

the trait bound rocket_contrib::json::Json<CreateProjectFolderRequest>: FromRequest<'_, '_> is not satisfied
the trait FromRequest<'_, '_> is not implemented for rocket_contrib::json::Json<CreateProjectFolderRequest>

use rocket_contrib::json::Json;

#[post("/users", format = "json", data = "<user>")]
fn new_user(user: Json<User>) {
    /* ... */
}

This won't work from the docs.

[DanielJoyce]

rocket_contrib = { git = "https://github.com/SergioBenitez/Rocket", version = "0.5.0-dev", features = ["uuid"] }

json is a default feature, and works in all other ways. It's just the data guard doesn't work

[DanielJoyce]

Looking at the source it appears FromRequest is missing.

[SergioBenitez]

Json is not and has never been a request guard, and thus does not implement FromRequest. It is a data guard, however, and does implement FromData. This is true in master. Many, many tests check for this. That exact docstring is tested, for instance.

I suspect you have a typo in your program or are not using the data route argument. If the former, Rocket will tell you which parameters are extra or missing. If the latter, you'll see the type mismatch error since you'll have used Json as a request guard.

[SergioBenitez]

What does "pure" JSON mean? Is it just JSON? Then Json. I'm not sure how we can be clearer than what the docs say now:

To parse request body data as JSON , add a data route argument with a target type of Json<T>, where T is some type you’d like to parse from JSON. T must implement serde::Deserialize.

[DanielJoyce]

Doesn't matter. Figured it out. :)