Vapor Swift Fluent : Type of expression is ambiguous without more context

Question

This is my route :

router.get("answers","delete", Int.parameter) { req -> Future<Response> in

        let answerID = try req.parameters.next(Int.self)
        guard let _ = getUsername(req) else {
            throw Abort(.unauthorized)
        }
        return Message.query(on: req).filter(\.id == answerID).first().map(to: Response.self) { answer in
            guard let answer = answer else {
                throw Abort(.notFound)
            }
            return answer.delete(on: req).map(to: Response.self) { _ in
                return req.redirect(to: "/answers")
            }
        }
    }

But for xCode this is Ambiguous without more context .filter(\.id == answerID)

And this is my struct Message :

struct Message: Content, SQLiteUUIDModel, Migration {
var id: UUID?
var username: String
var content: String
var category: String
var question: String
var date: Date

}

I don't understand because I use filters on ids in many other routes and it's the first time I show this error.

I googled this and it seems that the errors shows up when Fluent is not imported but I've already import Fluent at the top.

Answer 1

I just had time to test your code. If you replace

...   .map(to: Response.self) { answer in ....

with

... .flatMap(to:Response.self) { answer in ...

it works.