struct
Foo
{
    var     id: UUID?
    var     s: String?
    var     bars: [Bar]?
}

struct
FooContent
{
    var bars: [BarContent]?
    
    init(from: Foo)
    {
        self.bars = from.bars.map { BarContent(from: $0) }
    }
}

struct
Bar
{
}

struct
BarContent
{
    var     id: UUID?
    var     s: String?
    
    init(id: UUID?, s: String?)
    {
        self.id = id
        self.s = s
    }
}

error: EventSim.playground:156:48: error: extra argument 'from' in call
                self.bars = from.bars.map { BarContent(from: $0) }
                                                             ^~

error: EventSim.playground:156:41: error: missing arguments for parameters 'id', 's' in call
                self.bars = from.bars.map { BarContent(from: $0) }
                                                      ^

EventSim.playground:171:2: note: 'init(id:s:)' declared here
        init(id: UUID?, s: String?)
        ^