The definition of the protocol ViewModifer (SwiftUI.swift) includes the line "typealias Content." From what I read in the Swift docs, typealias requires a type. In fact, if I try to create a similar protocol by pasting the protocol code from SwuifUI.swift into my own file, Xcode gives the error "Type alias is missing an assigned type; use 'associatedtype' to define an associated type requirement."
FWIW, the ViewModifier protocol also has the line "associatedtype Body: View"
Can someone explain?