pub fn preference_key() -> &'static ConformanceExpand description
A PreferenceKey conformance whose Value is Swift.Int.
A preference key is an identity, never a value: SwiftUI instantiates the
Value, not the key. So the key can be any nominal type, and this borrows
SwiftUI.Spacer rather than synthesizing a type descriptor of its own.
Not a stdlib type, though — Swift.Int is the obvious candidate and it does
not work. Registering a conformance for it leaves
swift_conformsToProtocol still reporting none, presumably because the
runtime resolves stdlib types by a path that does not consult registered
records. A framework type registers and resolves normally.