How to get bundle for a struct?

extension Bundle {
    static var current: Bundle {
        class __ { }
        return Bundle(for: __.self)
    }
}

The best solution here depends on what you need a bundle for.

Is it to look up resources that exist only in a specific app, framework, or extension bundle that's known to be loaded when the code you're writing runs? In that case you might want to use init(identifier:) instead of dynamically looking up the bundle that defines a certain type.

Beware of "follows the type" bundle lookups. For example, if a framework class Foo uses NSBundle(forClass: self.dynamicType) to load a resource, a subclass of Foo defined by the app loading that framework will end up looking in the app bundle instead of the framework bundle.

If you do need a "follows the type" bundle lookup for a struct (or enum), one workaround that might prove helpful is to define a class as a subtype:

struct Foo {
     class Bar {}
     static var fooBundle: NSBundle { return NSBundle(forClass: Foo.Bar.self) }
}

Note there's nothing dynamic here, because nothing needs to be — every Foo comes from the same type definition (because structs can't inherit), so its static type matches its dynamic type.

(Admittedly, an NSBundle(forType:) that could handle structs, enums, and protocols might make a nice feature request. Though I imagine it could be tricky to make it handle extensions and everything...)

Updated for Swift 3.0+:

struct Foo {
     class Bar {}
     static var fooBundle: Bundle { return Bundle(for: Foo.Bar.self) }
}