// RUN: %target-swift-frontend -primary-file %s -emit-ir | |
extension Dictionary { | |
init<S: Sequence>(grouping elements: S, by keyForValue: (S.Iterator.Element) -> Key) | |
where Array<S.Iterator.Element> == Value | |
{ | |
self = [:] | |
for value in elements { | |
var values = self[keyForValue(value)] ?? [] | |
values.append(value) | |
self[keyForValue(value)] = values | |
} | |
} | |
} |