[Proposal] KeyPath Dynamic Member Lookup (#1008)
[Proposal] KeyPath Dynamic Member Lookup (#1008)

* [Proposal] KeyPath Dynamic Member Lookup

This proposal attempts to enable stronger-typed version of
the dynamic member lookup by extending functionality of an
existing `@dynamicMemberLookup` attribute with key path based variants.

* Initiate review for SE-0252.

abertelrud/swift-evolution,Nirma/swift-evolution,apple/swift-evolution,DevAndArtist/swift-evolution,anandabits/swift-evolution,ddunbar/swift-evolution,DevAndArtist/swift-evolution,natecook1000/swift-evolution,anandabits/swift-evolution,hartbit/swift-evolution,natecook1000/swift-evolution,abertelrud/swift-evolution,hartbit/swift-evolution,Nirma/swift-evolution,apple/swift-evolution,ddunbar/swift-evolution