If a conformance to a protocol is implied by several other
conformances (i.e. protocol P: Equatable {} and protocol Q: Equatable {} and a
type declares conformance to both P and Q), we should choose a source that's in
the same file as the type, if we can, because automatic synthesis of
conformances (for Equatable, Hashable, etc.) only works in that case.
Fixes rdar://problem/41852654.
'private' properties can't be accessed in extensions in Swift 3, so synthesizing
a conformance that reads from such things is going to be incorrect in an
extension.
This works for all protocols except for Decodable on non-final classes, because
the init requirement has to be 'required' and thus in the type's declaration.
Fixes most of https://bugs.swift.org/browse/SR-6803.
This converts the instances of the pattern for which we have a proper
substitution in lit. This will make it easier to replace it
appropriately with Windows equivalents.
Instead of warning about an unused result of a call to an implicit
function '__derived_enum_equals' or '__derived_struct_equals' use its
user-facing name '=='.
