Framework authors can use SwiftWraper:none to bring back string enums
to type alias of String. When diagnosing source breaking changes, these
type alias are shown as removed. Therefore, it's hard to tell whether these
changes are automatically migratable. This patch refines the
removed-type-alias by further analyzing whether a
RawRepresentable with the same usr appeared in the later version of
SDK. If there is, another kind of message is emitted for differentiation.
This patch restricts the detection of moved members to be static members,
since only in this case we need to update qualified access to
them. The move of instance members will be either handled by rename or
we don't need to update anything at all.
Additionally, this patch introduces a sub-kind of type member diff item
called qualified replacement to describe the aforementioned case. However,
the migrator part has not started to honor this sub-kind yet.
rdar://32466196
Different from type hoist that moves global variables to static member
variables, we've also seen member variables being moved among different
types via apinotes. Swift-api-digester should be able to detect such
case so that migrator can handle them properly.
rdar://32466196
