swift234

[Parse] Stop ignoring private decls for incremental purposes. (#3352)

We'd really like to say that private decls can't affect other files,
but we don't have enough information at parse-time:

- Private members of non-private classes still show up in vtables,
  which affects subclasses and callers in other files.

- Private stored properties of non-private structs change the
  layout of the struct.

- Private types may be used in private stored properties, affecting
  the layout of the containing struct.

- Private decls of /any kind/ can be used as the initial value of a
  stored property without an explicit type.

    private class Evil {
      class func defaultAlignment() -> Alignment { return .evil }
    }
    public struct Character {
      // Inferred type here!
      private var alignment = Evil.defaultAlignment()
    }

To be safe and correct, go back to only ignoring method bodies.

https://bugs.swift.org/browse/SR-1030