 /// a metatype, make it conform to _ObjectiveCBridgeable, and its witness table
 /// will be ABI-compatible with one that directly provided conformance to the
 /// metatype type itself.
-@_fixed_layout
 public struct _BridgeableMetatype: _ObjectiveCBridgeable {
-  @usableFromInline // FIXME(sil-serialize-all)
   internal var value: AnyObject.Type
 
-  @inlinable // FIXME(sil-serialize-all)
   internal init(value: AnyObject.Type) {
     self.value = value
   }
 
   public typealias _ObjectiveCType = AnyObject
 
-  @inlinable // FIXME(sil-serialize-all)
   public func _bridgeToObjectiveC() -> AnyObject {
     return value
   }
 
-  @inlinable // FIXME(sil-serialize-all)
   public static func _forceBridgeFromObjectiveC(
     _ source: AnyObject,
     result: inout _BridgeableMetatype?

    result = _BridgeableMetatype(value: source as! AnyObject.Type)
  }

  @inlinable // FIXME(sil-serialize-all)
  public static func _conditionallyBridgeFromObjectiveC(
    _ source: AnyObject,
    result: inout _BridgeableMetatype?

    return false
  }

  @_effects(readonly)
  public static func _unconditionallyBridgeFromObjectiveC(_ source: AnyObject?)
      -> _BridgeableMetatype {
