Ghost of IndexDistance past

This is odd:

let s = "abc"
let b = UInt64 (1)
let d = b + s.distance (from: s.startIndex, to: s.endIndex)
//warning: 'distance(from:to:)' is deprecated: all index distances 
// are now of type Int

Surely it should produce the same error as this:

let e = b + Int (s.distance (from: s.startIndex, to: s.endIndex))
//error: '+' is unavailable: Please use explicit type conversions or Strideable 
// methods for mixed-type arithmetics.