(motive : Option Lean.DelayedMetavarAssignment → Sort u_1) →
  (__discr : Option Lean.DelayedMetavarAssignment) →
    ((decl : Lean.DelayedMetavarAssignment) → motive (some decl)) →
      ((x : Option Lean.DelayedMetavarAssignment) → motive x) → motive __discr