{motive : Lean.Server.Completion.Context✝ → Sort u} →
  (t : Lean.Server.Completion.Context✝¹) →
    ((mod : Lean.Name) →
        (pos : Lean.Lsp.Position) →
          (completionInfoPos : ℕ) → motive { mod := mod, pos := pos, completionInfoPos := completionInfoPos }) →
      motive t