{motive : Lean.Meta.Sym.BackwardRule → Sort u} →
  (t : Lean.Meta.Sym.BackwardRule) →
    ((expr : Lean.Expr) →
        (pattern : Lean.Meta.Sym.Pattern) →
          (resultPos : List ℕ) → motive { expr := expr, pattern := pattern, resultPos := resultPos }) →
      motive t