lent parameter: invalid C codegen

[ringabout]

nim-lang#16898

  elif n.kind in {nkCommand, nkCall} and n[0].kind in {nkIdent, nkSym, nkOpenSymChoice, nkClosedSymChoice} and
      considerQuotedIdent(c, n[0]).s == "lent":
    localError(c.config, n[0].info, "'" & considerQuotedIdent(c, n[0]).s & "' is only allowed in return types!")
    result = semTypeNode(c, n, nil)

[ringabout]

Now here is a PR
nim-lang#17628