checkAsKeyPatt = (specimen, keyAsPattern, check) => {
    if (isKey(specimen) && keyEQ(specimen, keyAsPattern)) {
      return true;
    }
    return (
      check !== identChecker &&
      // When the mismatch occurs against a key used as a pattern,
      // the pattern should still be redacted.
      check(false, X`${specimen} - Must be: ${keyAsPattern}`)
    );
  }
@param {any} specimen
@param {Key} keyAsPattern
@param {Checker} check
@returns {boolean}