utility-types.ts:13:7 - error SC2006: values of type '{ [s: symbol]: string; }' cannot be compiled: this index signature is outside the supported shape (string or number keys; values limited to numbers, strings, booleans, records, classes, arrays, unions, functions, Maps, Sets, RegExps, Dates, Promises, or 'unknown')

  12 | // named recursive shapes; differential corpus covers both.)
  13 | const bySymbol: { [s: symbol]: string } = {};
     |       ^~~~~~~~
  14 | console.log(bySymbol);

  hint: string- and number-keyed index signatures over the supported value types compile directly; symbol keys and dual signatures with unequal value types have no lowering