tests/standalone/regress_52691_test.dart

import 'package:expect/expect.dart';

void main() {
  try {
    var re = RegExp(r'[c-');
  } on FormatException catch (e, s) {
    Expect.equals(
      "FormatException: Unterminated character class [c-",
      e.toString(),
    );
  }
}