private Statement rewriteOtherCondition(Expression condition, Expression message, boolean optOut) {
    Expression rewritten = optOut ? condition : convert(condition);

    final Expression executeAndVerify = rewriteToSpockRuntimeCall(resources.getAstNodeCache().SpockRuntime_VerifyCondition,
        condition, message, singletonList(rewritten), optOut);

    return surroundWithTryCatch(condition, message, executeAndVerify, optOut);
  }
Treat the nonsensical `!!` prefix as opt-out from implicit conditions
spock-core/src/main/java/org/spockframework/compiler/ConditionRewriter.java