presto-main/src/main/java/io/prestosql/operator/scalar/Re2JCastToRegexpFunction.java/Re2JCastToRegexpFunction/specialize
class Re2JCastToRegexpFunction:    @Override
    public ScalarFunctionImplementation specialize(BoundVariables boundVariables, int arity, Metadata metadata)
    {
        return new ScalarFunctionImplementation(
                false,
                ImmutableList.of(valueTypeArgumentProperty(RETURN_NULL_ON_NULL)),
                insertArguments(METHOD_HANDLE, 0, dfaStatesLimit, dfaRetries, padSpaces, boundVariables.getLongVariable("x")));
    }