Default value for $scale should not be null (arccos, arctan, arcsec, arccsc, tan, cotan etc.)

[gregor-tb]

public function arccos(int $scale = null): Decimal

$scale is null here by default, but used like (int) 0. This is working in the additions $scale + 2 etc., but crashes on calling round(int) method, which does not accept null.

But later it is checked for explicit null value

$scale = ($scale === null) ? 32 : $scale;