If the value p being boxed is an integer literal of type int between -128 and 127
inclusive (§3.10.1), or the boolean literal true or false (§3.10.3), or a character
literal between 'u0000' and 'u007f' inclusive (§3.10.4), then let a and b be the
results of any two boxing conversions of p. It is always the case that a == b.