The high-level intermediate representation of a literal.
A literal corresponds to a single character, where a character is either
defined by a Unicode scalar value or an arbitrary byte. Unicode characters
are preferred whenever possible. In particular, a
Byte variant is only
ever produced when it could match invalid UTF-8.
A single character represented by a Unicode scalar value.
A single character represented by an arbitrary byte.
othervalues to be equal, and is used by