14.9.7 String equality operators

The predefined string equality operators are:
bool operator ==(string x, string y);
bool operator !=(string x, string y);
Two string values are considered equal when one of the following is true:
?Both values are null.
?Both values are non-null references to string instances that have
identical lengths and identical
characters in each character position.
The string equality operators compare string values rather than string
references. When two separate string
instances contain the exact same sequence of characters, the values of the
strings are equal, but the
references are different. [Note: As described in ?4.9.6, the reference
type equality operators can be used to
compare string references instead of string values. end note]