14.4.2.2 Better function member

Given an argument list A with a set of argument types A1, A2, ?, AN and two
applicable function members MP
and MQ with parameter types P1, P2, ?, PN and Q1, Q2, ?, QN, MP is defined
to be a better function member
than MQ if
?for each argument, the implicit conversion from AX to PX is not worse
than the implicit conversion from
AX to QX, and
?for at least one argument, the conversion from AX to PX is better than
the conversion from AX to QX.
When performing this evaluation, if MP or MQ is applicable in its expanded
form, then PX or QX refers to a
parameter in the expanded form of the parameter list.