This commit changes the behaviour of the error for
passing a temporary pointer conversion to an
@_nonEphemeral parameter such that it doesn't
affect overload resolution. This is done by recording
the fix with an impact of zero, meaning that we don't
touch the solution's score.
In addition, this change means we no longer need
to perform the ranking hack where we favour
array-to-pointer, as the disjunction short-circuiting
will continue to happen even with the fix recorded.
Diagnose ephemeral conversions that are passed to @_nonEphemeral
parameters. Currently, this defaults to a warning with a frontend flag
to upgrade to an error. Hopefully this will become an error by default
in a future language version.
