Not that being explicit is always a bad thing:
$val = some_cond()
?? ($arg1 // $arg1_default)
// ($arg2 // $arg2_default)
No. What's a bad thing is creating new linguistic traps for when people
inevitably forget to be explicit.
And I question your notion of "highly useful" in this case.
Huh??? Both // and the ternary are unquestionably highly useful constructs. My
point was that making them not work together is a Very Bad Idea.
I guess the thing that I really think is nice is getting :: out of
that role and into the type-only domain.
Yes, I'd certainly like that too. But not at the cost of turning // into a
bear-pit for the unsuspecting.