Because !! is a (moderately known) idiom as well (the "boolification" operator), I don't think that needs to be split up. My snap reaction to seeing ('foo') x!! $bar is a "huh?" until my brain parses x!! into two separate things. My snap reaction to ('foo') x !!$bar is immediately "list repeated boolean times".
Separately, I was thinking of parallels to "boolification" for a name, but it's not true or false -- it's a "there or not there" operator. That made me think first of the Cheshire Cat fading in and out, and the cat idea reminded me of Schrodinger's Cat and other quantum mechanical metaphors. Maybe there's a good name in there somewhere.
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