Failure not implemented

[masak]

<masak> niecza: say 4 ~~ Failure ?? 5 !! 42
<p6eval> niecza v17-4-ge5b869e: OUTPUT«===SORRY!===␤␤Expecting a term, but found either infix ?? or
          redundant prefix ?␤  (to suppress this message, please use space between ? ?) at /tmp/3SRuSARtcP line 1:␤
          ------> say 4 ~~ Failure ??⏏ 5 !! 42␤␤Parse failed␤␤»…
<masak> sorear: why do I get this? Failure is a term, no?
<masak> std: say 4 ~~ Failure ?? 5 !! 42
<p6eval> std 8632387: OUTPUT«ok 00:00 41m␤»
* masak submits nieczabug

[sorear]

Failure doesn't exist, so it's parsed as a listop.