Heh; just in case someone takes a close look at that error message and is terribly confused... here's the correctly pasted one:
<masak> m: multi infix:«≃» { $^l lt $^r }; multi infix:«!≃» { not($^l ≃ $^r) }; say "foo" !≃ "bar" <camelia> rakudo-moar d8c834: OUTPUT«===SORRY!=== Error while compiling /tmp/weCLGmom3MCannot negate ≃ because it is not iffy enoughat /tmp/weCLGmom3M:1------> ix:«!≃» { not($^l ≃ $^r) }; say "foo" !≃⏏ "bar"» That's better. Nothing to see here, move along.