./perl6 -e 'my Num $s;my Num $i;for 1..10000 -> $i {$s+=1/$i**2};say $s'
Type check failed in assignment to '$s'; expected 'Num' but got 'Rat'
  in method reify at src/gen/CORE.setting:4471
  in method reify at src/gen/CORE.setting:4376
  in method reify at src/gen/CORE.setting:4376
  in method gimme at src/gen/CORE.setting:4740
  in method eager at src/gen/CORE.setting:4715
  in method eager at src/gen/CORE.setting:1028
  in sub eager at src/gen/CORE.setting:5000