C:\test\primes>perl -Mstrict -MList::Util=reduce -wE" say reduce{ $a +$b } 1,2,3"
'main'
6

C:\test\primes>perl -Mstrict -wE"package fred; use List::Util qw[ reduce ]; say reduce{ $a +$b } 1,2,3"
'main'
Name "fred::a" used only once: possible typo at -e line 1.
Name "fred::b" used only once: possible typo at -e line 1.
6