The syntax for pop is

pop ARRAY
pop
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which means

pop @NAME
pop @BLOCK
pop EXPR->@*
pop
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The block and the expression are expected to evaluate to a reference to an array. [ ... ] creates an array and a reference to it, and evaluates to a reference. This means you can use:

pop @{ [ 2, 4, 6 ] }
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or

pop [ 2, 4, 6 ]->@*
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Note that EXPR->@* requires Perl 5.24+. It's also available in Perl 5.20+ by adding both use feature qw( postderef ); and no warnings qw( experimental::postderef );, or by adding use experimental qw( postderef );.