Unary + doesn't do anything on its operand, unlike unary - which does force scalar context:

use v5.14;
use warnings;
use strict;

sub array
{
  my @array = ("Hello ", "World");
  @array;
}

say array;
say+array;
say-array; # warning here
say scalar array;
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Ambiguous use of -array resolved as -&array() at context.pl line 13.
Hello World
Hello World
-2
2
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