DB<1>  %testHash =();

  DB<2> $destref = \$testHash{'a'}

  DB<3> x \%testHash;
0  HASH(0x302ee0c8)
   'a' => undef
  DB<4> $$destref = 42;

  DB<5>  x \%testHash;
0  HASH(0x302ee0c8)
   'a' => 42