perl -w -MData::Dumper -d \
-e '$Data::Dumper::Purity=1;' \
-e '$a={ type => "int" }; $b = \$a->{type};' \
-e '$c= [$b,$a];' \
-e '$d=$d= eval Dumper($c);'

  DB<1> c
Use of uninitialized value in scalar dereference at (eval 3)[-e:4] line 4.
Debugged program terminated. ... 
  DB<1> x $d
0  ARRAY(0x8306864)
   0  SCALAR(0x83068c4)
      -> 'int'
   1  HASH(0x83068a0)
      'type' => undef    <<<<<<<<<<<<<<<<  hey?
  DB<2> x $c
0  ARRAY(0x82f3fac)
   0  SCALAR(0x80f621c)
      -> 'int'
   1  HASH(0x8306af8)
      'type' => 'int'