# perl -MO=Concise -e 'grep {defined} @array'
a  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 2 -e:1) v ->3
7     <|> grepwhile(other->8)[t2] vK/1 ->a
6        <@> grepstart K*/2 ->7
3           <0> pushmark s ->4
-           <1> null lK/1 ->4
-              <1> null sK/1 ->7
-                 <@> scope sK ->7
-                    <0> ex-nextstate v ->8
9                    <1> defined sK/1 ->-
-                       <1> ex-rv2sv sK*/1 ->9
8                          <$> gvsv(*_) s ->9
5           <1> rv2av[t1] lKM/1 ->6
4              <$> gv(*array) s ->5

# perl -MO=Concise -e 'grep defined, @array'
a  <@> leave[1 ref] vKP/REFC ->(end)
1     <0> enter ->2
2     <;> nextstate(main 1 -e:1) v ->3
7     <|> grepwhile(other->8)[t2] vK/1 ->a
6        <@> grepstart K/2 ->7
3           <0> pushmark s ->4
-           <1> null lK/1 ->4
9              <1> defined sK/1 ->7
-                 <1> ex-rv2sv sK*/1 ->9
8                    <$> gvsv(*_) s ->9
5           <1> rv2av[t1] lKM/1 ->6
4              <$> gv(*array) s ->5