version 5.022000 at pm/warn_undef0.pl line 4.
Use of uninitialized value $hash{"a"} in concatenation (.) or string at pm/warn_undef0.pl line 13.
hash  at pm/warn_undef0.pl line 13.
Use of uninitialized value in concatenation (.) or string at pm/warn_undef0.pl line 14.
hoa  at pm/warn_undef0.pl line 14.
Use of uninitialized value in concatenation (.) or string at pm/warn_undef0.pl line 16.
hashref  at pm/warn_undef0.pl line 16.
Use of uninitialized value in concatenation (.) or string at pm/warn_undef0.pl line 17.
hoa ref  at pm/warn_undef0.pl line 17.
Use of uninitialized value $array[1] in concatenation (.) or string at pm/warn_undef0.pl line 19.
array   at pm/warn_undef0.pl line 19.
Use of uninitialized value in concatenation (.) or string at pm/warn_undef0.pl line 20.
aoh   at pm/warn_undef0.pl line 20.
Use of uninitialized value in concatenation (.) or string at pm/warn_undef0.pl line 22.
array ref   at pm/warn_undef0.pl line 22.
Use of uninitialized value in concatenation (.) or string at pm/warn_undef0.pl line 23.
aoh   ref   at pm/warn_undef0.pl line 23.