As I said, Perl 5 in my opinion is impossible to be really parsed without run the code. This is way I still wait Perl 6, that is not so dependent of runtime states to define code.

Perl - like many other "dynamic languages" - is just too flexible to be statically analyzed with certainty. This is not a parsing problem. LISP (which famously has "no syntax" and is completely trivial to parse) has the same issues.

Consider this:

my $method = "method_name";
for my $class (qw(Class1 Class2 Class3)) {
  my $object = $class->$method(shift (@arguments));
}
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Now consider that all the string literals in this code are just strings, and can come from anywhere else, including files, databases, user input etc.