Yep, there should be, or at least more specific docs on how things should act. Perl is awfully fuzzy about the behaviour of a lot of things. (Witness the fact that perl only recently nailed down the behaviour of numeric operations)

As a for example, in this:

  $a = $a + $a++;
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what should $a equal at the end? And if $a is tied or overloaded, what order should the tie/overload stuff be called in?