I too noticed that, before I posted the question. What's even wierder:

print    "With Parens[", scalar 1..10, "]";
print "\n";
print "Without Parens[",scalar(1..10), "]";
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Perl's range operator has wierd behavior, methinks... but why? Is there anything to fix that in my first case? I'm assuming it'd be a pretty large optimization over ternary operators...

The problem also existed with arrays that represented ranges, which was even wierder...  do_something $_ for ( @_[1..$#_] || 0..$#{$_[0]}) is the code that I was initially working with to no avail... I guess one could say the problem also is that in the case of for loops, @_[1..$#_] is being used in two contexts at the same time, and perl can't deal with that... The code was basically saying- if it it's there (in scalar context), use it in list context, and if it isn't there, use a diff. list.

Edit: BazB, added extra code tag.