There are some exceptions to 1 above. If the character contained is numerically zero, then despite having length, the string will conditionally test as false.
...
And then there are (the celebrated) exceptions to the exception, like "0e0" (& "0e-0" & ... ) that the 'type safety' people hate, but that help make the world go around.
There are only exceptions to the exception because of you convoluted way of writing what is false. If you state it as:

An expression is false if it (in scalar context -- boolean context is scalar context) evaluates to any of the following:

No exceptions. No exceptions to exceptions. And it has nothing to do with types.

Update: if a variable has both string and numerical values, then the truth value of the string part wins: 

use Scalar::Util 'dualvar';
my $p1 = dualvar 0, "foo";   # True
my $p2 = dualvar 1, "";      # False

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In reply to Re^2: String comparison "\x00" vs. "". by JavaFan
in thread String comparison "\x00" vs. "". by asprillia

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