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From: Eric Sosman <esosman@comcast-dot-net.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: ensuring unreachability
Date: Wed, 18 Feb 2015 10:16:27 -0500
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On 2/18/2015 9:40 AM, Jukka Lahtinen wrote:
> Eric Sosman <esosman@comcast-dot-net.invalid> writes:
>
>>      Remember, the underlying purpose is to guard against a
>> maintainer who might inadvertently introduce a fall-through.
>
> Why not just insert the break; for every case?
> That's what it is for.

     The original code was oddly structured:

	case E1:
	    if (...) {
	       ...; return;
	    } else if (...) {
	       ...; throw ...;
	    } else {
	       ...; continue;
	    }
	case E2:
	    ...

Inserting a `break' right before the E2 case would provoke a
compile-time error because the statement would be unreachable.

     Andreas worries that someone might add a new alternative
to the `if' ladder, one that doesn't `return' or `throw' or
otherwise exit the `switch', thereby producing an unwanted
fall-through into E2.  I think the most straightforward way to
accomplish this is to eliminate the final `else' and brackets,
putting the `...; continue;' at the "top level" of the case.

-- 
esosman@comcast-dot-net.invalid
"Don't be afraid of work. Make work afraid of you." -- TLM