Sean Kelly wrote:
On Aug 18, 2011, at 10:29 AM, Nick Sabalausky wrote:

"Bernard Helyer" <b.hel...@gmail.com> wrote in message news:j2ithq$12kd$1...@digitalmars.com...
I asked the Ars forums ( http://arstechnica.com/civis/viewtopic.php?
f=20&t=1153378&p=21965411 ) and I ask the same of you: should
unambiguously unreachable code be an error or a warning? ( see the linked
forum post for more details ).
No. That would be a royal pain in the ass during debugging. I expect to be able to stick a "return xxxx;" anywhere I want to test something and not have the compiler crap out because I didn't deal with the overhead of commenting out the rest.

A warning might be nice, though.

A warning if anything.  I've never encountered a situation where code was made 
unreachable by accident.  I also get "unreachable code" warnings periodically, 
for code that is absolutely reachable.  I don't want my code to not compile simply 
because the compiler can't perform adequate flow analysis.

I have encountered bugs of the form:
if (cond) { /* unreachable */ }
and the cond was unintentionally always false. The last time I encountered such a bug was last week. I'm surprised your experience is so different.

It's crucial that it should never report "unreachable" if it is unsure (not even a warning). But I think conditional compilation is a huge problem -- code may be valid under different compilation conditions. I suspect that to eliminate all the false positives, it'd have to be so conservative, that it wouldn't catch any bugs.

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