[Issue 2423] New: Erroneous unreachable statement warning

[Lars Ivar Igesund]

Don wrote:

> d-bugmail at puremagic.com wrote:
>> http://d.puremagic.com/issues/show_bug.cgi?id=2423
>> 
>>            Summary: Erroneous unreachable statement warning
>>            Product: D
>>            Version: 1.035
>>           Platform: Other
>>         OS/Version: All
>>             Status: NEW
>>           Keywords: diagnostic
>>           Severity: regression
>>           Priority: P2
>>          Component: DMD
>>         AssignedTo: bugzilla at digitalmars.com
>>         ReportedBy: larsivar at igesund.net
>> 
>> 
>> Consider the following function:
>> 
>> void foo() {
>> 
>>     do {
>>         if (false)
>>             return 1;
>>     } while (true);
>> }
>> 
>> Compiling with -w, results in
>> 
>> warning - whiletrue.d(6): Error: statement is not reachable
>> 
>> Minimized from a module in Tango, meaning Tango does not compile with
>> warnings on.
>> 
>> This regression was introduced in DMD 1.032.
>> 
>> 
> Why is that wrong? "return 1" looks unreachable to me.

It is 

while(true)

that is line 6 (you can move the while a few lines down to see that it isn't
just a line number error). The return makes the statement on that line
("true" I assume) unreachable, which is correct without the conditional. So
it is the presence of the if (false) that makes this an error.

-- 
Lars Ivar Igesund
blog at http://larsivi.net
DSource, #d.tango & #D: larsivi
Dancing the Tango