gcc doesn't like foreach with const-ref containers

[Christian Ehrlicher]

Andreas Pakulat schrieb:
> On 05.09.07 19:17:20, Andreas Pakulat wrote:
>> On 05.09.07 06:30:19, Christian Ehrlicher wrote:
>>> Andreas Pakulat schrieb:
>>>> Hi,
>>>> while compiling kdevelop I got an error on some code in its language
>>>> support which compiles fine with gcc 4.2 on linux. (I'm using mingw
>>>> suite 5.1.3, i.e. gcc 3.4.5 on win32).
>>>> The problem seems to be that findDeclarationsInternal on line 107 in
>>>> kdevelop/languages/cpp/duchainbuilder/cppducontext.h has a
>>>> const-reference to a QList as parameter. The error (log attached)
>>>> indicates that foreach() can't handle such a const-ref list, while doing
>>>> the "standard" for( foo::const_iterator it = list.begin()... thing works
>>>> fine.
>>>> Does anybody know a "better" solution than to use an iterator-loop, or a
>>>> reason why this is. Is it maybe a gcc bug?
>>> Plz make a testcase for this so I can take a look
>> Seems like templates have to be involved as well. See the attached
>> main.cpp (just use qmake -project;qmake;make to build).
>>
>> As soon as you remove the template from MyTest it compiles fine. Else I
>> get that error.
> 
> And here's the actual file :)
> 
Thx, I can reproduce this error.

I wonder why this works on linux. A quick solution would be to remove 
the reference. It's implicit shared so it doesn't matter if you pass a 
reference or a copy here. And if this breaks BC, just use an internal copy:

void foo(const QList<MyClass>& l_)
{
   const QList<MyClass> l(l_);
   foreach(const MyClass& c, l)
     ...
}


Christian
btw: cc to thiago because he loves such things (at least I hope he does 
;-) )

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