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<div class="moz-cite-prefix">Hmm, if I do this it gives me another
error:<br>
<br>
test.cpp:15:42: error: 'SmartPtrType' following the 'template'
keyword does not refer to a template<br>
~SmartUnion()
{m_sptr.SmartPtrType<T>::~SmartPtrType<T>(); }<br>
<br>
Again, g++ takes it without complaining.<br>
<br>
Since I noticed that my original attachment got scrubbed I am
pasting the modified test program directly. Perhaps the context
will help to sort things out:<br>
<br>
#include <memory><br>
#include <string><br>
using namespace std;<br>
<br>
//comment this in to see the compiler error<br>
#define show_compiler_error 1<br>
<br>
template<typename T, template<class> class SmartPtrType =
shared_ptr> <br>
struct SmartUnion<br>
{<br>
SmartUnion() {new(&m_sptr) SmartPtrType<T>();}<br>
<br>
<br>
#ifdef show_compiler_error<br>
~SmartUnion()
{m_sptr.SmartPtrType<T>::~SmartPtrType<T>(); }<br>
#else <br>
typedef SmartPtrType<T> smartptr_type;<br>
~SmartUnion() {m_sptr.smartptr_type::~smartptr_type(); }<br>
#endif<br>
<br>
union { <br>
SmartPtrType<T> m_sptr;<br>
T * m_ptr;<br>
};<br>
<br>
};<br>
<br>
using namespace std;<br>
int main()<br>
{<br>
SmartUnion<string,shared_ptr> smu;<br>
<br>
return 0;<br>
}<br>
<br>
<br>
Am 08.10.2013 20:08, schrieb Richard Smith:<br>
</div>
<blockquote
cite="mid:CAOfiQqn4hOGZWupcuCOZDT00MViE5TjpxBJRte4rMzbiXYrdTA@mail.gmail.com"
type="cite">
<div dir="ltr">You need to write
<div><br>
</div>
<div> m_sptr.SmartPtrType<T>::~SmartPtrType<b><T></b>();<br>
<div class="gmail_extra"><br>
</div>
<div class="gmail_extra">Per 3.4.3/6, "in a qualified-id of
the form nested-name-specifier[opt] class-name::~class-name,
the second class-name is looked up in the same scope as the
first". So you can't use the injected-class-name after the
~, because it's not visible.</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Tue, Oct 8, 2013 at 10:05 AM,
Daniel Schwalbe <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:dansch491@gmail.com" target="_blank">dansch491@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
<div>When I add the 'template' keyword as suggested
clang gives me the very same error. g++ still eats
it without problem.<br>
<br>
Am 08.10.2013 18:23, schrieb David Blaikie:<br>
</div>
<div>
<div class="h5">
<blockquote type="cite">
<div dir="ltr"><br>
<div class="gmail_extra"><br>
<br>
<div class="gmail_quote">On Tue, Oct 8, 2013
at 8:36 AM, Daniel Schwalbe <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:dansch491@gmail.com"
target="_blank">dansch491@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Hi,<br>
<br>
I don't know if I encountered a compiler
bug in clang 3.3 or if this is one of
the many subtle c++ exceptional cases:<br>
<br>
When I try to compile the attached file
(using: clang++ -std=c++11 test.cpp) I
receive a compiler error:<br>
<br>
"test.cpp:15:42: error: identifier
'SmartPtrType' in object destruction
expression does not name a type<br>
~SmartUnion()
{m_sptr.SmartPtrType<T>::~SmartPtrType();
}"<br>
<br>
g++ compiles the file without problem.<br>
<br>
clang compiles it, too, if I explicitly
introduce a typedef for
SmartPtrType<T> and call this
typedef name instead:<br>
<br>
typedef SmartPtrType<T>
smartptr_type;<br>
~SmartUnion()
{m_sptr.smartptr_type::~smartptr_type();
}<br>
<br>
Is this a subtle language feature or a
compiler bug?</blockquote>
<div><br>
</div>
<div>I believe this is a language feature
because the expression is ambiguous if
m_sptr is type dependent (which I assume
it is)<br>
<br>
The other solution, rather than
introducing a typedef, is to use the
'template' keyword:<br>
<br>
~SmartUnion() {m_sptr.template
SmartPtrType<T>::~SmartPtrType();
}<br>
</div>
<div> </div>
<blockquote class="gmail_quote"
style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><span><font
color="#888888"><br>
<br>
Daniel<br>
<br>
<br>
<br>
</font></span><br>
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<br>
</blockquote>
</div>
<br>
</div>
</div>
</blockquote>
<br>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</div>
</blockquote>
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