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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Template argument looses 'pointer' when instantiating static"
href="https://bugs.llvm.org/show_bug.cgi?id=37824">37824</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Template argument looses 'pointer' when instantiating static
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>6.0
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Windows NT
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>-New Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>jvapen@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Command line:
-------------
cl.exe /EHsc t.cpp /std:c++17
llvm_6_0_0\bin\clang-cl.exe -fms-compatibility-version=19.11 -ferror-limit=2
/EHsc t.cpp /std:c++17 -w
Full file (t.cpp):
------------------
// This compiles fine without c++17
#include <atlbase.h>
#include <atlwin.h>
int main()
{
return 0;
}
Reduced file (t.cpp):
---------------------
#include <guiddef.h>
struct __declspec(uuid("B2D0778B-AC99-4c58-A5C8-E7724E5316B5")) A {
long GetTypeInfo();
};
template <class T, const GUID *piid = &__uuidof(T)> struct B {
virtual long GetTypeInfo() { return _tih.GetTypeInfo(); }
static A _tih;
};
template <class T, const GUID *piid> A B<T, piid>::_tih = {};
struct D : public B<A> {
D() {}
};
error:
------
t.cpp(13,45): error: value of type 'const _GUID' is not implicitly convertible
to 'const GUID *'
(aka 'const _GUID *')
template <class T, const GUID *piid> A B<T, piid>::_tih = {};
^~~~
t.cpp(8,39): note: in instantiation of static data member 'B<A,
__uuidof(A)>::_tih' requested here
virtual long GetTypeInfo() { return _tih.GetTypeInfo(); }
^
t.cpp(16,3): note: in instantiation of member function 'B<A,
__uuidof(A)>::GetTypeInfo' requested here
D() {}
^
On changing: &__uuidof(T) into &(&__uuidof(T)), one gets the error:
t.cpp(7,39): error: cannot take the address of an rvalue of type 'const _GUID
*'
This seems to indicate that on class initialization the type is correctly known
by Clang-cl. However, as soon as _tih gets initialized, it looks like the
compiler no longer knows its dealing with a pointer.
Same bug was already reported to microsoft a while ago:
<a href="https://developercommunity.visualstudio.com/content/problem/168272/headers-incompatible-with-llvm-vs2014-toolset-c17.html">https://developercommunity.visualstudio.com/content/problem/168272/headers-incompatible-with-llvm-vs2014-toolset-c17.html</a></pre>
</div>
</p>
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