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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Template functions see friendship as inherited"
href="http://llvm.org/bugs/show_bug.cgi?id=16449">16449</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Template functions see friendship as inherited
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>3.3
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>C++
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>w.shane.grant@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvmbugs@cs.uiuc.edu
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Template functions that are friends of a class bypass access control for
derived classes.
----------
template <class T> T&& declval();
template <class T>
auto foo() -> decltype(declval<T&>().bar()) {}
class Base
{
private:
template <class T>
friend auto foo() -> decltype(declval<T&>().bar());
void bar(){}
};
class Derived : public Base {};
int main()
{
foo<Derived>();
}
-----------
bar should be private in Derived but the friend declaration in Base is allowing
foo to access it, preventing compilation from failing. Here's another very
similar example:
---------
template <class T>
void foo(T&&t)
{
t.bar();
}
class Base
{
private:
template <class T>
friend void foo(T&&);
void bar(){}
};
class Derived : public Base {};
int main()
{
foo(Derived());
}
--------
Derived gets the ability to call bar() only inside of the template function
foo.
Tested on clang version 3.3 (trunk 178896) (llvm/trunk 178895) and clang
version 3.4 (trunk 184863).</pre>
</div>
</p>
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