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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 --- - this pointer isn't qualified within decltype() when used in member function declaration with late specified return type"
href="http://llvm.org/bugs/show_bug.cgi?id=16243">16243</a>
</td>
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<tr>
<th>Summary</th>
<td>this pointer isn't qualified within decltype() when used in member function declaration with late specified return type
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</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++11
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>mitchnull+llvm@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>Created <span class=""><a href="attachment.cgi?id=10636" name="attach_10636" title="test program showing the failure">attachment 10636</a> <a href="attachment.cgi?id=10636&action=edit" title="test program showing the failure">[details]</a></span>
test program showing the failure
The explicit 'this' pointer in member function declaration with late specified
return type using decltype is not const-qualified if the member function is
declared 'const' resulting in wrong return type.
Example:
template <typename T>
struct DecltypeConstThis {
void f() {}
T f() const { return T{}; }
auto g() -> decltype(this->f()) { return f(); }
auto g() const -> decltype(this->f()) { return f(); } // apparently
'this' is not const within the decltype() here
};
int main() {
DecltypeConstThis<int> d;
const DecltypeConstThis<int> &cd = d;
d.g();
cd.g(); // fails
return 0;
}
compilation error:
[mitch@deneb src]$ clang++ -std=c++11 -o decltype-const-this
decltype-const-this.cpp
decltype-const-this.cpp:8:47: error: void function 'g' should not return a
value
[-Wreturn-type]
auto g() const -> decltype(this->f()) { return f(); } // apparently
'this' is...
^ ~~~
decltype-const-this.cpp:17:8: note: in instantiation of member function
'DecltypeConstThis<int>::g' requested here
cd.g(); // fails
The same code works as expected with implicit 'this':
template <typename T>
struct DecltypeConstThis {
void f() {}
T f() const { return T{}; }
auto g() -> decltype(f()) { return f(); }
auto g() const -> decltype(f()) { return f(); } // decltype() correctly
picks 'f() const' here
};
int main() {
DecltypeConstThis<int> d;
const DecltypeConstThis<int> &cd = d;
d.g();
cd.g();
return 0;
}
(ps: gcc-4.8 requires the explicit this-> here, filing a bug report that way,
too)</pre>
</div>
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