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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - cannot inherit priority_queue's constructors due to enable_if in some cases."
href="https://llvm.org/bugs/show_bug.cgi?id=26217">26217</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>cannot inherit priority_queue's constructors due to enable_if in some cases.
</td>
</tr>
<tr>
<th>Product</th>
<td>libc++
</td>
</tr>
<tr>
<th>Version</th>
<td>3.7
</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>All Bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>koolcoy@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, mclow.lists@gmail.com
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>The following code won't compile against libc++ with clang++-3.7 (it compiles
as expected against libstdc++ with clang++-3.7 or g++-5). If data member Foo::f
is moved to a function local scope or to global scope, the code also compiles
#include <queue>
template<typename T, typename Container = std::vector<T>,
typename Compare = std::less<T>>
class PriorityQueue : public std::priority_queue<T, Container, Compare> {
using Parent = std::priority_queue<T, Container, Compare>;
public:
using std::priority_queue<T, Container, Compare>::priority_queue;
void clear() {
this->c.clear();
}
};
struct Foo {
struct Node {
int distance;
};
struct Compare {
bool operator () (Node* a, Node* b) const {
return a->distance < b->distance;
}
};
PriorityQueue<Node*, std::vector<Node*>, Compare> f;
};
void f() {
Foo x;
};
error message:
In file included from t.cpp:1:
/opt/local/libexec/llvm-3.7/bin/../include/c++/v1/queue:450:43: error: no type
named 'type' in 'std::__1::enable_if<false, void>'; 'enable_if' cannot be
used to disable this declaration
typename enable_if<uses_allocator<container_type,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
t.cpp:8:52: note: in instantiation of member function
'std::__1::priority_queue<Foo::Node *, std::__1::vector<Foo::Node *,
std::__1::allocator<Foo::Node *> >, Foo::Compare>::priority_queue'
requested here
using std::priority_queue<T, Container, Compare>::priority_queue;
^
t.cpp:5:7: note: while substituting deduced template arguments into function
template 'PriorityQueue' [with _Alloc = PriorityQueue<Foo::Node *,
std::__1::vector<Foo::Node *, std::__1::allocator<Foo::Node *> >,
Foo::Compare>]
class PriorityQueue : public std::priority_queue<T, Container, Compare> {
^
In file included from t.cpp:1:
/opt/local/libexec/llvm-3.7/bin/../include/c++/v1/queue:450:43: error: no type
named 'type' in 'std::__1::enable_if<false, void>'; 'enable_if' cannot be
used to disable this declaration
typename enable_if<uses_allocator<container_type,
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
2 errors generated.</pre>
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