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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - False acceptance of ambiguity in case of multiple inheritance and spaceship operator"
href="https://bugs.llvm.org/show_bug.cgi?id=52186">52186</a>
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<th>Summary</th>
<td>False acceptance of ambiguity in case of multiple inheritance and spaceship operator
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>12.0
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Windows NT
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>C++2b
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>fchelnokov@gmail.com
</td>
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<th>CC</th>
<td>blitzrakete@gmail.com, erik.pilkington@gmail.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk
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<p>
<div>
<pre>The program as follows is accepted in Clang:
```
#include <compare>
struct A {
auto operator <=>(const A&) const = default;
bool operator <(const A&) const = default;
};
struct B {
auto operator <=>(const B&) const = default;
};
struct C : A, B {};
int main() {
C c;
return c < c;
}
```
Demo: <a href="https://gcc.godbolt.org/z/5YzvqT3aK">https://gcc.godbolt.org/z/5YzvqT3aK</a>
But it shall be an error (as in GCC) due to ambiguity. A more detailed
explanation can be found in this answer:
<a href="https://stackoverflow.com/a/69245639/7325599">https://stackoverflow.com/a/69245639/7325599</a></pre>
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</p>
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