<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/97313>97313</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang] Polymorhic class templates are broken in modules
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          jasiolpn
      </td>
    </tr>
</table>

<pre>
    Hello,
Looks like I've found a new bug. I've compiled fresh LLVM (last commit ae570d82e8c021f45209830db8c9c7bb79bed394) and I tried to compile following files: 

```c++
// Base.cppm
export module Mod:Base;

export template <class>
class Base
{
public:
 constexpr Base();
    constexpr virtual ~Base();
};

template <class X>
constexpr Base<X>::Base() = default;

template <class X>
constexpr Base<X>::~Base() = default;
```

```c++
// Sub.cppm
export module Mod:Sub;
import :Base;

export class Sub : public Base<int>
{
};
```

```c++
// Mod.cppm
export module Mod;
export import :Base;
export import :Sub;
```

```c++
// main.cpp
import Mod;

int main()
{
    Base<int> *b = new Sub();
    delete b;
}
```

Those files are compiled but the linker says:

```
/usr/bin/ld: CMakeFiles/vtable.dir/Sub.cppm.o:(.rodata+0xa): multiple definition of `typeinfo name for Base@Mod<int>'; CMakeFiles/vtable.dir/main.cpp.o:(.rodata+0x0): first defined here
/usr/bin/ld: CMakeFiles/vtable.dir/Sub.cppm.o:(.data.rel.ro+0x20): multiple definition of `typeinfo for Base@Mod<int>'; CMakeFiles/vtable.dir/main.cpp.o:(.data.rel.ro+0x20): first defined here
```

What is interesting is that if I make `Base` not to be template linker is doing its job successfully.

</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJysVs1u4zgTfBr60hiBpiRLOuhgJ5_xBUiABbLY3SsptmzGFCmQlCe5zLMvqJ8k3vzMDBBASBB2s1jVXWyGe68OBrEm-Y7k1ys-hKN19QP3yurerISVT_X_UWtL2BWh14Rub609edDqhHBDWHFGaO1gJHAw-B3EcEiW9cZ2vdIooXXoj3B7-9cdEFZq7kOMdSoAx7ygsmRYNpSt2yxntCpTKkXZVE0hRFEJlGmVEVYBNxJuIDiFEoJd0KG1WtvvyhygVRo9SbcwEZ1_buj0NYTt4jetsj1he9hxj0nT9920io-9dQE6KweNcGclSbcxhaS715BzWsCu1zwgkPSq0dx7kv5vShj_GsHnbcW8vx-EVg1JZyBorPEBH3s3JbOSsOr5MAB4lXBWLgxcw493Mklx_R-Kb7jBPy_sLg9Nr8ZQul3EjthA0muQ2PJBh6_B_vEz8KVRv9y9-0H8pHn3g3jGV90Y_7Slk5z7QcQ0mLq1KFEmPMt8buhF5X9bwJ2VnwvYXUQ-UPAm-lr175PquDKR1UXVXrOZAyaMqbMVL8sSrXtRNiBsK8a2xyERCb71ukSNAUFc2PpjEX8ercfpzgN3r6aNGAKEI4JW5oQOPH_yzzfufTy2H7wjbC-inL2OzoGrO37C_ThR2P4cuNCYSBWzFtslNsKyMnFW8sAJ29FHPoraQjfooHqN0eXKqKCsAdsC2dDw1KMyrQXDuzi85puS0bHEi8tYQdLdJxyWJr3Hgc4cWuV8mAighCM6_Bq58aDEoU6cHc9j9NdFf5neD0l8qPo9D_195AGUB2UCOvQhviLKQxiXW7iBjp8wChg5bygYG-LbI_Bl-s82Ux6kHfcHDw9WgB-aBr1vB62fkum4laxTWaUVX2G9LtZVmdM8y1bHGqu0KmlesmzDRCXlBrHkhWRMbHiTl8VK1YyyjBZ0vd6s8yxLZNOyTVlgk65FlhcbklHsuNKJ1ucuse6wUt4PWFdFuk5XmgvUfnzkGWs0NwfCWHzvXR3zv4nh4ElGtfLBvyAEFfT4n8G0I7-GP6x-6qw7qmYelUsVpisonD2hAWXmIeZXg9P1MYR-vIHjfDmocIyOsl30nj4vv771zj5gEwjbj8yjBSby55r9GwAA__8z4IzD">