<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/152282>152282</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [DebugInfo] Unexpanded parameter pack variables have misleading debug-info
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            lldb,
            debuginfo
      </td>
    </tr>

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

    <tr>
      <th>Reporter</th>
      <td>
          Michael137
      </td>
    </tr>
</table>

<pre>
    Was looking at what the debug-info looks like for https://github.com/llvm/llvm-project/pull/121417.

Take this modified example from p1061r10:
```
struct C { int x = 1, y = 2, z = 3; };

template <class T>
void now_i_know_my() {
  auto [a, b, c] = C();
 auto [d, ...e] = C();
  auto [...f, g] = C();
  auto [h, i, j, ...k] = C();
  __builtin_debugtrap();
}

int main() {
 now_i_know_my<int>();
    return 0;
}
```

```
clang++ pack.cpp -g
```

Then in LLDB:
```
$ lldb a.out -o run -o v
(lldb) v
(int) a = 1
(int) b = 2
(int) c = 3
(int) d = 1
(int) e = 2
(int) f = 1
(int) g = 3
(int) h = 1
(int) i = 2
(int) j = 3
```

Note how the unexpanded parameter packs (e.g., `e`, `f`) are represented are showing as `int`s instead of packs.

Here's a dwarfdump snippet
```
0x00000058: DW_TAG_variable
                  DW_AT_location        (DW_OP_fbreg -16, DW_OP_plus_uconst 0x8)
                  DW_AT_name    ("c")
 DW_AT_type    (0x00000000000000e7 "int")

0x00000065: DW_TAG_variable
                  DW_AT_location        (DW_OP_breg31 WSP+32)
                  DW_AT_name    ("d")
 DW_AT_type    (0x00000000000000e7 "int")

0x00000070: DW_TAG_variable
                  DW_AT_location        (DW_OP_breg31 WSP+32, DW_OP_plus_uconst 0x4)
                  DW_AT_name    ("e")
 DW_AT_type    (0x00000000000000e7 "int")
```

Symptoms look similar to what happens with template parameter packs https://github.com/llvm/llvm-project/issues/24643
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJy0Vt1u6zYMfhrlhqghyz9JLnyR1Ms24Gw7wOnQS0O2aVuNLBmSnLR7-kGO0yY9KYZuZ0YQSdRHUh9J_XBrRasQM5JsSZIv-Og6bbLfRNVxlGG0XJS6fskeuQWp9V6oFriDY8cduA6hxnJs74Rq9DRtQYo9QqMNdM4NlkQbwnaE7VrhurEMKt0TtpPycG7uBqOfsHKE7YZRSsJ2IQvjcBkQuiF088D3CK4TFnpdi0ZgDfjM-0EiNEb3MIQ0DU1IvR-6ISmdf3RjnRkrB_dAllsQysEzkCiHkLB7eJm6zHf_mroRibZAljmJtie_DvtBcodAovtKcmvhgUQ_Ebo5aFGD0sdCFHvf9C-ErQhbezeEbgD46DSQZMu99dL_VSTJJy_3J-jJySuw9pggCPA27BUXBEHjoe0_4DoPEv7vaba8_0CjKMpRSCdUMWXRGT5cAnw8pmD46PVcqGum10GI7oVyPkRXHgAMutEooFcmL9L0blhJrlrCtoRtYeDVPqiGAe7a75UeOlQgFHz5km-_Tz5hMUhZl8ADPTq402BG5ZvDNLnyc57KPPRLZ2vgc4Vcysq5VC5l1Vwzl7L6hi7e0G1u4Nob9robOHHD3tOb7nWAftcOodPHaZeOCp8HrmqsYeCG9-jQTPG1QNgKgzbwpUJSil7_1G2m7hq4QTA4GLSoHNbT2Hb6OJ0E1iP9UlJqQSjrkNegm5PteQ__ggYJW1rgUB-5aeqxH8AqMQzo3q2bPtPpS1Yk2kD-WDxsfi4O3AheSpwr6vrLH4vNQyF1xZ3Q6iwlbJU_Fn98LZrSYAt3YepJnUSDHG0xVlpZB_R5qtaPDSve42yQMFYRxmb8adq9DOfp89LPHy6BMDZlada54JcmP4ifpxeF8PjtK2HbiH2GTP2jyCzp_0Xmdsriz7DE_8byek99e-kHp_vTTQhW9EJyA06frsOODwMqC0fhOni9QN7vt09fi8LaES1hOxancbSos6heR2u-wCxcJnG8jMJVuuiyKIzXtIlZFHFaLZO4ihMaJjUvlyln6zRdiIxRltAVTek6WsdpwFiCHEMe1axcJSEjMcWeCxn4BQTatIvJdRYmjK3YQvISpZ2eCYydDlCfIl9J_vbwTwAvSfKFySYK5dhaElMprLNvNp1wcnps5F7rV6-V5PDnRwcUnAvKQscPCL2wEnntD5-3p8diNDL794GdCR4y9ncAAAD__2ENg5I">