[clang] [clang] CTAD: implement the missing IsDeducible constraint for alias templates (PR #89358)

[Haojian Wu via cfe-commits]

================
@@ -868,13 +868,7 @@ <h2 id="cxx20">C++20 implementation status</h2>
     <tr>
       <td>Class template argument deduction for alias templates</td>
       <td><a href="https://wg21.link/p1814r0">P1814R0</a></td>
-      <td class="partial" align="center">
-        <details>
-          <summary>Clang 19 (Partial)</summary>
-          The associated constraints (over.match.class.deduct#3.3) for the
-          synthesized deduction guides are not yet implemented.
-        </details>
-      </td>
+      <td class="partial" align="center">Clang 19 (Partial)</td>
----------------
hokein wrote:

With this patch, this feature is completed. However, I suspect that there maybe issues, and it needs some time to be productized. Therefore, I hesitate to say that it is "ready" (although I'm not sure what the common practice is).

https://github.com/llvm/llvm-project/pull/89358