<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/140773>140773</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Failure to deduce nested template arguments
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

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

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

<pre>
    After https://github.com/llvm/llvm-project/pull/138122, clang++ is failing to deduce a template parameter when instantiating a templated class object inside the ctor of another templated class object. In this case, we make an assignment to a `static constexpr` typed variable (ie we are not initializing a `static inline auto` variable).

@dty2 - could you help take a look into this and help determine whether this is an unintended consequence of https://github.com/llvm/llvm-project/pull/138122?

Attached is a reproducer that emulates this new compilation failure:
[startup-random-867b56.zip](https://github.com/user-attachments/files/20353121/startup-random-867b56.zip)

</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJykk8GO4zYMhp9GvhAJZNpO4oMPmV0Y6GPQFhOrK0uuRM00-_SF7G6nly1QLGDAB1I_P_2_SCnZp2ceVPemuq8VZVlCHL5Qci9fTcG8hvtDOMIisiXV3BWOCsenlSVP5zmsCkfn3n_8TlsMv_MsCsctO6dwrJtbjajwC8yO_FPhm8I3sAkeZJ31T5AAhk2eGQiE182RMGwUaeUy92NhD9YnIS-WpJz47DNFNCUIUxla2qxhkIVhlhAhPIB8kIXjT06c4TcPstgEMyUukB8MK31jIA-HNSt7KYwE6qKTkNgZ5uCT8J9bVBcN8trYwDtFS5NjUHizXGQoMvhQoKxYcvb7gf6pYr2znoGyhKLzQ0Fhf1b6Xr5WG3khnGAO2Rl4hQwLuw1kJwQXwjewXsJxBfLmKJti3Fq0PxY-bl_qewtkb72wN8WJ4BP_kdnPXKz6xYSb8aC-i9C8sNnnQeQthpJugSABXnOJIR1Inj9gDutmHYkNfn8TOXKB0HfVvSWhKHk7RfImrKfb5Tp1l_N3u6nuq8LbfxDnxPFEO0pJMCkcH9Zx-aNuuqbGWuH4c33slb5XZmhM3_RU8VBf2-v10l7wUi3DtdNcd3gzUz11Pd5mM3X0aFrdtzessa3sgBo73aGub7XGy7k1uuZOPxBr7Ou6V63mlaw7F0_PIT4rm1LmoW719dpUjiZ2aV9KxOLSXlWIZUfjsAcx5WdSrXY2SfqUESuOh_Ew8l_L5TmV1__PhlF85t2ZKkc3_O_sd57i5t_A7wP-FQAA__9OCm8V">