<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/123524>123524</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang++] if-contexpr expression aren't parsed in an immediate function context
        </td>
    </tr>

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

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

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

<pre>
    Sorry for all of these similar bugs! Just filing for now to document; I may have time to help with some PRs in a few weeks.

https://godbolt.org/z/5ejE5f1vK

The "condition of a constexpr if statement" is one of the forms that constitute a manifestly constant-evaluated expression. Since subexpressions of manifestly constant-evaluated expressions are considered to be within an _immediate function context_, the immediate-escalating expression `&fn` should be valid and allowed.

We might consider pushing an `ExpressionEvaluationContext` [here](https://github.com/llvm/llvm-project/blob/main/clang/lib/Parse/ParseExprCXX.cpp#L2207) when `CK == ConditionKind::ConstexprIf`, just prior to calling `ParseExpression()`.
</pre>
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