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    <body><span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span> changed
          <a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED INVALID - decltype((x)) inside lambda is considered odr-use if x is captured"
   href="https://bugs.llvm.org/show_bug.cgi?id=35423">bug 35423</a>
          <br>
             <table border="1" cellspacing="0" cellpadding="8">
          <tr>
            <th>What</th>
            <th>Removed</th>
            <th>Added</th>
          </tr>

         <tr>
           <td style="text-align:right;">Status</td>
           <td>NEW
           </td>
           <td>RESOLVED
           </td>
         </tr>

         <tr>
           <td style="text-align:right;">Resolution</td>
           <td>---
           </td>
           <td>INVALID
           </td>
         </tr>

         <tr>
           <td style="text-align:right;">CC</td>
           <td>
                
           </td>
           <td>richard-llvm@metafoo.co.uk
           </td>
         </tr></table>
      <p>
        <div>
            <b><a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED INVALID - decltype((x)) inside lambda is considered odr-use if x is captured"
   href="https://bugs.llvm.org/show_bug.cgi?id=35423#c2">Comment # 2</a>
              on <a class="bz_bug_link 
          bz_status_RESOLVED  bz_closed"
   title="RESOLVED INVALID - decltype((x)) inside lambda is considered odr-use if x is captured"
   href="https://bugs.llvm.org/show_bug.cgi?id=35423">bug 35423</a>
              from <span class="vcard"><a class="email" href="mailto:richard-llvm@metafoo.co.uk" title="Richard Smith <richard-llvm@metafoo.co.uk>"> <span class="fn">Richard Smith</span></a>
</span></b>
        <pre>Prior to P0588R1:

[expr.prim.lambda.capture]/14:

"Every occurrence of decltype((x)) where x is a possibly parenthesized
id-expression that names an entity of automatic storage duration is treated as
if x were transformed into an access to a corresponding data member of the
closure type that would have been declared if x were an odr-use of the denoted
entity."

This is clear that Clang is correct that B and D give decltype((x)) as const
int&, not int&. But the types of A and C are unclear.

After P0588R1, the wording is a bit clearer:

[expr.prim.id.unqual]/1:

"If the entity is a local entity and naming it from outside of an unevaluated
operand within the declarative region where the unqualified-id appears would
result in some intervening lambda-expression capturing it by copy, the type of
the expression is the type of a class member access expression ([expr.ref])
naming the non-static data member that would be declared for such a capture in
the closure object of the innermost such intervening lambda-expression. [ Note:
If that lambda-expression is not declared mutable, the type of such an
identifier will typically be const qualified. ]"

Here we see that A and C should have type int& and B and D should have type
const int&.</pre>
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