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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 FIXED - Friend function declarations hidden in qualifed name lookup (regression introduced by commit r350505)"
href="https://bugs.llvm.org/show_bug.cgi?id=42513">bug 42513</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>REOPENED
</td>
<td>RESOLVED
</td>
</tr>
<tr>
<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>FIXED
</td>
</tr></table>
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<div>
<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - Friend function declarations hidden in qualifed name lookup (regression introduced by commit r350505)"
href="https://bugs.llvm.org/show_bug.cgi?id=42513#c4">Comment # 4</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - Friend function declarations hidden in qualifed name lookup (regression introduced by commit r350505)"
href="https://bugs.llvm.org/show_bug.cgi?id=42513">bug 42513</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>The new testcase is also rejected by GCC 10 onwards. But it accepts with this
change:
- if (auto i = GetInstance<X1>())
+ if (auto i = GetInstanceImpl((X1*)nullptr)())
whereas Clang rejects, saying:
<source>:59:16: error: function 'GetInstanceImpl' with deduced return type
cannot be used before it is defined
if (auto i = GetInstanceImpl((X1*)nullptr)())
^
... which gives a suggestion as to what's going wrong. Here's a reduced
testcase:
template<typename X> struct T { friend auto f(X*) {} };
struct X1 { friend auto f(X1*); };
template struct T<X1>;
void g() { f((X1*)nullptr); }
It turns out that when looking for a definition to instantiate in order to
resolve an undeduced return type, we didn't check for the case of a function
for which a different redeclaration was instantiated from a friend definition.
Fixed in dd8297b0669f8e69b03ba40171b195b5acf0f963.</pre>
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