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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Trailing return type accepted, even though it should be rejected"
href="https://llvm.org/bugs/show_bug.cgi?id=30551">30551</a>
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<th>Summary</th>
<td>Trailing return type accepted, even though it should be rejected
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>3.9
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>normal
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++14
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>michele.caini@gmail.com
</td>
</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
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<th>Classification</th>
<td>Unclassified
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<p>
<div>
<pre>The code below should be rejected, but clang accepts it:
#include <type_traits>
template<typename T>
constexpr auto check(T &&t) -> decltype(typename std::integral_constant<T,
t>::type{}) { }
int main() {
//check(42); // (1)
}
I suspect the function definition should be rejected for it is ill-formed, t
cannot be used with std::integral_constant that way.
If you uncomment (1), the compilation fails with the right error:
<span class="quote">> candidate template ignored: substitution failure [with T = int]: non-type template argument is not a constant expression</span ></pre>
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</p>
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