[A minor correction to the patch. Sorry. This is final.]<br><br><div class="gmail_quote">On Sat, Aug 27, 2011 at 2:59 PM, Larisse Voufo <span dir="ltr"><<a href="mailto:lvoufo@cs.indiana.edu">lvoufo@cs.indiana.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;">By the way, here is a sample before and after "picture" of error message for explicit instantiation failure:<br>
<br>---------------------------<br>Before<br>---------------------------<br>$ ~/llvm/Debug+Asserts/bin/clang++ test.cpp -o test<br>
test.cpp:7:15: error: explicit instantiation of 'func' does not refer to a function template, member function, member class, or static<br> data member<br>template void func<int>(short); // expected-error {{explicit instantiation of 'func' does not refer to a function template}}<br>
^<br>1 error generated.<br><br><br>
---------------------------<br>
After<br>
---------------------------<br>$ ~/llvm/Debug+Asserts/bin/clang++ test.cpp -o test<br>test.cpp:7:15: error: explicit instantiation of 'func' does not refer to a function template, member function, member class, or static<br>
data member<br>template void func<int>(short); // expected-error {{explicit instantiation of 'func' does not refer to a function template}}<br> ^<br>test.cpp:2:6: note: candidate template ignored: failed template argument deduction<br>
void func(T) { }<br> ^<br>1 error generated.<br><br><br>
-----------------------------------------------------------------------------------------<br>
The code the the compiler generates the above errors for follows:<br>
-----------------------------------------------------------------------------------------<br>template<typename T><br>void func(T) { }<br><br>template void func(char);<br>template void func(float); <br>template void func(int);<br>
template void func<int>(short); <br><br>int main(int argc, char **argv) <br>{ <br> return 0;<br>}<br><br>Thanks,<br><font color="#888888">-- Larisse.</font><div><div></div><div class="h5"><br><br><br><div class="gmail_quote">
On Sat, Aug 27, 2011 at 2:46 PM, Larisse Voufo <span dir="ltr"><<a href="mailto:lvoufo@cs.indiana.edu" target="_blank">lvoufo@cs.indiana.edu</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Attached is a patch I just made to address the issue below. <br>It basically adds local implementation in SemaTemplate.cpp and updates two regression tests.<br>
I hope I applied the LLVM code standard well enough.<br><br>Basically, to resolve this issue, I had to adapt a reasoning similar to that used for overload resolution (in SemaOverload.cpp). However, I resisted to reuse the implementation directly, as there must be a reason why the vast experience of clang developers (mine being minuscule in comparison) had not done that themselves yet. :) <br>
In fact, looking at the C++ Standard, [over.match] precisely, it appears that the functions that cause explicit instantiations or specializations to cause the template argument deduction failures are not to be considered "candidate functions". <br>
Is that correct? If so, does that explain why I shouldn't reuse the implementation directly and simply do what I provide in the patch? <br><br>One more thing: For now, the patch is reusing the same diagnosis messages as in SemaOverload.cpp, precisely DiagnoseBadDeduction(), with diagnosis id starting with note_ovl_candidate_*. Should I create entirely new diagnosis instead? If so, what about <br>
should I express these replacements? <br><div><br>Please let me know what you think.<br><br>Thanks,<br>-- Larisse.<br><br><br><br></div><div><div></div><div><div class="gmail_quote">On Mon, May 9, 2011 at 12:00 PM, Douglas Gregor <span dir="ltr"><<a href="mailto:dgregor@apple.com" target="_blank">dgregor@apple.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div></div><div><br>
On May 9, 2011, at 6:13 AM, Larisse Voufo wrote:<br>
<br>
> The current code base, under Sema::ActOnExplicitInstantiation and Sema::CheckFunctionTemplateSpecialization (in SemaTemplate.cpp), looses information about why a given template argument deduction fails.<br>
> I need that to not be the case for better diagnoses in concepts-enabled programs.<br>
> I was wondering what the best approach would be at the moment, depending on when the Clang community intends to review that part of the implementation.<br>
> Should I go ahead and modify my off-main-branch concepts implementation, or<br>
> should I make the change directly into clang's main branch, or<br>
> should I simply give it a moment until that part is reviewed? If so, about how long should I wait.<br>
><br>
> I find it'd be more beneficial, if I were to do it myself, if I made the changes as globally as possible rather than just within my concepts implementation.<br>
<br>
<br>
</div></div>I suggest implementing it for inclusion in Clang's main branch, and submitting a patch to cfe-commits. That way, everyone can benefit from this work immediately, and it'll just be That Much Cooler when concepts are involved.<br>
<br>
- Doug<br>
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