[cfe-commits] [patch] pr9786 assert-on-invalid non-final parameter packs

[Douglas Gregor]

On Oct 13, 2011, at 10:09 PM, David Blaikie wrote:

> [& of course I forget to include the patch. Attached now]
> 
> On Thu, Oct 13, 2011 at 10:09 PM, David Blaikie <dblaikie at gmail.com> wrote:
> From the bug:
> 
> template<int ...Values, int After> struct X0nt;
> X0nt<42> f();
> 
> Causes clang to fail an assertion (SemaTemplate.cpp:4868 - "Converted template argument list is too short!"). This fix causes CheckTemplateArgumentList to fail if there are parameter packs anywhere other than the last argument in a non-partial application of the template arguments (partial applications include function templates for which non-final parameter packs may be valid. This change does not regress that behavior as far as I know/as far as the test cases already cover it).
> 
> I've included a test for this fix.
> 
> As an added bonus, I've also fixed a minor quirk in the output of the diagnostic that appears here ("template parameter pack must be the last template parameter") - currently/without my patch, Clang produces this diagnostic for every parameter after a parameter pack. So in the case of "template<typename ...A, typename B, typename C> struct foo;" the error is emitted twice (though, strangely, the second type it is produced it does not provide the context/line location, though the line/col numbers are the same & still correct). I've fixed that issue & modified a test case to catch it too.
> 
> Let me know if this looks good & I'll check it in,

LGTM!

	- Doug
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