[cfe-dev] Should DiffTemplate be able to handle Integral args?

[Richard Trieu]

On Fri, Oct 19, 2012 at 1:56 PM, Matthew Curtis <mcurtis at codeaurora.org>wrote:

>  Hello all,
>
> I'm seeing an assert when compiling code like this:
>
> template <int i> struct X { };
> void f(X<8> x) {
>   X<7> y;
>   y = x;
> }
>
>
> DiffTemplate/GetExpr (in ASTDiagnostic.cpp) assumes that the non-type args
> are expressions:
>
> void DiffTemplate() {
>
>   // Handle Expressions
>   if (NonTypeTemplateParmDecl *DefaultNTTPD =
>       dyn_cast<NonTypeTemplateParmDecl>(ParamND)) {
>     Expr *FromExpr, *ToExpr;
>     GetExpr(FromIter, DefaultNTTPD, FromExpr);
>     GetExpr(ToIter, DefaultNTTPD, ToExpr);
>   }
>
> }
>
> void GetExpr(const TSTiterator &Iter, ) {
>
>   if (!Iter.isEnd())
>     ArgExpr = Iter->getAsExpr();
>
> }
>
>
> But in some cases they are integral values (e.g. Iter->getKind() ==
> TemplateArgument::Integral). As a result, an assertion inside
> Iter->getAsExpr() fails.
>
> Is DiffTemplate broken or should the integral arg never have found it's
> way to it?
>
> BTW, I modified GetExpr to create an Expr from the Integral arg and that
> seemed to work, but I'm not sure if that's the right thing to do.
>
> Cheers,
> Matthew C.
>
>
>
> --
> Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
>
>
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>
>
This was reported in PR14015.  I have created a patch to fixed this issue.
 See the posting below on cfe-commits.

http://lists.cs.uiuc.edu/pipermail/cfe-commits/Week-of-Mon-20121008/065792.html
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