[PATCH] templated static_assert

[Richard Smith]

I don't think the diagnostic wording is right: 'template<typename T>' is
not "a template declaration" in itself. A better model for the diagnostic
might be this:

<stdin>:1:34: error: a typedef cannot be a template
template<typename T> typedef int n;
                                 ^

... so "a static_assert declaration cannot be a template" (or "[...] cannot
be templated" or similar).

Also, we should use the same diagnostic for the member-declaration and the
non-member-declaration cases. (Right now, the non-member case gives a
useless "C++ requires a type specifier" diagnostic.)


On Mon, Aug 4, 2014 at 11:23 AM, Aaron Ballman <aaron at aaronballman.com>
wrote:

> According to [temp]p1, a static_assert cannot be templated (we have a
> FIXME in the code about this as well). This patch emits a diagnostic
> turning this into an error instead of silently accepting the template
> and doing the wrong thing. Eg)
>
> struct S {
>   template <typename Ty = char>
>   static_assert(sizeof(Ty) != 1, "Not a char");
> };
>
> This code currently compiles without diagnosing, but the static_assert
> does not result in a diagnostic as you would expect. With this patch,
> the code now emits a diagnostic on the template declaration.
>
> ~Aaron
>
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