[clang] [clang] Enable C++17 relaxed template template argument matching by default (PR #89807)

[Matheus Izvekov via cfe-commits]

mizvekov wrote:

> I think I prefer pretty fine-grained ones TBH, it makes our deprecation warnings more valuable. In a perfect world, it would change every release of the compiler so that folks would be frequently reminded of it, but it isn't a perfect world :)

I meant something fine grained, but generic, like `-Wno-deprecated-flag=-fno-relaxed-template-template-args`.
We have something similar for generic warnings.
That would probably take a little longer to get everyone onboard the design, and may lack other motivators presently.
 
> Is doing so much of a task? I would expect it to be like other diagnostics and take roughly the same amount of time as reverting the negative-spelling-deprecation. I don't see the request to remove the deprecation (it IS just a warning afterall!) to be particularly motivating until release time (it IS just a warning afterall!), so I'd think it would a better spending of time to implement what Richard suggested.

Right, it takes about the same amount of time, so we may as well implement the simple thing, and argue about something else later if someone sees motivation.


https://github.com/llvm/llvm-project/pull/89807