Warning on template parameter identifier shadowing?

[Steven Schveighoffer]

On 8/5/20 12:10 PM, Paul Backus wrote:
> On Wednesday, 5 August 2020 at 11:12:53 UTC, Johan wrote:
>> What do you think about adding a warning about shadowing of an outer 
>> template parameter by an inner template parameter name?
>>
> 
> Not a fan. There are cases where I've done this intentionally--not with 
> eponymous template members, but with private helper templates:
> 
> template foo(T) {
>      enum helper(T) = ...; // error?
>      void foo(T i) {
>          static if (helper!T) ...;
>          else ...;
>      }
> }

I've intentionally done that, and even though it worked, rewrote the 
template parameter names because it's confusing to read.

It would have to be a long deprecation cycle.

I would be in favor of the change.

-Steve