Re: C++17 and "Alice in Wonderland"

From: Edward Diener (eldiener_at_[hidden])
Date: 2021-03-24 13:46:58

On 3/24/2021 12:42 AM, Felipe Magno de Almeida via Boost wrote:
> On Tue, Mar 23, 2021 at 5:13 PM Edward Diener via Boost
> <boost_at_[hidden]> wrote:
> 
> Hello Edward,
> 
>> I apologize for this non-Boost related post, but I ran into what I
>> thought was a C++17 bug in clang ( also in vc++14.2 C++17 ), whose
>> explanation to me of why it is not a bug really sounds like the
>> non-logic of "Alice in Wonderland".
> 
> [snip]
> 
>> My bug
>> report is at https://bugs.llvm.org/show_bug.cgi?id=49684 and the
>> explanation given there just eludes me as to what C++17 is doing,
> 
> [snip]
> 
> Aren't consts ignored in function parameters?

Why are consts ignored in function parameters ? Is not
void f(int const) different from void f(int) ? In one the argument 
passed can not be changed and in the other it can. How can they be the 
same ?

> Then the parameter is not
> const and you have a mismatch. Can't you use different parameter types
> and use SFINAE by comparing the two after removing const?

Thanks ! Maybe I can. But to have to do so in such a simple situation 
seems very strange.