[format.formatter.spec]/5 lists the requirements for the default
formatter. The original implementation didn't implement this. This
implements the default formatter according to the Standard.
This adds additional test to validate the default formatter is disabled
and the required standard formatters are enabled.
While adding the tests it seems the formatters needed a constraint for the
character types they were valid for.
Implements parts of:
- P0645 Text Formatting
Depends on D115988
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D115989
Right now we drop the char_traits template argument, which presumes that
string<_CharT, _Traits> and string<_CharT> are interchangeable.
Reviewed By: Mordante, #libc, Quuxplusone
Differential Revision: https://reviews.llvm.org/D112017
Implements the formatter for all string types.
[format.formatter.spec]/2.2
For each charT, the string type specializations
```
template<> struct formatter<charT*, charT>;
template<> struct formatter<const charT*, charT>;
template<size_t N> struct formatter<const charT[N], charT>;
template<class traits, class Allocator>
struct formatter<basic_string<charT, traits, Allocator>, charT>;
template<class traits>
struct formatter<basic_string_view<charT, traits>, charT>;
```
This removes the stub implemented in D96664.
Implements parts of:
- P0645 Text Formatting
- P1868 width: clarifying units of width and precision in std::format
Reviewed By: #libc, ldionne, vitaut
Differential Revision: https://reviews.llvm.org/D103425
Mark de Wever