to_string_view interferes with FMT_COMPILE formatting

[BillyDonahue]

Similar to #2180 in outcome but I think underlying cause might be different.
https://gcc.godbolt.org/z/rWKEM6

#include <fmt/args.h>
#include <fmt/compile.h>
#include <fmt/format.h>

#include <iostream>
#include <string>
#include <string_view>

struct UserType {
  std::string name;

#ifdef HAS_TO_STRING_VIEW
  friend std::string_view to_string_view(const UserType& ut) { return ut.name; }
#endif
};

template <>
struct fmt::formatter<UserType> : fmt::formatter<std::string_view> {
  using B = fmt::formatter<std::string_view>;
  using B::parse;
  template <typename FC>
  auto format(const UserType& ut, FC& fc) {
    return B::format(std::string_view{ut.name}, fc);
  }
};

void print(const std::string& s) { std::cout << s << std::endl; }

int main() {
  UserType ut{"Alice"};
  print(fmt::format(FMT_COMPILE("[{}]"), ut));
  return 0;
}

Fails only if HAS_TO_STRING_VIEW is defined.
(see godbolt link for full failure output).

In file included from <source>:2:
/opt/compiler-explorer/libs/fmt/trunk/include/fmt/compile.h: In instantiation of 'constexpr OutputIt fmt::v7::detail::field<Char, T, N>::format(OutputIt, const Args& ...) const [with OutputIt = fmt::v7::detail::buffer_appender<char>; Args = {UserType}; Char = char; T = UserType; int N = 0]':
/opt/compiler-explorer/libs/fmt/trunk/include/fmt/compile.h:612:21:   required from 'constexpr OutputIt fmt::v7::detail::concat<L, R>::format(OutputIt, const Args& ...) const [with OutputIt = fmt::v7::detail::buffer_appender<char>; Args = {UserType}; L = fmt::v7::detail::field<char, UserType, 0>; R = fmt::v7::detail::code_unit<char>]'
/opt/compiler-explorer/libs/fmt/trunk/include/fmt/compile.h:613:22:   required from 'constexpr OutputIt fmt::v7::detail::concat<L, R>::format(OutputIt, const Args& ...) const [with OutputIt = fmt::v7::detail::buffer_appender<char>; Args = {UserType}; L = fmt::v7::detail::code_unit<char>; R = fmt::v7::detail::concat<fmt::v7::detail::field<char, UserType, 0>, fmt::v7::detail::code_unit<char> >]'
/opt/compiler-explorer/libs/fmt/trunk/include/fmt/compile.h:827:3:   required from 'std::__cxx11::basic_string<Char> fmt::v7::format(const CompiledFormat&, const Args& ...) [with CompiledFormat = fmt::v7::detail::concat<fmt::v7::detail::code_unit<char>, fmt::v7::detail::concat<fmt::v7::detail::field<char, UserType, 0>, fmt::v7::detail::code_unit<char> > >; Args = {UserType}; Char = char; typename std::enable_if<fmt::v7::detail::is_compiled_format<T>::value, int>::type <anonymous> = 0]'
/opt/compiler-explorer/libs/fmt/trunk/include/fmt/compile.h:877:18:   required from 'std::__cxx11::basic_string<typename Context::char_type> fmt::v7::format(const S&, Args&& ...) [with S = main()::<lambda()>::FMT_COMPILE_STRING; Args = {UserType&}; typename std::enable_if<fmt::v7::detail::is_compiled_string<S>::value, int>::type <anonymous> = 0; typename Context::char_type = char; typename Context::char_type = char]'
<source>:31:44:   required from here
/opt/compiler-explorer/libs/fmt/trunk/include/fmt/compile.h:546:25: error: no matching function for call to 'write<char>(fmt::v7::detail::buffer_appender<char>&, const UserType&)'
  546 |       return write<Char>(out, arg);
      |              ~~~~~~~~~~~^~~~~~~~~~
In file included from /opt/compiler-explorer/libs/fmt/trunk/include/fmt/compile.h:14,
                 from <source>:2:
/opt/compiler-explorer/libs/fmt/trunk/include/fmt/format.h:1789:24: note: candidate: 'template<class OutputIt, class StrChar, class Char> constexpr OutputIt fmt::v7::detail::write(OutputIt, fmt::v7::basic_string_view<Char>, const fmt::v7::basic_format_specs<Char>&)'
 1789 | FMT_CONSTEXPR OutputIt write(OutputIt out, basic_string_view<StrChar> s,
      |                        ^~~~~

[vitaut]

Fixed in 14a2a64. Thanks for reporting.