#embed interacts poorly with template argument deduction and initializer lists

[cor3ntin]

Clang incorrectly rejects the following because it fails to deduce the correct size for the array/initializer list

static constexpr auto std_to_char_array = std::to_array<char>({
         #embed __FILE__
         , '\0'
    });
  static constexpr auto initializer_list = std::initializer_list<char>{
      #embed __FILE__
       , '\0'
  };

https://godbolt.org/z/4oj8Tr4d5

(From reddit)

[cor3ntin]

@Fznamznon

[llvmbot]

@llvm/issue-subscribers-clang-frontend

Author: cor3ntin (cor3ntin)

Clang incorrectly rejects the following because it fails to deduce the correct size for the array/initializer list ```cpp

static constexpr auto std_to_char_array = std::to_array<char>({
#embed FILE
, '\0'
});
static constexpr auto initializer_list = std::initializer_list<char>{
#embed FILE
, '\0'
};

https://godbolt.org/z/4oj8Tr4d5

([From reddit](https://www.reddit.com/r/cpp/comments/1hxdv17/experimenting_with_embed/))
</details>

[llvmbot]

@llvm/issue-subscribers-c-1

Author: cor3ntin (cor3ntin)

Clang incorrectly rejects the following because it fails to deduce the correct size for the array/initializer list ```cpp

static constexpr auto std_to_char_array = std::to_array<char>({
#embed FILE
, '\0'
});
static constexpr auto initializer_list = std::initializer_list<char>{
#embed FILE
, '\0'
};

https://godbolt.org/z/4oj8Tr4d5

([From reddit](https://www.reddit.com/r/cpp/comments/1hxdv17/experimenting_with_embed/))
</details>

[pinskia]

Note I filed a bug for GCC here: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118390 .