I solved the error that occurred when using the -std=c++20 flag, but I'm not sure if it's the right thing to do. Indirection requires pointer operand ('size_type' (aka 'unsigned long') invalid)clang(typecheck_indirection_requires_pointer)

[SilmaliTech]

example

#include <vector>
#include <iostream>
int main() {
  #define OPERATORS strong::arithmetic, strong::ordered, strong::equality, strong::incrementable, strong::pointer, strong::iostreamable, strong::unique, strong::convertible_to<std::string>, strong::implicitly_convertible_to<std::string>
  
  using aaaaaaaaa = strong::type<double, struct aaaaaaaaa_, OPERATORS>;
  
  std::vector<aaaaaaaaa> bb;
  if (bb.size() == 0) {
      std::cout << "eorrrrrrr" << std::endl;
  }
}

Compile with commands such as g++13 -std=c++20 =Wall -Werror -pthread.
If you change to -std=c++17, the error will not occur....

In the above code, an error such as Indirection requires pointer operand ('size_type' (aka 'unsigned long') invalid)clang(typecheck_indirection_requires_pointer) occurs.

To resolve this error, you need to remove the "*" keyword from pointer.hpp.
Then the error will disappear.

1. line 90
   original decltype(*std::declval<const T&>())
   Modify decltype(std::declval<const T&>())
2. line 100
   original decltype(&(*std::declval<const T&>())) operator->() const { return &operator*();}
   Modify decltype(&(std::declval<const T&>())) operator->() const { return &operator*();}

If you fix it like this, the error itself won't occur, but I'm not sure if it works properly...

[rollbear]

This is very interesting. Thank you for reporting. I will have a look. The CI pipeline builds with, amongst many others, g++13 -std=c++20 -Wall -Wextra -Wconversion -pedantic -Werror without issue, so your case is surprising.

[rollbear]

Wait, you do realize that the type you're trying to make is completely bonkers and doesn't make any sense what so ever? It's a floating point number, but you want to be able to use it as a pointer and to both implicitly and explicitly convert it to std::string. What would you expect of such a type?

What I can do is to try to make the compilers give you better messages that explains why the cannot possibly ever work.

Do note what the docs say:

• strong::convertible_to<Ts...> provides an explicit operator Ts() const for each type Ts, providing the underlying type supports it.
• strong::pointer allows operator* and operator->, and comparisons with nullptr providing the underlying type supports it.

The underlying type double supports none of those.

[SilmaliTech]

Sorry... I'd like to make an excuse that I'm a C++ beginner... I feel like I'm dying of embarrassment...

[rollbear]

No worries. It takes time to learn. I will make the improvements to the compilation error messages to make the next beginner a little less confused.

[rollbear]

And thank you for bringing this deficiency to my attention.

[SilmaliTech]

Thank you. I want to study hard and have good skills!!