piping tuple into a test case enforces const-ness of passed type instances

[ambushed]

Expected Behavior

I would like to be able to call non-const methods on a tuple member, i.e. the code below should compile:

struct Type1 {
    int get_num_const() const {return 1;}
    int get_num() {return 1;} 
};

int main() {
  using namespace boost::ut;

  "types"_test =
      []<class T>(T& t) {
        expect(that% t.get_num() == 2) << reflection::type_name<T>() << "failed the test"; // "Type1" failed the test.
      } | std::tuple{Type1{}};
}

Actual Behavior

Instead, I am getting a compile error:

<source>:19:31: error: passing 'const Type1' as 'this' argument discards qualifiers [-fpermissive]
   19 |         expect(that% t.get_num() == 2) << reflection::type_name<T>() << "failed the test";
      |                      ~~~~~~~~~^~
<source>:10:9: note:   in call to 'int Type1::get_num()'
   10 |     int get_num() {return 1;}
      |         ^~~~~~~

At the moment, i am forced to hack the const modifier away (e.g.: auto* t1 = const_cast<std::remove_const<T>::type*>(&t))

Looking at the ut internals, the issue can be "fixed" by removing const modifier of the arg parameter in the following line

ut/include/boost/ut.hpp

Line 607 in 20f2c3f

static constexpr auto run_impl(T test, const TArg& arg)

and let the user decide whether the param is being passed as a const reference or a mutable one?

Steps to Reproduce the Problem

1. See the godbolt link

Specifications

• Version: master
• Platform: macOS m1
• Subsystem: clang