boost::parser compilation error on mac with boost 1.88

[SilkeSchomann]

view_adaptor.hpp (boost::parser) does not compile on a mac with clang 18.1.8 and boost 1.88:

/include/boost/parser/detail/stl_interfaces/view_adaptor.hpp:199:35: error: no template named 'range_adaptor_closure' in namespace 'std::ranges'; did you mean 'std::__range_adaptor_closure'?
199 |     using range_adaptor_closure = std::ranges::range_adaptor_closure<D>;
    |                                                          ^~~~~~~~~~~~~
/bin/../include/c++/v1/__ranges/range_adaptor.h:58:8: note: 'std::__range_adaptor_closure' declared here
58 | struct __range_adaptor_closure {
   |            ^
1 error generated.

[mclow]

Can you try this with the Boost 1.89 release candidate, please?

https://archives.boost.io/release/1.89.0/source/

[SilkeSchomann]

@mclow With the Boost 1.89 release candidate, I am getting exactly the same error message as with version 1.88.

[jwwalker]

What version of the C++ standard are you using? As far as I can tell with cppreference.com, range_adaptor_closure is a C++23 feature.

[SilkeSchomann]

We are using C++ 20 at the moment.

[jwwalker]

The line where you got a compile error is subject to #if BOOST_PARSER_USE_CPP23_STD_RANGE_ADAPTOR_CLOSURE. Earlier in the same file, that macro is defined as follows:

#if BOOST_PARSER_USE_CONCEPTS && defined(__cpp_lib_ranges) &&                  \
    202202L <= __cpp_lib_ranges
#define BOOST_PARSER_USE_CPP23_STD_RANGE_ADAPTOR_CLOSURE 1
#else
#define BOOST_PARSER_USE_CPP23_STD_RANGE_ADAPTOR_CLOSURE 0
#endif

What is the value of __cpp_lib_ranges for you? I take it you are not using Xcode and Apple Clang. Maybe there is some mismatch between the compiler dialect and the version of the standard library you are using.

[tzlaine]

There is. Your stdlib is lying to you. Unfortunately, it's pretty hard to fix this without knowing which versions of clang actually have range_adaptor_closure, and which ones do not. I certainly don't know. I guess I need to spend some quality time with Compiler Explorer.

[tzlaine]

I cannot repro this on Godbolt with Clang 18.1 (or Clang 17). https://godbolt.org/z/3jxEfhfhz

If you can give me a Godbolt repro, I can try and work around the affected compiler version(s).

As of now, I have no way to fix this.

[progheal]

Your stdlib is lying to you.

As this comment pointed out, the problem is not the version of clang, rather the version of libc++. IIRC Clang does not come with a pre-coupled libc++ version, one almost always separately install a version of libc++.

I found this issue when I encountered this exact problem when compiling from boost 1.89. I then checked my libc++ version using this method, which returns something like #define _LIBCPP_VERSION 180000, presumably some version 18. I then checked my package manager and found there is an upgrade to libc++ (according to it, it is "version 27c" upgrading to "version 29"), upgraded it, and the problem went away. The same version check now returns #define _LIBCPP_VERSION 210000, presumably some version 21.

TL;DR: try upgrade libc++.