Intellisense Warnings for C++ 20 ranges

[sean-mcmanus]

Discussed in #8026

^{Originally posted by coulanuk August 21, 2021}
Running the sample code for C++ 20 ranges taken from https://en.cppreference.com/w/cpp/ranges.

VSCode Intellisense warnings appear for :

• no operator "|" matches these operands -- operand types are: std::ranges::filter_view<std::ranges::iota_view<int, int>, type> | std::ranges::views::__adaptor::_RangeAdaptorClosure
• this range-based 'for' statement requires a suitable "begin" function and none was found

The code compiles and runs correctly.
compiler args -std=c++20 are set in tasks.json and c_cpp_properties.json.
See output of C/C++ Log Diagnostics below.
Q: Is there anything else I need to set somewhere to get a clean response from Intellisense?

• OS : Ubuntu 20.04 (Linux x64 5.4.0-81-generic)
• VS Code version : 1.59.0
• Compiler : gcc 10.3.0

-------- Diagnostics - 21/08/2021, 18:27:33
Version: 1.6.0-insiders3
Current Configuration:
{
"name": "Linux",
"includePath": [
"${workspaceFolder}/**"
],
"defines": [],
"compilerPath": "/usr/bin/gcc",
"cStandard": "gnu17",
"cppStandard": "gnu++20",
"intelliSenseMode": "gcc-x64",
"compilerArgs": [
"-std=c++20",
"-g"
],
"browse": {
"limitSymbolsToIncludedHeaders": false
},
"compilerPathIsExplicit": true,
"cStandardIsExplicit": true,
"cppStandardIsExplicit": true,
"intelliSenseModeIsExplicit": true
}
Translation Unit Mappings:
[ /home/coulan/src2/cpp20/testcpp20.cpp ]:
/home/coulan/src2/cpp20/testcpp20.cpp
Translation Unit Configurations:
[ /home/coulan/src2/cpp20/testcpp20.cpp ]:
Process ID: 7926
Memory Usage: 407 MB
Compiler Path: /usr/bin/gcc
Includes:
/usr/include/c++/10
/usr/include/x86_64-linux-gnu/c++/10
/usr/include/c++/10/backward
/usr/lib/gcc/x86_64-linux-gnu/10/include
/usr/local/include
/usr/include/x86_64-linux-gnu
/usr/include
Standard Version: c++20
IntelliSense Mode: linux-gcc-x64
Other Flags:
--g++
--gnu_version=100300
Total Memory Usage: 407 MB

------- Workspace parsing diagnostics -------

[sean-mcmanus]

I've filed an internal bug against our IntelliSense parser. The same also generates 3 other errors from the ranges header itself (which could be the root errors):

"more than one partial specialization matches the template argument list of class "std::__iterator_traits<std::ranges::filter_view<std::ranges::ref_view<const std::initializer_list>, type>::_Iterator, void>" -- "std::__iterator_traits<_Iterator, void>" -- "std::__iterator_traits<_Iterator, void>" -- detected during instantiation of class "std::iterator_traits<_Iterator> [with _Iterator=std::ranges::filter_view<std::ranges::ref_view<const std::initializer_list>, type>::_Iterator]"

"no instance of function template "std::compare_three_way::operator()" matches the argument list -- argument types are: (const std::_V2::error_category *, const std::_V2::error_category *) -- object type is: std::compare_three_way"

"no instance of function template "std::ranges::__cust_iswap::_IterSwap::operator()" matches the argument list -- argument types are: (const std::ranges::iterator_t<std::ranges::ref_view<const std::initializer_list>>, const std::ranges::iterator_t<std::ranges::ref_view<const std::initializer_list>>) -- object type is: const std::ranges::__cust_iswap::_IterSwap -- detected during instantiation of class "std::ranges::filter_view<_Vp, _Pred>::_Iterator [with _Vp=std::ranges::ref_view<const std::initializer_list>, _Pred=type]"

[michelleangela]

This is resolved in https://github.com/microsoft/vscode-cpptools/releases/tag/1.16.0.

[michelleangela]

Fix is now available in release version 1.16.2.