cppcheck won't build with new gcc-13 nor clang++ 16.0.2

[dcb]

Fedora 38 has been released with new gcc-13. Some newish C++ syntax
for lambdas in the source code of cppcheck doesn't compile.

/usr/include/c++/13/bits/alloc_traits.h: In instantiation of ‘struct std::__allocator_traits_base::__rebind<taggedallocator\<referencetoken, 3="">, ReferenceToken, void>’:
/usr/include/c++/13/bits/alloc_traits.h:94:11: required by substitution of ‘template<class _alloc,="" class="" _up=""> using std::__alloc_rebind = typename std::__allocator_traits_base::__rebind<_Alloc, _Up>::type [with _Alloc = TaggedAllocator<referencetoken, 3="">; _Up = ReferenceToken]</referencetoken,>’
/usr/include/c++/13/bits/alloc_traits.h:228:8: required by substitution of ‘template<class _alloc=""> template<class _tp=""> using std::allocator_traits< <template-parameter-1-1> >::rebind_alloc = std::__alloc_rebind<_Alloc, _Tp> [with _Tp = ReferenceToken; _Alloc = TaggedAllocator<referencetoken, 3="">]</referencetoken,>’
/usr/include/c++/13/ext/alloc_traits.h:126:65: required from ‘struct __gnu_cxx::__alloc_traits<taggedallocator\<referencetoken, 3="">, ReferenceToken>::rebind<referencetoken>’
/usr/include/c++/13/bits/stl_vector.h:88:21: required from ‘struct std::_Vector_base<referencetoken, taggedallocator\<referencetoken,="" 3=""> >’
/usr/include/c++/13/bits/stl_vector.h:423:11: required from ‘class std::vector<referencetoken, taggedallocator\<referencetoken,="" 3=""> >’
lib/smallvector.h:47:7: required from ‘class SmallVector<referencetoken>’
lib/astutils.cpp:1158:58: required from here
/usr/include/c++/13/bits/alloc_traits.h:70:31: error: static assertion failed: allocator_traits::rebind_alloc<a::value_type> must be A
70 | _Tp>::value,
| ^~~~~</a::value_type></referencetoken></referencetoken,></referencetoken,></referencetoken></taggedallocator\<referencetoken,></template-parameter-1-1></class></class></class></taggedallocator\<referencetoken,>

I also tried clang++ version 16.0.2 and that didn't like the source code either:

In file included from lib/astutils.cpp:21:

In file included from lib/astutils.h:26:
In file included from /usr/bin/../lib/gcc/x86_64-redhat-linux/13/../../../../include/c++/13/stack:62:
In file included from /usr/bin/../lib/gcc/x86_64-redhat-linux/13/../../../../include/c++/13/deque:65:
In file included from /usr/bin/../lib/gcc/x86_64-redhat-linux/13/../../../../include/c++/13/bits/stl_uninitialized.h:64:
In file included from /usr/bin/../lib/gcc/x86_64-redhat-linux/13/../../../../include/c++/13/ext/alloc_traits.h:34:
/usr/bin/../lib/gcc/x86_64-redhat-linux/13/../../../../include/c++/13/bits/alloc_traits.h:68:2: error: static assertion failed due to requirement 'is_same<std::allocator\<referencetoken>, TaggedAlloc ator\<referencetoken, 3="">>::value': allocator_traits</referencetoken,></std::allocator\<referencetoken>::rebind_alloc<a::value_type> must be A
static_assert(is_same<
^ ~~~~~~~~
/usr/bin/../lib/gcc/x86_64-redhat-linux/13/../../../../include/c++/13/bits/alloc_traits.h:94:5: note: in instantiation of template class 'std::__allocator_traits_base::__rebind<taggedallocator\<refer encetoken,="" 3="">, ReferenceToken>' requested here
using __alloc_rebind
^</taggedallocator\<refer></a::value_type>

I don't really want to drop back to previous versions of cppcheck.

        Both gcc and clang not liking
        the code suggests to me that the cppcheck code is not quite right.

[CHR]

If someone would finish this PR... https://github.com/danmar/cppcheck/pull/5015/

[dcb]

Thanks for the information.

Given that cppcheck has to compile with a variety of C++ compilers, I'd be tempted to rework the cppcheck code into something most C++ compilers can easily accept.

Writing bleeding edge C++ code that some compilers have trouble implementing is IMHO asking for trouble.

[Daniel Marjamäki]

Given that cppcheck has to compile with a variety of C++ compilers, I'd be tempted to rework the cppcheck code into something most C++ compilers can easily accept.

As far as I know that is our approach. Do you see some bleeding edge C++ code?

According to the PR the problem is the opposite.. bleeding edge libraries require some attribute that we don't have?

[dcb]

Do you see some bleeding edge C++ code?

Yes, use of lambdas. They have only been around since C++11 and have been enhanced
ever since (C++14, C++17). That's probably ok if cppcheck only had to work with one compiler.

I'd be interested to find out which C++ compiler accepts the current cppcheck code.
MS maybe ?

[Daniel Marjamäki]

We do require some C++11 features. I do not think there is C++14 or later features. You can compile cppcheck source code with g++ 4.8 so the problem is not that we are too bleeding edge.

[Daniel Marjamäki]

C++11 lambdas is something we do require.

[dcb]

Two workarounds:

1. The static assert went into gcc trunk on 2022-12-14, so use a compiler from before then.
   20221204 seems to work.

2. More brutally, remove the static assert from the alloc_traits.h header file.
   This will affect other builds.

[Daniel Marjamäki]

have you tried to apply the changes in PR 5015?

https://github.com/danmar/cppcheck/pull/5015/files

[dcb]

apply the changes in PR 5015?

Yes and the changes make it work for both gcc and clang. Thanks very much !

Some warnings were produced, I will make those the subject of another thread.