[GNATS 26938] MIssing diagnostic for virtual base class which is not an incomplete type

[jhsedg]

Customer bug ID

type_traits/test/is_virtual_base_of_fail.test/is_virtual_base_of_fail.cpp

Description

​[ellen@lin1 status]$ (ia64)(boost)gcc --std=c++20 /tmp/try.C
​In file included from ../boost/type_traits/is_base_of.hpp:12,
​ from ../boost/type_traits/is_virtual_base_of.hpp:12,
​ from ../libs/type_traits/test/compile_fail/is_virtual_base_of_fail.cpp:7:
​../boost/type_traits/is_base_and_derived.hpp: In instantiation of 'const bool boost::detail::is_base_and_derived_impl<UDT, inco
​mplete_type>::value':
​../boost/type_traits/is_base_of.hpp:24:80: required from 'const bool boost::detail::is_base_of_imp<UDT, incomplete_type>::val
​ue'
​../boost/type_traits/is_base_of.hpp:30:48: required from 'struct boost::is_base_of<UDT, incomplete_type>'
​../boost/type_traits/is_virtual_base_of.hpp:57:32: required from 'struct boost::is_virtual_base_of<UDT, incomplete_type>'
​../libs/type_traits/test/compile_fail/is_virtual_base_of_fail.cpp:12:58: required from here
​../boost/type_traits/is_base_and_derived.hpp:226:19: error: invalid use of incomplete type 'struct incomplete_type'
​ 226 | BOOST_STATIC_CONSTANT(bool, value = (BOOST_IS_BASE_OF(B,D) && ! ::boost::is_same<ncvB,ncvD>::value));
​ | ^~~~~~~~~~~~~~~~~
​In file included from ../libs/type_traits/test/compile_fail/is_virtual_base_of_fail.cpp:8:
​../libs/type_traits/test/compile_fail/../test.hpp:416:8: note: forward declaration of 'struct incomplete_type'
​ 416 | struct incomplete_type;
​ | ^~~~~~~~~~~~~~~
​../boost/type_traits/is_virtual_base_of.hpp: In instantiation of 'struct boost::is_virtual_base_of<UDT, incomplete_type>':
​../libs/type_traits/test/compile_fail/is_virtual_base_of_fail.cpp:12:58: required from here
​../boost/type_traits/is_virtual_base_of.hpp:57:32: error: 'value' is not a member of 'boost::is_base_of<UDT, incomplete_type>'
​ 57 | boost::is_base_of<T, U>::value &&
​ | ^~~~~
​../libs/type_traits/test/compile_fail/is_virtual_base_of_fail.cpp: In function 'int main()':
​../libs/type_traits/test/compile_fail/is_virtual_base_of_fail.cpp:12:60: error: 'value' is not a member of 'boost::is_virtual_b
​ase_of<UDT, incomplete_type>'
​ 12 | return boost::is_virtual_base_of<UDT, incomplete_type>::value;
​ | ^~~~~

Notes

​mjh, 2024-01-12:
​
​Reduced test case is (26938a.C):
​
​struct UDT;
​struct incomplete_type;
​bool value(__is_base_of(UDT, incomplete_type));