https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113754
Bug ID: 113754
Summary: GCC complains when using a type that depends on lambda
Product: gcc
Version: 13.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: milasudril at gmail dot com
Target Milestone: ---
I tried to use
template<typename T, auto DeleteFn>
using unique_ptr_deleter =
std::unique_ptr<T, decltype([](T* obj) { DeleteFn(obj); })>;
As described by
https://andreasfertig.blog/2022/08/cpp-insights-lambdas-in-unevaluated-contexts/
It works well as long as I do not try define it in a header file. If gcc
detects a from a header file that uses unique_ptr_deleter, I get the warning
lib/array_classes/./memory_block.hpp:12:8: error: 'memory_block' has a field
'unique_ptr_deleter<void, free> terraformer::memory_block::m_pointer' whose
type has internal linkage [-Werror=subobject-linkage]
Clang do generate any warnings.
Stand-alone snippet to reproduce the issue:
#include <memory>
#include <cstdlib>
# 7 "lib/array_classes/./memory_block.hpp"
template<class T, auto DeleteFn>
using unique_ptr_deleter = std::unique_ptr<T, decltype([](T* obj) {
DeleteFn(obj); })>;
class memory_block
{
public:
private:
unique_ptr_deleter<void, free> m_pointer;
};
# 4 "lib/array_classes/memory_block.test.cpp"
