https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100956
Bug ID: 100956
Summary: Unused variable warnings ignore "if constexpr" blocks
where variables are conditionally used
Product: gcc
Version: 9.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: mattreecebentley at gmail dot com
Target Milestone: ---
For example, as part of a container class:
void remove_memory_blocks(pointer back_element_in_final_block)
{
if constexpr(!std::is_trivially_destructible<element_type>::value)
{
// destroy each element in each memory block until the back_element is
reached
}
// remove memory blocks
}
If element_type is_trivially_destructible, G++ will warn that
back_element_in_final_block is unused every time the function is called.
Ideally this warning should be performed before constexpr blocks are removed by
a parser (I have no idea what the procedure is for GCC, I'm just guessing here)
