https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93248
Bug ID: 93248
Summary: ICE in decltype of template constructor with default
argument within a class template
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: rene.r...@fu-berlin.de
Target Milestone: ---
Hi gcc team,
I stumbled over the following weird scenario causing an ICE with gcc>=8.3 but
seems to be fine for the gcc 7 series.
Here is the code in question:
```
#include <vector>
template <typename t>
struct foo
{
template <typename some_t>
constexpr foo(t const it,
some_t const index,
size_t const my_index = 0) :
m_it{it},
m_index{index},
m_my_index{my_index}
{}
t m_it{};
size_t m_index{};
size_t m_my_index{};
};
int main()
{
using foo_t = decltype(foo{10, 4u, 2}); // works
// using foo_ice_t = decltype(foo{10, 4u}); // ICE: type deduction in
decltype seems to cause this?
using foo_fine_t = decltype(foo<size_t>{10, 4u}); // explicit type
declaration works fine.
foo f{10, 3u}; // works fine out of decltype expression.
}
```
The second decltype expression for foo_ice_t causes an ICE for gcc>=8.1 but not
for gcc7.5. If I use the type deduction to create an object of foo everything
works as expected. Can you help me with this?
Many thanks in advance.
