https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125971
Bug ID: 125971
Summary: ICE when CTAD occurs before member variable template
partial specialization with dependent type
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Keywords: ice-on-valid-code
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: attackerj1113 at gmail dot com
Target Milestone: ---
The following code causes ICE out on x86-64 gcc since version 11.1(with
-std=c++17 since 8.4) and reproducible on trunk, while Clang/EDG accepted the
code:
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
template<class T>
struct A {
A(T) {}
template<class, class = void>
static constexpr int v = 0;
};
A(int) -> A<int>;
A a(0);// CTAD before specialization
template<class T>
template<class U>
constexpr int A<T>::v<U, typename U::type> = 1;
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
https://godbolt.org/z/vcEbsqWdq
GCC crashes if class template argument deduction (CTAD) is performed before a
member variable template partial specialization involving a dependent type
(typename U::type) is declared. Reordering the specialization before CTAD
avoids the crash.
