[Bug c++/102470] New: C++20 NTTP causes ICE

[Bug c++/102470] New: C++20 NTTP causes ICE

[iDingDong at outlook dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102470

            Bug ID: 102470
           Summary: C++20 NTTP causes ICE
           Product: gcc
           Version: 11.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: iDingDong at outlook dot com
  Target Milestone: ---

GCC 11.2 reports ICE to the following piece of code:

//---
#include <concepts>

template <typename T> struct A {
        A(A<T> const&) = default;
};

template <std::same_as<int> T> struct A<T> {
        A(A<T> const&) = default;
};
//---

Compiled with:

> gcc -std=c++20 test.cpp

The error message:

> gcc -std=c++20 test.cpp
> test.cpp: In substitution of 'template<MemAttr attr> using AlignedStorage = std::aligned_storage_t<((const MemAttr)attr).size, ((const MemAttr)attr).align> [with MemAttr attr = memAttrOf<T>]':
> test.cpp:13:75:   required from here
> test.cpp:11:73: internal compiler error: Segmentation fault
>    11 | template <MemAttr attr> using AlignedStorage = ::std::aligned_storage_t<attr.size, attr.align>;
>       |                                                                         ^~~~
> libbacktrace could not find executable to open
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See <https://gcc.gnu.org/bugs/> for instructions.

[Bug c++/102470] C++20 NTTP causes ICE

[iDingDong at outlook dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102470

--- Comment #1 from Kun Ge <iDingDong at outlook dot com> ---
I misplaced the wrong piece of codes.

the code that actually triggered the error is:

//---
#include <cstdlib>
#include <memory>

struct MemAttr {
        std::size_t size;
        std::size_t align;
};

template <typename T> constexpr MemAttr memAttrOf = MemAttr { .size =
sizeof(T), .align = alignof(T) };

template <MemAttr attr> using AlignedStorage =
::std::aligned_storage_t<attr.size, attr.align>;

template <typename T> using AlignedStorageFor = AlignedStorage<memAttrOf<T>>;
//---

[Bug c++/102470] C++20 NTTP causes ICE

[arthur.j.odwyer at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102470

Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |arthur.j.odwyer at gmail dot com

--- Comment #2 from Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> ---
Segfaults starting in GCC 9.1 (the first release with class NTTPs) until 12.3,
succeeds fine in GCC 13.1 and later.
Reduced: https://compiler-explorer.com/z/Kea5ar6MM

struct MA { int x; };
template<class> constexpr int mao = 1;
template<int> struct AST {};
template<MA ma> using AS = AST<ma.x>;
template<class> using ASF = AS<mao<int>>;

<source>: In substitution of 'template<MA ma> using AS = AST<((const MA)ma).x>
[with MA ma = mao<int>]':
<source>:5:39:   required from here
<source>:4:32: internal compiler error: Segmentation fault
    4 | template<MA ma> using AS = AST<ma.x>;
      |                                ^~
0x1bbabfe internal_error(char const*, ...)
0x109f844 strip_array_types(tree_node*)
0x8d3f2c cp_type_quals(tree_node const*)
0x88e40f tsubst_template_args(tree_node*, tree_node*, int, tree_node*)
0x87b764 tsubst(tree_node*, tree_node*, int, tree_node*)
[...]

[Bug c++/102470] C++20 NTTP causes ICE

[ppalka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102470

Patrick Palka <ppalka at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |DUPLICATE
                 CC|                            |ppalka at gcc dot gnu.org
             Status|UNCONFIRMED                 |RESOLVED

--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed by r13-4807, so let's call this a dup of PR103346

*** This bug has been marked as a duplicate of bug 103346 ***