[libcxx-commits] [libcxx] [libc++][spaceship] Implements X::iterator container requirements. (PR #99343)

[Louis Dionne via libcxx-commits]

================
@@ -69,8 +80,11 @@ int main(int, char**) {
 #endif
 
 #if TEST_STD_VER > 17
-  tests<contiguous_iterator<int*> >();
-  static_assert(tests<contiguous_iterator<int*> >(), "");
+  tests<contiguous_iterator<int*>>();
+  static_assert(tests<contiguous_iterator<int*>>());
+
+  tests<three_way_contiguous_iterator<int*>>();
+  static_assert(tests<three_way_contiguous_iterator<int*>>());
----------------
ldionne wrote:

I would declare

```cpp
template <class Iter, bool HasSpaceship = false>
TEST_CONSTEXPR_CXX14 bool tests() {
  ...
  if constexpr (HasSpaceship) {
    ...
  }
}
```

Then:

```cpp
  tests<three_way_contiguous_iterator<int*>, /* has spaceship */ true>();
  static_assert(tests<three_way_contiguous_iterator<int*>, /* has spaceship */ true>());
```

https://github.com/llvm/llvm-project/pull/99343