[libcxx-commits] [libcxx] [libc++] P2255R2: Add deleted tuple constructor overloads (PR #205379)

[A. Jiang via libcxx-commits]

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@@ -689,58 +721,129 @@ public:
                      _Not<is_convertible<_OtherTuple, _Tp> >...,
                      _Not<is_constructible<_Tp, _OtherTuple> >... > > > {};
 
-  template <class... _Up, __enable_if_t< _And< _EnableCtorFromUTypesTuple<const tuple<_Up...>&> >::value, int> = 0>
+  template <bool, class _OtherTuple>
+  struct _EnableCtorFromUTypesTupleNoDangling : false_type {};
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frederick-vs-ja wrote:

I _think_ it would slightly improve compiler throughput if we refactor these into `constexpr` variable templates.

https://github.com/llvm/llvm-project/pull/205379