[libc++] Fix PR35491 - std::array of zero-size doesn't work with non-default constructible types.
Summary:
This patch fixes llvm.org/PR35491 and LWG2157 (https://cplusplus.github.io/LWG/issue2157)
The fix attempts to maintain ABI compatibility by replacing the array with a instance of `aligned_storage`.
Reviewers: mclow.lists, EricWF
Reviewed By: EricWF
Subscribers: lichray, cfe-commits
Differential Revision: https://reviews.llvm.org/D41223
llvm-svn: 324526
diff --git a/libcxx/test/std/containers/sequences/array/indexing.pass.cpp b/libcxx/test/std/containers/sequences/array/indexing.pass.cpp
index 43c4947..7718b92 100644
--- a/libcxx/test/std/containers/sequences/array/indexing.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/indexing.pass.cpp
@@ -56,7 +56,34 @@
C::const_reference r2 = c[2];
assert(r2 == 3.5);
}
-
+ { // Test operator[] "works" on zero sized arrays
+ typedef double T;
+ typedef std::array<T, 0> C;
+ C c = {};
+ C const& cc = c;
+ static_assert((std::is_same<decltype(c[0]), T &>::value), "");
+ static_assert((std::is_same<decltype(cc[0]), const T &>::value), "");
+ if (c.size() > (0)) { // always false
+ C::reference r1 = c[0];
+ C::const_reference r2 = cc[0];
+ ((void)r1);
+ ((void)r2);
+ }
+ }
+ { // Test operator[] "works" on zero sized arrays
+ typedef double T;
+ typedef std::array<const T, 0> C;
+ C c = {{}};
+ C const& cc = c;
+ static_assert((std::is_same<decltype(c[0]), const T &>::value), "");
+ static_assert((std::is_same<decltype(cc[0]), const T &>::value), "");
+ if (c.size() > (0)) { // always false
+ C::reference r1 = c[0];
+ C::const_reference r2 = cc[0];
+ ((void)r1);
+ ((void)r2);
+ }
+ }
#if TEST_STD_VER > 11
{
typedef double T;