1 files changed, 119 insertions, 0 deletions
diff --git a/test/std/containers/views/span.elem/op_idx.pass.cpp b/test/std/containers/views/span.elem/op_idx.pass.cpp
new file mode 100644
index 0000000000000..a88f4410427a2
--- /dev/null
+++ b/test/std/containers/views/span.elem/op_idx.pass.cpp
@@ -0,0 +1,119 @@
+// -*- C++ -*-
+//===------------------------------ span ---------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===---------------------------------------------------------------------===//
+// UNSUPPORTED: c++98, c++03, c++11, c++14, c++17 
+
+// <span>
+
+// constexpr reference operator[](index_type idx) const;
+// constexpr reference operator()(index_type idx) const;
+//
+
+
+#include <span>
+#include <cassert>
+#include <string>
+
+#include "test_macros.h"
+
+
+template <typename Span>
+constexpr bool testConstexprSpan(Span sp, ptrdiff_t idx)
+{
+    _LIBCPP_ASSERT(noexcept(sp[idx]), "");
+    _LIBCPP_ASSERT(noexcept(sp(idx)), "");
+    
+    typename Span::reference r1 = sp[idx];
+    typename Span::reference r2 = sp(idx);
+    typename Span::reference r3 = *(sp.data() + idx);
+    return r1 == r2 && r2 == r3;
+}
+
+
+template <typename Span>
+void testRuntimeSpan(Span sp, ptrdiff_t idx)
+{
+    _LIBCPP_ASSERT(noexcept(sp[idx]), "");
+    _LIBCPP_ASSERT(noexcept(sp(idx)), "");
+    
+    typename Span::reference r1 = sp[idx];
+    typename Span::reference r2 = sp(idx);
+    typename Span::reference r3 = *(sp.data() + idx);
+    assert(r1 == r2 && r2 == r3);
+}
+
+struct A{};
+constexpr int iArr1[] = { 0,  1,  2,  3,  4,  5,  6,  7,  8,  9};
+          int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
+
+int main ()
+{
+    static_assert(testConstexprSpan(std::span<const int>(iArr1, 1), 0), "");
+
+    static_assert(testConstexprSpan(std::span<const int>(iArr1, 2), 0), "");
+    static_assert(testConstexprSpan(std::span<const int>(iArr1, 2), 1), "");
+
+    static_assert(testConstexprSpan(std::span<const int>(iArr1, 3), 0), "");
+    static_assert(testConstexprSpan(std::span<const int>(iArr1, 3), 1), "");
+    static_assert(testConstexprSpan(std::span<const int>(iArr1, 3), 2), "");
+
+    static_assert(testConstexprSpan(std::span<const int>(iArr1, 4), 0), "");
+    static_assert(testConstexprSpan(std::span<const int>(iArr1, 4), 1), "");
+    static_assert(testConstexprSpan(std::span<const int>(iArr1, 4), 2), "");
+    static_assert(testConstexprSpan(std::span<const int>(iArr1, 4), 3), "");
+
+
+    static_assert(testConstexprSpan(std::span<const int, 1>(iArr1, 1), 0), "");
+
+    static_assert(testConstexprSpan(std::span<const int, 2>(iArr1, 2), 0), "");
+    static_assert(testConstexprSpan(std::span<const int, 2>(iArr1, 2), 1), "");
+
+    static_assert(testConstexprSpan(std::span<const int, 3>(iArr1, 3), 0), "");
+    static_assert(testConstexprSpan(std::span<const int, 3>(iArr1, 3), 1), "");
+    static_assert(testConstexprSpan(std::span<const int, 3>(iArr1, 3), 2), "");
+
+    static_assert(testConstexprSpan(std::span<const int, 4>(iArr1, 4), 0), "");
+    static_assert(testConstexprSpan(std::span<const int, 4>(iArr1, 4), 1), "");
+    static_assert(testConstexprSpan(std::span<const int, 4>(iArr1, 4), 2), "");
+    static_assert(testConstexprSpan(std::span<const int, 4>(iArr1, 4), 3), "");
+
+
+    testRuntimeSpan(std::span<int>(iArr2, 1), 0);
+
+    testRuntimeSpan(std::span<int>(iArr2, 2), 0);
+    testRuntimeSpan(std::span<int>(iArr2, 2), 1);
+
+    testRuntimeSpan(std::span<int>(iArr2, 3), 0);
+    testRuntimeSpan(std::span<int>(iArr2, 3), 1);
+    testRuntimeSpan(std::span<int>(iArr2, 3), 2);
+
+    testRuntimeSpan(std::span<int>(iArr2, 4), 0);
+    testRuntimeSpan(std::span<int>(iArr2, 4), 1);
+    testRuntimeSpan(std::span<int>(iArr2, 4), 2);
+    testRuntimeSpan(std::span<int>(iArr2, 4), 3);
+
+
+    testRuntimeSpan(std::span<int, 1>(iArr2, 1), 0);
+
+    testRuntimeSpan(std::span<int, 2>(iArr2, 2), 0);
+    testRuntimeSpan(std::span<int, 2>(iArr2, 2), 1);
+
+    testRuntimeSpan(std::span<int, 3>(iArr2, 3), 0);
+    testRuntimeSpan(std::span<int, 3>(iArr2, 3), 1);
+    testRuntimeSpan(std::span<int, 3>(iArr2, 3), 2);
+
+    testRuntimeSpan(std::span<int, 4>(iArr2, 4), 0);
+    testRuntimeSpan(std::span<int, 4>(iArr2, 4), 1);
+    testRuntimeSpan(std::span<int, 4>(iArr2, 4), 2);
+    testRuntimeSpan(std::span<int, 4>(iArr2, 4), 3);
+
+    std::string s;
+    testRuntimeSpan(std::span<std::string>   (&s, 1), 0);
+    testRuntimeSpan(std::span<std::string, 1>(&s, 1), 0);
+}