llvm/libcxx/test/std/containers/views/views.span/span.sub/subspan.verify.cpp

//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17

// This test also generates spurious warnings when instantiating std::span
// with a very large extent (like size_t(-2)) -- silence those.
// ADDITIONAL_COMPILE_FLAGS: -Xclang -verify-ignore-unexpected=warning

// <span>

// template<size_t Offset, size_t Count = dynamic_extent>
//   constexpr span<element_type, see-below> subspan() const;
//
// Mandates: Offset <= Extent && (Count == dynamic_extent || Count <= Extent - Offset) is true.

#include <span>
#include <cstddef>

void f() {
  int array[] = {1, 2, 3, 4};
  std::span<const int, 4> sp(array);

  //  Offset too large templatized
  [[maybe_unused]] auto s1 = sp.subspan<5>(); // expected-error@span:* {{span<T, N>::subspan<Offset, Count>(): Offset out of range}}

  //  Count too large templatized
  [[maybe_unused]] auto s2 = sp.subspan<0, 5>(); // expected-error@span:* {{span<T, N>::subspan<Offset, Count>(): Offset + Count out of range}}

  //  Offset + Count too large templatized
  [[maybe_unused]] auto s3 = sp.subspan<2, 3>(); // expected-error@span:* {{span<T, N>::subspan<Offset, Count>(): Offset + Count out of range}}

  //  Offset + Count overflow templatized
  [[maybe_unused]] auto s4 = sp.subspan<3, std::size_t(-2)>(); // expected-error@span:* {{span<T, N>::subspan<Offset, Count>(): Offset + Count out of range}}, expected-error-re@span:* {{array is too large{{(.* elements)}}}}
}