xref: /llvm-project/libcxx/test/std/containers/views/views.span/span.sub/subspan.verify.cpp (revision 2e9058ced9f154b972e0caac99bc20f284161250)
1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 // UNSUPPORTED: c++03, c++11, c++14, c++17
9 
10 // This test also generates spurious warnings when instantiating std::span
11 // with a very large extent (like size_t(-2)) -- silence those.
12 // ADDITIONAL_COMPILE_FLAGS: -Xclang -verify-ignore-unexpected=warning
13 
14 // <span>
15 
16 // template<size_t Offset, size_t Count = dynamic_extent>
17 //   constexpr span<element_type, see-below> subspan() const;
18 //
19 // Mandates: Offset <= Extent && (Count == dynamic_extent || Count <= Extent - Offset) is true.
20 
21 #include <span>
22 #include <cstddef>
23 
f()24 void f() {
25   int array[] = {1, 2, 3, 4};
26   std::span<const int, 4> sp(array);
27 
28   //  Offset too large templatized
29   [[maybe_unused]] auto s1 = sp.subspan<5>(); // expected-error@span:* {{span<T, N>::subspan<Offset, Count>(): Offset out of range}}
30 
31   //  Count too large templatized
32   [[maybe_unused]] auto s2 = sp.subspan<0, 5>(); // expected-error@span:* {{span<T, N>::subspan<Offset, Count>(): Offset + Count out of range}}
33 
34   //  Offset + Count too large templatized
35   [[maybe_unused]] auto s3 = sp.subspan<2, 3>(); // expected-error@span:* {{span<T, N>::subspan<Offset, Count>(): Offset + Count out of range}}
36 
37   //  Offset + Count overflow templatized
38   [[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)}}}}
39 }
40