xref: /llvm-project/clang/test/SemaCXX/this-type-deduction-concept.cpp (revision 390b48675be80420f471bd3be74577495b1b1897)
1 // RUN: %clang_cc1 -std=c++23 -verify -fsyntax-only %s
2 // This test case came up in the review of
3 // https://reviews.llvm.org/D159126
4 // when transforming `this` within a
5 // requires expression, we need to make sure
6 // the type of this (and its qualifiers) is respected.
7 
8 // expected-no-diagnostics
9 namespace D159126 {
10 
11 template <class _Tp>
12 concept __member_begin = requires(_Tp __t) {
13   __t.begin();
14 };
15 
16 struct {
17   template <class _Tp>
18   requires __member_begin<_Tp>
operator ()D159126::__anonba17ff2a010819   auto operator()(_Tp &&) {}
20 } inline begin;
21 
22 template <class>
23 concept range = requires {
24   begin;
25 };
26 
27 template <class _Tp>
28 concept __can_compare_begin = requires(_Tp __t) {
29   begin(__t);
30 };
31 
32 struct {
33   template <__can_compare_begin _Tp> void operator()(_Tp &&);
34 } empty;
35 
36 template <range _Rp> struct owning_view {
37   _Rp __r_;
38 public:
emptyD159126::owning_view39   void empty() const requires requires { empty(__r_); };
40 };
41 
42 template <class T>
43 concept HasEmpty = requires(T t) {
44   t.empty();
45 };
46 
47 struct ComparableIters {
48     void begin();
49 };
50 
51 static_assert(HasEmpty<owning_view<ComparableIters&>>);
52 static_assert(HasEmpty<owning_view<ComparableIters&&>>);
53 static_assert(!HasEmpty<owning_view<const ComparableIters&>>);
54 static_assert(!HasEmpty<owning_view<const ComparableIters&&>>);
55 
56 }
57