clang/test/Modules/GH60336.cpp

   1 // RUN: rm -rf %t
   2 // RUN: %clang_cc1 -x c++ -std=c++20 %s -verify -fmodules -fmodules-cache-path=%t
   3 #pragma clang module build std
   4 module std   [system] {
   5   module concepts     [system] {
   6       module assignable         [system] {
   7     }
   8     export *
   9   }
  10   module functional     [system] {
  11     export *
  12   }
  13
  14
  15   module type_traits     [system] {
  16     export *
  17   }
  18 }
  19
  20 #pragma clang module contents
  21 #pragma clang module begin std.type_traits
  22 namespace std {
  23 template<class _Tp, class _Up>
  24 concept same_as = __is_same(_Tp, _Up);
  25
  26 template <class...>
  27 struct common_reference;
  28
  29 template <class _Tp, class _Up> struct common_reference<_Tp, _Up>
  30 {
  31     using type = _Tp;
  32 };
  33 }
  34 #pragma clang module end // type_traits
  35
  36 #pragma clang module begin std.concepts.assignable
  37 #pragma clang module import std.type_traits
  38 namespace std {
  39 template<class _Tp, class _Up>
  40 concept common_reference_with =
  41   same_as<typename common_reference<_Tp, _Up>::type, typename common_reference<_Up, _Tp>::type>;
  42 }
  43 namespace std {
  44 template<class _Lhs, class _Rhs>
  45 concept assignable_from =
  46   common_reference_with<const __remove_reference_t(_Lhs)&, const __remove_reference_t(_Rhs)&> ;
  47 }
  48 #pragma clang module end // std.concepts.assignable
  49
  50 #pragma clang module begin std.functional
  51 #pragma clang module import std.concepts.assignable
  52 namespace std {
  53 template<class _Sp, class _Ip>
  54 concept sentinel_for = assignable_from<_Ip&, _Ip>;
  55 template <class _Sp, class _Ip>
  56 concept nothrow_sentinel_for = sentinel_for<_Sp, _Ip>;
  57 }
  58 #pragma clang module end   // std::functional
  59 #pragma clang module endbuild // contents
  60
  61
  62 #pragma clang module import std.functional
  63 constexpr bool ntsf_subsumes_sf(std::nothrow_sentinel_for<char*> auto) requires true {
  64   return true;
  65 }
  66 constexpr bool ntsf_subsumes_sf(std::sentinel_for<char*> auto);
  67 static_assert(ntsf_subsumes_sf("foo"));
  68
  69 // Note: Doing diagnostics verify lines in the individual modules isn't
  70 // permitted, and using 'bookmarks' in a module also doesn't work, so we're
  71 // forced to diagnose this by line-number.
  72 //
  73 // Check to ensure that this error happens, prior to a revert of a concepts
  74 // sugaring patch, this diagnostic didn't happen correctly.
  75
  76 // expected-error@* {{partial specialization of 'common_reference<_Tp, _Up>' must be imported from module 'std.type_traits' before it is required}}
  77 // expected-note@63 {{while substituting into concept arguments here}}
  78 // expected-note@*{{partial specialization declared here is not reachable}}