clang/test/Modules/merge-constrained-friends.cpp

   1 // RUN: rm -rf %t
   2 // RUN: mkdir -p %t
   3 // RUN: split-file %s %t
   4 //
   5 // RUN: %clang_cc1 -std=c++23 %t/A.cppm -emit-module-interface -o %t/A.pcm
   6 // RUN: %clang_cc1 -std=c++23 %t/Use.cpp -fprebuilt-module-path=%t -fsyntax-only -verify
   7
   8 // RUN: %clang_cc1 -std=c++23 %t/A.cppm -emit-reduced-module-interface -o %t/A.pcm
   9 // RUN: %clang_cc1 -std=c++23 %t/Use.cpp -fprebuilt-module-path=%t -fsyntax-only -verify
  10
  11 //--- A.cppm
  12 module;
  13 export module A;
  14
  15 struct B {};
  16
  17 export template<int N> struct A : B {
  18   friend constexpr const int *f(B) requires true {
  19     static constexpr int result = N;
  20     return &result;
  21   }
  22
  23   template<int M>
  24   friend constexpr const int *g(B) requires (M >= 0) && (N >= 0) {
  25     static constexpr int result = M * 10 + N;
  26     return &result;
  27   }
  28 };
  29
  30 export inline A<1> a1;
  31 export inline A<2> a2;
  32 export inline A<3> a3;
  33
  34 static_assert(f(a1) != f(a2) && f(a2) != f(a3));
  35 static_assert(g<1>(a1) != g<1>(a2) && g<1>(a2) != g<1>(a3));
  36
  37 static_assert(*f(a1) == 1);
  38 static_assert(*f(a2) == 2);
  39 static_assert(*f(a3) == 3);
  40
  41 static_assert(*g<4>(a1) == 41);
  42 static_assert(*g<5>(a2) == 52);
  43 static_assert(*g<6>(a3) == 63);
  44
  45 //--- Use.cpp
  46 // expected-no-diagnostics
  47 import A;
  48
  49 // Try some instantiations we tried before and some we didn't.
  50 static_assert(f(a1) != f(a2) && f(a2) != f(a3));
  51 static_assert(g<1>(a1) != g<1>(a2) && g<1>(a2) != g<1>(a3));
  52 static_assert(g<2>(a1) != g<2>(a2) && g<2>(a2) != g<2>(a3));
  53
  54 A<4> a4;
  55 static_assert(f(a1) != f(a4) && f(a2) != f(a4) && f(a3) != f(a4));
  56 static_assert(g<3>(a1) != g<3>(a4));
  57
  58 static_assert(*f(a1) == 1);
  59 static_assert(*f(a2) == 2);
  60 static_assert(*f(a3) == 3);
  61 static_assert(*f(a4) == 4);
  62
  63 static_assert(*g<4>(a1) == 41);
  64 static_assert(*g<5>(a2) == 52);
  65 static_assert(*g<6>(a3) == 63);
  66
  67 static_assert(*g<7>(a1) == 71);
  68 static_assert(*g<8>(a4) == 84);