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