gcc/testsuite/g++.dg/contracts/contracts-constexpr2.C

// ensure that failing pre/post can fail at constexpr time
// { dg-do compile }
// { dg-options "-std=c++20 -fcontracts -fcontract-continuation-mode=on" }

constexpr int ffun(int a)
  [[ pre: a > 0 ]]
  [[ post r: r > 10 ]]
{
  return a;
}

template<typename T>
constexpr int ftfun(T a)
  [[ pre: a > 0 ]]
  [[ post r: r > 10 ]]
{
  return a;
}

constexpr int explicitfn(int a)
  [[ pre ignore: a > 0 ]]
  [[ pre check_maybe_continue: a > 0 ]]
  [[ post ignore r: r > 10 ]]
  [[ post check_maybe_continue r: r > 10 ]]
{
  return a;
}

template<typename T>
constexpr int ftfun2(T a)
  [[ pre: a > 0 ]]
  [[ post r: r > 10 ]]
{
  return a;
}

int main(int, char **) {
  constexpr int a = ffun(-10);
  // { dg-error "contract predicate" "" { target *-*-* } 6 }
  constexpr int b = ftfun(-10);
  // { dg-error "contract predicate" "" { target *-*-* } 14 }
  constexpr int c = explicitfn(-10);
  // { dg-error "contract predicate" "" { target *-*-* } 22 }
  constexpr int d = ftfun2(-10.0);
  // { dg-error "contract predicate" "" { target *-*-* } 31 }

  constexpr int e = ffun(5);
  // { dg-error "contract predicate" "" { target *-*-* } 7 }
  constexpr int f = ftfun(5);
  // { dg-error "contract predicate" "" { target *-*-* } 15 }
  constexpr int g = explicitfn(5);
  // { dg-error "contract predicate" "" { target *-*-* } 24 }
  constexpr int h = ftfun2(5.5);
  // { dg-error "contract predicate" "" { target *-*-* } 32 }

  return 0;
}