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// P2564R3
// { dg-do compile { target c++20 } }
// { dg-options "-Wno-c++23-extensions" }
consteval int zero (int)
{
return 0;
}
struct A {
// A::A(auto) promoted to consteval.
constexpr A(auto i) { zero (i); }
};
// 'f1<int>' is an immediate function because its body contains a call to an
// immediate constructor 'A<int>' and that call is not a constant expression
constexpr void
f1 (auto i)
{
A a{i};
}
// 'f2<int>' is an immediate function because its body contains a call to an
// immediate constructor 'A<int>' and that call is not a constant expression
constexpr void
f2 (auto i)
{
A a{i};
}
void
f3 (int i)
{
A a{i}; // { dg-error "not a constant expression" }
}
inline void
f7 (int i)
{
A a{i}; // { dg-error "not a constant expression" }
}
constexpr void
f8 (int i)
{
A a{i}; // { dg-error "not a constant expression" }
}
/* "An expression or conversion is immediate-escalating if it is not initially
in an immediate function context" but this one is, so we do *not* promote
f4 to consteval. */
constexpr void
f4 (auto i)
{
if consteval {
A a{i};
}
}
constexpr void
f5 (auto i)
{
if not consteval {
(void) 0;
} else {
A a{i};
}
}
void
f6 (int x)
{
f1 (0);
f1 (x); // { dg-error "not a constant expression" }
f2 (0);
f2 (x); // { dg-error "not a constant expression" }
f3 (0);
f4 (x);
f4 (0);
f5 (x);
f5 (0);
}
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