File: constexpr-dynamic16.C

package info (click to toggle)
gcc-arm-none-eabi 15%3A14.2.rel1-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid, trixie
  • size: 1,099,328 kB
  • sloc: cpp: 3,627,108; ansic: 2,571,498; ada: 834,230; f90: 235,082; makefile: 79,231; asm: 74,984; xml: 51,692; exp: 39,736; sh: 33,298; objc: 15,629; python: 15,069; fortran: 14,429; pascal: 7,003; awk: 5,070; perl: 3,106; ml: 285; lisp: 253; lex: 204; haskell: 135
file content (20 lines) | stat: -rw-r--r-- 704 bytes parent folder | download | duplicates (2) 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
 
// PR c++/88337 - Implement P1327R1: Allow dynamic_cast/typeid in constexpr.
// { dg-do compile { target c++20 } }
// Here the hint turns out to be wrong: A is a public base of B2, but the
// dynamic_cast operand is not that subobject, but rather a sibling base of
// B2.

struct A { virtual void f(); };
struct B1: A { };
struct B2: A { };
struct C: B1, B2 { };

constexpr C c;
constexpr A *ap = (B1*)&c;
constexpr A &ar = (B1&)c;
constexpr auto p = dynamic_cast<B2*>(ap);
static_assert (p != nullptr);
constexpr auto p2 = dynamic_cast<B2&>(ar);
static_assert(dynamic_cast<B2*>(ap) == (B2*)&c);
static_assert(dynamic_cast<B2*>((B1*)&c) == (B2*)&c);
static_assert(&dynamic_cast<B2&>((B1&)c) == &(B2&)c);