// PR c++/91364 - Implement P0388R4: Permit conversions to arrays of unknown bound. // { dg-do compile { target c++20 } } struct A { A(); A(const A(&)[2]); }; using T = A[]; using U = A[2]; // t binds directly to U{} now. Before it bound indirectly to a temporary // A{U{}}. ??? But we don't do it now; see reference_binding and the // BRACE_ENCLOSED_INITIALIZER_P block. A (&&t)[] = {U{}}; U u{}; T & foo () { // This didn't compile before P0388R4: invalid initialization of non-const // reference of type 'A (&)[]' from an rvalue of type // ''. return {u}; }