// { dg-do compile } // Contributed by <giovannibajo at gcc dot gnu dot org>, // <pavel_vozenilek at hotmail dot com>, // <bangerth at dealii dot org> // c++/9256: Make sure that a pointer to an array of abstract elements // cannot be created, not even during template substitution (DR337). struct Abstract { virtual void f() = 0; }; // { dg-error "" } struct Complete { void f(); }; /* * TEST 1 * Arrays of abstract elements cannot be declared. */ Abstract a0[2]; // { dg-error "" } Abstract (*a1)[2]; // { dg-error "" } Abstract (**a2)[2]; // { dg-error "" } Abstract (***a3)[2]; // { dg-error "" } Abstract *a4; Abstract *a5[2]; Abstract (*a6[2])[2]; // { dg-error "" } Abstract **a7[2]; Abstract *(*a8[2])[2]; Abstract (**a9[2])[2]; // { dg-error "" } /* * TEST 2 * If a pointer to an array of abstract elements is created during template * instantiation, an error should occur. */ template <class T> struct K { T (*a)[2]; // { dg-error "abstract class type" } }; template struct K<Abstract>; // { dg-error "from here" } /* * TEST 3 * Deducing an array of abstract elements during type deduction is a silent * failure (rejects overload). */ template <bool> struct StaticAssert; template <> struct StaticAssert<true> {}; typedef char Yes; typedef struct { char x[2]; } No; template<typename U> No is_abstract(U (*k)[1]); template<typename U> Yes is_abstract(...); StaticAssert<sizeof(is_abstract<Abstract>(0)) == sizeof(Yes)> b1; StaticAssert<sizeof(is_abstract<Complete>(0)) == sizeof(No)> b2; StaticAssert<sizeof(is_abstract<int>(0)) == sizeof(No)> b3;