https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64002
Bug ID: 64002
Summary: Braced initialization of unknown bound array of
nondependent type
Product: gcc
Version: 4.9.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: roger.ferrer at bsc dot es
Hi,
during an initialization of an array of unknown bound of
non-dependent type using a braced initializer which contains
type-dependent expressions, g++ does not "postpone" the computation
of the array size at instantiation time and seems to use the number
of elements inside the braced-initializer.
In all cases the code compiles fine.
#include <cassert>
struct A
{
int x, y;
};
template <typename T>
int f1(T t1, T t2)
{
A a[] = { t1, t2 };
return sizeof(a) / sizeof(a[0]);
}
void test1()
{
assert(f1(A(), A()) == 2); // OK
assert(f1(1, 2) == 1); // ERROR: this assert fails at runtime
}
That said, in the context of C++2011 a parameter pack expansion seems to work
correctly.
template <typename ...T>
int f2(T ...n)
{
A a[] = { n... };
return sizeof(a) / sizeof(a[0]);
}
void test2()
{
assert(f2(A(), A()) == 2); // OK
assert(f2(1, 2) == 1); // OK
}
All asserts pass correctly both in clang-3.5 and icc 14.0.2
Kind regards,
