http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58855
Bug ID: 58855
Summary: Attributes ignored on type alias in template
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: st at quanttec dot com
When compiling the following example the current trunk version of GCC accepts
the attribute in the typedef but not the semantically equivalent type alias.
template <typename T>
void test(T*) {
using T0 = int __attribute__((aligned(1)));
static_assert(alignof(T0) == 1, "wrong alignment"); // no error
typedef T __attribute__((aligned(1))) T1;
static_assert(alignof(T1) == 1, "wrong alignment"); // no error
using T2 = T __attribute__((aligned(1)));
static_assert(alignof(T2) == 1, "wrong alignment"); // error
}
int main() {
test((int*)0);
return 0;
}
> g++ -std=c++11 -Wall -Wextra test.cpp
test.cpp: In function ‘void test(T*)’:
test.cpp:9:42: warning: ignoring attributes applied to dependent type ‘T’
without an associated declaration [-Wattributes]
using T2 = T __attribute__((aligned(1)));
^
test.cpp: In instantiation of ‘void test(T*) [with T = int]’:
test.cpp:14:15: required from here
test.cpp:10:3: error: static assertion failed: wrong alignment
static_assert(alignof(T2) == 1, "wrong alignment"); // error
^
