http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54859
Bug #: 54859
Summary: constexpr in template aliase rejected as non-constant
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: leo...@volnitsky.com
clang-3.2 and gcc-4.7.2 compiles, gcc-4.8 rejects:
--------------------------------------------------------------------------
// enbale_if
template <bool B, class T = void>
struct enable_if { typedef T type; };
template <class T>
struct enable_if<false, T> {};
// template alias
template<bool Cnd, class T=void>
using eIF = typename enable_if <Cnd,T>::type;
// f - this compiles
template<bool B=true>
typename enable_if<!B, int>::type f() { return 20; }
// ff - error: integral expression ‘! B’ is not constant
template<bool B=true>
eIF<!B, int> ff() { return 20; }
int main() {}
---------------------------------------------------------------------------
This seams to be related to bug 54648, where I found bad commit to be 191412
