https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62163
Bug ID: 62163
Summary: Dependent function call in constant expression
produces error in template definition context
Product: gcc
Version: 4.9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: hstong at ca dot ibm.com
GCC does not wait until a (dependent) function call is substituted with
arguments before reporting a hard error in the case below.
It appears that GCC tries to evaluate the constant expression with the lookup
results from the template definition context.
### SOURCE (gccSfinaeDependentConstexpr.cc):
unsigned foo(int);
template <unsigned N> struct Q;
template <typename T> void bar(T, Q<foo(T())> * = 0);
void bar(void *) { }
namespace M {
struct Z;
constexpr unsigned foo(Z *) { return 0; }
}
int main() {
M::Z *p = 0;
bar(p);
}
### COMPILER OPTIONS:
-std=c++11
### COMPILER OUTPUT:
gccSfinaeDependentConstexpr.cc:5:44: error: call to non-constexpr function
'unsigned int foo(int)'
template <typename T> void bar(T, Q<foo(T())> * = 0);
^
### COMPILER VERSION INFO:
Using built-in specs.
COLLECT_GCC=/opt/gcc-4.9.0/bin/g++
Target: x86_64-unknown-linux-gnu
Configured with: ./configure --prefix=/home/matthew/gcc-4.9.0-prefix
Thread model: posix
gcc version 4.9.0 (GCC)
