[Bug c++/54763] New: Crash with enable_if (instead of recursive template errors)

[pkeir at outlook dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54763

             Bug #: 54763
           Summary: Crash with enable_if (instead of recursive template
                    errors)
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: pkeir@outlook.com


Created attachment 28308
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28308
C++11 code which causes an internal compiler error

The attached minimised C++11 test case causes an internal compiler error. Clang
instead gives an endless list of errors such as:

fatal error: recursive template instantiation
      exceeded maximum depth of 512

The code, which is also shown below, will run correctly if the enable_if is
instead set to: std::enable_if<(I>0)>::type.

#include <type_traits>

template <unsigned>
struct tint {};

double zod(tint<0>) { return 3.142; }

template <
  unsigned I,
  typename = typename std::enable_if<(I>0),decltype(zod(tint<I-1>()))>::type
>
decltype(zod(tint<I-1>()))
zod(tint<I>) {
  return zod(tint<I-1>());
}

int main(int argc, char *argv[])
{
  zod(tint<0>());
  return 0;
}