[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: unassig...@gcc.gnu.org

        ReportedBy: pk...@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;

}