Log the bug report code into the git repo.

gcc-bug-report/README

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+https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66153
+
+Grid code breaks on GCC4.8, 4.9, 5.0 due to the 
+peekIndex<n> operating on lattice.
+
+It erroneously recurses back into the Lattice<obj> variant, even though
+the lattice container is dropped.
+
+Work around is possible; if the Lattice routine is given a disambiguating 
+name prefix, such as 
+
+latPeekIndex<n> 
+
+GCC5 works. 
+
+However this is ugly and for now I have submitted a bug report to see the reaction and
+speed of fixing. 
+
+The simple testcase in this directory is the submitted bug report that encapsulates the
+problem. The test case works with icpc and with clang++, but fails consistently on g++
+current variants.
+
+Peter

gcc-bug-report/broken.cc

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+#include <vector>
+#include <complex>
+#include <type_traits>
+#include <iostream>
+
+typedef std::complex<double> ComplexD;
+
+template <class T> class TypeMapper {
+public:
+  enum { NestLevel = T::NestLevel };
+};
+
+template<> class TypeMapper<ComplexD> {
+public:
+  enum { NestLevel = 0 };
+};
+
+template<class obj> class Container {
+ public:
+  std::vector<obj> data;
+  Container(int size) : data (size){};
+};
+
+template<class obj> class Recursive {
+public:
+  enum { NestLevel = TypeMapper<obj>::NestLevel + 1};
+  obj internal;
+};
+
+template<int N,class obj,typename std::enable_if<N==obj::NestLevel >::type * = nullptr > auto function(const obj &arg)-> obj
+{
+  std::cout<<"Leaf "<<obj::NestLevel<<std::endl;
+  return arg;
+}
+template<int N,class obj,typename std::enable_if<N!=obj::NestLevel >::type * = nullptr > auto function(const obj &arg)-> obj
+{
+  std::cout<<"Node "<<obj::NestLevel<<std::endl;
+  obj ret;
+  ret.internal=function<N>(arg.internal);
+  return ret;
+}
+
+template<int N,class obj> auto function(const Container<obj> & arg)-> Container<decltype(function<N>(arg.data[0]))>
+{
+  Container<decltype(function<N>(arg.data[0]))> ret(arg.data.size());
+  for(int ss=0;ss<arg.data.size();ss++){
+    ret.data[ss] = function<N>(arg.data[ss]);
+  }
+  return ret;
+}
+
+
+int main(int argc,char **argv)
+{
+  Container<Recursive<Recursive<ComplexD> > > array(10);
+  Container<Recursive<Recursive<ComplexD> > > ret(10);
+  
+  ret = function<1>(array);
+}