[Bug c++/53307] internal crash with variadic templates and decltype

[chesstr at hotmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53307

--- Comment #2 from chesstr at hotmail dot com 2012-05-10 20:09:44 UTC ---
Comment on attachment 27366
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=27366
better test case

>#include <iostream>
>template<class...Ts> struct tuple{};
>
>struct funct{
>       template<class T,class...argTs>
>       T operator()(T arg1,argTs...args){
>               return arg1;
>       }
>};
>
>template<class...>class test;
>
>template< template <class...> class tp,
>         class...arg1Ts,
>         class...arg2Ts> 
>class test<tp<arg1Ts...>,tp<arg2Ts...>>{
>public:
>template<class func>
>auto test_pass(func fun,arg2Ts...arg2s) -> decltype(fun(arg2s...)) 
>{
>       int gcc_compiles_this;
>       int internal_gcc_crash=sizeof...(arg2s);
>       return fun(arg2s...);
>}
>template<class func,class...arg3Ts>
>auto testbug(func fun,arg2Ts...arg2s,arg3Ts...arg3s) -> 
>decltype(fun(arg2s...,arg3s...)) 
>{
>       int clang_compiles_but_not_gcc;
>       int internal_gcc_crash=sizeof...(arg2s);
>       return fun(arg2s...,arg3s...);
>}
>};
>
>int main(){    
>       test<tuple<>,tuple<char,int>> t;
>       std::cout<<t.test_pass(funct(),'a',2);
>       std::cout<<t.testbug(funct(),'a',2,100.123);//works fine
>       //std::cout<<t.testbug(funct(),'a',2,"str");//fails 
> <<<<<<<<<<<<<<<<<------------------------
>       std::cout<<"gcc crash : "<<t.testbug(funct(),'a',2);//fails 
> <<<<<<<<<<<<<<<<<<<--------------
>}