c++ - CRTP with derived class overloading the method -

i encountered problem crtp, can't have same method name (with different signature) in both base , derived class. example reproduce issue following :

template <class t> struct base {     void foo(){}     void bar(){         static_cast<t*>(this)->foo(1,1);     } };  struct derived : public base<derived> {     int foo(int a,int b){ return a+b;} };  int test() {   derived d;   d.bar(); // works   d.foo(1,1); // works   d.foo(); // compilation error } 

i tried under various versions of gcc, clang , icc using godbolt

anybody explain @ work here ?

gcc output:

in function 'int test()': 22 : error: no matching function call 'derived::foo()' d.foo(); // doesn't work ^ 13 : note: candidate: int derived::foo(int, int) int foo(int a,int b){ return a+b;} 

it has nothing crtp, derived::foo shadows base::foo, if had declared foo in inner scope.

one way un-shadow base version, ^[1]place a

using base<derived>::foo; 

in derived.

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^{[1] full example @ (http://coliru.stacked-crooked.com/a/5dc7558e12babbe5).}