evil C++ — template typename vc and GNU compiler

when using 'typedef' to re-define types in template scopes, vc compiler have no restriction in the use of key work 'typename', but gnu did, let's see following examples:

 

template<typename ClassT><br />class TestTemplate<br />{<br /> typedef typename ClassT MyType; // ok on vc compiler<br /> typedef typename ClassT MyType2; // error on GNU compiler, because the type ClassT is not pending</p><p> typedef typename std::vector<ClassT>::iterator IterType; // both go well on vc and gnu<br /> typedef std::vector<ClassT>::iterator IterType; // both error on vc and gnu, because the type vector<> is pending(because ClassT is unknown on first compilation</p><p>};