[haberman]

It's not about making compiler implementations easier -- it's about protecting template authors against having someone write:

    class MyBadClass {
      static int bar;
    };
    foo<MyBadClass> y;

By writing "typename", the template author can indicate that "T::bar" the template author can indicate that "bar" is expected to be a type, not a variable. This is explained in more detail here: http://pages.cs.wisc.edu/~driscoll/typename.html.

[pmjordan]

Yes, but my argument is that such an instantiation could easily be determined automatically. The declaration

  T::bar x;

makes no sense under any circumstances if T::bar is not a type. Ergo, putting typename in front is redundant.

[haberman]

Yes but what if your declaration was:

    T::bar * x;

Now the parse is ambiguous. While the language could say "you only need to use typename if the declaration would otherwise be ambiguous," it's simpler and more consistent to say "all qualified dependent types must use typename."