Use of typename keyword with template function parameters

Question

In C++, the typename keyword is needed so the compiler can disambiguate between nested types and nested values in templates. However, there are certain situati

Answer 1

Would be interesting to find what is causing this.

I've been trying to read the standard in search for an answer, please note I'm am novice in this.

However I believe I've found a relevant clause.

§14.6.2. A name used in a template declaration or definition and that is dependent on a template-parameter is assumed not to name a type unless the applicable name lookup finds a type name or the name is qualified by the keyword typename.

I guess this implies that the issue is in the difference of how name lookup works for base specifier lists and function arguments.

Base specifier name lookup:

§10.2. During the lookup for a base class name, non-type names are ignored (3.3.10).

Which explains why typename is not required for base specifiers.

Still looking for function argument name lookup.

Please correct me if this is an incorrect or irrelevant assumption. In the meantime I while keep digging.

The error given by VS2010 when not qualifying the template argument in the function declaration is the following:

'T::type' : dependent name is not a type prefix with 'typename' to indicate a type.

However, I'm still unclear about the rules for dependent function argument name lookup...