17.6.3.1? It's in 20.1.1 [lib.equalitycomparable] in C++03 and in 20.2.1 [utility.arg.requirements] in N3225. In C++03, the preceding text states:
In Table 28, T is a type to be supplied by a C + + program instantiating a template, a, b and c are values of type T.
Hmm.. the n3290 seems to place them in 17. I see the wording that establishes the types now.
It makes sense, too; the table describes what it means for T to be EqualityComparable. What would be EqualityComparable if a, b and c were arbitrary?
It should not be defined for arbitrary types. I've never argued that it should -- quite the opposite, in fact. What I've said is that the definition generalizes to a well defined subset of types. I look at the problem like this: if you don't assign types, then the question is, for which set of types of a and b can the expression a == b define an equivalence relation? I know that the behavior is correct for char and int or string and const char*. Why? What's special about those types that make them behave as if I was comparing objects of a single type?