The best bit is that the type name resolution depends on the current scope, but the scope itself is very unintuitive on edge cases. Jourdan and Pottier in their paper A Simple, Possibly Correct LR Parser for C11 [1] describe several edge cases, including the following case where scope is not necessarily consecutive:
typedef long T, U;
// T is an argument T is a typedef
// vvvvvvvvvvvvvvvvvvvvvvvvvvv ~~~
enum {V} (*f(T T, enum {U} y, int x[T+U]))(T t) {
// T is an argument (until the end of function)
// vvvvvvvvvvvvvvvvvvvvvv
long l = T+U+V+x[0]+y;
return 0;
}
