Templates, varargs and static foreach

[%u]

I would like to do the following:

void foo() {}
void bar(int a) { foo(); } // 1
void bar(int a, int b) { foo(); foo(); } // 2
void bar(int a, int b, int c) { foo(); foo(); foo(); } // 3
void bar(int[] a) { foreach(b; a) foo(); } // 4

The forms 1-3 should be called, when the amount of arguments is known at compile time. Otherwise
4 is called.

Ok - this is a major simplification of the design I'm using. I would like to shorten it using
templates. I have tried this:

void foo() {}
void bar(A...)(A a) { foo(); static if (a.length > 1) { bar(a[1..length]); }
void bar(A)(A[] a) { foreach(t;a) foo(); }

The problem is that the recursion happens on runtime (unless I specify -O -release -inline). Can
the compiler guarantee that the recursion is unfolded, when all those optimizations are on or is
there a static for/foreach for doing this in a better way.