func (r region) SliceIndex(n int64) region {
	if r.typ.Kind != KindSlice {
		panic("can't index a non-slice")
	}
	p := r.p.proc.ReadPtr(r.a)
	return region{p: r.p, a: p.Add(n * r.typ.Elem.Size), typ: r.typ.Elem}
}
func (r region) SliceIndex(n int64) region {
	if r.typ.Kind != KindSlice {
		panic("can't index a non-slice")
	}
	p := r.p.proc.ReadPtr(r.a)
	return region{p: r.p, a: p.Add(n * r.typ.Elem.Size), typ: r.typ.Elem}
}
func ( r region ) SliceIndex ( n int64 ) region { if r . typ . Kind != KindSlice { panic ( " " ) } p := r . p . proc . ReadPtr ( r . a ) return region { p : r . p , a : p . Add ( n * r . typ . Elem . Size ) , typ : r . typ . Elem } }
// SliceIndex indexes a slice (a[n]). r must contain a slice.
// n must be in bounds for the slice.
SliceIndex indexes a slice ( a [ n ] ) . r must contain a slice . n must be in bounds for the slice .