// just the contents of the pointer being passed, not any other part
// of the memory allocation. This is run after checkIndex, which looks
// for the special case of &a[i], which requires different checks.
func (p *Package) checkAddr(sb, sbCheck *bytes.Buffer, arg ast.Expr, i int) bool {
	// Strip type conversions.
	px := &arg
	for {
		c, ok := (*px).(*ast.CallExpr)