The following built-in functions are not permitted in statement context:
</p>

<pre>
append cap complex imag len make max min new real
unsafe.Add unsafe.Alignof unsafe.Offsetof unsafe.Sizeof unsafe.Slice unsafe.SliceData unsafe.String unsafe.StringData
</pre>

<pre>
h(x+y)
f.Close()
&lt;-ch
(&lt;-ch)
len("foo")  // illegal if len is the built-in function
</pre>

		}

		if input != nil && clone == nil {
			t.Errorf("Clone(%#v) return value should not be equal to nil slice.", input)
		}

		if cap(input) != 0 && unsafe.SliceData(input) == unsafe.SliceData(clone) {
			t.Errorf("Clone(%q) return value should not reference inputs backing memory.", input)
		}
	}

	n := 0
	for i := range length {
		n += len(ss[i])
	}
	b := make([]byte, 0, n)
	for i := range length {
		b = append(b, ss[i]...)
	}
	return unsafe.String(unsafe.SliceData(b), n)
}

// pathJoin - like path.Join() but retains trailing SlashSeparator of the last element
func pathJoin(elem ...string) string {
	sb := bytebufferpool.Get()
	defer func() {
		sb.Reset()