1// errorcheck -0 -m -l
2
3// Copyright 2017 The Go Authors. All rights reserved.
4// Use of this source code is governed by a BSD-style
5// license that can be found in the LICENSE file.
6
7package foo
8
9// Escape analysis needs to treat the uintptr-typed reflect.*Header fields as pointers.
10
11import (
12	"reflect"
13	"unsafe"
14)
15
16type immutableBytes []byte
17
18// Bug was failure to leak param b.
19func toString(b immutableBytes) string { // ERROR "leaking param: b$"
20	var s string
21	if len(b) == 0 {
22		return s
23	}
24
25	strHeader := (*reflect.StringHeader)(unsafe.Pointer(&s))
26	strHeader.Data = (*reflect.SliceHeader)(unsafe.Pointer(&b)).Data
27
28	l := len(b)
29	strHeader.Len = l
30	return s
31}
32