hdr.Data = uintptr(unsafe.Pointer(p)) // ERROR "write barrier"
}

func b(hdr *reflect.StringHeader, p *byte) {
	hdr.Data = uintptr(unsafe.Pointer(p)) // ERROR "write barrier"
}

func c(hdrs *[1]reflect.SliceHeader, p *byte) {
	hdrs[0].Data = uintptr(unsafe.Pointer(p)) // ERROR "write barrier"
}

func d(hdr *struct{ s reflect.StringHeader }, p *byte) {
	hdr.s.Data = uintptr(unsafe.Pointer(p)) // ERROR "write barrier"
}

	"unsafe"
)

func main() {
	var (
		buf      = make([]byte, 2<<10)
		large    = string(buf)
		sub      = large[10:12]
		subcopy  = string([]byte(sub))
		subh     = *(*reflect.StringHeader)(unsafe.Pointer(&sub))
		subcopyh = *(*reflect.StringHeader)(unsafe.Pointer(&subcopy))
	)
	if subh.Data == subcopyh.Data {
		panic("sub and subcopy have the same underlying array")
	}

// license that can be found in the LICENSE file.

package main

import (
	"fmt"
	"reflect"
	"unsafe"
)

func main() {
	var s = "abc"
	sh1 := (*reflect.StringHeader)(unsafe.Pointer(&s))
	ptr2 := unsafe.Pointer(unsafe.StringData(s))
	if ptr2 != unsafe.Pointer(sh1.Data) {
		panic(fmt.Errorf("unsafe.StringData ret %p != %p", ptr2, unsafe.Pointer(sh1.Data)))
	}

// (6) Conversion of a reflect.SliceHeader or reflect.StringHeader
// Data field to or from Pointer.

func fromSliceData(s []int) unsafe.Pointer { // ERROR "leaking param: s to result ~r0 level=0$"
	return unsafe.Pointer((*reflect.SliceHeader)(unsafe.Pointer(&s)).Data)
}

func fromStringData(s string) unsafe.Pointer { // ERROR "leaking param: s to result ~r0 level=0$"
	return unsafe.Pointer((*reflect.StringHeader)(unsafe.Pointer(&s)).Data)
}

// and string implementations.
//
// This package allows packages that cannot import "reflect" to use types that
// are tested to be equivalent to reflect.SliceHeader and reflect.StringHeader.
package unsafeheader

import (
	"unsafe"
)

// Slice is the runtime representation of a slice.
// It cannot be used safely or portably and its representation may
// change in a later release.
//

	}
	err = syscall.Mprotect(b, syscall.PROT_NONE)
	if err != nil {
		panic(err)
	}
	// write inaccessible pointers as the data fields of bad1 and bad2.
	(*reflect.StringHeader)(unsafe.Pointer(&bad1)).Data = uintptr(unsafe.Pointer(&b[0]))
	(*reflect.StringHeader)(unsafe.Pointer(&bad2)).Data = uintptr(unsafe.Pointer(&b[1]))

	for _, test := range []struct {
		a, b interface{}
	}{
		{SI{s: bad1, i: 1}, SI{s: bad2, i: 2}},

	switch x := astutil.Unparen(x).(type) {
	case *ast.SelectorExpr:
		// "(6) Conversion of a reflect.SliceHeader or
		// reflect.StringHeader Data field to or from Pointer."
		if x.Sel.Name != "Data" {
			break
		}
		// reflect.SliceHeader and reflect.StringHeader are okay,
		// but only if they are pointing at a real slice or string.
		// It's not okay to do:
		//	var x SliceHeader

//
// (6) Conversion of a [reflect.SliceHeader] or [reflect.StringHeader] Data field to or from Pointer.
//
// As in the previous case, the reflect data structures SliceHeader and StringHeader
// declare the field Data as a uintptr to keep callers from changing the result to
// an arbitrary type without first importing "unsafe". However, this means that
// SliceHeader and StringHeader are only valid when interpreting the content

type immutableBytes []byte

// Bug was failure to leak param b.
func toString(b immutableBytes) string { // ERROR "leaking param: b$"
	var s string
	if len(b) == 0 {
		return s
	}

	strHeader := (*reflect.StringHeader)(unsafe.Pointer(&s))
	strHeader.Data = (*reflect.SliceHeader)(unsafe.Pointer(&b)).Data

	l := len(b)
	strHeader.Len = l
	return s

import (
	"reflect"
	"runtime"
	"unsafe"
)

func k(c chan string, val string) string {
	b := make([]byte, 1000)
	runtime.SetFinalizer(&b[0], func(*byte) {
		c <- val
	})
	var s string
	h := (*reflect.StringHeader)(unsafe.Pointer(&s))
	h.Data = uintptr(unsafe.Pointer(&b[0]))
	h.Len = len(b)
	return s
}

func main() {
	{
		c := make(chan string, 2)
		m := make(map[string]int)
		m[k(c, "first")] = 0