Before filing a bug, please check whether it has been fixed since
the latest release: run "hg pull", "hg update default", rebuild, and
retry
what you did to
reproduce the problem.  Thanks.

What steps will reproduce the problem?

package main

import (
    "io"
    "fmt"
    "bufio"
)

type testReader struct {}

func (r *testReader) Read(p []byte) (int, error) {
    return copy(p, "abcd"), io.EOF
}

func main() {
    buf := bufio.NewReaderSize(new(testReader), 32)
    s, err := buf.Peek(2)
    fmt.Println(string(s),err)
}


What is the expected output?
ab <nil>

What do you see instead?
ab EOF

Which compiler are you using (5g, 6g, 8g, gccgo)?
8g

Which operating system are you using?
linux

Which revision are you using?  (hg identify)
e01251826b3a tip

Please provide any additional information below.

The last if clause in the Peek function will always be false.

In the case that an error is returned, should it use
b.err instead or b.readErr()? Otherwise it will eat the 
error and it wont be available for next Read call.