What version of Go are you using (go version)?
go version go1.5.2 darwin/amd64

What did you do?

Ran golang text/scanner Scanner on a file.

GOT:
My program was outputting odd error messages to Stderr.

87:17: illegal char escape

But as text/scanner is a small part of the whole program it wasn't obvious what this message was or where it was coming from. I was reviewing a lot of code until i traced all the back to

https://golang.org/src/text/scanner/scanner.go?s=14356:14385#L531

   326  func (s *Scanner) error(msg string) {
   327      s.ErrorCount++
   328      if s.Error != nil {
   329          s.Error(s, msg)
   330          return
   331      }
   332      pos := s.Position
   333      if !pos.IsValid() {
   334          pos = s.Pos()
   335      }
   336      fmt.Fprintf(os.Stderr, "%s: %s\n", pos, msg)  // <----HERE
   337  }

(The error it self isn't the problem and was correct, it's just the delivery that is the issue).

WANT:

It would be nice to make error output configurable somehow. For my needs, just having a io.Writer (default to os.Stderr) that i can set to ioutil.Discard is all I need but I'm sure others will have more advanced requirements.

thanks all!

nickg