Please answer these questions before submitting your issue. Thanks!

1. What version of Go are you using (go version)?
   go version go1.6 linux/amd64
2. What operating system and processor architecture are you using (go env)?
   linux/amd64
3. What did you do?
   http://play.golang.org/p/_P4s_RvFbr

This program mistakenly defines a function called "color" that returns a "color.Color". The intent was for the return type to refer to the "image/color" package, but of course the name was shadowed by the function itself.

1. What did you expect to see?
   A non-confusing error message perhaps explaining that "color" is a function or perhaps that "color" refers to itself.
2. What did you see instead?

prog.go:9: typechecking loop involving color
    prog.go:9 color.Color
    prog.go:9 <T>
    prog.go:9 color
    prog.go:9 <node DCLFUNC>

While technically correct, this error message reads like an internal failure of the type checker, especially since it's outputting internal compiler node names and gives no details about what lines 2 through 5 mean.

/cc @griesemer