internal compiler error: var without type, init

<pre>1. What is a short input program that triggers the error?
package main

type Type int

func main() {
    switch t := a.(type) {
        case Type:
    }
}

2. What is the full compiler output?
test2.go:6: undefined: a
test2.go:7: internal compiler error: var without type, init: t

3. What version of the compiler are you using?  (Run it with the -V flag.)
6g version 5767+</pre>
