Why do I need a semicolon here?

Here is a test Go program:

package main
import fmt "fmt"
func main () {
    ex := "moo cow\n";
    fmt.Print (ex)
}

With the semicolon, it compiles. However, if the semicolon is removed, it doesn't:

string.go:5: syntax error near fmt

Any ideas?

Update (March 2012): Newer Go releases are able to compile both forms (with and without the semicolon).