go/parser: add clear error on missing , at end of line in composite literal

[rsc]

$ cat x.go
package main

var x = []int{
    1
}
$ gofmt x.go
x.go:4:3: expected '}', found newline
x.go:5:1: expected declaration, found '}'
$ 

Since this is such a common beginning Go programmer mistake,
go/parser should diagnose it directly, saying something like:

x.go:4:3: missing ',' before newline in composite literal

[griesemer]

Comment 1:

See: http://golang.org/cl/5660046
For:
package p
var _ = []int{
    1
}
func _() {
    f(
        1
    )
}
The error message are now:
gofmt x.go
x.go:4:3: missing ',' before newline in composite literal
x.go:9:4: missing ',' before newline in argument list

[griesemer]

Comment 2:

This issue was closed by revision e3f11b3.

Status changed to Fixed.