Comment 1 for bug 186155

Here's what I have now:

;;; this one is ok
> (lambda (a [oops 123] b) (values))
Unhandled exception
 Condition components:
   1. &who: lambda
   2. &message: "not an identifier"
   3. &syntax:
       form: (lambda (a (oops 123) b) (values))
       subform: (oops 123)

;;; I don't know what you mean by "could be as good as the 1st". this looks correct to me.
> (define ([oops 123]) (values))
Unhandled exception
 Condition components:
   1. &who: define
   2. &message: "invalid syntax"
   3. &syntax:
       form: (define ((oops 123)) (values))
       subform: #f

;;; this one now lists the whole expression with the subform.
> (define (f [oops 123]) (values))
Unhandled exception
 Condition components:
   1. &who: define
   2. &message: "not an identifier"
   3. &syntax:
       form: (define (f (oops 123)) (values))
       subform: (oops 123)

;;; and so is this one
> (define (f a [oops 123]) (values))
Unhandled exception
 Condition components:
   1. &who: define
   2. &message: "not an identifier"
   3. &syntax:
       form: (define (f a (oops 123)) (values))
       subform: (oops 123)
> ^D