Insert

(gv-define-simple-setter aref aset)

in a buffer and try to edebug-eval it (C-u C-M-x).

It gives an error which I don't understand, because the second argument
`aset' should match symbolp...

I also tried this on the build from master and the error is the same.

Debugger entered--Lisp error: (invalid-read-syntax "Expected" (&or symbolp lambda-expr))
  signal(invalid-read-syntax ("Expected" (&or symbolp lambda-expr)))
  edebug-syntax-error("Expected" (&or symbolp lambda-expr))
  apply(edebug-syntax-error ("Expected" (&or symbolp lambda-expr)))
  edebug-no-match(((aset) (176 . 180) . 181) "Expected" (&or symbolp lambda-expr))
  edebug-match-list(((aset) (176 . 180) . 181) (&or symbolp lambda-expr))
  edebug-match-one-spec(((aset) (176 . 180) . 181) (&or symbolp lambda-expr))
  edebug-match-specs(((aset) (176 . 180) . 181) ((&or symbolp lambda-expr) &optional sexp) edebug-match-specs)
  edebug-match-specs(((aset) (176 . 180) . 181) (sexp (&or symbolp lambda-expr) &optional sexp) edebug-match-specs)
  edebug-match-sublist(((aset) (176 . 180) . 181) (sexp (&or symbolp lambda-expr) &optional sexp))
  #f(compiled-function (head cursor) #<bytecode 0x194f427789f7f1ec>)(gv-define-simple-setter ((aset) (176 . 180) . 181))
  edebug-list-form(((aset) (176 . 180) . 181))
  edebug-form((((gv-define-simple-setter aref aset)) (146 (147 . 170) (171 . 175) (176 . 180) . 181)))
  edebug-make-form-wrapper((((gv-define-simple-setter aref aset)) (146 (147 . 170) (171 . 175) (176 . 180) . 181)) 146 181 nil)
  edebug-read-and-maybe-wrap-form1()
  edebug-read-and-maybe-wrap-form()
  edebug--read(read #<buffer *scratch*>)
  apply(edebug--read read #<buffer *scratch*>)

-- 
Best regards,
  Matúš Goljer