anchor.diff:  	       'hash-key-parser
   	       'in-of-parser
   	       (singleton #'identity (constantly t))
  +	       (keyword-parser 'using)
   	       'hash-value-other-parser))
   
   (define-parser hash-key-no-using-parser
  
positive.code: 			hash-key
  			of
  			hash-table-form
  			using)
  		 (declare (ignore being each hash-key of))
  		 (make-instance 'for-as-hash-value
  		   :var-spec var-spec
  		   :type-spec type-spec
  		   :hash-table-form hash-table-form
  		   :other-var-spec using))
  	       (singleton #'identity (constantly t))
  	       'optional-type-spec-parser
  	       (keyword-parser 'being)
  
negative.code: 			hash-key
  			of
  			hash-table-form
  			using
  			other)
  		 (declare (ignore being each hash-key of using))
  		 (make-instance 'for-as-hash-key
  		   :var-spec var-spec
  		   :type-spec type-spec
  		   :hash-table-form hash-table-form
  		   :other-var-spec other))
  	       (singleton #'identity (constantly t))
  	       'optional-type-spec-parser
  	       (keyword-parser 'being)
  