STREAM-ERROR-POSITION-INFO fails on non-string and closed streams

[Jan Moringen]

What I did:
(handler-case
    (with-input-from-string (stream "no-such-package::symbol")
      (read stream))
  (reader-error (condition) (princ-to-string condition)))

What happens:
PRINC-TO-STRING signals an error because STREAM is closed and STREAM-ERROR-POSITION-INFO does not expect that.

What I expected to happen:
PRINC-TO-STRING should produce a string representation of CONDITION (not including position information) without signaling an error.

[Jan Moringen (scymtym)]

Updated patch: STREAM-ELEMENT-TYPE can signal an error for closed streams.