error from hashq-cons-get-handle

[Kevin Ryde]

In guile 1.6.3 built on a recent i386 debian, I noticed
hashq-cons-get-handle seems to call hashx-get-handle with too many
arguments.  For instance,

        (use-modules (ice-9 hcons))
        (define t (make-hash-table 123))
        (hashq-cons-set! t '(x . y) 123)
        (display (hashq-cons-get-handle t '(x . y)))

gives

        ERROR: Wrong number of arguments to hashx-get-handle

where I hoped it might print something like "((x . y) . 123)".