Currently vectors are the only type represented by a readable datum that are neither self-quoting nor meaningful Scheme expressions (i.e. symbols and lists). I propose switching to making them self-quoting as well.
Currently Racket, Gauche, MIT, Guile, Kawa, Chibi, SCM, STklos, Scheme 9, Scheme 7, UMB, VX, Oaklisp treat vectors as self-quoting; Gambit, Chicken, Bigloo, Scheme48/scsh, SISC, Ikarus, Larceny, Ypsilon, IronScheme, Mosh, KSi, SigScheme, Elk treat unquoted vectors as errors.
Felix Winkelmann points out that signaling an error, rather than is an error, allows relying on the fact that vectors must be quoted to use unquoted vectors for storing meta-information. This is currently done in the alexpander macro expander.
Thus the issue as voted on was misleading - self-quoting is not the only semantics in use. We should consider re-voting on this making it clear that the error option requires an error to be signalled.
For lack of a second, the reopen failed; consequently, the change to make vectors self-quoting stands.
The WG voted to adopt this proposal.