"invalid datums in quotation" should be suppressed

> ((eval (list 'quote (lambda () 'hello!)) (scheme-report-environment 5)))

Warning: invalid datum in quotation
         #{Procedure 8664}
         (&warning)
'hello!
> 

The spirit of the warning is correct, but there should be follow-through in the form of replacing the (quote ...) form with syntax error code, as happens with other static errors e.g.

> (lambda ())

Warning: invalid expression
         (#{Name lambda} ())
         (&syntax-error)
'syntax-error
> 

(Better would be for a run-time error to result, not just a bogus value.)

The reasoning is the same as that for converting mutable to immutable values when they're quoted, and has to do with supporting cross-compilation and capability security applications. The prohibition is allowed by the Scheme reports (due to the specified syntax of the QUOTE special form).

Best
Jonathan