A generic class constrains its single formal generic parameter to
conform to DOUBLE.  A class which inherits from this class and
provides an actual generic parameter of REAL (which does not conform
to DOUBLE) is accepted without complaint.

Basicly fixed in Prerelease 93.02.17.
Only problem left is that real.conforms_to(double) is false.
Still not fixed in Prerelease 93.04.21.