char/varchar truncation

I wonder if we actually did the right thing with this.

For example:
select cast('ab' as char(1));

Using sql92's definitions, I read TD as
a fixed length character string and
SD as the same.

Which means I think the section that
comes into play is:

SQL92 6.10 GR5 c ii

ii) If the length in characters of SV is larger than LTD, then
TV is the first LTD characters of SV. If any of the re-
maining characters of SV are non-<space> characters, then a
completion condition is raised: warning-string data, right
truncation.

It looks like SQL99's cast specification is similar for this
case.

Wouldn't that mean the operation is supposed to succeed with
diagnostic information since it's a completion condition not
an exception condition?