Dereferenced pointer in tablesample.c

Hi all,
(Petr in CC)

Coverity is complaining about the following pointer dereference in
tablesample_init(at)tablesample(dot)c:
+ ExprState *argstate = ExecInitExpr(argexpr, (PlanState *)
scanstate);
+
+ if (argstate == NULL)
+ {
+ fcinfo.argnull[i] = true;
+ fcinfo.arg[i] = (Datum) 0;;
+ }
+
+ fcinfo.arg[i] = ExecEvalExpr(argstate, econtext,
+
&fcinfo.argnull[i], NULL);

If the expression argstate is NULL when calling ExecInitExpr(), argstate is
going to be NULL and dereferenced afterwards, see execQual.c for more
details. Hence I think that the patch attached should be applied. Thoughts?

At the same time I noted a double semicolon, fixed as well in the attached.
Regards,
--
Michael