ValueSource valueSource = preptimeValue.value();
if (valueSource == null)
throw new AkibanInternalException("required constant expression: " + expr);
if (node instanceof ConditionExpression) {
Boolean value = valueSource.isNull() ? null : valueSource.getBoolean();
return new BooleanConstantExpression(value);
}
else {
return new ConstantExpression(preptimeValue);
}
}