Expression expression = values.get(i);
Symbol valuesSymbol = process(expression, context);
// implicit type conversion
Reference column = context.columns().get(i);
final ColumnIdent columnIdent = column.info().ident().columnIdent();
try {
valuesSymbol = context.normalizeInputForReference(valuesSymbol, column, true);
} catch (IllegalArgumentException | UnsupportedOperationException e) {
throw new ColumnValidationException(column.info().ident().columnIdent().fqn(), e);
}