presto-main/src/main/java/io/prestosql/sql/gen/RowExpressionCompiler.java/RowExpressionCompiler/createTempVariableReferenceExpression
class RowExpressionCompiler:    public static VariableReferenceExpression createTempVariableReferenceExpression(Variable variable, Type type)
    {
        return new VariableReferenceExpression(TEMP_PREFIX + variable.getName(), type);
    }