DSL EXPRESSION:
$z=0x7fffffffffffffff  + 0x7fffffffffffffff


AST:
"block" [tt:block] [nt:StatementBlock]
    "=" [tt:equals] [nt:Assignment]
        "$z" [tt:field_name] [nt:DirectFieldValue]
        "+" [tt:op_plus] [nt:Operator]
            "0x7fffffffffffffff" [tt:int_literal] [nt:int_literal]
            "0x7fffffffffffffff" [tt:int_literal] [nt:int_literal]

