There is a case that the bytecode does not be outputted.

[Kray-G]

Problem

In the following conditions, the bytecode does not be outputted unfortunately.

• It is const declaration
• It has an initializer which is not constant.
• By a constant folding after analyzing AST, it has been fold to constant such as integer.

Then, the code generator will remove the code because it is a constant and it assumed to be propagated.

Cause

A constant folding is done first before analyzing AST.
After that, analyzing AST will propagate a constant to variables referencing it.
The problem is that a constant folding is done again after analyzing AST.

If the const variable becomes a constant value in the 2nd constant folding phase, the code generator will omit to generate a code even though it has not been propagated.

Code To Reproduce

In the following code, N can be removed because a variable which references it will use directly 3 as a constant. On the other hand, R will be removed but it is a problem because the number 9 has not been correctly propagated yet.

const X = 10;
const Y = X + X;
System.println(Y);

It displays nothing.

Workaround

1. Replace const by var, or
2. Write const Y = 20; directly, or
3. Write it like var YY = X + X; const Y = YY;, if you want Y to be const and to calculate Y by X.