Effect of importing variables in V2 of an upgradeable contract

Support Upgrades
1

I wonder what is the effect of importing const varaibles to an upgradeable contract. Is the storage slot use arrangement/ sequence affected by this?

Given a contract like this:

import {CONST_A} from "./constants.js" 

contract ContractA {
uintA;
uintB;
MappingC;

funcA() {
CONST_A + 1;
}
}

Then in the upgrade to ContractA, we import and use another const, CONST_B

import {CONST_A, CONST_B} from "./constants.js" 

contract ContractAUpgrade {
uintA;
uintB;
MappingC;

funcA() {
CONST_A + 1;
CONST_B + 2;
}
}

I am assuming storage is not affected since consts are not stored but are resolved to their assigned values at compile time.

2

That's correct. Reference: Solidity docs which says "The compiler does not reserve a storage slot for these variables, and every occurrence is replaced by the respective value."