Experimenting what would be the best way to store constants in Solidity.

StorageVsFunctionTest.sol

// SPDX-License-Identifier: MIT
pragma solidity 0.8.4;

// A simple contract to test the differences of gas usage between accessing a storage variable and using a return value of a function.
// Result: more than 2000 less gass consumed by getFromInline() and getFromImmutable() than getFromStorage() (if called in a transaction).
// Conclusion: it's better not to use storage variables for constants.
contract StorageVsFunctionTest {
    
    address internal uniAddress = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
    address internal immutable uniAddressImmutable;
    
    constructor() {
        uniAddressImmutable = 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
    }
    
    function getFromImmutable() public view returns (address) {
        return uniAddressImmutable;
    }
    
    function getFromInline() public pure returns (address) {
        return 0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D;
    }
    
    function getFromStorage() public view returns (address) {
        return uniAddress;
    }
}