allow inlining of constant constructor variables

[rainbreak]

Currently the constructor does not respect the constant keyword and occupies storage slots unnecessarily.

contract C {
    uint constant x;
    constructor(uint x_) public {
        x = x_;
    }
    function get() public view returns (uint) {
        return x;
    }
}

Here, the function get will sload x from the first storage slot. However x could have instead been inlined into the contract code, avoiding using up any slots and avoiding a relatively expensive sload. This would be important in contracts that use delegatecall and wish to avoid any runtime dependence on their own storage.

[chriseth]

This code does not compile for me and it actually should not occupy any storage slot. Is this intended as a bug report or a feature request?

[chriseth]

This might be a duplicate of #3835

[rainbreak]

Sorry, yes this is a duplicate. Also of #6561