Improve error message when passing in the `storage` keyword as a `type` into a function

[Braqzen]

Reproduce

contract;

storage {
    var: u64,
}

abi MyContract {
    fn test_function(s: storage) -> bool;
}

impl MyContract for Contract {
    fn test_function(s: storage) -> bool {
        let mut s = s;
        s.var = s.var + 1;
        true
    }
}

Error should state something similar to "storage" cannot be used as a type / Cannot pass in "storage" as a type into a function.

Screenshot

cc @FuelLabs/sway-compiler

[mohammadfawaz]

So, we have almost no checks in the compiler against using keywords in places where they don't belong. This is just one example. There are may more such as:

let mut mut = 0;

which compiles without any errors. I think a full solution needs to be implemented in the parser that protects against using keywords where identifiers should go. cc @canndrew, what is the best way to do this?

[mohammadfawaz]

I'm closing this in favour of #1996 which is tracking a general solution for all keywords.