Can the compiler not determine whether a variable is const by Itself?

Question

I know for a function this simple it will be inlined:

int foo(int a, int b){
    return a + b;
}

But my question is, can't the compiler just auto-detect that this is the same as:

int foo(const int a, const int b){
    return a + b;
}

And since that could be detected, why would I need to type const anywhere? I know that the inline keyword has become obsolete because of compiler advances. Isn't it time that const do the same?

Answer 1

You don't put const as the result of not modifying a variable. You use const to enforce you not modifying it. Without const, you are allowed to modify the value. With const, the compiler will complain.

It's a matter of semantics. If the value should not be mutable, then use const, and the compiler will enforce that intention.