Re: No bounds checking for dynamic arrays at compile time?

[bearophile]

Walter Bright:

void main() {
    int[5] x;
    x[$] = 1;
    enum size_t n = 2;
    x[$ + n] = 2;
}

The compiler does that already.

I am compiling that little program with

dmd -w test.d

And I see no compilation errors.

See also here, it gives a run-time error:
http://dpaste.dzfl.pl/a62a10aa


void main() {
    int[] x = new int[5];
    x[$] = 1; // easy
    x[x.length] = 1; // idem
    enum size_t n = 2;
    x[$ + n] = 2; // not too much hard if n is unsigned
    x[x.length + n] = 2; // idem
}

I just don't see the point in adding flow analysis for that,

I think that doesn't require flow analysis.


and it'll ding you at runtime anyway.

This thread is about spotting mistakes at compile-time, that is 
one of the main advantages of having a static typing in the first 
place.

Bye,
bearophile