Iterators over indexing

What it does

It warns if a for loop uses indexing instead of an iterator. If the indexing goes to .len() it will not warn.

Why is this bad?

Accessing a vector by index is slower than using an iterator. Also, if the index is out of bounds, it will panic.

Example

    #[ink(message)]
    pub fn bad_indexing(&self){
        for i in 0..3 {
            foo(self.value[i]);
        }
    }

Use instead:

   #[ink(message)]
   pub fn iterator(&self) {
       for item in self.value.iter() {
            foo(self.value[i]);
       }
   }

// or if its not iterable (with `in`, `iter` or `to_iter()`)

   #[ink(message)]
   pub fn index_to_len(&self){
       for i in 0..self.value.len() {
            foo(self.value[i]);
       }

Implementation

The detector's implementation can be found at this link.