Array index can be omitted in cases where it's actually needed

[flukiluke]

This should generate an error about no array index, yet is accepted:

Dim b(4)
b() = 100

The runtime behaviour is as-if the index were 0 - which is clearly a side-effect rather than a desired behaviour.

[aouwt]

I would like to mention a bug i found a while ago but forgot to make a report, and i think its relevant here:

When you do Array1() = Array2(), it throws no errors and you are led to think that it sets Array1() to the contents of Array2(), but this is not the case.

[FellippeHeitor]

Rabbit hole goes way deeper.