c# - What is the special case with the foreach loop that eliminates bounds checking?

Question

What is the special case with the foreach/for loop that eliminates bounds checking? Also which bounds checking is it?

Answer 1

The standard

for(int i = 0; i < array.Length; i++) {
    ...
}

loop is the one that allows the JIT to safely remove array bounds checks (whether the index is within [0..length-1])

The foreach loop over arrays is equivalent to that standard for loop over arrays.

EDIT: As Robert Jeppesen points out:

This will be optimized if the array is local. If the array is accessible from other locations, bounds checking will still be performed. Reference: Array Bounds Check Elimination in the CLR

Thanks! Didn't know that myself.