for_loop_dup_index

What it does

Checks whether the index symbol in a for loop is already used in a parent for loop.

Why is this bad?

In nested loops, using the same index symbol for several loops can lead to unexpected and incorrect results.

This rules doesn’t have an automatic fix.

Example

for (x in 1:3) {
  for (x in 1:4) {
    print(x + 1)
  }
}

for (x_outer in 1:3) {
  for (x_inner in 1:4) {
    print(x_inner + 1)
  }
}