Unread Locals

TIP

This can be configured. Read more about configuration.

This checks function locals that are set by local.set or local.tee but never read with local.get.

(module
  (func
    (local i32)
    i32.const 1
    local.set 0)
  (func (result i32)
    (local i32)
    (local.set 0
      (i32.const 0))
    (local.set 0
      (i32.const 1))
    (local.get 0)))

If there's local.set or local.tee after local.get but no more local.get after that, it will also be considered as unread.

(module
  (func
    (local i32)
    (local.set 0
      (i32.const 1))
    (drop
      (local.get 0))
    (local.set 0
      (i32.const 0))))