unreachable-code

Flag statements that follow an unconditional return() or stop() in a block — once either runs, nothing after it in the same block can be reached, so the trailing code is dead.

The rule fires only when the terminator is a direct statement of the block (a return()/stop() guarded by an if leaves the tail reachable) and only when the callee resolves to base R; a local redefinition is left alone. return is additionally required to sit inside a function. The deletion fix is unsafe, and withheld when it would drop a comment.

A statement after return() can never run:

f <- function() {
  return(1)
  2
}

warning: unreachable-code
 --> example.R:3:3
  |
3 |   2
  |   ^ code after `return()` can never be reached
  = help: Remove the unreachable code, or fix the control flow.