XO1001: std/sys/<os> used outside the matching target arm

error · reported by the reserved

Platform specific APIs live in std/sys/<os> and may be referenced only inside the arm of a match target.os for that OS, so code for one platform cannot leak into another’s build while every arm is still type checked on every host. The prototype does not emit this code yet: no std/sys/<os> modules exist, and the example below names a hypothetical std/sys/linux function. See core 12.2.

Example

use std/sys/linux

pub fn page_size() -> Int {
  linux.page_size()
}

Fix

use std/sys/linux

pub fn page_size() -> Int {
  match target.os {
    Linux => linux.page_size()
    Darwin => 16384
    Windows => 4096
    Wasi => 65536
  }
}

Run xo explain XO1001 for this text in a terminal, or see section 10.6 of the specification.

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XO1001: std/sys/<os> used outside the matching target arm

Example

Fix