Add a test to ensure that RawFd is the size we assume it is.

1 files changed, 11 insertions, 0 deletions

diff --git a/library/std/src/os/unix/io/fd/tests.rs b/library/std/src/os/unix/io/fd/tests.rs
new file mode 100644
index 00000000000..84d2a7a1a91
--- /dev/null
+++ b/library/std/src/os/unix/io/fd/tests.rs
@@ -0,0 +1,11 @@
+use crate::mem::size_of;
+use crate::os::unix::io::RawFd;
+
+#[test]
+fn test_raw_fd_layout() {
+    // `OwnedFd` and `BorrowedFd` use `rustc_layout_scalar_valid_range_start`
+    // and `rustc_layout_scalar_valid_range_end`, with values that depend on
+    // the bit width of `RawFd`. If this ever changes, those values will need
+    // to be updated.
+    assert_eq!(size_of::<RawFd>(), 4);
+}