diff --git a/filedescriptor/src/unix.rs b/filedescriptor/src/unix.rs
index 58bdeaaf4..6d48d602a 100644
--- a/filedescriptor/src/unix.rs
+++ b/filedescriptor/src/unix.rs
@@ -321,10 +321,7 @@ impl Pipe {
         let mut fds = [-1i32; 2];
         let res = unsafe { libc::pipe(fds.as_mut_ptr()) };
         if res == -1 {
-            bail!(
-                "failed to create a pipe: {:?}",
-                std::io::Error::last_os_error()
-            )
+            Err(Error::Pipe(std::io::Error::last_os_error()))
         } else {
             let mut read = FileDescriptor {
                 handle: OwnedHandle {
@@ -382,10 +379,7 @@ pub fn socketpair_impl() -> Result<(FileDescriptor, FileDescriptor)> {
     let mut fds = [-1i32; 2];
     let res = unsafe { libc::socketpair(libc::PF_LOCAL, libc::SOCK_STREAM, 0, fds.as_mut_ptr()) };
     if res == -1 {
-        bail!(
-            "failed to create a socketpair: {:?}",
-            std::io::Error::last_os_error()
-        )
+        Err(Error::Socketpair(std::io::Error::last_os_error()))
     } else {
         let mut read = FileDescriptor {
             handle: OwnedHandle {
@@ -443,7 +437,7 @@ mod macos {
         if fd < 0 {
             return Err(Error::IllegalFdValue(fd.into()));
         }
-        if fd >= FD_SETSIZE {
+        if fd as usize >= FD_SETSIZE {
             return Err(Error::FdValueOutsideFdSetSize(fd.into()));
         }
         Ok(())