diff --git a/crates/host_env/src/select.rs b/crates/host_env/src/select.rs
index 89988ee96af..922bafe0697 100644
--- a/crates/host_env/src/select.rs
+++ b/crates/host_env/src/select.rs
@@ -6,6 +6,7 @@ pub mod platform {
     pub use libc::{FD_ISSET, FD_SET, FD_SETSIZE, FD_ZERO, fd_set, select, timeval};
     pub use std::os::unix::io::RawFd;
 
+    #[must_use]
     pub const fn check_err(x: i32) -> bool {
         x < 0
     }
@@ -52,6 +53,7 @@ pub mod platform {
         unsafe { __WSAFDIsSet(fd as _, set) != 0 }
     }
 
+    #[must_use]
     pub fn check_err(x: i32) -> bool {
         x == WinSock::SOCKET_ERROR
     }