diff --git a/src/prolog/machine/streams.rs b/src/prolog/machine/streams.rs
index 84abb488..9e6ea491 100644
--- a/src/prolog/machine/streams.rs
+++ b/src/prolog/machine/streams.rs
@@ -107,7 +107,7 @@ impl Drop for StreamInstance {
     fn drop(&mut self) {
         match self {
             StreamInstance::TcpStream(_, ref mut tcp_stream) => {
-                tcp_stream.shutdown(Shutdown::Both).unwrap();
+                discard_result!(tcp_stream.shutdown(Shutdown::Both));
             }
             _ => {
             }
diff --git a/src/prolog/machine/system_calls.rs b/src/prolog/machine/system_calls.rs
index 86f32fcb..6ba35837 100644
--- a/src/prolog/machine/system_calls.rs
+++ b/src/prolog/machine/system_calls.rs
@@ -2065,13 +2065,13 @@ impl MachineState {
                         match Number::try_from((addr, &self.heap)) {
                             Ok(Number::Integer(n)) => {
                                 if let Some(nb) = n.to_u8() {
-                                    stream.write(&mut [nb]).unwrap();
+                                    discard_result!(stream.write(&mut [nb]));
                                     return return_from_clause!(self.last_call, self);
                                 }
                             }
                             Ok(Number::Fixnum(n)) => {
                                 if let Ok(nb) = u8::try_from(n) {
-                                    stream.write(&mut [nb]).unwrap();
+                                    discard_result!(stream.write(&mut [nb]));
                                     return return_from_clause!(self.last_call, self);
                                 }
                             }