diff --git a/src/machine/dispatch.rs b/src/machine/dispatch.rs
index ba13cf5b..11e6d95d 100644
--- a/src/machine/dispatch.rs
+++ b/src/machine/dispatch.rs
@@ -2376,6 +2376,20 @@ impl Machine {
                         (HeapCellValueTag::Char) => {
                             self.machine_st.p += 1;
                         }
+                        (HeapCellValueTag::Cons, c) => {
+                            match_untyped_arena_ptr!(c,
+                               (ArenaHeaderTag::Stream, stream) => {
+                                   if stream.options().get_alias().is_none() {
+                                       self.machine_st.backtrack();
+                                   } else {
+                                       self.machine_st.p += 1;
+                                   }
+                               }
+                               _ => {
+                                   self.machine_st.backtrack();
+                               }
+                            );
+                        }
                         _ => {
                             self.machine_st.backtrack();
                         }
@@ -2405,6 +2419,20 @@ impl Machine {
                         (HeapCellValueTag::Char) => {
                             self.machine_st.p = self.machine_st.cp;
                         }
+                        (HeapCellValueTag::Cons, c) => {
+                            match_untyped_arena_ptr!(c,
+                               (ArenaHeaderTag::Stream, stream) => {
+                                   if stream.options().get_alias().is_none() {
+                                       self.machine_st.backtrack();
+                                   } else {
+                                       self.machine_st.p = self.machine_st.cp;
+                                   }
+                               }
+                               _ => {
+                                   self.machine_st.backtrack();
+                               }
+                            );
+                        }
                         _ => {
                             self.machine_st.backtrack();
                         }