diff --git a/src/builtins/complete.rs b/src/builtins/complete.rs
index 4014ec208..e744570f4 100644
--- a/src/builtins/complete.rs
+++ b/src/builtins/complete.rs
@@ -517,7 +517,8 @@ pub fn complete(parser: &Parser, streams: &mut IoStreams, argv: &mut [&wstr]) ->
                     next.flags,
                     faux_cmdline,
                     &mut tmp_cursor,
-                    false,
+                    /*append_only=*/ false,
+                    /*is_unique=*/ false,
                 );
 
                 // completion_apply_to_command_line will append a space unless COMPLETE_NO_SPACE
diff --git a/src/reader.rs b/src/reader.rs
index b8149c3b7..e3294f5f3 100644
--- a/src/reader.rs
+++ b/src/reader.rs
@@ -3777,6 +3777,7 @@ fn pager_selection_changed(&mut self) {
                 &self.cycle_command_line,
                 &mut cursor_pos,
                 false,
+                /*is_unique=*/ false, // don't care
             ),
         };
 
@@ -4414,6 +4415,7 @@ fn get_autosuggestion_performer(
                 &search_string,
                 &mut cursor,
                 /*append_only=*/ true,
+                /*is_unique=*/ false,
             );
         }
         result
@@ -5597,6 +5599,7 @@ pub fn completion_apply_to_command_line(
     command_line: &wstr,
     inout_cursor_pos: &mut usize,
     append_only: bool,
+    is_unique: bool,
 ) -> WString {
     let add_space = !flags.contains(CompleteFlags::NO_SPACE);
     let do_replace_token = flags.contains(CompleteFlags::REPLACES_TOKEN);
@@ -5621,7 +5624,7 @@ pub fn completion_apply_to_command_line(
     }
 
     let mut escape_flags = EscapeFlags::empty();
-    if append_only || !add_space {
+    if append_only || !is_unique || !add_space {
         escape_flags.insert(EscapeFlags::NO_QUOTED);
     }
     if no_tilde {
@@ -5869,7 +5872,12 @@ fn try_insert(&mut self, c: Completion, tok: &wstr, token_range: Range<usize>) {
         // If this is a replacement completion, check that we know how to replace it, e.g. that
         // the token doesn't contain evil operators like {}.
         if !c.flags.contains(CompleteFlags::REPLACES_TOKEN) || reader_can_replace(tok, c.flags) {
-            self.completion_insert(&c.completion, token_range.end, c.flags);
+            self.completion_insert(
+                &c.completion,
+                token_range.end,
+                c.flags,
+                /*is_unique=*/ true,
+            );
         }
     }
 
@@ -6005,7 +6013,12 @@ fn handle_completions(&mut self, token_range: Range<usize>) -> bool {
                 if prefix_is_partial_completion {
                     flags |= CompleteFlags::NO_SPACE;
                 }
-                self.completion_insert(&common_prefix, token_range.end, flags);
+                self.completion_insert(
+                    &common_prefix,
+                    token_range.end,
+                    flags,
+                    /*is_unique=*/ false,
+                );
                 self.cycle_command_line = self.command_line.text().to_owned();
                 self.cycle_cursor_pos = self.command_line.position();
             }
@@ -6049,7 +6062,13 @@ fn handle_completions(&mut self, token_range: Range<usize>) -> bool {
     /// \param token_end the position after the token to complete
     /// \param flags A union of all flags describing the completion to insert. See the completion_t
     /// struct for more information on possible values.
-    fn completion_insert(&mut self, val: &wstr, token_end: usize, flags: CompleteFlags) {
+    fn completion_insert(
+        &mut self,
+        val: &wstr,
+        token_end: usize,
+        flags: CompleteFlags,
+        is_unique: bool,
+    ) {
         let (elt, el) = self.active_edit_line();
 
         // Move the cursor to the end of the token.
@@ -6065,6 +6084,7 @@ fn completion_insert(&mut self, val: &wstr, token_end: usize, flags: CompleteFla
             el.text(),
             &mut cursor,
             /*append_only=*/ false,
+            is_unique,
         );
         self.set_buffer_maintaining_pager(&new_command_line, cursor, false);
     }
diff --git a/src/tests/complete.rs b/src/tests/complete.rs
index 21f267e30..cd6312228 100644
--- a/src/tests/complete.rs
+++ b/src/tests/complete.rs
@@ -160,7 +160,8 @@ macro_rules! unique_completion_applies_as {
                 completions[0].flags,
                 cmdline,
                 &mut cursor,
-                false,
+                /*append_only=*/ false,
+                /*is_unique=*/ true,
             );
             assert_eq!(newcmdline, L!($applied), "apply result mismatch");
         };
@@ -224,6 +225,7 @@ macro_rules! unique_completion_applies_as {
         L!("mv debug debug"),
         &mut cursor_pos,
         true,
+        /*is_unique=*/ false,
     );
     assert_eq!(newcmdline, L!("mv debug Debug/"));
 
diff --git a/src/tests/reader.rs b/src/tests/reader.rs
index 2b0450a91..be5b4ec9c 100644
--- a/src/tests/reader.rs
+++ b/src/tests/reader.rs
@@ -57,6 +57,7 @@ macro_rules! validate {
                 &line,
                 &mut cursor_pos,
                 $append_only,
+                /*is_unique=*/ false,
             );
             assert_eq!(result, expected);
             assert_eq!(cursor_pos, out_cursor_pos);
diff --git a/tests/checks/complete.fish b/tests/checks/complete.fish
index 1db09fd59..9ea39f260 100644
--- a/tests/checks/complete.fish
+++ b/tests/checks/complete.fish
@@ -10,7 +10,7 @@ complete -c complete_test_alpha3 --no-files -w 'complete_test_alpha2 extra2'
 complete -C'complete_test_alpha1 arg1 '
 # CHECK: complete_test_alpha1 arg1
 complete --escape -C'complete_test_alpha1 arg1 '
-# CHECK: 'complete_test_alpha1 arg1 '
+# CHECK: complete_test_alpha1\ arg1\{{ }}
 complete -C'complete_test_alpha2 arg2 '
 # CHECK: complete_test_alpha1 extra1 arg2
 complete -C'complete_test_alpha3 arg3 '