diff --git a/fish-rust/src/builtins/argparse.rs b/fish-rust/src/builtins/argparse.rs
index d18dac750..3fd179b3e 100644
--- a/fish-rust/src/builtins/argparse.rs
+++ b/fish-rust/src/builtins/argparse.rs
@@ -12,7 +12,7 @@ use crate::ffi::Repin;
 use crate::wchar::{wstr, WString, L};
 use crate::wchar_ext::WExt;
 use crate::wcstringutil::split_string;
-use crate::wgetopt::{wgetopter_t, wopt, woption, woption_argument_t};
+use crate::wgetopt::{wgetopter_t, wopt, woption, woption_argument_t, NONOPTION_CHAR_CODE};
 use crate::wutil::{fish_iswalnum, fish_wcstol, wgettext_fmt};
 use libc::c_int;
 
@@ -832,7 +832,7 @@ fn argparse_parse_flags<'args>(
                     STATUS_CMD_OK
                 }
             }
-            '\u{1}' => {
+            NONOPTION_CHAR_CODE => {
                 // A non-option argument.
                 // We use `-` as the first option-string-char to disable GNU getopt's reordering,
                 // otherwise we'd get ignored options first and normal arguments later.
diff --git a/fish-rust/src/wgetopt.rs b/fish-rust/src/wgetopt.rs
index bc4224c98..8caddfe73 100644
--- a/fish-rust/src/wgetopt.rs
+++ b/fish-rust/src/wgetopt.rs
@@ -54,6 +54,9 @@ enum Ordering {
     RETURN_IN_ORDER,
 }
 
+/// The special character code, enabled via RETURN_IN_ORDER, indicating a non-option argument.
+pub const NONOPTION_CHAR_CODE: char = '\x01';
+
 impl Default for Ordering {
     fn default() -> Self {
         Ordering::PERMUTE
@@ -323,7 +326,7 @@ impl<'opts, 'args, 'argarray> wgetopter_t<'opts, 'args, 'argarray> {
             }
             self.woptarg = Some(self.argv[self.woptind]);
             self.woptind += 1;
-            return Some(char::from(1));
+            return Some(NONOPTION_CHAR_CODE);
         }
 
         // We have found another option-ARGV-element. Skip the initial punctuation.