diff --git a/src/common.cpp b/src/common.cpp
index 9f7d9c504..22235cdad 100644
--- a/src/common.cpp
+++ b/src/common.cpp
@@ -1935,3 +1935,17 @@ long convert_digit(wchar_t d, int base) {
 
     return res;
 }
+
+// Test if the specified character is in a range that fish uses interally to store special tokens.
+//
+// NOTE: This is used when tokenizing the input. It is also used when reading input, before
+// tokenization, to replace such chars with REPLACEMENT_WCHAR if they're not part of a quoted
+// string. We don't want external input to be able to feed reserved characters into our lexer/parser
+// or code evaluator.
+//
+// TODO: Actually implement the replacement as documented above.
+bool fish_reserved_codepoint(wchar_t c) {
+    return (c >= RESERVED_CHAR_BASE && c < RESERVED_CHAR_END) ||
+           (c >= ENCODE_DIRECT_BASE && c < ENCODE_DIRECT_END) ||
+           (c >= INPUT_COMMON_BASE && c < INPUT_COMMON_END);
+}
diff --git a/src/common.h b/src/common.h
index 0cf6a3bc0..2467b2429 100644
--- a/src/common.h
+++ b/src/common.h
@@ -776,3 +776,6 @@ long convert_digit(wchar_t d, int base);
     } while (0)
 
 #endif
+
+// Return true if the character is in a range reserved for fish's private use.
+bool fish_reserved_codepoint(wchar_t c);
diff --git a/src/reader.cpp b/src/reader.cpp
index d044a1753..88f13cee2 100644
--- a/src/reader.cpp
+++ b/src/reader.cpp
@@ -2351,20 +2351,6 @@ static int can_read(int fd) {
     return select(fd + 1, &fds, 0, 0, &can_read_timeout) == 1;
 }
 
-// Test if the specified character is in a range that fish uses interally to store special tokens.
-//
-// NOTE: This is used when tokenizing the input. It is also used when reading input, before
-// tokenization, to replace such chars with REPLACEMENT_WCHAR if they're not part of a quoted
-// string. We don't want external input to be able to feed reserved characters into our lexer/parser
-// or code evaluator.
-//
-// TODO: Actually implement the replacement as documented above.
-static int wchar_private(wchar_t c) {
-    return (c >= RESERVED_CHAR_BASE && c < RESERVED_CHAR_END) ||
-           (c >= ENCODE_DIRECT_BASE && c < ENCODE_DIRECT_END) ||
-           (c >= INPUT_COMMON_BASE && c < INPUT_COMMON_END);
-}
-
 /// Test if the specified character in the specified string is backslashed. pos may be at the end of
 /// the string, which indicates if there is a trailing backslash.
 static bool is_backslashed(const wcstring &str, size_t pos) {
@@ -2452,7 +2438,7 @@ const wchar_t *reader_readline(int nchars) {
             is_interactive_read = was_interactive_read;
             // fprintf(stderr, "C: %lx\n", (long)c);
 
-            if (((!wchar_private(c))) && (c > 31) && (c != 127)) {
+            if (((!fish_reserved_codepoint(c))) && (c > 31) && (c != 127)) {
                 if (can_read(0)) {
                     wchar_t arr[READAHEAD_MAX + 1];
                     size_t i;
@@ -2472,7 +2458,7 @@ const wchar_t *reader_readline(int nchars) {
                         // need to insert on the commandline that the commmand might need to be able
                         // to see.
                         c = input_readch(false);
-                        if ((!wchar_private(c)) && (c > 31) && (c != 127)) {
+                        if ((!fish_reserved_codepoint(c)) && (c > 31) && (c != 127)) {
                             arr[i] = c;
                             c = 0;
                         } else
@@ -3260,7 +3246,8 @@ const wchar_t *reader_readline(int nchars) {
             }
             default: {
                 // Other, if a normal character, we add it to the command.
-                if (!wchar_private(c) && (c >= L' ' || c == L'\n' || c == L'\r') && c != 0x7F) {
+                if (!fish_reserved_codepoint(c) && (c >= L' ' || c == L'\n' || c == L'\r') &&
+                    c != 0x7F) {
                     bool allow_expand_abbreviations = false;
                     if (data->is_navigating_pager_contents()) {
                         data->pager.set_search_field_shown(true);
diff --git a/src/wutil.cpp b/src/wutil.cpp
index 0461b9a38..608caf7f8 100644
--- a/src/wutil.cpp
+++ b/src/wutil.cpp
@@ -448,14 +448,6 @@ int wrename(const wcstring &old, const wcstring &newv) {
     return rename(old_narrow.c_str(), new_narrow.c_str());
 }
 
-/// Return one if the code point is in the range we reserve for internal use.
-int fish_is_reserved_codepoint(wint_t wc) {
-    if (RESERVED_CHAR_BASE <= wc && wc < RESERVED_CHAR_END) return 1;
-    if (EXPAND_RESERVED_BASE <= wc && wc < EXPAND_RESERVED_END) return 1;
-    if (WILDCARD_RESERVED_BASE <= wc && wc < WILDCARD_RESERVED_END) return 1;
-    return 0;
-}
-
 /// Return one if the code point is in a Unicode private use area.
 int fish_is_pua(wint_t wc) {
     if (PUA1_START <= wc && wc < PUA1_END) return 1;
@@ -467,7 +459,7 @@ int fish_is_pua(wint_t wc) {
 /// We need this because there are too many implementations that don't return the proper answer for
 /// some code points. See issue #3050.
 int fish_iswalnum(wint_t wc) {
-    if (fish_is_reserved_codepoint(wc)) return 0;
+    if (fish_reserved_codepoint(wc)) return 0;
     if (fish_is_pua(wc)) return 0;
     return iswalnum(wc);
 }
@@ -475,7 +467,7 @@ int fish_iswalnum(wint_t wc) {
 /// We need this because there are too many implementations that don't return the proper answer for
 /// some code points. See issue #3050.
 int fish_iswalpha(wint_t wc) {
-    if (fish_is_reserved_codepoint(wc)) return 0;
+    if (fish_reserved_codepoint(wc)) return 0;
     if (fish_is_pua(wc)) return 0;
     return iswalpha(wc);
 }
@@ -483,7 +475,7 @@ int fish_iswalpha(wint_t wc) {
 /// We need this because there are too many implementations that don't return the proper answer for
 /// some code points. See issue #3050.
 int fish_iswgraph(wint_t wc) {
-    if (fish_is_reserved_codepoint(wc)) return 0;
+    if (fish_reserved_codepoint(wc)) return 0;
     if (fish_is_pua(wc)) return 1;
     return iswgraph(wc);
 }