diff --git a/compiler/src/dmd/hdrgen.d b/compiler/src/dmd/hdrgen.d
index b456f6cc52ca..6c9120677e85 100644
--- a/compiler/src/dmd/hdrgen.d
+++ b/compiler/src/dmd/hdrgen.d
@@ -3656,6 +3656,13 @@ const(char)* parameterToChars(Parameter parameter, TypeFunction tf, bool fullQua
 private void parametersToBuffer(ParameterList pl, ref OutBuffer buf, ref HdrGenState hgs)
 {
     buf.put('(');
+    if (pl.varargs == VarArg.KRvariadic)
+    {
+        if (!hgs.hdrgen)
+            buf.put("..."); // essentially C23 variadic with no named parameter
+        buf.put(')');
+        return;
+    }
     foreach (i; 0 .. pl.length)
     {
         if (i)
@@ -3665,12 +3672,7 @@ private void parametersToBuffer(ParameterList pl, ref OutBuffer buf, ref HdrGenS
     final switch (pl.varargs)
     {
         case VarArg.none:
-            break;
-
         case VarArg.KRvariadic:
-            // Diagnostic-only spelling; header/.di output keeps plain `()`.
-            if (!hgs.hdrgen)
-                buf.put("<K&R variadics>");
             break;
 
         case VarArg.variadic:
diff --git a/compiler/test/fail_compilation/diag23177.d b/compiler/test/fail_compilation/diag23177.d
index 2bec867df896..aa20cd7a7223 100644
--- a/compiler/test/fail_compilation/diag23177.d
+++ b/compiler/test/fail_compilation/diag23177.d
@@ -5,10 +5,10 @@
 TEST_OUTPUT:
 ---
 fail_compilation/diag23177.d(25): Error: function `run1` is not callable using argument types `(extern (C) int function())`
-fail_compilation/diag23177.d(25):        cannot pass argument `& callback` of type `extern (C) int function()` to parameter `extern (C) int function(<K&R variadics>) fn`
-fail_compilation/imports/imp23177.c(4):        `imp23177.run1(extern (C) int function(<K&R variadics>) fn)` declared here
-fail_compilation/diag23177.d(26): Error: function `run2` is not callable using argument types `(extern (C) int function(int a<K&R variadics>))`
-fail_compilation/diag23177.d(26):        cannot pass argument `& f` of type `extern (C) int function(int a<K&R variadics>)` to parameter `extern (C) int function(int a) fn`
+fail_compilation/diag23177.d(25):        cannot pass argument `& callback` of type `extern (C) int function()` to parameter `extern (C) int function(...) fn`
+fail_compilation/imports/imp23177.c(4):        `imp23177.run1(extern (C) int function(...) fn)` declared here
+fail_compilation/diag23177.d(26): Error: function `run2` is not callable using argument types `(extern (C) int function(...))`
+fail_compilation/diag23177.d(26):        cannot pass argument `& f` of type `extern (C) int function(...)` to parameter `extern (C) int function(int a) fn`
 fail_compilation/imports/imp23177.c(14):        `imp23177.run2(extern (C) int function(int a) fn)` declared here
 ---
 */