diff --git a/Source/Preprocessor/cpp.c b/Source/Preprocessor/cpp.c
index 491eb8a96..47dc53b6b 100644
--- a/Source/Preprocessor/cpp.c
+++ b/Source/Preprocessor/cpp.c
@@ -817,11 +817,22 @@ static String *expand_macro(String *name, List *args, String *line_file) {
       Delete(vararg);
     }
   }
+
+  if (args && margs && Len(margs) == 1 && Len(args) == 0) {
+    /* FOO() can invoke a macro defined as FOO(X) as well as one defined FOO().
+     * Handle this by adding an empty argument to args.
+     *
+     * We don't need to worry about varargs here - a varargs macro will always have
+     * Len(margs) >= 1, since the varargs are put in the final macro argument.
+     */
+    Append(args, NewStringEmpty());
+  }
+
   /* If there are arguments, see if they match what we were given */
-  if (args && (margs) && (Len(margs) != Len(args))) {
-    if (Len(margs) > (1 + isvarargs))
+  if (args && (!margs || Len(margs) != Len(args))) {
+    if (margs && Len(margs) > (1 + isvarargs))
       Swig_error(macro_start_file, macro_start_line, "Macro '%s' expects %d arguments\n", name, Len(margs) - isvarargs);
-    else if (Len(margs) == (1 + isvarargs))
+    else if (margs && Len(margs) == (1 + isvarargs))
       Swig_error(macro_start_file, macro_start_line, "Macro '%s' expects 1 argument\n", name);
     else
       Swig_error(macro_start_file, macro_start_line, "Macro '%s' expects no arguments\n", name);
@@ -830,7 +841,7 @@ static String *expand_macro(String *name, List *args, String *line_file) {
   }
 
   /* If the macro expects arguments, but none were supplied, we leave it in place */
-  if (!args && (margs) && Len(margs) > 0) {
+  if (!args && margs) {
     macro_level--;
     return NewString(name);
   }
@@ -1156,10 +1167,6 @@ static DOH *Preprocessor_replace(DOH *s) {
 	    args = find_args(s, 1, id);
 	    macro_additional_lines = Getline(s) - line;
 	    assert(macro_additional_lines >= 0);
-	    if (!Len(args)) {
-	      Delete(args);
-	      args = 0;
-	    }
 	  } else {
 	    args = 0;
 	  }