diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index b10c9c6467..00474a739b 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -234,10 +234,12 @@ VALUE rb_enumeratorize_with_size(VALUE, VALUE, int, const VALUE *, rb_enumerator
 #define rb_enumeratorize_with_size(obj, id, argc, argv, size_fn) \
     rb_enumeratorize_with_size(obj, id, argc, argv, (rb_enumerator_size_func *)(size_fn))
 #endif
+#define SIZED_ENUMERATOR(obj, argc, argv, size_fn) \
+    rb_enumeratorize_with_size((obj), ID2SYM(rb_frame_this_func()), \
+			       (argc), (argv), (size_fn))
 #define RETURN_SIZED_ENUMERATOR(obj, argc, argv, size_fn) do {		\
 	if (!rb_block_given_p())					\
-	    return rb_enumeratorize_with_size((obj), ID2SYM(rb_frame_this_func()),\
-				    (argc), (argv), (size_fn));		\
+	    return SIZED_ENUMERATOR(obj, argc, argv, size_fn);		\
     } while (0)
 #define RETURN_ENUMERATOR(obj, argc, argv) RETURN_SIZED_ENUMERATOR(obj, argc, argv, 0)
 /* error.c */
diff --git a/string.c b/string.c
index 4a0df2aecb..88185cfb0b 100644
--- a/string.c
+++ b/string.c
@@ -6810,7 +6810,7 @@ rb_str_enumerate_chars(VALUE str, int wantarray)
 	if (wantarray)
 	    ary = rb_ary_new_capa(str_strlen(str, enc)); /* str's enc*/
 	else
-	    RETURN_SIZED_ENUMERATOR(str, 0, 0, rb_str_each_char_size);
+	    return SIZED_ENUMERATOR(str, 0, 0, rb_str_each_char_size);
     }
 
     switch (ENC_CODERANGE(str)) {