diff --git a/io.c b/io.c
index caef68c769..42528c0fd5 100644
--- a/io.c
+++ b/io.c
@@ -7543,7 +7543,7 @@ rb_output_fs_setter(VALUE val, ID id, VALUE *var)
 {
     rb_str_setter(val, id, &val);
     if (!NIL_P(val)) {
-        rb_warn("non-nil $, will be deprecated");
+        rb_warn_deprecated("`$,'", NULL);
     }
     *var = val;
 }
diff --git a/string.c b/string.c
index 22ced326b8..d6fd73115b 100644
--- a/string.c
+++ b/string.c
@@ -10092,7 +10092,7 @@ rb_fs_setter(VALUE val, ID id, VALUE *var)
 		 rb_id2str(id));
     }
     if (!NIL_P(val)) {
-        rb_warn("non-nil $; will be deprecated");
+        rb_warn_deprecated("`$;'", NULL);
     }
     *var = val;
 }
diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index 0276d6a14d..09d099bb4a 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -1771,7 +1771,7 @@ CODE
 
     begin
       fs = $;
-      assert_warn(/\$; will be deprecated/) {$; = " "}
+      assert_warn(/`\$;' is deprecated/) {$; = " "}
     ensure
       EnvUtil.suppress_warning {$; = fs}
     end