diff --git a/pkgs/racket-test-core/tests/racket/basic.rktl b/pkgs/racket-test-core/tests/racket/basic.rktl
index a33c2919a6..906adfcbd1 100644
--- a/pkgs/racket-test-core/tests/racket/basic.rktl
+++ b/pkgs/racket-test-core/tests/racket/basic.rktl
@@ -2126,6 +2126,7 @@
 (err/rt-test (raise-result-arity-error #f (expt 2 100) #f) exn:fail:contract:arity?)
 (err/rt-test (raise-result-arity-error #f (expt 2 100) "\n  in: extra") exn:fail:contract:arity?)
 (err/rt-test (raise-result-arity-error #f (expt 2 100) "\n  in: extra" 1 2 3 4 5) exn:fail:contract:arity?)
+(err/rt-test (raise-result-arity-error 'oops 5 "%") exn:fail:contract:arity?)
 
 (define (exn:fail:contract:arity?/#f e) (not (exn:fail:contract:arity? e)))
 
diff --git a/racket/src/racket/src/error.c b/racket/src/racket/src/error.c
index 762f062b7d..87154fee76 100644
--- a/racket/src/racket/src/error.c
+++ b/racket/src/racket/src/error.c
@@ -3055,7 +3055,7 @@ static Scheme_Object *raise_result_arity_error(int argc, Scheme_Object *argv[])
 
   scheme_wrong_return_arity(where, expected,
                             argc-3, got_argv,
-                            detail,
+                            (detail ? "%s" : NULL), detail,
                             NULL);
 
   return scheme_void;