diff --git a/vm_dump.c b/vm_dump.c
index bfb58dd..7885212 100644
--- a/vm_dump.c
+++ b/vm_dump.c
@@ -677,12 +677,15 @@ rb_vm_bugreport(void)
 	int i;
 	VALUE name;
 
-	name = vm->progname;
+	name = vm->progname; /* INV: vm->progname is always a String */
 	fprintf(stderr, "* Loaded script: %s\n", StringValueCStr(name));
 	fprintf(stderr, "\n");
 	fprintf(stderr, "* Loaded features:\n\n");
 	for (i=0; i<RARRAY_LEN(vm->loaded_features); i++) {
 	    name = RARRAY_PTR(vm->loaded_features)[i];
+	    if(TYPE(name) != T_STRING) {
+		name = rb_any_to_s(name);
+	    }
 	    fprintf(stderr, " %4d %s\n", i, StringValueCStr(name));
 	}
 	fprintf(stderr, "\n");