diff --git a/internal/cli/cli.go b/internal/cli/cli.go
index 079b19e3..c0c50898 100644
--- a/internal/cli/cli.go
+++ b/internal/cli/cli.go
@@ -22,7 +22,7 @@ type Program struct {
 }
 
 func (p *Program) Execute() {
-	flag.Usage = func() { fmt.Fprintf(os.Stderr, p.Usage) }
+	flag.Usage = func() { fmt.Fprint(os.Stderr, p.Usage) }
 	flag.Parse()
 	os.Exit(p.main(flag.Args(), os.Stdin, os.Stdout, os.Stderr))
 }
diff --git a/unmarshaler.go b/unmarshaler.go
index d0df35ec..047c8b43 100644
--- a/unmarshaler.go
+++ b/unmarshaler.go
@@ -1034,7 +1034,7 @@ func (d *decoder) unmarshalInteger(value *unstable.Node, v reflect.Value) error
 	case reflect.Interface:
 		r = reflect.ValueOf(i)
 	default:
-		return unstable.NewParserError(d.p.Raw(value.Raw), d.typeMismatchString("integer", v.Type()))
+		return unstable.NewParserError(d.p.Raw(value.Raw), "%s", d.typeMismatchString("integer", v.Type()))
 	}
 
 	if !r.Type().AssignableTo(v.Type()) {
@@ -1053,7 +1053,7 @@ func (d *decoder) unmarshalString(value *unstable.Node, v reflect.Value) error {
 	case reflect.Interface:
 		v.Set(reflect.ValueOf(string(value.Data)))
 	default:
-		return unstable.NewParserError(d.p.Raw(value.Raw), d.typeMismatchString("string", v.Type()))
+		return unstable.NewParserError(d.p.Raw(value.Raw), "%s", d.typeMismatchString("string", v.Type()))
 	}
 
 	return nil