fix Module.RequireLoaded failure with nil module

module.go

@@ -64,7 +64,11 @@ func (s *Module) Loaded() bool {
 
 // RequireLoaded panics if the module is not loaded.
 func (s *Module) RequireLoaded() {
-	if s == nil || !s.Loaded() {
+	if s == nil {
+		panic("module is nil")
+	}
+
+	if !s.loaded {
 		panic(fmt.Sprintf("module %s not loaded", s.name))
 	}
 }