diff --git a/types/test.ts b/types/test.ts
index f49483fc7..372a448e2 100644
--- a/types/test.ts
+++ b/types/test.ts
@@ -92,7 +92,7 @@ const parsedTmplWithoutOptions = Handlebars.parse('<p>Hello, my name is {{name}}
 
 // Custom partial resolution.
 const originalResolvePartial = Handlebars.VM.resolvePartial;
-Handlebars.VM.resolvePartial = (partial, context, options) => {
+Handlebars.VM.resolvePartial = <T>(partial: HandlebarsTemplateDelegate<T> | undefined, context: any, options: RuntimeOptions): HandlebarsTemplateDelegate<T> => {
   const name = options.name;
   // transform name.
   options.name = name;