diff --git a/packages/node_modules/overmind/src/internalTypes.ts b/packages/node_modules/overmind/src/internalTypes.ts
index 342caa14..9a668a91 100644
--- a/packages/node_modules/overmind/src/internalTypes.ts
+++ b/packages/node_modules/overmind/src/internalTypes.ts
@@ -6,9 +6,9 @@ export type SubType<Base, Condition> = Pick<
   { [Key in keyof Base]: Base[Key] extends Condition ? Key : never }[keyof Base]
 >
 
-export type NestedPartial<T> = T extends object
-  ? Partial<{ [P in keyof T]: NestedPartial<T[P]> }>
-  : T
+export type NestedPartial<T> = T extends Function
+  ? T
+  : Partial<{ [P in keyof T]: NestedPartial<T[P]> }>
 
 export type Options = {
   name?: string