Backport: fix(ai): minor type fix (#8921)

vercel-ai-sdk[bot] · gr2m · web-flow · commit bd597883a899 · 2025-09-25T14:30:09.000-07:00
This is an automated backport of #8918 to the release-v5.0 branch. Co-authored-by: Gregor Martynus <39992+gr2m@users.noreply.github.com>
diff --git a/packages/ai/src/ui/chat.ts b/packages/ai/src/ui/chat.ts
@@ -458,7 +458,7 @@ export abstract class AbstractChat<UI_MESSAGE extends UIMessage> {
                   state,
                   output,
                   errorText,
-                } as ToolUIPart<InferUIMessageTools<UI_MESSAGE>>)
+                } as typeof part)
               : part,
           );
       }

Original file line number	Diff line number	Diff line change
`@@ -458,7 +458,7 @@ export abstract class AbstractChat<UI_MESSAGE extends UIMessage> {`
`458`	`458`	`state,`
`459`	`459`	`output,`
`460`	`460`	`errorText,`
`461`		`- } as ToolUIPart<InferUIMessageTools<UI_MESSAGE>>)`
	`461`	`+ } as typeof part)`
`462`	`462`	`: part,`
`463`	`463`	`);`
`464`	`464`	`}`