Circular inference failure (regression) #16512

TypeScript Version: 2.5.0-dev.20170613

Code

I tried to make a simple repro but it failed. I had to add the annotation as follows. The previous code was working until 2.4.0-dev.20170606.

falsandtru/pjax-api@f5dbc6d

-  .extract(parser => (html: string) => Just(parser(html)));
+  .extract(parser => (html: string): Maybe<Document> => Just(parser(html)));

Expected behavior:

no error

Actual behavior:

TypeScript error: src/lib/html.ts(9,22): Error TS7024: Function implicitly has return type 'any' because it does not have a return type annotation and is referenced directly or indirectly in one of its return expressions.