TypeScript Version: 3.7.2 (playground)

Search Terms: generator implicitAny

Code

function* generator() {
    const value = yield;
    console.log(value);
}

const iterator = generator();
iterator.next();
iterator.next(5);

Expected behavior:
TypeScript Compiler with enabled noImplicitAny flag warns about implicit any with yield expression assignment.

function* generator() {
    const value: ExpectedType = yield call(fn); // Example from redux-saga
}

Actual behavior:
Yield expression is assigned implicitly as any because we're not able to infer the type. While I acknowledge that proper type check here is a difficult issue with quite a few other issues open, we should be forced to declare the expected type.

Playground Link

Related Issues:

• #32523