Should disallow using the result of calling a void-returning function

TypeScript Version: 4.1.0-dev.20201008

Search Terms: disallow function call void return usage warn error

Code

function doesntReturn() {
    // no return statement
}

const foo: string = doesntReturn() + 'foo'; // should be an error

Expected behavior:

The expression doesntReturn() + 'foo' should be an error because it uses the value of a void-returning function call. As far as I can tell, there is literally no good reason to use the return value of a function with no return statements like this.

This is similar to the current behavior of disallowing void-returning expressions inside control flow (issue #26262). It is also similar to the reasoning behind the warning that occurs when using a function value (instead of calling it) in an if condition.

Actual behavior:

No error message is given.

Playground Link: here

Related Issues: #26262

Start with the linked Playground example to reproduce the missing diagnostic, then read related issue #26262 for the comparable control-flow behavior. Done means the expression that uses the result of a void-returning function call reports an error, while the existing example continues to behave as expected.