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

Inizia con l’esempio Playground collegato per riprodurre la diagnostica mancante, quindi leggi l’issue correlata #26262 sul comportamento comparabile di control-flow. Il lavoro è completo quando l’espressione che usa il risultato di una chiamata a una funzione con ritorno void segnala un errore, mentre l’esempio esistente continua a comportarsi come previsto.