Empty `return` statement not recognized

```
func foo() {
    print("Hello World");
    return;
}

foo();
```

```
Console Output:
Error occurred: Line 3: Could not match to an expression
```

raises an error

```
func foo() {
    print("Hello World");
    return 1;
}

foo();
```

```
Console Output:
Hello World
```

works as expected
