On 5/14/2020 7:22 PM, Manoj Palat wrote:
I think there is a spec omission regarding "complete normally for switch
statements whose switch block consists of switch rules
Ref JLS 14 Sec 14.22
...
A switch statement whose switch block consists of switch rules can complete
normally iff at least one of the following is true:
– One of the switch rules introduces a switch rule expression (which is
necessarily a statement expression).
– One of the switch rules introduces a switch rule block that can complete
normally.
– One of the switch rules introduces a switch rule block that contains a
reachable
break statement which exits the switch statement.
...
Now consider:
switch (b) {
case 1 -> {
throw new Exception();
}
}
As per the above definition, this switch statement cannot complete normally;
but consider "b" having a value other than 1 and then it completes normally.
/* -----
To demonstrate the point, the switch statement above uses a switch rule
block that completes abruptly, but could alternatively have used a
switch rule `throw` statement:
switch (b) {
case 1 -> throw new Exception();
}
Also, to clarify for the many readers of this list, we are discussing
switch statements, which never require a `default` label. We are not
discussing switch expressions, which almost always require a `default`
label.
----- */
Also consider, 14.11.3. which says:
"If no switch label matches, the entire switch statement completes normally."
which looks inconsistent. One hand says: "completes normally" the other:
"iff at least one of the following ..." not mentioning default.
Hence, shouldn't the item,
-> – The switch block does not contain a default label.
also be added in the list in 14.22?
I agree that without a `default` switch label, 14.11.3 may evaluate "If
no switch label matches, the entire switch statement completes
normally." Since we can see a way for the statement to complete
normally, 14.22 ought to say that the statement _can_ complete normally.
So, it looks right to add "– The switch block does not contain a default
label."
Alex
