implementation of record constructor auto-initialization [was Re: instance initializer]

[Vicente Romero]

I think that according to what we have discussed here this example 
included in the spec will have to be modified:

|record NonNegativePoint(int i, int j) { public NonNegativePoint { if ( 
i < 0 ) i = Math.abs(i); //should be this.i = ... if ( j < 0 ) j = 
Math.abs(j); // should be this.j = ... } }|

as neither `i` nor `j` are DU for all exit paths

Vicente

On 9/6/19 11:11 AM, Brian Goetz wrote:
> Given than most users don’t even realize you can say `return` in a constructor, this seems a reasonable restriction.  The whole point of a compact ctor is to NOT have to specify the field initialization.
>
>> On Sep 6, 2019, at 10:53 AM, Maurizio Cimadamore <maurizio.cimadamore at oracle.com> wrote:
>>
>>
>> On 06/09/2019 15:45, Brian Goetz wrote:
>>>> Actually - not sure - what do you mean by "exit path"? We clearly can't have "returns" here. And, if we "throw" then we don't care much about initializing.
>>>>
>>>>
>>> Returns are exactly what I was concerned about; currently return is allowed, though weird, in ctors.
>>>
>>> If you want to say “no return in compact ctor”, that’s a reasonable simplification (though we’ll battle this beast again later when we want to expand some of the compact-ctor goodies to more general class constructors.)
>>>
>> I think I'd slightly prefer it to restrict it that way - not out of compiler complexity (as I said, a try/catch should be enough to handle it) - but out of managing user expectations.
>>
>> Maurizio
>>