RFR: JDK-8191842: JShell: Inferred type information is lost when assigning types to a "var"

[Robert Field]

Part 2: tests

ToolSimpleTest is missing the bug number.

VariablesTest needs a copyright update.

Please add tests for:
    * anon classes with added method access
    * anon class scratch var

-Robert


On 12/13/17 13:47, Robert Field wrote:
> Nice generalization.
>
> Wrap:
>
> 90: this breaks array initialization -- this would no longer work: 
> int[] d = {1, 2, 3}
>
> Eval:
>
> 559: This code should be designed to work the same for automatically 
> created scratch variables -- aka $1, $2, ... -- they should also have 
> anonymous types.
>
> ? 322: Can ei.anonymousClasses be used rather than depending on the 
> naming added in Util.JSHELL_ANONYMOUS?
>
> 389, 419, 421, 486-493: the name "constructor" is confusing because it 
> contains other things and not the complete constructor.  One of the 
> unwritten rules of wraps in that
> they consist of a complete component, this code has several hanging 
> pieces.  Note the two closing braces in 492, braces et. al. should 
> always be matched in a wrap.
> The mixture of strings and wraps does make this challenging.
> I'd suggest doing the bodyParts/extraInit computation first, then 
> build up each component as complete entities: constructor body, class 
> body, class -- all wraps.
>
> ExpressionToTypeInfo:
>
> 355: Seems fragile to assume that the constructor is first
>
> -Robert
>
>
> On 12/13/17 02:02, Jan Lahoda wrote:
>> Hi,
>>
>> When doing:
>> var r = new Object() { String s; }
>>
>> the type of "r" is the anonymous class itself. JShell handles this by 
>> "upgrading" the anonymous class to be a member class, so that it can 
>> be properly used from other snippets.
>>
>> But JShell is not prepared for anonymous classes inside the 
>> expression (that are part of the resulting type), like:
>> ---
>> jshell> var list = Stream.of(1, 2, 3).map(j -> new Object() { int i = 
>> j; }).collect(Collectors.toList());
>>
>> jshell> list.forEach(a -> System.out.println(a.i));
>> ---
>>
>> So, part of the proposed fix is to upgrade all anonymous classes to 
>> member classes if needed. Also, intersection types are cleared from 
>> fields before writing (the intersection types are installed to ensure 
>> var semantics for cases like:
>> <Z extends Runnable & CharSequence> Z get1() { return null; }
>> var i1 = get1();
>> )
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8191842
>> Webrev: http://cr.openjdk.java.net/~jlahoda/8191842/webrev.00/
>>
>> Thanks,
>>     Jan
>>
>