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Type: Enhancement
Resolution: Fixed
Priority: P4
Fix Version/s: 7
Affects Version/s: 7
Component/s: specification
Labels:
None

Subcomponent:
language
Resolved In Build:
rc
CPU:

generic
OS:

generic
Verification:
Verified

JLS 15.12.2.7 generates but does not use supertype constraints of the form S>>T. Such a constraint arises if a formal parameter uses '? super T'. If T is not inferred by 15.12.2.7, then 15.12.2.8 takes over and (in many cases) generates Object>>T. This is not wrong, but is imprecise. There is no reason why the JLS shouldn't propagate the >> constraints from 15.12.2.7 to 15.12.2.8. Also, as per 6650759, it is desirable to propagate == constraints. 15.12.2.8 could say:

"Then, a set of initial constraints consisting of:
- the constraint S >> R'...
- additional constraints Bi[T1=B(T1)..Tn=B(Tn)] >> Ti, where ...
***- for any constraint of the form V >> Ti generated in 15.12.2.7: a constraint V[T1=B(T1)..Tn=B(Tn)] >> Ti***
***- for any constraint of the form Ti == V generated in 15.12.2.7: a constraint Ti == V[T1=B(T1)..Tn=B(Tn)]***"

relates to

JDK-6638712 Inference with wildcard types causes selection of inapplicable method

Closed

JDK-6707034 javac accepts method invocation with actuals that are not subtypes of the formal

Closed

JDK-6476073 Capture using super wildcard of type variables doesn't work

Closed

JDK-6650759 Inference of formal type parameter (unused in formal parameters) is not performed

Closed

JDK-6357966 parameters containing nested generic types avoid recursive calls

Closed

JDK-6811943 inference: javac 1.6 & Eclipse infer more types than JLS (umbrella CR)

Closed

(1 relates to)

Assignee:: Alex Buckley

Reporter:: Alex Buckley

Votes:: 0 Vote for this issue

Watchers:: 1 Start watching this issue

Created:: 2007-12-11 12:12

Updated:: 2014-08-01 12:50

Resolved:: 2011-07-21 15:09

Imported:: 16/Sep/12 7:25 PM

Indexed:: 18/Jul/12 1:58 PM

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