typetools / typetools/checker-framework

Aliasing Checker : Returning @Unique object does not raise an error

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Dominant language
Java
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Description

Consider the code given below.

@Unique
class Data {

    Object check(Data p) { return p; }   // No error

    Object check2(@Unique Data p) { return p; }   // No error

}

When the code is compiled by the Aliasing Checker, it doesn't raise any error even when the object is explicitly annotated.

Shouldn't it ideally raise an error in the return p line, since Data p is @Unique and is now leaked?

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  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by compiling the Java example with the Aliasing Checker and inspect how the two return statements are diagnosed. Compare the behavior for Data p and @Unique Data p; done means the explicitly annotated case reports the suspected uniqueness leak if that expectation is confirmed.

Written by the indexing model from the issue text.

Assessment

Tech stack
java
Domain
devtools
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
40/100

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