RFR: 8244681: Add a warning for possibly lossy conversion in compound assignments

[Phil Race]

On Mon, 9 May 2022 15:56:35 GMT, Adam Sotona <asotona at openjdk.org> wrote:

> Please review this patch adding new lint option, **lossy-conversions**, to javac to warn about type casts in compound assignments with possible lossy conversions.
> 
> The new lint warning is shown if the type of the right-hand operand of a compound assignment is not assignment compatible with the type of the variable.
> 
> The implementation of the warning is based on similar check performed to emit "possible lossy conversion" compilation error for simple assignments. 
> 
> Proposed patch also include complex matrix-style test with positive and negative test cases of lossy conversions in compound assignments.
> 
> Proposed patch also disables this new lint option in all affected JDK modules and libraries to allow smooth JDK build. Individual cases to address possibly lossy conversions warnings in JDK are already addressed in a separate umbrella issue and its sub-tasks.
> 
> Thanks for your review,
> Adam

Marked as reviewed by prr (Reviewer).

test/langtools/tools/javac/lint/LossyConversions.java line 131:

> 129:     @SuppressWarnings("lossy-conversions")
> 130:     public void supressedLossyConversions() {
> 131:         byte a = 0;

you might want to spell suppressed correctly.

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PR: https://git.openjdk.java.net/jdk/pull/8599