8253944: Certain method references to VarHandle methods should fail

[PaulSandoz]

A regression was introduced in javac when processing method references to signature polymorphic methods whose return type is not polymorphic.

It is possible to successfully target type a method reference for a VarHandle sig-poly method to a functional interface whose methods return type is incompatible with the VarHandle method. This results in a runtime linkage error rather than a source compile time error.

See the following email thread for more details:

https://mail.openjdk.java.net/pipermail/compiler-dev/2020-October/015088.html

The fix is to "patch-back" the method's return type if it is not polymorphic. As a result it was possible to simplify the inference logic and keep it focused more on inference.

---

Progress

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Issue

• JDK-8253944: Certain method references to VarHandle methods should fail

Reviewers

• Maurizio Cimadamore (@mcimadamore - Reviewer)

Download

$ git fetch https://git.openjdk.java.net/jdk pull/487/head:pull/487
$ git checkout pull/487

[bridgekeeper]

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[openjdk]

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[mlbridge]

Webrevs

• 00: Full (114a1a8)

[mcimadamore]

Looks good!

[openjdk]

@PaulSandoz This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for more details.

After integration, the commit message for the final commit will be:

8253944: Certain method references to VarHandle methods should fail

Reviewed-by: mcimadamore

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At the time when this comment was updated there had been 1 new commit pushed to the master branch:

• 123e786: 8239105: Add exception for expiring Digicert root certificates to VerifyCACerts test

Please see this link for an up-to-date comparison between the source branch of this pull request and the master branch.
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[PaulSandoz]

/integrate

[openjdk]

@PaulSandoz Since your change was applied there have been 13 commits pushed to the master branch:

• 88d75c9: 8156071: List.of: reduce array copying during creation
• ea27a54: 8224509: Incorrect alignment in CDS related allocation code on 32-bit platforms
• 4d29116: 8253433: Remove -XX:+Debugging product option
• 81dae70: 8253948: Memory leak in ImageFileReader
• 65cab55: 8253971: ZGC: Flush mark stacks after processing concurrent roots
• 19219a9: 8253960: Memory leak in Java_java_lang_ClassLoader_defineClass0()
• 5d4a135: 8253842: [JVMCI] Allow implicit exception to dispatch to other address in jvmci compilers.
• 289ae79: 8252998: ModuleWrapper.gmk doesn't consult include path
• 9604ee8: 8248238: Implementation: JEP 388: Windows AArch64 Support
• 1c2754b: 8253269: The CheckCommonColors test should provide more info on failure
• ... and 3 more: https://git.openjdk.java.net/jdk/compare/22f091608d7ea2f84fea5450bb20c29354d5e329...master

Your commit was automatically rebased without conflicts.

Pushed as commit b29e108.

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