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8253944: Certain method references to VarHandle methods should fail #487



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@PaulSandoz PaulSandoz commented Oct 2, 2020

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:

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.


  • Change must not contain extraneous whitespace
  • Commit message must refer to an issue
  • Change must be properly reviewed


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



$ git fetch pull/487/head:pull/487
$ git checkout pull/487

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@bridgekeeper bridgekeeper bot commented Oct 2, 2020

👋 Welcome back psandoz! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

@openjdk openjdk bot added the rfr label Oct 2, 2020
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@openjdk openjdk bot commented Oct 2, 2020

@PaulSandoz The following label will be automatically applied to this pull request:

  • compiler

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

@openjdk openjdk bot added the compiler label Oct 2, 2020
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@mlbridge mlbridge bot commented Oct 2, 2020


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@mcimadamore mcimadamore left a comment

Looks good!

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@openjdk openjdk bot commented Oct 2, 2020

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

ℹ️ This project also has non-automated pre-integration requirements. Please see the file 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

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

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

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@openjdk openjdk bot added the ready label Oct 2, 2020
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@PaulSandoz PaulSandoz commented Oct 5, 2020


@openjdk openjdk bot closed this Oct 5, 2020
@openjdk openjdk bot added integrated and removed ready rfr labels Oct 5, 2020
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@openjdk openjdk bot commented Oct 5, 2020

@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:

Your commit was automatically rebased without conflicts.

Pushed as commit b29e108.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

@PaulSandoz PaulSandoz deleted the PaulSandoz:JDK-8253944-VH-method-ref branch Oct 6, 2020
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