Java Model Exception: Error in Java Model (code 980): Index out of bounds

I'm using Eclipse 2023-EE 06 with Java 17.

I have a class `Foo` that is working. I add this at the bottom:

```java
static class Bar implements Consumer<> {

}
```

The class is literally empty. I place the cursor inside `<>` and hit `Ctrl+Space`. I guess I was hoping it would give me a list of potential types I might want to consume. (Hey, it's early here and my mind is still waking up.) In any case, I didn't expect this:

```java
eclipse.buildId=4.28.0.20230608-1200
java.version=17.0.7
java.vendor=Eclipse Adoptium
BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=en_US
Framework arguments: -product org.eclipse.epp.package.jee.product
Command-line arguments: -os win32 -ws win32 -arch x86_64 -product org.eclipse.epp.package.jee.product

org.eclipse.jdt.ui
Error
Sat Jun 24 08:39:32 PDT 2023
Internal Error

Java Model Exception: Error in Java Model (code 980): Index out of bounds
at org.eclipse.jdt.internal.core.Openable.codeComplete(Openable.java:126)
at org.eclipse.jdt.internal.core.CompilationUnit.codeComplete(CompilationUnit.java:367)
at org.eclipse.jdt.internal.core.CompilationUnit.codeComplete(CompilationUnit.java:357)
at org.eclipse.jdt.ui.text.java.JavaContentAssistInvocationContext.computeKeywordsAndContext(JavaContentAssistInvocationContext.java:307)
at org.eclipse.jdt.ui.text.java.JavaContentAssistInvocationContext.getCoreContext(JavaContentAssistInvocationContext.java:179)
at org.eclipse.jdt.internal.ui.text.java.TemplateCompletionProposalComputer.computeCompletionEngine(TemplateCompletionProposalComputer.java:74)
at org.eclipse.jdt.internal.ui.text.java.AbstractTemplateCompletionProposalComputer.computeCompletionProposals(AbstractTemplateCompletionProposalComputer.java:71)
at org.eclipse.jdt.internal.ui.text.java.CompletionProposalComputerDescriptor.computeCompletionProposals(CompletionProposalComputerDescriptor.java:348)
at org.eclipse.jdt.internal.ui.text.java.CompletionProposalCategory.computeCompletionProposals(CompletionProposalCategory.java:340)
at org.eclipse.jdt.internal.ui.text.java.ContentAssistProcessor.collectProposals(ContentAssistProcessor.java:333)
at org.eclipse.jdt.internal.ui.text.java.ContentAssistProcessor.computeCompletionProposals(ContentAssistProcessor.java:289)
at org.eclipse.jface.text.contentassist.AsyncCompletionProposalPopup.lambda$10(AsyncCompletionProposalPopup.java:378)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
at org.eclipse.jface.text.contentassist.AsyncCompletionProposalPopup.lambda$9(AsyncCompletionProposalPopup.java:377)
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1768)
at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.exec(CompletableFuture.java:1760)
at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:373)
at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1182)
at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1655)
at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1622)
at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:165)
```

I have no further information at the moment, and I cannot readily reproduce this in other classes.