Unexpected error (java.lang.AssertionError)

### Apache NetBeans version

Apache NetBeans 29

### What happened

```
java.lang.AssertionError
at com.sun.tools.javac.util.Assert.error(Assert.java:155)
at com.sun.tools.javac.util.Assert.check(Assert.java:46)
at com.sun.tools.javac.comp.Attr.attribClassBody(Attr.java:5596)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:5557)
at com.sun.tools.javac.comp.Attr.attribClass(Attr.java:5373)
at org.netbeans.lib.nbjavac.services.NBAttr.attribClass(NBAttr.java:74)
at com.sun.tools.javac.comp.Attr.visitClassDef(Attr.java:983)
at org.netbeans.lib.nbjavac.services.NBAttr.visitClassDef(NBAttr.java:80)
at com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:866)
at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:679)
at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:753)
at com.sun.tools.javac.comp.Attr.visitAnonymousClassDefinition(Attr.java:3034)
at com.sun.tools.javac.comp.Attr.visitNewClass(Attr.java:2918)
at com.sun.tools.javac.tree.JCTree$JCNewClass.accept(JCTree.java:1931)
at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:679)
at com.sun.tools.javac.comp.Attr.attribExpr(Attr.java:725)
at com.sun.tools.javac.comp.Attr.visitVarDef(Attr.java:1315)
at org.netbeans.lib.nbjavac.services.NBAttr.visitVarDef(NBAttr.java:99)
at com.sun.tools.javac.tree.JCTree$JCVariableDecl.accept(JCTree.java:1082)
at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:679)
at com.sun.tools.javac.comp.Attr.attribStat(Attr.java:753)
at com.sun.tools.javac.comp.Attr.attribStats(Attr.java:772)
at com.sun.tools.javac.comp.Attr.visitBlock(Attr.java:1461)
at org.netbeans.lib.nbjavac.services.NBAttr.visitBlock(NBAttr.java:92)
at com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1152)
at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:679)
at com.sun.tools.javac.comp.DeferredAttr.attribSpeculative(DeferredAttr.java:515)
at com.sun.tools.javac.comp.Attr.attribToTree(Attr.java:430)
at com.sun.tools.javac.comp.Attr.attribStatToTree(Attr.java:423)
at com.sun.tools.javac.api.JavacTrees.attribStatToTree(JavacTrees.java:906)
at com.sun.tools.javac.api.JavacTrees.getAttrContext(JavacTrees.java:881)
at com.sun.tools.javac.api.JavacTrees.getScope(JavacTrees.java:747)
at org.netbeans.lib.nbjavac.services.NBJavacTrees.getScope(NBJavacTrees.java:110)
at org.netbeans.lib.nbjavac.services.NBJavacTrees.getScope(NBJavacTrees.java:48)
at org.netbeans.api.java.source.TreeUtilities.scopeFor(TreeUtilities.java:871)
at org.netbeans.modules.debugger.jpda.projects.PreferredCCParser$ParseExpressionTask.run(PreferredCCParser.java:592)
at org.netbeans.modules.debugger.jpda.projects.PreferredCCParser$ParseExpressionTask$2.call(PreferredCCParser.java:564)
at org.netbeans.modules.debugger.jpda.projects.PreferredCCParser$ParseExpressionTask$2.call(PreferredCCParser.java:561)
at org.netbeans.modules.debugger.jpda.projects.PreferredCCParser.runGuarded(PreferredCCParser.java:747)
at org.netbeans.modules.debugger.jpda.projects.PreferredCCParser$ParseExpressionTask.parse(PreferredCCParser.java:561)
at org.netbeans.modules.debugger.jpda.projects.PreferredCCParser.interpretOrCompileCode(PreferredCCParser.java:439)
at org.netbeans.modules.debugger.jpda.projects.EditorContextSupport.interpretOrCompileCode(EditorContextSupport.java:1436)
at org.netbeans.modules.debugger.jpda.projectsui.EditorContextImpl.interpretOrCompileCode(EditorContextImpl.java:825)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
[catch] at org.netbeans.modules.debugger.jpda.EditorContextBridge.interpretOrCompileCode(EditorContextBridge.java:111)
at org.netbeans.modules.debugger.jpda.expr.TreeEvaluator.evaluate(TreeEvaluator.java:179)
at org.netbeans.modules.debugger.jpda.JavaEvaluator.evaluateIn(JavaEvaluator.java:147)
at org.netbeans.modules.debugger.jpda.JavaEvaluator.evaluate(JavaEvaluator.java:95)
at org.netbeans.modules.debugger.jpda.expr.EvaluatorExpression.evaluate(EvaluatorExpression.java:53)
at org.netbeans.modules.debugger.jpda.JPDADebuggerImpl.evaluateGeneric(JPDADebuggerImpl.java:967)
at org.netbeans.modules.debugger.jpda.JPDADebuggerImpl.evaluate(JPDADebuggerImpl.java:353)
at org.netbeans.modules.debugger.jpda.JPDADebuggerImpl.evaluate(JPDADebuggerImpl.java:317)
at org.netbeans.modules.debugger.jpda.ui.models.InlineValueComputerImpl.lambda$refreshVariables$1(InlineValueComputerImpl.java:206)
at java.base/java.util.HashMap.computeIfAbsent(HashMap.java:1229)
at org.netbeans.modules.debugger.jpda.ui.models.InlineValueComputerImpl.lambda$refreshVariables$3(InlineValueComputerImpl.java:204)
at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1403)
at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:45)
at org.openide.util.lookup.Lookups.executeWith(Lookups.java:287)
at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2012)
```

### Language / Project Type / NetBeans Component

java ant project

### How to reproduce

You just need to use NetBeans for a certain amount of time.

### Did this work correctly in an earlier version?

No / Don't know

### Operating System

Linux 6.4.0-150600.23.81-default #1 SMP PREEMPT_DYNAMIC

### JDK

Product Version: Apache NetBeans IDE 29 Java: 24.0.2; OpenJDK 64-Bit Server VM 24.0.2+12 Runtime: OpenJDK Runtime Environment 24.0.2+12

### Apache NetBeans packaging

Apache NetBeans binary zip

### Anything else

Sources are Java 8

### Are you willing to submit a pull request?

No

The stack trace points through org.netbeans.modules.debugger.jpda.projects.PreferredCCParser, EditorContextSupport, and org.netbeans.lib.nbjavac.services.NBAttr; begin by reproducing the debugger expression evaluation that triggers it. Trace the Java 24 and Java 8-source path into Attr.attribClassBody and identify a stable trigger. Done means evaluation no longer raises AssertionError and the failure is covered by an appropriate debugger test.

Written by the indexing model from the issue text.