Class declaration in method causes crash with -Ainfer

[jwaataja]

This bug was introduced by #3441. I get a crash when a class is declared inside a method with -Ainfer.

public class ClassInMethod {
    public void method() {
        class Inner {
            Object o = null;
        }
    }
}

$CHECKERFRAMEWORK/checker/bin/javac -processor Nullnesschecker -Ainfer=stubs ClassInMethod.java

error: SourceChecker.typeProcess: unexpected Throwable (ClassCastException) while processing ClassInMethod.java; message: class com.sun.tools.javac.code.Symbol$MethodSymbol cannot be cast to class javax.lang.model.element.TypeElement (com.sun.tools.javac.code.Symbol$MethodSymbol is in module jdk.compiler of loader 'app'; javax.lang.model.element.TypeElement is in module java.compiler of loader 'platform')
  ; The Checker Framework crashed.  Please report the crash.
  Compilation unit: ClassInMethod.java
  Last visited tree at line 4 column 24:
              Object o = null;
  Exception: java.lang.ClassCastException: class com.sun.tools.javac.code.Symbol$MethodSymbol cannot be cast to class javax.lang.model.element.TypeElement (com.sun.tools.javac.code.Symbol$MethodSymbol is in module jdk.compiler of loader 'app'; javax.lang.model.element.TypeElement is in module java.compiler of loader 'platform'); java.lang.ClassCastException: class com.sun.tools.javac.code.Symbol$MethodSymbol cannot be cast to class javax.lang.model.element.TypeElement (com.sun.tools.javac.code.Symbol$MethodSymbol is in module jdk.compiler of loader 'app'; javax.lang.model.element.TypeElement is in module java.compiler of loader 'platform')
  	at org.checkerframework.common.wholeprograminference.SceneToStubWriter.getTypeElementsForClasses(SceneToStubWriter.java:509)
  	at org.checkerframework.common.wholeprograminference.SceneToStubWriter.printClassDefinitions(SceneToStubWriter.java:465)
  	at org.checkerframework.common.wholeprograminference.SceneToStubWriter.printClass(SceneToStubWriter.java:715)
  	at org.checkerframework.common.wholeprograminference.SceneToStubWriter.writeImpl(SceneToStubWriter.java:655)
  	at org.checkerframework.common.wholeprograminference.SceneToStubWriter.write(SceneToStubWriter.java:92)
  	at org.checkerframework.common.wholeprograminference.scenelib.ASceneWrapper.writeToFile(ASceneWrapper.java:147)
  	at org.checkerframework.common.wholeprograminference.WholeProgramInferenceScenesStorage.writeScenes(WholeProgramInferenceScenesStorage.java:110)
  	at org.checkerframework.common.wholeprograminference.WholeProgramInferenceScenes.writeResultsToFile(WholeProgramInferenceScenes.java:438)
  	at org.checkerframework.framework.type.AnnotatedTypeFactory.postProcessClassTree(AnnotatedTypeFactory.java:1123)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.visitClass(BaseTypeVisitor.java:328)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.visitClass(BaseTypeVisitor.java:166)
  	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:808)
  	at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:82)
  	at org.checkerframework.framework.source.SourceVisitor.scan(SourceVisitor.java:88)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.scan(BaseTypeVisitor.java:289)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.scan(BaseTypeVisitor.java:166)
  	at jdk.compiler/com.sun.source.util.TreeScanner.scan(TreeScanner.java:105)
  	at jdk.compiler/com.sun.source.util.TreeScanner.visitBlock(TreeScanner.java:248)
  	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCBlock.accept(JCTree.java:1032)
  	at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:82)
  	at org.checkerframework.framework.source.SourceVisitor.scan(SourceVisitor.java:88)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.scan(BaseTypeVisitor.java:289)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.scan(BaseTypeVisitor.java:166)
  	at jdk.compiler/com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:90)
  	at jdk.compiler/com.sun.source.util.TreeScanner.visitMethod(TreeScanner.java:206)
  	at org.checkerframework.framework.source.SourceVisitor.visitMethod(SourceVisitor.java:106)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.visitMethod(BaseTypeVisitor.java:732)
  	at org.checkerframework.checker.initialization.InitializationVisitor.visitMethod(InitializationVisitor.java:333)
  	at org.checkerframework.checker.initialization.InitializationVisitor.visitMethod(InitializationVisitor.java:51)
  	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCMethodDecl.accept(JCTree.java:898)
  	at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:82)
  	at org.checkerframework.framework.source.SourceVisitor.scan(SourceVisitor.java:88)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.scan(BaseTypeVisitor.java:289)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.scan(BaseTypeVisitor.java:166)
  	at jdk.compiler/com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:90)
  	at jdk.compiler/com.sun.source.util.TreeScanner.scan(TreeScanner.java:105)
  	at jdk.compiler/com.sun.source.util.TreeScanner.scanAndReduce(TreeScanner.java:113)
  	at jdk.compiler/com.sun.source.util.TreeScanner.visitClass(TreeScanner.java:187)
  	at org.checkerframework.framework.source.SourceVisitor.visitClass(SourceVisitor.java:94)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.processClassTree(BaseTypeVisitor.java:374)
  	at org.checkerframework.checker.initialization.InitializationVisitor.processClassTree(InitializationVisitor.java:293)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.visitClass(BaseTypeVisitor.java:327)
  	at org.checkerframework.common.basetype.BaseTypeVisitor.visitClass(BaseTypeVisitor.java:166)
  	at jdk.compiler/com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:808)
  	at jdk.compiler/com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:56)
  	at org.checkerframework.framework.source.SourceVisitor.visit(SourceVisitor.java:82)
  	at org.checkerframework.framework.source.SourceChecker.typeProcess(SourceChecker.java:901)
  	at org.checkerframework.common.basetype.BaseTypeChecker.typeProcess(BaseTypeChecker.java:512)
  	at org.checkerframework.javacutil.AbstractTypeProcessor$AttributionTaskListener.finished(AbstractTypeProcessor.java:190)
  	at jdk.compiler/com.sun.tools.javac.api.ClientCodeWrapper$WrappedTaskListener.finished(ClientCodeWrapper.java:828)
  	at jdk.compiler/com.sun.tools.javac.api.MultiTaskListener.finished(MultiTaskListener.java:132)
  	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1418)
  	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.flow(JavaCompiler.java:1375)
  	at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:973)
  	at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:311)
  	at jdk.compiler/com.sun.tools.javac.main.Main.compile(Main.java:170)
  	at jdk.compiler/com.sun.tools.javac.Main.compile(Main.java:57)
  	at jdk.compiler/com.sun.tools.javac.Main.main(Main.java:43)
ClassInMethod.java:4: error: [assignment.type.incompatible] incompatible types in assignment.
            Object o = null;
                       ^
  found   : null
  required: @Initialized @NonNull Object
2 errors