If you invoke javac via CompilationTask.call, and invoke an annotation processor that calls Trees.getScope, javac will crash with IllegalStateException.

at com.sun.tools.javac.api.JavacTaskImpl.prepareCompiler(JavacTaskImpl.java:157)
at com.sun.tools.javac.api.JavacTaskImpl.enter(JavacTaskImpl.java:266)
at com.sun.tools.javac.api.JavacTrees.getAttrContext(JavacTrees.java:271)
at com.sun.tools.javac.api.JavacTrees.getScope(JavacTrees.java:230)
at com.sun.tools.javac.api.JavacTrees.getScope(JavacTrees.java:84)
at TestGetScope$Scanner.visitIdentifier(TestGetScope.java:97)
at TestGetScope$Scanner.visitIdentifier(TestGetScope.java:93)
at com.sun.tools.javac.tree.JCTree$JCIdent.accept(JCTree.java:1711)
at com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:67)
at com.sun.source.util.TreeScanner.visitAnnotation(TreeScanner.java:376)
at com.sun.tools.javac.tree.JCTree$JCAnnotation.accept(JCTree.java:2013)
at com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:67)
at com.sun.source.util.TreeScanner.scan(TreeScanner.java:90)
at com.sun.source.util.TreeScanner.visitModifiers(TreeScanner.java:372)
at com.sun.tools.javac.tree.JCTree$JCModifiers.accept(JCTree.java:2040)
at com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:67)
at com.sun.source.util.TreeScanner.visitClass(TreeScanner.java:128)
at com.sun.tools.javac.tree.JCTree$JCClassDecl.accept(JCTree.java:618)
at com.sun.source.util.TreePathScanner.scan(TreePathScanner.java:49)
at TestGetScope.process(TestGetScope.java:80)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.callProcessor(JavacProcessingEnvironment.java:752)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.discoverAndRunProcs(JavacProcessingEnvironment.java:681)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.access$1700(JavacProcessingEnvironment.java:97)
at com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.run(JavacProcessingEnvironment.java:988)
at com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1122)
at com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1106)
at com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:824)
at com.sun.tools.javac.main.Main.compile(Main.java:417)
... 9 more