120             @Override
 121             public Void visitCase(CaseTree node, Void p) {
 122                 if (node.getStatements() != null) {
 123                     throw new AssertionError("Unexpected statements: " + node.getStatements());
 124                 }
 125                 if (node.getBody().getKind() != Tree.Kind.BLOCK) {
 126                     throw new AssertionError("Unexpected body: " + node.getBody());
 127                 }
 128                 return super.visitCase(node, p);
 129             }
 130         }.scan(parse(code, sourceVersion), null);
 131     }
 132 
 133     private CompilationUnitTree parse(String code, String sourceVersion) throws IOException {
 134         final JavaCompiler tool = ToolProvider.getSystemJavaCompiler();
 135         assert tool != null;
 136         DiagnosticListener<JavaFileObject> noErrors = d -> {};
 137 
 138         StringWriter out = new StringWriter();
 139         JavacTask ct = (JavacTask) tool.getTask(out, null, noErrors,
 140             List.of("-XDdev", "--enable-preview", "-source", sourceVersion), null,
 141             Arrays.asList(new MyFileObject(code)));
 142         return ct.parse().iterator().next();
 143     }
 144 
 145     static class MyFileObject extends SimpleJavaFileObject {
 146         private String text;
 147 
 148         public MyFileObject(String text) {
 149             super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);
 150             this.text = text;
 151         }
 152 
 153         @Override
 154         public CharSequence getCharContent(boolean ignoreEncodingErrors) {
 155             return text;
 156         }
 157     }
 158 }

 120             @Override
 121             public Void visitCase(CaseTree node, Void p) {
 122                 if (node.getStatements() != null) {
 123                     throw new AssertionError("Unexpected statements: " + node.getStatements());
 124                 }
 125                 if (node.getBody().getKind() != Tree.Kind.BLOCK) {
 126                     throw new AssertionError("Unexpected body: " + node.getBody());
 127                 }
 128                 return super.visitCase(node, p);
 129             }
 130         }.scan(parse(code, sourceVersion), null);
 131     }
 132 
 133     private CompilationUnitTree parse(String code, String sourceVersion) throws IOException {
 134         final JavaCompiler tool = ToolProvider.getSystemJavaCompiler();
 135         assert tool != null;
 136         DiagnosticListener<JavaFileObject> noErrors = d -> {};
 137 
 138         StringWriter out = new StringWriter();
 139         JavacTask ct = (JavacTask) tool.getTask(out, null, noErrors,
 140             List.of("-XDdev"), null,
 141             Arrays.asList(new MyFileObject(code)));
 142         return ct.parse().iterator().next();
 143     }
 144 
 145     static class MyFileObject extends SimpleJavaFileObject {
 146         private String text;
 147 
 148         public MyFileObject(String text) {
 149             super(URI.create("myfo:/Test.java"), JavaFileObject.Kind.SOURCE);
 150             this.text = text;
 151         }
 152 
 153         @Override
 154         public CharSequence getCharContent(boolean ignoreEncodingErrors) {
 155             return text;
 156         }
 157     }
 158 }