diff -r 88502b1cf76f -r 7799a51dbe30 test/langtools/tools/javac/patterns/PatternMatchPosTest.java
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/tools/javac/patterns/PatternMatchPosTest.java	Wed Nov 27 09:00:01 2019 +0100
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/*
+ * @test
+ * @bug 8231827
+ * @summary Check proper positions.
+ * @build PatternMatchPosTest
+ * @compile/ref=PatternMatchPosTest.out -processor PatternMatchPosTest -Xlint:unchecked -XDrawDiagnostics --enable-preview -source ${jdk.version} PatternMatchPosTestData.java
+ */
+
+import java.io.IOException;
+import java.util.Set;
+
+import javax.annotation.processing.AbstractProcessor;
+import javax.annotation.processing.RoundEnvironment;
+import javax.annotation.processing.SupportedAnnotationTypes;
+import javax.lang.model.SourceVersion;
+import javax.lang.model.element.TypeElement;
+
+import com.sun.source.tree.IfTree;
+import com.sun.source.tree.Tree;
+import com.sun.source.util.SourcePositions;
+import com.sun.source.util.TreePath;
+import com.sun.source.util.TreeScanner;
+import com.sun.source.util.Trees;
+import javax.tools.Diagnostic;
+
+@SupportedAnnotationTypes("*")
+public class PatternMatchPosTest extends AbstractProcessor {
+
+    int round;
+
+    @Override
+    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+        if (round++ != 0)
+            return false;
+
+        try {
+            TypeElement data = processingEnv.getElementUtils().getTypeElement("PatternMatchPosTestData");
+            Trees trees = Trees.instance(processingEnv);
+            SourcePositions sp = trees.getSourcePositions();
+            TreePath dataPath = trees.getPath(data);
+            String text = dataPath.getCompilationUnit().getSourceFile().getCharContent(true).toString();
+
+            new TreeScanner<Void, Void>() {
+                boolean print;
+                @Override
+                public Void visitIf(IfTree node, Void p) {
+                    boolean prevPrint = print;
+                    try {
+                        print = true;
+                        scan(node.getCondition(), p);
+                    } finally {
+                        print = prevPrint;
+                    }
+                    scan(node.getThenStatement(), p);
+                    scan(node.getElseStatement(), p);
+                    return null;
+                }
+                @Override
+                public Void scan(Tree tree, Void p) {
+                    if (tree == null)
+                        return null;
+                    if (print) {
+                        int start = (int) sp.getStartPosition(dataPath.getCompilationUnit(), tree);
+                        int end = (int) sp.getEndPosition(dataPath.getCompilationUnit(), tree);
+                        processingEnv.getMessager().printMessage(Diagnostic.Kind.NOTE,
+                                                                 text.substring(start, end));
+                    }
+                    return super.scan(tree, p);
+                }
+            }.scan(dataPath.getLeaf(), null);
+            return false;
+        } catch (IOException ex) {
+            throw new IllegalStateException(ex);
+        }
+    }
+
+    @Override
+    public SourceVersion getSupportedSourceVersion() {
+        return SourceVersion.latestSupported();
+    }
+
+}