8261606: Surprising behavior of step over in String switch

Reviewed-by: vromero

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Lower.java

@@ -3877,7 +3877,9 @@ public class Lower extends TreeTranslator {
 
                 stmtList.append(switch2);
 
-                return make.Block(0L, stmtList.toList());
+                JCBlock res = make.Block(0L, stmtList.toList());
+                res.endpos = TreeInfo.endPos(tree);
+                return res;
             } else {
                 JCSwitchExpression switch2 = make.SwitchExpression(make.Ident(dollar_tmp), lb.toList());
 

src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java

@@ -2821,6 +2821,7 @@ public class JavacParser implements Parser {
             accept(LBRACE);
             List<JCCase> cases = switchBlockStatementGroups();
             JCSwitch t = to(F.at(pos).Switch(selector, cases));
+            t.endpos = token.endPos;
             accept(RBRACE);
             return t;
         }

src/jdk.compiler/share/classes/com/sun/tools/javac/tree/JCTree.java

@@ -1246,6 +1246,8 @@ public abstract class JCTree implements Tree, Cloneable, DiagnosticPosition {
     public static class JCSwitch extends JCStatement implements SwitchTree {
         public JCExpression selector;
         public List<JCCase> cases;
+        /** Position of closing brace, optional. */
+        public int endpos = Position.NOPOS;
         protected JCSwitch(JCExpression selector, List<JCCase> cases) {
             this.selector = selector;
             this.cases = cases;

src/jdk.compiler/share/classes/com/sun/tools/javac/tree/TreeInfo.java

@@ -427,6 +427,9 @@ public class TreeInfo {
             JCTry t = (JCTry) tree;
             return endPos((t.finalizer != null) ? t.finalizer
                           : (t.catchers.nonEmpty() ? t.catchers.last().body : t.body));
+        } else if (tree.hasTag(SWITCH) &&
+                   ((JCSwitch) tree).endpos != Position.NOPOS) {
+            return ((JCSwitch) tree).endpos;
         } else if (tree.hasTag(SWITCH_EXPRESSION) &&
                    ((JCSwitchExpression) tree).endpos != Position.NOPOS) {
             return ((JCSwitchExpression) tree).endpos;

test/langtools/tools/javac/classfiles/attributes/LineNumberTable/StringSwitchBreaks.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright (c) 2021, 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 8261606
+ * @summary Tests a line number table attribute for language constructions in different containers.
+ * @library /tools/lib /tools/javac/lib ../lib
+ * @modules jdk.compiler/com.sun.tools.javac.api
+ *          jdk.compiler/com.sun.tools.javac.main
+ *          jdk.compiler/com.sun.tools.javac.util
+ *          jdk.jdeps/com.sun.tools.classfile
+ * @build toolbox.ToolBox InMemoryFileManager TestBase
+ * @build LineNumberTestBase TestCase
+ * @run main StringSwitchBreaks
+ */
+
+import java.util.List;
+
+public class StringSwitchBreaks extends LineNumberTestBase {
+    public static void main(String[] args) throws Exception {
+        new StringSwitchBreaks().test();
+    }
+
+    public void test() throws Exception {
+        test(List.of(TEST_CASE));
+    }
+
+    private static final TestCase[] TEST_CASE = new TestCase[] {
+        new TestCase("""
+                     public class StringSwitchBreaks {                     // 1
+                         private void test(String s) {                     // 2
+                             if (s != null) {                              // 3
+                                 switch (s) {                              // 4
+                                     case "a":                             // 5
+                                         System.out.println("a");          // 6
+                                         break;                            // 7
+                                     default:                              // 8
+                                         System.out.println("default");    // 9
+                                 }                                         //10
+                             } else {                                      //11
+                                 System.out.println("null");               //12
+                             }                                             //13
+                         }                                                 //14
+                     }                                                     //15
+                     """,
+                     List.of(1, 3, 4, 6, 7, 9, 10, 12, 14),
+                     "StringSwitchBreaks")
+    };
+
+}