changeset 55641:4a03245ffc2f

8220041: NullPointerException at jdk.compiler/com.sun.tools.javac.jvm.Code.emitop0 Summary: LambdaToMethod must correctly capture local variables inside switch expressions inside local variable initializers. Reviewed-by: mcimadamore, vromero
author jlahoda
date Wed, 10 Jul 2019 09:04:42 +0200
parents 3081f39a3d30
children 66cf6a8318e4
files src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java test/langtools/tools/javac/switchexpr/LambdaCapture.java
diffstat 2 files changed, 111 insertions(+), 2 deletions(-) [+]
line wrap: on
line diff
--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java	Wed Jul 10 09:43:35 2019 +0800
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/LambdaToMethod.java	Wed Jul 10 09:04:42 2019 +0200
@@ -1709,8 +1709,9 @@
                         }
                         break;
                     case VARDEF:
-                        if (((JCVariableDecl)block.tree).sym == sym &&
-                                sym.owner.kind == MTH) { //only locals are captured
+                        if ((((JCVariableDecl)block.tree).sym == sym &&
+                                sym.owner.kind == MTH) || //only locals are captured
+                            (block.locals != null && block.locals.contains(sym))) {
                             return currentDepth > depth ? null : block.tree;
                         }
                         break;
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/tools/javac/switchexpr/LambdaCapture.java	Wed Jul 10 09:04:42 2019 +0200
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 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 8220041
+ * @summary Verify variable capture works inside switch expressions which are
+ *          inside variable declarations
+ * @compile --enable-preview -source ${jdk.version} LambdaCapture.java
+ */
+
+import java.util.Objects;
+
+public class LambdaCapture {
+    public static void main(String... args) {
+        new LambdaCapture().run();
+    }
+
+    void run() {
+        assertEquals("00", lambdaCapture1(0).t());
+        assertEquals("12", lambdaCapture1(1).t());
+        assertEquals("D", lambdaCapture1(2).t());
+        assertEquals("D", lambdaCapture1(3).t());
+        assertEquals("00", lambdaCapture2(0).t());
+        assertEquals("12", lambdaCapture2(1).t());
+        assertEquals("D", lambdaCapture2(2).t());
+        assertEquals("D", lambdaCapture2(3).t());
+    }
+
+    I<String> lambdaCapture1(int i) {
+        int j = i + 1;
+        I<String> r = switch (i) {
+            case 0 -> () -> "0" + i; //capture parameter
+            case 1 -> () -> "1" + j; //capture local variable
+            default -> {
+                String k = "D";
+                yield () -> k; //capture local from the switch expr.
+            }
+        };
+
+        return r;
+    }
+
+    I<String> lambdaCapture2(int i) {
+        int j = i + 1;
+
+        return switch (i) {
+            case 0 -> () -> "0" + i; //capture parameter
+            case 1 -> () -> "1" + j; //capture local variable
+            default -> {
+                String k = "D";
+                yield () -> k; //capture local from the switch expr.
+            }
+        };
+    }
+
+    {
+        int j1 = 1;
+        I<String> r1 = switch (j1) {
+            case 1 -> () -> "1" + j1; //capture local variable
+            default -> {
+                String k = "D";
+                yield () -> k; //capture local from the switch expr.
+            }
+        };
+        assertEquals("11", r1.t());
+
+        int j2 = 2;
+        I<String> r2 = switch (j2) {
+            case 1 -> () -> "1" + j2; //capture local variable
+            default -> {
+                String k = "D";
+                yield () -> k; //capture local from the switch expr.
+            }
+        };
+        assertEquals("D", r2.t());
+    }
+
+    private void assertEquals(Object expected, Object actual) {
+        if (!Objects.equals(expected, actual)) {
+            throw new AssertionError("Unexpected value: " + actual);
+        }
+    }
+
+    interface I<T> {
+        public T t();
+    }
+}