Bug 531715 - [14] JEP 305: Pattern Matching for instanceof (Preview)Y20200120-2315

Change-Id: Ia7200135c91d4a0b3d281a8b6049da03407e7d2a
Signed-off-by: Jay Arthanareeswaran <jarthana@in.ibm.com>

4 files changed, 1520 insertions, 35 deletions

diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/AbstractRegressionTest.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/AbstractRegressionTest.java
index f47faab42f..d13de86f5a 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/AbstractRegressionTest.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/AbstractRegressionTest.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2019 IBM Corporation and others.
+ * Copyright (c) 2000, 2020 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -117,10 +117,10 @@ public abstract class AbstractRegressionTest extends AbstractCompilerTest implem
 		.map(e -> e.getKey() + "=" + e.getValue())
 		.toArray(String[]::new);
 
-	protected class Runner {
+	public class Runner {
 		boolean shouldFlushOutputDirectory = true;
 		// input:
-		String[] testFiles;
+		public String[] testFiles;
 		String[] dependantFiles;
 		String[] classLibraries;
 		boolean  libsOnModulePath;
@@ -140,14 +140,14 @@ public abstract class AbstractRegressionTest extends AbstractCompilerTest implem
 		JavacTestOptions javacTestOptions;
 		// execution:
 		boolean forceExecution;
-		String[] vmArguments;
-		String expectedOutputString;
+		public String[] vmArguments;
+		public String expectedOutputString;
 		String expectedErrorString;
 
 		ASTVisitor visitor;
-
+		public Runner() {}
 		@SuppressWarnings("synthetic-access")
-		protected void runConformTest() {
+		public void runConformTest() {
 			runTest(this.shouldFlushOutputDirectory,
 					this.testFiles,
 					this.dependantFiles != null ? this.dependantFiles : new String[] {},
@@ -1872,6 +1872,11 @@ protected static class JavacTestOptions {
 				JavacTestOptions.DEFAULT /* default javac test options */,
 				charset);
 	}
+	protected void runConformTest(String[] testFiles, String expectedOutput, Map<String, String> customOptions, String[] vmArguments) {
+		runConformTest(testFiles, expectedOutput, customOptions, vmArguments, RUN_JAVAC ? /* javac test options */
+				new JavacTestOptions("-source 1.4") :
+					JavacTestOptions.DEFAULT);
+	}
 	protected void runConformTest(String[] testFiles, String expectedOutput, Map<String, String> customOptions, String[] vmArguments, JavacTestOptions javacOptions) {
 		runTest(
 			// test directory preparation
@@ -1894,28 +1899,6 @@ protected static class JavacTestOptions {
 			// javac options
 			javacOptions);
 	}
-	protected void runConformTest(String[] testFiles, String expectedOutput, Map<String, String> customOptions, String[] vmArguments) {
-		runTest(
-			// test directory preparation
-			true /* flush output directory */,
-			testFiles /* test files */,
-			// compiler options
-			null /* no class libraries */,
-			customOptions /* no custom options */,
-			false /* do not perform statements recovery */,
-			null /* no custom requestor */,
-			// compiler results
-			false /* expecting no compiler errors */,
-			null /* do not check compiler log */,
-			// runtime options
-			false /* do not force execution */,
-			vmArguments /* no vm arguments */,
-			// runtime results
-			expectedOutput /* expected output string */,
-			null /* do not check error string */,
-			// javac options
-			JavacTestOptions.DEFAULT /* default javac test options */);
-	}
 	protected void runConformTest(
 			String[] testFiles,
 			String[] dependantFiles,
@@ -2750,7 +2733,16 @@ protected void runNegativeTest(boolean skipJavac, JavacTestOptions javacTestOpti
 			String[] classLibraries,
 			boolean shouldFlushOutputDirectory,
 			Map customOptions) {
-		runNegativeTest(testFiles, expectedCompilerLog, classLibraries, shouldFlushOutputDirectory, null, customOptions);
+		runNegativeTest(testFiles, expectedCompilerLog, classLibraries, shouldFlushOutputDirectory, null, customOptions, JavacTestOptions.DEFAULT);
+	}
+	protected void runNegativeTest(
+			String[] testFiles,
+			String expectedCompilerLog,
+			String[] classLibraries,
+			boolean shouldFlushOutputDirectory,
+			String[] vmArguments,
+			Map customOptions) {
+		runNegativeTest(testFiles, expectedCompilerLog, classLibraries, shouldFlushOutputDirectory, vmArguments, customOptions, JavacTestOptions.DEFAULT);
 	}
 	protected void runNegativeTest(
 		String[] testFiles,
@@ -2758,7 +2750,8 @@ protected void runNegativeTest(boolean skipJavac, JavacTestOptions javacTestOpti
 		String[] classLibraries,
 		boolean shouldFlushOutputDirectory,
 		String[] vmArguments,
-		Map customOptions) {
+		Map customOptions,
+		JavacTestOptions javacOptions) {
 		runTest(
 	 		// test directory preparation
 			shouldFlushOutputDirectory /* should flush output directory */,
@@ -2783,7 +2776,7 @@ protected void runNegativeTest(boolean skipJavac, JavacTestOptions javacTestOpti
 			null /* do not check output string */,
 			null /* do not check error string */,
 			// javac options
-			JavacTestOptions.DEFAULT /* default javac test options */);
+			javacOptions);
 	}
 	protected void runNegativeTest(
 			boolean skipJavac,
@@ -3442,7 +3435,7 @@ protected void runNegativeTest(boolean skipJavac, JavacTestOptions javacTestOpti
 			}
 		}
 		// javac part
-		if (RUN_JAVAC && javacTestOptions != JavacTestOptions.SKIP) {
+		if (RUN_JAVAC) {
 			runJavac(testFiles, expectingCompilerErrors, expectedCompilerLog,
 					expectedJavacOutputString, expectedErrorString, shouldFlushOutputDirectory,
 					javacTestOptions, vmArguments, classLibraries, libsOnModulePath);
diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/PatternMatching14Test.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/PatternMatching14Test.java
new file mode 100644
index 0000000000..d688bfaaf0
--- /dev/null
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/PatternMatching14Test.java
@@ -0,0 +1,1491 @@
+/*******************************************************************************
+ * Copyright (c) 2020 IBM Corporation and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * This is an implementation of an early-draft specification developed under the Java
+ * Community Process (JCP) and is made available for testing and evaluation purposes
+ * only. The code is not compatible with any specification of the JCP.
+ *
+ * Contributors:
+ *     IBM Corporation - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.jdt.core.tests.compiler.regression;
+
+import java.util.Map;
+
+import org.eclipse.jdt.internal.compiler.impl.CompilerOptions;
+
+import junit.framework.Test;
+
+public class PatternMatching14Test extends AbstractRegressionTest {
+
+	private static final JavacTestOptions JAVAC_OPTIONS = new JavacTestOptions("-source 14 --enable-preview");
+	static {
+//		TESTS_NUMBERS = new int [] { 40 };
+//		TESTS_RANGE = new int[] { 1, -1 };
+//		TESTS_NAMES = new String[] { "test022" };
+	}
+	
+	public static Class<?> testClass() {
+		return PatternMatching14Test.class;
+	}
+	public static Test suite() {
+		return buildMinimalComplianceTestSuite(testClass(), F_14);
+	}
+	public PatternMatching14Test(String testName){
+		super(testName);
+	}
+	// Enables the tests to run individually
+	protected Map<String, String> getCompilerOptions(boolean preview) {
+		Map<String, String> defaultOptions = super.getCompilerOptions();
+		defaultOptions.put(CompilerOptions.OPTION_Compliance, CompilerOptions.VERSION_14);
+		defaultOptions.put(CompilerOptions.OPTION_Source, CompilerOptions.VERSION_14);
+		defaultOptions.put(CompilerOptions.OPTION_TargetPlatform, CompilerOptions.VERSION_14);
+		defaultOptions.put(CompilerOptions.OPTION_EnablePreviews,
+				preview ? CompilerOptions.ENABLED : CompilerOptions.DISABLED);
+		defaultOptions.put(CompilerOptions.OPTION_ReportPreviewFeatures, CompilerOptions.WARNING);
+		return defaultOptions;
+	}
+
+	@Override
+	protected void runConformTest(String[] testFiles, String expectedOutput, Map<String, String> customOptions) {
+		runConformTest(testFiles, expectedOutput, customOptions, new String[] {"--enable-preview"}, JAVAC_OPTIONS);
+	}
+	protected void runNegativeTest(
+			String[] testFiles,
+			String expectedCompilerLog,
+			String javacLog,
+			String[] classLibraries,
+			boolean shouldFlushOutputDirectory,
+			Map<String, String> customOptions) {
+		Runner runner = new Runner();
+		runner.testFiles = testFiles;
+		runner.expectedCompilerLog = expectedCompilerLog;
+		runner.javacTestOptions = JAVAC_OPTIONS;
+		runner.customOptions = customOptions;
+		runner.expectedJavacOutputString = javacLog;
+		runner.runNegativeTest();
+	}
+	public void test001() {
+		Map<String, String> options = getCompilerOptions(false);
+		runNegativeTest(
+				new String[] {
+						"X1.java",
+						"public class X1 {\n" +
+						"  public void foo(Object obj) {\n" +
+						"		if (obj instanceof String s) {\n" +
+						"		}\n " +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X1.java (at line 3)\n" + 
+				"	if (obj instanceof String s) {\n" + 
+				"	                   ^^^^^^^^\n" + 
+				"Instanceof Pattern is a preview feature and disabled by default. Use --enable-preview to enable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test002() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X2.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X2 {\n" +
+						"  public void foo(Integer obj) {\n" +
+						"		if (obj instanceof String s) {\n" +
+						"		}\n " +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X2.java (at line 4)\n" + 
+				"	if (obj instanceof String s) {\n" + 
+				"	    ^^^^^^^^^^^^^^^^^^^^^^^\n" + 
+				"Incompatible conditional operand types Integer and String\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test003() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X3.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X3 {\n" +
+						"  public void foo(Number num) {\n" +
+						"		if (num instanceof Integer s) {\n" +
+						"		} else if (num instanceof String) {\n" +
+						"		}\n " +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X3.java (at line 5)\n" + 
+				"	} else if (num instanceof String) {\n" + 
+				"	           ^^^^^^^^^^^^^^^^^^^^^\n" + 
+				"Incompatible conditional operand types Number and String\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test004() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X4.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X4 {\n" +
+						"  public void foo(Object obj) {\n" +
+						"		String s = null;\n" +
+						"		if (obj instanceof Integer s) {\n" +
+						"		} else if (obj instanceof String) {\n" +
+						"		}\n " +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X4.java (at line 5)\n" + 
+				"	if (obj instanceof Integer s) {\n" + 
+				"	                           ^\n" + 
+				"Duplicate local variable s\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test005() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X5.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X5 {\n" +
+						"@SuppressWarnings(\"preview\")\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		if (obj instanceof Integer i) {\n" +
+						"			System.out.print(i);\n" +
+						"		} else if (obj instanceof String s) {\n" +
+						"			System.out.print(s);\n" +
+						"		}\n " +
+						"	}\n" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(100);\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"100",
+				options);
+	}
+	public void test006() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X6.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X6 {\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		if (obj instanceof Integer i) {\n" +
+						"			System.out.print(i);\n" +
+						"		} else if (obj instanceof String s) {\n" +
+						"			System.out.print(s);\n" +
+						"		}\n " +
+						"	}\n" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"abcd",
+				options);
+	}
+	public void test006a() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X6a.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X6a {\n" +
+						"	public static void foo(Object obj) {\n" +
+						"		if (obj != null) {\n" +
+						"			if (obj instanceof Integer i) {\n" +
+						"				System.out.print(i);\n" +
+						"			} else if (obj instanceof String s) {\n" +
+						"				System.out.print(i);\n" +
+						"			}\n " +
+						"		}\n " +
+						"		System.out.print(i);\n" +
+						"	}\n" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X6a.java (at line 8)\n" + 
+				"	System.out.print(i);\n" + 
+				"	                 ^\n" + 
+				"i cannot be resolved to a variable\n" + 
+				"----------\n" + 
+				"2. ERROR in X6a.java (at line 11)\n" + 
+				"	System.out.print(i);\n" + 
+				"	                 ^\n" + 
+				"i cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test006b() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X6b.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X6b {\n" +
+						"	public static void foo(Object obj) {\n" +
+						"		if (obj != null) {\n" +
+						"			if (obj instanceof Integer i) {\n" +
+						"				System.out.print(i);\n" +
+						"			} else if (obj instanceof String s) {\n" +
+						"				System.out.print(i);\n" +
+						"			}\n " +
+						"		}\n " +
+						"		System.out.print(s);\n" +
+						"	}\n" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X6b.java (at line 8)\n" + 
+				"	System.out.print(i);\n" + 
+				"	                 ^\n" + 
+				"i cannot be resolved to a variable\n" + 
+				"----------\n" + 
+				"2. ERROR in X6b.java (at line 11)\n" + 
+				"	System.out.print(s);\n" + 
+				"	                 ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test006c() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X6c.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X6c {\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		if (obj instanceof Integer i) {\n" +
+						"			System.out.print(i);\n" +
+						"		} else if (obj instanceof String s) {\n" +
+						"			System.out.print(i);\n" +
+						"		}\n " +
+						"	}\n" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X6c.java (at line 7)\n" + 
+				"	System.out.print(i);\n" + 
+				"	                 ^\n" + 
+				"i cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test006d() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X6d.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X6d {\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		if (obj instanceof Integer i) {\n" +
+						"			System.out.print(i);\n" +
+						"		} else {\n" +
+						"			System.out.print(i);\n" +
+						"		}\n " +
+						"	}\n" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X6d.java (at line 7)\n" + 
+				"	System.out.print(i);\n" + 
+				"	                 ^\n" + 
+				"i cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test007() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X7.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X7 {\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		if (obj instanceof Integer i) {\n" +
+						"			System.out.print(i);\n" +
+						"		} else if (obj instanceof String s) {\n" +
+						"			System.out.print(i);\n" +
+						"		}\n " +
+						"	}\n" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X7.java (at line 7)\n" + 
+				"	System.out.print(i);\n" + 
+				"	                 ^\n" + 
+				"i cannot be resolved to a variable\n" + 
+				"----------\n",
+				"X7.java:4: warning: [preview] pattern matching in instanceof is a preview feature and may be removed in a future release.\n" + 
+				"		if (obj instanceof Integer i) {\n" + 
+				"		                           ^\n" + 
+				"X7.java:6: warning: [preview] pattern matching in instanceof is a preview feature and may be removed in a future release.\n" + 
+				"		} else if (obj instanceof String s) {\n" + 
+				"		                                 ^\n" + 
+				"X7.java:7: error: cannot find symbol\n" + 
+				"			System.out.print(i);\n" + 
+				"			                 ^\n" + 
+				"  symbol:   variable i\n" + 
+				"  location: class X7\n" + 
+				"1 error\n" + 
+				"2 warnings",
+				null,
+				true,
+				options);
+	}
+	public void test008() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X8.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X8 {\n" +
+						"  	public static void foo(Object b) {\n" + 
+						"		Object c = null;\n" + 
+						"		if (b != c) {\n" + 
+						"			if ((b instanceof String s) && (s.length() != 0))\n" + 
+						"				System.out.println(\"s:\" + s);\n" + 
+						"			else \n" + 
+						"				System.out.println(\"b:\" + b);\n" + 
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(100);\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"b:100\n" + 
+				"s:abcd",
+				options);
+	}
+	public void test009() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X9.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X9 {\n" +
+						"  	public static void foo(Object b) {\n" + 
+						"		Object c = null;\n" + 
+						"		if (b != c) {\n" + 
+						"			if ((b instanceof String s) && (s.length() != 0))\n" + 
+						"				System.out.println(\"s:\" + s);\n" + 
+						"			else if ((b instanceof Integer i2))\n" + 
+						"				System.out.println(\"i2:\" + i2);\n" + 
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(100);\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"i2:100\n" + 
+				"s:abcd",
+				options);
+	}
+	public void test010() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X10.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X10 {\n" +
+						"  	public static void foo(Object b) {\n" + 
+						"		Object c = null;\n" + 
+						"		if (b != c) {\n" + 
+						"			if (b != null && (b instanceof String s))\n" + 
+						"				System.out.println(\"s:\" + s);\n" + 
+						"			else " + 
+						"				System.out.println(\"b:\" + b);\n" + 
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(100);\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"b:100\n" + 
+				"s:abcd",
+				options);
+	}
+	public void test011() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X11.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X11 {\n" +
+						"  	public static void foo(Object b) {\n" + 
+						"		Object c = null;\n" + 
+						"		if (b == null && (b instanceof String s)) {\n" + 
+						"		} else {" + 
+						"		}\n" + 
+						"		System.out.println(s);\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(100);\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X11.java (at line 7)\n" + 
+				"	System.out.println(s);\n" + 
+				"	                   ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test012() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X12.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X12 {\n" +
+						"  	public static void foo(Object b) {\n" + 
+						"		Object c = null;\n" + 
+						"		if (b != c) {\n" + 
+						"			if (b == null && (b instanceof String s)) {\n" + 
+						"				System.out.println(\"s:\" + s);\n" + 
+						"			} else { " + 
+						"				System.out.println(\"b:\" + b);\n" + 
+						"			}\n" + 
+						"			s = null;\n" +
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(100);\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X12.java (at line 10)\n" + 
+				"	s = null;\n" + 
+				"	^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test013() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X13.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X13 {\n" +
+						"  	public static void foo(Object b) {\n" + 
+						"		Object c = null;\n" + 
+						"		if (b != c) {\n" + 
+						"			if (b == null && (b instanceof String s))\n" + 
+						"				System.out.println(\"s:\" + s);\n" + 
+						"			else " + 
+						"				System.out.println(\"b:\" + b);\n" + 
+						"			System.out.println(s);\n" +
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(100);\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X13.java (at line 9)\n" + 
+				"	System.out.println(s);\n" + 
+				"	                   ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test014() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X14.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X14 {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		if (!(o instanceof String s)) {\n" + 
+						"			System.out.print(\"then:\" + s);\n" +
+						"		} else {\n" +
+						"			System.out.print(\"else:\" + s);\n" +
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X14.java (at line 5)\n" + 
+				"	System.out.print(\"then:\" + s);\n" + 
+				"	                           ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test014a() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X14.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X14 {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		if (!(o instanceof String s)) {\n" + 
+						"			System.out.print(\"then:\" + s);\n" +
+						"		} else {\n" +
+						"			System.out.print(\"else:\" + s);\n" +
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X14.java (at line 5)\n" + 
+				"	System.out.print(\"then:\" + s);\n" + 
+				"	                           ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test014b() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X14.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X14 {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		if (!!(o instanceof String s)) {\n" + 
+						"			System.out.print(\"then:\" + s);\n" +
+						"		} else {\n" +
+						"			System.out.print(\"else:\" + s);\n" +
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X14.java (at line 7)\n" + 
+				"	System.out.print(\"else:\" + s);\n" + 
+				"	                           ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test014c() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X14.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X14 {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		if (o == null) {\n" + 
+						"			System.out.print(\"null\");\n" +
+						"		} else if(!(o instanceof String s)) {\n" +
+						"			System.out.print(\"else:\" + s);\n" +
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X14.java (at line 7)\n" + 
+				"	System.out.print(\"else:\" + s);\n" + 
+				"	                           ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test014d() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X14.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X14 {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		if (o == null) {\n" + 
+						"			System.out.print(\"null\");\n" +
+						"		} else if(!!(o instanceof String s)) {\n" +
+						"			System.out.print(\"else:\" + s);\n" +
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"else:abcd",
+				options);
+	}
+	public void test014e() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X14a.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X14a {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		 if (!(!(o instanceof String s))) {\n" + 
+						"			System.out.print(\"s:\" + s);\n" +
+						"		} else {\n" + 
+						"		}\n" + 
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"s:abcd",
+				options);
+	}
+	/*
+	 * Test that when pattern tests for false and if doesn't complete
+	 * normally, then the variable is available beyond the if statement
+	 */
+	public void test015() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X15.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X15 {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		if (!(o instanceof String s)) {\n" + 
+						"			throw new IllegalArgumentException();\n" +
+						"		} else {\n" + 
+						"			System.out.print(\"s:\" + s);\n" + 
+						"		}\n" + 
+						"		System.out.print(s);\n" +
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"s:abcdabcd",
+				options);
+	}
+	/*
+	 * Test that when pattern tests for false and if doesn't complete
+	 * normally, then the variable is available beyond the if statement
+	 */
+	public void test015a() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X15a.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X15a {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		if (!(o instanceof String s)) {\n" + 
+						"			throw new IllegalArgumentException();\n" +
+						"		}\n" + 
+						"		System.out.print(s);\n" +
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"abcd",
+				options);
+	}
+	/*
+	 * Test that when pattern tests for false and if completes
+	 * normally, then the variable is not available beyond the if statement
+	 */
+	public void test015b() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X15b.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X15b {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		if (!(o instanceof String s)) {\n" + 
+						"			//throw new IllegalArgumentException();\n" +
+						"		} else {\n" + 
+						"			System.out.print(\"s:\" + s);\n" + 
+						"		}\n" + 
+						"		System.out.print(s);\n" +
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(\"abcd\");\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X15b.java (at line 9)\n" + 
+				"	System.out.print(s);\n" + 
+				"	                 ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test016() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X16.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X16 {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		boolean b = (o instanceof String[] s && s.length == 1);\n" + 
+						"		System.out.print(b);\n" +
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(new String[]{\"one\"});\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"true",
+				options);
+	}
+	public void test017() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X17.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X17 {\n" +
+						"  	public static void foo(Object o) {\n" + 
+						"		boolean b = (o instanceof String[] s && s.length == 1);\n" + 
+						"		System.out.print(s[0]);\n" +
+						"	}" +
+						"  public static void main(String[] obj) {\n" +
+						"		foo(new String[]{\"one\"});\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X17.java (at line 5)\n" + 
+				"	System.out.print(s[0]);\n" + 
+				"	                 ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	/* Test that the scopes of pattern variable in a block doesn't affect
+	 * another outside but declared after the block
+	 */
+	public void test018() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X18.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X18 {\n" +
+						"  public static void main(String[] obj) {\n" +
+						"		boolean a = true;\n" +
+						"		{\n" + 
+						"			boolean b = (obj instanceof String[] s && s.length == 0);\n" + 
+						"			System.out.print(b + \",\");\n" + 
+						"		}\n" + 
+						"		boolean b = a ? false : (obj instanceof String[] s && s.length == 0);\n" + 
+						"		System.out.print(b);\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"true,false",
+				options);
+	}
+	/* Test that the scopes of pattern variable in a block doesn't affect
+	 * another outside but declared before the block
+	 */
+	public void test019() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X19.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X19 {\n" +
+						"  public static void main(String[] obj) {\n" +
+						"		boolean a = true;\n" +
+						"		boolean b = a ? false : (obj instanceof String[] s && s.length == 0);\n" + 
+						"		System.out.print(b + \",\");\n" +
+						"		{\n" + 
+						"			b = (obj instanceof String[] s && s.length == 0);\n" + 
+						"			System.out.print(b);\n" + 
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"false,true",
+				options);
+	}
+	/* Test that we allow consequent pattern expressions in the same statement
+	 */
+	public void test020() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X20.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X20 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		boolean b = (o instanceof String[] s) && s instanceof String[] s2;\n" + 
+						"		System.out.print(b);\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"true",
+				options);
+	}
+	/* Test that we allow consequent pattern expressions in the same statement
+	 */
+	public void test021() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X21.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X21 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		boolean b = (o instanceof String[] s) && s instanceof String[] s2;\n" + 
+						"		System.out.print(s);\n" +
+						"		System.out.print(s2);\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X21.java (at line 5)\n" + 
+				"	System.out.print(s);\n" + 
+				"	                 ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n" + 
+				"2. ERROR in X21.java (at line 6)\n" + 
+				"	System.out.print(s2);\n" + 
+				"	                 ^^\n" + 
+				"s2 cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	/* Test that we allow pattern expressions in a while statement
+	 */
+	public void test022() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X22.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X22 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object o) {\n" +
+						"		while ((o instanceof String s) && s.length() > 0) {\n" + 
+						"			o = s.substring(0, s.length() - 1);\n" +
+						"			System.out.println(s);\n" +
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"one\non\no",
+				options);
+	}
+	/* Test pattern expressions in a while statement with break
+	 */
+	public void test023() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X23.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X23 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object o) {\n" +
+						"		while (!(o instanceof String s) && s.length() > 0) {\n" + 
+						"			System.out.println(s);\n" +
+						"			break;\n" +
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X23.java (at line 7)\n" + 
+				"	while (!(o instanceof String s) && s.length() > 0) {\n" + 
+				"	                                   ^\n" + 
+				"s cannot be resolved\n" + 
+				"----------\n" + 
+				"2. ERROR in X23.java (at line 8)\n" + 
+				"	System.out.println(s);\n" + 
+				"	                   ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	/* Test pattern expressions in a while statement with no break
+	 */
+	public void test023a() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X23.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X23 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object o) {\n" +
+						"		while (!(o instanceof String s) && s.length() > 0) {\n" + 
+						"			System.out.println(s);\n" +
+						"			//break;\n" +
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X23.java (at line 7)\n" + 
+				"	while (!(o instanceof String s) && s.length() > 0) {\n" + 
+				"	                                   ^\n" + 
+				"s cannot be resolved\n" + 
+				"----------\n" + 
+				"2. ERROR in X23.java (at line 8)\n" + 
+				"	System.out.println(s);\n" + 
+				"	                   ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test024a() {
+		Map<String, String> options = getCompilerOptions(true);
+		runConformTest(
+				new String[] {
+						"X24a.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X24a {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object o) {\n" +
+						"		while (!(o instanceof String s)) {\n" + 
+						"			throw new IllegalArgumentException();\n" +
+						"		}\n" + 
+						"		System.out.println(s);\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"one",
+				options);
+	}
+	/* Test that we reject two patter variables with same name in the same
+	 * equals expression
+	 */
+	public void test025() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X25.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X25 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\", \"two\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object o, Object p) {\n" +
+						"		if ((o instanceof String s) != p instanceof String s) {\n" + 
+						"			System.out.print(\"s:\" + s);\n" +
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X25.java (at line 7)\n" + 
+				"	if ((o instanceof String s) != p instanceof String s) {\n" + 
+				"	                                                   ^\n" + 
+				"Duplicate local variable s\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	/* Test that we reject two patter variables with same name in the same
+	 * equals expression
+	 */
+	public void test026() {
+		Map<String, String> options = getCompilerOptions(true);
+		runNegativeTest(
+				new String[] {
+						"X26.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X26 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\", \"two\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object o, Object p) {\n" +
+						"		if ((o instanceof String s) == p instanceof String s) {\n" + 
+						"			System.out.print(\"s:\" + s);\n" +
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X26.java (at line 7)\n" + 
+				"	if ((o instanceof String s) == p instanceof String s) {\n" + 
+				"	                                                   ^\n" + 
+				"Duplicate local variable s\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				options);
+	}
+	public void test027() {
+		runConformTest(
+				new String[] {
+						"X27.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X27 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		for(int i = 0; (obj instanceof String[] s && s.length > 0 && i < s.length); i++) {\n" + 
+						"			System.out.println(s[i]);\n" +
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"",
+				getCompilerOptions(true));
+	}
+	public void test028() {
+		runConformTest(
+				new String[] {
+						"X28.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X28 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(new String[] {\"one\", \"two\"});\n" + 
+						"	}\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		for(int i = 0; (obj instanceof String[] s && s.length > 0 && i < s.length); i++) {\n" + 
+						"			System.out.println(s[i]);\n" +
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"one\ntwo",
+				getCompilerOptions(true));
+	}
+	public void test029() {
+		runConformTest(
+				new String[] {
+						"X29.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X29 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(new String[] {\"one\", \"two\"});\n" + 
+						"	}\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		for(int i = 0; (obj instanceof String[] s) && s.length > 0 && i < s.length; i = (s != null ? i + 1 : i)) {\n" + 
+						"			System.out.println(s[i]);\n" +
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"one\ntwo",
+				getCompilerOptions(true));
+	}
+	/*
+	 * Test that pattern variables are accepted in initialization of
+	 * a for statement
+	 * TODO: Javac rejects this
+	 */
+	public void test030() {
+		runConformTest(
+				new String[] {
+						"X30.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X30 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		for(int i = 0, length = (obj instanceof String s) ? s.length() : 0; i < length; i++) {\n" + 
+						"			System.out.print(s.charAt(i));\n" +
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"one",
+				getCompilerOptions(true));
+	}
+	public void test031() {
+		runNegativeTest(
+				new String[] {
+						"X31.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X31 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		for(int i = 0; !(obj instanceof String[] s) && s.length > 0 && i < s.length; i++) {\n" + 
+						"			System.out.println(s[i]);\n" +
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X31.java (at line 7)\n" + 
+				"	for(int i = 0; !(obj instanceof String[] s) && s.length > 0 && i < s.length; i++) {\n" + 
+				"	                                               ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n" + 
+				"2. ERROR in X31.java (at line 7)\n" + 
+				"	for(int i = 0; !(obj instanceof String[] s) && s.length > 0 && i < s.length; i++) {\n" + 
+				"	                                                                   ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n" + 
+				"3. ERROR in X31.java (at line 8)\n" + 
+				"	System.out.println(s[i]);\n" + 
+				"	                   ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				getCompilerOptions(true));
+	}
+	public void test032() {
+		runConformTest(
+				new String[] {
+						"X32.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X32 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		String res = null;\n" + 
+						"		int i = 0;\n" + 
+						"		switch(i) {\n" + 
+						"		case 0:\n" + 
+						"			res = (obj instanceof String s) ? s : null;\n" + 
+						"		default:\n" + 
+						"			break;\n" + 
+						"		}\n" + 
+						"		System.out.println(res);\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"one",
+				getCompilerOptions(true));
+	}
+	/*
+	 * FAILURE: Javac rejects this code, but we accept.
+	 */
+	public void test033() {
+		runConformTest(
+				new String[] {
+						"X33.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X33 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		String res = null;\n" + 
+						"		int i = 0;\n" + 
+						"		switch(i) {\n" + 
+						"		case 0:\n" + 
+						"			res = (obj instanceof String s) ? s : null;\n" + 
+						"			res = s.substring(1);\n" + 
+						"		default:\n" + 
+						"			break;\n" + 
+						"		}\n" + 
+						"		System.out.println(res);\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"ne",
+				getCompilerOptions(true));
+	}
+	public void test034() {
+		runNegativeTest(
+				new String[] {
+						"X34.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X34 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		int i = 0;\n" + 
+						"		String result = switch(i) {\n" + 
+						"			case 0 -> {\n" + 
+						"				result = (obj instanceof String s) ? s : null;\n" + 
+						"				yield result;\n" + 
+						"			}\n" + 
+						"			default -> {\n" + 
+						"				yield result;\n" + 
+						"			}\n" + 
+						"		};\n" + 
+						"		System.out.println(result);\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X34.java (at line 14)\n" + 
+				"	yield result;\n" + 
+				"	      ^^^^^^\n" + 
+				"The local variable result may not have been initialized\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				getCompilerOptions(true));
+	}
+	public void test035() {
+		runNegativeTest(
+				new String[] {
+						"X35.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X35 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		int i = 0;\n" + 
+						"		String result = switch(i) {\n" + 
+						"			case 0 -> {\n" + 
+						"				result = (obj instanceof String s) ? s : null;\n" + 
+						"				yield s;\n" + 
+						"			}\n" + 
+						"			default -> {\n" + 
+						"				yield s;\n" + 
+						"			}\n" + 
+						"		};\n" + 
+						"		System.out.println(result);\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X35.java (at line 11)\n" + 
+				"	yield s;\n" + 
+				"	      ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n" + 
+				"2. ERROR in X35.java (at line 14)\n" + 
+				"	yield s;\n" + 
+				"	      ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				"",
+				null,
+				true,
+				getCompilerOptions(true));
+	}
+	public void test036() {
+		runConformTest(
+				new String[] {
+						"X36.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X36 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(\"one\");\n" + 
+						"	}\n" +
+						"  public static void foo(Object obj) {\n" +
+						"		int i = 0;\n" + 
+						"		String result = switch(i) {\n" + 
+						"			default -> {\n" + 
+						"				result = (obj instanceof String s) ? s : null;\n" + 
+						"				yield result;\n" + 
+						"			}\n" + 
+						"		};\n" + 
+						"		System.out.println(result);\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"one",
+				getCompilerOptions(true));
+	}
+	public void test037() {
+		runNegativeTest(
+				new String[] {
+						"X37.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X37 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(new String[] {\"abcd\"});\n" + 
+						"	}\n" +
+						"  public static void foo(Object[] obj) {\n" +
+						"		for(int i = 0; (obj[i] instanceof String s) && s.length() > 0 ; i++) {\n" + 
+						"			System.out.println(s[i]);\n" + 
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X37.java (at line 8)\n" + 
+				"	System.out.println(s[i]);\n" + 
+				"	                   ^^^^\n" + 
+				"The type of the expression must be an array type but it resolved to String\n" + 
+				"----------\n",
+				null,
+				true,
+				getCompilerOptions(true));
+	}
+	public void test038() {
+		runNegativeTest(
+				new String[] {
+						"X38.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X38 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(new String[] {\"abcd\"});\n" + 
+						"	}\n" +
+						"  public static void foo(Object[] obj) {\n" +
+						"		for(int i = 0; (obj[i] instanceof String s) && s.length() > 0 ; i++) {\n" + 
+						"			throw new IllegalArgumentException();\n" + 
+						"		}\n" + 
+						"		System.out.println(s);\n" +
+						"	}\n" +
+						"}\n",
+				},
+				"----------\n" + 
+				"1. ERROR in X38.java (at line 10)\n" + 
+				"	System.out.println(s);\n" + 
+				"	                   ^\n" + 
+				"s cannot be resolved to a variable\n" + 
+				"----------\n",
+				null,
+				true,
+				getCompilerOptions(true));
+	}
+	/*
+	 * Failing with VerifyError
+	 */
+	public void _test039() {
+		runConformTest(
+				new String[] {
+						"X39.java",
+						"@SuppressWarnings(\"preview\")\n" +
+						"public class X39 {\n" +
+						"  public static void main(String[] o) {\n" +
+						"		foo(new String[] {\"one\"});;\n" + 
+						"	}\n" +
+						"  public static void foo(Object[] obj) {\n" +
+						"		for(int i = 0; i < obj.length && (obj[i] instanceof String s) && i < s.length(); i++) {\n" + 
+						"			System.out.println(s);\n" + 
+						"		}\n" + 
+						"	}\n" +
+						"}\n",
+				},
+				"one",
+				getCompilerOptions(true));
+	}
+}
\ No newline at end of file
diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchExpressionsYieldTest.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchExpressionsYieldTest.java
index dd34764133..ce0b2b0c61 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchExpressionsYieldTest.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/SwitchExpressionsYieldTest.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2019 IBM Corporation and others.
+ * Copyright (c) 2020 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/TestAll.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/TestAll.java
index 5af8bb7fa5..2fbef8fe60 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/TestAll.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/TestAll.java
@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2000, 2019 IBM Corporation and others.
+ * Copyright (c) 2000, 2020 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
@@ -196,6 +196,7 @@ public static Test suite() {
 	 ArrayList since_14 = new ArrayList();
 	 since_14.add(SwitchExpressionsYieldTest.class);
 	 since_14.add(RecordsRestrictedClassTest.class);
+	 since_14.add(PatternMatching14Test.class);
 
 	// Build final test suite
 	TestSuite all = new TestSuite(TestAll.class.getName());