8268663: Crash when guards contain boolean expression

Reviewed-by: vromero

Author: lahodaj

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

@@ -2392,6 +2392,10 @@ private void handleSwitch(JCTree tree, JCExpression selector,
                 JCCase c = l.head;
                 for (JCCaseLabel pat : c.labels) {
                     scan(pat);
+                    if (inits.isReset()) {
+                        inits.assign(initsWhenTrue);
+                        uninits.assign(uninitsWhenTrue);
+                    }
                 }
                 if (l.head.stats.isEmpty() &&
                     l.tail.nonEmpty() &&

test/langtools/tools/javac/patterns/Guards.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2017, 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
@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 8262891
+ * @bug 8262891 8268663
  * @summary Check guards implementation.
  * @compile --enable-preview -source ${jdk.version} Guards.java
  * @run main/othervm --enable-preview Guards
@@ -43,6 +43,9 @@ void run() {
         run(this::testBooleanSwitchExpression);
         assertEquals("a", testPatternInGuard("a"));
         assertEquals(null, testPatternInGuard(1));
+        runIfTrue(this::typeGuardIfTrueIfStatement);
+        runIfTrue(this::typeGuardIfTrueSwitchExpression);
+        runIfTrue(this::typeGuardIfTrueSwitchStatement);
     }
 
     void run(Function<Object, String> convert) {
@@ -52,6 +55,12 @@ void run(Function<Object, String> convert) {
         assertEquals("any", convert.apply(""));
     }
 
+    void runIfTrue(Function<Object, String> convert) {
+        assertEquals("true", convert.apply(0));
+        assertEquals("second", convert.apply(2));
+        assertEquals("any", convert.apply(""));
+    }
+
     String typeTestPatternSwitchTest(Object o) {
         switch (o) {
             case Integer i && i == 0: return "zero";
@@ -84,6 +93,35 @@ String testBooleanSwitchExpression(Object o) {
         }
     }
 
+    String typeGuardIfTrueSwitchStatement(Object o) {
+        Object o2 = "";
+        switch (o) {
+            case Integer i && i == 0 && i < 1 && o2 instanceof String s: o = s + String.valueOf(i); return "true";
+            case Integer i && i == 0 || i > 1: o = String.valueOf(i); return "second";
+            case Object x: return "any";
+        }
+    }
+
+    String typeGuardIfTrueSwitchExpression(Object o) {
+        Object o2 = "";
+        return switch (o) {
+            case Integer i && i == 0 && i < 1 && o2 instanceof String s: o = s + String.valueOf(i); yield "true";
+            case Integer i && i == 0 || i > 1: o = String.valueOf(i); yield "second";
+            case Object x: yield "any";
+        };
+    }
+
+    String typeGuardIfTrueIfStatement(Object o) {
+        Object o2 = "";
+        if (o != null && o instanceof (Integer i && i == 0 && i < 1) && (o = i) != null && o2 instanceof String s) {
+            return s != null ? "true" : null;
+        } else if (o != null && o instanceof (Integer i && i == 0 || i > 1) && (o = i) != null) {
+            return "second";
+        } else {
+            return "any";
+        }
+    }
+
     String testPatternInGuard(Object o) {
         if (o instanceof (CharSequence cs && cs instanceof String s)) {
             return s;

test/langtools/tools/javac/patterns/SwitchErrors.java

@@ -190,4 +190,16 @@ void sealedNonAbstract(SealedNonAbstract obj) {
     }
     sealed class SealedNonAbstract permits A {}
     final class A extends SealedNonAbstract {}
+    Object guardWithMatchingStatement(Object o1, Object o2) {
+        switch (o1) {
+            case String s && s.isEmpty() || o2 instanceof Number n: return n;
+            default: return null;
+        }
+    }
+    Object guardWithMatchingExpression(Object o1, Object o2) {
+        return switch (o1) {
+            case String s && s.isEmpty() || o2 instanceof Number n -> n;
+            default -> null;
+        };
+    }
 }

test/langtools/tools/javac/patterns/SwitchErrors.out

@@ -28,6 +28,8 @@ SwitchErrors.java:166:18: compiler.err.flows.through.from.pattern
 SwitchErrors.java:171:27: compiler.err.flows.through.to.pattern
 SwitchErrors.java:177:18: compiler.err.flows.through.to.pattern
 SwitchErrors.java:183:13: compiler.err.pattern.dominated
+SwitchErrors.java:195:76: compiler.err.cant.resolve.location: kindname.variable, n, , , (compiler.misc.location: kindname.class, SwitchErrors, null)
+SwitchErrors.java:201:71: compiler.err.cant.resolve.location: kindname.variable, n, , , (compiler.misc.location: kindname.class, SwitchErrors, null)
 SwitchErrors.java:32:9: compiler.err.not.exhaustive.statement
 SwitchErrors.java:38:9: compiler.err.not.exhaustive.statement
 SwitchErrors.java:44:9: compiler.err.not.exhaustive.statement
@@ -41,4 +43,4 @@ SwitchErrors.java:127:9: compiler.err.not.exhaustive.statement
 SwitchErrors.java:187:9: compiler.err.not.exhaustive.statement
 - compiler.note.preview.filename: SwitchErrors.java, DEFAULT
 - compiler.note.preview.recompile
-41 errors
+43 errors