8309336: Incorrect switch in enum not reported properly

Reviewed-by: vromero

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

@@ -1657,9 +1657,9 @@ private void handleSwitch(JCTree switchTree,
             boolean enumSwitch = (seltype.tsym.flags() & Flags.ENUM) != 0;
             boolean stringSwitch = types.isSameType(seltype, syms.stringType);
             boolean errorEnumSwitch = TreeInfo.isErrorEnumSwitch(selector, cases);
+            boolean intSwitch = types.isAssignable(seltype, syms.intType);
             boolean patternSwitch;
-            if (!enumSwitch && !stringSwitch && !errorEnumSwitch &&
-                !types.isAssignable(seltype, syms.intType)) {
+            if (!enumSwitch && !stringSwitch && !errorEnumSwitch && !intSwitch) {
                 preview.checkSourceLevel(selector.pos(), Feature.PATTERN_SWITCH);
                 patternSwitch = true;
             } else {
@@ -1706,6 +1706,10 @@ private void handleSwitch(JCTree switchTree,
                             if (sym == null) {
                                 if (allowPatternSwitch) {
                                     attribTree(expr, switchEnv, caseLabelResultInfo(seltype));
+                                    Symbol enumSym = TreeInfo.symbol(expr);
+                                    if (enumSym == null || !enumSym.isEnum() || enumSym.kind != VAR) {
+                                        log.error(expr.pos(), Errors.EnumLabelMustBeEnumConstant);
+                                    }
                                 } else {
                                     log.error(expr.pos(), Errors.EnumLabelMustBeUnqualifiedEnum);
                                 }
@@ -1728,14 +1732,16 @@ private void handleSwitch(JCTree switchTree,
                             if (!pattype.hasTag(ERROR)) {
                                 if (pattype.constValue() == null) {
                                     Symbol s = TreeInfo.symbol(expr);
-                                    if (s != null && s.kind == TYP && allowPatternSwitch) {
+                                    if (s != null && s.kind == TYP) {
                                         log.error(expr.pos(),
                                                   Errors.PatternExpected);
-                                    } else if ((s != null && !s.isEnum()) || !allowPatternSwitch) {
+                                    } else if (s == null || !s.isEnum()) {
                                         log.error(expr.pos(),
-                                                  (stringSwitch ? Errors.StringConstReq : Errors.ConstExprReq));
+                                                  (stringSwitch ? Errors.StringConstReq
+                                                                : intSwitch ? Errors.ConstExprReq
+                                                                            : Errors.PatternOrEnumReq));
                                     }
-                                } else if (!stringSwitch && !types.isAssignable(seltype, syms.intType)) {
+                                } else if (!stringSwitch && !intSwitch) {
                                     log.error(label.pos(), Errors.ConstantLabelNotCompatible(pattype, seltype));
                                 } else if (!constants.add(pattype.constValue())) {
                                     log.error(c.pos(), Errors.DuplicateCaseLabel);

src/jdk.compiler/share/classes/com/sun/tools/javac/resources/compiler.properties

@@ -411,6 +411,9 @@ compiler.err.class.not.allowed=\
 compiler.err.const.expr.req=\
     constant expression required
 
+compiler.err.pattern.or.enum.req=\
+    pattern or enum constant required
+
 compiler.err.cont.outside.loop=\
     continue outside of loop
 
@@ -576,6 +579,9 @@ compiler.err.enum.cant.be.instantiated=\
 compiler.err.enum.label.must.be.unqualified.enum=\
     an enum switch case label must be the unqualified name of an enumeration constant
 
+compiler.err.enum.label.must.be.enum.constant=\
+    an enum switch constant case label must be an enumeration constant
+
 compiler.err.enum.no.subclassing=\
     classes cannot directly extend java.lang.Enum
 

test/langtools/tools/javac/diags/examples/EnumLabelMustBeEnumConstant.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2023, 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.
+ */
+
+// key: compiler.err.enum.label.must.be.enum.constant
+
+class EnumLabelMustBeEnumConstant {
+    enum E { A };
+
+    void m(E e) {
+        switch (e) {
+            case EA -> {}
+            default -> {}
+        }
+    }
+
+    static final E EA;
+}

test/langtools/tools/javac/diags/examples/PatternOrEnumReq.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2023, 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.
+ */
+
+// key: compiler.err.pattern.or.enum.req
+
+class PatternOrEnumReq {
+    enum E { A };
+
+    void m(Object o) {
+        switch (o) {
+            case EA -> {}
+            default -> {}
+        }
+    }
+
+    static final E EA;
+}

test/langtools/tools/javac/patterns/PatternErrorRecovery-old.out

@@ -1,3 +1,3 @@
 PatternErrorRecovery.java:12:18: compiler.err.feature.not.supported.in.source.plural: (compiler.misc.feature.pattern.switch), 20, 21
-PatternErrorRecovery.java:11:18: compiler.err.const.expr.req
+PatternErrorRecovery.java:11:18: compiler.err.pattern.expected
 2 errors

test/langtools/tools/javac/switchextra/EnumSwitchQualifiedErrors.java

@@ -23,7 +23,7 @@
 
 /**
  * @test
- * @bug 8300543
+ * @bug 8300543 8309336
  * @summary Check switches work correctly with qualified enum constants
  * @compile/fail/ref=EnumSwitchQualifiedErrors.out -XDrawDiagnostics EnumSwitchQualifiedErrors.java
 */
@@ -51,8 +51,27 @@ int testPatternMatchingSwitch3(Number n) {
         };
     }
 
+    int testPatternMatchingSwitch4(E1 e) {
+        return switch(e) {
+            case E1A -> 1;
+            case (E1) null -> 1;
+            case E1 -> 1;
+            default -> {}
+        };
+    }
+
+    int testPatternMatchingSwitch5(Object e) {
+        return switch(e) {
+            case E1A -> 1;
+            case (E1) null -> 1;
+            case E1 -> 1;
+            default -> {}
+        };
+    }
+
     sealed interface I {}
     enum E1 implements I { A; }
     enum E2 { A; }
 
+    static final E1 E1A = null;
 }

test/langtools/tools/javac/switchextra/EnumSwitchQualifiedErrors.out

@@ -2,4 +2,10 @@ EnumSwitchQualifiedErrors.java:36:20: compiler.err.prob.found.req: (compiler.mis
 EnumSwitchQualifiedErrors.java:43:20: compiler.err.prob.found.req: (compiler.misc.inconvertible.types: EnumSwitchQualifiedErrors.E2, EnumSwitchQualifiedErrors.E1)
 EnumSwitchQualifiedErrors.java:49:20: compiler.err.prob.found.req: (compiler.misc.inconvertible.types: EnumSwitchQualifiedErrors.E1, java.lang.Number)
 EnumSwitchQualifiedErrors.java:50:20: compiler.err.prob.found.req: (compiler.misc.inconvertible.types: EnumSwitchQualifiedErrors.E2, java.lang.Number)
-4 errors
+EnumSwitchQualifiedErrors.java:56:18: compiler.err.enum.label.must.be.enum.constant
+EnumSwitchQualifiedErrors.java:57:18: compiler.err.enum.label.must.be.enum.constant
+EnumSwitchQualifiedErrors.java:58:18: compiler.err.enum.label.must.be.enum.constant
+EnumSwitchQualifiedErrors.java:65:18: compiler.err.pattern.or.enum.req
+EnumSwitchQualifiedErrors.java:66:18: compiler.err.pattern.or.enum.req
+EnumSwitchQualifiedErrors.java:67:18: compiler.err.pattern.expected
+10 errors