8222850: jshell tool: Misleading cascade compiler error in switch exp…

…ression with undefined vars Reviewed-by: vromero
openjdk · Feb 3, 2021 · 9037615 · 9037615
1 parent 91e6c75
commit 9037615
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Showing 6 changed files with 63 additions and 4 deletions.
diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Attr.java
@@ -1650,6 +1650,7 @@ private void handleSwitch(JCTree switchTree,
         try {
             boolean enumSwitch = (seltype.tsym.flags() & Flags.ENUM) != 0;
             boolean stringSwitch = types.isSameType(seltype, syms.stringType);
+            boolean errorEnumSwitch = TreeInfo.isErrorEnumSwitch(selector, cases);
             if (!enumSwitch && !stringSwitch)
                 seltype = chk.checkType(selector.pos(), seltype, syms.intType);
 
@@ -1680,6 +1681,17 @@ private void handleSwitch(JCTree switchTree,
                             } else if (!labels.add(sym)) {
                                 log.error(c.pos(), Errors.DuplicateCaseLabel);
                             }
+                        } else if (errorEnumSwitch) {
+                            //error recovery: the selector is erroneous, and all the case labels
+                            //are identifiers. This could be an enum switch - don't report resolve
+                            //error for the case label:
+                            var prevResolveHelper = rs.basicLogResolveHelper;
+                            try {
+                                rs.basicLogResolveHelper = rs.silentLogResolveHelper;
+                                attribExpr(pat, switchEnv, seltype);
+                            } finally {
+                                rs.basicLogResolveHelper = prevResolveHelper;
+                            }
                         } else {
                             Type pattype = attribExpr(pat, switchEnv, seltype);
                             if (!pattype.hasTag(ERROR)) {
@@ -3796,7 +3808,7 @@ public void visitParens(JCParens tree) {
         Type owntype = attribTree(tree.expr, env, resultInfo);
         result = check(tree, owntype, pkind(), resultInfo);
         Symbol sym = TreeInfo.symbol(tree);
-        if (sym != null && sym.kind.matches(KindSelector.TYP_PCK))
+        if (sym != null && sym.kind.matches(KindSelector.TYP_PCK) && sym.kind != Kind.ERR)
             log.error(tree.pos(), Errors.IllegalParenthesizedExpression);
     }
 

diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Flow.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 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
@@ -736,7 +736,8 @@ public void visitSwitchExpression(JCSwitchExpression tree) {
                 }
                 c.completesNormally = alive != Liveness.DEAD;
             }
-            if ((constants == null || !constants.isEmpty()) && !hasDefault) {
+            if ((constants == null || !constants.isEmpty()) && !hasDefault &&
+                !TreeInfo.isErrorEnumSwitch(tree.selector, tree.cases)) {
                 log.error(tree, Errors.NotExhaustive);
             }
             alive = prevAlive;

diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Resolve.java b/src/jdk.compiler/share/classes/com/sun/tools/javac/comp/Resolve.java
@@ -2629,6 +2629,15 @@ public List<Type> getArgumentTypes(ResolveError errSym, Symbol accessedSym, Name
         }
     };
 
+    LogResolveHelper silentLogResolveHelper = new LogResolveHelper() {
+        public boolean resolveDiagnosticNeeded(Type site, List<Type> argtypes, List<Type> typeargtypes) {
+            return false;
+        }
+        public List<Type> getArgumentTypes(ResolveError errSym, Symbol accessedSym, Name name, List<Type> argtypes) {
+            return argtypes;
+        }
+    };
+
     LogResolveHelper methodLogResolveHelper = new LogResolveHelper() {
         public boolean resolveDiagnosticNeeded(Type site, List<Type> argtypes, List<Type> typeargtypes) {
             return !site.isErroneous() &&

diff --git a/src/jdk.compiler/share/classes/com/sun/tools/javac/tree/TreeInfo.java b/src/jdk.compiler/share/classes/com/sun/tools/javac/tree/TreeInfo.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 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
@@ -1324,4 +1324,9 @@ public static boolean isPackageInfo(JCCompilationUnit tree) {
         return tree.sourcefile.isNameCompatible("package-info", JavaFileObject.Kind.SOURCE);
     }
 
+    public static boolean isErrorEnumSwitch(JCExpression selector, List<JCCase> cases) {
+        return selector.type.tsym.kind == Kinds.Kind.ERR &&
+               cases.stream().flatMap(c -> c.pats.stream())
+                             .allMatch(p -> p.hasTag(IDENT));
+    }
 }
diff --git a/test/langtools/tools/javac/recovery/SwitchUndefinedSelector.java b/test/langtools/tools/javac/recovery/SwitchUndefinedSelector.java
@@ -0,0 +1,26 @@
+/**
+ * @test /nodynamiccopyright/
+ * @bug 8222850
+ * @summary Check error recovery for switch over undefined variables.
+ * @compile/fail/ref=SwitchUndefinedSelector.out -XDrawDiagnostics --should-stop=at=FLOW SwitchUndefinedSelector.java
+ */
+
+public class SwitchUndefinedSelector {
+    private static final Object D = null;
+    public void switchTest() {
+        switch (undefined) {
+            case A -> {}
+            case B, C -> {}
+            case D -> {}
+        }
+        var v = switch (undefined) {
+            case A -> 0;
+            case B, C -> 0;
+            case D -> 0;
+        };
+        switch (undefined) {
+            case SwitchUndefinedSelector.D -> {}
+            case SwitchUndefinedSelector.UNDEF -> {}
+        }
+    }
+}
diff --git a/test/langtools/tools/javac/recovery/SwitchUndefinedSelector.out b/test/langtools/tools/javac/recovery/SwitchUndefinedSelector.out
@@ -0,0 +1,6 @@
+SwitchUndefinedSelector.java:11:17: compiler.err.cant.resolve.location: kindname.variable, undefined, , , (compiler.misc.location: kindname.class, SwitchUndefinedSelector, null)
+SwitchUndefinedSelector.java:16:25: compiler.err.cant.resolve.location: kindname.variable, undefined, , , (compiler.misc.location: kindname.class, SwitchUndefinedSelector, null)
+SwitchUndefinedSelector.java:21:17: compiler.err.cant.resolve.location: kindname.variable, undefined, , , (compiler.misc.location: kindname.class, SwitchUndefinedSelector, null)
+SwitchUndefinedSelector.java:22:41: compiler.err.string.const.req
+SwitchUndefinedSelector.java:23:41: compiler.err.cant.resolve.location: kindname.variable, UNDEF, , , (compiler.misc.location: kindname.class, SwitchUndefinedSelector, null)
+5 errors