8071291: Compiler crashes trying to cast UnionType to IntersectionClassType

Summary: Compiler tests for .isCompound but then cast to a more specific Type subclass, resulting in CCE
Reviewed-by: vromero, jlahoda

langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Type.java

@@ -477,6 +477,14 @@ public abstract class Type extends AnnoConstruct implements TypeMirror {
             && (tsym.flags() & COMPOUND) != 0;
     }
 
+    public boolean isIntersection() {
+        return false;
+    }
+
+    public boolean isUnion() {
+        return false;
+    }
+
     public boolean isInterface() {
         return (tsym.flags() & INTERFACE) != 0;
     }
@@ -1079,6 +1087,11 @@ public abstract class Type extends AnnoConstruct implements TypeMirror {
             return Collections.unmodifiableList(alternatives_field);
         }
 
+        @Override
+        public boolean isUnion() {
+            return true;
+        }
+
         @Override @DefinedBy(Api.LANGUAGE_MODEL)
         public TypeKind getKind() {
             return TypeKind.UNION;
@@ -1125,6 +1138,11 @@ public abstract class Type extends AnnoConstruct implements TypeMirror {
             return interfaces_field.prepend(supertype_field);
         }
 
+        @Override
+        public boolean isIntersection() {
+            return true;
+        }
+
         public List<Type> getExplicitComponents() {
             return allInterfaces ?
                     interfaces_field :

langtools/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java

@@ -1516,8 +1516,8 @@ public class Types {
                     }
                 }
 
-                if (t.isCompound() || s.isCompound()) {
-                    return !t.isCompound() ?
+                if (t.isIntersection() || s.isIntersection()) {
+                    return !t.isIntersection() ?
                             visitIntersectionType((IntersectionClassType)s, t, true) :
                             visitIntersectionType((IntersectionClassType)t, s, false);
                 }
@@ -2245,19 +2245,28 @@ public class Types {
     }
     // </editor-fold>
 
-    // <editor-fold defaultstate="collapsed" desc="makeCompoundType">
+    // <editor-fold defaultstate="collapsed" desc="makeIntersectionType">
     /**
-     * Make a compound type from non-empty list of types.  The list should be
-     * ordered according to {@link Symbol#precedes(TypeSymbol,Types)}.
+     * Make an intersection type from non-empty list of types.  The list should be ordered according to
+     * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion.
+     * Hence, this version of makeIntersectionType may not be called during a classfile read.
      *
-     * @param bounds            the types from which the compound type is formed
-     * @param supertype         is objectType if all bounds are interfaces,
-     *                          null otherwise.
+     * @param bounds    the types from which the intersection type is formed
      */
-    public Type makeCompoundType(List<Type> bounds) {
-        return makeCompoundType(bounds, bounds.head.tsym.isInterface());
+    public IntersectionClassType makeIntersectionType(List<Type> bounds) {
+        return makeIntersectionType(bounds, bounds.head.tsym.isInterface());
     }
-    public Type makeCompoundType(List<Type> bounds, boolean allInterfaces) {
+
+    /**
+     * Make an intersection type from non-empty list of types.  The list should be ordered according to
+     * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as
+     * an extra parameter indicates as to whether all bounds are interfaces - in which case the
+     * supertype is implicitly assumed to be 'Object'.
+     *
+     * @param bounds        the types from which the intersection type is formed
+     * @param allInterfaces are all bounds interface types?
+     */
+    public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) {
         Assert.check(bounds.nonEmpty());
         Type firstExplicitBound = bounds.head;
         if (allInterfaces) {
@@ -2270,23 +2279,13 @@ public class Types {
                                 : names.empty,
                             null,
                             syms.noSymbol);
-        bc.type = new IntersectionClassType(bounds, bc, allInterfaces);
+        IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
+        bc.type = intersectionType;
         bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
                 syms.objectType : // error condition, recover
                 erasure(firstExplicitBound);
         bc.members_field = WriteableScope.create(bc);
-        return bc.type;
-    }
-
-    /**
-     * A convenience wrapper for {@link #makeCompoundType(List)}; the
-     * arguments are converted to a list and passed to the other
-     * method.  Note that this might cause a symbol completion.
-     * Hence, this version of makeCompoundType may not be called
-     * during a classfile read.
-     */
-    public Type makeCompoundType(Type bound1, Type bound2) {
-        return makeCompoundType(List.of(bound1, bound2));
+        return intersectionType;
     }
     // </editor-fold>
 
@@ -2426,7 +2425,7 @@ public class Types {
         private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() {
 
             public List<Type> visitType(final Type type, final Void ignored) {
-                if (!type.isCompound()) {
+                if (!type.isIntersection()) {
                     final Type sup = supertype(type);
                     return (sup == Type.noType || sup == type || sup == null)
                         ? interfaces(type)
@@ -2480,30 +2479,32 @@ public class Types {
 
     // <editor-fold defaultstate="collapsed" desc="setBounds">
     /**
-     * Set the bounds field of the given type variable to reflect a
-     * (possibly multiple) list of bounds.
-     * @param t                 a type variable
-     * @param bounds            the bounds, must be nonempty
-     * @param supertype         is objectType if all bounds are interfaces,
-     *                          null otherwise.
+     * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly,
+     * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise
+     * the supertype is simply left null (in this case, the supertype is assumed to be the head of
+     * the bound list passed as second argument). Note that this check might cause a symbol completion.
+     * Hence, this version of setBounds may not be called during a classfile read.
+     *
+     * @param t         a type variable
+     * @param bounds    the bounds, must be nonempty
      */
     public void setBounds(TypeVar t, List<Type> bounds) {
         setBounds(t, bounds, bounds.head.tsym.isInterface());
     }
 
     /**
-     * Same as {@link #setBounds(Type.TypeVar,List,Type)}, except that
-     * third parameter is computed directly, as follows: if all
-     * all bounds are interface types, the computed supertype is Object,
-     * otherwise the supertype is simply left null (in this case, the supertype
-     * is assumed to be the head of the bound list passed as second argument).
-     * Note that this check might cause a symbol completion. Hence, this version of
-     * setBounds may not be called during a classfile read.
+     * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds.
+     * This does not cause symbol completion as an extra parameter indicates as to whether all bounds
+     * are interfaces - in which case the supertype is implicitly assumed to be 'Object'.
+     *
+     * @param t             a type variable
+     * @param bounds        the bounds, must be nonempty
+     * @param allInterfaces are all bounds interface types?
      */
     public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
         t.bound = bounds.tail.isEmpty() ?
                 bounds.head :
-                makeCompoundType(bounds, allInterfaces);
+                makeIntersectionType(bounds, allInterfaces);
         t.rank_field = -1;
     }
     // </editor-fold>
@@ -3035,7 +3036,7 @@ public class Types {
                 if (st == supertype(t) && is == interfaces(t))
                     return t;
                 else
-                    return makeCompoundType(is.prepend(st));
+                    return makeIntersectionType(is.prepend(st));
             }
         }
 
@@ -3544,7 +3545,7 @@ public class Types {
         else if (compound.tail.isEmpty())
             return compound.head;
         else
-            return makeCompoundType(compound);
+            return makeIntersectionType(compound);
     }
 
     /**
@@ -3722,8 +3723,8 @@ public class Types {
                 synchronized (this) {
                     if (arraySuperType == null) {
                         // JLS 10.8: all arrays implement Cloneable and Serializable.
-                        arraySuperType = makeCompoundType(List.of(syms.serializableType,
-                                                                  syms.cloneableType), true);
+                        arraySuperType = makeIntersectionType(List.of(syms.serializableType,
+                                syms.cloneableType), true);
                     }
                 }
             }
@@ -3789,7 +3790,7 @@ public class Types {
                     return glbFlattened(union(bounds, lowers), errT);
             }
         }
-        return makeCompoundType(bounds);
+        return makeIntersectionType(bounds);
     }
     // </editor-fold>
 

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

@@ -2355,7 +2355,7 @@ public class Attr extends JCTree.Visitor {
 
             @Override
             public Type visitClassType(ClassType t, DiagnosticPosition pos) {
-                return t.isCompound() ?
+                return t.isIntersection() ?
                         visitIntersectionClassType((IntersectionClassType)t, pos) : t;
             }
 
@@ -2386,8 +2386,7 @@ public class Attr extends JCTree.Visitor {
                     }
                     supertypes.append(i.tsym.type);
                 }
-                IntersectionClassType notionalIntf =
-                        (IntersectionClassType)types.makeCompoundType(supertypes.toList());
+                IntersectionClassType notionalIntf = types.makeIntersectionType(supertypes.toList());
                 notionalIntf.allparams_field = targs.toList();
                 notionalIntf.tsym.flags_field |= INTERFACE;
                 return notionalIntf.tsym;
@@ -3947,7 +3946,7 @@ public class Attr extends JCTree.Visitor {
         } else if (bounds.length() == 1) {
             return bounds.head.type;
         } else {
-            Type owntype = types.makeCompoundType(TreeInfo.types(bounds));
+            Type owntype = types.makeIntersectionType(TreeInfo.types(bounds));
             // ... the variable's bound is a class type flagged COMPOUND
             // (see comment for TypeVar.bound).
             // In this case, generate a class tree that represents the

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

@@ -417,7 +417,7 @@ public class Infer {
             List<Type> upperBounds = uv.getBounds(InferenceBound.UPPER);
             if (Type.containsAny(upperBounds, vars)) {
                 TypeSymbol fresh_tvar = new TypeVariableSymbol(Flags.SYNTHETIC, uv.qtype.tsym.name, null, uv.qtype.tsym.owner);
-                fresh_tvar.type = new TypeVar(fresh_tvar, types.makeCompoundType(uv.getBounds(InferenceBound.UPPER)), null);
+                fresh_tvar.type = new TypeVar(fresh_tvar, types.makeIntersectionType(uv.getBounds(InferenceBound.UPPER)), null);
                 todo.append(uv);
                 uv.inst = fresh_tvar.type;
             } else if (upperBounds.nonEmpty()) {
@@ -670,7 +670,7 @@ public class Infer {
         if (lubResult == syms.errType || lubResult == syms.botType) {
             return List.nil();
         }
-        List<Type> supertypesToCheck = lubResult.isCompound() ?
+        List<Type> supertypesToCheck = lubResult.isIntersection() ?
                 ((IntersectionClassType)lubResult).getComponents() :
                 List.of(lubResult);
         ListBuffer<Pair<Type, Type>> commonSupertypes = new ListBuffer<>();

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

@@ -764,7 +764,7 @@ public class TransTypes extends TreeTranslator {
                 ? typeCast.expr
                 : newExpression;
         }
-        if (originalTarget.isCompound()) {
+        if (originalTarget.isIntersection()) {
             Type.IntersectionClassType ict = (Type.IntersectionClassType)originalTarget;
             for (Type c : ict.getExplicitComponents()) {
                 Type ec = erasure(c);

langtools/test/tools/javac/multicatch/8071291/T8071291.java

+/*
+ * Copyright (c) 2015, 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 8071291
+ * @summary Compiler crashes trying to cast UnionType to IntersectionClassType
+ * @compile T8071291.java
+ */
+
+class T8071291 {
+
+    interface A { }
+    class Exception1 extends Exception implements A { }
+    class Exception2 extends Exception implements A { }
+
+    void test(boolean cond) {
+        try {
+            if (cond) {
+                throw new Exception1();
+            } else {
+                throw new Exception2();
+            }
+        }
+        catch (Exception1|Exception2 x) {
+            if (x instanceof Exception1) { }
+        }
+    }
+}