7015104: use new subtype of TypeSymbol for type parameters

Reviewed-by: jjg, mcimadamore

src/share/classes/com/sun/tools/javac/code/Symbol.java

@@ -496,10 +496,11 @@ public abstract class Symbol implements Element {
         return List.nil();
     }
 
-    public List<TypeSymbol> getTypeParameters() {
-        ListBuffer<TypeSymbol> l = ListBuffer.lb();
+    public List<TypeVariableSymbol> getTypeParameters() {
+        ListBuffer<TypeVariableSymbol> l = ListBuffer.lb();
         for (Type t : type.getTypeArguments()) {
-            l.append(t.tsym);
+            Assert.check(t.tsym.getKind() == ElementKind.TYPE_PARAMETER);
+            l.append((TypeVariableSymbol)t.tsym);
         }
         return l.toList();
     }
@@ -546,19 +547,12 @@ public abstract class Symbol implements Element {
         }
     }
 
-    /** A class for type symbols. Type variables are represented by instances
-     *  of this class, classes and packages by instances of subclasses.
+    /** A base class for Symbols representing types.
      */
-    public static class TypeSymbol
-            extends Symbol implements TypeParameterElement {
-        // Implements TypeParameterElement because type parameters don't
-        // have their own TypeSymbol subclass.
-        // TODO: type parameters should have their own TypeSymbol subclass
-
-        public TypeSymbol(long flags, Name name, Type type, Symbol owner) {
-            super(TYP, flags, name, type, owner);
+    public static abstract class TypeSymbol extends Symbol {
+        public TypeSymbol(int kind, long flags, Name name, Type type, Symbol owner) {
+            super(kind, flags, name, type, owner);
         }
-
         /** form a fully qualified name from a name and an owner
          */
         static public Name formFullName(Name name, Symbol owner) {
@@ -610,11 +604,7 @@ public abstract class Symbol implements Element {
             return this.type.hasTag(TYPEVAR);
         }
 
-        // For type params; overridden in subclasses.
-        public ElementKind getKind() {
-            return ElementKind.TYPE_PARAMETER;
-        }
-
+        @Override
         public java.util.List<Symbol> getEnclosedElements() {
             List<Symbol> list = List.nil();
             if (kind == TYP && type.hasTag(TYPEVAR)) {
@@ -627,21 +617,29 @@ public abstract class Symbol implements Element {
             return list;
         }
 
-        // For type params.
-        // Perhaps not needed if getEnclosingElement can be spec'ed
-        // to do the same thing.
-        // TODO: getGenericElement() might not be needed
-        public Symbol getGenericElement() {
-            return owner;
+        @Override
+        public <R, P> R accept(Symbol.Visitor<R, P> v, P p) {
+            return v.visitTypeSymbol(this, p);
         }
+    }
 
-        public <R, P> R accept(ElementVisitor<R, P> v, P p) {
-            Assert.check(type.hasTag(TYPEVAR)); // else override will be invoked
-            return v.visitTypeParameter(this, p);
+    /**
+     * Type variables are represented by instances of this class.
+     */
+    public static class TypeVariableSymbol
+            extends TypeSymbol implements TypeParameterElement {
+
+        public TypeVariableSymbol(long flags, Name name, Type type, Symbol owner) {
+            super(TYP, flags, name, type, owner);
         }
 
-        public <R, P> R accept(Symbol.Visitor<R, P> v, P p) {
-            return v.visitTypeSymbol(this, p);
+        public ElementKind getKind() {
+            return ElementKind.TYPE_PARAMETER;
+        }
+
+        @Override
+        public Symbol getGenericElement() {
+            return owner;
         }
 
         public List<Type> getBounds() {
@@ -658,6 +656,11 @@ public abstract class Symbol implements Element {
                 return ct.interfaces_field;
             }
         }
+
+        @Override
+        public <R, P> R accept(ElementVisitor<R, P> v, P p) {
+            return v.visitTypeParameter(this, p);
+        }
     }
 
     /** A class for package symbols
@@ -670,8 +673,7 @@ public abstract class Symbol implements Element {
         public ClassSymbol package_info; // see bug 6443073
 
         public PackageSymbol(Name name, Type type, Symbol owner) {
-            super(0, name, type, owner);
-            this.kind = PCK;
+            super(PCK, 0, name, type, owner);
             this.members_field = null;
             this.fullname = formFullName(name, owner);
         }
@@ -783,7 +785,7 @@ public abstract class Symbol implements Element {
         public Pool pool;
 
         public ClassSymbol(long flags, Name name, Type type, Symbol owner) {
-            super(flags, name, type, owner);
+            super(TYP, flags, name, type, owner);
             this.members_field = null;
             this.fullname = formFullName(name, owner);
             this.flatname = formFlatName(name, owner);

src/share/classes/com/sun/tools/javac/code/Symtab.java

@@ -404,12 +404,11 @@ public class Symtab {
                     return messages.getLocalizedString("compiler.misc.unnamed.package");
                 }
             };
-        noSymbol = new TypeSymbol(0, names.empty, Type.noType, rootPackage) {
+        noSymbol = new TypeSymbol(Kinds.NIL, 0, names.empty, Type.noType, rootPackage) {
             public <R, P> R accept(ElementVisitor<R, P> v, P p) {
                 return v.visitUnknown(this, p);
             }
         };
-        noSymbol.kind = Kinds.NIL;
 
         // create the error symbols
         errSymbol = new ClassSymbol(PUBLIC|STATIC|ACYCLIC, names.any, null, rootPackage);

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

@@ -1145,7 +1145,7 @@ public class Type implements PrimitiveType {
 
         public TypeVar(Name name, Symbol owner, Type lower) {
             super(TYPEVAR, null);
-            tsym = new TypeSymbol(0, name, this, owner);
+            tsym = new TypeVariableSymbol(0, name, this, owner);
             this.lower = lower;
         }
 

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

@@ -262,7 +262,7 @@ public class Infer {
             UndetVar uv = (UndetVar)inferenceContext.asFree(t);
             List<Type> upperBounds = uv.getBounds(InferenceBound.UPPER);
             if (Type.containsAny(upperBounds, vars)) {
-                TypeSymbol fresh_tvar = new TypeSymbol(Flags.SYNTHETIC, uv.qtype.tsym.name, null, uv.qtype.tsym.owner);
+                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);
                 todo.append(uv);
                 uv.inst = fresh_tvar.type;

test/tools/javac/scope/7017664/CompoundScopeTest.java

 /*
- * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2011, 2013, 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
@@ -147,7 +147,7 @@ public class CompoundScopeTest {
         Scope createScope(int nelems) {
             Scope s = new Scope(symtab.noSymbol);
             for (int i = 0 ; i < nelems ; i++) {
-                Symbol sym = new TypeSymbol(0, names.fromString("s" + i), null, null);
+                Symbol sym = new TypeVariableSymbol(0, names.fromString("s" + i), null, null);
                 s.enter(sym);
                 elems = elems.prepend(sym);
                 List<Symbol> shadowed = shadowedMap.get(sym.name);

test/tools/javac/types/TypeHarness.java

 /*
- * Copyright (c) 2010, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2010, 2013, 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
@@ -309,7 +309,7 @@ public class TypeHarness {
         }
 
         public TypeVar TypeVariable(Type bound) {
-            TypeSymbol tvsym = new TypeSymbol(0, syntheticName(), null, predef.noSymbol);
+            TypeSymbol tvsym = new TypeVariableSymbol(0, syntheticName(), null, predef.noSymbol);
             tvsym.type = new TypeVar(tvsym, bound, null);
             return (TypeVar)tvsym.type;
         }