8250625: Compiler implementation of Pattern Matching for instanceof (…

…Final)

Reviewed-by: vromero

src/java.base/share/classes/jdk/internal/PreviewFeature.java

@@ -54,7 +54,6 @@
     public boolean essentialAPI() default false;
 
     public enum Feature {
-        PATTERN_MATCHING_IN_INSTANCEOF,
         // 8242284:
         // The TEXT_BLOCKS enum constant is not used in the JDK 15 codebase, but
         // exists to support the bootcycle build of JDK 15. The bootcycle build

src/java.compiler/share/classes/javax/lang/model/element/ElementKind.java

@@ -121,20 +121,9 @@ public enum ElementKind {
     RECORD_COMPONENT,
 
     /**
-     * {@preview Associated with pattern matching for {@code
-     * instanceof}, a preview feature of the Java language.
-     *
-     *           This enum constant is associated with <i>pattern
-     *           matching for {@code instanceof}</i>, a preview
-     *           feature of the Java language. Preview features
-     *           may be removed in a future release, or upgraded to permanent
-     *           features of the Java language.}
-     *
-     * A binding variable in a pattern .
-     * @since 14
+     * A binding variable in a pattern.
+     * @since 16
      */
-    @jdk.internal.PreviewFeature(feature=jdk.internal.PreviewFeature.Feature.PATTERN_MATCHING_IN_INSTANCEOF,
-                                 essentialAPI=false)
     BINDING_VARIABLE;
 
     /**

src/jdk.compiler/share/classes/com/sun/source/tree/BindingPatternTree.java

@@ -25,34 +25,17 @@
 
 package com.sun.source.tree;
 
-import javax.lang.model.element.Name;
-
 /**
- * {@preview Associated with pattern matching for instanceof, a preview feature of
- *           the Java language.
- *
- *           This interface is associated with <i>pattern matching for instanceof</i>, a preview
- *           feature of the Java language. Preview features
- *           may be removed in a future release, or upgraded to permanent
- *           features of the Java language.}
- *
  * A binding pattern tree
  *
- * @since 14
+ * @since 16
  */
 public interface BindingPatternTree extends PatternTree {
 
     /**
-     * Returns the type of the bind variable.
-     * @return the type
+     * Returns the binding variable.
+     * @return the binding variable
      */
-    Tree getType();
-
-    /**
-     * A binding variable name.
-     * @return the name of the binding variable
-     */
-    Name getBinding();
+    VariableTree getVariable();
 
 }
-

src/jdk.compiler/share/classes/com/sun/source/tree/InstanceOfTree.java

@@ -49,18 +49,11 @@ public interface InstanceOfTree extends ExpressionTree {
     /**
      * Returns the type for which to check.
      * @return the type
+     * @see #getPattern()
      */
     Tree getType();
 
     /**
-     * {@preview Associated with pattern matching for instanceof, a preview feature of
-     *           the Java language.
-     *
-     *           This method is associated with <i>pattern matching for instanceof</i>, a preview
-     *           feature of the Java language. Preview features
-     *           may be removed in a future release, or upgraded to permanent
-     *           features of the Java language.}
-     *
      * Returns the tested pattern, or null if this instanceof does not use
      * a pattern.
      *
@@ -77,7 +70,7 @@ public interface InstanceOfTree extends ExpressionTree {
      * returns null.
      *
      * @return the tested pattern, or null if this instanceof does not use a pattern
-     * @since 14
+     * @since 16
      */
     PatternTree getPattern();
 }

src/jdk.compiler/share/classes/com/sun/source/tree/PatternTree.java

@@ -26,17 +26,9 @@
 package com.sun.source.tree;
 
 /**
- * {@preview Associated with pattern matching for instanceof, a preview feature of
- *           the Java language.
- *
- *           This interface is associated with <i>pattern matching for instanceof</i>, a preview
- *           feature of the Java language. Preview features
- *           may be removed in a future release, or upgraded to permanent
- *           features of the Java language.}
- *
  * A tree node used as the base class for the different kinds of
- * statements.
+ * patterns.
  *
- * @since 14
+ * @since 16
  */
 public interface PatternTree extends Tree {}

src/jdk.compiler/share/classes/com/sun/source/tree/Tree.java

@@ -220,17 +220,9 @@ public enum Kind {
         PARENTHESIZED(ParenthesizedTree.class),
 
         /**
-         * {@preview Associated with pattern matching for instanceof, a preview feature of
-         *           the Java language.
-         *
-         *           This enum constant is associated with <i>pattern matching for instanceof</i>, a preview
-         *           feature of the Java language. Preview features
-         *           may be removed in a future release, or upgraded to permanent
-         *           features of the Java language.}
-         *
          * Used for instances of {@link BindingPatternTree}.
          *
-         * @since 14
+         * @since 16
          */
         BINDING_PATTERN(BindingPatternTree.class),
 

src/jdk.compiler/share/classes/com/sun/source/tree/TreeVisitor.java

@@ -258,19 +258,11 @@ public interface TreeVisitor<R,P> {
     R visitLiteral(LiteralTree node, P p);
 
     /**
-     * {@preview Associated with pattern matching for instanceof, a preview feature of
-     *           the Java language.
-     *
-     *           This method is associated with <i>pattern matching for instanceof</i>, a preview
-     *           feature of the Java language. Preview features
-     *           may be removed in a future release, or upgraded to permanent
-     *           features of the Java language.}
-     *
      * Visits an BindingPattern node.
      * @param node the node being visited
      * @param p a parameter value
      * @return a result value
-     * @since 14
+     * @since 16
      */
     R visitBindingPattern(BindingPatternTree node, P p);
 

src/jdk.compiler/share/classes/com/sun/source/util/TreeScanner.java

@@ -691,7 +691,7 @@ public R visitInstanceOf(InstanceOfTree node, P p) {
      */
     @Override
     public R visitBindingPattern(BindingPatternTree node, P p) {
-        return scan(node.getType(), p);
+        return scan(node.getVariable(), p);
     }
 
     /**

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

@@ -165,9 +165,7 @@ public boolean isEnabled() {
      * @return true, if given feature is a preview feature.
      */
     public boolean isPreview(Feature feature) {
-        if (feature == Feature.PATTERN_MATCHING_IN_INSTANCEOF ||
-            feature == Feature.REIFIABLE_TYPES_INSTANCEOF ||
-            feature == Feature.SEALED_CLASSES)
+        if (feature == Feature.SEALED_CLASSES)
             return true;
         //Note: this is a backdoor which allows to optionally treat all features as 'preview' (for testing).
         //When real preview features will be added, this method can be implemented to return 'true'

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

@@ -1855,7 +1855,7 @@ public Name getSimpleName() {
     public static class BindingSymbol extends VarSymbol {
 
         public BindingSymbol(Name name, Type type, Symbol owner) {
-            super(Flags.FINAL | Flags.HASINIT | Flags.MATCH_BINDING, name, type, owner);
+            super(Flags.HASINIT | Flags.MATCH_BINDING, name, type, owner);
         }
 
         public boolean isAliasFor(BindingSymbol b) {

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

@@ -951,9 +951,8 @@ private Attribute.TypeCompound toTypeCompound(Attribute.Compound a, TypeAnnotati
                                                  " within frame " + frame);
                     }
 
-                case BINDING_PATTERN:
                 case VARIABLE:
-                    VarSymbol v = frame.hasTag(Tag.BINDINGPATTERN) ? ((JCBindingPattern) frame).symbol : ((JCVariableDecl) frame).sym;
+                    VarSymbol v = ((JCVariableDecl) frame).sym;
                     if (v.getKind() != ElementKind.FIELD) {
                         appendTypeAnnotationsToOwner(v, v.getRawTypeAttributes());
                     }

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

@@ -308,8 +308,6 @@ void checkAssignable(DiagnosticPosition pos, VarSymbol v, JCTree base, Env<AttrC
                isAssignableAsBlankFinal(v, env)))) {
             if (v.isResourceVariable()) { //TWR resource
                 log.error(pos, Errors.TryResourceMayNotBeAssigned(v));
-            } else if ((v.flags() & MATCH_BINDING) != 0) {
-                log.error(pos, Errors.PatternBindingMayNotBeAssigned(v));
             } else {
                 log.error(pos, Errors.CantAssignValToFinalVar(v));
             }
@@ -3933,10 +3931,14 @@ public void visitTypeTest(JCInstanceOf tree) {
         if (tree.pattern.getTag() == BINDINGPATTERN) {
             attribTree(tree.pattern, env, unknownExprInfo);
             clazztype = tree.pattern.type;
+            if (types.isSubtype(exprtype, clazztype) &&
+                !exprtype.isErroneous() && !clazztype.isErroneous()) {
+                log.error(tree.pos(), Errors.InstanceofPatternNoSubtype(clazztype, exprtype));
+            }
             JCBindingPattern pattern = (JCBindingPattern) tree.pattern;
-            typeTree = pattern.vartype;
+            typeTree = pattern.var.vartype;
             if (!clazztype.hasTag(TYPEVAR)) {
-                clazztype = chk.checkClassOrArrayType(pattern.vartype.pos(), clazztype);
+                clazztype = chk.checkClassOrArrayType(pattern.var.vartype.pos(), clazztype);
             }
         } else {
             clazztype = attribType(tree.pattern, env);
@@ -3962,7 +3964,9 @@ public void visitTypeTest(JCInstanceOf tree) {
                     valid = true;
                 }
             } else {
-                log.error(typeTree.pos(), Errors.IllegalGenericTypeForInstof);
+                log.error(DiagnosticFlag.SOURCE_LEVEL, tree.pos(),
+                          Feature.REIFIABLE_TYPES_INSTANCEOF.error(this.sourceName));
+                allowReifiableTypesInInstanceof = true;
             }
             if (!valid) {
                 clazztype = types.createErrorType(clazztype);
@@ -3975,15 +3979,17 @@ public void visitTypeTest(JCInstanceOf tree) {
 
     public void visitBindingPattern(JCBindingPattern tree) {
         ResultInfo varInfo = new ResultInfo(KindSelector.TYP, resultInfo.pt, resultInfo.checkContext);
-        tree.type = attribTree(tree.vartype, env, varInfo);
-        VarSymbol v = tree.symbol = new BindingSymbol(tree.name, tree.vartype.type, env.info.scope.owner);
-        if (chk.checkUnique(tree.pos(), v, env.info.scope)) {
-            chk.checkTransparentVar(tree.pos(), v, env.info.scope);
-        }
-        annotate.queueScanTreeAndTypeAnnotate(tree.vartype, env, v, tree.pos());
+        tree.type = tree.var.type = attribTree(tree.var.vartype, env, varInfo);
+        BindingSymbol v = new BindingSymbol(tree.var.name, tree.var.vartype.type, env.info.scope.owner);
+        v.pos = tree.pos;
+        tree.var.sym = v;
+        if (chk.checkUnique(tree.var.pos(), v, env.info.scope)) {
+            chk.checkTransparentVar(tree.var.pos(), v, env.info.scope);
+        }
+        annotate.queueScanTreeAndTypeAnnotate(tree.var.vartype, env, v, tree.var.pos());
         annotate.flush();
         result = tree.type;
-        matchBindings = new MatchBindings(List.of(tree.symbol), List.nil());
+        matchBindings = new MatchBindings(List.of(v), List.nil());
     }
 
     public void visitIndexed(JCArrayAccess tree) {
@@ -5733,9 +5739,9 @@ public void visitVarDef(JCVariableDecl that) {
 
         @Override
         public void visitBindingPattern(JCBindingPattern that) {
-            if (that.symbol == null) {
-                that.symbol = new BindingSymbol(that.name, that.type, syms.noSymbol);
-                that.symbol.adr = 0;
+            if (that.var.sym == null) {
+                that.var.sym = new BindingSymbol(that.var.name, that.var.type, syms.noSymbol);
+                that.var.sym.adr = 0;
             }
             super.visitBindingPattern(that);
         }

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

@@ -1875,7 +1875,8 @@ void checkInit(DiagnosticPosition pos, VarSymbol sym) {
         void checkInit(DiagnosticPosition pos, VarSymbol sym, Error errkey) {
             if ((sym.adr >= firstadr || sym.owner.kind != TYP) &&
                 trackable(sym) &&
-                !inits.isMember(sym.adr)) {
+                !inits.isMember(sym.adr) &&
+                (sym.flags_field & CLASH) == 0) {
                     log.error(pos, errkey);
                 inits.incl(sym.adr);
             }
@@ -2758,6 +2759,12 @@ public void visitIdent(JCIdent tree) {
             }
         }
 
+        @Override
+        public void visitBindingPattern(JCBindingPattern tree) {
+            super.visitBindingPattern(tree);
+            initParam(tree.var);
+        }
+
         void referenced(Symbol sym) {
             unrefdResources.remove(sym);
         }

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

@@ -148,6 +148,7 @@ private List<BindingSymbol> intersection(DiagnosticPosition pos, List<BindingSym
                     (v1.flags() & CLASH) == 0 &&
                     (v2.flags() & CLASH) == 0) {
                     log.error(pos, Errors.MatchBindingExists);
+                    v2.flags_field |= CLASH;
                     list = list.append(v2);
                 }
             }
@@ -166,6 +167,7 @@ private final List<BindingSymbol> union(DiagnosticPosition pos, List<BindingSymb
                         (ov.flags() & CLASH) == 0 &&
                         (v.flags() & CLASH) == 0) {
                         log.error(pos, Errors.MatchBindingExists);
+                        v.flags_field |= CLASH;
                     }
                 }
                 list = list.append(v);

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

@@ -153,20 +153,20 @@ public void visitTypeTest(JCInstanceOf tree) {
             //=>
             //(let T' N$temp = E; N$temp instanceof T && (N = (T) N$temp == (T) N$temp))
             JCBindingPattern patt = (JCBindingPattern)tree.pattern;
-            VarSymbol pattSym = patt.symbol;
+            VarSymbol pattSym = patt.var.sym;
             Type tempType = tree.expr.type.hasTag(BOT) ?
                     syms.objectType
                     : tree.expr.type;
             VarSymbol temp = new VarSymbol(pattSym.flags() | Flags.SYNTHETIC,
                     names.fromString(pattSym.name.toString() + target.syntheticNameChar() + "temp"),
                     tempType,
-                    patt.symbol.owner);
+                    patt.var.sym.owner);
             JCExpression translatedExpr = translate(tree.expr);
             Type castTargetType = types.boxedTypeOrType(pattSym.erasure(types));
 
             result = makeTypeTest(make.Ident(temp), make.Type(castTargetType));
 
-            VarSymbol bindingVar = bindingContext.bindingDeclared(patt.symbol);
+            VarSymbol bindingVar = bindingContext.bindingDeclared((BindingSymbol) patt.var.sym);
             if (bindingVar != null) { //TODO: cannot be null here?
                 JCAssign fakeInit = (JCAssign)make.at(tree.pos).Assign(
                         make.Ident(bindingVar), convert(make.Ident(temp), castTargetType)).setType(bindingVar.erasure(types));

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

@@ -568,9 +568,7 @@ public void visitCase(JCCase tree) {
     }
 
     public void visitBindingPattern(JCBindingPattern tree) {
-        if (tree.vartype != null) {
-            tree.vartype = translate(tree.vartype, null);
-        }
+        tree.var = translate(tree.var, null);
         result = tree;
     }
 

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

@@ -257,13 +257,10 @@ && scan(tree.rhs, that.rhs)
     @Override
     public void visitBindingPattern(JCBindingPattern tree) {
         JCBindingPattern that = (JCBindingPattern) parameter;
-        result =
-                scan(tree.vartype, that.vartype)
-                        && tree.name == that.name;
+        result = scan(tree.var, that.var);
         if (!result) {
             return;
         }
-        equiv.put(tree.symbol, that.symbol);
     }
 
     @Override

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

@@ -106,12 +106,6 @@ public void visitSelect(JCFieldAccess tree) {
         super.visitSelect(tree);
     }
 
-    @Override
-    public void visitBindingPattern(JCTree.JCBindingPattern tree) {
-        symbolHashes.computeIfAbsent(tree.symbol, k -> symbolHashes.size());
-        super.visitBindingPattern(tree);
-    }
-
     @Override
     public void visitVarDef(JCVariableDecl tree) {
         symbolHashes.computeIfAbsent(tree.sym, k -> symbolHashes.size());

src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java

@@ -932,10 +932,18 @@ JCExpression term2Rest(JCExpression t, int minprec) {
             if (token.kind == INSTANCEOF) {
                 int pos = token.pos;
                 nextToken();
-                JCTree pattern = parseType();
+                int typePos = token.pos;
+                JCExpression type = parseType();
+                JCTree pattern;
                 if (token.kind == IDENTIFIER) {
                     checkSourceLevel(token.pos, Feature.PATTERN_MATCHING_IN_INSTANCEOF);
-                    pattern = toP(F.at(token.pos).BindingPattern(ident(), pattern));
+                    JCModifiers mods = F.at(Position.NOPOS).Modifiers(0);
+                    JCVariableDecl var = toP(F.at(token.pos).VarDef(mods, ident(), type, null));
+                    TreeInfo.getStartPos(var);
+                    pattern = toP(F.at(typePos).BindingPattern(var));
+                    TreeInfo.getStartPos(pattern);
+                } else {
+                    pattern = type;
                 }
                 odStack[top] = F.at(pos).TypeTest(odStack[top], pattern);
             } else {