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"nb-javac" is a patched version of OpenJDK "javac", i.e., the Java compiler. This has long been part of NetBeans, providing a highly tuned Java compiler specifically for the Java editor i.e., parsing and lexing for features such as syntax coloring, code completion.

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/*
 * Copyright (c) 1999, 2022, 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * 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.
 */

package com.sun.tools.javac.comp;

import java.util.*;
import java.util.function.BiConsumer;
import java.util.function.Predicate;
import java.util.function.Supplier;

import javax.lang.model.element.ElementKind;
import javax.lang.model.element.NestingKind;
import javax.tools.JavaFileManager;

import com.sun.source.tree.CaseTree;
import com.sun.tools.javac.code.*;
import com.sun.tools.javac.code.Attribute.Compound;
import com.sun.tools.javac.code.Directive.ExportsDirective;
import com.sun.tools.javac.code.Directive.RequiresDirective;
import com.sun.tools.javac.code.Source.Feature;
import com.sun.tools.javac.comp.Annotate.AnnotationTypeMetadata;
import com.sun.tools.javac.jvm.*;
import com.sun.tools.javac.resources.CompilerProperties.Errors;
import com.sun.tools.javac.resources.CompilerProperties.Fragments;
import com.sun.tools.javac.resources.CompilerProperties.Warnings;
import com.sun.tools.javac.tree.*;
import com.sun.tools.javac.util.*;
import com.sun.tools.javac.util.JCDiagnostic.DiagnosticFlag;
import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
import com.sun.tools.javac.util.JCDiagnostic.Error;
import com.sun.tools.javac.util.JCDiagnostic.Fragment;
import com.sun.tools.javac.util.JCDiagnostic.Warning;
import com.sun.tools.javac.util.List;

import com.sun.tools.javac.code.Lint;
import com.sun.tools.javac.code.Lint.LintCategory;
import com.sun.tools.javac.code.Scope.WriteableScope;
import com.sun.tools.javac.code.Type.*;
import com.sun.tools.javac.code.Symbol.*;
import com.sun.tools.javac.comp.DeferredAttr.DeferredAttrContext;
import com.sun.tools.javac.tree.JCTree.*;

import static com.sun.tools.javac.code.Flags.*;
import static com.sun.tools.javac.code.Flags.ANNOTATION;
import static com.sun.tools.javac.code.Flags.SYNCHRONIZED;
import static com.sun.tools.javac.code.Kinds.*;
import static com.sun.tools.javac.code.Kinds.Kind.*;
import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
import static com.sun.tools.javac.code.TypeTag.*;
import static com.sun.tools.javac.code.TypeTag.WILDCARD;

import static com.sun.tools.javac.tree.JCTree.Tag.*;
import javax.lang.model.element.Element;
import javax.lang.model.element.ExecutableElement;
import javax.lang.model.element.TypeElement;
import javax.lang.model.type.DeclaredType;
import javax.lang.model.type.TypeMirror;
import javax.lang.model.util.ElementFilter;
import javax.lang.model.util.ElementKindVisitor14;
import nbjavac.ObjectsWrapper;

/** Type checking helper class for the attribution phase.
 *
 *  

This is NOT part of any supported API. * If you write code that depends on this, you do so at your own risk. * This code and its internal interfaces are subject to change or * deletion without notice. */ public class Check { protected static final Context.Key checkKey = new Context.Key<>(); private final Names names; private final Log log; private final Resolve rs; private final Symtab syms; private final Enter enter; private final DeferredAttr deferredAttr; private final Infer infer; private final Types types; private final TypeAnnotations typeAnnotations; private final JCDiagnostic.Factory diags; private final JavaFileManager fileManager; private final Source source; private final Target target; private final Profile profile; private final Preview preview; private final boolean warnOnAnyAccessToMembers; // The set of lint options currently in effect. It is initialized // from the context, and then is set/reset as needed by Attr as it // visits all the various parts of the trees during attribution. private Lint lint; // The method being analyzed in Attr - it is set/reset as needed by // Attr as it visits new method declarations. private MethodSymbol method; public static Check instance(Context context) { Check instance = context.get(checkKey); if (instance == null) instance = new Check(context); return instance; } protected Check(Context context) { context.put(checkKey, this); names = Names.instance(context); log = Log.instance(context); rs = Resolve.instance(context); syms = Symtab.instance(context); enter = Enter.instance(context); deferredAttr = DeferredAttr.instance(context); infer = Infer.instance(context); types = Types.instance(context); typeAnnotations = TypeAnnotations.instance(context); diags = JCDiagnostic.Factory.instance(context); Options options = Options.instance(context); lint = Lint.instance(context); fileManager = context.get(JavaFileManager.class); source = Source.instance(context); target = Target.instance(context); warnOnAnyAccessToMembers = options.isSet("warnOnAccessToMembers"); Target target = Target.instance(context); syntheticNameChar = target.syntheticNameChar(); profile = Profile.instance(context); preview = Preview.instance(context); boolean verboseDeprecated = lint.isEnabled(LintCategory.DEPRECATION); boolean verboseRemoval = lint.isEnabled(LintCategory.REMOVAL); boolean verboseUnchecked = lint.isEnabled(LintCategory.UNCHECKED); boolean enforceMandatoryWarnings = true; deprecationHandler = new MandatoryWarningHandler(log, null, verboseDeprecated, enforceMandatoryWarnings, "deprecated", LintCategory.DEPRECATION); removalHandler = new MandatoryWarningHandler(log, null, verboseRemoval, enforceMandatoryWarnings, "removal", LintCategory.REMOVAL); uncheckedHandler = new MandatoryWarningHandler(log, null, verboseUnchecked, enforceMandatoryWarnings, "unchecked", LintCategory.UNCHECKED); sunApiHandler = new MandatoryWarningHandler(log, null, false, enforceMandatoryWarnings, "sunapi", null); deferredLintHandler = DeferredLintHandler.instance(context); allowModules = Feature.MODULES.allowedInSource(source); allowRecords = Feature.RECORDS.allowedInSource(source); allowSealed = Feature.SEALED_CLASSES.allowedInSource(source); } /** Character for synthetic names */ char syntheticNameChar; /** A table mapping flat names of all compiled classes for each module in this run * to their symbols; maintained from outside. */ private Map,ClassSymbol> compiled = new HashMap<>(); /** A handler for messages about deprecated usage. */ private MandatoryWarningHandler deprecationHandler; /** A handler for messages about deprecated-for-removal usage. */ private MandatoryWarningHandler removalHandler; /** A handler for messages about unchecked or unsafe usage. */ private MandatoryWarningHandler uncheckedHandler; /** A handler for messages about using proprietary API. */ private MandatoryWarningHandler sunApiHandler; /** A handler for deferred lint warnings. */ private DeferredLintHandler deferredLintHandler; /** Are modules allowed */ private final boolean allowModules; /** Are records allowed */ private final boolean allowRecords; /** Are sealed classes allowed */ private final boolean allowSealed; /* ************************************************************************* * Errors and Warnings **************************************************************************/ Lint setLint(Lint newLint) { Lint prev = lint; lint = newLint; return prev; } MethodSymbol setMethod(MethodSymbol newMethod) { MethodSymbol prev = method; method = newMethod; return prev; } /** Warn about deprecated symbol. * @param pos Position to be used for error reporting. * @param sym The deprecated symbol. */ void warnDeprecated(DiagnosticPosition pos, Symbol sym) { if (sym.isDeprecatedForRemoval()) { if (!lint.isSuppressed(LintCategory.REMOVAL)) { if (sym.kind == MDL) { removalHandler.report(pos, Warnings.HasBeenDeprecatedForRemovalModule(sym)); } else { removalHandler.report(pos, Warnings.HasBeenDeprecatedForRemoval(sym, sym.location())); } } } else if (!lint.isSuppressed(LintCategory.DEPRECATION)) { if (sym.kind == MDL) { deprecationHandler.report(pos, Warnings.HasBeenDeprecatedModule(sym)); } else { deprecationHandler.report(pos, Warnings.HasBeenDeprecated(sym, sym.location())); } } } /** Log a preview warning. * @param pos Position to be used for error reporting. * @param msg A Warning describing the problem. */ public void warnPreviewAPI(DiagnosticPosition pos, Warning warnKey) { if (!lint.isSuppressed(LintCategory.PREVIEW)) preview.reportPreviewWarning(pos, warnKey); } /** Log a preview warning. * @param pos Position to be used for error reporting. * @param msg A Warning describing the problem. */ public void warnDeclaredUsingPreview(DiagnosticPosition pos, Symbol sym) { if (!lint.isSuppressed(LintCategory.PREVIEW)) preview.reportPreviewWarning(pos, Warnings.DeclaredUsingPreview(kindName(sym), sym)); } /** Warn about unchecked operation. * @param pos Position to be used for error reporting. * @param msg A string describing the problem. */ public void warnUnchecked(DiagnosticPosition pos, Warning warnKey) { if (!lint.isSuppressed(LintCategory.UNCHECKED)) uncheckedHandler.report(pos, warnKey); } /** Warn about unsafe vararg method decl. * @param pos Position to be used for error reporting. */ void warnUnsafeVararg(DiagnosticPosition pos, Warning warnKey) { if (lint.isEnabled(LintCategory.VARARGS)) log.warning(LintCategory.VARARGS, pos, warnKey); } public void warnStatic(DiagnosticPosition pos, Warning warnKey) { if (lint.isEnabled(LintCategory.STATIC)) log.warning(LintCategory.STATIC, pos, warnKey); } /** Warn about division by integer constant zero. * @param pos Position to be used for error reporting. */ void warnDivZero(DiagnosticPosition pos) { if (lint.isEnabled(LintCategory.DIVZERO)) log.warning(LintCategory.DIVZERO, pos, Warnings.DivZero); } /** * Report any deferred diagnostics. */ public void reportDeferredDiagnostics() { deprecationHandler.reportDeferredDiagnostic(); removalHandler.reportDeferredDiagnostic(); uncheckedHandler.reportDeferredDiagnostic(); sunApiHandler.reportDeferredDiagnostic(); } /** Report a failure to complete a class. * @param pos Position to be used for error reporting. * @param ex The failure to report. */ public Type completionError(DiagnosticPosition pos, CompletionFailure ex) { log.error(JCDiagnostic.DiagnosticFlag.NON_DEFERRABLE, pos, Errors.CantAccess(ex.sym, ex.getDetailValue())); return syms.errType; } /** Report an error that wrong type tag was found. * @param pos Position to be used for error reporting. * @param required An internationalized string describing the type tag * required. * @param found The type that was found. */ Type typeTagError(DiagnosticPosition pos, JCDiagnostic required, Object found) { // this error used to be raised by the parser, // but has been delayed to this point: if (found instanceof Type type && type.hasTag(VOID)) { log.error(pos, Errors.IllegalStartOfType); return syms.errType; } log.error(pos, Errors.TypeFoundReq(found, required)); return types.createErrorType(found instanceof Type type ? type : syms.errType); } /** Report an error that symbol cannot be referenced before super * has been called. * @param pos Position to be used for error reporting. * @param sym The referenced symbol. */ void earlyRefError(DiagnosticPosition pos, Symbol sym) { log.error(pos, Errors.CantRefBeforeCtorCalled(sym)); } /** Report duplicate declaration error. */ void duplicateError(DiagnosticPosition pos, Symbol sym) { if (!sym.type.isErroneous()) { Symbol location = sym.location(); if (location.kind == MTH && ((MethodSymbol)location).isStaticOrInstanceInit()) { log.error(pos, Errors.AlreadyDefinedInClinit(kindName(sym), sym, kindName(sym.location()), kindName(sym.location().enclClass()), sym.location().enclClass())); } else { /* dont error if this is a duplicated parameter of a generated canonical constructor * as we should have issued an error for the duplicated fields */ if (location.kind != MTH || ((sym.owner.flags_field & GENERATEDCONSTR) == 0) || ((sym.owner.flags_field & RECORD) == 0)) { log.error(pos, Errors.AlreadyDefined(kindName(sym), sym, kindName(sym.location()), sym.location())); } } } } /** Report array/varargs duplicate declaration */ void varargsDuplicateError(DiagnosticPosition pos, Symbol sym1, Symbol sym2) { if (!sym1.type.isErroneous() && !sym2.type.isErroneous()) { log.error(pos, Errors.ArrayAndVarargs(sym1, sym2, sym2.location())); } } /* ************************************************************************ * duplicate declaration checking *************************************************************************/ /** Check that variable does not hide variable with same name in * immediately enclosing local scope. * @param pos Position for error reporting. * @param v The symbol. * @param s The scope. */ void checkTransparentVar(DiagnosticPosition pos, VarSymbol v, Scope s) { for (Symbol sym : s.getSymbolsByName(v.name)) { if (sym.owner != v.owner) break; if (sym.kind == VAR && sym.owner.kind.matches(KindSelector.VAL_MTH) && v.name != names.error) { duplicateError(pos, sym); return; } } } /** Check that a class or interface does not hide a class or * interface with same name in immediately enclosing local scope. * @param pos Position for error reporting. * @param c The symbol. * @param s The scope. */ void checkTransparentClass(DiagnosticPosition pos, ClassSymbol c, Scope s) { for (Symbol sym : s.getSymbolsByName(c.name)) { if (sym.owner != c.owner) break; if (sym.kind == TYP && !sym.type.hasTag(TYPEVAR) && sym.owner.kind.matches(KindSelector.VAL_MTH) && c.name != names.error) { duplicateError(pos, sym); return; } } } /** Check that class does not have the same name as one of * its enclosing classes, or as a class defined in its enclosing scope. * return true if class is unique in its enclosing scope. * @param pos Position for error reporting. * @param name The class name. * @param s The enclosing scope. */ boolean checkUniqueClassName(DiagnosticPosition pos, Name name, Scope s) { for (Symbol sym : s.getSymbolsByName(name, NON_RECURSIVE)) { if (sym.kind == TYP && sym.name != names.error) { duplicateError(pos, sym); return false; } } for (Symbol sym = s.owner; sym != null; sym = sym.owner) { if (sym.kind == TYP && sym.name == name && sym.name != names.error) { duplicateError(pos, sym); return true; } } return true; } /* ************************************************************************* * Class name generation **************************************************************************/ private Map, Integer> localClassNameIndexes = new HashMap<>(); /** Return name of local class. * This is of the form {@code $ n } * where * enclClass is the flat name of the enclosing class, * classname is the simple name of the local class */ public Name localClassName(ClassSymbol c) { Name enclFlatname = c.owner.enclClass().flatname; String enclFlatnameStr = enclFlatname.toString(); Pair key = new Pair<>(enclFlatname, c.name); Integer index = localClassNameIndexes.get(key); for (int i = (index == null) ? 1 : index; ; i++) { Name flatname = names.fromString(enclFlatnameStr + syntheticNameChar + i + c.name); if (getCompiled(c.packge().modle, flatname) == null) { localClassNameIndexes.put(key, i + 1); return flatname; } } } public void clearLocalClassNameIndexes(ClassSymbol c) { if (c.owner != null && c.owner.kind != NIL) { localClassNameIndexes.remove(new Pair<>( c.owner.enclClass().flatname, c.name)); } } public void newRound() { compiled.clear(); localClassNameIndexes.clear(); } public void clear() { deprecationHandler.clear(); removalHandler.clear(); uncheckedHandler.clear(); sunApiHandler.clear(); } public void putCompiled(ClassSymbol csym) { compiled.put(Pair.of(csym.packge().modle, csym.flatname), csym); } public ClassSymbol getCompiled(ClassSymbol csym) { return compiled.get(Pair.of(csym.packge().modle, csym.flatname)); } public ClassSymbol getCompiled(ModuleSymbol msym, Name flatname) { return compiled.get(Pair.of(msym, flatname)); } public void removeCompiled(ClassSymbol csym) { compiled.remove(Pair.of(csym.packge().modle, csym.flatname)); } /* ************************************************************************* * Type Checking **************************************************************************/ /** * A check context is an object that can be used to perform compatibility * checks - depending on the check context, meaning of 'compatibility' might * vary significantly. */ public interface CheckContext { /** * Is type 'found' compatible with type 'req' in given context */ boolean compatible(Type found, Type req, Warner warn); /** * Report a check error */ void report(DiagnosticPosition pos, JCDiagnostic details); /** * Obtain a warner for this check context */ public Warner checkWarner(DiagnosticPosition pos, Type found, Type req); public InferenceContext inferenceContext(); public DeferredAttr.DeferredAttrContext deferredAttrContext(); } /** * This class represent a check context that is nested within another check * context - useful to check sub-expressions. The default behavior simply * redirects all method calls to the enclosing check context leveraging * the forwarding pattern. */ static class NestedCheckContext implements CheckContext { CheckContext enclosingContext; NestedCheckContext(CheckContext enclosingContext) { this.enclosingContext = enclosingContext; } public boolean compatible(Type found, Type req, Warner warn) { return enclosingContext.compatible(found, req, warn); } public void report(DiagnosticPosition pos, JCDiagnostic details) { enclosingContext.report(pos, details); } public Warner checkWarner(DiagnosticPosition pos, Type found, Type req) { return enclosingContext.checkWarner(pos, found, req); } public InferenceContext inferenceContext() { return enclosingContext.inferenceContext(); } public DeferredAttrContext deferredAttrContext() { return enclosingContext.deferredAttrContext(); } } /** * Check context to be used when evaluating assignment/return statements */ CheckContext basicHandler = new CheckContext() { public void report(DiagnosticPosition pos, JCDiagnostic details) { log.error(pos, Errors.ProbFoundReq(details)); } public boolean compatible(Type found, Type req, Warner warn) { return types.isAssignable(found, req, warn); } public Warner checkWarner(DiagnosticPosition pos, Type found, Type req) { return convertWarner(pos, found, req); } public InferenceContext inferenceContext() { return infer.emptyContext; } public DeferredAttrContext deferredAttrContext() { return deferredAttr.emptyDeferredAttrContext; } @Override public String toString() { return "CheckContext: basicHandler"; } }; /** Check that a given type is assignable to a given proto-type. * If it is, return the type, otherwise return errType. * @param pos Position to be used for error reporting. * @param found The type that was found. * @param req The type that was required. */ public Type checkType(DiagnosticPosition pos, Type found, Type req) { return checkType(pos, found, req, basicHandler); } Type checkType(final DiagnosticPosition pos, final Type found, final Type req, final CheckContext checkContext) { final InferenceContext inferenceContext = checkContext.inferenceContext(); if (inferenceContext.free(req) || inferenceContext.free(found)) { inferenceContext.addFreeTypeListener(List.of(req, found), solvedContext -> checkType(pos, solvedContext.asInstType(found), solvedContext.asInstType(req), checkContext)); } if (req.hasTag(ERROR)) return req; if (req.hasTag(NONE)) return found; if (checkContext.compatible(found, req, checkContext.checkWarner(pos, found, req))) { return found; } else { if (found.isNumeric() && req.isNumeric()) { checkContext.report(pos, diags.fragment(Fragments.PossibleLossOfPrecision(found, req))); return types.createErrorType(found); } checkContext.report(pos, diags.fragment(Fragments.InconvertibleTypes(found, req))); return types.createErrorType(found); } } /** Check that a given type can be cast to a given target type. * Return the result of the cast. * @param pos Position to be used for error reporting. * @param found The type that is being cast. * @param req The target type of the cast. */ Type checkCastable(DiagnosticPosition pos, Type found, Type req) { return checkCastable(pos, found, req, basicHandler); } Type checkCastable(DiagnosticPosition pos, Type found, Type req, CheckContext checkContext) { if (types.isCastable(found, req, castWarner(pos, found, req))) { return req; } else { checkContext.report(pos, diags.fragment(Fragments.InconvertibleTypes(found, req))); return types.createErrorType(found); } } /** Check for redundant casts (i.e. where source type is a subtype of target type) * The problem should only be reported for non-292 cast */ public void checkRedundantCast(Env env, final JCTypeCast tree) { if (!tree.type.isErroneous() && types.isSameType(tree.expr.type, tree.clazz.type) && !(ignoreAnnotatedCasts && TreeInfo.containsTypeAnnotation(tree.clazz)) && !is292targetTypeCast(tree)) { deferredLintHandler.report(() -> { if (lint.isEnabled(LintCategory.CAST)) log.warning(LintCategory.CAST, tree.pos(), Warnings.RedundantCast(tree.clazz.type)); }); } } //where private boolean is292targetTypeCast(JCTypeCast tree) { boolean is292targetTypeCast = false; JCExpression expr = TreeInfo.skipParens(tree.expr); if (expr.hasTag(APPLY)) { JCMethodInvocation apply = (JCMethodInvocation)expr; Symbol sym = TreeInfo.symbol(apply.meth); is292targetTypeCast = sym != null && sym.kind == MTH && (sym.flags() & HYPOTHETICAL) != 0; } return is292targetTypeCast; } private static final boolean ignoreAnnotatedCasts = true; /** Check that a type is within some bounds. * * Used in TypeApply to verify that, e.g., X in {@code V} is a valid * type argument. * @param a The type that should be bounded by bs. * @param bound The bound. */ private boolean checkExtends(Type a, Type bound) { if (a.isUnbound()) { return true; } else if (!a.hasTag(WILDCARD)) { a = types.cvarUpperBound(a); return types.isSubtype(a, bound); } else if (a.isExtendsBound()) { return types.isCastable(bound, types.wildUpperBound(a), types.noWarnings); } else if (a.isSuperBound()) { return !types.notSoftSubtype(types.wildLowerBound(a), bound); } return true; } /** Check that type is different from 'void'. * @param pos Position to be used for error reporting. * @param t The type to be checked. */ Type checkNonVoid(DiagnosticPosition pos, Type t) { if (t.hasTag(VOID)) { log.error(pos, Errors.VoidNotAllowedHere); return types.createErrorType(t); } else { return t; } } Type checkClassOrArrayType(DiagnosticPosition pos, Type t) { if (!t.hasTag(CLASS) && !t.hasTag(ARRAY) && !t.hasTag(ERROR)) { return typeTagError(pos, diags.fragment(Fragments.TypeReqClassArray), asTypeParam(t)); } else { return t; } } /** Check that type is a class or interface type. * @param pos Position to be used for error reporting. * @param t The type to be checked. */ Type checkClassType(DiagnosticPosition pos, Type t) { if (!t.hasTag(CLASS) && !t.hasTag(ERROR)) { return typeTagError(pos, diags.fragment(Fragments.TypeReqClass), asTypeParam(t)); } else { return t; } } //where private Object asTypeParam(Type t) { return (t.hasTag(TYPEVAR)) ? diags.fragment(Fragments.TypeParameter(t)) : t; } /** Check that type is a valid qualifier for a constructor reference expression */ Type checkConstructorRefType(DiagnosticPosition pos, Type t) { t = checkClassOrArrayType(pos, t); if (t.hasTag(CLASS)) { if ((t.tsym.flags() & (ABSTRACT | INTERFACE)) != 0) { log.error(pos, Errors.AbstractCantBeInstantiated(t.tsym)); t = types.createErrorType(t); } else if ((t.tsym.flags() & ENUM) != 0) { log.error(pos, Errors.EnumCantBeInstantiated); t = types.createErrorType(t); } else { t = checkClassType(pos, t, true); } } else if (t.hasTag(ARRAY)) { if (!types.isReifiable(((ArrayType)t).elemtype)) { log.error(pos, Errors.GenericArrayCreation); t = types.createErrorType(t); } } return t; } /** Check that type is a class or interface type. * @param pos Position to be used for error reporting. * @param t The type to be checked. * @param noBounds True if type bounds are illegal here. */ Type checkClassType(DiagnosticPosition pos, Type t, boolean noBounds) { t = checkClassType(pos, t); if (noBounds && t.isParameterized()) { List args = t.getTypeArguments(); while (args.nonEmpty()) { if (args.head.hasTag(WILDCARD)) return typeTagError(pos, diags.fragment(Fragments.TypeReqExact), args.head); args = args.tail; } } return t; } /** Check that type is a reference type, i.e. a class, interface or array type * or a type variable. * @param pos Position to be used for error reporting. * @param t The type to be checked. */ Type checkRefType(DiagnosticPosition pos, Type t) { if (t.isReference()) return t; else return typeTagError(pos, diags.fragment(Fragments.TypeReqRef), t); } /** Check that each type is a reference type, i.e. a class, interface or array type * or a type variable. * @param trees Original trees, used for error reporting. * @param types The types to be checked. */ List checkRefTypes(List trees, List types) { List tl = trees; for (List l = types; l.nonEmpty(); l = l.tail) { l.head = checkRefType(tl.head.pos(), l.head); tl = tl.tail; } return types; } /** Check that type is a null or reference type. * @param pos Position to be used for error reporting. * @param t The type to be checked. */ Type checkNullOrRefType(DiagnosticPosition pos, Type t) { if (t.isReference() || t.hasTag(BOT)) return t; else return typeTagError(pos, diags.fragment(Fragments.TypeReqRef), t); } /** Check that flag set does not contain elements of two conflicting sets. s * Return true if it doesn't. * @param pos Position to be used for error reporting. * @param flags The set of flags to be checked. * @param set1 Conflicting flags set #1. * @param set2 Conflicting flags set #2. */ boolean checkDisjoint(DiagnosticPosition pos, long flags, long set1, long set2) { if ((flags & set1) != 0 && (flags & set2) != 0) { log.error(pos, Errors.IllegalCombinationOfModifiers(asFlagSet(TreeInfo.firstFlag(flags & set1)), asFlagSet(TreeInfo.firstFlag(flags & set2)))); return false; } else return true; } /** Check that usage of diamond operator is correct (i.e. diamond should not * be used with non-generic classes or in anonymous class creation expressions) */ Type checkDiamond(JCNewClass tree, Type t) { if (!TreeInfo.isDiamond(tree) || t.isErroneous()) { return checkClassType(tree.clazz.pos(), t, true); } else { if (tree.def != null && !Feature.DIAMOND_WITH_ANONYMOUS_CLASS_CREATION.allowedInSource(source)) { log.error(DiagnosticFlag.SOURCE_LEVEL, tree.clazz.pos(), Errors.CantApplyDiamond1(t, Feature.DIAMOND_WITH_ANONYMOUS_CLASS_CREATION.fragment(source.name))); } if (t.tsym.type.getTypeArguments().isEmpty()) { log.error(tree.clazz.pos(), Errors.CantApplyDiamond1(t, Fragments.DiamondNonGeneric(t))); return types.createErrorType(t); } else if (tree.typeargs != null && tree.typeargs.nonEmpty()) { log.error(tree.clazz.pos(), Errors.CantApplyDiamond1(t, Fragments.DiamondAndExplicitParams(t))); return types.createErrorType(t); } else { return t; } } } /** Check that the type inferred using the diamond operator does not contain * non-denotable types such as captured types or intersection types. * @param t the type inferred using the diamond operator * @return the (possibly empty) list of non-denotable types. */ List checkDiamondDenotable(ClassType t) { ListBuffer buf = new ListBuffer<>(); for (Type arg : t.allparams()) { if (!checkDenotable(arg)) { buf.append(arg); } } return buf.toList(); } public boolean checkDenotable(Type t) { return denotableChecker.visit(t, null); } // where /** diamondTypeChecker: A type visitor that descends down the given type looking for non-denotable * types. The visit methods return false as soon as a non-denotable type is encountered and true * otherwise. */ private static final Types.SimpleVisitor denotableChecker = new Types.SimpleVisitor() { @Override public Boolean visitType(Type t, Void s) { return true; } @Override public Boolean visitClassType(ClassType t, Void s) { if (t.isUnion() || t.isIntersection()) { return false; } for (Type targ : t.allparams()) { if (!visit(targ, s)) { return false; } } return true; } @Override public Boolean visitTypeVar(TypeVar t, Void s) { /* Any type variable mentioned in the inferred type must have been declared as a type parameter (i.e cannot have been produced by inference (18.4)) */ return (t.tsym.flags() & SYNTHETIC) == 0; } @Override public Boolean visitCapturedType(CapturedType t, Void s) { /* Any type variable mentioned in the inferred type must have been declared as a type parameter (i.e cannot have been produced by capture conversion (5.1.10)) */ return false; } @Override public Boolean visitArrayType(ArrayType t, Void s) { return visit(t.elemtype, s); } @Override public Boolean visitWildcardType(WildcardType t, Void s) { return visit(t.type, s); } }; void checkVarargsMethodDecl(Env env, JCMethodDecl tree) { MethodSymbol m = tree.sym; boolean hasTrustMeAnno = m.attribute(syms.trustMeType.tsym) != null; Type varargElemType = null; if (m.isVarArgs()) { varargElemType = types.elemtype(tree.params.last().type); } if (hasTrustMeAnno && !isTrustMeAllowedOnMethod(m)) { if (varargElemType != null) { JCDiagnostic msg = Feature.PRIVATE_SAFE_VARARGS.allowedInSource(source) ? diags.fragment(Fragments.VarargsTrustmeOnVirtualVarargs(m)) : diags.fragment(Fragments.VarargsTrustmeOnVirtualVarargsFinalOnly(m)); log.error(tree, Errors.VarargsInvalidTrustmeAnno(syms.trustMeType.tsym, msg)); } else { log.error(tree, Errors.VarargsInvalidTrustmeAnno(syms.trustMeType.tsym, Fragments.VarargsTrustmeOnNonVarargsMeth(m))); } } else if (hasTrustMeAnno && varargElemType != null && types.isReifiable(varargElemType)) { warnUnsafeVararg(tree, Warnings.VarargsRedundantTrustmeAnno( syms.trustMeType.tsym, diags.fragment(Fragments.VarargsTrustmeOnReifiableVarargs(varargElemType)))); } else if (!hasTrustMeAnno && varargElemType != null && !types.isReifiable(varargElemType)) { warnUnchecked(tree.params.head.pos(), Warnings.UncheckedVarargsNonReifiableType(varargElemType)); } } //where private boolean isTrustMeAllowedOnMethod(Symbol s) { return (s.flags() & VARARGS) != 0 && (s.isConstructor() || (s.flags() & (STATIC | FINAL | (Feature.PRIVATE_SAFE_VARARGS.allowedInSource(source) ? PRIVATE : 0) )) != 0); } Type checkLocalVarType(DiagnosticPosition pos, Type t, Name name) { //check that resulting type is not the null type if (t.hasTag(BOT)) { log.error(pos, Errors.CantInferLocalVarType(name, Fragments.LocalCantInferNull)); return types.createErrorType(t); } else if (t.hasTag(VOID)) { log.error(pos, Errors.CantInferLocalVarType(name, Fragments.LocalCantInferVoid)); return types.createErrorType(t); } //upward project the initializer type return types.upward(t, types.captures(t)); } Type checkMethod(final Type mtype, final Symbol sym, final Env env, final List argtrees, final List argtypes, final boolean useVarargs, InferenceContext inferenceContext) { // System.out.println("call : " + env.tree); // System.out.println("method : " + owntype); // System.out.println("actuals: " + argtypes); if (inferenceContext.free(mtype)) { inferenceContext.addFreeTypeListener(List.of(mtype), solvedContext -> checkMethod(solvedContext.asInstType(mtype), sym, env, argtrees, argtypes, useVarargs, solvedContext)); return mtype; } Type owntype = mtype; List formals = owntype.getParameterTypes(); List nonInferred = sym.type.getParameterTypes(); if (nonInferred.length() != formals.length()) nonInferred = formals; Type last = useVarargs ? formals.last() : null; if (sym.name == names.init && sym.owner == syms.enumSym) { formals = formals.tail.tail; nonInferred = nonInferred.tail.tail; } if ((sym.flags() & ANONCONSTR_BASED) != 0) { formals = formals.tail; nonInferred = nonInferred.tail; } List args = argtrees; if (args != null) { //this is null when type-checking a method reference while (formals.head != last) { JCTree arg = args.head; Warner warn = convertWarner(arg.pos(), arg.type, nonInferred.head); assertConvertible(arg, arg.type, formals.head, warn); args = args.tail; formals = formals.tail; nonInferred = nonInferred.tail; } if (useVarargs) { Type varArg = types.elemtype(last); while (args.tail != null) { JCTree arg = args.head; Warner warn = convertWarner(arg.pos(), arg.type, varArg); assertConvertible(arg, arg.type, varArg, warn); args = args.tail; } } else if ((sym.flags() & (VARARGS | SIGNATURE_POLYMORPHIC)) == VARARGS) { // non-varargs call to varargs method Type varParam = owntype.getParameterTypes().last(); Type lastArg = argtypes.last(); if (types.isSubtypeUnchecked(lastArg, types.elemtype(varParam)) && !types.isSameType(types.erasure(varParam), types.erasure(lastArg))) log.warning(argtrees.last().pos(), Warnings.InexactNonVarargsCall(types.elemtype(varParam),varParam)); } } if (useVarargs) { Type argtype = owntype.getParameterTypes().last(); if (!types.isReifiable(argtype) && (sym.baseSymbol().attribute(syms.trustMeType.tsym) == null || !isTrustMeAllowedOnMethod(sym))) { warnUnchecked(env.tree.pos(), Warnings.UncheckedGenericArrayCreation(argtype)); } TreeInfo.setVarargsElement(env.tree, types.elemtype(argtype)); } return owntype; } //where private void assertConvertible(JCTree tree, Type actual, Type formal, Warner warn) { if (types.isConvertible(actual, formal, warn)) return; if (formal.isCompound() && types.isSubtype(actual, types.supertype(formal)) && types.isSubtypeUnchecked(actual, types.interfaces(formal), warn)) return; } /** * Check that type 't' is a valid instantiation of a generic class * (see JLS 4.5) * * @param t class type to be checked * @return true if 't' is well-formed */ public boolean checkValidGenericType(Type t) { return firstIncompatibleTypeArg(t) == null; } //WHERE private Type firstIncompatibleTypeArg(Type type) { List formals = type.tsym.type.allparams(); List actuals = type.allparams(); List args = type.getTypeArguments(); List forms = type.tsym.type.getTypeArguments(); ListBuffer bounds_buf = new ListBuffer<>(); // For matching pairs of actual argument types `a' and // formal type parameters with declared bound `b' ... while (args.nonEmpty() && forms.nonEmpty()) { // exact type arguments needs to know their // bounds (for upper and lower bound // calculations). So we create new bounds where // type-parameters are replaced with actuals argument types. bounds_buf.append(types.subst(forms.head.getUpperBound(), formals, actuals)); args = args.tail; forms = forms.tail; } args = type.getTypeArguments(); List tvars_cap = types.substBounds(formals, formals, types.capture(type).allparams()); while (args.nonEmpty() && tvars_cap.nonEmpty()) { // Let the actual arguments know their bound args.head.withTypeVar((TypeVar)tvars_cap.head); args = args.tail; tvars_cap = tvars_cap.tail; } args = type.getTypeArguments(); List bounds = bounds_buf.toList(); while (args.nonEmpty() && bounds.nonEmpty()) { Type actual = args.head; if (!isTypeArgErroneous(actual) && !bounds.head.isErroneous() && !checkExtends(actual, bounds.head)) { return args.head; } args = args.tail; bounds = bounds.tail; } args = type.getTypeArguments(); bounds = bounds_buf.toList(); for (Type arg : types.capture(type).getTypeArguments()) { if (arg.hasTag(TYPEVAR) && arg.getUpperBound().isErroneous() && !bounds.head.isErroneous() && !isTypeArgErroneous(args.head)) { return args.head; } bounds = bounds.tail; args = args.tail; } return null; } //where boolean isTypeArgErroneous(Type t) { return isTypeArgErroneous.visit(t); } Types.UnaryVisitor isTypeArgErroneous = new Types.UnaryVisitor() { public Boolean visitType(Type t, Void s) { return t.isErroneous(); } @Override public Boolean visitTypeVar(TypeVar t, Void s) { return visit(t.getUpperBound()); } @Override public Boolean visitCapturedType(CapturedType t, Void s) { return visit(t.getUpperBound()) || visit(t.getLowerBound()); } @Override public Boolean visitWildcardType(WildcardType t, Void s) { return visit(t.type); } }; /** Check that given modifiers are legal for given symbol and * return modifiers together with any implicit modifiers for that symbol. * Warning: we can't use flags() here since this method * is called during class enter, when flags() would cause a premature * completion. * @param pos Position to be used for error reporting. * @param flags The set of modifiers given in a definition. * @param sym The defined symbol. */ long checkFlags(DiagnosticPosition pos, long flags, Symbol sym, JCTree tree) { long mask; long implicit = 0; switch (sym.kind) { case VAR: if (TreeInfo.isReceiverParam(tree)) mask = ReceiverParamFlags; else if (sym.owner.kind != TYP) mask = LocalVarFlags; else if ((sym.owner.flags_field & INTERFACE) != 0) mask = implicit = InterfaceVarFlags; else mask = VarFlags; break; case MTH: if (sym.name == names.init) { if ((sym.owner.flags_field & ENUM) != 0) { // enum constructors cannot be declared public or // protected and must be implicitly or explicitly // private implicit = PRIVATE; mask = PRIVATE; } else mask = ConstructorFlags; } else if ((sym.owner.flags_field & INTERFACE) != 0) { if ((sym.owner.flags_field & ANNOTATION) != 0) { mask = AnnotationTypeElementMask; implicit = PUBLIC | ABSTRACT; } else if ((flags & (DEFAULT | STATIC | PRIVATE)) != 0) { mask = InterfaceMethodMask; implicit = (flags & PRIVATE) != 0 ? 0 : PUBLIC; if ((flags & DEFAULT) != 0) { implicit |= ABSTRACT; } } else { mask = implicit = InterfaceMethodFlags; } } else if ((sym.owner.flags_field & RECORD) != 0) { mask = RecordMethodFlags; } else { mask = MethodFlags; } if ((flags & STRICTFP) != 0) { warnOnExplicitStrictfp(pos); } // Imply STRICTFP if owner has STRICTFP set. if (((flags|implicit) & Flags.ABSTRACT) == 0 || ((flags) & Flags.DEFAULT) != 0) implicit |= sym.owner.flags_field & STRICTFP; break; case TYP: if (sym.owner.kind.matches(KindSelector.VAL_MTH) || (sym.isDirectlyOrIndirectlyLocal() && (flags & ANNOTATION) != 0)) { boolean implicitlyStatic = !sym.isAnonymous() && ((flags & RECORD) != 0 || (flags & ENUM) != 0 || (flags & INTERFACE) != 0); boolean staticOrImplicitlyStatic = (flags & STATIC) != 0 || implicitlyStatic; // local statics are allowed only if records are allowed too mask = staticOrImplicitlyStatic && allowRecords && (flags & ANNOTATION) == 0 ? StaticLocalFlags : LocalClassFlags; implicit = implicitlyStatic ? STATIC : implicit; } else if (sym.owner.kind == TYP) { // statics in inner classes are allowed only if records are allowed too mask = ((flags & STATIC) != 0) && allowRecords && (flags & ANNOTATION) == 0 ? ExtendedMemberStaticClassFlags : ExtendedMemberClassFlags; if (sym.owner.owner.kind == PCK || (sym.owner.flags_field & STATIC) != 0) { mask |= STATIC; } else if (!allowRecords && ((flags & ENUM) != 0 || (flags & RECORD) != 0)) { log.error(pos, Errors.StaticDeclarationNotAllowedInInnerClasses); } // Nested interfaces and enums are always STATIC (Spec ???) if ((flags & (INTERFACE | ENUM | RECORD)) != 0 ) implicit = STATIC; } else { mask = ExtendedClassFlags; } // Interfaces are always ABSTRACT if ((flags & INTERFACE) != 0) implicit |= ABSTRACT; if ((flags & ENUM) != 0) { // enums can't be declared abstract, final, sealed or non-sealed mask &= ~(ABSTRACT | FINAL | SEALED | NON_SEALED); implicit |= implicitEnumFinalFlag(tree); } if ((flags & RECORD) != 0) { // records can't be declared abstract mask &= ~ABSTRACT; implicit |= FINAL; } if ((flags & STRICTFP) != 0) { warnOnExplicitStrictfp(pos); } // Imply STRICTFP if owner has STRICTFP set. implicit |= sym.owner.flags_field & STRICTFP; break; default: throw new AssertionError(); } long illegal = flags & ExtendedStandardFlags & ~mask; if (illegal != 0) { if ((illegal & INTERFACE) != 0) { log.error(pos, ((flags & ANNOTATION) != 0) ? Errors.AnnotationDeclNotAllowedHere : Errors.IntfNotAllowedHere); mask |= INTERFACE; } else { log.error(pos, Errors.ModNotAllowedHere(asFlagSet(illegal))); } } else if ((sym.kind == TYP || // ISSUE: Disallowing abstract&private is no longer appropriate // in the presence of inner classes. Should it be deleted here? checkDisjoint(pos, flags, ABSTRACT, PRIVATE | STATIC | DEFAULT)) && checkDisjoint(pos, flags, STATIC | PRIVATE, DEFAULT) && checkDisjoint(pos, flags, ABSTRACT | INTERFACE, FINAL | NATIVE | SYNCHRONIZED) && checkDisjoint(pos, flags, PUBLIC, PRIVATE | PROTECTED) && checkDisjoint(pos, flags, PRIVATE, PUBLIC | PROTECTED) && checkDisjoint(pos, flags, FINAL, VOLATILE) && (sym.kind == TYP || checkDisjoint(pos, flags, ABSTRACT | NATIVE, STRICTFP)) && checkDisjoint(pos, flags, FINAL, SEALED | NON_SEALED) && checkDisjoint(pos, flags, SEALED, FINAL | NON_SEALED) && checkDisjoint(pos, flags, SEALED, ANNOTATION)) { // skip } return flags & (mask | ~ExtendedStandardFlags) | implicit; } private void warnOnExplicitStrictfp(DiagnosticPosition pos) { DiagnosticPosition prevLintPos = deferredLintHandler.setPos(pos); try { deferredLintHandler.report(() -> { if (lint.isEnabled(LintCategory.STRICTFP)) { log.warning(LintCategory.STRICTFP, pos, Warnings.Strictfp); } }); } finally { deferredLintHandler.setPos(prevLintPos); } } /** Determine if this enum should be implicitly final. * * If the enum has no specialized enum constants, it is final. * * If the enum does have specialized enum constants, it is * not final. */ private long implicitEnumFinalFlag(JCTree tree) { if (!tree.hasTag(CLASSDEF)) return 0; class SpecialTreeVisitor extends JCTree.Visitor { boolean specialized; SpecialTreeVisitor() { this.specialized = false; } @Override public void visitTree(JCTree tree) { /* no-op */ } @Override public void visitVarDef(JCVariableDecl tree) { if ((tree.mods.flags & ENUM) != 0) { if (tree.init instanceof JCNewClass newClass && newClass.def != null) { specialized = true; } } } } SpecialTreeVisitor sts = new SpecialTreeVisitor(); JCClassDecl cdef = (JCClassDecl) tree; for (JCTree defs: cdef.defs) { defs.accept(sts); if (sts.specialized) return allowSealed ? SEALED : 0; } return FINAL; } /* ************************************************************************* * Type Validation **************************************************************************/ /** Validate a type expression. That is, * check that all type arguments of a parametric type are within * their bounds. This must be done in a second phase after type attribution * since a class might have a subclass as type parameter bound. E.g: * *

{@code
     *  class B { ... }
     *  class C extends B { ... }
     *  }
* * and we can't make sure that the bound is already attributed because * of possible cycles. * * Visitor method: Validate a type expression, if it is not null, catching * and reporting any completion failures. */ void validate(JCTree tree, Env env) { validate(tree, env, true); } void validate(JCTree tree, Env env, boolean checkRaw) { new Validator(env).validateTree(tree, checkRaw, true); } /** Visitor method: Validate a list of type expressions. */ void validate(List trees, Env env) { for (List l = trees; l.nonEmpty(); l = l.tail) validate(l.head, env); } /** A visitor class for type validation. */ class Validator extends JCTree.Visitor { boolean checkRaw; boolean isOuter; Env env; Validator(Env env) { this.env = env; } @Override public void visitTypeArray(JCArrayTypeTree tree) { validateTree(tree.elemtype, checkRaw, isOuter); } @Override public void visitTypeApply(JCTypeApply tree) { if (tree.type.hasTag(CLASS)) { List args = tree.arguments; List forms = tree.type.tsym.type.getTypeArguments(); Type incompatibleArg = firstIncompatibleTypeArg(tree.type); if (incompatibleArg != null) { for (JCTree arg : tree.arguments) { if (arg.type == incompatibleArg) { log.error(arg, Errors.NotWithinBounds(incompatibleArg, forms.head)); } forms = forms.tail; } } forms = tree.type.tsym.type.getTypeArguments(); boolean is_java_lang_Class = tree.type.tsym.flatName() == names.java_lang_Class; // For matching pairs of actual argument types `a' and // formal type parameters with declared bound `b' ... while (args.nonEmpty() && forms.nonEmpty()) { validateTree(args.head, !(isOuter && is_java_lang_Class), false); args = args.tail; forms = forms.tail; } // Check that this type is either fully parameterized, or // not parameterized at all. if (tree.type.getEnclosingType().isRaw()) log.error(tree.pos(), Errors.ImproperlyFormedTypeInnerRawParam); if (tree.clazz.hasTag(SELECT)) visitSelectInternal((JCFieldAccess)tree.clazz); } } @Override public void visitTypeParameter(JCTypeParameter tree) { validateTrees(tree.bounds, true, isOuter); checkClassBounds(tree.pos(), tree.type); } @Override public void visitWildcard(JCWildcard tree) { if (tree.inner != null) validateTree(tree.inner, true, isOuter); } @Override public void visitSelect(JCFieldAccess tree) { if (tree.type.hasTag(CLASS)) { visitSelectInternal(tree); // Check that this type is either fully parameterized, or // not parameterized at all. if (tree.selected.type.isParameterized() && tree.type.tsym.type.getTypeArguments().nonEmpty()) log.error(tree.pos(), Errors.ImproperlyFormedTypeParamMissing); } } public void visitSelectInternal(JCFieldAccess tree) { if (tree.type.tsym.isStatic() && tree.selected.type.isParameterized()) { // The enclosing type is not a class, so we are // looking at a static member type. However, the // qualifying expression is parameterized. log.error(tree.pos(), Errors.CantSelectStaticClassFromParamType); } else { // otherwise validate the rest of the expression tree.selected.accept(this); } } @Override public void visitAnnotatedType(JCAnnotatedType tree) { tree.underlyingType.accept(this); } @Override public void visitTypeIdent(JCPrimitiveTypeTree that) { if (that.type.hasTag(TypeTag.VOID)) { log.error(that.pos(), Errors.VoidNotAllowedHere); } super.visitTypeIdent(that); } /** Default visitor method: do nothing. */ @Override public void visitTree(JCTree tree) { } public void validateTree(JCTree tree, boolean checkRaw, boolean isOuter) { if (tree != null) { boolean prevCheckRaw = this.checkRaw; this.checkRaw = checkRaw; this.isOuter = isOuter; try { tree.accept(this); if (checkRaw) checkRaw(tree, env); } catch (CompletionFailure ex) { completionError(tree.pos(), ex); } finally { this.checkRaw = prevCheckRaw; } } } public void validateTrees(List trees, boolean checkRaw, boolean isOuter) { for (List l = trees; l.nonEmpty(); l = l.tail) validateTree(l.head, checkRaw, isOuter); } } void checkRaw(JCTree tree, Env env) { if (lint.isEnabled(LintCategory.RAW) && tree.type.hasTag(CLASS) && !TreeInfo.isDiamond(tree) && !withinAnonConstr(env) && tree.type.isRaw()) { log.warning(LintCategory.RAW, tree.pos(), Warnings.RawClassUse(tree.type, tree.type.tsym.type)); } } //where private boolean withinAnonConstr(Env env) { return env.enclClass.name.isEmpty() && env.enclMethod != null && env.enclMethod.name == names.init; } /* ************************************************************************* * Exception checking **************************************************************************/ /* The following methods treat classes as sets that contain * the class itself and all their subclasses */ /** Is given type a subtype of some of the types in given list? */ boolean subset(Type t, List ts) { for (List l = ts; l.nonEmpty(); l = l.tail) if (types.isSubtype(t, l.head)) return true; return false; } /** Is given type a subtype or supertype of * some of the types in given list? */ boolean intersects(Type t, List ts) { for (List l = ts; l.nonEmpty(); l = l.tail) if (types.isSubtype(t, l.head) || types.isSubtype(l.head, t)) return true; return false; } /** Add type set to given type list, unless it is a subclass of some class * in the list. */ List incl(Type t, List ts) { return subset(t, ts) ? ts : excl(t, ts).prepend(t); } /** Remove type set from type set list. */ List excl(Type t, List ts) { if (ts.isEmpty()) { return ts; } else { List ts1 = excl(t, ts.tail); if (types.isSubtype(ts.head, t)) return ts1; else if (ts1 == ts.tail) return ts; else return ts1.prepend(ts.head); } } /** Form the union of two type set lists. */ List union(List ts1, List ts2) { List ts = ts1; for (List l = ts2; l.nonEmpty(); l = l.tail) ts = incl(l.head, ts); return ts; } /** Form the difference of two type lists. */ List diff(List ts1, List ts2) { List ts = ts1; for (List l = ts2; l.nonEmpty(); l = l.tail) ts = excl(l.head, ts); return ts; } /** Form the intersection of two type lists. */ public List intersect(List ts1, List ts2) { List ts = List.nil(); for (List l = ts1; l.nonEmpty(); l = l.tail) if (subset(l.head, ts2)) ts = incl(l.head, ts); for (List l = ts2; l.nonEmpty(); l = l.tail) if (subset(l.head, ts1)) ts = incl(l.head, ts); return ts; } /** Is exc an exception symbol that need not be declared? */ boolean isUnchecked(ClassSymbol exc) { return exc.kind == ERR || exc.isSubClass(syms.errorType.tsym, types) || exc.isSubClass(syms.runtimeExceptionType.tsym, types); } /** Is exc an exception type that need not be declared? */ boolean isUnchecked(Type exc) { return (exc.hasTag(TYPEVAR)) ? isUnchecked(types.supertype(exc)) : (exc.hasTag(CLASS)) ? isUnchecked((ClassSymbol)exc.tsym) : exc.hasTag(BOT); } boolean isChecked(Type exc) { return !isUnchecked(exc); } /** Same, but handling completion failures. */ boolean isUnchecked(DiagnosticPosition pos, Type exc) { try { return isUnchecked(exc); } catch (CompletionFailure ex) { completionError(pos, ex); return true; } } /** Is exc handled by given exception list? */ boolean isHandled(Type exc, List handled) { return isUnchecked(exc) || subset(exc, handled); } /** Return all exceptions in thrown list that are not in handled list. * @param thrown The list of thrown exceptions. * @param handled The list of handled exceptions. */ List unhandled(List thrown, List handled) { List unhandled = List.nil(); for (List l = thrown; l.nonEmpty(); l = l.tail) if (!isHandled(l.head, handled)) unhandled = unhandled.prepend(l.head); return unhandled; } /* ************************************************************************* * Overriding/Implementation checking **************************************************************************/ /** The level of access protection given by a flag set, * where PRIVATE is highest and PUBLIC is lowest. */ static int protection(long flags) { switch ((short)(flags & AccessFlags)) { case PRIVATE: return 3; case PROTECTED: return 1; default: case PUBLIC: return 0; case 0: return 2; } } /** A customized "cannot override" error message. * @param m The overriding method. * @param other The overridden method. * @return An internationalized string. */ Fragment cannotOverride(MethodSymbol m, MethodSymbol other) { Symbol mloc = m.location(); Symbol oloc = other.location(); if ((other.owner.flags() & INTERFACE) == 0) return Fragments.CantOverride(m, mloc, other, oloc); else if ((m.owner.flags() & INTERFACE) == 0) return Fragments.CantImplement(m, mloc, other, oloc); else return Fragments.ClashesWith(m, mloc, other, oloc); } /** A customized "override" warning message. * @param m The overriding method. * @param other The overridden method. * @return An internationalized string. */ Fragment uncheckedOverrides(MethodSymbol m, MethodSymbol other) { Symbol mloc = m.location(); Symbol oloc = other.location(); if ((other.owner.flags() & INTERFACE) == 0) return Fragments.UncheckedOverride(m, mloc, other, oloc); else if ((m.owner.flags() & INTERFACE) == 0) return Fragments.UncheckedImplement(m, mloc, other, oloc); else return Fragments.UncheckedClashWith(m, mloc, other, oloc); } /** A customized "override" warning message. * @param m The overriding method. * @param other The overridden method. * @return An internationalized string. */ Fragment varargsOverrides(MethodSymbol m, MethodSymbol other) { Symbol mloc = m.location(); Symbol oloc = other.location(); if ((other.owner.flags() & INTERFACE) == 0) return Fragments.VarargsOverride(m, mloc, other, oloc); else if ((m.owner.flags() & INTERFACE) == 0) return Fragments.VarargsImplement(m, mloc, other, oloc); else return Fragments.VarargsClashWith(m, mloc, other, oloc); } /** Check that this method conforms with overridden method 'other'. * where `origin' is the class where checking started. * Complications: * (1) Do not check overriding of synthetic methods * (reason: they might be final). * todo: check whether this is still necessary. * (2) Admit the case where an interface proxy throws fewer exceptions * than the method it implements. Augment the proxy methods with the * undeclared exceptions in this case. * (3) When generics are enabled, admit the case where an interface proxy * has a result type * extended by the result type of the method it implements. * Change the proxies result type to the smaller type in this case. * * @param tree The tree from which positions * are extracted for errors. * @param m The overriding method. * @param other The overridden method. * @param origin The class of which the overriding method * is a member. */ void checkOverride(JCTree tree, MethodSymbol m, MethodSymbol other, ClassSymbol origin) { // Don't check overriding of synthetic methods or by bridge methods. if ((m.flags() & (SYNTHETIC|BRIDGE)) != 0 || (other.flags() & SYNTHETIC) != 0) { return; } // Error if static method overrides instance method (JLS 8.4.8.2). if ((m.flags() & STATIC) != 0 && (other.flags() & STATIC) == 0) { log.error(TreeInfo.diagnosticPositionFor(m, tree), Errors.OverrideStatic(cannotOverride(m, other))); m.flags_field |= BAD_OVERRIDE; return; } // Error if instance method overrides static or final // method (JLS 8.4.8.1). if ((other.flags() & FINAL) != 0 || (m.flags() & STATIC) == 0 && (other.flags() & STATIC) != 0) { log.error(TreeInfo.diagnosticPositionFor(m, tree), Errors.OverrideMeth(cannotOverride(m, other), asFlagSet(other.flags() & (FINAL | STATIC)))); m.flags_field |= BAD_OVERRIDE; return; } if ((m.owner.flags() & ANNOTATION) != 0) { // handled in validateAnnotationMethod return; } // Error if overriding method has weaker access (JLS 8.4.8.3). if (protection(m.flags()) > protection(other.flags())) { log.error(TreeInfo.diagnosticPositionFor(m, tree), (other.flags() & AccessFlags) == 0 ? Errors.OverrideWeakerAccess(cannotOverride(m, other), "package") : Errors.OverrideWeakerAccess(cannotOverride(m, other), asFlagSet(other.flags() & AccessFlags))); m.flags_field |= BAD_OVERRIDE; return; } if (shouldCheckPreview(m, other, origin)) { checkPreview(tree.pos(), m, other); } Type mt = types.memberType(origin.type, m); Type ot = types.memberType(origin.type, other); // Error if overriding result type is different // (or, in the case of generics mode, not a subtype) of // overridden result type. We have to rename any type parameters // before comparing types. List mtvars = mt.getTypeArguments(); List otvars = ot.getTypeArguments(); Type mtres = mt.getReturnType(); Type otres = types.subst(ot.getReturnType(), otvars, mtvars); overrideWarner.clear(); boolean resultTypesOK = types.returnTypeSubstitutable(mt, ot, otres, overrideWarner); if (!resultTypesOK) { if ((m.flags() & STATIC) != 0 && (other.flags() & STATIC) != 0) { log.error(TreeInfo.diagnosticPositionFor(m, tree), Errors.OverrideIncompatibleRet(Fragments.CantHide(m, m.location(), other, other.location()), mtres, otres)); m.flags_field |= BAD_OVERRIDE; } else { log.error(TreeInfo.diagnosticPositionFor(m, tree), Errors.OverrideIncompatibleRet(cannotOverride(m, other), mtres, otres)); m.flags_field |= BAD_OVERRIDE; } return; } else if (overrideWarner.hasNonSilentLint(LintCategory.UNCHECKED)) { warnUnchecked(TreeInfo.diagnosticPositionFor(m, tree), Warnings.OverrideUncheckedRet(uncheckedOverrides(m, other), mtres, otres)); } // Error if overriding method throws an exception not reported // by overridden method. List otthrown = types.subst(ot.getThrownTypes(), otvars, mtvars); List unhandledErased = unhandled(mt.getThrownTypes(), types.erasure(otthrown)); List unhandledUnerased = unhandled(mt.getThrownTypes(), otthrown); if (unhandledErased.nonEmpty()) { log.error(TreeInfo.diagnosticPositionFor(m, tree), Errors.OverrideMethDoesntThrow(cannotOverride(m, other), unhandledUnerased.head)); m.flags_field |= BAD_OVERRIDE; return; } else if (unhandledUnerased.nonEmpty()) { warnUnchecked(TreeInfo.diagnosticPositionFor(m, tree), Warnings.OverrideUncheckedThrown(cannotOverride(m, other), unhandledUnerased.head)); return; } // Optional warning if varargs don't agree if ((((m.flags() ^ other.flags()) & Flags.VARARGS) != 0) && lint.isEnabled(LintCategory.OVERRIDES)) { log.warning(TreeInfo.diagnosticPositionFor(m, tree), ((m.flags() & Flags.VARARGS) != 0) ? Warnings.OverrideVarargsMissing(varargsOverrides(m, other)) : Warnings.OverrideVarargsExtra(varargsOverrides(m, other))); } // Warn if instance method overrides bridge method (compiler spec ??) if ((other.flags() & BRIDGE) != 0) { log.warning(TreeInfo.diagnosticPositionFor(m, tree), Warnings.OverrideBridge(uncheckedOverrides(m, other))); } // Warn if a deprecated method overridden by a non-deprecated one. if (!isDeprecatedOverrideIgnorable(other, origin)) { Lint prevLint = setLint(lint.augment(m)); try { checkDeprecated(() -> TreeInfo.diagnosticPositionFor(m, tree), m, other); } finally { setLint(prevLint); } } } // where private boolean shouldCheckPreview(MethodSymbol m, MethodSymbol other, ClassSymbol origin) { if (m.owner != origin || //performance - only do the expensive checks when the overridden method is a Preview API: (other.flags() & PREVIEW_API) == 0) { return false; } for (Symbol s : types.membersClosure(origin.type, false).getSymbolsByName(m.name)) { if (m != s && m.overrides(s, origin, types, false)) { //only produce preview warnings or errors if "m" immediatelly overrides "other" //without intermediate overriding methods: return s == other; } } return false; } private boolean isDeprecatedOverrideIgnorable(MethodSymbol m, ClassSymbol origin) { // If the method, m, is defined in an interface, then ignore the issue if the method // is only inherited via a supertype and also implemented in the supertype, // because in that case, we will rediscover the issue when examining the method // in the supertype. // If the method, m, is not defined in an interface, then the only time we need to // address the issue is when the method is the supertype implementation: any other // case, we will have dealt with when examining the supertype classes ClassSymbol mc = m.enclClass(); Type st = types.supertype(origin.type); if (!st.hasTag(CLASS)) return true; MethodSymbol stimpl = m.implementation((ClassSymbol)st.tsym, types, false); if (mc != null && ((mc.flags() & INTERFACE) != 0)) { List intfs = types.interfaces(origin.type); return (intfs.contains(mc.type) ? false : (stimpl != null)); } else return (stimpl != m); } // used to check if there were any unchecked conversions Warner overrideWarner = new Warner(); /** Check that a class does not inherit two concrete methods * with the same signature. * @param pos Position to be used for error reporting. * @param site The class type to be checked. */ public void checkCompatibleConcretes(DiagnosticPosition pos, Type site) { Type sup = types.supertype(site); if (!sup.hasTag(CLASS)) return; for (Type t1 = sup; t1.hasTag(CLASS) && t1.tsym.type.isParameterized(); t1 = types.supertype(t1)) { for (Symbol s1 : t1.tsym.members().getSymbols(NON_RECURSIVE)) { if (s1.kind != MTH || (s1.flags() & (STATIC|SYNTHETIC|BRIDGE)) != 0 || !s1.isInheritedIn(site.tsym, types) || ((MethodSymbol)s1).implementation(site.tsym, types, true) != s1) continue; Type st1 = types.memberType(t1, s1); int s1ArgsLength = st1.getParameterTypes().length(); if (st1 == s1.type) continue; for (Type t2 = sup; t2.hasTag(CLASS); t2 = types.supertype(t2)) { for (Symbol s2 : t2.tsym.members().getSymbolsByName(s1.name)) { if (s2 == s1 || s2.kind != MTH || (s2.flags() & (STATIC|SYNTHETIC|BRIDGE)) != 0 || s2.type.getParameterTypes().length() != s1ArgsLength || !s2.isInheritedIn(site.tsym, types) || ((MethodSymbol)s2).implementation(site.tsym, types, true) != s2) continue; Type st2 = types.memberType(t2, s2); if (types.overrideEquivalent(st1, st2)) log.error(pos, Errors.ConcreteInheritanceConflict(s1, t1, s2, t2, sup)); } } } } } /** Check that classes (or interfaces) do not each define an abstract * method with same name and arguments but incompatible return types. * @param pos Position to be used for error reporting. * @param t1 The first argument type. * @param t2 The second argument type. */ public boolean checkCompatibleAbstracts(DiagnosticPosition pos, Type t1, Type t2, Type site) { if ((site.tsym.flags() & COMPOUND) != 0) { // special case for intersections: need to eliminate wildcards in supertypes t1 = types.capture(t1); t2 = types.capture(t2); } return firstIncompatibility(pos, t1, t2, site) == null; } /** Return the first method which is defined with same args * but different return types in two given interfaces, or null if none * exists. * @param t1 The first type. * @param t2 The second type. * @param site The most derived type. * @return symbol from t2 that conflicts with one in t1. */ private Symbol firstIncompatibility(DiagnosticPosition pos, Type t1, Type t2, Type site) { Map interfaces1 = new HashMap<>(); closure(t1, interfaces1); Map interfaces2; if (t1 == t2) interfaces2 = interfaces1; else closure(t2, interfaces1, interfaces2 = new HashMap<>()); for (Type t3 : interfaces1.values()) { for (Type t4 : interfaces2.values()) { Symbol s = firstDirectIncompatibility(pos, t3, t4, site); if (s != null) return s; } } return null; } /** Compute all the supertypes of t, indexed by type symbol. */ private void closure(Type t, Map typeMap) { if (!t.hasTag(CLASS)) return; if (typeMap.put(t.tsym, t) == null) { closure(types.supertype(t), typeMap); for (Type i : types.interfaces(t)) closure(i, typeMap); } } /** Compute all the supertypes of t, indexed by type symbol (except those in typesSkip). */ private void closure(Type t, Map typesSkip, Map typeMap) { if (!t.hasTag(CLASS)) return; if (typesSkip.get(t.tsym) != null) return; if (typeMap.put(t.tsym, t) == null) { closure(types.supertype(t), typesSkip, typeMap); for (Type i : types.interfaces(t)) closure(i, typesSkip, typeMap); } } /** Return the first method in t2 that conflicts with a method from t1. */ private Symbol firstDirectIncompatibility(DiagnosticPosition pos, Type t1, Type t2, Type site) { for (Symbol s1 : t1.tsym.members().getSymbols(NON_RECURSIVE)) { Type st1 = null; if (s1.kind != MTH || !s1.isInheritedIn(site.tsym, types) || (s1.flags() & SYNTHETIC) != 0) continue; Symbol impl = ((MethodSymbol)s1).implementation(site.tsym, types, false); if (impl != null && (impl.flags() & ABSTRACT) == 0) continue; for (Symbol s2 : t2.tsym.members().getSymbolsByName(s1.name)) { if (s1 == s2) continue; if (s2.kind != MTH || !s2.isInheritedIn(site.tsym, types) || (s2.flags() & SYNTHETIC) != 0) continue; if (st1 == null) st1 = types.memberType(t1, s1); Type st2 = types.memberType(t2, s2); if (types.overrideEquivalent(st1, st2)) { List tvars1 = st1.getTypeArguments(); List tvars2 = st2.getTypeArguments(); Type rt1 = st1.getReturnType(); Type rt2 = types.subst(st2.getReturnType(), tvars2, tvars1); boolean compat = types.isSameType(rt1, rt2) || !rt1.isPrimitiveOrVoid() && !rt2.isPrimitiveOrVoid() && (types.covariantReturnType(rt1, rt2, types.noWarnings) || types.covariantReturnType(rt2, rt1, types.noWarnings)) || checkCommonOverriderIn(s1,s2,site); if (!compat) { log.error(pos, Errors.TypesIncompatible(t1, t2, Fragments.IncompatibleDiffRet(s2.name, types.memberType(t2, s2).getParameterTypes()))); return s2; } } else if (checkNameClash((ClassSymbol)site.tsym, s1, s2) && !checkCommonOverriderIn(s1, s2, site)) { log.error(pos, Errors.NameClashSameErasureNoOverride( s1.name, types.memberType(site, s1).asMethodType().getParameterTypes(), s1.location(), s2.name, types.memberType(site, s2).asMethodType().getParameterTypes(), s2.location())); return s2; } } } return null; } //WHERE boolean checkCommonOverriderIn(Symbol s1, Symbol s2, Type site) { Map supertypes = new HashMap<>(); Type st1 = types.memberType(site, s1); Type st2 = types.memberType(site, s2); closure(site, supertypes); for (Type t : supertypes.values()) { for (Symbol s3 : t.tsym.members().getSymbolsByName(s1.name)) { if (s3 == s1 || s3 == s2 || s3.kind != MTH || (s3.flags() & (BRIDGE|SYNTHETIC)) != 0) continue; Type st3 = types.memberType(site,s3); if (types.overrideEquivalent(st3, st1) && types.overrideEquivalent(st3, st2) && types.returnTypeSubstitutable(st3, st1) && types.returnTypeSubstitutable(st3, st2)) { return true; } } } return false; } /** Check that a given method conforms with any method it overrides. * @param tree The tree from which positions are extracted * for errors. * @param m The overriding method. */ void checkOverride(Env env, JCMethodDecl tree, MethodSymbol m) { ClassSymbol origin = (ClassSymbol)m.owner; if ((origin.flags() & ENUM) != 0 && names.finalize.equals(m.name)) { if (m.overrides(syms.enumFinalFinalize, origin, types, false)) { log.error(tree.pos(), Errors.EnumNoFinalize); return; } } if (allowRecords && origin.isRecord()) { // let's find out if this is a user defined accessor in which case the @Override annotation is acceptable Optional recordComponent = origin.getRecordComponents().stream() .filter(rc -> rc.accessor == tree.sym && (rc.accessor.flags_field & GENERATED_MEMBER) == 0).findFirst(); if (recordComponent.isPresent()) { return; } } for (Type t = origin.type; t.hasTag(CLASS); t = types.supertype(t)) { if (t != origin.type) { checkOverride(tree, t, origin, m); } for (Type t2 : types.interfaces(t)) { checkOverride(tree, t2, origin, m); } } final boolean explicitOverride = m.attribute(syms.overrideType.tsym) != null; // Check if this method must override a super method due to being annotated with @Override // or by virtue of being a member of a diamond inferred anonymous class. Latter case is to // be treated "as if as they were annotated" with @Override. boolean mustOverride = explicitOverride || (env.info.isAnonymousDiamond && !m.isConstructor() && !m.isPrivate()); if (mustOverride && !isOverrider(m)) { DiagnosticPosition pos = tree.pos(); for (JCAnnotation a : tree.getModifiers().annotations) { if (a.annotationType.type.tsym == syms.overrideType.tsym) { pos = a.pos(); break; } } log.error(pos, explicitOverride ? (m.isStatic() ? Errors.StaticMethodsCannotBeAnnotatedWithOverride : Errors.MethodDoesNotOverrideSuperclass) : Errors.AnonymousDiamondMethodDoesNotOverrideSuperclass(Fragments.DiamondAnonymousMethodsImplicitlyOverride)); } } void checkOverride(JCTree tree, Type site, ClassSymbol origin, MethodSymbol m) { TypeSymbol c = site.tsym; for (Symbol sym : c.members().getSymbolsByName(m.name)) { if (m.overrides(sym, origin, types, false)) { if ((sym.flags() & ABSTRACT) == 0) { checkOverride(tree, m, (MethodSymbol)sym, origin); } } } } private Predicate equalsHasCodeFilter = s -> MethodSymbol.implementation_filter.test(s) && (s.flags() & BAD_OVERRIDE) == 0; public void checkClassOverrideEqualsAndHashIfNeeded(DiagnosticPosition pos, ClassSymbol someClass) { /* At present, annotations cannot possibly have a method that is override * equivalent with Object.equals(Object) but in any case the condition is * fine for completeness. */ if (someClass == (ClassSymbol)syms.objectType.tsym || someClass.isInterface() || someClass.isEnum() || (someClass.flags() & ANNOTATION) != 0 || (someClass.flags() & ABSTRACT) != 0) return; //anonymous inner classes implementing interfaces need especial treatment if (someClass.isAnonymous()) { List interfaces = types.interfaces(someClass.type); if (interfaces != null && !interfaces.isEmpty() && interfaces.head.tsym == syms.comparatorType.tsym) return; } checkClassOverrideEqualsAndHash(pos, someClass); } private void checkClassOverrideEqualsAndHash(DiagnosticPosition pos, ClassSymbol someClass) { if (lint.isEnabled(LintCategory.OVERRIDES)) { MethodSymbol equalsAtObject = (MethodSymbol)syms.objectType .tsym.members().findFirst(names.equals); MethodSymbol hashCodeAtObject = (MethodSymbol)syms.objectType .tsym.members().findFirst(names.hashCode); MethodSymbol equalsImpl = types.implementation(equalsAtObject, someClass, false, equalsHasCodeFilter); boolean overridesEquals = equalsImpl != null && equalsImpl.owner == someClass; boolean overridesHashCode = types.implementation(hashCodeAtObject, someClass, false, equalsHasCodeFilter) != hashCodeAtObject; if (overridesEquals && !overridesHashCode) { log.warning(LintCategory.OVERRIDES, pos, Warnings.OverrideEqualsButNotHashcode(someClass)); } } } public void checkModuleName (JCModuleDecl tree) { Name moduleName = tree.sym.name; Assert.checkNonNull(moduleName); if (lint.isEnabled(LintCategory.MODULE)) { JCExpression qualId = tree.qualId; while (qualId != null) { Name componentName; DiagnosticPosition pos; switch (qualId.getTag()) { case SELECT: JCFieldAccess selectNode = ((JCFieldAccess) qualId); componentName = selectNode.name; pos = selectNode.pos(); qualId = selectNode.selected; break; case IDENT: componentName = ((JCIdent) qualId).name; pos = qualId.pos(); qualId = null; break; default: throw new AssertionError("Unexpected qualified identifier: " + qualId.toString()); } if (componentName != null) { String moduleNameComponentString = componentName.toString(); int nameLength = moduleNameComponentString.length(); if (nameLength > 0 && Character.isDigit(moduleNameComponentString.charAt(nameLength - 1))) { log.warning(Lint.LintCategory.MODULE, pos, Warnings.PoorChoiceForModuleName(componentName)); } } } } } private boolean checkNameClash(ClassSymbol origin, Symbol s1, Symbol s2) { ClashFilter cf = new ClashFilter(origin.type); return (cf.test(s1) && cf.test(s2) && types.hasSameArgs(s1.erasure(types), s2.erasure(types))); } /** Check that all abstract members of given class have definitions. * @param pos Position to be used for error reporting. * @param c The class. */ void checkAllDefined(DiagnosticPosition pos, ClassSymbol c) { MethodSymbol undef = types.firstUnimplementedAbstract(c); if (undef != null) { MethodSymbol undef1 = new MethodSymbol(undef.flags(), undef.name, types.memberType(c.type, undef), undef.owner); log.error(pos, Errors.DoesNotOverrideAbstract(c, undef1, undef1.location())); } } void checkNonCyclicDecl(JCClassDecl tree) { CycleChecker cc = new CycleChecker(); cc.scan(tree); if (!cc.errorFound && !cc.partialCheck) { tree.sym.flags_field |= ACYCLIC; } } class CycleChecker extends TreeScanner { Set seenClasses = new HashSet<>(); boolean errorFound = false; boolean partialCheck = false; private void checkSymbol(DiagnosticPosition pos, Symbol sym) { if (sym != null && sym.kind == TYP) { Env classEnv = enter.getEnv((TypeSymbol)sym); if (classEnv != null) { DiagnosticSource prevSource = log.currentSource(); try { log.useSource(classEnv.toplevel.sourcefile); scan(classEnv.tree); } finally { log.useSource(prevSource.getFile()); } } else if (sym.kind == TYP) { checkClass(pos, sym, List.nil()); } } else if (sym == null || sym.kind != PCK) { //not completed yet partialCheck = true; } } @Override public void visitSelect(JCFieldAccess tree) { super.visitSelect(tree); checkSymbol(tree.pos(), tree.sym); } @Override public void visitIdent(JCIdent tree) { checkSymbol(tree.pos(), tree.sym); } @Override public void visitTypeApply(JCTypeApply tree) { scan(tree.clazz); } @Override public void visitTypeArray(JCArrayTypeTree tree) { scan(tree.elemtype); } @Override public void visitClassDef(JCClassDecl tree) { List supertypes = List.nil(); if (tree.getExtendsClause() != null) { supertypes = supertypes.prepend(tree.getExtendsClause()); } if (tree.getImplementsClause() != null) { for (JCTree intf : tree.getImplementsClause()) { supertypes = supertypes.prepend(intf); } } checkClass(tree.pos(), tree.sym, supertypes); } void checkClass(DiagnosticPosition pos, Symbol c, List supertypes) { if ((c.flags_field & ACYCLIC) != 0) return; if (seenClasses.contains(c)) { errorFound = true; noteCyclic(pos, (ClassSymbol)c); } else if (!c.type.isErroneous()) { try { seenClasses.add(c); if (c.type.hasTag(CLASS)) { if (supertypes.nonEmpty()) { scan(supertypes); } else { ClassType ct = (ClassType)c.type; if (ct.supertype_field == null || ct.interfaces_field == null) { //not completed yet partialCheck = true; return; } checkSymbol(pos, ct.supertype_field.tsym); for (Type intf : ct.interfaces_field) { checkSymbol(pos, intf.tsym); } } if (c.owner.kind == TYP) { checkSymbol(pos, c.owner); } } } finally { seenClasses.remove(c); } } } } /** Check for cyclic references. Issue an error if the * symbol of the type referred to has a LOCKED flag set. * * @param pos Position to be used for error reporting. * @param t The type referred to. */ void checkNonCyclic(DiagnosticPosition pos, Type t) { checkNonCyclicInternal(pos, t); } void checkNonCyclic(DiagnosticPosition pos, TypeVar t) { checkNonCyclic1(pos, t, List.nil()); } private void checkNonCyclic1(DiagnosticPosition pos, Type t, List seen) { final TypeVar tv; if (t.hasTag(TYPEVAR) && (t.tsym.flags() & UNATTRIBUTED) != 0) return; if (seen.contains(t)) { tv = (TypeVar)t; tv.setUpperBound(types.createErrorType(t)); log.error(pos, Errors.CyclicInheritance(t)); } else if (t.hasTag(TYPEVAR)) { tv = (TypeVar)t; seen = seen.prepend(tv); for (Type b : types.getBounds(tv)) checkNonCyclic1(pos, b, seen); } } /** Check for cyclic references. Issue an error if the * symbol of the type referred to has a LOCKED flag set. * * @param pos Position to be used for error reporting. * @param t The type referred to. * @returns True if the check completed on all attributed classes */ private boolean checkNonCyclicInternal(DiagnosticPosition pos, Type t) { boolean complete = true; // was the check complete? //- System.err.println("checkNonCyclicInternal("+t+");");//DEBUG Symbol c = t.tsym; if ((c.flags_field & ACYCLIC) != 0) return true; if ((c.flags_field & LOCKED) != 0) { noteCyclic(pos, (ClassSymbol)c); } else if (!c.type.isErroneous()) { try { c.flags_field |= LOCKED; if (c.type.hasTag(CLASS)) { ClassType clazz = (ClassType)c.type; if (clazz.interfaces_field != null) for (List l=clazz.interfaces_field; l.nonEmpty(); l=l.tail) complete &= checkNonCyclicInternal(pos, l.head); if (clazz.supertype_field != null) { Type st = clazz.supertype_field; if (st != null && st.hasTag(CLASS)) complete &= checkNonCyclicInternal(pos, st); } if (c.owner.kind == TYP) complete &= checkNonCyclicInternal(pos, c.owner.type); } } finally { c.flags_field &= ~LOCKED; } } if (complete) complete = ((c.flags_field & UNATTRIBUTED) == 0) && c.isCompleted(); if (complete) c.flags_field |= ACYCLIC; return complete; } /** Note that we found an inheritance cycle. */ private void noteCyclic(DiagnosticPosition pos, ClassSymbol c) { log.error(pos, Errors.CyclicInheritance(c)); for (List l=types.interfaces(c.type); l.nonEmpty(); l=l.tail) l.head = types.createErrorType((ClassSymbol)l.head.tsym, Type.noType); Type st = types.supertype(c.type); if (st.hasTag(CLASS)) ((ClassType)c.type).supertype_field = types.createErrorType((ClassSymbol)st.tsym, Type.noType); c.type = types.createErrorType(c, c.type); c.flags_field |= ACYCLIC; } /** Check that all methods which implement some * method conform to the method they implement. * @param tree The class definition whose members are checked. */ void checkImplementations(JCClassDecl tree) { checkImplementations(tree, tree.sym, tree.sym); } //where /** Check that all methods which implement some * method in `ic' conform to the method they implement. */ void checkImplementations(JCTree tree, ClassSymbol origin, ClassSymbol ic) { for (List l = types.closure(ic.type); l.nonEmpty(); l = l.tail) { ClassSymbol lc = (ClassSymbol)l.head.tsym; if ((lc.flags() & ABSTRACT) != 0) { for (Symbol sym : lc.members().getSymbols(NON_RECURSIVE)) { if (sym.kind == MTH && (sym.flags() & (STATIC|ABSTRACT)) == ABSTRACT) { MethodSymbol absmeth = (MethodSymbol)sym; MethodSymbol implmeth = absmeth.implementation(origin, types, false); if (implmeth != null && implmeth != absmeth && (implmeth.owner.flags() & INTERFACE) == (origin.flags() & INTERFACE)) { // don't check if implmeth is in a class, yet // origin is an interface. This case arises only // if implmeth is declared in Object. The reason is // that interfaces really don't inherit from // Object it's just that the compiler represents // things that way. checkOverride(tree, implmeth, absmeth, origin); } } } } } } /** Check that all abstract methods implemented by a class are * mutually compatible. * @param pos Position to be used for error reporting. * @param c The class whose interfaces are checked. */ void checkCompatibleSupertypes(DiagnosticPosition pos, Type c) { List supertypes = types.interfaces(c); Type supertype = types.supertype(c); if (supertype.hasTag(CLASS) && (supertype.tsym.flags() & ABSTRACT) != 0) supertypes = supertypes.prepend(supertype); for (List l = supertypes; l.nonEmpty(); l = l.tail) { if (!l.head.getTypeArguments().isEmpty() && !checkCompatibleAbstracts(pos, l.head, l.head, c)) return; for (List m = supertypes; m != l; m = m.tail) if (!checkCompatibleAbstracts(pos, l.head, m.head, c)) return; } checkCompatibleConcretes(pos, c); } /** Check that all non-override equivalent methods accessible from 'site' * are mutually compatible (JLS 8.4.8/9.4.1). * * @param pos Position to be used for error reporting. * @param site The class whose methods are checked. * @param sym The method symbol to be checked. */ void checkOverrideClashes(DiagnosticPosition pos, Type site, MethodSymbol sym) { ClashFilter cf = new ClashFilter(site); //for each method m1 that is overridden (directly or indirectly) //by method 'sym' in 'site'... List potentiallyAmbiguousList = List.nil(); boolean overridesAny = false; ArrayList symbolsByName = new ArrayList<>(); types.membersClosure(site, false).getSymbolsByName(sym.name, cf).forEach(symbolsByName::add); for (Symbol m1 : symbolsByName) { if (!sym.overrides(m1, site.tsym, types, false)) { if (m1 == sym) { continue; } if (!overridesAny) { potentiallyAmbiguousList = potentiallyAmbiguousList.prepend((MethodSymbol)m1); } continue; } if (m1 != sym) { overridesAny = true; potentiallyAmbiguousList = List.nil(); } //...check each method m2 that is a member of 'site' for (Symbol m2 : symbolsByName) { if (m2 == m1) continue; //if (i) the signature of 'sym' is not a subsignature of m1 (seen as //a member of 'site') and (ii) m1 has the same erasure as m2, issue an error if (!types.isSubSignature(sym.type, types.memberType(site, m2), Feature.STRICT_METHOD_CLASH_CHECK.allowedInSource(source)) && types.hasSameArgs(m2.erasure(types), m1.erasure(types))) { sym.flags_field |= CLASH; if (m1 == sym) { log.error(pos, Errors.NameClashSameErasureNoOverride( m1.name, types.memberType(site, m1).asMethodType().getParameterTypes(), m1.location(), m2.name, types.memberType(site, m2).asMethodType().getParameterTypes(), m2.location())); } else { ClassType ct = (ClassType)site; String kind = ct.isInterface() ? "interface" : "class"; log.error(pos, Errors.NameClashSameErasureNoOverride1( kind, ct.tsym.name, m1.name, types.memberType(site, m1).asMethodType().getParameterTypes(), m1.location(), m2.name, types.memberType(site, m2).asMethodType().getParameterTypes(), m2.location())); } return; } } } if (!overridesAny) { for (MethodSymbol m: potentiallyAmbiguousList) { checkPotentiallyAmbiguousOverloads(pos, site, sym, m); } } } /** Check that all static methods accessible from 'site' are * mutually compatible (JLS 8.4.8). * * @param pos Position to be used for error reporting. * @param site The class whose methods are checked. * @param sym The method symbol to be checked. */ void checkHideClashes(DiagnosticPosition pos, Type site, MethodSymbol sym) { ClashFilter cf = new ClashFilter(site); //for each method m1 that is a member of 'site'... for (Symbol s : types.membersClosure(site, true).getSymbolsByName(sym.name, cf)) { //if (i) the signature of 'sym' is not a subsignature of m1 (seen as //a member of 'site') and (ii) 'sym' has the same erasure as m1, issue an error if (!types.isSubSignature(sym.type, types.memberType(site, s), Feature.STRICT_METHOD_CLASH_CHECK.allowedInSource(source))) { if (types.hasSameArgs(s.erasure(types), sym.erasure(types))) { log.error(pos, Errors.NameClashSameErasureNoHide(sym, sym.location(), s, s.location())); return; } else { checkPotentiallyAmbiguousOverloads(pos, site, sym, (MethodSymbol)s); } } } } //where private class ClashFilter implements Predicate { Type site; ClashFilter(Type site) { this.site = site; } boolean shouldSkip(Symbol s) { return (s.flags() & CLASH) != 0 && s.owner == site.tsym; } @Override public boolean test(Symbol s) { return s.kind == MTH && (s.flags() & SYNTHETIC) == 0 && !shouldSkip(s) && s.isInheritedIn(site.tsym, types) && !s.isConstructor(); } } void checkDefaultMethodClashes(DiagnosticPosition pos, Type site) { DefaultMethodClashFilter dcf = new DefaultMethodClashFilter(site); for (Symbol m : types.membersClosure(site, false).getSymbols(dcf)) { Assert.check(m.kind == MTH); List prov = types.interfaceCandidates(site, (MethodSymbol)m); if (prov.size() > 1) { ListBuffer abstracts = new ListBuffer<>(); ListBuffer defaults = new ListBuffer<>(); for (MethodSymbol provSym : prov) { if ((provSym.flags() & DEFAULT) != 0) { defaults = defaults.append(provSym); } else if ((provSym.flags() & ABSTRACT) != 0) { abstracts = abstracts.append(provSym); } if (defaults.nonEmpty() && defaults.size() + abstracts.size() >= 2) { //strong semantics - issue an error if two sibling interfaces //have two override-equivalent defaults - or if one is abstract //and the other is default Fragment diagKey; Symbol s1 = defaults.first(); Symbol s2; if (defaults.size() > 1) { s2 = defaults.toList().tail.head; diagKey = Fragments.IncompatibleUnrelatedDefaults(Kinds.kindName(site.tsym), site, m.name, types.memberType(site, m).getParameterTypes(), s1.location(), s2.location()); } else { s2 = abstracts.first(); diagKey = Fragments.IncompatibleAbstractDefault(Kinds.kindName(site.tsym), site, m.name, types.memberType(site, m).getParameterTypes(), s1.location(), s2.location()); } log.error(pos, Errors.TypesIncompatible(s1.location().type, s2.location().type, diagKey)); break; } } } } } //where private class DefaultMethodClashFilter implements Predicate { Type site; DefaultMethodClashFilter(Type site) { this.site = site; } @Override public boolean test(Symbol s) { return s.kind == MTH && (s.flags() & DEFAULT) != 0 && s.isInheritedIn(site.tsym, types) && !s.isConstructor(); } } /** * Report warnings for potentially ambiguous method declarations. Two declarations * are potentially ambiguous if they feature two unrelated functional interface * in same argument position (in which case, a call site passing an implicit * lambda would be ambiguous). */ void checkPotentiallyAmbiguousOverloads(DiagnosticPosition pos, Type site, MethodSymbol msym1, MethodSymbol msym2) { if (msym1 != msym2 && Feature.DEFAULT_METHODS.allowedInSource(source) && lint.isEnabled(LintCategory.OVERLOADS) && (msym1.flags() & POTENTIALLY_AMBIGUOUS) == 0 && (msym2.flags() & POTENTIALLY_AMBIGUOUS) == 0) { Type mt1 = types.memberType(site, msym1); Type mt2 = types.memberType(site, msym2); //if both generic methods, adjust type variables if (mt1.hasTag(FORALL) && mt2.hasTag(FORALL) && types.hasSameBounds((ForAll)mt1, (ForAll)mt2)) { mt2 = types.subst(mt2, ((ForAll)mt2).tvars, ((ForAll)mt1).tvars); } //expand varargs methods if needed int maxLength = Math.max(mt1.getParameterTypes().length(), mt2.getParameterTypes().length()); List args1 = rs.adjustArgs(mt1.getParameterTypes(), msym1, maxLength, true); List args2 = rs.adjustArgs(mt2.getParameterTypes(), msym2, maxLength, true); //if arities don't match, exit if (args1.length() != args2.length()) return; boolean potentiallyAmbiguous = false; while (args1.nonEmpty() && args2.nonEmpty()) { Type s = args1.head; Type t = args2.head; if (!types.isSubtype(t, s) && !types.isSubtype(s, t)) { if (types.isFunctionalInterface(s) && types.isFunctionalInterface(t) && types.findDescriptorType(s).getParameterTypes().length() > 0 && types.findDescriptorType(s).getParameterTypes().length() == types.findDescriptorType(t).getParameterTypes().length()) { potentiallyAmbiguous = true; } else { return; } } args1 = args1.tail; args2 = args2.tail; } if (potentiallyAmbiguous) { //we found two incompatible functional interfaces with same arity //this means a call site passing an implicit lambda would be ambiguous msym1.flags_field |= POTENTIALLY_AMBIGUOUS; msym2.flags_field |= POTENTIALLY_AMBIGUOUS; log.warning(LintCategory.OVERLOADS, pos, Warnings.PotentiallyAmbiguousOverload(msym1, msym1.location(), msym2, msym2.location())); return; } } } void checkAccessFromSerializableElement(final JCTree tree, boolean isLambda) { if (warnOnAnyAccessToMembers || (lint.isEnabled(LintCategory.SERIAL) && !lint.isSuppressed(LintCategory.SERIAL) && isLambda)) { Symbol sym = TreeInfo.symbol(tree); if (!sym.kind.matches(KindSelector.VAL_MTH)) { return; } if (sym.kind == VAR) { if ((sym.flags() & PARAMETER) != 0 || sym.isDirectlyOrIndirectlyLocal() || sym.name == names._this || sym.name == names._super) { return; } } if (!types.isSubtype(sym.owner.type, syms.serializableType) && isEffectivelyNonPublic(sym)) { if (isLambda) { if (belongsToRestrictedPackage(sym)) { log.warning(LintCategory.SERIAL, tree.pos(), Warnings.AccessToMemberFromSerializableLambda(sym)); } } else { log.warning(tree.pos(), Warnings.AccessToMemberFromSerializableElement(sym)); } } } } private boolean isEffectivelyNonPublic(Symbol sym) { if (sym.packge() == syms.rootPackage) { return false; } while (sym.kind != PCK) { if ((sym.flags() & PUBLIC) == 0) { return true; } sym = sym.owner; } return false; } private boolean belongsToRestrictedPackage(Symbol sym) { String fullName = sym.packge().fullname.toString(); return fullName.startsWith("java.") || fullName.startsWith("javax.") || fullName.startsWith("sun.") || fullName.contains(".internal."); } /** Check that class c does not implement directly or indirectly * the same parameterized interface with two different argument lists. * @param pos Position to be used for error reporting. * @param type The type whose interfaces are checked. */ void checkClassBounds(DiagnosticPosition pos, Type type) { checkClassBounds(pos, new HashMap(), type); } //where /** Enter all interfaces of type `type' into the hash table `seensofar' * with their class symbol as key and their type as value. Make * sure no class is entered with two different types. */ void checkClassBounds(DiagnosticPosition pos, Map seensofar, Type type) { if (type.isErroneous()) return; for (List l = types.interfaces(type); l.nonEmpty(); l = l.tail) { Type it = l.head; if (type.hasTag(CLASS) && !it.hasTag(CLASS)) continue; // JLS 8.1.5 Type oldit = seensofar.put(it.tsym, it); if (oldit != null) { List oldparams = oldit.allparams(); List newparams = it.allparams(); if (!types.containsTypeEquivalent(oldparams, newparams)) log.error(pos, Errors.CantInheritDiffArg(it.tsym, Type.toString(oldparams), Type.toString(newparams))); } checkClassBounds(pos, seensofar, it); } Type st = types.supertype(type); if (type.hasTag(CLASS) && !st.hasTag(CLASS)) return; // JLS 8.1.4 if (st != Type.noType) checkClassBounds(pos, seensofar, st); } /** Enter interface into into set. * If it existed already, issue a "repeated interface" error. */ void checkNotRepeated(DiagnosticPosition pos, Type it, Set its) { if (its.contains(it)) log.error(pos, Errors.RepeatedInterface); else { its.add(it); } } /* ************************************************************************* * Check annotations **************************************************************************/ /** * Recursively validate annotations values */ void validateAnnotationTree(JCTree tree) { class AnnotationValidator extends TreeScanner { @Override public void visitAnnotation(JCAnnotation tree) { if (!tree.type.isErroneous() && tree.type.tsym.isAnnotationType()) { super.visitAnnotation(tree); validateAnnotation(tree); } } } tree.accept(new AnnotationValidator()); } /** * {@literal * Annotation types are restricted to primitives, String, an * enum, an annotation, Class, Class, Class, arrays of the preceding. * } */ void validateAnnotationType(JCTree restype) { // restype may be null if an error occurred, so don't bother validating it if (restype != null) { validateAnnotationType(restype.pos(), restype.type); } } void validateAnnotationType(DiagnosticPosition pos, Type type) { if (type.isPrimitive()) return; if (types.isSameType(type, syms.stringType)) return; if ((type.tsym.flags() & Flags.ENUM) != 0) return; if ((type.tsym.flags() & Flags.ANNOTATION) != 0) return; if (types.cvarLowerBound(type).tsym == syms.classType.tsym) return; if (types.isArray(type) && !types.isArray(types.elemtype(type))) { validateAnnotationType(pos, types.elemtype(type)); return; } log.error(pos, Errors.InvalidAnnotationMemberType); } /** * "It is also a compile-time error if any method declared in an * annotation type has a signature that is override-equivalent to * that of any public or protected method declared in class Object * or in the interface annotation.Annotation." * * @jls 9.6 Annotation Types */ void validateAnnotationMethod(DiagnosticPosition pos, MethodSymbol m) { for (Type sup = syms.annotationType; sup.hasTag(CLASS); sup = types.supertype(sup)) { Scope s = sup.tsym.members(); for (Symbol sym : s.getSymbolsByName(m.name)) { if (sym.kind == MTH && (sym.flags() & (PUBLIC | PROTECTED)) != 0 && types.overrideEquivalent(m.type, sym.type)) log.error(pos, Errors.IntfAnnotationMemberClash(sym, sup)); } } } /** Check the annotations of a symbol. */ public void validateAnnotations(List annotations, JCTree declarationTree, Symbol s) { for (JCAnnotation a : annotations) validateAnnotation(a, declarationTree, s); } /** Check the type annotations. */ public void validateTypeAnnotations(List annotations, boolean isTypeParameter) { for (JCAnnotation a : annotations) validateTypeAnnotation(a, isTypeParameter); } /** Check an annotation of a symbol. */ private void validateAnnotation(JCAnnotation a, JCTree declarationTree, Symbol s) { validateAnnotationTree(a); boolean isRecordMember = ((s.flags_field & RECORD) != 0 || s.enclClass() != null && s.enclClass().isRecord()); boolean isRecordField = (s.flags_field & RECORD) != 0 && declarationTree.hasTag(VARDEF) && s.owner.kind == TYP; if (isRecordField) { // first we need to check if the annotation is applicable to records Name[] targets = getTargetNames(a); boolean appliesToRecords = false; for (Name target : targets) { appliesToRecords = target == names.FIELD || target == names.PARAMETER || target == names.METHOD || target == names.TYPE_USE || target == names.RECORD_COMPONENT; if (appliesToRecords) { break; } } if (!appliesToRecords) { log.error(a.pos(), Errors.AnnotationTypeNotApplicable); } else { /* lets now find the annotations in the field that are targeted to record components and append them to * the corresponding record component */ ClassSymbol recordClass = (ClassSymbol) s.owner; RecordComponent rc = recordClass.getRecordComponent((VarSymbol)s); SymbolMetadata metadata = rc.getMetadata(); if (metadata == null || metadata.isEmpty()) { /* if not is empty then we have already been here, which is the case if multiple annotations are applied * to the record component declaration */ rc.appendAttributes(s.getRawAttributes().stream().filter(anno -> Arrays.stream(getTargetNames(anno.type.tsym)).anyMatch(name -> name == names.RECORD_COMPONENT) ).collect(List.collector())); rc.setTypeAttributes(s.getRawTypeAttributes()); // to get all the type annotations applied to the type rc.type = s.type; } } } /* the section below is tricky. Annotations applied to record components are propagated to the corresponding * record member so if an annotation has target: FIELD, it is propagated to the corresponding FIELD, if it has * target METHOD, it is propagated to the accessor and so on. But at the moment when method members are generated * there is no enough information to propagate only the right annotations. So all the annotations are propagated * to all the possible locations. * * At this point we need to remove all the annotations that are not in place before going on with the annotation * party. On top of the above there is the issue that there is no AST representing record components, just symbols * so the corresponding field has been holding all the annotations and it's metadata has been modified as if it * was both a field and a record component. * * So there are two places where we need to trim annotations from: the metadata of the symbol and / or the modifiers * in the AST. Whatever is in the metadata will be written to the class file, whatever is in the modifiers could * be see by annotation processors. * * The metadata contains both type annotations and declaration annotations. At this point of the game we don't * need to care about type annotations, they are all in the right place. But we could need to remove declaration * annotations. So for declaration annotations if they are not applicable to the record member, excluding type * annotations which are already correct, then we will remove it. For the AST modifiers if the annotation is not * applicable either as type annotation and or declaration annotation, only in that case it will be removed. * * So it could be that annotation is removed as a declaration annotation but it is kept in the AST modifier for * further inspection by annotation processors. * * For example: * * import java.lang.annotation.*; * * @Target({ElementType.TYPE_USE, ElementType.RECORD_COMPONENT}) * @Retention(RetentionPolicy.RUNTIME) * @interface Anno { } * * record R(@Anno String s) {} * * at this point we will have for the case of the generated field: * - @Anno in the modifier * - @Anno as a type annotation * - @Anno as a declaration annotation * * the last one should be removed because the annotation has not FIELD as target but it was applied as a * declaration annotation because the field was being treated both as a field and as a record component * as we have already copied the annotations to the record component, now the field doesn't need to hold * annotations that are not intended for it anymore. Still @Anno has to be kept in the AST's modifiers as it * is applicable as a type annotation to the type of the field. */ if (a.type.tsym.isAnnotationType()) { Optional> applicableTargetsOp = getApplicableTargets(a, s); if (!!applicableTargetsOp.isPresent()) { Set applicableTargets = applicableTargetsOp.get(); boolean notApplicableOrIsTypeUseOnly = applicableTargets.isEmpty() || applicableTargets.size() == 1 && applicableTargets.contains(names.TYPE_USE); boolean isCompGeneratedRecordElement = isRecordMember && (s.flags_field & Flags.GENERATED_MEMBER) != 0; boolean isCompRecordElementWithNonApplicableDeclAnno = isCompGeneratedRecordElement && notApplicableOrIsTypeUseOnly; if (applicableTargets.isEmpty() || isCompRecordElementWithNonApplicableDeclAnno) { if (isCompRecordElementWithNonApplicableDeclAnno) { /* so we have found an annotation that is not applicable to a record member that was generated by the * compiler. This was intentionally done at TypeEnter, now is the moment strip away the annotations * that are not applicable to the given record member */ JCModifiers modifiers = TreeInfo.getModifiers(declarationTree); /* lets first remove the annotation from the modifier if it is not applicable, we have to check again as * it could be a type annotation */ if (modifiers != null && applicableTargets.isEmpty()) { ListBuffer newAnnotations = new ListBuffer<>(); for (JCAnnotation anno : modifiers.annotations) { if (anno != a) { newAnnotations.add(anno); } } modifiers.annotations = newAnnotations.toList(); } // now lets remove it from the symbol s.getMetadata().removeDeclarationMetadata(a.attribute); } else { log.error(a.pos(), Errors.AnnotationTypeNotApplicable); } } /* if we are seeing the @SafeVarargs annotation applied to a compiler generated accessor, * then this is an error as we know that no compiler generated accessor will be a varargs * method, better to fail asap */ if (isCompGeneratedRecordElement && !isRecordField && a.type.tsym == syms.trustMeType.tsym && declarationTree.hasTag(METHODDEF)) { log.error(a.pos(), Errors.VarargsInvalidTrustmeAnno(syms.trustMeType.tsym, Fragments.VarargsTrustmeOnNonVarargsAccessor(s))); } } } if (a.annotationType.type.tsym == syms.functionalInterfaceType.tsym) { if (s.kind != TYP) { log.error(a.pos(), Errors.BadFunctionalIntfAnno); } else if (!s.isInterface() || (s.flags() & ANNOTATION) != 0) { log.error(a.pos(), Errors.BadFunctionalIntfAnno1(Fragments.NotAFunctionalIntf(s))); } } } public void validateTypeAnnotation(JCAnnotation a, boolean isTypeParameter) { Assert.checkNonNull(a.type); validateAnnotationTree(a); if (a.hasTag(TYPE_ANNOTATION) && !a.annotationType.type.isErroneous() && !isTypeAnnotation(a, isTypeParameter)) { log.error(a.pos(), Errors.AnnotationTypeNotApplicableToType(a.type)); } } /** * Validate the proposed container 'repeatable' on the * annotation type symbol 's'. Report errors at position * 'pos'. * * @param s The (annotation)type declaration annotated with a @Repeatable * @param repeatable the @Repeatable on 's' * @param pos where to report errors */ public void validateRepeatable(TypeSymbol s, Attribute.Compound repeatable, DiagnosticPosition pos) { Assert.check(types.isSameType(repeatable.type, syms.repeatableType)); Type t = null; List> l = repeatable.values; if (!l.isEmpty()) { Assert.check(l.head.fst.name == names.value); if (l.head.snd instanceof Attribute.Class) { t = ((Attribute.Class)l.head.snd).getValue(); } } if (t == null) { // errors should already have been reported during Annotate return; } validateValue(t.tsym, s, pos); validateRetention(t.tsym, s, pos); validateDocumented(t.tsym, s, pos); validateInherited(t.tsym, s, pos); validateTarget(t.tsym, s, pos); validateDefault(t.tsym, pos); } private void validateValue(TypeSymbol container, TypeSymbol contained, DiagnosticPosition pos) { Symbol sym = container.members().findFirst(names.value); if (sym != null && sym.kind == MTH) { MethodSymbol m = (MethodSymbol) sym; Type ret = m.getReturnType(); if (!(ret.hasTag(ARRAY) && types.isSameType(((ArrayType)ret).elemtype, contained.type))) { log.error(pos, Errors.InvalidRepeatableAnnotationValueReturn(container, ret, types.makeArrayType(contained.type))); } } else { log.error(pos, Errors.InvalidRepeatableAnnotationNoValue(container)); } } private void validateRetention(TypeSymbol container, TypeSymbol contained, DiagnosticPosition pos) { Attribute.RetentionPolicy containerRetention = types.getRetention(container); Attribute.RetentionPolicy containedRetention = types.getRetention(contained); boolean error = false; switch (containedRetention) { case RUNTIME: if (containerRetention != Attribute.RetentionPolicy.RUNTIME) { error = true; } break; case CLASS: if (containerRetention == Attribute.RetentionPolicy.SOURCE) { error = true; } } if (error ) { log.error(pos, Errors.InvalidRepeatableAnnotationRetention(container, containerRetention.name(), contained, containedRetention.name())); } } private void validateDocumented(Symbol container, Symbol contained, DiagnosticPosition pos) { if (contained.attribute(syms.documentedType.tsym) != null) { if (container.attribute(syms.documentedType.tsym) == null) { log.error(pos, Errors.InvalidRepeatableAnnotationNotDocumented(container, contained)); } } } private void validateInherited(Symbol container, Symbol contained, DiagnosticPosition pos) { if (contained.attribute(syms.inheritedType.tsym) != null) { if (container.attribute(syms.inheritedType.tsym) == null) { log.error(pos, Errors.InvalidRepeatableAnnotationNotInherited(container, contained)); } } } private void validateTarget(TypeSymbol container, TypeSymbol contained, DiagnosticPosition pos) { // The set of targets the container is applicable to must be a subset // (with respect to annotation target semantics) of the set of targets // the contained is applicable to. The target sets may be implicit or // explicit. Set containerTargets; Attribute.Array containerTarget = getAttributeTargetAttribute(container); if (containerTarget == null) { containerTargets = getDefaultTargetSet(); } else { containerTargets = new HashSet<>(); for (Attribute app : containerTarget.values) { if (!(app instanceof Attribute.Enum attributeEnum)) { continue; // recovery } containerTargets.add(attributeEnum.value.name); } } Set containedTargets; Attribute.Array containedTarget = getAttributeTargetAttribute(contained); if (containedTarget == null) { containedTargets = getDefaultTargetSet(); } else { containedTargets = new HashSet<>(); for (Attribute app : containedTarget.values) { if (!(app instanceof Attribute.Enum attributeEnum)) { continue; // recovery } containedTargets.add(attributeEnum.value.name); } } if (!isTargetSubsetOf(containerTargets, containedTargets)) { log.error(pos, Errors.InvalidRepeatableAnnotationIncompatibleTarget(container, contained)); } } /* get a set of names for the default target */ private Set getDefaultTargetSet() { if (defaultTargets == null) { defaultTargets = Collections.unmodifiableSet(new HashSet<>(Arrays.asList(defaultTargetMetaInfo()))); } return defaultTargets; } private Set defaultTargets; /** Checks that s is a subset of t, with respect to ElementType * semantics, specifically {ANNOTATION_TYPE} is a subset of {TYPE}, * and {TYPE_USE} covers the set {ANNOTATION_TYPE, TYPE, TYPE_USE, * TYPE_PARAMETER}. */ private boolean isTargetSubsetOf(Set s, Set t) { // Check that all elements in s are present in t for (Name n2 : s) { boolean currentElementOk = false; for (Name n1 : t) { if (n1 == n2) { currentElementOk = true; break; } else if (n1 == names.TYPE && n2 == names.ANNOTATION_TYPE) { currentElementOk = true; break; } else if (n1 == names.TYPE_USE && (n2 == names.TYPE || n2 == names.ANNOTATION_TYPE || n2 == names.TYPE_PARAMETER)) { currentElementOk = true; break; } } if (!currentElementOk) return false; } return true; } private void validateDefault(Symbol container, DiagnosticPosition pos) { // validate that all other elements of containing type has defaults Scope scope = container.members(); for(Symbol elm : scope.getSymbols()) { if (elm.name != names.value && elm.kind == MTH && ((MethodSymbol)elm).defaultValue == null) { log.error(pos, Errors.InvalidRepeatableAnnotationElemNondefault(container, elm)); } } } /** Is s a method symbol that overrides a method in a superclass? */ boolean isOverrider(Symbol s) { if (s.kind != MTH || s.isStatic()) return false; MethodSymbol m = (MethodSymbol)s; TypeSymbol owner = (TypeSymbol)m.owner; for (Type sup : types.closure(owner.type)) { if (sup == owner.type) continue; // skip "this" Scope scope = sup.tsym.members(); for (Symbol sym : scope.getSymbolsByName(m.name)) { if (!sym.isStatic() && m.overrides(sym, owner, types, true)) return true; } } return false; } /** Is the annotation applicable to types? */ protected boolean isTypeAnnotation(JCAnnotation a, boolean isTypeParameter) { List targets = typeAnnotations.annotationTargets(a.annotationType.type.tsym); return (targets == null) ? false : targets.stream() .anyMatch(attr -> isTypeAnnotation(attr, isTypeParameter)); } //where boolean isTypeAnnotation(Attribute a, boolean isTypeParameter) { Attribute.Enum e = (Attribute.Enum)a; return (e.value.name == names.TYPE_USE || (isTypeParameter && e.value.name == names.TYPE_PARAMETER)); } /** Is the annotation applicable to the symbol? */ Name[] getTargetNames(JCAnnotation a) { return getTargetNames(a.annotationType.type.tsym); } public Name[] getTargetNames(TypeSymbol annoSym) { Attribute.Array arr = getAttributeTargetAttribute(annoSym); Name[] targets; if (arr == null) { targets = defaultTargetMetaInfo(); } else { // TODO: can we optimize this? targets = new Name[arr.values.length]; for (int i=0; i> targets = getApplicableTargets(a, s); /* the optional could be empty if the annotation is unknown in that case * we return that it is applicable and if it is erroneous that should imply * an error at the declaration site */ return !targets.isPresent() || targets.isPresent() && !targets.get().isEmpty(); } Optional> getApplicableTargets(JCAnnotation a, Symbol s) { Attribute.Array arr = getAttributeTargetAttribute(a.annotationType.type.tsym); Name[] targets; Set applicableTargets = new HashSet<>(); if (arr == null) { targets = defaultTargetMetaInfo(); } else { // TODO: can we optimize this? targets = new Name[arr.values.length]; for (int i=0; i defaultTargets = new ArrayList<>(); defaultTargets.add(names.PACKAGE); defaultTargets.add(names.TYPE); defaultTargets.add(names.FIELD); defaultTargets.add(names.METHOD); defaultTargets.add(names.CONSTRUCTOR); defaultTargets.add(names.ANNOTATION_TYPE); defaultTargets.add(names.LOCAL_VARIABLE); defaultTargets.add(names.PARAMETER); if (allowRecords) { defaultTargets.add(names.RECORD_COMPONENT); } if (allowModules) { defaultTargets.add(names.MODULE); } dfltTargetMeta = defaultTargets.toArray(new Name[0]); } return dfltTargetMeta; } /** Check an annotation value. * * @param a The annotation tree to check * @return true if this annotation tree is valid, otherwise false */ public boolean validateAnnotationDeferErrors(JCAnnotation a) { boolean res = false; final Log.DiagnosticHandler diagHandler = new Log.DiscardDiagnosticHandler(log); try { res = validateAnnotation(a); } finally { log.popDiagnosticHandler(diagHandler); } return res; } private boolean validateAnnotation(JCAnnotation a) { boolean isValid = true; AnnotationTypeMetadata metadata = a.annotationType.type.tsym.getAnnotationTypeMetadata(); // collect an inventory of the annotation elements Set elements = metadata.getAnnotationElements(); // remove the ones that are assigned values for (JCTree arg : a.args) { if (!arg.hasTag(ASSIGN)) continue; // recovery JCAssign assign = (JCAssign)arg; Symbol m = TreeInfo.symbol(assign.lhs); if (m == null || m.type.isErroneous()) continue; if (!elements.remove(m)) { isValid = false; log.error(assign.lhs.pos(), Errors.DuplicateAnnotationMemberValue(m.name, a.type)); } } // all the remaining ones better have default values List missingDefaults = List.nil(); Set membersWithDefault = metadata.getAnnotationElementsWithDefault(); for (MethodSymbol m : elements) { if (m.type.isErroneous()) continue; if (!membersWithDefault.contains(m)) missingDefaults = missingDefaults.append(m.name); } missingDefaults = missingDefaults.reverse(); if (missingDefaults.nonEmpty()) { isValid = false; Error errorKey = (missingDefaults.size() > 1) ? Errors.AnnotationMissingDefaultValue1(a.type, missingDefaults) : Errors.AnnotationMissingDefaultValue(a.type, missingDefaults); log.error(a.pos(), errorKey); } return isValid && validateTargetAnnotationValue(a); } /* Validate the special java.lang.annotation.Target annotation */ boolean validateTargetAnnotationValue(JCAnnotation a) { // special case: java.lang.annotation.Target must not have // repeated values in its value member if (a.annotationType.type.tsym != syms.annotationTargetType.tsym || a.args.tail == null) return true; boolean isValid = true; if (!a.args.head.hasTag(ASSIGN)) return false; // error recovery JCAssign assign = (JCAssign) a.args.head; Symbol m = TreeInfo.symbol(assign.lhs); if (m.name != names.value) return false; JCTree rhs = assign.rhs; if (!rhs.hasTag(NEWARRAY)) return false; JCNewArray na = (JCNewArray) rhs; Set targets = new HashSet<>(); for (JCTree elem : na.elems) { if (!targets.add(TreeInfo.symbol(elem))) { isValid = false; log.error(elem.pos(), Errors.RepeatedAnnotationTarget); } } return isValid; } void checkDeprecatedAnnotation(DiagnosticPosition pos, Symbol s) { if (lint.isEnabled(LintCategory.DEP_ANN) && s.isDeprecatableViaAnnotation() && (s.flags() & DEPRECATED) != 0 && !syms.deprecatedType.isErroneous() && s.attribute(syms.deprecatedType.tsym) == null) { log.warning(LintCategory.DEP_ANN, pos, Warnings.MissingDeprecatedAnnotation); } // Note: @Deprecated has no effect on local variables, parameters and package decls. if (lint.isEnabled(LintCategory.DEPRECATION) && !s.isDeprecatableViaAnnotation()) { if (!syms.deprecatedType.isErroneous() && s.attribute(syms.deprecatedType.tsym) != null) { log.warning(LintCategory.DEPRECATION, pos, Warnings.DeprecatedAnnotationHasNoEffect(Kinds.kindName(s))); } } } void checkDeprecated(final DiagnosticPosition pos, final Symbol other, final Symbol s) { checkDeprecated(() -> pos, other, s); } void checkDeprecated(Supplier pos, final Symbol other, final Symbol s) { if ( (s.isDeprecatedForRemoval() || s.isDeprecated() && !other.isDeprecated()) && (s.outermostClass() != other.outermostClass() || s.outermostClass() == null) && s.kind != Kind.PCK) { deferredLintHandler.report(() -> warnDeprecated(pos.get(), s)); } } void checkSunAPI(final DiagnosticPosition pos, final Symbol s) { if ((s.flags() & PROPRIETARY) != 0) { deferredLintHandler.report(() -> { log.mandatoryWarning(pos, Warnings.SunProprietary(s)); }); } } void checkProfile(final DiagnosticPosition pos, final Symbol s) { if (profile != Profile.DEFAULT && (s.flags() & NOT_IN_PROFILE) != 0) { log.error(pos, Errors.NotInProfile(s, profile)); } } void checkPreview(DiagnosticPosition pos, Symbol other, Symbol s) { if ((s.flags() & PREVIEW_API) != 0 && !preview.participatesInPreview(other, s)) { if ((s.flags() & PREVIEW_REFLECTIVE) == 0) { if (!preview.isEnabled()) { log.error(pos, Errors.IsPreview(s)); } else { preview.markUsesPreview(pos); deferredLintHandler.report(() -> warnPreviewAPI(pos, Warnings.IsPreview(s))); } } else { deferredLintHandler.report(() -> warnPreviewAPI(pos, Warnings.IsPreviewReflective(s))); } } if (preview.declaredUsingPreviewFeature(s)) { if (preview.isEnabled()) { //for preview disabled do presumably so not need to do anything? //If "s" is compiled from source, then there was an error for it already; //if "s" is from classfile, there already was an error for the classfile. preview.markUsesPreview(pos); deferredLintHandler.report(() -> warnDeclaredUsingPreview(pos, s)); } } } /* ************************************************************************* * Check for recursive annotation elements. **************************************************************************/ /** Check for cycles in the graph of annotation elements. */ void checkNonCyclicElements(JCClassDecl tree) { if ((tree.sym.flags_field & ANNOTATION) == 0) return; Assert.check((tree.sym.flags_field & LOCKED) == 0); try { tree.sym.flags_field |= LOCKED; for (JCTree def : tree.defs) { if (!def.hasTag(METHODDEF)) continue; JCMethodDecl meth = (JCMethodDecl)def; checkAnnotationResType(meth.pos(), meth.restype.type); } } finally { tree.sym.flags_field &= ~LOCKED; tree.sym.flags_field |= ACYCLIC_ANN; } } void checkNonCyclicElementsInternal(DiagnosticPosition pos, TypeSymbol tsym) { if ((tsym.flags_field & ACYCLIC_ANN) != 0) return; if ((tsym.flags_field & LOCKED) != 0) { log.error(pos, Errors.CyclicAnnotationElement(tsym)); return; } try { tsym.flags_field |= LOCKED; for (Symbol s : tsym.members().getSymbols(NON_RECURSIVE)) { if (s.kind != MTH) continue; checkAnnotationResType(pos, ((MethodSymbol)s).type.getReturnType()); } } finally { tsym.flags_field &= ~LOCKED; tsym.flags_field |= ACYCLIC_ANN; } } void checkAnnotationResType(DiagnosticPosition pos, Type type) { switch (type.getTag()) { case CLASS: if ((type.tsym.flags() & ANNOTATION) != 0) checkNonCyclicElementsInternal(pos, type.tsym); break; case ARRAY: checkAnnotationResType(pos, types.elemtype(type)); break; default: break; // int etc } } /* ************************************************************************* * Check for cycles in the constructor call graph. **************************************************************************/ /** Check for cycles in the graph of constructors calling other * constructors. */ void checkCyclicConstructors(JCClassDecl tree) { Map callMap = new HashMap<>(); // enter each constructor this-call into the map for (List l = tree.defs; l.nonEmpty(); l = l.tail) { JCMethodInvocation app = TreeInfo.firstConstructorCall(l.head); if (app == null) continue; JCMethodDecl meth = (JCMethodDecl) l.head; if (TreeInfo.name(app.meth) == names._this) { callMap.put(meth.sym, TreeInfo.symbol(app.meth)); } else { meth.sym.flags_field |= ACYCLIC; } } // Check for cycles in the map Symbol[] ctors = new Symbol[0]; ctors = callMap.keySet().toArray(ctors); for (Symbol caller : ctors) { checkCyclicConstructor(tree, caller, callMap); } } /** Look in the map to see if the given constructor is part of a * call cycle. */ private void checkCyclicConstructor(JCClassDecl tree, Symbol ctor, Map callMap) { if (ctor != null && (ctor.flags_field & ACYCLIC) == 0) { if ((ctor.flags_field & LOCKED) != 0) { log.error(TreeInfo.diagnosticPositionFor(ctor, tree), Errors.RecursiveCtorInvocation); } else { ctor.flags_field |= LOCKED; checkCyclicConstructor(tree, callMap.remove(ctor), callMap); ctor.flags_field &= ~LOCKED; } ctor.flags_field |= ACYCLIC; } } /* ************************************************************************* * Miscellaneous **************************************************************************/ /** * Check for division by integer constant zero * @param pos Position for error reporting. * @param operator The operator for the expression * @param operand The right hand operand for the expression */ void checkDivZero(final DiagnosticPosition pos, Symbol operator, Type operand) { if (operand.constValue() != null && operand.getTag().isSubRangeOf(LONG) && ((Number) (operand.constValue())).longValue() == 0) { int opc = ((OperatorSymbol)operator).opcode; if (opc == ByteCodes.idiv || opc == ByteCodes.imod || opc == ByteCodes.ldiv || opc == ByteCodes.lmod) { deferredLintHandler.report(() -> warnDivZero(pos)); } } } /** * Check for empty statements after if */ void checkEmptyIf(JCIf tree) { if (tree.thenpart.hasTag(SKIP) && tree.elsepart == null && lint.isEnabled(LintCategory.EMPTY)) log.warning(LintCategory.EMPTY, tree.thenpart.pos(), Warnings.EmptyIf); } /** Check that symbol is unique in given scope. * @param pos Position for error reporting. * @param sym The symbol. * @param s The scope. */ boolean checkUnique(DiagnosticPosition pos, Symbol sym, Scope s) { if (sym.type.isErroneous()) return true; if (sym.owner.name == names.any) return false; for (Symbol byName : s.getSymbolsByName(sym.name, NON_RECURSIVE)) { if (sym != byName && (byName.flags() & CLASH) == 0 && sym.kind == byName.kind && sym.name != names.error && (sym.kind != MTH || types.hasSameArgs(sym.type, byName.type) || types.hasSameArgs(types.erasure(sym.type), types.erasure(byName.type)))) { if ((sym.flags() & VARARGS) != (byName.flags() & VARARGS)) { sym.flags_field |= CLASH; varargsDuplicateError(pos, sym, byName); return true; } else if (sym.kind == MTH && !types.hasSameArgs(sym.type, byName.type, false)) { duplicateErasureError(pos, sym, byName); sym.flags_field |= CLASH; return true; } else if ((sym.flags() & MATCH_BINDING) != 0 && (byName.flags() & MATCH_BINDING) != 0 && (byName.flags() & MATCH_BINDING_TO_OUTER) == 0) { if (!sym.type.isErroneous()) { log.error(pos, Errors.MatchBindingExists); sym.flags_field |= CLASH; } return false; } else { duplicateError(pos, byName); return false; } } } return true; } /** Report duplicate declaration error. */ void duplicateErasureError(DiagnosticPosition pos, Symbol sym1, Symbol sym2) { if (!sym1.type.isErroneous() && !sym2.type.isErroneous()) { log.error(pos, Errors.NameClashSameErasure(sym1, sym2)); } } /**Check that types imported through the ordinary imports don't clash with types imported * by other (static or ordinary) imports. Note that two static imports may import two clashing * types without an error on the imports. * @param toplevel The toplevel tree for which the test should be performed. */ void checkImportsUnique(JCCompilationUnit toplevel) { WriteableScope ordinallyImportedSoFar = WriteableScope.create(toplevel.packge); WriteableScope staticallyImportedSoFar = WriteableScope.create(toplevel.packge); WriteableScope topLevelScope = toplevel.toplevelScope; for (JCTree def : toplevel.defs) { if (!def.hasTag(IMPORT)) continue; JCImport imp = (JCImport) def; if (imp.importScope == null) continue; for (Symbol sym : imp.importScope.getSymbols(sym -> sym.kind == TYP)) { if (imp.isStatic()) { checkUniqueImport(imp.pos(), ordinallyImportedSoFar, staticallyImportedSoFar, topLevelScope, sym, true); staticallyImportedSoFar.enter(sym); } else { checkUniqueImport(imp.pos(), ordinallyImportedSoFar, staticallyImportedSoFar, topLevelScope, sym, false); ordinallyImportedSoFar.enter(sym); } } imp.importScope = null; } } /** Check that single-type import is not already imported or top-level defined, * but make an exception for two single-type imports which denote the same type. * @param pos Position for error reporting. * @param ordinallyImportedSoFar A Scope containing types imported so far through * ordinary imports. * @param staticallyImportedSoFar A Scope containing types imported so far through * static imports. * @param topLevelScope The current file's top-level Scope * @param sym The symbol. * @param staticImport Whether or not this was a static import */ private boolean checkUniqueImport(DiagnosticPosition pos, Scope ordinallyImportedSoFar, Scope staticallyImportedSoFar, Scope topLevelScope, Symbol sym, boolean staticImport) { Predicate duplicates = candidate -> candidate != sym && !candidate.type.isErroneous(); Symbol ordinaryClashing = ordinallyImportedSoFar.findFirst(sym.name, duplicates); Symbol staticClashing = null; if (ordinaryClashing == null && !staticImport) { staticClashing = staticallyImportedSoFar.findFirst(sym.name, duplicates); } if (ordinaryClashing != null || staticClashing != null) { if (ordinaryClashing != null) log.error(pos, Errors.AlreadyDefinedSingleImport(ordinaryClashing)); else log.error(pos, Errors.AlreadyDefinedStaticSingleImport(staticClashing)); return false; } Symbol clashing = topLevelScope.findFirst(sym.name, duplicates); if (clashing != null) { log.error(pos, Errors.AlreadyDefinedThisUnit(clashing)); return false; } return true; } /** Check that a qualified name is in canonical form (for import decls). */ public void checkCanonical(JCTree tree) { if (!isCanonical(tree)) log.error(tree.pos(), Errors.ImportRequiresCanonical(TreeInfo.symbol(tree))); } // where private boolean isCanonical(JCTree tree) { while (tree.hasTag(SELECT)) { JCFieldAccess s = (JCFieldAccess) tree; if (s.sym.owner.getQualifiedName() != TreeInfo.symbol(s.selected).getQualifiedName()) return false; tree = s.selected; } return true; } /** Check that an auxiliary class is not accessed from any other file than its own. */ void checkForBadAuxiliaryClassAccess(DiagnosticPosition pos, Env env, ClassSymbol c) { if (lint.isEnabled(Lint.LintCategory.AUXILIARYCLASS) && (c.flags() & AUXILIARY) != 0 && rs.isAccessible(env, c) && !fileManager.isSameFile(c.sourcefile, env.toplevel.sourcefile)) { log.warning(pos, Warnings.AuxiliaryClassAccessedFromOutsideOfItsSourceFile(c, c.sourcefile)); } } /** * Check for a default constructor in an exported package. */ void checkDefaultConstructor(ClassSymbol c, DiagnosticPosition pos) { if (lint.isEnabled(LintCategory.MISSING_EXPLICIT_CTOR) && ((c.flags() & (ENUM | RECORD)) == 0) && !c.isAnonymous() && ((c.flags() & (PUBLIC | PROTECTED)) != 0) && Feature.MODULES.allowedInSource(source)) { NestingKind nestingKind = c.getNestingKind(); switch (nestingKind) { case ANONYMOUS, LOCAL -> {return;} case TOP_LEVEL -> {;} // No additional checks needed case MEMBER -> { // For nested member classes, all the enclosing // classes must be public or protected. Symbol owner = c.owner; while (owner != null && owner.kind == TYP) { if ((owner.flags() & (PUBLIC | PROTECTED)) == 0) return; owner = owner.owner; } } } // Only check classes in named packages exported by its module PackageSymbol pkg = c.packge(); if (!pkg.isUnnamed()) { ModuleSymbol modle = pkg.modle; for (ExportsDirective exportDir : modle.exports) { // Report warning only if the containing // package is unconditionally exported if (exportDir.packge.equals(pkg)) { if (exportDir.modules == null || exportDir.modules.isEmpty()) { // Warning may be suppressed by // annotations; check again for being // enabled in the deferred context. deferredLintHandler.report(() -> { if (lint.isEnabled(LintCategory.MISSING_EXPLICIT_CTOR)) log.warning(LintCategory.MISSING_EXPLICIT_CTOR, pos, Warnings.MissingExplicitCtor(c, pkg, modle)); }); } else { return; } } } } } return; } private class ConversionWarner extends Warner { final String uncheckedKey; final Type found; final Type expected; public ConversionWarner(DiagnosticPosition pos, String uncheckedKey, Type found, Type expected) { super(pos); this.uncheckedKey = uncheckedKey; this.found = found; this.expected = expected; } @Override public void warn(LintCategory lint) { boolean warned = this.warned; super.warn(lint); if (warned) return; // suppress redundant diagnostics switch (lint) { case UNCHECKED: Check.this.warnUnchecked(pos(), Warnings.ProbFoundReq(diags.fragment(uncheckedKey), found, expected)); break; case VARARGS: if (method != null && method.attribute(syms.trustMeType.tsym) != null && isTrustMeAllowedOnMethod(method) && !types.isReifiable(method.type.getParameterTypes().last())) { Check.this.warnUnsafeVararg(pos(), Warnings.VarargsUnsafeUseVarargsParam(method.params.last())); } break; default: throw new AssertionError("Unexpected lint: " + lint); } } } public Warner castWarner(DiagnosticPosition pos, Type found, Type expected) { return new ConversionWarner(pos, "unchecked.cast.to.type", found, expected); } public Warner convertWarner(DiagnosticPosition pos, Type found, Type expected) { return new ConversionWarner(pos, "unchecked.assign", found, expected); } public void checkFunctionalInterface(JCClassDecl tree, ClassSymbol cs) { Compound functionalType = cs.attribute(syms.functionalInterfaceType.tsym); if (functionalType != null) { try { types.findDescriptorSymbol((TypeSymbol)cs); } catch (Types.FunctionDescriptorLookupError ex) { DiagnosticPosition pos = tree.pos(); for (JCAnnotation a : tree.getModifiers().annotations) { if (a.annotationType.type.tsym == syms.functionalInterfaceType.tsym) { pos = a.pos(); break; } } log.error(pos, Errors.BadFunctionalIntfAnno1(ex.getDiagnostic())); } } } public void checkImportsResolvable(final JCCompilationUnit toplevel) { for (final JCImport imp : toplevel.getImports()) { if (!imp.staticImport || !imp.qualid.hasTag(SELECT)) continue; final JCFieldAccess select = (JCFieldAccess) imp.qualid; final Symbol origin; if (select.name == names.asterisk || (origin = TreeInfo.symbol(select.selected)) == null || origin.kind != TYP) continue; TypeSymbol site = (TypeSymbol) TreeInfo.symbol(select.selected); if (!checkTypeContainsImportableElement(site, site, toplevel.packge, select.name, new HashSet())) { log.error(imp.pos(), Errors.CantResolveLocation(KindName.STATIC, select.name, null, null, Fragments.Location(kindName(site), site, null))); } } } // Check that packages imported are in scope (JLS 7.4.3, 6.3, 6.5.3.1, 6.5.3.2) public void checkImportedPackagesObservable(final JCCompilationUnit toplevel) { OUTER: for (JCImport imp : toplevel.getImports()) { if (!imp.staticImport && TreeInfo.name(imp.qualid) == names.asterisk) { TypeSymbol tsym = ((JCFieldAccess)imp.qualid).selected.type.tsym; if (tsym.kind == PCK && tsym.members().isEmpty() && !(Feature.IMPORT_ON_DEMAND_OBSERVABLE_PACKAGES.allowedInSource(source) && tsym.exists())) { log.error(DiagnosticFlag.RESOLVE_ERROR, imp.pos, Errors.DoesntExist(tsym)); } } } } private boolean checkTypeContainsImportableElement(TypeSymbol tsym, TypeSymbol origin, PackageSymbol packge, Name name, Set processed) { if (tsym == null || !processed.add(tsym)) return false; // also search through inherited names if (checkTypeContainsImportableElement(types.supertype(tsym.type).tsym, origin, packge, name, processed)) return true; for (Type t : types.interfaces(tsym.type)) if (checkTypeContainsImportableElement(t.tsym, origin, packge, name, processed)) return true; for (Symbol sym : tsym.members().getSymbolsByName(name)) { if (sym.isStatic() && importAccessible(sym, packge) && sym.isMemberOf(origin, types)) { return true; } } return false; } // is the sym accessible everywhere in packge? public boolean importAccessible(Symbol sym, PackageSymbol packge) { try { int flags = (int)(sym.flags() & AccessFlags); switch (flags) { default: case PUBLIC: return true; case PRIVATE: return false; case 0: case PROTECTED: return sym.packge() == packge; } } catch (ClassFinder.BadClassFile err) { throw err; } catch (CompletionFailure ex) { return false; } } public void checkLeaksNotAccessible(Env env, JCClassDecl check) { JCCompilationUnit toplevel = env.toplevel; if ( toplevel.modle == syms.unnamedModule || toplevel.modle == syms.noModule || (check.sym.flags() & COMPOUND) != 0) { return ; } ExportsDirective currentExport = findExport(toplevel.packge); if ( currentExport == null //not exported || currentExport.modules != null) //don't check classes in qualified export return ; new TreeScanner() { Lint lint = env.info.lint; boolean inSuperType; @Override public void visitBlock(JCBlock tree) { } @Override public void visitMethodDef(JCMethodDecl tree) { if (!isAPISymbol(tree.sym)) return; Lint prevLint = lint; try { lint = lint.augment(tree.sym); if (lint.isEnabled(LintCategory.EXPORTS)) { super.visitMethodDef(tree); } } finally { lint = prevLint; } } @Override public void visitVarDef(JCVariableDecl tree) { if (!isAPISymbol(tree.sym) && tree.sym.owner.kind != MTH) return; Lint prevLint = lint; try { lint = lint.augment(tree.sym); if (lint.isEnabled(LintCategory.EXPORTS)) { scan(tree.mods); scan(tree.vartype); } } finally { lint = prevLint; } } @Override public void visitClassDef(JCClassDecl tree) { if (tree != check) return ; if (!isAPISymbol(tree.sym)) return ; Lint prevLint = lint; try { lint = lint.augment(tree.sym); if (lint.isEnabled(LintCategory.EXPORTS)) { scan(tree.mods); scan(tree.typarams); try { inSuperType = true; scan(tree.extending); scan(tree.implementing); } finally { inSuperType = false; } scan(tree.defs); } } finally { lint = prevLint; } } @Override public void visitTypeApply(JCTypeApply tree) { scan(tree.clazz); boolean oldInSuperType = inSuperType; try { inSuperType = false; scan(tree.arguments); } finally { inSuperType = oldInSuperType; } } @Override public void visitIdent(JCIdent tree) { Symbol sym = TreeInfo.symbol(tree); if (sym.kind == TYP && !sym.type.hasTag(TYPEVAR)) { checkVisible(tree.pos(), sym, toplevel.packge, inSuperType); } } @Override public void visitSelect(JCFieldAccess tree) { Symbol sym = TreeInfo.symbol(tree); Symbol sitesym = TreeInfo.symbol(tree.selected); if (sym.kind == TYP && sitesym.kind == PCK) { checkVisible(tree.pos(), sym, toplevel.packge, inSuperType); } else { super.visitSelect(tree); } } @Override public void visitAnnotation(JCAnnotation tree) { if (tree.attribute.type.tsym.getAnnotation(java.lang.annotation.Documented.class) != null) super.visitAnnotation(tree); } }.scan(check); } //where: private ExportsDirective findExport(PackageSymbol pack) { for (ExportsDirective d : pack.modle.exports) { if (d.packge == pack) return d; } return null; } private boolean isAPISymbol(Symbol sym) { while (sym.kind != PCK) { if ((sym.flags() & Flags.PUBLIC) == 0 && (sym.flags() & Flags.PROTECTED) == 0) { return false; } sym = sym.owner; } return true; } private void checkVisible(DiagnosticPosition pos, Symbol what, PackageSymbol inPackage, boolean inSuperType) { if (!isAPISymbol(what) && !inSuperType) { //package private/private element log.warning(LintCategory.EXPORTS, pos, Warnings.LeaksNotAccessible(kindName(what), what, what.packge().modle)); return ; } PackageSymbol whatPackage = what.packge(); ExportsDirective whatExport = findExport(whatPackage); ExportsDirective inExport = findExport(inPackage); if (whatExport == null) { //package not exported: log.warning(LintCategory.EXPORTS, pos, Warnings.LeaksNotAccessibleUnexported(kindName(what), what, what.packge().modle)); return ; } if (whatExport.modules != null) { if (inExport.modules == null || !whatExport.modules.containsAll(inExport.modules)) { log.warning(LintCategory.EXPORTS, pos, Warnings.LeaksNotAccessibleUnexportedQualified(kindName(what), what, what.packge().modle)); } } if (whatPackage.modle != inPackage.modle && whatPackage.modle != syms.java_base) { //check that relativeTo.modle requires transitive what.modle, somehow: List todo = List.of(inPackage.modle); while (todo.nonEmpty()) { ModuleSymbol current = todo.head; todo = todo.tail; if (current == whatPackage.modle) return ; //OK if ((current.flags() & Flags.AUTOMATIC_MODULE) != 0) continue; //for automatic modules, don't look into their dependencies for (RequiresDirective req : current.requires) { if (req.isTransitive()) { todo = todo.prepend(req.module); } } } log.warning(LintCategory.EXPORTS, pos, Warnings.LeaksNotAccessibleNotRequiredTransitive(kindName(what), what, what.packge().modle)); } } void checkModuleExists(final DiagnosticPosition pos, ModuleSymbol msym) { if (msym.kind != MDL) { deferredLintHandler.report(() -> { if (lint.isEnabled(LintCategory.MODULE)) log.warning(LintCategory.MODULE, pos, Warnings.ModuleNotFound(msym)); }); } } void checkPackageExistsForOpens(final DiagnosticPosition pos, PackageSymbol packge) { if (packge.members().isEmpty() && ((packge.flags() & Flags.HAS_RESOURCE) == 0)) { deferredLintHandler.report(() -> { if (lint.isEnabled(LintCategory.OPENS)) log.warning(pos, Warnings.PackageEmptyOrNotFound(packge)); }); } } void checkModuleRequires(final DiagnosticPosition pos, final RequiresDirective rd) { if ((rd.module.flags() & Flags.AUTOMATIC_MODULE) != 0) { deferredLintHandler.report(() -> { if (rd.isTransitive() && lint.isEnabled(LintCategory.REQUIRES_TRANSITIVE_AUTOMATIC)) { log.warning(pos, Warnings.RequiresTransitiveAutomatic); } else if (lint.isEnabled(LintCategory.REQUIRES_AUTOMATIC)) { log.warning(pos, Warnings.RequiresAutomatic); } }); } } /** * Verify the case labels conform to the constraints. Checks constraints related * combinations of patterns and other labels. * * @param cases the cases that should be checked. */ void checkSwitchCaseStructure(List cases) { boolean wasConstant = false; // Seen a constant in the same case label boolean wasDefault = false; // Seen a default in the same case label boolean wasNullPattern = false; // Seen a null pattern in the same case label, //or fall through from a null pattern boolean wasPattern = false; // Seen a pattern in the same case label //or fall through from a pattern boolean wasTypePattern = false; // Seen a pattern in the same case label //or fall through from a type pattern boolean wasNonEmptyFallThrough = false; for (List l = cases; l.nonEmpty(); l = l.tail) { JCCase c = l.head; for (JCCaseLabel label : c.labels) { if (label.hasTag(CONSTANTCASELABEL)) { JCExpression expr = ((JCConstantCaseLabel) label).expr; if (TreeInfo.isNull(expr)) { if (wasPattern && !wasTypePattern && !wasNonEmptyFallThrough) { log.error(label.pos(), Errors.FlowsThroughFromPattern); } wasNullPattern = true; } else { if (wasPattern && !wasNonEmptyFallThrough) { log.error(label.pos(), Errors.FlowsThroughFromPattern); } wasConstant = true; } } else if (label.hasTag(DEFAULTCASELABEL)) { if (wasPattern && !wasNonEmptyFallThrough) { log.error(label.pos(), Errors.FlowsThroughFromPattern); } wasDefault = true; } else { JCPattern pat = ((JCPatternCaseLabel) label).pat; while (pat instanceof JCParenthesizedPattern parenthesized) { pat = parenthesized.pattern; } boolean isTypePattern = pat.hasTag(BINDINGPATTERN); if (wasPattern || wasConstant || wasDefault || (wasNullPattern && (!isTypePattern || wasNonEmptyFallThrough))) { log.error(label.pos(), Errors.FlowsThroughToPattern); } wasPattern = true; wasTypePattern = isTypePattern; } } boolean completesNormally = c.caseKind == CaseTree.CaseKind.STATEMENT ? c.completesNormally : false; if (c.stats.nonEmpty()) { wasConstant = false; wasDefault = false; wasNullPattern &= completesNormally; wasPattern &= completesNormally; wasTypePattern &= completesNormally; } wasNonEmptyFallThrough = c.stats.nonEmpty() && completesNormally; } } void checkSwitchCaseLabelDominated(List cases) { List caseLabels = List.nil(); for (List l = cases; l.nonEmpty(); l = l.tail) { JCCase c = l.head; for (JCCaseLabel label : c.labels) { if (label.hasTag(DEFAULTCASELABEL) || TreeInfo.isNullCaseLabel(label)) { continue; } Type currentType = labelType(label); for (JCCaseLabel testCaseLabel : caseLabels) { Type testType = labelType(testCaseLabel); if (types.isSubtype(currentType, testType) && !currentType.hasTag(ERROR) && !testType.hasTag(ERROR)) { //the current label is potentially dominated by the existing (test) label, check: boolean dominated = false; if (label instanceof JCConstantCaseLabel) { dominated |= !(testCaseLabel instanceof JCConstantCaseLabel); } else if (label instanceof JCPatternCaseLabel patternCL && testCaseLabel instanceof JCPatternCaseLabel testPatternCaseLabel && TreeInfo.unguardedCaseLabel(testCaseLabel)) { dominated = patternDominated(testPatternCaseLabel.pat, patternCL.pat); } if (dominated) { log.error(label.pos(), Errors.PatternDominated); } } } caseLabels = caseLabels.prepend(label); } } } //where: private Type labelType(JCCaseLabel label) { return types.erasure(switch (label.getTag()) { case PATTERNCASELABEL -> ((JCPatternCaseLabel) label).pat.type; case CONSTANTCASELABEL -> types.boxedTypeOrType(((JCConstantCaseLabel) label).expr.type); default -> throw Assert.error("Unexpected tree kind: " + label.getTag()); }); } private boolean patternDominated(JCPattern existingPattern, JCPattern currentPattern) { Type existingPatternType = types.erasure(existingPattern.type); Type currentPatternType = types.erasure(currentPattern.type); if (existingPatternType.isPrimitive() ^ currentPatternType.isPrimitive()) { return false; } if (existingPatternType.isPrimitive()) { return types.isSameType(existingPatternType, currentPatternType); } else { if (!types.isSubtype(currentPatternType, existingPatternType)) { return false; } } while (existingPattern instanceof JCParenthesizedPattern parenthesized) { existingPattern = parenthesized.pattern; } while (currentPattern instanceof JCParenthesizedPattern parenthesized) { currentPattern = parenthesized.pattern; } if (currentPattern instanceof JCBindingPattern) { return existingPattern instanceof JCBindingPattern; } else if (currentPattern instanceof JCRecordPattern currentRecordPattern) { if (existingPattern instanceof JCBindingPattern) { return true; } else if (existingPattern instanceof JCRecordPattern existingRecordPattern) { List existingNested = existingRecordPattern.nested; List currentNested = currentRecordPattern.nested; if (existingNested.size() != currentNested.size()) { return false; } while (existingNested.nonEmpty()) { if (!patternDominated(existingNested.head, currentNested.head)) { return false; } existingNested = existingNested.tail; currentNested = currentNested.tail; } return true; } else { Assert.error("Unknown pattern: " + existingPattern.getTag()); } } else { Assert.error("Unknown pattern: " + currentPattern.getTag()); } return false; } /** check if a type is a subtype of Externalizable, if that is available. */ boolean isExternalizable(Type t) { try { syms.externalizableType.complete(); } catch (CompletionFailure e) { return false; } return types.isSubtype(t, syms.externalizableType); } /** * Check structure of serialization declarations. */ public void checkSerialStructure(JCClassDecl tree, ClassSymbol c) { (new SerialTypeVisitor()).visit(c, tree); } /** * This visitor will warn if a serialization-related field or * method is declared in a suspicious or incorrect way. In * particular, it will warn for cases where the runtime * serialization mechanism will silently ignore a mis-declared * entity. * * Distinguished serialization-related fields and methods: * * Methods: * * private void writeObject(ObjectOutputStream stream) throws IOException * ANY-ACCESS-MODIFIER Object writeReplace() throws ObjectStreamException * * private void readObject(ObjectInputStream stream) throws IOException, ClassNotFoundException * private void readObjectNoData() throws ObjectStreamException * ANY-ACCESS-MODIFIER Object readResolve() throws ObjectStreamException * * Fields: * * private static final long serialVersionUID * private static final ObjectStreamField[] serialPersistentFields * * Externalizable: methods defined on the interface * public void writeExternal(ObjectOutput) throws IOException * public void readExternal(ObjectInput) throws IOException */ private class SerialTypeVisitor extends ElementKindVisitor14 { SerialTypeVisitor() { this.lint = Check.this.lint; } private static final Set serialMethodNames = Collections.unmodifiableSet(new HashSet<>(Arrays.asList("writeObject", "writeReplace", "readObject", "readObjectNoData", "readResolve"))); private static final Set serialFieldNames = Collections.unmodifiableSet(new HashSet<>(Arrays.asList("serialVersionUID", "serialPersistentFields"))); // Type of serialPersistentFields private final Type OSF_TYPE = new Type.ArrayType(syms.objectStreamFieldType, syms.arrayClass); Lint lint; @Override public Void defaultAction(Element e, JCClassDecl p) { throw new IllegalArgumentException(ObjectsWrapper.requireNonNullElse(e.toString(), "")); } @Override public Void visitType(TypeElement e, JCClassDecl p) { runUnderLint(e, p, (symbol, param) -> super.visitType(symbol, param)); return null; } @Override public Void visitTypeAsClass(TypeElement e, JCClassDecl p) { // Anonymous classes filtered out by caller. ClassSymbol c = (ClassSymbol)e; checkCtorAccess(p, c); // Check for missing serialVersionUID; check *not* done // for enums or records. VarSymbol svuidSym = null; for (Symbol sym : c.members().getSymbolsByName(names.serialVersionUID)) { if (sym.kind == VAR) { svuidSym = (VarSymbol)sym; break; } } if (svuidSym == null) { log.warning(LintCategory.SERIAL, p.pos(), Warnings.MissingSVUID(c)); } // Check for serialPersistentFields to gate checks for // non-serializable non-transient instance fields boolean serialPersistentFieldsPresent = c.members() .getSymbolsByName(names.serialPersistentFields, sym -> sym.kind == VAR) .iterator() .hasNext(); // Check declarations of serialization-related methods and // fields for(Symbol el : c.getEnclosedElements()) { runUnderLint(el, p, (enclosed, tree) -> { String name = null; switch(enclosed.getKind()) { case FIELD -> { if (!serialPersistentFieldsPresent) { var flags = enclosed.flags(); if ( ((flags & TRANSIENT) == 0) && ((flags & STATIC) == 0)) { Type varType = enclosed.asType(); if (!canBeSerialized(varType)) { // Note per JLS arrays are // serializable even if the // component type is not. log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(enclosed, tree), Warnings.NonSerializableInstanceField); } else if (varType.hasTag(ARRAY)) { ArrayType arrayType = (ArrayType)varType; Type elementType = arrayType.elemtype; while (elementType.hasTag(ARRAY)) { arrayType = (ArrayType)elementType; elementType = arrayType.elemtype; } if (!canBeSerialized(elementType)) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(enclosed, tree), Warnings.NonSerializableInstanceFieldArray(elementType)); } } } } name = enclosed.getSimpleName().toString(); if (serialFieldNames.contains(name)) { VarSymbol field = (VarSymbol)enclosed; switch (name) { case "serialVersionUID" -> checkSerialVersionUID(tree, e, field); case "serialPersistentFields" -> checkSerialPersistentFields(tree, e, field); default -> throw new AssertionError(); } } } // Correctly checking the serialization-related // methods is subtle. For the methods declared to be // private or directly declared in the class, the // enclosed elements of the class can be checked in // turn. However, writeReplace and readResolve can be // declared in a superclass and inherited. Note that // the runtime lookup walks the superclass chain // looking for writeReplace/readResolve via // Class.getDeclaredMethod. This differs from calling // Elements.getAllMembers(TypeElement) as the latter // will also pull in default methods from // superinterfaces. In other words, the runtime checks // (which long predate default methods on interfaces) // do not admit the possibility of inheriting methods // this way, a difference from general inheritance. // The current implementation just checks the enclosed // elements and does not directly check the inherited // methods. If all the types are being checked this is // less of a concern; however, there are cases that // could be missed. In particular, readResolve and // writeReplace could, in principle, by inherited from // a non-serializable superclass and thus not checked // even if compiled with a serializable child class. case METHOD -> { var method = (MethodSymbol)enclosed; name = method.getSimpleName().toString(); if (serialMethodNames.contains(name)) { switch (name) { case "writeObject" -> checkWriteObject(tree, e, method); case "writeReplace" -> checkWriteReplace(tree,e, method); case "readObject" -> checkReadObject(tree,e, method); case "readObjectNoData" -> checkReadObjectNoData(tree, e, method); case "readResolve" -> checkReadResolve(tree, e, method); default -> throw new AssertionError(); } } } } }); } return null; } boolean canBeSerialized(Type type) { return type.isPrimitive() || rs.isSerializable(type); } /** * Check that Externalizable class needs a public no-arg * constructor. * * Check that a Serializable class has access to the no-arg * constructor of its first nonserializable superclass. */ private void checkCtorAccess(JCClassDecl tree, ClassSymbol c) { if (isExternalizable(c.type)) { for(var sym : c.getEnclosedElements()) { if (sym.isConstructor() && ((sym.flags() & PUBLIC) == PUBLIC)) { if (((MethodSymbol)sym).getParameters().isEmpty()) { return; } } } log.warning(LintCategory.SERIAL, tree.pos(), Warnings.ExternalizableMissingPublicNoArgCtor); } else { // Approximate access to the no-arg constructor up in // the superclass chain by checking that the // constructor is not private. This may not handle // some cross-package situations correctly. Type superClass = c.getSuperclass(); // java.lang.Object is *not* Serializable so this loop // should terminate. while (rs.isSerializable(superClass) ) { try { superClass = (Type)((TypeElement)(((DeclaredType)superClass)).asElement()).getSuperclass(); } catch(ClassCastException cce) { return ; // Don't try to recover } } // Non-Serializable superclass try { ClassSymbol supertype = ((ClassSymbol)(((DeclaredType)superClass).asElement())); for(var sym : supertype.getEnclosedElements()) { if (sym.isConstructor()) { MethodSymbol ctor = (MethodSymbol)sym; if (ctor.getParameters().isEmpty()) { if (((ctor.flags() & PRIVATE) == PRIVATE) || // Handle nested classes and implicit this$0 (supertype.getNestingKind() == NestingKind.MEMBER && ((supertype.flags() & STATIC) == 0))) log.warning(LintCategory.SERIAL, tree.pos(), Warnings.SerializableMissingAccessNoArgCtor(supertype.getQualifiedName())); } } } } catch (ClassCastException cce) { return ; // Don't try to recover } return; } } private void checkSerialVersionUID(JCClassDecl tree, Element e, VarSymbol svuid) { // To be effective, serialVersionUID must be marked static // and final, but private is recommended. But alas, in // practice there are many non-private serialVersionUID // fields. if ((svuid.flags() & (STATIC | FINAL)) != (STATIC | FINAL)) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(svuid, tree), Warnings.ImproperSVUID((Symbol)e)); } // check svuid has type long if (!svuid.type.hasTag(LONG)) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(svuid, tree), Warnings.LongSVUID((Symbol)e)); } if (svuid.getConstValue() == null) log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(svuid, tree), Warnings.ConstantSVUID((Symbol)e)); } private void checkSerialPersistentFields(JCClassDecl tree, Element e, VarSymbol spf) { // To be effective, serialPersisentFields must be private, static, and final. if ((spf.flags() & (PRIVATE | STATIC | FINAL)) != (PRIVATE | STATIC | FINAL)) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(spf, tree), Warnings.ImproperSPF); } if (!types.isSameType(spf.type, OSF_TYPE)) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(spf, tree), Warnings.OSFArraySPF); } if (isExternalizable((Type)(e.asType()))) { log.warning(LintCategory.SERIAL, tree.pos(), Warnings.IneffectualSerialFieldExternalizable); } // Warn if serialPersistentFields is initialized to a // literal null. JCTree spfDecl = TreeInfo.declarationFor(spf, tree); if (spfDecl != null && spfDecl.getTag() == VARDEF) { JCVariableDecl variableDef = (JCVariableDecl) spfDecl; JCExpression initExpr = variableDef.init; if (initExpr != null && TreeInfo.isNull(initExpr)) { log.warning(LintCategory.SERIAL, initExpr.pos(), Warnings.SPFNullInit); } } } private void checkWriteObject(JCClassDecl tree, Element e, MethodSymbol method) { // The "synchronized" modifier is seen in the wild on // readObject and writeObject methods and is generally // innocuous. // private void writeObject(ObjectOutputStream stream) throws IOException checkPrivateNonStaticMethod(tree, method); checkReturnType(tree, e, method, syms.voidType); checkOneArg(tree, e, method, syms.objectOutputStreamType); checkExceptions(tree, e, method, syms.ioExceptionType); checkExternalizable(tree, e, method); } private void checkWriteReplace(JCClassDecl tree, Element e, MethodSymbol method) { // ANY-ACCESS-MODIFIER Object writeReplace() throws // ObjectStreamException // Excluding abstract, could have a more complicated // rule based on abstract-ness of the class checkConcreteInstanceMethod(tree, e, method); checkReturnType(tree, e, method, syms.objectType); checkNoArgs(tree, e, method); checkExceptions(tree, e, method, syms.objectStreamExceptionType); } private void checkReadObject(JCClassDecl tree, Element e, MethodSymbol method) { // The "synchronized" modifier is seen in the wild on // readObject and writeObject methods and is generally // innocuous. // private void readObject(ObjectInputStream stream) // throws IOException, ClassNotFoundException checkPrivateNonStaticMethod(tree, method); checkReturnType(tree, e, method, syms.voidType); checkOneArg(tree, e, method, syms.objectInputStreamType); checkExceptions(tree, e, method, syms.ioExceptionType, syms.classNotFoundExceptionType); checkExternalizable(tree, e, method); } private void checkReadObjectNoData(JCClassDecl tree, Element e, MethodSymbol method) { // private void readObjectNoData() throws ObjectStreamException checkPrivateNonStaticMethod(tree, method); checkReturnType(tree, e, method, syms.voidType); checkNoArgs(tree, e, method); checkExceptions(tree, e, method, syms.objectStreamExceptionType); checkExternalizable(tree, e, method); } private void checkReadResolve(JCClassDecl tree, Element e, MethodSymbol method) { // ANY-ACCESS-MODIFIER Object readResolve() // throws ObjectStreamException // Excluding abstract, could have a more complicated // rule based on abstract-ness of the class checkConcreteInstanceMethod(tree, e, method); checkReturnType(tree,e, method, syms.objectType); checkNoArgs(tree, e, method); checkExceptions(tree, e, method, syms.objectStreamExceptionType); } void checkPrivateNonStaticMethod(JCClassDecl tree, MethodSymbol method) { var flags = method.flags(); if ((flags & PRIVATE) == 0) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(method, tree), Warnings.SerialMethodNotPrivate(method.getSimpleName())); } if ((flags & STATIC) != 0) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(method, tree), Warnings.SerialMethodStatic(method.getSimpleName())); } } /** * Per section 1.12 "Serialization of Enum Constants" of * the serialization specification, due to the special * serialization handling of enums, any writeObject, * readObject, writeReplace, and readResolve methods are * ignored as are serialPersistentFields and * serialVersionUID fields. */ @Override public Void visitTypeAsEnum(TypeElement e, JCClassDecl p) { for(Element el : e.getEnclosedElements()) { runUnderLint(el, p, (enclosed, tree) -> { String name = enclosed.getSimpleName().toString(); switch(enclosed.getKind()) { case FIELD -> { if (serialFieldNames.contains(name)) { log.warning(LintCategory.SERIAL, tree.pos(), Warnings.IneffectualSerialFieldEnum(name)); } } case METHOD -> { if (serialMethodNames.contains(name)) { log.warning(LintCategory.SERIAL, tree.pos(), Warnings.IneffectualSerialMethodEnum(name)); } } } }); } return null; } /** * Most serialization-related fields and methods on interfaces * are ineffectual or problematic. */ @Override public Void visitTypeAsInterface(TypeElement e, JCClassDecl p) { for(Element el : e.getEnclosedElements()) { runUnderLint(el, p, (enclosed, tree) -> { String name = null; switch(enclosed.getKind()) { case FIELD -> { var field = (VarSymbol)enclosed; name = field.getSimpleName().toString(); switch(name) { case "serialPersistentFields" -> { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(field, tree), Warnings.IneffectualSerialFieldInterface); } case "serialVersionUID" -> { checkSerialVersionUID(tree, e, field); } } } case METHOD -> { var method = (MethodSymbol)enclosed; name = enclosed.getSimpleName().toString(); if (serialMethodNames.contains(name)) { switch (name) { case "readObject", "readObjectNoData", "writeObject" -> checkPrivateMethod(tree, e, method); case "writeReplace", "readResolve" -> checkDefaultIneffective(tree, e, method); default -> throw new AssertionError(); } } } } }); } return null; } private void checkPrivateMethod(JCClassDecl tree, Element e, MethodSymbol method) { if ((method.flags() & PRIVATE) == 0) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(method, tree), Warnings.NonPrivateMethodWeakerAccess); } } private void checkDefaultIneffective(JCClassDecl tree, Element e, MethodSymbol method) { if ((method.flags() & DEFAULT) == DEFAULT) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(method, tree), Warnings.DefaultIneffective); } } @Override public Void visitTypeAsAnnotationType(TypeElement e, JCClassDecl p) { // Per the JLS, annotation types are not serializeable return null; } /** * From the Java Object Serialization Specification, 1.13 * Serialization of Records: * * "The process by which record objects are serialized or * externalized cannot be customized; any class-specific * writeObject, readObject, readObjectNoData, writeExternal, * and readExternal methods defined by record classes are * ignored during serialization and deserialization. However, * a substitute object to be serialized or a designate * replacement may be specified, by the writeReplace and * readResolve methods, respectively. Any * serialPersistentFields field declaration is * ignored. Documenting serializable fields and data for * record classes is unnecessary, since there is no variation * in the serial form, other than whether a substitute or * replacement object is used. The serialVersionUID of a * record class is 0L unless explicitly declared. The * requirement for matching serialVersionUID values is waived * for record classes." */ @Override public Void visitTypeAsRecord(TypeElement e, JCClassDecl p) { for(Element el : e.getEnclosedElements()) { runUnderLint(el, p, (enclosed, tree) -> { String name = enclosed.getSimpleName().toString(); switch(enclosed.getKind()) { case FIELD -> { switch(name) { case "serialPersistentFields" -> { log.warning(LintCategory.SERIAL, tree.pos(), Warnings.IneffectualSerialFieldRecord); } case "serialVersionUID" -> { // Could generate additional warning that // svuid value is not checked to match for // records. checkSerialVersionUID(tree, e, (VarSymbol)enclosed); } } } case METHOD -> { var method = (MethodSymbol)enclosed; switch(name) { case "writeReplace" -> checkWriteReplace(tree, e, method); case "readResolve" -> checkReadResolve(tree, e, method); default -> { if (serialMethodNames.contains(name)) { log.warning(LintCategory.SERIAL, tree.pos(), Warnings.IneffectualSerialMethodRecord(name)); } } } } } }); } return null; } void checkConcreteInstanceMethod(JCClassDecl tree, Element enclosing, MethodSymbol method) { if ((method.flags() & (STATIC | ABSTRACT)) != 0) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(method, tree), Warnings.SerialConcreteInstanceMethod(method.getSimpleName())); } } private void checkReturnType(JCClassDecl tree, Element enclosing, MethodSymbol method, Type expectedReturnType) { // Note: there may be complications checking writeReplace // and readResolve since they return Object and could, in // principle, have covariant overrides and any synthetic // bridge method would not be represented here for // checking. Type rtype = method.getReturnType(); if (!types.isSameType(expectedReturnType, rtype)) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(method, tree), Warnings.SerialMethodUnexpectedReturnType(method.getSimpleName(), rtype, expectedReturnType)); } } private void checkOneArg(JCClassDecl tree, Element enclosing, MethodSymbol method, Type expectedType) { String name = method.getSimpleName().toString(); var parameters= method.getParameters(); if (parameters.size() != 1) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(method, tree), Warnings.SerialMethodOneArg(method.getSimpleName(), parameters.size())); return; } Type parameterType = parameters.get(0).asType(); if (!types.isSameType(parameterType, expectedType)) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(method, tree), Warnings.SerialMethodParameterType(method.getSimpleName(), expectedType, parameterType)); } } private void checkNoArgs(JCClassDecl tree, Element enclosing, MethodSymbol method) { var parameters = method.getParameters(); if (!parameters.isEmpty()) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(parameters.get(0), tree), Warnings.SerialMethodNoArgs(method.getSimpleName())); } } private void checkExternalizable(JCClassDecl tree, Element enclosing, MethodSymbol method) { // If the enclosing class is externalizable, warn for the method if (isExternalizable((Type)enclosing.asType())) { log.warning(LintCategory.SERIAL, tree.pos(), Warnings.IneffectualSerialMethodExternalizable(method.getSimpleName())); } return; } private void checkExceptions(JCClassDecl tree, Element enclosing, MethodSymbol method, Type... declaredExceptions) { for (Type thrownType: method.getThrownTypes()) { // For each exception in the throws clause of the // method, if not an Error and not a RuntimeException, // check if the exception is a subtype of a declared // exception from the throws clause of the // serialization method in question. if (types.isSubtype(thrownType, syms.runtimeExceptionType) || types.isSubtype(thrownType, syms.errorType) ) { continue; } else { boolean declared = false; for (Type declaredException : declaredExceptions) { if (types.isSubtype(thrownType, declaredException)) { declared = true; continue; } } if (!declared) { log.warning(LintCategory.SERIAL, TreeInfo.diagnosticPositionFor(method, tree), Warnings.SerialMethodUnexpectedException(method.getSimpleName(), thrownType)); } } } return; } private Void runUnderLint(E symbol, JCClassDecl p, BiConsumer task) { Lint prevLint = lint; try { lint = lint.augment((Symbol) symbol); if (lint.isEnabled(LintCategory.SERIAL)) { task.accept(symbol, p); } return null; } finally { lint = prevLint; } } } }




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