--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,4941 @@
+/*
+ * Copyright (c) 2003, 2017, 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.code;
+
+import java.lang.ref.SoftReference;
+import java.util.HashSet;
+import java.util.HashMap;
+import java.util.Locale;
+import java.util.Map;
+import java.util.Optional;
+import java.util.Set;
+import java.util.WeakHashMap;
+import java.util.function.BiPredicate;
+import java.util.function.Function;
+import java.util.stream.Collector;
+
+import javax.tools.JavaFileObject;
+
+import com.sun.tools.javac.code.Attribute.RetentionPolicy;
+import com.sun.tools.javac.code.Lint.LintCategory;
+import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
+import com.sun.tools.javac.code.TypeMetadata.Entry.Kind;
+import com.sun.tools.javac.comp.AttrContext;
+import com.sun.tools.javac.comp.Check;
+import com.sun.tools.javac.comp.Enter;
+import com.sun.tools.javac.comp.Env;
+import com.sun.tools.javac.util.*;
+
+import static com.sun.tools.javac.code.BoundKind.*;
+import static com.sun.tools.javac.code.Flags.*;
+import static com.sun.tools.javac.code.Kinds.Kind.*;
+import static com.sun.tools.javac.code.Scope.*;
+import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
+import static com.sun.tools.javac.code.Symbol.*;
+import static com.sun.tools.javac.code.Type.*;
+import static com.sun.tools.javac.code.TypeTag.*;
+import static com.sun.tools.javac.jvm.ClassFile.externalize;
+import com.sun.tools.javac.resources.CompilerProperties.Fragments;
+
+/**
+ * Utility class containing various operations on types.
+ *
+ * <p>Unless other names are more illustrative, the following naming
+ * conventions should be observed in this file:
+ *
+ * <dl>
+ * <dt>t</dt>
+ * <dd>If the first argument to an operation is a type, it should be named t.</dd>
+ * <dt>s</dt>
+ * <dd>Similarly, if the second argument to an operation is a type, it should be named s.</dd>
+ * <dt>ts</dt>
+ * <dd>If an operations takes a list of types, the first should be named ts.</dd>
+ * <dt>ss</dt>
+ * <dd>A second list of types should be named ss.</dd>
+ * </dl>
+ *
+ * <p><b>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.</b>
+ */
+public class Types {
+ protected static final Context.Key<Types> typesKey = new Context.Key<>();
+
+ final Symtab syms;
+ final JavacMessages messages;
+ final Names names;
+ final boolean allowObjectToPrimitiveCast;
+ final boolean allowDefaultMethods;
+ final boolean mapCapturesToBounds;
+ final Check chk;
+ final Enter enter;
+ JCDiagnostic.Factory diags;
+ List<Warner> warnStack = List.nil();
+ final Name capturedName;
+ private final FunctionDescriptorLookupError functionDescriptorLookupError;
+
+ public final Warner noWarnings;
+
+ // <editor-fold defaultstate="collapsed" desc="Instantiating">
+ public static Types instance(Context context) {
+ Types instance = context.get(typesKey);
+ if (instance == null)
+ instance = new Types(context);
+ return instance;
+ }
+
+ protected Types(Context context) {
+ context.put(typesKey, this);
+ syms = Symtab.instance(context);
+ names = Names.instance(context);
+ Source source = Source.instance(context);
+ allowObjectToPrimitiveCast = source.allowObjectToPrimitiveCast();
+ allowDefaultMethods = source.allowDefaultMethods();
+ mapCapturesToBounds = source.mapCapturesToBounds();
+ chk = Check.instance(context);
+ enter = Enter.instance(context);
+ capturedName = names.fromString("<captured wildcard>");
+ messages = JavacMessages.instance(context);
+ diags = JCDiagnostic.Factory.instance(context);
+ functionDescriptorLookupError = new FunctionDescriptorLookupError();
+ noWarnings = new Warner(null);
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="bounds">
+ /**
+ * Get a wildcard's upper bound, returning non-wildcards unchanged.
+ * @param t a type argument, either a wildcard or a type
+ */
+ public Type wildUpperBound(Type t) {
+ if (t.hasTag(WILDCARD)) {
+ WildcardType w = (WildcardType) t;
+ if (w.isSuperBound())
+ return w.bound == null ? syms.objectType : w.bound.bound;
+ else
+ return wildUpperBound(w.type);
+ }
+ else return t;
+ }
+
+ /**
+ * Get a capture variable's upper bound, returning other types unchanged.
+ * @param t a type
+ */
+ public Type cvarUpperBound(Type t) {
+ if (t.hasTag(TYPEVAR)) {
+ TypeVar v = (TypeVar) t;
+ return v.isCaptured() ? cvarUpperBound(v.bound) : v;
+ }
+ else return t;
+ }
+
+ /**
+ * Get a wildcard's lower bound, returning non-wildcards unchanged.
+ * @param t a type argument, either a wildcard or a type
+ */
+ public Type wildLowerBound(Type t) {
+ if (t.hasTag(WILDCARD)) {
+ WildcardType w = (WildcardType) t;
+ return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type);
+ }
+ else return t;
+ }
+
+ /**
+ * Get a capture variable's lower bound, returning other types unchanged.
+ * @param t a type
+ */
+ public Type cvarLowerBound(Type t) {
+ if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) {
+ return cvarLowerBound(t.getLowerBound());
+ }
+ else return t;
+ }
+
+ /**
+ * Recursively skip type-variables until a class/array type is found; capture conversion is then
+ * (optionally) applied to the resulting type. This is useful for i.e. computing a site that is
+ * suitable for a method lookup.
+ */
+ public Type skipTypeVars(Type site, boolean capture) {
+ while (site.hasTag(TYPEVAR)) {
+ site = site.getUpperBound();
+ }
+ return capture ? capture(site) : site;
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="isUnbounded">
+ /**
+ * Checks that all the arguments to a class are unbounded
+ * wildcards or something else that doesn't make any restrictions
+ * on the arguments. If a class isUnbounded, a raw super- or
+ * subclass can be cast to it without a warning.
+ * @param t a type
+ * @return true iff the given type is unbounded or raw
+ */
+ public boolean isUnbounded(Type t) {
+ return isUnbounded.visit(t);
+ }
+ // where
+ private final UnaryVisitor<Boolean> isUnbounded = new UnaryVisitor<Boolean>() {
+
+ public Boolean visitType(Type t, Void ignored) {
+ return true;
+ }
+
+ @Override
+ public Boolean visitClassType(ClassType t, Void ignored) {
+ List<Type> parms = t.tsym.type.allparams();
+ List<Type> args = t.allparams();
+ while (parms.nonEmpty()) {
+ WildcardType unb = new WildcardType(syms.objectType,
+ BoundKind.UNBOUND,
+ syms.boundClass,
+ (TypeVar)parms.head);
+ if (!containsType(args.head, unb))
+ return false;
+ parms = parms.tail;
+ args = args.tail;
+ }
+ return true;
+ }
+ };
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="asSub">
+ /**
+ * Return the least specific subtype of t that starts with symbol
+ * sym. If none exists, return null. The least specific subtype
+ * is determined as follows:
+ *
+ * <p>If there is exactly one parameterized instance of sym that is a
+ * subtype of t, that parameterized instance is returned.<br>
+ * Otherwise, if the plain type or raw type `sym' is a subtype of
+ * type t, the type `sym' itself is returned. Otherwise, null is
+ * returned.
+ */
+ public Type asSub(Type t, Symbol sym) {
+ return asSub.visit(t, sym);
+ }
+ // where
+ private final SimpleVisitor<Type,Symbol> asSub = new SimpleVisitor<Type,Symbol>() {
+
+ public Type visitType(Type t, Symbol sym) {
+ return null;
+ }
+
+ @Override
+ public Type visitClassType(ClassType t, Symbol sym) {
+ if (t.tsym == sym)
+ return t;
+ Type base = asSuper(sym.type, t.tsym);
+ if (base == null)
+ return null;
+ ListBuffer<Type> from = new ListBuffer<>();
+ ListBuffer<Type> to = new ListBuffer<>();
+ try {
+ adapt(base, t, from, to);
+ } catch (AdaptFailure ex) {
+ return null;
+ }
+ Type res = subst(sym.type, from.toList(), to.toList());
+ if (!isSubtype(res, t))
+ return null;
+ ListBuffer<Type> openVars = new ListBuffer<>();
+ for (List<Type> l = sym.type.allparams();
+ l.nonEmpty(); l = l.tail)
+ if (res.contains(l.head) && !t.contains(l.head))
+ openVars.append(l.head);
+ if (openVars.nonEmpty()) {
+ if (t.isRaw()) {
+ // The subtype of a raw type is raw
+ res = erasure(res);
+ } else {
+ // Unbound type arguments default to ?
+ List<Type> opens = openVars.toList();
+ ListBuffer<Type> qs = new ListBuffer<>();
+ for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
+ qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND,
+ syms.boundClass, (TypeVar) iter.head));
+ }
+ res = subst(res, opens, qs.toList());
+ }
+ }
+ return res;
+ }
+
+ @Override
+ public Type visitErrorType(ErrorType t, Symbol sym) {
+ return t;
+ }
+ };
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="isConvertible">
+ /**
+ * Is t a subtype of or convertible via boxing/unboxing
+ * conversion to s?
+ */
+ public boolean isConvertible(Type t, Type s, Warner warn) {
+ if (t.hasTag(ERROR)) {
+ return true;
+ }
+ boolean tPrimitive = t.isPrimitive();
+ boolean sPrimitive = s.isPrimitive();
+ if (tPrimitive == sPrimitive) {
+ return isSubtypeUnchecked(t, s, warn);
+ }
+ boolean tUndet = t.hasTag(UNDETVAR);
+ boolean sUndet = s.hasTag(UNDETVAR);
+
+ if (tUndet || sUndet) {
+ return tUndet ?
+ isSubtype(t, boxedTypeOrType(s)) :
+ isSubtype(boxedTypeOrType(t), s);
+ }
+
+ return tPrimitive
+ ? isSubtype(boxedClass(t).type, s)
+ : isSubtype(unboxedType(t), s);
+ }
+
+ /**
+ * Is t a subtype of or convertible via boxing/unboxing
+ * conversions to s?
+ */
+ public boolean isConvertible(Type t, Type s) {
+ return isConvertible(t, s, noWarnings);
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="findSam">
+
+ /**
+ * Exception used to report a function descriptor lookup failure. The exception
+ * wraps a diagnostic that can be used to generate more details error
+ * messages.
+ */
+ public static class FunctionDescriptorLookupError extends RuntimeException {
+ private static final long serialVersionUID = 0;
+
+ JCDiagnostic diagnostic;
+
+ FunctionDescriptorLookupError() {
+ this.diagnostic = null;
+ }
+
+ FunctionDescriptorLookupError setMessage(JCDiagnostic diag) {
+ this.diagnostic = diag;
+ return this;
+ }
+
+ public JCDiagnostic getDiagnostic() {
+ return diagnostic;
+ }
+ }
+
+ /**
+ * A cache that keeps track of function descriptors associated with given
+ * functional interfaces.
+ */
+ class DescriptorCache {
+
+ private WeakHashMap<TypeSymbol, Entry> _map = new WeakHashMap<>();
+
+ class FunctionDescriptor {
+ Symbol descSym;
+
+ FunctionDescriptor(Symbol descSym) {
+ this.descSym = descSym;
+ }
+
+ public Symbol getSymbol() {
+ return descSym;
+ }
+
+ public Type getType(Type site) {
+ site = removeWildcards(site);
+ if (!chk.checkValidGenericType(site)) {
+ //if the inferred functional interface type is not well-formed,
+ //or if it's not a subtype of the original target, issue an error
+ throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
+ }
+ return memberType(site, descSym);
+ }
+ }
+
+ class Entry {
+ final FunctionDescriptor cachedDescRes;
+ final int prevMark;
+
+ public Entry(FunctionDescriptor cachedDescRes,
+ int prevMark) {
+ this.cachedDescRes = cachedDescRes;
+ this.prevMark = prevMark;
+ }
+
+ boolean matches(int mark) {
+ return this.prevMark == mark;
+ }
+ }
+
+ FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
+ Entry e = _map.get(origin);
+ CompoundScope members = membersClosure(origin.type, false);
+ if (e == null ||
+ !e.matches(members.getMark())) {
+ FunctionDescriptor descRes = findDescriptorInternal(origin, members);
+ _map.put(origin, new Entry(descRes, members.getMark()));
+ return descRes;
+ }
+ else {
+ return e.cachedDescRes;
+ }
+ }
+
+ /**
+ * Compute the function descriptor associated with a given functional interface
+ */
+ public FunctionDescriptor findDescriptorInternal(TypeSymbol origin,
+ CompoundScope membersCache) throws FunctionDescriptorLookupError {
+ if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0) {
+ //t must be an interface
+ throw failure("not.a.functional.intf", origin);
+ }
+
+ final ListBuffer<Symbol> abstracts = new ListBuffer<>();
+ for (Symbol sym : membersCache.getSymbols(new DescriptorFilter(origin))) {
+ Type mtype = memberType(origin.type, sym);
+ if (abstracts.isEmpty()) {
+ abstracts.append(sym);
+ } else if ((sym.name == abstracts.first().name &&
+ overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
+ if (!abstracts.stream().filter(msym -> msym.owner.isSubClass(sym.enclClass(), Types.this))
+ .map(msym -> memberType(origin.type, msym))
+ .anyMatch(abstractMType -> isSubSignature(abstractMType, mtype))) {
+ abstracts.append(sym);
+ }
+ } else {
+ //the target method(s) should be the only abstract members of t
+ throw failure("not.a.functional.intf.1", origin,
+ diags.fragment(Fragments.IncompatibleAbstracts(Kinds.kindName(origin), origin)));
+ }
+ }
+ if (abstracts.isEmpty()) {
+ //t must define a suitable non-generic method
+ throw failure("not.a.functional.intf.1", origin,
+ diags.fragment(Fragments.NoAbstracts(Kinds.kindName(origin), origin)));
+ } else if (abstracts.size() == 1) {
+ return new FunctionDescriptor(abstracts.first());
+ } else { // size > 1
+ FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
+ if (descRes == null) {
+ //we can get here if the functional interface is ill-formed
+ ListBuffer<JCDiagnostic> descriptors = new ListBuffer<>();
+ for (Symbol desc : abstracts) {
+ String key = desc.type.getThrownTypes().nonEmpty() ?
+ "descriptor.throws" : "descriptor";
+ descriptors.append(diags.fragment(key, desc.name,
+ desc.type.getParameterTypes(),
+ desc.type.getReturnType(),
+ desc.type.getThrownTypes()));
+ }
+ JCDiagnostic msg =
+ diags.fragment(Fragments.IncompatibleDescsInFunctionalIntf(Kinds.kindName(origin),
+ origin));
+ JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
+ new JCDiagnostic.MultilineDiagnostic(msg, descriptors.toList());
+ throw failure(incompatibleDescriptors);
+ }
+ return descRes;
+ }
+ }
+
+ /**
+ * Compute a synthetic type for the target descriptor given a list
+ * of override-equivalent methods in the functional interface type.
+ * The resulting method type is a method type that is override-equivalent
+ * and return-type substitutable with each method in the original list.
+ */
+ private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List<Symbol> methodSyms) {
+ return mergeAbstracts(methodSyms, origin.type, false)
+ .map(bestSoFar -> new FunctionDescriptor(bestSoFar.baseSymbol()) {
+ @Override
+ public Type getType(Type origin) {
+ Type mt = memberType(origin, getSymbol());
+ return createMethodTypeWithThrown(mt, bestSoFar.type.getThrownTypes());
+ }
+ }).orElse(null);
+ }
+
+ FunctionDescriptorLookupError failure(String msg, Object... args) {
+ return failure(diags.fragment(msg, args));
+ }
+
+ FunctionDescriptorLookupError failure(JCDiagnostic diag) {
+ return functionDescriptorLookupError.setMessage(diag);
+ }
+ }
+
+ private DescriptorCache descCache = new DescriptorCache();
+
+ /**
+ * Find the method descriptor associated to this class symbol - if the
+ * symbol 'origin' is not a functional interface, an exception is thrown.
+ */
+ public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
+ return descCache.get(origin).getSymbol();
+ }
+
+ /**
+ * Find the type of the method descriptor associated to this class symbol -
+ * if the symbol 'origin' is not a functional interface, an exception is thrown.
+ */
+ public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
+ return descCache.get(origin.tsym).getType(origin);
+ }
+
+ /**
+ * Is given type a functional interface?
+ */
+ public boolean isFunctionalInterface(TypeSymbol tsym) {
+ try {
+ findDescriptorSymbol(tsym);
+ return true;
+ } catch (FunctionDescriptorLookupError ex) {
+ return false;
+ }
+ }
+
+ public boolean isFunctionalInterface(Type site) {
+ try {
+ findDescriptorType(site);
+ return true;
+ } catch (FunctionDescriptorLookupError ex) {
+ return false;
+ }
+ }
+
+ public Type removeWildcards(Type site) {
+ if (site.getTypeArguments().stream().anyMatch(t -> t.hasTag(WILDCARD))) {
+ //compute non-wildcard parameterization - JLS 9.9
+ List<Type> actuals = site.getTypeArguments();
+ List<Type> formals = site.tsym.type.getTypeArguments();
+ ListBuffer<Type> targs = new ListBuffer<>();
+ for (Type formal : formals) {
+ Type actual = actuals.head;
+ Type bound = formal.getUpperBound();
+ if (actuals.head.hasTag(WILDCARD)) {
+ WildcardType wt = (WildcardType)actual;
+ //check that bound does not contain other formals
+ if (bound.containsAny(formals)) {
+ targs.add(wt.type);
+ } else {
+ //compute new type-argument based on declared bound and wildcard bound
+ switch (wt.kind) {
+ case UNBOUND:
+ targs.add(bound);
+ break;
+ case EXTENDS:
+ targs.add(glb(bound, wt.type));
+ break;
+ case SUPER:
+ targs.add(wt.type);
+ break;
+ default:
+ Assert.error("Cannot get here!");
+ }
+ }
+ } else {
+ //not a wildcard - the new type argument remains unchanged
+ targs.add(actual);
+ }
+ actuals = actuals.tail;
+ }
+ return subst(site.tsym.type, formals, targs.toList());
+ } else {
+ return site;
+ }
+ }
+
+ /**
+ * Create a symbol for a class that implements a given functional interface
+ * and overrides its functional descriptor. This routine is used for two
+ * main purposes: (i) checking well-formedness of a functional interface;
+ * (ii) perform functional interface bridge calculation.
+ */
+ public ClassSymbol makeFunctionalInterfaceClass(Env<AttrContext> env, Name name, List<Type> targets, long cflags) {
+ if (targets.isEmpty()) {
+ return null;
+ }
+ Symbol descSym = findDescriptorSymbol(targets.head.tsym);
+ Type descType = findDescriptorType(targets.head);
+ ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass());
+ csym.completer = Completer.NULL_COMPLETER;
+ csym.members_field = WriteableScope.create(csym);
+ MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym);
+ csym.members_field.enter(instDescSym);
+ Type.ClassType ctype = new Type.ClassType(Type.noType, List.nil(), csym);
+ ctype.supertype_field = syms.objectType;
+ ctype.interfaces_field = targets;
+ csym.type = ctype;
+ csym.sourcefile = ((ClassSymbol)csym.owner).sourcefile;
+ return csym;
+ }
+
+ /**
+ * Find the minimal set of methods that are overridden by the functional
+ * descriptor in 'origin'. All returned methods are assumed to have different
+ * erased signatures.
+ */
+ public List<Symbol> functionalInterfaceBridges(TypeSymbol origin) {
+ Assert.check(isFunctionalInterface(origin));
+ Symbol descSym = findDescriptorSymbol(origin);
+ CompoundScope members = membersClosure(origin.type, false);
+ ListBuffer<Symbol> overridden = new ListBuffer<>();
+ outer: for (Symbol m2 : members.getSymbolsByName(descSym.name, bridgeFilter)) {
+ if (m2 == descSym) continue;
+ else if (descSym.overrides(m2, origin, Types.this, false)) {
+ for (Symbol m3 : overridden) {
+ if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) ||
+ (m3.overrides(m2, origin, Types.this, false) &&
+ (pendingBridges((ClassSymbol)origin, m3.enclClass()) ||
+ (((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) {
+ continue outer;
+ }
+ }
+ overridden.add(m2);
+ }
+ }
+ return overridden.toList();
+ }
+ //where
+ private Filter<Symbol> bridgeFilter = new Filter<Symbol>() {
+ public boolean accepts(Symbol t) {
+ return t.kind == MTH &&
+ t.name != names.init &&
+ t.name != names.clinit &&
+ (t.flags() & SYNTHETIC) == 0;
+ }
+ };
+ private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) {
+ //a symbol will be completed from a classfile if (a) symbol has
+ //an associated file object with CLASS kind and (b) the symbol has
+ //not been entered
+ if (origin.classfile != null &&
+ origin.classfile.getKind() == JavaFileObject.Kind.CLASS &&
+ enter.getEnv(origin) == null) {
+ return false;
+ }
+ if (origin == s) {
+ return true;
+ }
+ for (Type t : interfaces(origin.type)) {
+ if (pendingBridges((ClassSymbol)t.tsym, s)) {
+ return true;
+ }
+ }
+ return false;
+ }
+ // </editor-fold>
+
+ /**
+ * Scope filter used to skip methods that should be ignored (such as methods
+ * overridden by j.l.Object) during function interface conversion interface check
+ */
+ class DescriptorFilter implements Filter<Symbol> {
+
+ TypeSymbol origin;
+
+ DescriptorFilter(TypeSymbol origin) {
+ this.origin = origin;
+ }
+
+ @Override
+ public boolean accepts(Symbol sym) {
+ return sym.kind == MTH &&
+ (sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
+ !overridesObjectMethod(origin, sym) &&
+ (interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
+ }
+ }
+
+ // <editor-fold defaultstate="collapsed" desc="isSubtype">
+ /**
+ * Is t an unchecked subtype of s?
+ */
+ public boolean isSubtypeUnchecked(Type t, Type s) {
+ return isSubtypeUnchecked(t, s, noWarnings);
+ }
+ /**
+ * Is t an unchecked subtype of s?
+ */
+ public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
+ boolean result = isSubtypeUncheckedInternal(t, s, true, warn);
+ if (result) {
+ checkUnsafeVarargsConversion(t, s, warn);
+ }
+ return result;
+ }
+ //where
+ private boolean isSubtypeUncheckedInternal(Type t, Type s, boolean capture, Warner warn) {
+ if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
+ if (((ArrayType)t).elemtype.isPrimitive()) {
+ return isSameType(elemtype(t), elemtype(s));
+ } else {
+ return isSubtypeUncheckedInternal(elemtype(t), elemtype(s), false, warn);
+ }
+ } else if (isSubtype(t, s, capture)) {
+ return true;
+ } else if (t.hasTag(TYPEVAR)) {
+ return isSubtypeUncheckedInternal(t.getUpperBound(), s, false, warn);
+ } else if (!s.isRaw()) {
+ Type t2 = asSuper(t, s.tsym);
+ if (t2 != null && t2.isRaw()) {
+ if (isReifiable(s)) {
+ warn.silentWarn(LintCategory.UNCHECKED);
+ } else {
+ warn.warn(LintCategory.UNCHECKED);
+ }
+ return true;
+ }
+ }
+ return false;
+ }
+
+ private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
+ if (!t.hasTag(ARRAY) || isReifiable(t)) {
+ return;
+ }
+ ArrayType from = (ArrayType)t;
+ boolean shouldWarn = false;
+ switch (s.getTag()) {
+ case ARRAY:
+ ArrayType to = (ArrayType)s;
+ shouldWarn = from.isVarargs() &&
+ !to.isVarargs() &&
+ !isReifiable(from);
+ break;
+ case CLASS:
+ shouldWarn = from.isVarargs();
+ break;
+ }
+ if (shouldWarn) {
+ warn.warn(LintCategory.VARARGS);
+ }
+ }
+
+ /**
+ * Is t a subtype of s?<br>
+ * (not defined for Method and ForAll types)
+ */
+ final public boolean isSubtype(Type t, Type s) {
+ return isSubtype(t, s, true);
+ }
+ final public boolean isSubtypeNoCapture(Type t, Type s) {
+ return isSubtype(t, s, false);
+ }
+ public boolean isSubtype(Type t, Type s, boolean capture) {
+ if (t.equalsIgnoreMetadata(s))
+ return true;
+ if (s.isPartial())
+ return isSuperType(s, t);
+
+ if (s.isCompound()) {
+ for (Type s2 : interfaces(s).prepend(supertype(s))) {
+ if (!isSubtype(t, s2, capture))
+ return false;
+ }
+ return true;
+ }
+
+ // Generally, if 's' is a lower-bounded type variable, recur on lower bound; but
+ // for inference variables and intersections, we need to keep 's'
+ // (see JLS 4.10.2 for intersections and 18.2.3 for inference vars)
+ if (!t.hasTag(UNDETVAR) && !t.isCompound()) {
+ // TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s
+ Type lower = cvarLowerBound(wildLowerBound(s));
+ if (s != lower && !lower.hasTag(BOT))
+ return isSubtype(capture ? capture(t) : t, lower, false);
+ }
+
+ return isSubtype.visit(capture ? capture(t) : t, s);
+ }
+ // where
+ private TypeRelation isSubtype = new TypeRelation()
+ {
+ @Override
+ public Boolean visitType(Type t, Type s) {
+ switch (t.getTag()) {
+ case BYTE:
+ return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
+ case CHAR:
+ return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
+ case SHORT: case INT: case LONG:
+ case FLOAT: case DOUBLE:
+ return t.getTag().isSubRangeOf(s.getTag());
+ case BOOLEAN: case VOID:
+ return t.hasTag(s.getTag());
+ case TYPEVAR:
+ return isSubtypeNoCapture(t.getUpperBound(), s);
+ case BOT:
+ return
+ s.hasTag(BOT) || s.hasTag(CLASS) ||
+ s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
+ case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
+ case NONE:
+ return false;
+ default:
+ throw new AssertionError("isSubtype " + t.getTag());
+ }
+ }
+
+ private Set<TypePair> cache = new HashSet<>();
+
+ private boolean containsTypeRecursive(Type t, Type s) {
+ TypePair pair = new TypePair(t, s);
+ if (cache.add(pair)) {
+ try {
+ return containsType(t.getTypeArguments(),
+ s.getTypeArguments());
+ } finally {
+ cache.remove(pair);
+ }
+ } else {
+ return containsType(t.getTypeArguments(),
+ rewriteSupers(s).getTypeArguments());
+ }
+ }
+
+ private Type rewriteSupers(Type t) {
+ if (!t.isParameterized())
+ return t;
+ ListBuffer<Type> from = new ListBuffer<>();
+ ListBuffer<Type> to = new ListBuffer<>();
+ adaptSelf(t, from, to);
+ if (from.isEmpty())
+ return t;
+ ListBuffer<Type> rewrite = new ListBuffer<>();
+ boolean changed = false;
+ for (Type orig : to.toList()) {
+ Type s = rewriteSupers(orig);
+ if (s.isSuperBound() && !s.isExtendsBound()) {
+ s = new WildcardType(syms.objectType,
+ BoundKind.UNBOUND,
+ syms.boundClass,
+ s.getMetadata());
+ changed = true;
+ } else if (s != orig) {
+ s = new WildcardType(wildUpperBound(s),
+ BoundKind.EXTENDS,
+ syms.boundClass,
+ s.getMetadata());
+ changed = true;
+ }
+ rewrite.append(s);
+ }
+ if (changed)
+ return subst(t.tsym.type, from.toList(), rewrite.toList());
+ else
+ return t;
+ }
+
+ @Override
+ public Boolean visitClassType(ClassType t, Type s) {
+ Type sup = asSuper(t, s.tsym);
+ if (sup == null) return false;
+ // If t is an intersection, sup might not be a class type
+ if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s);
+ return sup.tsym == s.tsym
+ // Check type variable containment
+ && (!s.isParameterized() || containsTypeRecursive(s, sup))
+ && isSubtypeNoCapture(sup.getEnclosingType(),
+ s.getEnclosingType());
+ }
+
+ @Override
+ public Boolean visitArrayType(ArrayType t, Type s) {
+ if (s.hasTag(ARRAY)) {
+ if (t.elemtype.isPrimitive())
+ return isSameType(t.elemtype, elemtype(s));
+ else
+ return isSubtypeNoCapture(t.elemtype, elemtype(s));
+ }
+
+ if (s.hasTag(CLASS)) {
+ Name sname = s.tsym.getQualifiedName();
+ return sname == names.java_lang_Object
+ || sname == names.java_lang_Cloneable
+ || sname == names.java_io_Serializable;
+ }
+
+ return false;
+ }
+
+ @Override
+ public Boolean visitUndetVar(UndetVar t, Type s) {
+ //todo: test against origin needed? or replace with substitution?
+ if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
+ return true;
+ } else if (s.hasTag(BOT)) {
+ //if 's' is 'null' there's no instantiated type U for which
+ //U <: s (but 'null' itself, which is not a valid type)
+ return false;
+ }
+
+ t.addBound(InferenceBound.UPPER, s, Types.this);
+ return true;
+ }
+
+ @Override
+ public Boolean visitErrorType(ErrorType t, Type s) {
+ return true;
+ }
+ };
+
+ /**
+ * Is t a subtype of every type in given list `ts'?<br>
+ * (not defined for Method and ForAll types)<br>
+ * Allows unchecked conversions.
+ */
+ public boolean isSubtypeUnchecked(Type t, List<Type> ts, Warner warn) {
+ for (List<Type> l = ts; l.nonEmpty(); l = l.tail)
+ if (!isSubtypeUnchecked(t, l.head, warn))
+ return false;
+ return true;
+ }
+
+ /**
+ * Are corresponding elements of ts subtypes of ss? If lists are
+ * of different length, return false.
+ */
+ public boolean isSubtypes(List<Type> ts, List<Type> ss) {
+ while (ts.tail != null && ss.tail != null
+ /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
+ isSubtype(ts.head, ss.head)) {
+ ts = ts.tail;
+ ss = ss.tail;
+ }
+ return ts.tail == null && ss.tail == null;
+ /*inlined: ts.isEmpty() && ss.isEmpty();*/
+ }
+
+ /**
+ * Are corresponding elements of ts subtypes of ss, allowing
+ * unchecked conversions? If lists are of different length,
+ * return false.
+ **/
+ public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
+ while (ts.tail != null && ss.tail != null
+ /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
+ isSubtypeUnchecked(ts.head, ss.head, warn)) {
+ ts = ts.tail;
+ ss = ss.tail;
+ }
+ return ts.tail == null && ss.tail == null;
+ /*inlined: ts.isEmpty() && ss.isEmpty();*/
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="isSuperType">
+ /**
+ * Is t a supertype of s?
+ */
+ public boolean isSuperType(Type t, Type s) {
+ switch (t.getTag()) {
+ case ERROR:
+ return true;
+ case UNDETVAR: {
+ UndetVar undet = (UndetVar)t;
+ if (t == s ||
+ undet.qtype == s ||
+ s.hasTag(ERROR) ||
+ s.hasTag(BOT)) {
+ return true;
+ }
+ undet.addBound(InferenceBound.LOWER, s, this);
+ return true;
+ }
+ default:
+ return isSubtype(s, t);
+ }
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="isSameType">
+ /**
+ * Are corresponding elements of the lists the same type? If
+ * lists are of different length, return false.
+ */
+ public boolean isSameTypes(List<Type> ts, List<Type> ss) {
+ return isSameTypes(ts, ss, false);
+ }
+ public boolean isSameTypes(List<Type> ts, List<Type> ss, boolean strict) {
+ while (ts.tail != null && ss.tail != null
+ /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
+ isSameType(ts.head, ss.head, strict)) {
+ ts = ts.tail;
+ ss = ss.tail;
+ }
+ return ts.tail == null && ss.tail == null;
+ /*inlined: ts.isEmpty() && ss.isEmpty();*/
+ }
+
+ /**
+ * A polymorphic signature method (JLS 15.12.3) is a method that
+ * (i) is declared in the java.lang.invoke.MethodHandle/VarHandle classes;
+ * (ii) takes a single variable arity parameter;
+ * (iii) whose declared type is Object[];
+ * (iv) has any return type, Object signifying a polymorphic return type; and
+ * (v) is native.
+ */
+ public boolean isSignaturePolymorphic(MethodSymbol msym) {
+ List<Type> argtypes = msym.type.getParameterTypes();
+ return (msym.flags_field & NATIVE) != 0 &&
+ (msym.owner == syms.methodHandleType.tsym || msym.owner == syms.varHandleType.tsym) &&
+ argtypes.length() == 1 &&
+ argtypes.head.hasTag(TypeTag.ARRAY) &&
+ ((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym;
+ }
+
+ /**
+ * Is t the same type as s?
+ */
+ public boolean isSameType(Type t, Type s) {
+ return isSameType(t, s, false);
+ }
+ public boolean isSameType(Type t, Type s, boolean strict) {
+ return strict ?
+ isSameTypeStrict.visit(t, s) :
+ isSameTypeLoose.visit(t, s);
+ }
+ // where
+ abstract class SameTypeVisitor extends TypeRelation {
+
+ public Boolean visitType(Type t, Type s) {
+ if (t.equalsIgnoreMetadata(s))
+ return true;
+
+ if (s.isPartial())
+ return visit(s, t);
+
+ switch (t.getTag()) {
+ case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
+ case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
+ return t.hasTag(s.getTag());
+ case TYPEVAR: {
+ if (s.hasTag(TYPEVAR)) {
+ //type-substitution does not preserve type-var types
+ //check that type var symbols and bounds are indeed the same
+ return sameTypeVars((TypeVar)t, (TypeVar)s);
+ }
+ else {
+ //special case for s == ? super X, where upper(s) = u
+ //check that u == t, where u has been set by Type.withTypeVar
+ return s.isSuperBound() &&
+ !s.isExtendsBound() &&
+ visit(t, wildUpperBound(s));
+ }
+ }
+ default:
+ throw new AssertionError("isSameType " + t.getTag());
+ }
+ }
+
+ abstract boolean sameTypeVars(TypeVar tv1, TypeVar tv2);
+
+ @Override
+ public Boolean visitWildcardType(WildcardType t, Type s) {
+ if (!s.hasTag(WILDCARD)) {
+ return false;
+ } else {
+ WildcardType t2 = (WildcardType)s;
+ return (t.kind == t2.kind || (t.isExtendsBound() && s.isExtendsBound())) &&
+ isSameType(t.type, t2.type, true);
+ }
+ }
+
+ @Override
+ public Boolean visitClassType(ClassType t, Type s) {
+ if (t == s)
+ return true;
+
+ if (s.isPartial())
+ return visit(s, t);
+
+ if (s.isSuperBound() && !s.isExtendsBound())
+ return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s));
+
+ if (t.isCompound() && s.isCompound()) {
+ if (!visit(supertype(t), supertype(s)))
+ return false;
+
+ Map<Symbol,Type> tMap = new HashMap<>();
+ for (Type ti : interfaces(t)) {
+ if (tMap.containsKey(ti)) {
+ throw new AssertionError("Malformed intersection");
+ }
+ tMap.put(ti.tsym, ti);
+ }
+ for (Type si : interfaces(s)) {
+ if (!tMap.containsKey(si.tsym))
+ return false;
+ Type ti = tMap.remove(si.tsym);
+ if (!visit(ti, si))
+ return false;
+ }
+ return tMap.isEmpty();
+ }
+ return t.tsym == s.tsym
+ && visit(t.getEnclosingType(), s.getEnclosingType())
+ && containsTypes(t.getTypeArguments(), s.getTypeArguments());
+ }
+
+ abstract protected boolean containsTypes(List<Type> ts1, List<Type> ts2);
+
+ @Override
+ public Boolean visitArrayType(ArrayType t, Type s) {
+ if (t == s)
+ return true;
+
+ if (s.isPartial())
+ return visit(s, t);
+
+ return s.hasTag(ARRAY)
+ && containsTypeEquivalent(t.elemtype, elemtype(s));
+ }
+
+ @Override
+ public Boolean visitMethodType(MethodType t, Type s) {
+ // isSameType for methods does not take thrown
+ // exceptions into account!
+ return hasSameArgs(t, s) && visit(t.getReturnType(), s.getReturnType());
+ }
+
+ @Override
+ public Boolean visitPackageType(PackageType t, Type s) {
+ return t == s;
+ }
+
+ @Override
+ public Boolean visitForAll(ForAll t, Type s) {
+ if (!s.hasTag(FORALL)) {
+ return false;
+ }
+
+ ForAll forAll = (ForAll)s;
+ return hasSameBounds(t, forAll)
+ && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
+ }
+
+ @Override
+ public Boolean visitUndetVar(UndetVar t, Type s) {
+ if (s.hasTag(WILDCARD)) {
+ // FIXME, this might be leftovers from before capture conversion
+ return false;
+ }
+
+ if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
+ return true;
+ }
+
+ t.addBound(InferenceBound.EQ, s, Types.this);
+
+ return true;
+ }
+
+ @Override
+ public Boolean visitErrorType(ErrorType t, Type s) {
+ return true;
+ }
+ }
+
+ /**
+ * Standard type-equality relation - type variables are considered
+ * equals if they share the same type symbol.
+ */
+ TypeRelation isSameTypeLoose = new LooseSameTypeVisitor();
+
+ private class LooseSameTypeVisitor extends SameTypeVisitor {
+
+ /** cache of the type-variable pairs being (recursively) tested. */
+ private Set<TypePair> cache = new HashSet<>();
+
+ @Override
+ boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
+ return tv1.tsym == tv2.tsym && checkSameBounds(tv1, tv2);
+ }
+ @Override
+ protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
+ return containsTypeEquivalent(ts1, ts2);
+ }
+
+ /**
+ * Since type-variable bounds can be recursive, we need to protect against
+ * infinite loops - where the same bounds are checked over and over recursively.
+ */
+ private boolean checkSameBounds(TypeVar tv1, TypeVar tv2) {
+ TypePair p = new TypePair(tv1, tv2, true);
+ if (cache.add(p)) {
+ try {
+ return visit(tv1.getUpperBound(), tv2.getUpperBound());
+ } finally {
+ cache.remove(p);
+ }
+ } else {
+ return false;
+ }
+ }
+ };
+
+ /**
+ * Strict type-equality relation - type variables are considered
+ * equals if they share the same object identity.
+ */
+ TypeRelation isSameTypeStrict = new SameTypeVisitor() {
+ @Override
+ boolean sameTypeVars(TypeVar tv1, TypeVar tv2) {
+ return tv1 == tv2;
+ }
+ @Override
+ protected boolean containsTypes(List<Type> ts1, List<Type> ts2) {
+ return isSameTypes(ts1, ts2, true);
+ }
+
+ @Override
+ public Boolean visitWildcardType(WildcardType t, Type s) {
+ if (!s.hasTag(WILDCARD)) {
+ return false;
+ } else {
+ WildcardType t2 = (WildcardType)s;
+ return t.kind == t2.kind &&
+ isSameType(t.type, t2.type, true);
+ }
+ }
+ };
+
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="Contains Type">
+ public boolean containedBy(Type t, Type s) {
+ switch (t.getTag()) {
+ case UNDETVAR:
+ if (s.hasTag(WILDCARD)) {
+ UndetVar undetvar = (UndetVar)t;
+ WildcardType wt = (WildcardType)s;
+ switch(wt.kind) {
+ case UNBOUND:
+ break;
+ case EXTENDS: {
+ Type bound = wildUpperBound(s);
+ undetvar.addBound(InferenceBound.UPPER, bound, this);
+ break;
+ }
+ case SUPER: {
+ Type bound = wildLowerBound(s);
+ undetvar.addBound(InferenceBound.LOWER, bound, this);
+ break;
+ }
+ }
+ return true;
+ } else {
+ return isSameType(t, s);
+ }
+ case ERROR:
+ return true;
+ default:
+ return containsType(s, t);
+ }
+ }
+
+ boolean containsType(List<Type> ts, List<Type> ss) {
+ while (ts.nonEmpty() && ss.nonEmpty()
+ && containsType(ts.head, ss.head)) {
+ ts = ts.tail;
+ ss = ss.tail;
+ }
+ return ts.isEmpty() && ss.isEmpty();
+ }
+
+ /**
+ * Check if t contains s.
+ *
+ * <p>T contains S if:
+ *
+ * <p>{@code L(T) <: L(S) && U(S) <: U(T)}
+ *
+ * <p>This relation is only used by ClassType.isSubtype(), that
+ * is,
+ *
+ * <p>{@code C<S> <: C<T> if T contains S.}
+ *
+ * <p>Because of F-bounds, this relation can lead to infinite
+ * recursion. Thus we must somehow break that recursion. Notice
+ * that containsType() is only called from ClassType.isSubtype().
+ * Since the arguments have already been checked against their
+ * bounds, we know:
+ *
+ * <p>{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
+ *
+ * <p>{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
+ *
+ * @param t a type
+ * @param s a type
+ */
+ public boolean containsType(Type t, Type s) {
+ return containsType.visit(t, s);
+ }
+ // where
+ private TypeRelation containsType = new TypeRelation() {
+
+ public Boolean visitType(Type t, Type s) {
+ if (s.isPartial())
+ return containedBy(s, t);
+ else
+ return isSameType(t, s);
+ }
+
+// void debugContainsType(WildcardType t, Type s) {
+// System.err.println();
+// System.err.format(" does %s contain %s?%n", t, s);
+// System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
+// wildUpperBound(s), s, t, wildUpperBound(t),
+// t.isSuperBound()
+// || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t)));
+// System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
+// wildLowerBound(t), t, s, wildLowerBound(s),
+// t.isExtendsBound()
+// || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s)));
+// System.err.println();
+// }
+
+ @Override
+ public Boolean visitWildcardType(WildcardType t, Type s) {
+ if (s.isPartial())
+ return containedBy(s, t);
+ else {
+// debugContainsType(t, s);
+ return isSameWildcard(t, s)
+ || isCaptureOf(s, t)
+ || ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))) &&
+ (t.isSuperBound() || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))));
+ }
+ }
+
+ @Override
+ public Boolean visitUndetVar(UndetVar t, Type s) {
+ if (!s.hasTag(WILDCARD)) {
+ return isSameType(t, s);
+ } else {
+ return false;
+ }
+ }
+
+ @Override
+ public Boolean visitErrorType(ErrorType t, Type s) {
+ return true;
+ }
+ };
+
+ public boolean isCaptureOf(Type s, WildcardType t) {
+ if (!s.hasTag(TYPEVAR) || !((TypeVar)s).isCaptured())
+ return false;
+ return isSameWildcard(t, ((CapturedType)s).wildcard);
+ }
+
+ public boolean isSameWildcard(WildcardType t, Type s) {
+ if (!s.hasTag(WILDCARD))
+ return false;
+ WildcardType w = (WildcardType)s;
+ return w.kind == t.kind && w.type == t.type;
+ }
+
+ public boolean containsTypeEquivalent(List<Type> ts, List<Type> ss) {
+ while (ts.nonEmpty() && ss.nonEmpty()
+ && containsTypeEquivalent(ts.head, ss.head)) {
+ ts = ts.tail;
+ ss = ss.tail;
+ }
+ return ts.isEmpty() && ss.isEmpty();
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="isCastable">
+ public boolean isCastable(Type t, Type s) {
+ return isCastable(t, s, noWarnings);
+ }
+
+ /**
+ * Is t is castable to s?<br>
+ * s is assumed to be an erased type.<br>
+ * (not defined for Method and ForAll types).
+ */
+ public boolean isCastable(Type t, Type s, Warner warn) {
+ if (t == s)
+ return true;
+ if (t.isPrimitive() != s.isPrimitive()) {
+ t = skipTypeVars(t, false);
+ return (isConvertible(t, s, warn)
+ || (allowObjectToPrimitiveCast &&
+ s.isPrimitive() &&
+ isSubtype(boxedClass(s).type, t)));
+ }
+ if (warn != warnStack.head) {
+ try {
+ warnStack = warnStack.prepend(warn);
+ checkUnsafeVarargsConversion(t, s, warn);
+ return isCastable.visit(t,s);
+ } finally {
+ warnStack = warnStack.tail;
+ }
+ } else {
+ return isCastable.visit(t,s);
+ }
+ }
+ // where
+ private TypeRelation isCastable = new TypeRelation() {
+
+ public Boolean visitType(Type t, Type s) {
+ if (s.hasTag(ERROR))
+ return true;
+
+ switch (t.getTag()) {
+ case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
+ case DOUBLE:
+ return s.isNumeric();
+ case BOOLEAN:
+ return s.hasTag(BOOLEAN);
+ case VOID:
+ return false;
+ case BOT:
+ return isSubtype(t, s);
+ default:
+ throw new AssertionError();
+ }
+ }
+
+ @Override
+ public Boolean visitWildcardType(WildcardType t, Type s) {
+ return isCastable(wildUpperBound(t), s, warnStack.head);
+ }
+
+ @Override
+ public Boolean visitClassType(ClassType t, Type s) {
+ if (s.hasTag(ERROR) || s.hasTag(BOT))
+ return true;
+
+ if (s.hasTag(TYPEVAR)) {
+ if (isCastable(t, s.getUpperBound(), noWarnings)) {
+ warnStack.head.warn(LintCategory.UNCHECKED);
+ return true;
+ } else {
+ return false;
+ }
+ }
+
+ if (t.isCompound() || s.isCompound()) {
+ return !t.isCompound() ?
+ visitCompoundType((ClassType)s, t, true) :
+ visitCompoundType(t, s, false);
+ }
+
+ if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
+ boolean upcast;
+ if ((upcast = isSubtype(erasure(t), erasure(s)))
+ || isSubtype(erasure(s), erasure(t))) {
+ if (!upcast && s.hasTag(ARRAY)) {
+ if (!isReifiable(s))
+ warnStack.head.warn(LintCategory.UNCHECKED);
+ return true;
+ } else if (s.isRaw()) {
+ return true;
+ } else if (t.isRaw()) {
+ if (!isUnbounded(s))
+ warnStack.head.warn(LintCategory.UNCHECKED);
+ return true;
+ }
+ // Assume |a| <: |b|
+ final Type a = upcast ? t : s;
+ final Type b = upcast ? s : t;
+ final boolean HIGH = true;
+ final boolean LOW = false;
+ final boolean DONT_REWRITE_TYPEVARS = false;
+ Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
+ Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
+ Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
+ Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
+ Type lowSub = asSub(bLow, aLow.tsym);
+ Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
+ if (highSub == null) {
+ final boolean REWRITE_TYPEVARS = true;
+ aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
+ aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
+ bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
+ bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
+ lowSub = asSub(bLow, aLow.tsym);
+ highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
+ }
+ if (highSub != null) {
+ if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
+ Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
+ }
+ if (!disjointTypes(aHigh.allparams(), highSub.allparams())
+ && !disjointTypes(aHigh.allparams(), lowSub.allparams())
+ && !disjointTypes(aLow.allparams(), highSub.allparams())
+ && !disjointTypes(aLow.allparams(), lowSub.allparams())) {
+ if (upcast ? giveWarning(a, b) :
+ giveWarning(b, a))
+ warnStack.head.warn(LintCategory.UNCHECKED);
+ return true;
+ }
+ }
+ if (isReifiable(s))
+ return isSubtypeUnchecked(a, b);
+ else
+ return isSubtypeUnchecked(a, b, warnStack.head);
+ }
+
+ // Sidecast
+ if (s.hasTag(CLASS)) {
+ if ((s.tsym.flags() & INTERFACE) != 0) {
+ return ((t.tsym.flags() & FINAL) == 0)
+ ? sideCast(t, s, warnStack.head)
+ : sideCastFinal(t, s, warnStack.head);
+ } else if ((t.tsym.flags() & INTERFACE) != 0) {
+ return ((s.tsym.flags() & FINAL) == 0)
+ ? sideCast(t, s, warnStack.head)
+ : sideCastFinal(t, s, warnStack.head);
+ } else {
+ // unrelated class types
+ return false;
+ }
+ }
+ }
+ return false;
+ }
+
+ boolean visitCompoundType(ClassType ct, Type s, boolean reverse) {
+ Warner warn = noWarnings;
+ for (Type c : directSupertypes(ct)) {
+ warn.clear();
+ if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
+ return false;
+ }
+ if (warn.hasLint(LintCategory.UNCHECKED))
+ warnStack.head.warn(LintCategory.UNCHECKED);
+ return true;
+ }
+
+ @Override
+ public Boolean visitArrayType(ArrayType t, Type s) {
+ switch (s.getTag()) {
+ case ERROR:
+ case BOT:
+ return true;
+ case TYPEVAR:
+ if (isCastable(s, t, noWarnings)) {
+ warnStack.head.warn(LintCategory.UNCHECKED);
+ return true;
+ } else {
+ return false;
+ }
+ case CLASS:
+ return isSubtype(t, s);
+ case ARRAY:
+ if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
+ return elemtype(t).hasTag(elemtype(s).getTag());
+ } else {
+ return visit(elemtype(t), elemtype(s));
+ }
+ default:
+ return false;
+ }
+ }
+
+ @Override
+ public Boolean visitTypeVar(TypeVar t, Type s) {
+ switch (s.getTag()) {
+ case ERROR:
+ case BOT:
+ return true;
+ case TYPEVAR:
+ if (isSubtype(t, s)) {
+ return true;
+ } else if (isCastable(t.bound, s, noWarnings)) {
+ warnStack.head.warn(LintCategory.UNCHECKED);
+ return true;
+ } else {
+ return false;
+ }
+ default:
+ return isCastable(t.bound, s, warnStack.head);
+ }
+ }
+
+ @Override
+ public Boolean visitErrorType(ErrorType t, Type s) {
+ return true;
+ }
+ };
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="disjointTypes">
+ public boolean disjointTypes(List<Type> ts, List<Type> ss) {
+ while (ts.tail != null && ss.tail != null) {
+ if (disjointType(ts.head, ss.head)) return true;
+ ts = ts.tail;
+ ss = ss.tail;
+ }
+ return false;
+ }
+
+ /**
+ * Two types or wildcards are considered disjoint if it can be
+ * proven that no type can be contained in both. It is
+ * conservative in that it is allowed to say that two types are
+ * not disjoint, even though they actually are.
+ *
+ * The type {@code C<X>} is castable to {@code C<Y>} exactly if
+ * {@code X} and {@code Y} are not disjoint.
+ */
+ public boolean disjointType(Type t, Type s) {
+ return disjointType.visit(t, s);
+ }
+ // where
+ private TypeRelation disjointType = new TypeRelation() {
+
+ private Set<TypePair> cache = new HashSet<>();
+
+ @Override
+ public Boolean visitType(Type t, Type s) {
+ if (s.hasTag(WILDCARD))
+ return visit(s, t);
+ else
+ return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
+ }
+
+ private boolean isCastableRecursive(Type t, Type s) {
+ TypePair pair = new TypePair(t, s);
+ if (cache.add(pair)) {
+ try {
+ return Types.this.isCastable(t, s);
+ } finally {
+ cache.remove(pair);
+ }
+ } else {
+ return true;
+ }
+ }
+
+ private boolean notSoftSubtypeRecursive(Type t, Type s) {
+ TypePair pair = new TypePair(t, s);
+ if (cache.add(pair)) {
+ try {
+ return Types.this.notSoftSubtype(t, s);
+ } finally {
+ cache.remove(pair);
+ }
+ } else {
+ return false;
+ }
+ }
+
+ @Override
+ public Boolean visitWildcardType(WildcardType t, Type s) {
+ if (t.isUnbound())
+ return false;
+
+ if (!s.hasTag(WILDCARD)) {
+ if (t.isExtendsBound())
+ return notSoftSubtypeRecursive(s, t.type);
+ else
+ return notSoftSubtypeRecursive(t.type, s);
+ }
+
+ if (s.isUnbound())
+ return false;
+
+ if (t.isExtendsBound()) {
+ if (s.isExtendsBound())
+ return !isCastableRecursive(t.type, wildUpperBound(s));
+ else if (s.isSuperBound())
+ return notSoftSubtypeRecursive(wildLowerBound(s), t.type);
+ } else if (t.isSuperBound()) {
+ if (s.isExtendsBound())
+ return notSoftSubtypeRecursive(t.type, wildUpperBound(s));
+ }
+ return false;
+ }
+ };
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="cvarLowerBounds">
+ public List<Type> cvarLowerBounds(List<Type> ts) {
+ return ts.map(cvarLowerBoundMapping);
+ }
+ private final TypeMapping<Void> cvarLowerBoundMapping = new TypeMapping<Void>() {
+ @Override
+ public Type visitCapturedType(CapturedType t, Void _unused) {
+ return cvarLowerBound(t);
+ }
+ };
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="notSoftSubtype">
+ /**
+ * This relation answers the question: is impossible that
+ * something of type `t' can be a subtype of `s'? This is
+ * different from the question "is `t' not a subtype of `s'?"
+ * when type variables are involved: Integer is not a subtype of T
+ * where {@code <T extends Number>} but it is not true that Integer cannot
+ * possibly be a subtype of T.
+ */
+ public boolean notSoftSubtype(Type t, Type s) {
+ if (t == s) return false;
+ if (t.hasTag(TYPEVAR)) {
+ TypeVar tv = (TypeVar) t;
+ return !isCastable(tv.bound,
+ relaxBound(s),
+ noWarnings);
+ }
+ if (!s.hasTag(WILDCARD))
+ s = cvarUpperBound(s);
+
+ return !isSubtype(t, relaxBound(s));
+ }
+
+ private Type relaxBound(Type t) {
+ return (t.hasTag(TYPEVAR)) ?
+ rewriteQuantifiers(skipTypeVars(t, false), true, true) :
+ t;
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="isReifiable">
+ public boolean isReifiable(Type t) {
+ return isReifiable.visit(t);
+ }
+ // where
+ private UnaryVisitor<Boolean> isReifiable = new UnaryVisitor<Boolean>() {
+
+ public Boolean visitType(Type t, Void ignored) {
+ return true;
+ }
+
+ @Override
+ public Boolean visitClassType(ClassType t, Void ignored) {
+ if (t.isCompound())
+ return false;
+ else {
+ if (!t.isParameterized())
+ return true;
+
+ for (Type param : t.allparams()) {
+ if (!param.isUnbound())
+ return false;
+ }
+ return true;
+ }
+ }
+
+ @Override
+ public Boolean visitArrayType(ArrayType t, Void ignored) {
+ return visit(t.elemtype);
+ }
+
+ @Override
+ public Boolean visitTypeVar(TypeVar t, Void ignored) {
+ return false;
+ }
+ };
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="Array Utils">
+ public boolean isArray(Type t) {
+ while (t.hasTag(WILDCARD))
+ t = wildUpperBound(t);
+ return t.hasTag(ARRAY);
+ }
+
+ /**
+ * The element type of an array.
+ */
+ public Type elemtype(Type t) {
+ switch (t.getTag()) {
+ case WILDCARD:
+ return elemtype(wildUpperBound(t));
+ case ARRAY:
+ return ((ArrayType)t).elemtype;
+ case FORALL:
+ return elemtype(((ForAll)t).qtype);
+ case ERROR:
+ return t;
+ default:
+ return null;
+ }
+ }
+
+ public Type elemtypeOrType(Type t) {
+ Type elemtype = elemtype(t);
+ return elemtype != null ?
+ elemtype :
+ t;
+ }
+
+ /**
+ * Mapping to take element type of an arraytype
+ */
+ private TypeMapping<Void> elemTypeFun = new TypeMapping<Void>() {
+ @Override
+ public Type visitArrayType(ArrayType t, Void _unused) {
+ return t.elemtype;
+ }
+
+ @Override
+ public Type visitTypeVar(TypeVar t, Void _unused) {
+ return visit(skipTypeVars(t, false));
+ }
+ };
+
+ /**
+ * The number of dimensions of an array type.
+ */
+ public int dimensions(Type t) {
+ int result = 0;
+ while (t.hasTag(ARRAY)) {
+ result++;
+ t = elemtype(t);
+ }
+ return result;
+ }
+
+ /**
+ * Returns an ArrayType with the component type t
+ *
+ * @param t The component type of the ArrayType
+ * @return the ArrayType for the given component
+ */
+ public ArrayType makeArrayType(Type t) {
+ if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
+ Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
+ }
+ return new ArrayType(t, syms.arrayClass);
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="asSuper">
+ /**
+ * Return the (most specific) base type of t that starts with the
+ * given symbol. If none exists, return null.
+ *
+ * Caveat Emptor: Since javac represents the class of all arrays with a singleton
+ * symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant,
+ * this method could yield surprising answers when invoked on arrays. For example when
+ * invoked with t being byte [] and sym being t.sym itself, asSuper would answer null.
+ *
+ * @param t a type
+ * @param sym a symbol
+ */
+ public Type asSuper(Type t, Symbol sym) {
+ /* Some examples:
+ *
+ * (Enum<E>, Comparable) => Comparable<E>
+ * (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum<c.s.s.d.AttributeTree.ValueKind>
+ * (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree
+ * (j.u.List<capture#160 of ? extends c.s.s.d.DocTree>, Iterable) =>
+ * Iterable<capture#160 of ? extends c.s.s.d.DocTree>
+ */
+ if (sym.type == syms.objectType) { //optimization
+ return syms.objectType;
+ }
+ return asSuper.visit(t, sym);
+ }
+ // where
+ private SimpleVisitor<Type,Symbol> asSuper = new SimpleVisitor<Type,Symbol>() {
+
+ public Type visitType(Type t, Symbol sym) {
+ return null;
+ }
+
+ @Override
+ public Type visitClassType(ClassType t, Symbol sym) {
+ if (t.tsym == sym)
+ return t;
+
+ Type st = supertype(t);
+ if (st.hasTag(CLASS) || st.hasTag(TYPEVAR)) {
+ Type x = asSuper(st, sym);
+ if (x != null)
+ return x;
+ }
+ if ((sym.flags() & INTERFACE) != 0) {
+ for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
+ if (!l.head.hasTag(ERROR)) {
+ Type x = asSuper(l.head, sym);
+ if (x != null)
+ return x;
+ }
+ }
+ }
+ return null;
+ }
+
+ @Override
+ public Type visitArrayType(ArrayType t, Symbol sym) {
+ return isSubtype(t, sym.type) ? sym.type : null;
+ }
+
+ @Override
+ public Type visitTypeVar(TypeVar t, Symbol sym) {
+ if (t.tsym == sym)
+ return t;
+ else
+ return asSuper(t.bound, sym);
+ }
+
+ @Override
+ public Type visitErrorType(ErrorType t, Symbol sym) {
+ return t;
+ }
+ };
+
+ /**
+ * Return the base type of t or any of its outer types that starts
+ * with the given symbol. If none exists, return null.
+ *
+ * @param t a type
+ * @param sym a symbol
+ */
+ public Type asOuterSuper(Type t, Symbol sym) {
+ switch (t.getTag()) {
+ case CLASS:
+ do {
+ Type s = asSuper(t, sym);
+ if (s != null) return s;
+ t = t.getEnclosingType();
+ } while (t.hasTag(CLASS));
+ return null;
+ case ARRAY:
+ return isSubtype(t, sym.type) ? sym.type : null;
+ case TYPEVAR:
+ return asSuper(t, sym);
+ case ERROR:
+ return t;
+ default:
+ return null;
+ }
+ }
+
+ /**
+ * Return the base type of t or any of its enclosing types that
+ * starts with the given symbol. If none exists, return null.
+ *
+ * @param t a type
+ * @param sym a symbol
+ */
+ public Type asEnclosingSuper(Type t, Symbol sym) {
+ switch (t.getTag()) {
+ case CLASS:
+ do {
+ Type s = asSuper(t, sym);
+ if (s != null) return s;
+ Type outer = t.getEnclosingType();
+ t = (outer.hasTag(CLASS)) ? outer :
+ (t.tsym.owner.enclClass() != null) ? t.tsym.owner.enclClass().type :
+ Type.noType;
+ } while (t.hasTag(CLASS));
+ return null;
+ case ARRAY:
+ return isSubtype(t, sym.type) ? sym.type : null;
+ case TYPEVAR:
+ return asSuper(t, sym);
+ case ERROR:
+ return t;
+ default:
+ return null;
+ }
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="memberType">
+ /**
+ * The type of given symbol, seen as a member of t.
+ *
+ * @param t a type
+ * @param sym a symbol
+ */
+ public Type memberType(Type t, Symbol sym) {
+ return (sym.flags() & STATIC) != 0
+ ? sym.type
+ : memberType.visit(t, sym);
+ }
+ // where
+ private SimpleVisitor<Type,Symbol> memberType = new SimpleVisitor<Type,Symbol>() {
+
+ public Type visitType(Type t, Symbol sym) {
+ return sym.type;
+ }
+
+ @Override
+ public Type visitWildcardType(WildcardType t, Symbol sym) {
+ return memberType(wildUpperBound(t), sym);
+ }
+
+ @Override
+ public Type visitClassType(ClassType t, Symbol sym) {
+ Symbol owner = sym.owner;
+ long flags = sym.flags();
+ if (((flags & STATIC) == 0) && owner.type.isParameterized()) {
+ Type base = asOuterSuper(t, owner);
+ //if t is an intersection type T = CT & I1 & I2 ... & In
+ //its supertypes CT, I1, ... In might contain wildcards
+ //so we need to go through capture conversion
+ base = t.isCompound() ? capture(base) : base;
+ if (base != null) {
+ List<Type> ownerParams = owner.type.allparams();
+ List<Type> baseParams = base.allparams();
+ if (ownerParams.nonEmpty()) {
+ if (baseParams.isEmpty()) {
+ // then base is a raw type
+ return erasure(sym.type);
+ } else {
+ return subst(sym.type, ownerParams, baseParams);
+ }
+ }
+ }
+ }
+ return sym.type;
+ }
+
+ @Override
+ public Type visitTypeVar(TypeVar t, Symbol sym) {
+ return memberType(t.bound, sym);
+ }
+
+ @Override
+ public Type visitErrorType(ErrorType t, Symbol sym) {
+ return t;
+ }
+ };
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="isAssignable">
+ public boolean isAssignable(Type t, Type s) {
+ return isAssignable(t, s, noWarnings);
+ }
+
+ /**
+ * Is t assignable to s?<br>
+ * Equivalent to subtype except for constant values and raw
+ * types.<br>
+ * (not defined for Method and ForAll types)
+ */
+ public boolean isAssignable(Type t, Type s, Warner warn) {
+ if (t.hasTag(ERROR))
+ return true;
+ if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
+ int value = ((Number)t.constValue()).intValue();
+ switch (s.getTag()) {
+ case BYTE:
+ case CHAR:
+ case SHORT:
+ case INT:
+ if (s.getTag().checkRange(value))
+ return true;
+ break;
+ case CLASS:
+ switch (unboxedType(s).getTag()) {
+ case BYTE:
+ case CHAR:
+ case SHORT:
+ return isAssignable(t, unboxedType(s), warn);
+ }
+ break;
+ }
+ }
+ return isConvertible(t, s, warn);
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="erasure">
+ /**
+ * The erasure of t {@code |t|} -- the type that results when all
+ * type parameters in t are deleted.
+ */
+ public Type erasure(Type t) {
+ return eraseNotNeeded(t) ? t : erasure(t, false);
+ }
+ //where
+ private boolean eraseNotNeeded(Type t) {
+ // We don't want to erase primitive types and String type as that
+ // operation is idempotent. Also, erasing these could result in loss
+ // of information such as constant values attached to such types.
+ return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
+ }
+
+ private Type erasure(Type t, boolean recurse) {
+ if (t.isPrimitive()) {
+ return t; /* fast special case */
+ } else {
+ Type out = erasure.visit(t, recurse);
+ return out;
+ }
+ }
+ // where
+ private TypeMapping<Boolean> erasure = new StructuralTypeMapping<Boolean>() {
+ private Type combineMetadata(final Type s,
+ final Type t) {
+ if (t.getMetadata() != TypeMetadata.EMPTY) {
+ switch (s.getKind()) {
+ case OTHER:
+ case UNION:
+ case INTERSECTION:
+ case PACKAGE:
+ case EXECUTABLE:
+ case NONE:
+ case VOID:
+ case ERROR:
+ return s;
+ default: return s.cloneWithMetadata(s.getMetadata().without(Kind.ANNOTATIONS));
+ }
+ } else {
+ return s;
+ }
+ }
+
+ public Type visitType(Type t, Boolean recurse) {
+ if (t.isPrimitive())
+ return t; /*fast special case*/
+ else {
+ //other cases already handled
+ return combineMetadata(t, t);
+ }
+ }
+
+ @Override
+ public Type visitWildcardType(WildcardType t, Boolean recurse) {
+ Type erased = erasure(wildUpperBound(t), recurse);
+ return combineMetadata(erased, t);
+ }
+
+ @Override
+ public Type visitClassType(ClassType t, Boolean recurse) {
+ Type erased = t.tsym.erasure(Types.this);
+ if (recurse) {
+ erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym,
+ t.getMetadata().without(Kind.ANNOTATIONS));
+ return erased;
+ } else {
+ return combineMetadata(erased, t);
+ }
+ }
+
+ @Override
+ public Type visitTypeVar(TypeVar t, Boolean recurse) {
+ Type erased = erasure(t.bound, recurse);
+ return combineMetadata(erased, t);
+ }
+ };
+
+ public List<Type> erasure(List<Type> ts) {
+ return erasure.visit(ts, false);
+ }
+
+ public Type erasureRecursive(Type t) {
+ return erasure(t, true);
+ }
+
+ public List<Type> erasureRecursive(List<Type> ts) {
+ return erasure.visit(ts, true);
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="makeIntersectionType">
+ /**
+ * Make an intersection type from non-empty list of types. The list should be ordered according to
+ * {@link TypeSymbol#precedes(TypeSymbol, Types)}. Note that this might cause a symbol completion.
+ * Hence, this version of makeIntersectionType may not be called during a classfile read.
+ *
+ * @param bounds the types from which the intersection type is formed
+ */
+ public IntersectionClassType makeIntersectionType(List<Type> bounds) {
+ return makeIntersectionType(bounds, bounds.head.tsym.isInterface());
+ }
+
+ /**
+ * Make an intersection type from non-empty list of types. The list should be ordered according to
+ * {@link TypeSymbol#precedes(TypeSymbol, Types)}. This does not cause symbol completion as
+ * an extra parameter indicates as to whether all bounds are interfaces - in which case the
+ * supertype is implicitly assumed to be 'Object'.
+ *
+ * @param bounds the types from which the intersection type is formed
+ * @param allInterfaces are all bounds interface types?
+ */
+ public IntersectionClassType makeIntersectionType(List<Type> bounds, boolean allInterfaces) {
+ Assert.check(bounds.nonEmpty());
+ Type firstExplicitBound = bounds.head;
+ if (allInterfaces) {
+ bounds = bounds.prepend(syms.objectType);
+ }
+ ClassSymbol bc =
+ new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
+ Type.moreInfo
+ ? names.fromString(bounds.toString())
+ : names.empty,
+ null,
+ syms.noSymbol);
+ IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
+ bc.type = intersectionType;
+ bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
+ syms.objectType : // error condition, recover
+ erasure(firstExplicitBound);
+ bc.members_field = WriteableScope.create(bc);
+ return intersectionType;
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="supertype">
+ public Type supertype(Type t) {
+ return supertype.visit(t);
+ }
+ // where
+ private UnaryVisitor<Type> supertype = new UnaryVisitor<Type>() {
+
+ public Type visitType(Type t, Void ignored) {
+ // A note on wildcards: there is no good way to
+ // determine a supertype for a super bounded wildcard.
+ return Type.noType;
+ }
+
+ @Override
+ public Type visitClassType(ClassType t, Void ignored) {
+ if (t.supertype_field == null) {
+ Type supertype = ((ClassSymbol)t.tsym).getSuperclass();
+ // An interface has no superclass; its supertype is Object.
+ if (t.isInterface())
+ supertype = ((ClassType)t.tsym.type).supertype_field;
+ if (t.supertype_field == null) {
+ List<Type> actuals = classBound(t).allparams();
+ List<Type> formals = t.tsym.type.allparams();
+ if (t.hasErasedSupertypes()) {
+ t.supertype_field = erasureRecursive(supertype);
+ } else if (formals.nonEmpty()) {
+ t.supertype_field = subst(supertype, formals, actuals);
+ }
+ else {
+ t.supertype_field = supertype;
+ }
+ }
+ }
+ return t.supertype_field;
+ }
+
+ /**
+ * The supertype is always a class type. If the type
+ * variable's bounds start with a class type, this is also
+ * the supertype. Otherwise, the supertype is
+ * java.lang.Object.
+ */
+ @Override
+ public Type visitTypeVar(TypeVar t, Void ignored) {
+ if (t.bound.hasTag(TYPEVAR) ||
+ (!t.bound.isCompound() && !t.bound.isInterface())) {
+ return t.bound;
+ } else {
+ return supertype(t.bound);
+ }
+ }
+
+ @Override
+ public Type visitArrayType(ArrayType t, Void ignored) {
+ if (t.elemtype.isPrimitive() || isSameType(t.elemtype, syms.objectType))
+ return arraySuperType();
+ else
+ return new ArrayType(supertype(t.elemtype), t.tsym);
+ }
+
+ @Override
+ public Type visitErrorType(ErrorType t, Void ignored) {
+ return Type.noType;
+ }
+ };
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="interfaces">
+ /**
+ * Return the interfaces implemented by this class.
+ */
+ public List<Type> interfaces(Type t) {
+ return interfaces.visit(t);
+ }
+ // where
+ private UnaryVisitor<List<Type>> interfaces = new UnaryVisitor<List<Type>>() {
+
+ public List<Type> visitType(Type t, Void ignored) {
+ return List.nil();
+ }
+
+ @Override
+ public List<Type> visitClassType(ClassType t, Void ignored) {
+ if (t.interfaces_field == null) {
+ List<Type> interfaces = ((ClassSymbol)t.tsym).getInterfaces();
+ if (t.interfaces_field == null) {
+ // If t.interfaces_field is null, then t must
+ // be a parameterized type (not to be confused
+ // with a generic type declaration).
+ // Terminology:
+ // Parameterized type: List<String>
+ // Generic type declaration: class List<E> { ... }
+ // So t corresponds to List<String> and
+ // t.tsym.type corresponds to List<E>.
+ // The reason t must be parameterized type is
+ // that completion will happen as a side
+ // effect of calling
+ // ClassSymbol.getInterfaces. Since
+ // t.interfaces_field is null after
+ // completion, we can assume that t is not the
+ // type of a class/interface declaration.
+ Assert.check(t != t.tsym.type, t);
+ List<Type> actuals = t.allparams();
+ List<Type> formals = t.tsym.type.allparams();
+ if (t.hasErasedSupertypes()) {
+ t.interfaces_field = erasureRecursive(interfaces);
+ } else if (formals.nonEmpty()) {
+ t.interfaces_field = subst(interfaces, formals, actuals);
+ }
+ else {
+ t.interfaces_field = interfaces;
+ }
+ }
+ }
+ return t.interfaces_field;
+ }
+
+ @Override
+ public List<Type> visitTypeVar(TypeVar t, Void ignored) {
+ if (t.bound.isCompound())
+ return interfaces(t.bound);
+
+ if (t.bound.isInterface())
+ return List.of(t.bound);
+
+ return List.nil();
+ }
+ };
+
+ public List<Type> directSupertypes(Type t) {
+ return directSupertypes.visit(t);
+ }
+ // where
+ private final UnaryVisitor<List<Type>> directSupertypes = new UnaryVisitor<List<Type>>() {
+
+ public List<Type> visitType(final Type type, final Void ignored) {
+ if (!type.isIntersection()) {
+ final Type sup = supertype(type);
+ return (sup == Type.noType || sup == type || sup == null)
+ ? interfaces(type)
+ : interfaces(type).prepend(sup);
+ } else {
+ return ((IntersectionClassType)type).getExplicitComponents();
+ }
+ }
+ };
+
+ public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
+ for (Type i2 : interfaces(origin.type)) {
+ if (isym == i2.tsym) return true;
+ }
+ return false;
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="isDerivedRaw">
+ Map<Type,Boolean> isDerivedRawCache = new HashMap<>();
+
+ public boolean isDerivedRaw(Type t) {
+ Boolean result = isDerivedRawCache.get(t);
+ if (result == null) {
+ result = isDerivedRawInternal(t);
+ isDerivedRawCache.put(t, result);
+ }
+ return result;
+ }
+
+ public boolean isDerivedRawInternal(Type t) {
+ if (t.isErroneous())
+ return false;
+ return
+ t.isRaw() ||
+ supertype(t) != Type.noType && isDerivedRaw(supertype(t)) ||
+ isDerivedRaw(interfaces(t));
+ }
+
+ public boolean isDerivedRaw(List<Type> ts) {
+ List<Type> l = ts;
+ while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
+ return l.nonEmpty();
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="setBounds">
+ /**
+ * Same as {@link Types#setBounds(TypeVar, List, boolean)}, except that third parameter is computed directly,
+ * as follows: if all all bounds are interface types, the computed supertype is Object,otherwise
+ * the supertype is simply left null (in this case, the supertype is assumed to be the head of
+ * the bound list passed as second argument). Note that this check might cause a symbol completion.
+ * Hence, this version of setBounds may not be called during a classfile read.
+ *
+ * @param t a type variable
+ * @param bounds the bounds, must be nonempty
+ */
+ public void setBounds(TypeVar t, List<Type> bounds) {
+ setBounds(t, bounds, bounds.head.tsym.isInterface());
+ }
+
+ /**
+ * Set the bounds field of the given type variable to reflect a (possibly multiple) list of bounds.
+ * This does not cause symbol completion as an extra parameter indicates as to whether all bounds
+ * are interfaces - in which case the supertype is implicitly assumed to be 'Object'.
+ *
+ * @param t a type variable
+ * @param bounds the bounds, must be nonempty
+ * @param allInterfaces are all bounds interface types?
+ */
+ public void setBounds(TypeVar t, List<Type> bounds, boolean allInterfaces) {
+ t.bound = bounds.tail.isEmpty() ?
+ bounds.head :
+ makeIntersectionType(bounds, allInterfaces);
+ t.rank_field = -1;
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="getBounds">
+ /**
+ * Return list of bounds of the given type variable.
+ */
+ public List<Type> getBounds(TypeVar t) {
+ if (t.bound.hasTag(NONE))
+ return List.nil();
+ else if (t.bound.isErroneous() || !t.bound.isCompound())
+ return List.of(t.bound);
+ else if ((erasure(t).tsym.flags() & INTERFACE) == 0)
+ return interfaces(t).prepend(supertype(t));
+ else
+ // No superclass was given in bounds.
+ // In this case, supertype is Object, erasure is first interface.
+ return interfaces(t);
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="classBound">
+ /**
+ * If the given type is a (possibly selected) type variable,
+ * return the bounding class of this type, otherwise return the
+ * type itself.
+ */
+ public Type classBound(Type t) {
+ return classBound.visit(t);
+ }
+ // where
+ private UnaryVisitor<Type> classBound = new UnaryVisitor<Type>() {
+
+ public Type visitType(Type t, Void ignored) {
+ return t;
+ }
+
+ @Override
+ public Type visitClassType(ClassType t, Void ignored) {
+ Type outer1 = classBound(t.getEnclosingType());
+ if (outer1 != t.getEnclosingType())
+ return new ClassType(outer1, t.getTypeArguments(), t.tsym,
+ t.getMetadata());
+ else
+ return t;
+ }
+
+ @Override
+ public Type visitTypeVar(TypeVar t, Void ignored) {
+ return classBound(supertype(t));
+ }
+
+ @Override
+ public Type visitErrorType(ErrorType t, Void ignored) {
+ return t;
+ }
+ };
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="sub signature / override equivalence">
+ /**
+ * Returns true iff the first signature is a <em>sub
+ * signature</em> of the other. This is <b>not</b> an equivalence
+ * relation.
+ *
+ * @jls section 8.4.2.
+ * @see #overrideEquivalent(Type t, Type s)
+ * @param t first signature (possibly raw).
+ * @param s second signature (could be subjected to erasure).
+ * @return true if t is a sub signature of s.
+ */
+ public boolean isSubSignature(Type t, Type s) {
+ return isSubSignature(t, s, true);
+ }
+
+ public boolean isSubSignature(Type t, Type s, boolean strict) {
+ return hasSameArgs(t, s, strict) || hasSameArgs(t, erasure(s), strict);
+ }
+
+ /**
+ * Returns true iff these signatures are related by <em>override
+ * equivalence</em>. This is the natural extension of
+ * isSubSignature to an equivalence relation.
+ *
+ * @jls section 8.4.2.
+ * @see #isSubSignature(Type t, Type s)
+ * @param t a signature (possible raw, could be subjected to
+ * erasure).
+ * @param s a signature (possible raw, could be subjected to
+ * erasure).
+ * @return true if either argument is a sub signature of the other.
+ */
+ public boolean overrideEquivalent(Type t, Type s) {
+ return hasSameArgs(t, s) ||
+ hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
+ }
+
+ public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
+ for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
+ if (msym.overrides(sym, origin, Types.this, true)) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ /**
+ * This enum defines the strategy for implementing most specific return type check
+ * during the most specific and functional interface checks.
+ */
+ public enum MostSpecificReturnCheck {
+ /**
+ * Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
+ * method type variables (if either method is generic) and (ii) subtyping should be replaced
+ * by type-equivalence for primitives. This is essentially an inlined version of
+ * {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
+ * replaced with a strict subtyping check.
+ */
+ BASIC() {
+ @Override
+ public boolean test(Type mt1, Type mt2, Types types) {
+ List<Type> tvars = mt1.getTypeArguments();
+ List<Type> svars = mt2.getTypeArguments();
+ Type t = mt1.getReturnType();
+ Type s = types.subst(mt2.getReturnType(), svars, tvars);
+ return types.isSameType(t, s) ||
+ !t.isPrimitive() &&
+ !s.isPrimitive() &&
+ types.isSubtype(t, s);
+ }
+ },
+ /**
+ * Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
+ */
+ RTS() {
+ @Override
+ public boolean test(Type mt1, Type mt2, Types types) {
+ return types.returnTypeSubstitutable(mt1, mt2);
+ }
+ };
+
+ public abstract boolean test(Type mt1, Type mt2, Types types);
+ }
+
+ /**
+ * Merge multiple abstract methods. The preferred method is a method that is a subsignature
+ * of all the other signatures and whose return type is more specific {@see MostSpecificReturnCheck}.
+ * The resulting preferred method has a thrown clause that is the intersection of the merged
+ * methods' clauses.
+ */
+ public Optional<Symbol> mergeAbstracts(List<Symbol> ambiguousInOrder, Type site, boolean sigCheck) {
+ //first check for preconditions
+ boolean shouldErase = false;
+ List<Type> erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
+ for (Symbol s : ambiguousInOrder) {
+ if ((s.flags() & ABSTRACT) == 0 ||
+ (sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
+ return Optional.empty();
+ } else if (s.type.hasTag(FORALL)) {
+ shouldErase = true;
+ }
+ }
+ //then merge abstracts
+ for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
+ outer: for (Symbol s : ambiguousInOrder) {
+ Type mt = memberType(site, s);
+ List<Type> allThrown = mt.getThrownTypes();
+ for (Symbol s2 : ambiguousInOrder) {
+ if (s != s2) {
+ Type mt2 = memberType(site, s2);
+ if (!isSubSignature(mt, mt2) ||
+ !mostSpecificReturnCheck.test(mt, mt2, this)) {
+ //ambiguity cannot be resolved
+ continue outer;
+ } else {
+ List<Type> thrownTypes2 = mt2.getThrownTypes();
+ if (!mt.hasTag(FORALL) && shouldErase) {
+ thrownTypes2 = erasure(thrownTypes2);
+ } else if (mt.hasTag(FORALL)) {
+ //subsignature implies that if most specific is generic, then all other
+ //methods are too
+ Assert.check(mt2.hasTag(FORALL));
+ // if both are generic methods, adjust thrown types ahead of intersection computation
+ thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
+ }
+ allThrown = chk.intersect(allThrown, thrownTypes2);
+ }
+ }
+ }
+ return (allThrown == mt.getThrownTypes()) ?
+ Optional.of(s) :
+ Optional.of(new MethodSymbol(
+ s.flags(),
+ s.name,
+ createMethodTypeWithThrown(s.type, allThrown),
+ s.owner) {
+ @Override
+ public Symbol baseSymbol() {
+ return s;
+ }
+ });
+ }
+ }
+ return Optional.empty();
+ }
+
+ // <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
+ class ImplementationCache {
+
+ private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map = new WeakHashMap<>();
+
+ class Entry {
+ final MethodSymbol cachedImpl;
+ final Filter<Symbol> implFilter;
+ final boolean checkResult;
+ final int prevMark;
+
+ public Entry(MethodSymbol cachedImpl,
+ Filter<Symbol> scopeFilter,
+ boolean checkResult,
+ int prevMark) {
+ this.cachedImpl = cachedImpl;
+ this.implFilter = scopeFilter;
+ this.checkResult = checkResult;
+ this.prevMark = prevMark;
+ }
+
+ boolean matches(Filter<Symbol> scopeFilter, boolean checkResult, int mark) {
+ return this.implFilter == scopeFilter &&
+ this.checkResult == checkResult &&
+ this.prevMark == mark;
+ }
+ }
+
+ MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
+ SoftReference<Map<TypeSymbol, Entry>> ref_cache = _map.get(ms);
+ Map<TypeSymbol, Entry> cache = ref_cache != null ? ref_cache.get() : null;
+ if (cache == null) {
+ cache = new HashMap<>();
+ _map.put(ms, new SoftReference<>(cache));
+ }
+ Entry e = cache.get(origin);
+ CompoundScope members = membersClosure(origin.type, true);
+ if (e == null ||
+ !e.matches(implFilter, checkResult, members.getMark())) {
+ MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
+ cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
+ return impl;
+ }
+ else {
+ return e.cachedImpl;
+ }
+ }
+
+ private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
+ for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
+ t = skipTypeVars(t, false);
+ TypeSymbol c = t.tsym;
+ Symbol bestSoFar = null;
+ for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
+ if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
+ bestSoFar = sym;
+ if ((sym.flags() & ABSTRACT) == 0) {
+ //if concrete impl is found, exit immediately
+ break;
+ }
+ }
+ }
+ if (bestSoFar != null) {
+ //return either the (only) concrete implementation or the first abstract one
+ return (MethodSymbol)bestSoFar;
+ }
+ }
+ return null;
+ }
+ }
+
+ private ImplementationCache implCache = new ImplementationCache();
+
+ public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter<Symbol> implFilter) {
+ return implCache.get(ms, origin, checkResult, implFilter);
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="compute transitive closure of all members in given site">
+ class MembersClosureCache extends SimpleVisitor<Scope.CompoundScope, Void> {
+
+ private Map<TypeSymbol, CompoundScope> _map = new HashMap<>();
+
+ Set<TypeSymbol> seenTypes = new HashSet<>();
+
+ class MembersScope extends CompoundScope {
+
+ CompoundScope scope;
+
+ public MembersScope(CompoundScope scope) {
+ super(scope.owner);
+ this.scope = scope;
+ }
+
+ Filter<Symbol> combine(Filter<Symbol> sf) {
+ return s -> !s.owner.isInterface() && (sf == null || sf.accepts(s));
+ }
+
+ @Override
+ public Iterable<Symbol> getSymbols(Filter<Symbol> sf, LookupKind lookupKind) {
+ return scope.getSymbols(combine(sf), lookupKind);
+ }
+
+ @Override
+ public Iterable<Symbol> getSymbolsByName(Name name, Filter<Symbol> sf, LookupKind lookupKind) {
+ return scope.getSymbolsByName(name, combine(sf), lookupKind);
+ }
+
+ @Override
+ public int getMark() {
+ return scope.getMark();
+ }
+ }
+
+ CompoundScope nilScope;
+
+ /** members closure visitor methods **/
+
+ public CompoundScope visitType(Type t, Void _unused) {
+ if (nilScope == null) {
+ nilScope = new CompoundScope(syms.noSymbol);
+ }
+ return nilScope;
+ }
+
+ @Override
+ public CompoundScope visitClassType(ClassType t, Void _unused) {
+ if (!seenTypes.add(t.tsym)) {
+ //this is possible when an interface is implemented in multiple
+ //superclasses, or when a class hierarchy is circular - in such
+ //cases we don't need to recurse (empty scope is returned)
+ return new CompoundScope(t.tsym);
+ }
+ try {
+ seenTypes.add(t.tsym);
+ ClassSymbol csym = (ClassSymbol)t.tsym;
+ CompoundScope membersClosure = _map.get(csym);
+ if (membersClosure == null) {
+ membersClosure = new CompoundScope(csym);
+ for (Type i : interfaces(t)) {
+ membersClosure.prependSubScope(visit(i, null));
+ }
+ membersClosure.prependSubScope(visit(supertype(t), null));
+ membersClosure.prependSubScope(csym.members());
+ _map.put(csym, membersClosure);
+ }
+ return membersClosure;
+ }
+ finally {
+ seenTypes.remove(t.tsym);
+ }
+ }
+
+ @Override
+ public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
+ return visit(t.getUpperBound(), null);
+ }
+ }
+
+ private MembersClosureCache membersCache = new MembersClosureCache();
+
+ public CompoundScope membersClosure(Type site, boolean skipInterface) {
+ CompoundScope cs = membersCache.visit(site, null);
+ Assert.checkNonNull(cs, () -> "type " + site);
+ return skipInterface ? membersCache.new MembersScope(cs) : cs;
+ }
+ // </editor-fold>
+
+
+ /** Return first abstract member of class `sym'.
+ */
+ public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
+ try {
+ return firstUnimplementedAbstractImpl(sym, sym);
+ } catch (CompletionFailure ex) {
+ chk.completionError(enter.getEnv(sym).tree.pos(), ex);
+ return null;
+ }
+ }
+ //where:
+ private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
+ MethodSymbol undef = null;
+ // Do not bother to search in classes that are not abstract,
+ // since they cannot have abstract members.
+ if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
+ Scope s = c.members();
+ for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
+ if (sym.kind == MTH &&
+ (sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
+ MethodSymbol absmeth = (MethodSymbol)sym;
+ MethodSymbol implmeth = absmeth.implementation(impl, this, true);
+ if (implmeth == null || implmeth == absmeth) {
+ //look for default implementations
+ if (allowDefaultMethods) {
+ MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
+ if (prov != null && prov.overrides(absmeth, impl, this, true)) {
+ implmeth = prov;
+ }
+ }
+ }
+ if (implmeth == null || implmeth == absmeth) {
+ undef = absmeth;
+ break;
+ }
+ }
+ }
+ if (undef == null) {
+ Type st = supertype(c.type);
+ if (st.hasTag(CLASS))
+ undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
+ }
+ for (List<Type> l = interfaces(c.type);
+ undef == null && l.nonEmpty();
+ l = l.tail) {
+ undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
+ }
+ }
+ return undef;
+ }
+
+ public class CandidatesCache {
+ public Map<Entry, List<MethodSymbol>> cache = new WeakHashMap<>();
+
+ class Entry {
+ Type site;
+ MethodSymbol msym;
+
+ Entry(Type site, MethodSymbol msym) {
+ this.site = site;
+ this.msym = msym;
+ }
+
+ @Override
+ public boolean equals(Object obj) {
+ if (obj instanceof Entry) {
+ Entry e = (Entry)obj;
+ return e.msym == msym && isSameType(site, e.site);
+ } else {
+ return false;
+ }
+ }
+
+ @Override
+ public int hashCode() {
+ return Types.this.hashCode(site) & ~msym.hashCode();
+ }
+ }
+
+ public List<MethodSymbol> get(Entry e) {
+ return cache.get(e);
+ }
+
+ public void put(Entry e, List<MethodSymbol> msymbols) {
+ cache.put(e, msymbols);
+ }
+ }
+
+ public CandidatesCache candidatesCache = new CandidatesCache();
+
+ //where
+ public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
+ CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
+ List<MethodSymbol> candidates = candidatesCache.get(e);
+ if (candidates == null) {
+ Filter<Symbol> filter = new MethodFilter(ms, site);
+ List<MethodSymbol> candidates2 = List.nil();
+ for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
+ if (!site.tsym.isInterface() && !s.owner.isInterface()) {
+ return List.of((MethodSymbol)s);
+ } else if (!candidates2.contains(s)) {
+ candidates2 = candidates2.prepend((MethodSymbol)s);
+ }
+ }
+ candidates = prune(candidates2);
+ candidatesCache.put(e, candidates);
+ }
+ return candidates;
+ }
+
+ public List<MethodSymbol> prune(List<MethodSymbol> methods) {
+ ListBuffer<MethodSymbol> methodsMin = new ListBuffer<>();
+ for (MethodSymbol m1 : methods) {
+ boolean isMin_m1 = true;
+ for (MethodSymbol m2 : methods) {
+ if (m1 == m2) continue;
+ if (m2.owner != m1.owner &&
+ asSuper(m2.owner.type, m1.owner) != null) {
+ isMin_m1 = false;
+ break;
+ }
+ }
+ if (isMin_m1)
+ methodsMin.append(m1);
+ }
+ return methodsMin.toList();
+ }
+ // where
+ private class MethodFilter implements Filter<Symbol> {
+
+ Symbol msym;
+ Type site;
+
+ MethodFilter(Symbol msym, Type site) {
+ this.msym = msym;
+ this.site = site;
+ }
+
+ public boolean accepts(Symbol s) {
+ return s.kind == MTH &&
+ s.name == msym.name &&
+ (s.flags() & SYNTHETIC) == 0 &&
+ s.isInheritedIn(site.tsym, Types.this) &&
+ overrideEquivalent(memberType(site, s), memberType(site, msym));
+ }
+ }
+ // </editor-fold>
+
+ /**
+ * Does t have the same arguments as s? It is assumed that both
+ * types are (possibly polymorphic) method types. Monomorphic
+ * method types "have the same arguments", if their argument lists
+ * are equal. Polymorphic method types "have the same arguments",
+ * if they have the same arguments after renaming all type
+ * variables of one to corresponding type variables in the other,
+ * where correspondence is by position in the type parameter list.
+ */
+ public boolean hasSameArgs(Type t, Type s) {
+ return hasSameArgs(t, s, true);
+ }
+
+ public boolean hasSameArgs(Type t, Type s, boolean strict) {
+ return hasSameArgs(t, s, strict ? hasSameArgs_strict : hasSameArgs_nonstrict);
+ }
+
+ private boolean hasSameArgs(Type t, Type s, TypeRelation hasSameArgs) {
+ return hasSameArgs.visit(t, s);
+ }
+ // where
+ private class HasSameArgs extends TypeRelation {
+
+ boolean strict;
+
+ public HasSameArgs(boolean strict) {
+ this.strict = strict;
+ }
+
+ public Boolean visitType(Type t, Type s) {
+ throw new AssertionError();
+ }
+
+ @Override
+ public Boolean visitMethodType(MethodType t, Type s) {
+ return s.hasTag(METHOD)
+ && containsTypeEquivalent(t.argtypes, s.getParameterTypes());
+ }
+
+ @Override
+ public Boolean visitForAll(ForAll t, Type s) {
+ if (!s.hasTag(FORALL))
+ return strict ? false : visitMethodType(t.asMethodType(), s);
+
+ ForAll forAll = (ForAll)s;
+ return hasSameBounds(t, forAll)
+ && visit(t.qtype, subst(forAll.qtype, forAll.tvars, t.tvars));
+ }
+
+ @Override
+ public Boolean visitErrorType(ErrorType t, Type s) {
+ return false;
+ }
+ }
+
+ TypeRelation hasSameArgs_strict = new HasSameArgs(true);
+ TypeRelation hasSameArgs_nonstrict = new HasSameArgs(false);
+
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="subst">
+ public List<Type> subst(List<Type> ts,
+ List<Type> from,
+ List<Type> to) {
+ return ts.map(new Subst(from, to));
+ }
+
+ /**
+ * Substitute all occurrences of a type in `from' with the
+ * corresponding type in `to' in 't'. Match lists `from' and `to'
+ * from the right: If lists have different length, discard leading
+ * elements of the longer list.
+ */
+ public Type subst(Type t, List<Type> from, List<Type> to) {
+ return t.map(new Subst(from, to));
+ }
+
+ private class Subst extends StructuralTypeMapping<Void> {
+ List<Type> from;
+ List<Type> to;
+
+ public Subst(List<Type> from, List<Type> to) {
+ int fromLength = from.length();
+ int toLength = to.length();
+ while (fromLength > toLength) {
+ fromLength--;
+ from = from.tail;
+ }
+ while (fromLength < toLength) {
+ toLength--;
+ to = to.tail;
+ }
+ this.from = from;
+ this.to = to;
+ }
+
+ @Override
+ public Type visitTypeVar(TypeVar t, Void ignored) {
+ for (List<Type> from = this.from, to = this.to;
+ from.nonEmpty();
+ from = from.tail, to = to.tail) {
+ if (t.equalsIgnoreMetadata(from.head)) {
+ return to.head.withTypeVar(t);
+ }
+ }
+ return t;
+ }
+
+ @Override
+ public Type visitClassType(ClassType t, Void ignored) {
+ if (!t.isCompound()) {
+ return super.visitClassType(t, ignored);
+ } else {
+ Type st = visit(supertype(t));
+ List<Type> is = visit(interfaces(t), ignored);
+ if (st == supertype(t) && is == interfaces(t))
+ return t;
+ else
+ return makeIntersectionType(is.prepend(st));
+ }
+ }
+
+ @Override
+ public Type visitWildcardType(WildcardType t, Void ignored) {
+ WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
+ if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
+ t2.type = wildUpperBound(t2.type);
+ }
+ return t2;
+ }
+
+ @Override
+ public Type visitForAll(ForAll t, Void ignored) {
+ if (Type.containsAny(to, t.tvars)) {
+ //perform alpha-renaming of free-variables in 't'
+ //if 'to' types contain variables that are free in 't'
+ List<Type> freevars = newInstances(t.tvars);
+ t = new ForAll(freevars,
+ Types.this.subst(t.qtype, t.tvars, freevars));
+ }
+ List<Type> tvars1 = substBounds(t.tvars, from, to);
+ Type qtype1 = visit(t.qtype);
+ if (tvars1 == t.tvars && qtype1 == t.qtype) {
+ return t;
+ } else if (tvars1 == t.tvars) {
+ return new ForAll(tvars1, qtype1) {
+ @Override
+ public boolean needsStripping() {
+ return true;
+ }
+ };
+ } else {
+ return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
+ @Override
+ public boolean needsStripping() {
+ return true;
+ }
+ };
+ }
+ }
+ }
+
+ public List<Type> substBounds(List<Type> tvars,
+ List<Type> from,
+ List<Type> to) {
+ if (tvars.isEmpty())
+ return tvars;
+ ListBuffer<Type> newBoundsBuf = new ListBuffer<>();
+ boolean changed = false;
+ // calculate new bounds
+ for (Type t : tvars) {
+ TypeVar tv = (TypeVar) t;
+ Type bound = subst(tv.bound, from, to);
+ if (bound != tv.bound)
+ changed = true;
+ newBoundsBuf.append(bound);
+ }
+ if (!changed)
+ return tvars;
+ ListBuffer<Type> newTvars = new ListBuffer<>();
+ // create new type variables without bounds
+ for (Type t : tvars) {
+ newTvars.append(new TypeVar(t.tsym, null, syms.botType,
+ t.getMetadata()));
+ }
+ // the new bounds should use the new type variables in place
+ // of the old
+ List<Type> newBounds = newBoundsBuf.toList();
+ from = tvars;
+ to = newTvars.toList();
+ for (; !newBounds.isEmpty(); newBounds = newBounds.tail) {
+ newBounds.head = subst(newBounds.head, from, to);
+ }
+ newBounds = newBoundsBuf.toList();
+ // set the bounds of new type variables to the new bounds
+ for (Type t : newTvars.toList()) {
+ TypeVar tv = (TypeVar) t;
+ tv.bound = newBounds.head;
+ newBounds = newBounds.tail;
+ }
+ return newTvars.toList();
+ }
+
+ public TypeVar substBound(TypeVar t, List<Type> from, List<Type> to) {
+ Type bound1 = subst(t.bound, from, to);
+ if (bound1 == t.bound)
+ return t;
+ else {
+ // create new type variable without bounds
+ TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
+ t.getMetadata());
+ // the new bound should use the new type variable in place
+ // of the old
+ tv.bound = subst(bound1, List.of(t), List.of(tv));
+ return tv;
+ }
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="hasSameBounds">
+ /**
+ * Does t have the same bounds for quantified variables as s?
+ */
+ public boolean hasSameBounds(ForAll t, ForAll s) {
+ List<Type> l1 = t.tvars;
+ List<Type> l2 = s.tvars;
+ while (l1.nonEmpty() && l2.nonEmpty() &&
+ isSameType(l1.head.getUpperBound(),
+ subst(l2.head.getUpperBound(),
+ s.tvars,
+ t.tvars))) {
+ l1 = l1.tail;
+ l2 = l2.tail;
+ }
+ return l1.isEmpty() && l2.isEmpty();
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="newInstances">
+ /** Create new vector of type variables from list of variables
+ * changing all recursive bounds from old to new list.
+ */
+ public List<Type> newInstances(List<Type> tvars) {
+ List<Type> tvars1 = tvars.map(newInstanceFun);
+ for (List<Type> l = tvars1; l.nonEmpty(); l = l.tail) {
+ TypeVar tv = (TypeVar) l.head;
+ tv.bound = subst(tv.bound, tvars, tvars1);
+ }
+ return tvars1;
+ }
+ private static final TypeMapping<Void> newInstanceFun = new TypeMapping<Void>() {
+ @Override
+ public TypeVar visitTypeVar(TypeVar t, Void _unused) {
+ return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
+ }
+ };
+ // </editor-fold>
+
+ public Type createMethodTypeWithParameters(Type original, List<Type> newParams) {
+ return original.accept(methodWithParameters, newParams);
+ }
+ // where
+ private final MapVisitor<List<Type>> methodWithParameters = new MapVisitor<List<Type>>() {
+ public Type visitType(Type t, List<Type> newParams) {
+ throw new IllegalArgumentException("Not a method type: " + t);
+ }
+ public Type visitMethodType(MethodType t, List<Type> newParams) {
+ return new MethodType(newParams, t.restype, t.thrown, t.tsym);
+ }
+ public Type visitForAll(ForAll t, List<Type> newParams) {
+ return new ForAll(t.tvars, t.qtype.accept(this, newParams));
+ }
+ };
+
+ public Type createMethodTypeWithThrown(Type original, List<Type> newThrown) {
+ return original.accept(methodWithThrown, newThrown);
+ }
+ // where
+ private final MapVisitor<List<Type>> methodWithThrown = new MapVisitor<List<Type>>() {
+ public Type visitType(Type t, List<Type> newThrown) {
+ throw new IllegalArgumentException("Not a method type: " + t);
+ }
+ public Type visitMethodType(MethodType t, List<Type> newThrown) {
+ return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
+ }
+ public Type visitForAll(ForAll t, List<Type> newThrown) {
+ return new ForAll(t.tvars, t.qtype.accept(this, newThrown));
+ }
+ };
+
+ public Type createMethodTypeWithReturn(Type original, Type newReturn) {
+ return original.accept(methodWithReturn, newReturn);
+ }
+ // where
+ private final MapVisitor<Type> methodWithReturn = new MapVisitor<Type>() {
+ public Type visitType(Type t, Type newReturn) {
+ throw new IllegalArgumentException("Not a method type: " + t);
+ }
+ public Type visitMethodType(MethodType t, Type newReturn) {
+ return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
+ @Override
+ public Type baseType() {
+ return t;
+ }
+ };
+ }
+ public Type visitForAll(ForAll t, Type newReturn) {
+ return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
+ @Override
+ public Type baseType() {
+ return t;
+ }
+ };
+ }
+ };
+
+ // <editor-fold defaultstate="collapsed" desc="createErrorType">
+ public Type createErrorType(Type originalType) {
+ return new ErrorType(originalType, syms.errSymbol);
+ }
+
+ public Type createErrorType(ClassSymbol c, Type originalType) {
+ return new ErrorType(c, originalType);
+ }
+
+ public Type createErrorType(Name name, TypeSymbol container, Type originalType) {
+ return new ErrorType(name, container, originalType);
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="rank">
+ /**
+ * The rank of a class is the length of the longest path between
+ * the class and java.lang.Object in the class inheritance
+ * graph. Undefined for all but reference types.
+ */
+ public int rank(Type t) {
+ switch(t.getTag()) {
+ case CLASS: {
+ ClassType cls = (ClassType)t;
+ if (cls.rank_field < 0) {
+ Name fullname = cls.tsym.getQualifiedName();
+ if (fullname == names.java_lang_Object)
+ cls.rank_field = 0;
+ else {
+ int r = rank(supertype(cls));
+ for (List<Type> l = interfaces(cls);
+ l.nonEmpty();
+ l = l.tail) {
+ if (rank(l.head) > r)
+ r = rank(l.head);
+ }
+ cls.rank_field = r + 1;
+ }
+ }
+ return cls.rank_field;
+ }
+ case TYPEVAR: {
+ TypeVar tvar = (TypeVar)t;
+ if (tvar.rank_field < 0) {
+ int r = rank(supertype(tvar));
+ for (List<Type> l = interfaces(tvar);
+ l.nonEmpty();
+ l = l.tail) {
+ if (rank(l.head) > r) r = rank(l.head);
+ }
+ tvar.rank_field = r + 1;
+ }
+ return tvar.rank_field;
+ }
+ case ERROR:
+ case NONE:
+ return 0;
+ default:
+ throw new AssertionError();
+ }
+ }
+ // </editor-fold>
+
+ /**
+ * Helper method for generating a string representation of a given type
+ * accordingly to a given locale
+ */
+ public String toString(Type t, Locale locale) {
+ return Printer.createStandardPrinter(messages).visit(t, locale);
+ }
+
+ /**
+ * Helper method for generating a string representation of a given type
+ * accordingly to a given locale
+ */
+ public String toString(Symbol t, Locale locale) {
+ return Printer.createStandardPrinter(messages).visit(t, locale);
+ }
+
+ // <editor-fold defaultstate="collapsed" desc="toString">
+ /**
+ * This toString is slightly more descriptive than the one on Type.
+ *
+ * @deprecated Types.toString(Type t, Locale l) provides better support
+ * for localization
+ */
+ @Deprecated
+ public String toString(Type t) {
+ if (t.hasTag(FORALL)) {
+ ForAll forAll = (ForAll)t;
+ return typaramsString(forAll.tvars) + forAll.qtype;
+ }
+ return "" + t;
+ }
+ // where
+ private String typaramsString(List<Type> tvars) {
+ StringBuilder s = new StringBuilder();
+ s.append('<');
+ boolean first = true;
+ for (Type t : tvars) {
+ if (!first) s.append(", ");
+ first = false;
+ appendTyparamString(((TypeVar)t), s);
+ }
+ s.append('>');
+ return s.toString();
+ }
+ private void appendTyparamString(TypeVar t, StringBuilder buf) {
+ buf.append(t);
+ if (t.bound == null ||
+ t.bound.tsym.getQualifiedName() == names.java_lang_Object)
+ return;
+ buf.append(" extends "); // Java syntax; no need for i18n
+ Type bound = t.bound;
+ if (!bound.isCompound()) {
+ buf.append(bound);
+ } else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
+ buf.append(supertype(t));
+ for (Type intf : interfaces(t)) {
+ buf.append('&');
+ buf.append(intf);
+ }
+ } else {
+ // No superclass was given in bounds.
+ // In this case, supertype is Object, erasure is first interface.
+ boolean first = true;
+ for (Type intf : interfaces(t)) {
+ if (!first) buf.append('&');
+ first = false;
+ buf.append(intf);
+ }
+ }
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="Determining least upper bounds of types">
+ /**
+ * A cache for closures.
+ *
+ * <p>A closure is a list of all the supertypes and interfaces of
+ * a class or interface type, ordered by ClassSymbol.precedes
+ * (that is, subclasses come first, arbitrary but fixed
+ * otherwise).
+ */
+ private Map<Type,List<Type>> closureCache = new HashMap<>();
+
+ /**
+ * Returns the closure of a class or interface type.
+ */
+ public List<Type> closure(Type t) {
+ List<Type> cl = closureCache.get(t);
+ if (cl == null) {
+ Type st = supertype(t);
+ if (!t.isCompound()) {
+ if (st.hasTag(CLASS)) {
+ cl = insert(closure(st), t);
+ } else if (st.hasTag(TYPEVAR)) {
+ cl = closure(st).prepend(t);
+ } else {
+ cl = List.of(t);
+ }
+ } else {
+ cl = closure(supertype(t));
+ }
+ for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail)
+ cl = union(cl, closure(l.head));
+ closureCache.put(t, cl);
+ }
+ return cl;
+ }
+
+ /**
+ * Collect types into a new closure (using a @code{ClosureHolder})
+ */
+ public Collector<Type, ClosureHolder, List<Type>> closureCollector(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
+ return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
+ ClosureHolder::add,
+ ClosureHolder::merge,
+ ClosureHolder::closure);
+ }
+ //where
+ class ClosureHolder {
+ List<Type> closure;
+ final boolean minClosure;
+ final BiPredicate<Type, Type> shouldSkip;
+
+ ClosureHolder(boolean minClosure, BiPredicate<Type, Type> shouldSkip) {
+ this.closure = List.nil();
+ this.minClosure = minClosure;
+ this.shouldSkip = shouldSkip;
+ }
+
+ void add(Type type) {
+ closure = insert(closure, type, shouldSkip);
+ }
+
+ ClosureHolder merge(ClosureHolder other) {
+ closure = union(closure, other.closure, shouldSkip);
+ return this;
+ }
+
+ List<Type> closure() {
+ return minClosure ? closureMin(closure) : closure;
+ }
+ }
+
+ BiPredicate<Type, Type> basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
+
+ /**
+ * Insert a type in a closure
+ */
+ public List<Type> insert(List<Type> cl, Type t, BiPredicate<Type, Type> shouldSkip) {
+ if (cl.isEmpty()) {
+ return cl.prepend(t);
+ } else if (shouldSkip.test(t, cl.head)) {
+ return cl;
+ } else if (t.tsym.precedes(cl.head.tsym, this)) {
+ return cl.prepend(t);
+ } else {
+ // t comes after head, or the two are unrelated
+ return insert(cl.tail, t, shouldSkip).prepend(cl.head);
+ }
+ }
+
+ public List<Type> insert(List<Type> cl, Type t) {
+ return insert(cl, t, basicClosureSkip);
+ }
+
+ /**
+ * Form the union of two closures
+ */
+ public List<Type> union(List<Type> cl1, List<Type> cl2, BiPredicate<Type, Type> shouldSkip) {
+ if (cl1.isEmpty()) {
+ return cl2;
+ } else if (cl2.isEmpty()) {
+ return cl1;
+ } else if (shouldSkip.test(cl1.head, cl2.head)) {
+ return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
+ } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
+ return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
+ } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
+ return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
+ } else {
+ // unrelated types
+ return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
+ }
+ }
+
+ public List<Type> union(List<Type> cl1, List<Type> cl2) {
+ return union(cl1, cl2, basicClosureSkip);
+ }
+
+ /**
+ * Intersect two closures
+ */
+ public List<Type> intersect(List<Type> cl1, List<Type> cl2) {
+ if (cl1 == cl2)
+ return cl1;
+ if (cl1.isEmpty() || cl2.isEmpty())
+ return List.nil();
+ if (cl1.head.tsym.precedes(cl2.head.tsym, this))
+ return intersect(cl1.tail, cl2);
+ if (cl2.head.tsym.precedes(cl1.head.tsym, this))
+ return intersect(cl1, cl2.tail);
+ if (isSameType(cl1.head, cl2.head))
+ return intersect(cl1.tail, cl2.tail).prepend(cl1.head);
+ if (cl1.head.tsym == cl2.head.tsym &&
+ cl1.head.hasTag(CLASS) && cl2.head.hasTag(CLASS)) {
+ if (cl1.head.isParameterized() && cl2.head.isParameterized()) {
+ Type merge = merge(cl1.head,cl2.head);
+ return intersect(cl1.tail, cl2.tail).prepend(merge);
+ }
+ if (cl1.head.isRaw() || cl2.head.isRaw())
+ return intersect(cl1.tail, cl2.tail).prepend(erasure(cl1.head));
+ }
+ return intersect(cl1.tail, cl2.tail);
+ }
+ // where
+ class TypePair {
+ final Type t1;
+ final Type t2;
+ boolean strict;
+
+ TypePair(Type t1, Type t2) {
+ this(t1, t2, false);
+ }
+
+ TypePair(Type t1, Type t2, boolean strict) {
+ this.t1 = t1;
+ this.t2 = t2;
+ this.strict = strict;
+ }
+ @Override
+ public int hashCode() {
+ return 127 * Types.this.hashCode(t1) + Types.this.hashCode(t2);
+ }
+ @Override
+ public boolean equals(Object obj) {
+ if (!(obj instanceof TypePair))
+ return false;
+ TypePair typePair = (TypePair)obj;
+ return isSameType(t1, typePair.t1, strict)
+ && isSameType(t2, typePair.t2, strict);
+ }
+ }
+ Set<TypePair> mergeCache = new HashSet<>();
+ private Type merge(Type c1, Type c2) {
+ ClassType class1 = (ClassType) c1;
+ List<Type> act1 = class1.getTypeArguments();
+ ClassType class2 = (ClassType) c2;
+ List<Type> act2 = class2.getTypeArguments();
+ ListBuffer<Type> merged = new ListBuffer<>();
+ List<Type> typarams = class1.tsym.type.getTypeArguments();
+
+ while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
+ if (containsType(act1.head, act2.head)) {
+ merged.append(act1.head);
+ } else if (containsType(act2.head, act1.head)) {
+ merged.append(act2.head);
+ } else {
+ TypePair pair = new TypePair(c1, c2);
+ Type m;
+ if (mergeCache.add(pair)) {
+ m = new WildcardType(lub(wildUpperBound(act1.head),
+ wildUpperBound(act2.head)),
+ BoundKind.EXTENDS,
+ syms.boundClass);
+ mergeCache.remove(pair);
+ } else {
+ m = new WildcardType(syms.objectType,
+ BoundKind.UNBOUND,
+ syms.boundClass);
+ }
+ merged.append(m.withTypeVar(typarams.head));
+ }
+ act1 = act1.tail;
+ act2 = act2.tail;
+ typarams = typarams.tail;
+ }
+ Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
+ // There is no spec detailing how type annotations are to
+ // be inherited. So set it to noAnnotations for now
+ return new ClassType(class1.getEnclosingType(), merged.toList(),
+ class1.tsym);
+ }
+
+ /**
+ * Return the minimum type of a closure, a compound type if no
+ * unique minimum exists.
+ */
+ private Type compoundMin(List<Type> cl) {
+ if (cl.isEmpty()) return syms.objectType;
+ List<Type> compound = closureMin(cl);
+ if (compound.isEmpty())
+ return null;
+ else if (compound.tail.isEmpty())
+ return compound.head;
+ else
+ return makeIntersectionType(compound);
+ }
+
+ /**
+ * Return the minimum types of a closure, suitable for computing
+ * compoundMin or glb.
+ */
+ private List<Type> closureMin(List<Type> cl) {
+ ListBuffer<Type> classes = new ListBuffer<>();
+ ListBuffer<Type> interfaces = new ListBuffer<>();
+ Set<Type> toSkip = new HashSet<>();
+ while (!cl.isEmpty()) {
+ Type current = cl.head;
+ boolean keep = !toSkip.contains(current);
+ if (keep && current.hasTag(TYPEVAR)) {
+ // skip lower-bounded variables with a subtype in cl.tail
+ for (Type t : cl.tail) {
+ if (isSubtypeNoCapture(t, current)) {
+ keep = false;
+ break;
+ }
+ }
+ }
+ if (keep) {
+ if (current.isInterface())
+ interfaces.append(current);
+ else
+ classes.append(current);
+ for (Type t : cl.tail) {
+ // skip supertypes of 'current' in cl.tail
+ if (isSubtypeNoCapture(current, t))
+ toSkip.add(t);
+ }
+ }
+ cl = cl.tail;
+ }
+ return classes.appendList(interfaces).toList();
+ }
+
+ /**
+ * Return the least upper bound of list of types. if the lub does
+ * not exist return null.
+ */
+ public Type lub(List<Type> ts) {
+ return lub(ts.toArray(new Type[ts.length()]));
+ }
+
+ /**
+ * Return the least upper bound (lub) of set of types. If the lub
+ * does not exist return the type of null (bottom).
+ */
+ public Type lub(Type... ts) {
+ final int UNKNOWN_BOUND = 0;
+ final int ARRAY_BOUND = 1;
+ final int CLASS_BOUND = 2;
+
+ int[] kinds = new int[ts.length];
+
+ int boundkind = UNKNOWN_BOUND;
+ for (int i = 0 ; i < ts.length ; i++) {
+ Type t = ts[i];
+ switch (t.getTag()) {
+ case CLASS:
+ boundkind |= kinds[i] = CLASS_BOUND;
+ break;
+ case ARRAY:
+ boundkind |= kinds[i] = ARRAY_BOUND;
+ break;
+ case TYPEVAR:
+ do {
+ t = t.getUpperBound();
+ } while (t.hasTag(TYPEVAR));
+ if (t.hasTag(ARRAY)) {
+ boundkind |= kinds[i] = ARRAY_BOUND;
+ } else {
+ boundkind |= kinds[i] = CLASS_BOUND;
+ }
+ break;
+ default:
+ kinds[i] = UNKNOWN_BOUND;
+ if (t.isPrimitive())
+ return syms.errType;
+ }
+ }
+ switch (boundkind) {
+ case 0:
+ return syms.botType;
+
+ case ARRAY_BOUND:
+ // calculate lub(A[], B[])
+ Type[] elements = new Type[ts.length];
+ for (int i = 0 ; i < ts.length ; i++) {
+ Type elem = elements[i] = elemTypeFun.apply(ts[i]);
+ if (elem.isPrimitive()) {
+ // if a primitive type is found, then return
+ // arraySuperType unless all the types are the
+ // same
+ Type first = ts[0];
+ for (int j = 1 ; j < ts.length ; j++) {
+ if (!isSameType(first, ts[j])) {
+ // lub(int[], B[]) is Cloneable & Serializable
+ return arraySuperType();
+ }
+ }
+ // all the array types are the same, return one
+ // lub(int[], int[]) is int[]
+ return first;
+ }
+ }
+ // lub(A[], B[]) is lub(A, B)[]
+ return new ArrayType(lub(elements), syms.arrayClass);
+
+ case CLASS_BOUND:
+ // calculate lub(A, B)
+ int startIdx = 0;
+ for (int i = 0; i < ts.length ; i++) {
+ Type t = ts[i];
+ if (t.hasTag(CLASS) || t.hasTag(TYPEVAR)) {
+ break;
+ } else {
+ startIdx++;
+ }
+ }
+ Assert.check(startIdx < ts.length);
+ //step 1 - compute erased candidate set (EC)
+ List<Type> cl = erasedSupertypes(ts[startIdx]);
+ for (int i = startIdx + 1 ; i < ts.length ; i++) {
+ Type t = ts[i];
+ if (t.hasTag(CLASS) || t.hasTag(TYPEVAR))
+ cl = intersect(cl, erasedSupertypes(t));
+ }
+ //step 2 - compute minimal erased candidate set (MEC)
+ List<Type> mec = closureMin(cl);
+ //step 3 - for each element G in MEC, compute lci(Inv(G))
+ List<Type> candidates = List.nil();
+ for (Type erasedSupertype : mec) {
+ List<Type> lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
+ for (int i = startIdx + 1 ; i < ts.length ; i++) {
+ Type superType = asSuper(ts[i], erasedSupertype.tsym);
+ lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
+ }
+ candidates = candidates.appendList(lci);
+ }
+ //step 4 - let MEC be { G1, G2 ... Gn }, then we have that
+ //lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
+ return compoundMin(candidates);
+
+ default:
+ // calculate lub(A, B[])
+ List<Type> classes = List.of(arraySuperType());
+ for (int i = 0 ; i < ts.length ; i++) {
+ if (kinds[i] != ARRAY_BOUND) // Filter out any arrays
+ classes = classes.prepend(ts[i]);
+ }
+ // lub(A, B[]) is lub(A, arraySuperType)
+ return lub(classes);
+ }
+ }
+ // where
+ List<Type> erasedSupertypes(Type t) {
+ ListBuffer<Type> buf = new ListBuffer<>();
+ for (Type sup : closure(t)) {
+ if (sup.hasTag(TYPEVAR)) {
+ buf.append(sup);
+ } else {
+ buf.append(erasure(sup));
+ }
+ }
+ return buf.toList();
+ }
+
+ private Type arraySuperType = null;
+ private Type arraySuperType() {
+ // initialized lazily to avoid problems during compiler startup
+ if (arraySuperType == null) {
+ synchronized (this) {
+ if (arraySuperType == null) {
+ // JLS 10.8: all arrays implement Cloneable and Serializable.
+ arraySuperType = makeIntersectionType(List.of(syms.serializableType,
+ syms.cloneableType), true);
+ }
+ }
+ }
+ return arraySuperType;
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="Greatest lower bound">
+ public Type glb(List<Type> ts) {
+ Type t1 = ts.head;
+ for (Type t2 : ts.tail) {
+ if (t1.isErroneous())
+ return t1;
+ t1 = glb(t1, t2);
+ }
+ return t1;
+ }
+ //where
+ public Type glb(Type t, Type s) {
+ if (s == null)
+ return t;
+ else if (t.isPrimitive() || s.isPrimitive())
+ return syms.errType;
+ else if (isSubtypeNoCapture(t, s))
+ return t;
+ else if (isSubtypeNoCapture(s, t))
+ return s;
+
+ List<Type> closure = union(closure(t), closure(s));
+ return glbFlattened(closure, t);
+ }
+ //where
+ /**
+ * Perform glb for a list of non-primitive, non-error, non-compound types;
+ * redundant elements are removed. Bounds should be ordered according to
+ * {@link Symbol#precedes(TypeSymbol,Types)}.
+ *
+ * @param flatBounds List of type to glb
+ * @param errT Original type to use if the result is an error type
+ */
+ private Type glbFlattened(List<Type> flatBounds, Type errT) {
+ List<Type> bounds = closureMin(flatBounds);
+
+ if (bounds.isEmpty()) { // length == 0
+ return syms.objectType;
+ } else if (bounds.tail.isEmpty()) { // length == 1
+ return bounds.head;
+ } else { // length > 1
+ int classCount = 0;
+ List<Type> cvars = List.nil();
+ List<Type> lowers = List.nil();
+ for (Type bound : bounds) {
+ if (!bound.isInterface()) {
+ classCount++;
+ Type lower = cvarLowerBound(bound);
+ if (bound != lower && !lower.hasTag(BOT)) {
+ cvars = cvars.append(bound);
+ lowers = lowers.append(lower);
+ }
+ }
+ }
+ if (classCount > 1) {
+ if (lowers.isEmpty()) {
+ return createErrorType(errT);
+ } else {
+ // try again with lower bounds included instead of capture variables
+ List<Type> newBounds = bounds.diff(cvars).appendList(lowers);
+ return glb(newBounds);
+ }
+ }
+ }
+ return makeIntersectionType(bounds);
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="hashCode">
+ /**
+ * Compute a hash code on a type.
+ */
+ public int hashCode(Type t) {
+ return hashCode(t, false);
+ }
+
+ public int hashCode(Type t, boolean strict) {
+ return strict ?
+ hashCodeStrictVisitor.visit(t) :
+ hashCodeVisitor.visit(t);
+ }
+ // where
+ private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
+ private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
+ @Override
+ public Integer visitTypeVar(TypeVar t, Void ignored) {
+ return System.identityHashCode(t);
+ }
+ };
+
+ private static class HashCodeVisitor extends UnaryVisitor<Integer> {
+ public Integer visitType(Type t, Void ignored) {
+ return t.getTag().ordinal();
+ }
+
+ @Override
+ public Integer visitClassType(ClassType t, Void ignored) {
+ int result = visit(t.getEnclosingType());
+ result *= 127;
+ result += t.tsym.flatName().hashCode();
+ for (Type s : t.getTypeArguments()) {
+ result *= 127;
+ result += visit(s);
+ }
+ return result;
+ }
+
+ @Override
+ public Integer visitMethodType(MethodType t, Void ignored) {
+ int h = METHOD.ordinal();
+ for (List<Type> thisargs = t.argtypes;
+ thisargs.tail != null;
+ thisargs = thisargs.tail)
+ h = (h << 5) + visit(thisargs.head);
+ return (h << 5) + visit(t.restype);
+ }
+
+ @Override
+ public Integer visitWildcardType(WildcardType t, Void ignored) {
+ int result = t.kind.hashCode();
+ if (t.type != null) {
+ result *= 127;
+ result += visit(t.type);
+ }
+ return result;
+ }
+
+ @Override
+ public Integer visitArrayType(ArrayType t, Void ignored) {
+ return visit(t.elemtype) + 12;
+ }
+
+ @Override
+ public Integer visitTypeVar(TypeVar t, Void ignored) {
+ return System.identityHashCode(t);
+ }
+
+ @Override
+ public Integer visitUndetVar(UndetVar t, Void ignored) {
+ return System.identityHashCode(t);
+ }
+
+ @Override
+ public Integer visitErrorType(ErrorType t, Void ignored) {
+ return 0;
+ }
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="Return-Type-Substitutable">
+ /**
+ * Does t have a result that is a subtype of the result type of s,
+ * suitable for covariant returns? It is assumed that both types
+ * are (possibly polymorphic) method types. Monomorphic method
+ * types are handled in the obvious way. Polymorphic method types
+ * require renaming all type variables of one to corresponding
+ * type variables in the other, where correspondence is by
+ * position in the type parameter list. */
+ public boolean resultSubtype(Type t, Type s, Warner warner) {
+ List<Type> tvars = t.getTypeArguments();
+ List<Type> svars = s.getTypeArguments();
+ Type tres = t.getReturnType();
+ Type sres = subst(s.getReturnType(), svars, tvars);
+ return covariantReturnType(tres, sres, warner);
+ }
+
+ /**
+ * Return-Type-Substitutable.
+ * @jls section 8.4.5
+ */
+ public boolean returnTypeSubstitutable(Type r1, Type r2) {
+ if (hasSameArgs(r1, r2))
+ return resultSubtype(r1, r2, noWarnings);
+ else
+ return covariantReturnType(r1.getReturnType(),
+ erasure(r2.getReturnType()),
+ noWarnings);
+ }
+
+ public boolean returnTypeSubstitutable(Type r1,
+ Type r2, Type r2res,
+ Warner warner) {
+ if (isSameType(r1.getReturnType(), r2res))
+ return true;
+ if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
+ return false;
+
+ if (hasSameArgs(r1, r2))
+ return covariantReturnType(r1.getReturnType(), r2res, warner);
+ if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
+ return true;
+ if (!isSubtype(r1.getReturnType(), erasure(r2res)))
+ return false;
+ warner.warn(LintCategory.UNCHECKED);
+ return true;
+ }
+
+ /**
+ * Is t an appropriate return type in an overrider for a
+ * method that returns s?
+ */
+ public boolean covariantReturnType(Type t, Type s, Warner warner) {
+ return
+ isSameType(t, s) ||
+ !t.isPrimitive() &&
+ !s.isPrimitive() &&
+ isAssignable(t, s, warner);
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="Box/unbox support">
+ /**
+ * Return the class that boxes the given primitive.
+ */
+ public ClassSymbol boxedClass(Type t) {
+ return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
+ }
+
+ /**
+ * Return the boxed type if 't' is primitive, otherwise return 't' itself.
+ */
+ public Type boxedTypeOrType(Type t) {
+ return t.isPrimitive() ?
+ boxedClass(t).type :
+ t;
+ }
+
+ /**
+ * Return the primitive type corresponding to a boxed type.
+ */
+ public Type unboxedType(Type t) {
+ for (int i=0; i<syms.boxedName.length; i++) {
+ Name box = syms.boxedName[i];
+ if (box != null &&
+ asSuper(t, syms.enterClass(syms.java_base, box)) != null)
+ return syms.typeOfTag[i];
+ }
+ return Type.noType;
+ }
+
+ /**
+ * Return the unboxed type if 't' is a boxed class, otherwise return 't' itself.
+ */
+ public Type unboxedTypeOrType(Type t) {
+ Type unboxedType = unboxedType(t);
+ return unboxedType.hasTag(NONE) ? t : unboxedType;
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="Capture conversion">
+ /*
+ * JLS 5.1.10 Capture Conversion:
+ *
+ * Let G name a generic type declaration with n formal type
+ * parameters A1 ... An with corresponding bounds U1 ... Un. There
+ * exists a capture conversion from G<T1 ... Tn> to G<S1 ... Sn>,
+ * where, for 1 <= i <= n:
+ *
+ * + If Ti is a wildcard type argument (4.5.1) of the form ? then
+ * Si is a fresh type variable whose upper bound is
+ * Ui[A1 := S1, ..., An := Sn] and whose lower bound is the null
+ * type.
+ *
+ * + If Ti is a wildcard type argument of the form ? extends Bi,
+ * then Si is a fresh type variable whose upper bound is
+ * glb(Bi, Ui[A1 := S1, ..., An := Sn]) and whose lower bound is
+ * the null type, where glb(V1,... ,Vm) is V1 & ... & Vm. It is
+ * a compile-time error if for any two classes (not interfaces)
+ * Vi and Vj,Vi is not a subclass of Vj or vice versa.
+ *
+ * + If Ti is a wildcard type argument of the form ? super Bi,
+ * then Si is a fresh type variable whose upper bound is
+ * Ui[A1 := S1, ..., An := Sn] and whose lower bound is Bi.
+ *
+ * + Otherwise, Si = Ti.
+ *
+ * Capture conversion on any type other than a parameterized type
+ * (4.5) acts as an identity conversion (5.1.1). Capture
+ * conversions never require a special action at run time and
+ * therefore never throw an exception at run time.
+ *
+ * Capture conversion is not applied recursively.
+ */
+ /**
+ * Capture conversion as specified by the JLS.
+ */
+
+ public List<Type> capture(List<Type> ts) {
+ List<Type> buf = List.nil();
+ for (Type t : ts) {
+ buf = buf.prepend(capture(t));
+ }
+ return buf.reverse();
+ }
+
+ public Type capture(Type t) {
+ if (!t.hasTag(CLASS)) {
+ return t;
+ }
+ if (t.getEnclosingType() != Type.noType) {
+ Type capturedEncl = capture(t.getEnclosingType());
+ if (capturedEncl != t.getEnclosingType()) {
+ Type type1 = memberType(capturedEncl, t.tsym);
+ t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
+ }
+ }
+ ClassType cls = (ClassType)t;
+ if (cls.isRaw() || !cls.isParameterized())
+ return cls;
+
+ ClassType G = (ClassType)cls.asElement().asType();
+ List<Type> A = G.getTypeArguments();
+ List<Type> T = cls.getTypeArguments();
+ List<Type> S = freshTypeVariables(T);
+
+ List<Type> currentA = A;
+ List<Type> currentT = T;
+ List<Type> currentS = S;
+ boolean captured = false;
+ while (!currentA.isEmpty() &&
+ !currentT.isEmpty() &&
+ !currentS.isEmpty()) {
+ if (currentS.head != currentT.head) {
+ captured = true;
+ WildcardType Ti = (WildcardType)currentT.head;
+ Type Ui = currentA.head.getUpperBound();
+ CapturedType Si = (CapturedType)currentS.head;
+ if (Ui == null)
+ Ui = syms.objectType;
+ switch (Ti.kind) {
+ case UNBOUND:
+ Si.bound = subst(Ui, A, S);
+ Si.lower = syms.botType;
+ break;
+ case EXTENDS:
+ Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
+ Si.lower = syms.botType;
+ break;
+ case SUPER:
+ Si.bound = subst(Ui, A, S);
+ Si.lower = Ti.getSuperBound();
+ break;
+ }
+ Type tmpBound = Si.bound.hasTag(UNDETVAR) ? ((UndetVar)Si.bound).qtype : Si.bound;
+ Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
+ if (!Si.bound.hasTag(ERROR) &&
+ !Si.lower.hasTag(ERROR) &&
+ isSameType(tmpBound, tmpLower, false)) {
+ currentS.head = Si.bound;
+ }
+ }
+ currentA = currentA.tail;
+ currentT = currentT.tail;
+ currentS = currentS.tail;
+ }
+ if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
+ return erasure(t); // some "rare" type involved
+
+ if (captured)
+ return new ClassType(cls.getEnclosingType(), S, cls.tsym,
+ cls.getMetadata());
+ else
+ return t;
+ }
+ // where
+ public List<Type> freshTypeVariables(List<Type> types) {
+ ListBuffer<Type> result = new ListBuffer<>();
+ for (Type t : types) {
+ if (t.hasTag(WILDCARD)) {
+ Type bound = ((WildcardType)t).getExtendsBound();
+ if (bound == null)
+ bound = syms.objectType;
+ result.append(new CapturedType(capturedName,
+ syms.noSymbol,
+ bound,
+ syms.botType,
+ (WildcardType)t));
+ } else {
+ result.append(t);
+ }
+ }
+ return result.toList();
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="Internal utility methods">
+ private boolean sideCast(Type from, Type to, Warner warn) {
+ // We are casting from type $from$ to type $to$, which are
+ // non-final unrelated types. This method
+ // tries to reject a cast by transferring type parameters
+ // from $to$ to $from$ by common superinterfaces.
+ boolean reverse = false;
+ Type target = to;
+ if ((to.tsym.flags() & INTERFACE) == 0) {
+ Assert.check((from.tsym.flags() & INTERFACE) != 0);
+ reverse = true;
+ to = from;
+ from = target;
+ }
+ List<Type> commonSupers = superClosure(to, erasure(from));
+ boolean giveWarning = commonSupers.isEmpty();
+ // The arguments to the supers could be unified here to
+ // get a more accurate analysis
+ while (commonSupers.nonEmpty()) {
+ Type t1 = asSuper(from, commonSupers.head.tsym);
+ Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
+ if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
+ return false;
+ giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
+ commonSupers = commonSupers.tail;
+ }
+ if (giveWarning && !isReifiable(reverse ? from : to))
+ warn.warn(LintCategory.UNCHECKED);
+ return true;
+ }
+
+ private boolean sideCastFinal(Type from, Type to, Warner warn) {
+ // We are casting from type $from$ to type $to$, which are
+ // unrelated types one of which is final and the other of
+ // which is an interface. This method
+ // tries to reject a cast by transferring type parameters
+ // from the final class to the interface.
+ boolean reverse = false;
+ Type target = to;
+ if ((to.tsym.flags() & INTERFACE) == 0) {
+ Assert.check((from.tsym.flags() & INTERFACE) != 0);
+ reverse = true;
+ to = from;
+ from = target;
+ }
+ Assert.check((from.tsym.flags() & FINAL) != 0);
+ Type t1 = asSuper(from, to.tsym);
+ if (t1 == null) return false;
+ Type t2 = to;
+ if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
+ return false;
+ if (!isReifiable(target) &&
+ (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
+ warn.warn(LintCategory.UNCHECKED);
+ return true;
+ }
+
+ private boolean giveWarning(Type from, Type to) {
+ List<Type> bounds = to.isCompound() ?
+ directSupertypes(to) : List.of(to);
+ for (Type b : bounds) {
+ Type subFrom = asSub(from, b.tsym);
+ if (b.isParameterized() &&
+ (!(isUnbounded(b) ||
+ isSubtype(from, b) ||
+ ((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
+ return true;
+ }
+ }
+ return false;
+ }
+
+ private List<Type> superClosure(Type t, Type s) {
+ List<Type> cl = List.nil();
+ for (List<Type> l = interfaces(t); l.nonEmpty(); l = l.tail) {
+ if (isSubtype(s, erasure(l.head))) {
+ cl = insert(cl, l.head);
+ } else {
+ cl = union(cl, superClosure(l.head, s));
+ }
+ }
+ return cl;
+ }
+
+ private boolean containsTypeEquivalent(Type t, Type s) {
+ return isSameType(t, s) || // shortcut
+ containsType(t, s) && containsType(s, t);
+ }
+
+ // <editor-fold defaultstate="collapsed" desc="adapt">
+ /**
+ * Adapt a type by computing a substitution which maps a source
+ * type to a target type.
+ *
+ * @param source the source type
+ * @param target the target type
+ * @param from the type variables of the computed substitution
+ * @param to the types of the computed substitution.
+ */
+ public void adapt(Type source,
+ Type target,
+ ListBuffer<Type> from,
+ ListBuffer<Type> to) throws AdaptFailure {
+ new Adapter(from, to).adapt(source, target);
+ }
+
+ class Adapter extends SimpleVisitor<Void, Type> {
+
+ ListBuffer<Type> from;
+ ListBuffer<Type> to;
+ Map<Symbol,Type> mapping;
+
+ Adapter(ListBuffer<Type> from, ListBuffer<Type> to) {
+ this.from = from;
+ this.to = to;
+ mapping = new HashMap<>();
+ }
+
+ public void adapt(Type source, Type target) throws AdaptFailure {
+ visit(source, target);
+ List<Type> fromList = from.toList();
+ List<Type> toList = to.toList();
+ while (!fromList.isEmpty()) {
+ Type val = mapping.get(fromList.head.tsym);
+ if (toList.head != val)
+ toList.head = val;
+ fromList = fromList.tail;
+ toList = toList.tail;
+ }
+ }
+
+ @Override
+ public Void visitClassType(ClassType source, Type target) throws AdaptFailure {
+ if (target.hasTag(CLASS))
+ adaptRecursive(source.allparams(), target.allparams());
+ return null;
+ }
+
+ @Override
+ public Void visitArrayType(ArrayType source, Type target) throws AdaptFailure {
+ if (target.hasTag(ARRAY))
+ adaptRecursive(elemtype(source), elemtype(target));
+ return null;
+ }
+
+ @Override
+ public Void visitWildcardType(WildcardType source, Type target) throws AdaptFailure {
+ if (source.isExtendsBound())
+ adaptRecursive(wildUpperBound(source), wildUpperBound(target));
+ else if (source.isSuperBound())
+ adaptRecursive(wildLowerBound(source), wildLowerBound(target));
+ return null;
+ }
+
+ @Override
+ public Void visitTypeVar(TypeVar source, Type target) throws AdaptFailure {
+ // Check to see if there is
+ // already a mapping for $source$, in which case
+ // the old mapping will be merged with the new
+ Type val = mapping.get(source.tsym);
+ if (val != null) {
+ if (val.isSuperBound() && target.isSuperBound()) {
+ val = isSubtype(wildLowerBound(val), wildLowerBound(target))
+ ? target : val;
+ } else if (val.isExtendsBound() && target.isExtendsBound()) {
+ val = isSubtype(wildUpperBound(val), wildUpperBound(target))
+ ? val : target;
+ } else if (!isSameType(val, target)) {
+ throw new AdaptFailure();
+ }
+ } else {
+ val = target;
+ from.append(source);
+ to.append(target);
+ }
+ mapping.put(source.tsym, val);
+ return null;
+ }
+
+ @Override
+ public Void visitType(Type source, Type target) {
+ return null;
+ }
+
+ private Set<TypePair> cache = new HashSet<>();
+
+ private void adaptRecursive(Type source, Type target) {
+ TypePair pair = new TypePair(source, target);
+ if (cache.add(pair)) {
+ try {
+ visit(source, target);
+ } finally {
+ cache.remove(pair);
+ }
+ }
+ }
+
+ private void adaptRecursive(List<Type> source, List<Type> target) {
+ if (source.length() == target.length()) {
+ while (source.nonEmpty()) {
+ adaptRecursive(source.head, target.head);
+ source = source.tail;
+ target = target.tail;
+ }
+ }
+ }
+ }
+
+ public static class AdaptFailure extends RuntimeException {
+ static final long serialVersionUID = -7490231548272701566L;
+ }
+
+ private void adaptSelf(Type t,
+ ListBuffer<Type> from,
+ ListBuffer<Type> to) {
+ try {
+ //if (t.tsym.type != t)
+ adapt(t.tsym.type, t, from, to);
+ } catch (AdaptFailure ex) {
+ // Adapt should never fail calculating a mapping from
+ // t.tsym.type to t as there can be no merge problem.
+ throw new AssertionError(ex);
+ }
+ }
+ // </editor-fold>
+
+ /**
+ * Rewrite all type variables (universal quantifiers) in the given
+ * type to wildcards (existential quantifiers). This is used to
+ * determine if a cast is allowed. For example, if high is true
+ * and {@code T <: Number}, then {@code List<T>} is rewritten to
+ * {@code List<? extends Number>}. Since {@code List<Integer> <:
+ * List<? extends Number>} a {@code List<T>} can be cast to {@code
+ * List<Integer>} with a warning.
+ * @param t a type
+ * @param high if true return an upper bound; otherwise a lower
+ * bound
+ * @param rewriteTypeVars only rewrite captured wildcards if false;
+ * otherwise rewrite all type variables
+ * @return the type rewritten with wildcards (existential
+ * quantifiers) only
+ */
+ private Type rewriteQuantifiers(Type t, boolean high, boolean rewriteTypeVars) {
+ return new Rewriter(high, rewriteTypeVars).visit(t);
+ }
+
+ class Rewriter extends UnaryVisitor<Type> {
+
+ boolean high;
+ boolean rewriteTypeVars;
+
+ Rewriter(boolean high, boolean rewriteTypeVars) {
+ this.high = high;
+ this.rewriteTypeVars = rewriteTypeVars;
+ }
+
+ @Override
+ public Type visitClassType(ClassType t, Void s) {
+ ListBuffer<Type> rewritten = new ListBuffer<>();
+ boolean changed = false;
+ for (Type arg : t.allparams()) {
+ Type bound = visit(arg);
+ if (arg != bound) {
+ changed = true;
+ }
+ rewritten.append(bound);
+ }
+ if (changed)
+ return subst(t.tsym.type,
+ t.tsym.type.allparams(),
+ rewritten.toList());
+ else
+ return t;
+ }
+
+ public Type visitType(Type t, Void s) {
+ return t;
+ }
+
+ @Override
+ public Type visitCapturedType(CapturedType t, Void s) {
+ Type w_bound = t.wildcard.type;
+ Type bound = w_bound.contains(t) ?
+ erasure(w_bound) :
+ visit(w_bound);
+ return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
+ }
+
+ @Override
+ public Type visitTypeVar(TypeVar t, Void s) {
+ if (rewriteTypeVars) {
+ Type bound = t.bound.contains(t) ?
+ erasure(t.bound) :
+ visit(t.bound);
+ return rewriteAsWildcardType(bound, t, EXTENDS);
+ } else {
+ return t;
+ }
+ }
+
+ @Override
+ public Type visitWildcardType(WildcardType t, Void s) {
+ Type bound2 = visit(t.type);
+ return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
+ }
+
+ private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
+ switch (bk) {
+ case EXTENDS: return high ?
+ makeExtendsWildcard(B(bound), formal) :
+ makeExtendsWildcard(syms.objectType, formal);
+ case SUPER: return high ?
+ makeSuperWildcard(syms.botType, formal) :
+ makeSuperWildcard(B(bound), formal);
+ case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
+ default:
+ Assert.error("Invalid bound kind " + bk);
+ return null;
+ }
+ }
+
+ Type B(Type t) {
+ while (t.hasTag(WILDCARD)) {
+ WildcardType w = (WildcardType)t;
+ t = high ?
+ w.getExtendsBound() :
+ w.getSuperBound();
+ if (t == null) {
+ t = high ? syms.objectType : syms.botType;
+ }
+ }
+ return t;
+ }
+ }
+
+
+ /**
+ * Create a wildcard with the given upper (extends) bound; create
+ * an unbounded wildcard if bound is Object.
+ *
+ * @param bound the upper bound
+ * @param formal the formal type parameter that will be
+ * substituted by the wildcard
+ */
+ private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
+ if (bound == syms.objectType) {
+ return new WildcardType(syms.objectType,
+ BoundKind.UNBOUND,
+ syms.boundClass,
+ formal);
+ } else {
+ return new WildcardType(bound,
+ BoundKind.EXTENDS,
+ syms.boundClass,
+ formal);
+ }
+ }
+
+ /**
+ * Create a wildcard with the given lower (super) bound; create an
+ * unbounded wildcard if bound is bottom (type of {@code null}).
+ *
+ * @param bound the lower bound
+ * @param formal the formal type parameter that will be
+ * substituted by the wildcard
+ */
+ private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
+ if (bound.hasTag(BOT)) {
+ return new WildcardType(syms.objectType,
+ BoundKind.UNBOUND,
+ syms.boundClass,
+ formal);
+ } else {
+ return new WildcardType(bound,
+ BoundKind.SUPER,
+ syms.boundClass,
+ formal);
+ }
+ }
+
+ /**
+ * A wrapper for a type that allows use in sets.
+ */
+ public static class UniqueType {
+ public final Type type;
+ final Types types;
+
+ public UniqueType(Type type, Types types) {
+ this.type = type;
+ this.types = types;
+ }
+
+ public int hashCode() {
+ return types.hashCode(type);
+ }
+
+ public boolean equals(Object obj) {
+ return (obj instanceof UniqueType) &&
+ types.isSameType(type, ((UniqueType)obj).type);
+ }
+
+ public String toString() {
+ return type.toString();
+ }
+
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="Visitors">
+ /**
+ * A default visitor for types. All visitor methods except
+ * visitType are implemented by delegating to visitType. Concrete
+ * subclasses must provide an implementation of visitType and can
+ * override other methods as needed.
+ *
+ * @param <R> the return type of the operation implemented by this
+ * visitor; use Void if no return type is needed.
+ * @param <S> the type of the second argument (the first being the
+ * type itself) of the operation implemented by this visitor; use
+ * Void if a second argument is not needed.
+ */
+ public static abstract class DefaultTypeVisitor<R,S> implements Type.Visitor<R,S> {
+ final public R visit(Type t, S s) { return t.accept(this, s); }
+ public R visitClassType(ClassType t, S s) { return visitType(t, s); }
+ public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
+ public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
+ public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
+ public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
+ public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
+ public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
+ public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
+ public R visitForAll(ForAll t, S s) { return visitType(t, s); }
+ public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
+ public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
+ }
+
+ /**
+ * A default visitor for symbols. All visitor methods except
+ * visitSymbol are implemented by delegating to visitSymbol. Concrete
+ * subclasses must provide an implementation of visitSymbol and can
+ * override other methods as needed.
+ *
+ * @param <R> the return type of the operation implemented by this
+ * visitor; use Void if no return type is needed.
+ * @param <S> the type of the second argument (the first being the
+ * symbol itself) of the operation implemented by this visitor; use
+ * Void if a second argument is not needed.
+ */
+ public static abstract class DefaultSymbolVisitor<R,S> implements Symbol.Visitor<R,S> {
+ final public R visit(Symbol s, S arg) { return s.accept(this, arg); }
+ public R visitClassSymbol(ClassSymbol s, S arg) { return visitSymbol(s, arg); }
+ public R visitMethodSymbol(MethodSymbol s, S arg) { return visitSymbol(s, arg); }
+ public R visitOperatorSymbol(OperatorSymbol s, S arg) { return visitSymbol(s, arg); }
+ public R visitPackageSymbol(PackageSymbol s, S arg) { return visitSymbol(s, arg); }
+ public R visitTypeSymbol(TypeSymbol s, S arg) { return visitSymbol(s, arg); }
+ public R visitVarSymbol(VarSymbol s, S arg) { return visitSymbol(s, arg); }
+ }
+
+ /**
+ * A <em>simple</em> visitor for types. This visitor is simple as
+ * captured wildcards, for-all types (generic methods), and
+ * undetermined type variables (part of inference) are hidden.
+ * Captured wildcards are hidden by treating them as type
+ * variables and the rest are hidden by visiting their qtypes.
+ *
+ * @param <R> the return type of the operation implemented by this
+ * visitor; use Void if no return type is needed.
+ * @param <S> the type of the second argument (the first being the
+ * type itself) of the operation implemented by this visitor; use
+ * Void if a second argument is not needed.
+ */
+ public static abstract class SimpleVisitor<R,S> extends DefaultTypeVisitor<R,S> {
+ @Override
+ public R visitCapturedType(CapturedType t, S s) {
+ return visitTypeVar(t, s);
+ }
+ @Override
+ public R visitForAll(ForAll t, S s) {
+ return visit(t.qtype, s);
+ }
+ @Override
+ public R visitUndetVar(UndetVar t, S s) {
+ return visit(t.qtype, s);
+ }
+ }
+
+ /**
+ * A plain relation on types. That is a 2-ary function on the
+ * form Type × Type → Boolean.
+ * <!-- In plain text: Type x Type -> Boolean -->
+ */
+ public static abstract class TypeRelation extends SimpleVisitor<Boolean,Type> {}
+
+ /**
+ * A convenience visitor for implementing operations that only
+ * require one argument (the type itself), that is, unary
+ * operations.
+ *
+ * @param <R> the return type of the operation implemented by this
+ * visitor; use Void if no return type is needed.
+ */
+ public static abstract class UnaryVisitor<R> extends SimpleVisitor<R,Void> {
+ final public R visit(Type t) { return t.accept(this, null); }
+ }
+
+ /**
+ * A visitor for implementing a mapping from types to types. The
+ * default behavior of this class is to implement the identity
+ * mapping (mapping a type to itself). This can be overridden in
+ * subclasses.
+ *
+ * @param <S> the type of the second argument (the first being the
+ * type itself) of this mapping; use Void if a second argument is
+ * not needed.
+ */
+ public static class MapVisitor<S> extends DefaultTypeVisitor<Type,S> {
+ final public Type visit(Type t) { return t.accept(this, null); }
+ public Type visitType(Type t, S s) { return t; }
+ }
+
+ /**
+ * An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
+ * This class implements the functional interface {@code Function}, that allows it to be used
+ * fluently in stream-like processing.
+ */
+ public static class TypeMapping<S> extends MapVisitor<S> implements Function<Type, Type> {
+ @Override
+ public Type apply(Type type) { return visit(type); }
+
+ List<Type> visit(List<Type> ts, S s) {
+ return ts.map(t -> visit(t, s));
+ }
+
+ @Override
+ public Type visitCapturedType(CapturedType t, S s) {
+ return visitTypeVar(t, s);
+ }
+ }
+ // </editor-fold>
+
+
+ // <editor-fold defaultstate="collapsed" desc="Annotation support">
+
+ public RetentionPolicy getRetention(Attribute.Compound a) {
+ return getRetention(a.type.tsym);
+ }
+
+ public RetentionPolicy getRetention(TypeSymbol sym) {
+ RetentionPolicy vis = RetentionPolicy.CLASS; // the default
+ Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
+ if (c != null) {
+ Attribute value = c.member(names.value);
+ if (value != null && value instanceof Attribute.Enum) {
+ Name levelName = ((Attribute.Enum)value).value.name;
+ if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
+ else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
+ else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
+ else ;// /* fail soft */ throw new AssertionError(levelName);
+ }
+ }
+ return vis;
+ }
+ // </editor-fold>
+
+ // <editor-fold defaultstate="collapsed" desc="Signature Generation">
+
+ public static abstract class SignatureGenerator {
+
+ private final Types types;
+
+ protected abstract void append(char ch);
+ protected abstract void append(byte[] ba);
+ protected abstract void append(Name name);
+ protected void classReference(ClassSymbol c) { /* by default: no-op */ }
+
+ protected SignatureGenerator(Types types) {
+ this.types = types;
+ }
+
+ /**
+ * Assemble signature of given type in string buffer.
+ */
+ public void assembleSig(Type type) {
+ switch (type.getTag()) {
+ case BYTE:
+ append('B');
+ break;
+ case SHORT:
+ append('S');
+ break;
+ case CHAR:
+ append('C');
+ break;
+ case INT:
+ append('I');
+ break;
+ case LONG:
+ append('J');
+ break;
+ case FLOAT:
+ append('F');
+ break;
+ case DOUBLE:
+ append('D');
+ break;
+ case BOOLEAN:
+ append('Z');
+ break;
+ case VOID:
+ append('V');
+ break;
+ case CLASS:
+ append('L');
+ assembleClassSig(type);
+ append(';');
+ break;
+ case ARRAY:
+ ArrayType at = (ArrayType) type;
+ append('[');
+ assembleSig(at.elemtype);
+ break;
+ case METHOD:
+ MethodType mt = (MethodType) type;
+ append('(');
+ assembleSig(mt.argtypes);
+ append(')');
+ assembleSig(mt.restype);
+ if (hasTypeVar(mt.thrown)) {
+ for (List<Type> l = mt.thrown; l.nonEmpty(); l = l.tail) {
+ append('^');
+ assembleSig(l.head);
+ }
+ }
+ break;
+ case WILDCARD: {
+ Type.WildcardType ta = (Type.WildcardType) type;
+ switch (ta.kind) {
+ case SUPER:
+ append('-');
+ assembleSig(ta.type);
+ break;
+ case EXTENDS:
+ append('+');
+ assembleSig(ta.type);
+ break;
+ case UNBOUND:
+ append('*');
+ break;
+ default:
+ throw new AssertionError(ta.kind);
+ }
+ break;
+ }
+ case TYPEVAR:
+ append('T');
+ append(type.tsym.name);
+ append(';');
+ break;
+ case FORALL:
+ Type.ForAll ft = (Type.ForAll) type;
+ assembleParamsSig(ft.tvars);
+ assembleSig(ft.qtype);
+ break;
+ default:
+ throw new AssertionError("typeSig " + type.getTag());
+ }
+ }
+
+ public boolean hasTypeVar(List<Type> l) {
+ while (l.nonEmpty()) {
+ if (l.head.hasTag(TypeTag.TYPEVAR)) {
+ return true;
+ }
+ l = l.tail;
+ }
+ return false;
+ }
+
+ public void assembleClassSig(Type type) {
+ ClassType ct = (ClassType) type;
+ ClassSymbol c = (ClassSymbol) ct.tsym;
+ classReference(c);
+ Type outer = ct.getEnclosingType();
+ if (outer.allparams().nonEmpty()) {
+ boolean rawOuter =
+ c.owner.kind == MTH || // either a local class
+ c.name == types.names.empty; // or anonymous
+ assembleClassSig(rawOuter
+ ? types.erasure(outer)
+ : outer);
+ append(rawOuter ? '$' : '.');
+ Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
+ append(rawOuter
+ ? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength())
+ : c.name);
+ } else {
+ append(externalize(c.flatname));
+ }
+ if (ct.getTypeArguments().nonEmpty()) {
+ append('<');
+ assembleSig(ct.getTypeArguments());
+ append('>');
+ }
+ }
+
+ public void assembleParamsSig(List<Type> typarams) {
+ append('<');
+ for (List<Type> ts = typarams; ts.nonEmpty(); ts = ts.tail) {
+ Type.TypeVar tvar = (Type.TypeVar) ts.head;
+ append(tvar.tsym.name);
+ List<Type> bounds = types.getBounds(tvar);
+ if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
+ append(':');
+ }
+ for (List<Type> l = bounds; l.nonEmpty(); l = l.tail) {
+ append(':');
+ assembleSig(l.head);
+ }
+ }
+ append('>');
+ }
+
+ private void assembleSig(List<Type> types) {
+ for (List<Type> ts = types; ts.nonEmpty(); ts = ts.tail) {
+ assembleSig(ts.head);
+ }
+ }
+ }
+ // </editor-fold>
+
+ public void newRound() {
+ descCache._map.clear();
+ isDerivedRawCache.clear();
+ implCache._map.clear();
+ membersCache._map.clear();
+ closureCache.clear();
+ }
+}