/*
* Copyright (c) 2003, 2014, 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.Set;
import java.util.WeakHashMap;
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.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.jvm.ClassReader;
import com.sun.tools.javac.tree.JCTree;
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.MTH;
import static com.sun.tools.javac.code.Scope.*;
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;
/**
* 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<Types>();
final Symtab syms;
final JavacMessages messages;
final Names names;
final boolean allowBoxing;
final boolean allowCovariantReturns;
final boolean allowObjectToPrimitiveCast;
final boolean allowDefaultMethods;
final ClassReader reader;
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);
allowBoxing = source.allowBoxing();
allowCovariantReturns = source.allowCovariantReturns();
allowObjectToPrimitiveCast = source.allowObjectToPrimitiveCast();
allowDefaultMethods = source.allowDefaultMethods();
reader = ClassReader.instance(context);
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.unannotatedType();
if (w.isSuperBound())
return w.bound == null ? syms.objectType : w.bound.bound;
else
return wildUpperBound(w.type);
}
else return t.unannotatedType();
}
/**
* 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.unannotatedType();
return v.isCaptured() ? cvarUpperBound(v.bound) : v;
}
else return t.unannotatedType();
}
/**
* 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.unannotatedType();
return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type);
}
else return t.unannotatedType();
}
/**
* 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 v = (TypeVar) t.unannotatedType();
return v.isCaptured() ? cvarLowerBound(v.getLowerBound()) : v;
}
else return t.unannotatedType();
}
// </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.unannotatedType());
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<Type>();
ListBuffer<Type> to = new ListBuffer<Type>();
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<Type>();
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<Type>();
for (List<Type> iter = opens; iter.nonEmpty(); iter = iter.tail) {
qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND, syms.boundClass, (TypeVar) iter.head.unannotatedType()));
}
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);
}
if (!allowBoxing) return false;
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<TypeSymbol, Entry>();
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("no.suitable.functional.intf.inst", 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.getElements(new DescriptorFilter(origin))) {
Type mtype = memberType(origin.type, sym);
if (abstracts.isEmpty() ||
(sym.name == abstracts.first().name &&
overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
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("incompatible.abstracts", 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("no.abstracts", 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.MultilineDiagnostic incompatibleDescriptors =
new JCDiagnostic.MultilineDiagnostic(diags.fragment("incompatible.descs.in.functional.intf",
Kinds.kindName(origin), origin), 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) {
//pick argument types - simply take the signature that is a
//subsignature of all other signatures in the list (as per JLS 8.4.2)
List<Symbol> mostSpecific = List.nil();
outer: for (Symbol msym1 : methodSyms) {
Type mt1 = memberType(origin.type, msym1);
for (Symbol msym2 : methodSyms) {
Type mt2 = memberType(origin.type, msym2);
if (!isSubSignature(mt1, mt2)) {
continue outer;
}
}
mostSpecific = mostSpecific.prepend(msym1);
}
if (mostSpecific.isEmpty()) {
return null;
}
//pick return types - this is done in two phases: (i) first, the most
//specific return type is chosen using strict subtyping; if this fails,
//a second attempt is made using return type substitutability (see JLS 8.4.5)
boolean phase2 = false;
Symbol bestSoFar = null;
while (bestSoFar == null) {
outer: for (Symbol msym1 : mostSpecific) {
Type mt1 = memberType(origin.type, msym1);
for (Symbol msym2 : methodSyms) {
Type mt2 = memberType(origin.type, msym2);
if (phase2 ?
!returnTypeSubstitutable(mt1, mt2) :
!isSubtypeInternal(mt1.getReturnType(), mt2.getReturnType())) {
continue outer;
}
}
bestSoFar = msym1;
}
if (phase2) {
break;
} else {
phase2 = true;
}
}
if (bestSoFar == null) return null;
//merge thrown types - form the intersection of all the thrown types in
//all the signatures in the list
boolean toErase = !bestSoFar.type.hasTag(FORALL);
List<Type> thrown = null;
Type mt1 = memberType(origin.type, bestSoFar);
for (Symbol msym2 : methodSyms) {
Type mt2 = memberType(origin.type, msym2);
List<Type> thrown_mt2 = mt2.getThrownTypes();
if (toErase) {
thrown_mt2 = erasure(thrown_mt2);
} else {
/* If bestSoFar is generic then all the methods are generic.
* The opposite is not true: a non generic method can override
* a generic method (raw override) so it's safe to cast mt1 and
* mt2 to ForAll.
*/
ForAll fa1 = (ForAll)mt1;
ForAll fa2 = (ForAll)mt2;
thrown_mt2 = subst(thrown_mt2, fa2.tvars, fa1.tvars);
}
thrown = (thrown == null) ?
thrown_mt2 :
chk.intersect(thrown_mt2, thrown);
}
final List<Type> thrown1 = thrown;
return new FunctionDescriptor(bestSoFar) {
@Override
public Type getType(Type origin) {
Type mt = memberType(origin, getSymbol());
return createMethodTypeWithThrown(mt, thrown1);
}
};
}
boolean isSubtypeInternal(Type s, Type t) {
return (s.isPrimitive() && t.isPrimitive()) ?
isSameType(t, s) :
isSubtype(s, t);
}
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) {
Type capturedSite = capture(site);
if (capturedSite != site) {
Type formalInterface = site.tsym.type;
ListBuffer<Type> typeargs = new ListBuffer<>();
List<Type> actualTypeargs = site.getTypeArguments();
List<Type> capturedTypeargs = capturedSite.getTypeArguments();
//simply replace the wildcards with its bound
for (Type t : formalInterface.getTypeArguments()) {
if (actualTypeargs.head.hasTag(WILDCARD)) {
WildcardType wt = (WildcardType)actualTypeargs.head.unannotatedType();
Type bound;
switch (wt.kind) {
case EXTENDS:
case UNBOUND:
CapturedType capVar = (CapturedType)capturedTypeargs.head.unannotatedType();
//use declared bound if it doesn't depend on formal type-args
bound = capVar.bound.containsAny(capturedSite.getTypeArguments()) ?
wt.type : capVar.bound;
break;
default:
bound = wt.type;
}
typeargs.append(bound);
} else {
typeargs.append(actualTypeargs.head);
}
actualTypeargs = actualTypeargs.tail;
capturedTypeargs = capturedTypeargs.tail;
}
return subst(formalInterface, formalInterface.getTypeArguments(), typeargs.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 = null;
csym.members_field = new Scope(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.<Type>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.getElementsByName(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 == Kinds.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 == Kinds.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, warn);
if (result) {
checkUnsafeVarargsConversion(t, s, warn);
}
return result;
}
//where
private boolean isSubtypeUncheckedInternal(Type t, Type s, Warner warn) {
if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
t = t.unannotatedType();
s = s.unannotatedType();
if (((ArrayType)t).elemtype.isPrimitive()) {
return isSameType(elemtype(t), elemtype(s));
} else {
return isSubtypeUnchecked(elemtype(t), elemtype(s), warn);
}
} else if (isSubtype(t, s)) {
return true;
} else if (t.hasTag(TYPEVAR)) {
return isSubtypeUnchecked(t.getUpperBound(), s, 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;
}
t = t.unannotatedType();
s = s.unannotatedType();
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 == s)
return true;
t = t.unannotatedType();
s = s.unannotatedType();
if (t == 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 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)
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<TypePair>();
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);
changed = true;
} else if (s != orig) {
s = new WildcardType(wildUpperBound(s),
BoundKind.EXTENDS,
syms.boundClass);
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 SE 7, 8.4.1) is a method that
* (i) is declared in the java.lang.invoke.MethodHandle class, (ii) takes
* a single variable arity parameter (iii) whose declared type is Object[],
* (iv) has a return type of Object 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 &&
argtypes.length() == 1 &&
argtypes.head.hasTag(TypeTag.ARRAY) &&
msym.type.getReturnType().tsym == syms.objectType.tsym &&
((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);
}
public boolean isSameAnnotatedType(Type t, Type s) {
return isSameAnnotatedType.visit(t, s);
}
// where
abstract class SameTypeVisitor extends TypeRelation {
public Boolean visitType(Type t, Type s) {
if (t == 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.unannotatedType(), (TypeVar)s.unannotatedType());
}
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.isPartial())
return visit(s, t);
else
return false;
}
@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;
HashSet<UniqueType> set = new HashSet<UniqueType>();
for (Type x : interfaces(t))
set.add(new UniqueType(x.unannotatedType(), Types.this));
for (Type x : interfaces(s)) {
if (!set.remove(new UniqueType(x.unannotatedType(), Types.this)))
return false;
}
return (set.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.unannotatedType();
return t.kind == t2.kind &&
isSameType(t.type, t2.type, true);
}
}
};
/**
* A version of LooseSameTypeVisitor that takes AnnotatedTypes
* into account.
*/
TypeRelation isSameAnnotatedType = new LooseSameTypeVisitor() {
@Override
public Boolean visitAnnotatedType(AnnotatedType t, Type s) {
if (!s.isAnnotated())
return false;
if (!t.getAnnotationMirrors().containsAll(s.getAnnotationMirrors()))
return false;
if (!s.getAnnotationMirrors().containsAll(t.getAnnotationMirrors()))
return false;
return visit(t.unannotatedType(), s);
}
};
// </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.unannotatedType();
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)
|| t.type == s
|| isCaptureOf(s, t)
|| ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), cvarLowerBound(wildLowerBound(s)))) &&
// TODO: JDK-8039214, cvarUpperBound call here is incorrect
(t.isSuperBound() || isSubtypeNoCapture(cvarUpperBound(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.unannotatedType()).isCaptured())
return false;
return isSameWildcard(t, ((CapturedType)s.unannotatedType()).wildcard);
}
public boolean isSameWildcard(WildcardType t, Type s) {
if (!s.hasTag(WILDCARD))
return false;
WildcardType w = (WildcardType)s.unannotatedType();
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>
/**
* Can t and s be compared for equality? Any primitive ==
* primitive or primitive == object comparisons here are an error.
* Unboxing and correct primitive == primitive comparisons are
* already dealt with in Attr.visitBinary.
*
*/
public boolean isEqualityComparable(Type s, Type t, Warner warn) {
if (t.isNumeric() && s.isNumeric())
return true;
boolean tPrimitive = t.isPrimitive();
boolean sPrimitive = s.isPrimitive();
if (!tPrimitive && !sPrimitive) {
return isCastable(s, t, warn) || isCastable(t, s, warn);
} else {
return false;
}
}
// <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())
return allowBoxing && (
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.isIntersection() || s.isIntersection()) {
return !t.isIntersection() ?
visitIntersectionType((IntersectionClassType)s.unannotatedType(), t, true) :
visitIntersectionType((IntersectionClassType)t.unannotatedType(), 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 visitIntersectionType(IntersectionClassType ict, Type s, boolean reverse) {
Warner warn = noWarnings;
for (Type c : ict.getComponents()) {
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<TypePair>();
@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 map(ts, cvarLowerBoundMapping);
}
private final Mapping cvarLowerBoundMapping = new Mapping("cvarLowerBound") {
public Type apply(Type t) {
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) {
if (t.hasTag(TYPEVAR)) {
while (t.hasTag(TYPEVAR))
t = t.getUpperBound();
t = rewriteQuantifiers(t, true, true);
}
return 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:
t = t.unannotatedType();
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 Mapping elemTypeFun = new Mapping ("elemTypeFun") {
public Type apply(Type t) {
while (t.hasTag(TYPEVAR)) {
t = t.getUpperBound();
}
return elemtype(t);
}
};
/**
* 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.
*
* @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:
if (Byte.MIN_VALUE <= value && value <= Byte.MAX_VALUE)
return true;
break;
case CHAR:
if (Character.MIN_VALUE <= value && value <= Character.MAX_VALUE)
return true;
break;
case SHORT:
if (Short.MIN_VALUE <= value && value <= Short.MAX_VALUE)
return true;
break;
case INT:
return true;
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
return erasure.visit(t, recurse);
}
// where
private SimpleVisitor<Type, Boolean> erasure = new SimpleVisitor<Type, Boolean>() {
public Type visitType(Type t, Boolean recurse) {
if (t.isPrimitive())
return t; /*fast special case*/
else
return t.map(recurse ? erasureRecFun : erasureFun);
}
@Override
public Type visitWildcardType(WildcardType t, Boolean recurse) {
return erasure(wildUpperBound(t), recurse);
}
@Override
public Type visitClassType(ClassType t, Boolean recurse) {
Type erased = t.tsym.erasure(Types.this);
if (recurse) {
erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym);
}
return erased;
}
@Override
public Type visitTypeVar(TypeVar t, Boolean recurse) {
return erasure(t.bound, recurse);
}
@Override
public Type visitErrorType(ErrorType t, Boolean recurse) {
return t;
}
@Override
public Type visitAnnotatedType(AnnotatedType t, Boolean recurse) {
Type erased = erasure(t.unannotatedType(), recurse);
if (erased.isAnnotated()) {
// This can only happen when the underlying type is a
// type variable and the upper bound of it is annotated.
// The annotation on the type variable overrides the one
// on the bound.
erased = ((AnnotatedType)erased).unannotatedType();
}
return erased.annotatedType(t.getAnnotationMirrors());
}
};
private Mapping erasureFun = new Mapping ("erasure") {
public Type apply(Type t) { return erasure(t); }
};
private Mapping erasureRecFun = new Mapping ("erasureRecursive") {
public Type apply(Type t) { return erasureRecursive(t); }
};
public List<Type> erasure(List<Type> ts) {
return Type.map(ts, erasureFun);
}
public Type erasureRecursive(Type t) {
return erasure(t, true);
}
public List<Type> erasureRecursive(List<Type> ts) {
return Type.map(ts, erasureRecFun);
}
// </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 = new Scope(bc);
return intersectionType;
}
/**
* A convenience wrapper for {@link #makeIntersectionType(List)}; the
* arguments are converted to a list and passed to the other
* method. Note that this might cause a symbol completion.
* Hence, this version of makeIntersectionType may not be called
* during a classfile read.
*/
public Type makeIntersectionType(Type bound1, Type bound2) {
return makeIntersectionType(List.of(bound1, bound2));
}
// </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 visitIntersectionType((IntersectionClassType) type);
}
}
private List<Type> visitIntersectionType(final IntersectionClassType it) {
return it.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<Type,Boolean>();
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);
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 (Scope.Entry e = syms.objectType.tsym.members().lookup(msym.name) ; e.scope != null ; e = e.next()) {
if (msym.overrides(e.sym, origin, Types.this, true)) {
return true;
}
}
return false;
}
// <editor-fold defaultstate="collapsed" desc="Determining method implementation in given site">
class ImplementationCache {
private WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>> _map =
new WeakHashMap<MethodSymbol, SoftReference<Map<TypeSymbol, Entry>>>();
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<TypeSymbol, Entry>();
_map.put(ms, new SoftReference<Map<TypeSymbol, Entry>>(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)) {
while (t.hasTag(TYPEVAR))
t = t.getUpperBound();
TypeSymbol c = t.tsym;
for (Scope.Entry e = c.members().lookup(ms.name, implFilter);
e.scope != null;
e = e.next(implFilter)) {
if (e.sym != null &&
e.sym.overrides(ms, origin, Types.this, checkResult))
return (MethodSymbol)e.sym;
}
}
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(final Filter<Symbol> sf) {
return new Filter<Symbol>() {
@Override
public boolean accepts(Symbol s) {
return !s.owner.isInterface() && (sf == null || sf.accepts(s));
}
};
}
@Override
public Iterable<Symbol> getElements(Filter<Symbol> sf) {
return scope.getElements(combine(sf));
}
@Override
public Iterable<Symbol> getElementsByName(Name name, Filter<Symbol> sf) {
return scope.getElementsByName(name, combine(sf));
}
@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.addSubScope(visit(i, null));
}
membersClosure.addSubScope(visit(supertype(t), null));
membersClosure.addSubScope(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);
if (cs == null)
Assert.error("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 (Scope.Entry e = s.elems;
undef == null && e != null;
e = e.sibling) {
if (e.sym.kind == MTH &&
(e.sym.flags() & (ABSTRACT|IPROXY|DEFAULT)) == ABSTRACT) {
MethodSymbol absmeth = (MethodSymbol)e.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;
}
}
}
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;
}
//where
public List<MethodSymbol> interfaceCandidates(Type site, MethodSymbol ms) {
Filter<Symbol> filter = new MethodFilter(ms, site);
List<MethodSymbol> candidates = List.nil();
for (Symbol s : membersClosure(site, false).getElements(filter)) {
if (!site.tsym.isInterface() && !s.owner.isInterface()) {
return List.of((MethodSymbol)s);
} else if (!candidates.contains(s)) {
candidates = candidates.prepend((MethodSymbol)s);
}
}
return prune(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 == Kinds.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 new Subst(from, to).subst(ts);
}
/**
* 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 new Subst(from, to).subst(t);
}
private class Subst extends UnaryVisitor<Type> {
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;
}
Type subst(Type t) {
if (from.tail == null)
return t;
else
return visit(t);
}
List<Type> subst(List<Type> ts) {
if (from.tail == null)
return ts;
boolean wild = false;
if (ts.nonEmpty() && from.nonEmpty()) {
Type head1 = subst(ts.head);
List<Type> tail1 = subst(ts.tail);
if (head1 != ts.head || tail1 != ts.tail)
return tail1.prepend(head1);
}
return ts;
}
public Type visitType(Type t, Void ignored) {
return t;
}
@Override
public Type visitMethodType(MethodType t, Void ignored) {
List<Type> argtypes = subst(t.argtypes);
Type restype = subst(t.restype);
List<Type> thrown = subst(t.thrown);
if (argtypes == t.argtypes &&
restype == t.restype &&
thrown == t.thrown)
return t;
else
return new MethodType(argtypes, restype, thrown, t.tsym);
}
@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 == from.head) {
return to.head.withTypeVar(t);
}
}
return t;
}
@Override
public Type visitUndetVar(UndetVar t, Void ignored) {
//do nothing - we should not replace inside undet variables
return t;
}
@Override
public Type visitClassType(ClassType t, Void ignored) {
if (!t.isCompound()) {
List<Type> typarams = t.getTypeArguments();
List<Type> typarams1 = subst(typarams);
Type outer = t.getEnclosingType();
Type outer1 = subst(outer);
if (typarams1 == typarams && outer1 == outer)
return t;
else
return new ClassType(outer1, typarams1, t.tsym);
} else {
Type st = subst(supertype(t));
List<Type> is = subst(interfaces(t));
if (st == supertype(t) && is == interfaces(t))
return t;
else
return makeIntersectionType(is.prepend(st));
}
}
@Override
public Type visitWildcardType(WildcardType t, Void ignored) {
Type bound = t.type;
if (t.kind != BoundKind.UNBOUND)
bound = subst(bound);
if (bound == t.type) {
return t;
} else {
if (t.isExtendsBound() && bound.isExtendsBound())
bound = wildUpperBound(bound);
return new WildcardType(bound, t.kind, syms.boundClass, t.bound);
}
}
@Override
public Type visitArrayType(ArrayType t, Void ignored) {
Type elemtype = subst(t.elemtype);
if (elemtype == t.elemtype)
return t;
else
return new ArrayType(elemtype, t.tsym);
}
@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 = subst(t.qtype);
if (tvars1 == t.tvars && qtype1 == t.qtype) {
return t;
} else if (tvars1 == t.tvars) {
return new ForAll(tvars1, qtype1);
} else {
return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1));
}
}
@Override
public Type visitErrorType(ErrorType t, Void ignored) {
return t;
}
}
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));
}
// 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);
// the new bound should use the new type variable in place
// of the old
tv.bound = subst(bound1, List.<Type>of(t), List.<Type>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 = Type.map(tvars, 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 Mapping newInstanceFun = new Mapping("newInstanceFun") {
public Type apply(Type t) { return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound()); }
};
// </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);
}
public Type visitForAll(ForAll t, Type newReturn) {
return new ForAll(t.tvars, t.qtype.accept(this, newReturn));
}
};
// <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) {
t = t.unannotatedType();
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.unannotatedType()), 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<Type,List<Type>>();
/**
* 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;
}
/**
* Insert a type in a closure
*/
public List<Type> insert(List<Type> cl, Type t) {
if (cl.isEmpty()) {
return cl.prepend(t);
} else if (t.tsym == cl.head.tsym) {
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).prepend(cl.head);
}
}
/**
* Form the union of two closures
*/
public List<Type> union(List<Type> cl1, List<Type> cl2) {
if (cl1.isEmpty()) {
return cl2;
} else if (cl2.isEmpty()) {
return cl1;
} else if (cl1.head.tsym == cl2.head.tsym) {
return union(cl1.tail, cl2.tail).prepend(cl1.head);
} else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
return union(cl1.tail, cl2).prepend(cl1.head);
} else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
return union(cl1, cl2.tail).prepend(cl2.head);
} else {
// unrelated types
return union(cl1.tail, cl2).prepend(cl1.head);
}
}
/**
* 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<TypePair>();
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<Type>();
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());
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.<Type>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> lowers = List.nil();
for (Type bound : bounds) {
if (!bound.isInterface()) {
classCount++;
Type lower = cvarLowerBound(bound);
if (bound != lower && !lower.hasTag(BOT))
lowers = insert(lowers, lower);
}
}
if (classCount > 1) {
if (lowers.isEmpty())
return createErrorType(errT);
else
return glbFlattened(union(bounds, lowers), errT);
}
}
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.visit(t);
}
// where
private static final UnaryVisitor<Integer> hashCode = new 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.tsym);
}
@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 (!allowCovariantReturns)
return false;
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) ||
allowCovariantReturns &&
!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 reader.enterClass(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) {
if (allowBoxing) {
for (int i=0; i<syms.boxedName.length; i++) {
Name box = syms.boxedName[i];
if (box != null &&
asSuper(t, reader.enterClass(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());
}
}
t = t.unannotatedType();
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.unannotatedType();
Type Ui = currentA.head.getUpperBound();
CapturedType Si = (CapturedType)currentS.head.unannotatedType();
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);
else
return t;
}
// where
public List<Type> freshTypeVariables(List<Type> types) {
ListBuffer<Type> result = new ListBuffer<>();
for (Type t : types) {
if (t.hasTag(WILDCARD)) {
t = t.unannotatedType();
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);
if (!allowCovariantReturns)
// reject if there is a common method signature with
// incompatible return types.
chk.checkCompatibleAbstracts(warn.pos(), from, to);
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 (!allowCovariantReturns)
// reject if there is a common method signature with
// incompatible return types.
chk.checkCompatibleAbstracts(warn.pos(), from, to);
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() ?
((IntersectionClassType)to.unannotatedType()).getComponents() : 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<Symbol,Type>();
}
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<TypePair>();
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<Type>();
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.unannotatedType();
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.isSameAnnotatedType(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 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); }
// Pretend annotations don't exist
public R visitAnnotatedType(AnnotatedType t, S s) { return visit(t.unannotatedType(), 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; }
}
// </editor-fold>
// <editor-fold defaultstate="collapsed" desc="Annotation support">
public RetentionPolicy getRetention(Attribute.Compound a) {
return getRetention(a.type.tsym);
}
public RetentionPolicy getRetention(Symbol 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) {
type = type.unannotatedType();
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) {
type = type.unannotatedType();
ClassType ct = (ClassType) type;
ClassSymbol c = (ClassSymbol) ct.tsym;
classReference(c);
Type outer = ct.getEnclosingType();
if (outer.allparams().nonEmpty()) {
boolean rawOuter =
c.owner.kind == Kinds.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>
}