/*
* Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package com.sun.tools.javac.code;
import java.lang.ref.SoftReference;
import java.util.HashSet;
import java.util.HashMap;
import java.util.Locale;
import java.util.Map;
import java.util.Optional;
import java.util.Set;
import java.util.WeakHashMap;
import java.util.function.BiPredicate;
import java.util.function.Function;
import java.util.stream.Collector;
import javax.tools.JavaFileObject;
import com.sun.tools.javac.code.Attribute.RetentionPolicy;
import com.sun.tools.javac.code.Lint.LintCategory;
import com.sun.tools.javac.code.Source.Feature;
import com.sun.tools.javac.code.Type.UndetVar.InferenceBound;
import com.sun.tools.javac.code.TypeMetadata.Entry.Kind;
import com.sun.tools.javac.comp.AttrContext;
import com.sun.tools.javac.comp.Check;
import com.sun.tools.javac.comp.Enter;
import com.sun.tools.javac.comp.Env;
import com.sun.tools.javac.util.*;
import static com.sun.tools.javac.code.BoundKind.*;
import static com.sun.tools.javac.code.Flags.*;
import static com.sun.tools.javac.code.Kinds.Kind.*;
import static com.sun.tools.javac.code.Scope.*;
import static com.sun.tools.javac.code.Scope.LookupKind.NON_RECURSIVE;
import static com.sun.tools.javac.code.Symbol.*;
import static com.sun.tools.javac.code.Type.*;
import static com.sun.tools.javac.code.TypeTag.*;
import static com.sun.tools.javac.jvm.ClassFile.externalize;
import com.sun.tools.javac.resources.CompilerProperties.Fragments;
/**
* Utility class containing various operations on types.
*
* Unless other names are more illustrative, the following naming
* conventions should be observed in this file:
*
*
* - t
* - If the first argument to an operation is a type, it should be named t.
* - s
* - Similarly, if the second argument to an operation is a type, it should be named s.
* - ts
* - If an operations takes a list of types, the first should be named ts.
* - ss
* - A second list of types should be named ss.
*
*
* This is NOT part of any supported API.
* If you write code that depends on this, you do so at your own risk.
* This code and its internal interfaces are subject to change or
* deletion without notice.
*/
public class Types {
protected static final Context.Key typesKey = new Context.Key<>();
final Symtab syms;
final JavacMessages messages;
final Names names;
final boolean allowDefaultMethods;
final boolean mapCapturesToBounds;
final Check chk;
final Enter enter;
JCDiagnostic.Factory diags;
List warnStack = List.nil();
final Name capturedName;
public final Warner noWarnings;
//
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);
allowDefaultMethods = Feature.DEFAULT_METHODS.allowedInSource(source);
mapCapturesToBounds = Feature.MAP_CAPTURES_TO_BOUNDS.allowedInSource(source);
chk = Check.instance(context);
enter = Enter.instance(context);
capturedName = names.fromString("");
messages = JavacMessages.instance(context);
diags = JCDiagnostic.Factory.instance(context);
noWarnings = new Warner(null);
}
//
//
/**
* Get a wildcard's upper bound, returning non-wildcards unchanged.
* @param t a type argument, either a wildcard or a type
*/
public Type wildUpperBound(Type t) {
if (t.hasTag(WILDCARD)) {
WildcardType w = (WildcardType) t;
if (w.isSuperBound())
return w.bound == null ? syms.objectType : w.bound.bound;
else
return wildUpperBound(w.type);
}
else return t;
}
/**
* Get a capture variable's upper bound, returning other types unchanged.
* @param t a type
*/
public Type cvarUpperBound(Type t) {
if (t.hasTag(TYPEVAR)) {
TypeVar v = (TypeVar) t;
return v.isCaptured() ? cvarUpperBound(v.bound) : v;
}
else return t;
}
/**
* Get a wildcard's lower bound, returning non-wildcards unchanged.
* @param t a type argument, either a wildcard or a type
*/
public Type wildLowerBound(Type t) {
if (t.hasTag(WILDCARD)) {
WildcardType w = (WildcardType) t;
return w.isExtendsBound() ? syms.botType : wildLowerBound(w.type);
}
else return t;
}
/**
* Get a capture variable's lower bound, returning other types unchanged.
* @param t a type
*/
public Type cvarLowerBound(Type t) {
if (t.hasTag(TYPEVAR) && ((TypeVar) t).isCaptured()) {
return cvarLowerBound(t.getLowerBound());
}
else return t;
}
/**
* Recursively skip type-variables until a class/array type is found; capture conversion is then
* (optionally) applied to the resulting type. This is useful for i.e. computing a site that is
* suitable for a method lookup.
*/
public Type skipTypeVars(Type site, boolean capture) {
while (site.hasTag(TYPEVAR)) {
site = site.getUpperBound();
}
return capture ? capture(site) : site;
}
//
//
/**
* A projection kind. See {@link TypeProjection}
*/
enum ProjectionKind {
UPWARDS() {
@Override
ProjectionKind complement() {
return DOWNWARDS;
}
},
DOWNWARDS() {
@Override
ProjectionKind complement() {
return UPWARDS;
}
};
abstract ProjectionKind complement();
}
/**
* This visitor performs upwards and downwards projections on types.
*
* A projection is defined as a function that takes a type T, a set of type variables V and that
* produces another type S.
*
* An upwards projection maps a type T into a type S such that (i) T has no variables in V,
* and (ii) S is an upper bound of T.
*
* A downwards projection maps a type T into a type S such that (i) T has no variables in V,
* and (ii) S is a lower bound of T.
*
* Note that projections are only allowed to touch variables in V. Theferore it is possible for
* a projection to leave its input type unchanged if it does not contain any variables in V.
*
* Moreover, note that while an upwards projection is always defined (every type as an upper bound),
* a downwards projection is not always defined.
*
* Examples:
*
* {@code upwards(List<#CAP1>, [#CAP1]) = List, where #CAP1 <: String }
* {@code downwards(List<#CAP2>, [#CAP2]) = List, where #CAP2 :> String }
* {@code upwards(List<#CAP1>, [#CAP2]) = List<#CAP1> }
* {@code downwards(List<#CAP1>, [#CAP1]) = not defined }
*/
class TypeProjection extends TypeMapping {
List vars;
Set seen = new HashSet<>();
public TypeProjection(List vars) {
this.vars = vars;
}
@Override
public Type visitClassType(ClassType t, ProjectionKind pkind) {
if (t.isCompound()) {
List components = directSupertypes(t);
List components1 = components.map(c -> c.map(this, pkind));
if (components == components1) return t;
else return makeIntersectionType(components1);
} else {
Type outer = t.getEnclosingType();
Type outer1 = visit(outer, pkind);
List typarams = t.getTypeArguments();
List formals = t.tsym.type.getTypeArguments();
ListBuffer typarams1 = new ListBuffer<>();
boolean changed = false;
for (Type actual : typarams) {
Type t2 = mapTypeArgument(t, formals.head.getUpperBound(), actual, pkind);
if (t2.hasTag(BOT)) {
//not defined
return syms.botType;
}
typarams1.add(t2);
changed |= actual != t2;
formals = formals.tail;
}
if (outer1 == outer && !changed) return t;
else return new ClassType(outer1, typarams1.toList(), t.tsym, t.getMetadata()) {
@Override
protected boolean needsStripping() {
return true;
}
};
}
}
@Override
public Type visitArrayType(ArrayType t, ProjectionKind s) {
Type elemtype = t.elemtype;
Type elemtype1 = visit(elemtype, s);
if (elemtype1 == elemtype) {
return t;
} else if (elemtype1.hasTag(BOT)) {
//undefined
return syms.botType;
} else {
return new ArrayType(elemtype1, t.tsym, t.metadata) {
@Override
protected boolean needsStripping() {
return true;
}
};
}
}
@Override
public Type visitTypeVar(TypeVar t, ProjectionKind pkind) {
if (vars.contains(t)) {
if (seen.add(t)) {
try {
final Type bound;
switch (pkind) {
case UPWARDS:
bound = t.getUpperBound();
break;
case DOWNWARDS:
bound = (t.getLowerBound() == null) ?
syms.botType :
t.getLowerBound();
break;
default:
Assert.error();
return null;
}
return bound.map(this, pkind);
} finally {
seen.remove(t);
}
} else {
//cycle
return pkind == ProjectionKind.UPWARDS ?
syms.objectType : syms.botType;
}
} else {
return t;
}
}
private Type mapTypeArgument(Type site, Type declaredBound, Type t, ProjectionKind pkind) {
return t.containsAny(vars) ?
t.map(new TypeArgumentProjection(site, declaredBound), pkind) :
t;
}
class TypeArgumentProjection extends TypeMapping {
Type site;
Type declaredBound;
TypeArgumentProjection(Type site, Type declaredBound) {
this.site = site;
this.declaredBound = declaredBound;
}
@Override
public Type visitType(Type t, ProjectionKind pkind) {
//type argument is some type containing restricted vars
if (pkind == ProjectionKind.DOWNWARDS) {
//not defined
return syms.botType;
}
Type upper = t.map(TypeProjection.this, ProjectionKind.UPWARDS);
Type lower = t.map(TypeProjection.this, ProjectionKind.DOWNWARDS);
List formals = site.tsym.type.getTypeArguments();
BoundKind bk;
Type bound;
if (!isSameType(upper, syms.objectType) &&
(declaredBound.containsAny(formals) ||
!isSubtype(declaredBound, upper))) {
bound = upper;
bk = EXTENDS;
} else if (!lower.hasTag(BOT)) {
bound = lower;
bk = SUPER;
} else {
bound = syms.objectType;
bk = UNBOUND;
}
return makeWildcard(bound, bk);
}
@Override
public Type visitWildcardType(WildcardType wt, ProjectionKind pkind) {
//type argument is some wildcard whose bound contains restricted vars
Type bound = syms.botType;
BoundKind bk = wt.kind;
switch (wt.kind) {
case EXTENDS:
bound = wt.type.map(TypeProjection.this, pkind);
if (bound.hasTag(BOT)) {
return syms.botType;
}
break;
case SUPER:
bound = wt.type.map(TypeProjection.this, pkind.complement());
if (bound.hasTag(BOT)) {
bound = syms.objectType;
bk = UNBOUND;
}
break;
}
return makeWildcard(bound, bk);
}
private Type makeWildcard(Type bound, BoundKind bk) {
return new WildcardType(bound, bk, syms.boundClass) {
@Override
protected boolean needsStripping() {
return true;
}
};
}
}
}
/**
* Computes an upward projection of given type, and vars. See {@link TypeProjection}.
*
* @param t the type to be projected
* @param vars the set of type variables to be mapped
* @return the type obtained as result of the projection
*/
public Type upward(Type t, List vars) {
return t.map(new TypeProjection(vars), ProjectionKind.UPWARDS);
}
/**
* Computes the set of captured variables mentioned in a given type. See {@link CaptureScanner}.
* This routine is typically used to computed the input set of variables to be used during
* an upwards projection (see {@link Types#upward(Type, List)}).
*
* @param t the type where occurrences of captured variables have to be found
* @return the set of captured variables found in t
*/
public List captures(Type t) {
CaptureScanner cs = new CaptureScanner();
Set captures = new HashSet<>();
cs.visit(t, captures);
return List.from(captures);
}
/**
* This visitor scans a type recursively looking for occurrences of captured type variables.
*/
class CaptureScanner extends SimpleVisitor> {
@Override
public Void visitType(Type t, Set types) {
return null;
}
@Override
public Void visitClassType(ClassType t, Set seen) {
if (t.isCompound()) {
directSupertypes(t).forEach(s -> visit(s, seen));
} else {
t.allparams().forEach(ta -> visit(ta, seen));
}
return null;
}
@Override
public Void visitArrayType(ArrayType t, Set seen) {
return visit(t.elemtype, seen);
}
@Override
public Void visitWildcardType(WildcardType t, Set seen) {
visit(t.type, seen);
return null;
}
@Override
public Void visitTypeVar(TypeVar t, Set seen) {
if ((t.tsym.flags() & Flags.SYNTHETIC) != 0 && seen.add(t)) {
visit(t.getUpperBound(), seen);
}
return null;
}
@Override
public Void visitCapturedType(CapturedType t, Set seen) {
if (seen.add(t)) {
visit(t.getUpperBound(), seen);
visit(t.getLowerBound(), seen);
}
return null;
}
}
//
//
/**
* 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 isUnbounded = new UnaryVisitor() {
public Boolean visitType(Type t, Void ignored) {
return true;
}
@Override
public Boolean visitClassType(ClassType t, Void ignored) {
List parms = t.tsym.type.allparams();
List args = t.allparams();
while (parms.nonEmpty()) {
WildcardType unb = new WildcardType(syms.objectType,
BoundKind.UNBOUND,
syms.boundClass,
(TypeVar)parms.head);
if (!containsType(args.head, unb))
return false;
parms = parms.tail;
args = args.tail;
}
return true;
}
};
//
//
/**
* 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:
*
* If there is exactly one parameterized instance of sym that is a
* subtype of t, that parameterized instance is returned.
* 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 asSub = new SimpleVisitor() {
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 from = new ListBuffer<>();
ListBuffer to = new ListBuffer<>();
try {
adapt(base, t, from, to);
} catch (AdaptFailure ex) {
return null;
}
Type res = subst(sym.type, from.toList(), to.toList());
if (!isSubtype(res, t))
return null;
ListBuffer openVars = new ListBuffer<>();
for (List 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 opens = openVars.toList();
ListBuffer qs = new ListBuffer<>();
for (List iter = opens; iter.nonEmpty(); iter = iter.tail) {
qs.append(new WildcardType(syms.objectType, BoundKind.UNBOUND,
syms.boundClass, (TypeVar) iter.head));
}
res = subst(res, opens, qs.toList());
}
}
return res;
}
@Override
public Type visitErrorType(ErrorType t, Symbol sym) {
return t;
}
};
//
//
/**
* Is t a subtype of or convertible via boxing/unboxing
* conversion to s?
*/
public boolean isConvertible(Type t, Type s, Warner warn) {
if (t.hasTag(ERROR)) {
return true;
}
boolean tPrimitive = t.isPrimitive();
boolean sPrimitive = s.isPrimitive();
if (tPrimitive == sPrimitive) {
return isSubtypeUnchecked(t, s, warn);
}
boolean tUndet = t.hasTag(UNDETVAR);
boolean sUndet = s.hasTag(UNDETVAR);
if (tUndet || sUndet) {
return tUndet ?
isSubtype(t, boxedTypeOrType(s)) :
isSubtype(boxedTypeOrType(t), s);
}
return tPrimitive
? isSubtype(boxedClass(t).type, s)
: isSubtype(unboxedType(t), s);
}
/**
* Is t a subtype of or convertible via boxing/unboxing
* conversions to s?
*/
public boolean isConvertible(Type t, Type s) {
return isConvertible(t, s, noWarnings);
}
//
//
/**
* 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 _map = new WeakHashMap<>();
class FunctionDescriptor {
Symbol descSym;
FunctionDescriptor(Symbol descSym) {
this.descSym = descSym;
}
public Symbol getSymbol() {
return descSym;
}
public Type getType(Type site) {
site = removeWildcards(site);
if (site.isIntersection()) {
IntersectionClassType ict = (IntersectionClassType)site;
for (Type component : ict.getExplicitComponents()) {
if (!chk.checkValidGenericType(component)) {
//if the inferred functional interface type is not well-formed,
//or if it's not a subtype of the original target, issue an error
throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
}
}
} else {
if (!chk.checkValidGenericType(site)) {
//if the inferred functional interface type is not well-formed,
//or if it's not a subtype of the original target, issue an error
throw failure(diags.fragment(Fragments.NoSuitableFunctionalIntfInst(site)));
}
}
return memberType(site, descSym);
}
}
class Entry {
final FunctionDescriptor cachedDescRes;
final int prevMark;
public Entry(FunctionDescriptor cachedDescRes,
int prevMark) {
this.cachedDescRes = cachedDescRes;
this.prevMark = prevMark;
}
boolean matches(int mark) {
return this.prevMark == mark;
}
}
FunctionDescriptor get(TypeSymbol origin) throws FunctionDescriptorLookupError {
Entry e = _map.get(origin);
CompoundScope members = membersClosure(origin.type, false);
if (e == null ||
!e.matches(members.getMark())) {
FunctionDescriptor descRes = findDescriptorInternal(origin, members);
_map.put(origin, new Entry(descRes, members.getMark()));
return descRes;
}
else {
return e.cachedDescRes;
}
}
/**
* Compute the function descriptor associated with a given functional interface
*/
public FunctionDescriptor findDescriptorInternal(TypeSymbol origin,
CompoundScope membersCache) throws FunctionDescriptorLookupError {
if (!origin.isInterface() || (origin.flags() & ANNOTATION) != 0) {
//t must be an interface
throw failure("not.a.functional.intf", origin);
}
final ListBuffer abstracts = new ListBuffer<>();
for (Symbol sym : membersCache.getSymbols(new DescriptorFilter(origin))) {
Type mtype = memberType(origin.type, sym);
if (abstracts.isEmpty()) {
abstracts.append(sym);
} else if ((sym.name == abstracts.first().name &&
overrideEquivalent(mtype, memberType(origin.type, abstracts.first())))) {
if (!abstracts.stream().filter(msym -> msym.owner.isSubClass(sym.enclClass(), Types.this))
.map(msym -> memberType(origin.type, msym))
.anyMatch(abstractMType -> isSubSignature(abstractMType, mtype))) {
abstracts.append(sym);
}
} else {
//the target method(s) should be the only abstract members of t
throw failure("not.a.functional.intf.1", origin,
diags.fragment(Fragments.IncompatibleAbstracts(Kinds.kindName(origin), origin)));
}
}
if (abstracts.isEmpty()) {
//t must define a suitable non-generic method
throw failure("not.a.functional.intf.1", origin,
diags.fragment(Fragments.NoAbstracts(Kinds.kindName(origin), origin)));
} else if (abstracts.size() == 1) {
return new FunctionDescriptor(abstracts.first());
} else { // size > 1
FunctionDescriptor descRes = mergeDescriptors(origin, abstracts.toList());
if (descRes == null) {
//we can get here if the functional interface is ill-formed
ListBuffer descriptors = new ListBuffer<>();
for (Symbol desc : abstracts) {
String key = desc.type.getThrownTypes().nonEmpty() ?
"descriptor.throws" : "descriptor";
descriptors.append(diags.fragment(key, desc.name,
desc.type.getParameterTypes(),
desc.type.getReturnType(),
desc.type.getThrownTypes()));
}
JCDiagnostic msg =
diags.fragment(Fragments.IncompatibleDescsInFunctionalIntf(Kinds.kindName(origin),
origin));
JCDiagnostic.MultilineDiagnostic incompatibleDescriptors =
new JCDiagnostic.MultilineDiagnostic(msg, descriptors.toList());
throw failure(incompatibleDescriptors);
}
return descRes;
}
}
/**
* Compute a synthetic type for the target descriptor given a list
* of override-equivalent methods in the functional interface type.
* The resulting method type is a method type that is override-equivalent
* and return-type substitutable with each method in the original list.
*/
private FunctionDescriptor mergeDescriptors(TypeSymbol origin, List methodSyms) {
return mergeAbstracts(methodSyms, origin.type, false)
.map(bestSoFar -> new FunctionDescriptor(bestSoFar.baseSymbol()) {
@Override
public Type getType(Type origin) {
Type mt = memberType(origin, getSymbol());
return createMethodTypeWithThrown(mt, bestSoFar.type.getThrownTypes());
}
}).orElse(null);
}
FunctionDescriptorLookupError failure(String msg, Object... args) {
return failure(diags.fragment(msg, args));
}
FunctionDescriptorLookupError failure(JCDiagnostic diag) {
return new FunctionDescriptorLookupError().setMessage(diag);
}
}
private DescriptorCache descCache = new DescriptorCache();
/**
* Find the method descriptor associated to this class symbol - if the
* symbol 'origin' is not a functional interface, an exception is thrown.
*/
public Symbol findDescriptorSymbol(TypeSymbol origin) throws FunctionDescriptorLookupError {
return descCache.get(origin).getSymbol();
}
/**
* Find the type of the method descriptor associated to this class symbol -
* if the symbol 'origin' is not a functional interface, an exception is thrown.
*/
public Type findDescriptorType(Type origin) throws FunctionDescriptorLookupError {
return descCache.get(origin.tsym).getType(origin);
}
/**
* Is given type a functional interface?
*/
public boolean isFunctionalInterface(TypeSymbol tsym) {
try {
findDescriptorSymbol(tsym);
return true;
} catch (FunctionDescriptorLookupError ex) {
return false;
}
}
public boolean isFunctionalInterface(Type site) {
try {
findDescriptorType(site);
return true;
} catch (FunctionDescriptorLookupError ex) {
return false;
}
}
public Type removeWildcards(Type site) {
if (site.getTypeArguments().stream().anyMatch(t -> t.hasTag(WILDCARD))) {
//compute non-wildcard parameterization - JLS 9.9
List actuals = site.getTypeArguments();
List formals = site.tsym.type.getTypeArguments();
ListBuffer targs = new ListBuffer<>();
for (Type formal : formals) {
Type actual = actuals.head;
Type bound = formal.getUpperBound();
if (actuals.head.hasTag(WILDCARD)) {
WildcardType wt = (WildcardType)actual;
//check that bound does not contain other formals
if (bound.containsAny(formals)) {
targs.add(wt.type);
} else {
//compute new type-argument based on declared bound and wildcard bound
switch (wt.kind) {
case UNBOUND:
targs.add(bound);
break;
case EXTENDS:
targs.add(glb(bound, wt.type));
break;
case SUPER:
targs.add(wt.type);
break;
default:
Assert.error("Cannot get here!");
}
}
} else {
//not a wildcard - the new type argument remains unchanged
targs.add(actual);
}
actuals = actuals.tail;
}
return subst(site.tsym.type, formals, targs.toList());
} else {
return site;
}
}
/**
* Create a symbol for a class that implements a given functional interface
* and overrides its functional descriptor. This routine is used for two
* main purposes: (i) checking well-formedness of a functional interface;
* (ii) perform functional interface bridge calculation.
*/
public ClassSymbol makeFunctionalInterfaceClass(Env env, Name name, Type target, long cflags) {
if (target == null || target == syms.unknownType) {
return null;
}
Symbol descSym = findDescriptorSymbol(target.tsym);
Type descType = findDescriptorType(target);
ClassSymbol csym = new ClassSymbol(cflags, name, env.enclClass.sym.outermostClass());
csym.completer = Completer.NULL_COMPLETER;
csym.members_field = WriteableScope.create(csym);
MethodSymbol instDescSym = new MethodSymbol(descSym.flags(), descSym.name, descType, csym);
csym.members_field.enter(instDescSym);
Type.ClassType ctype = new Type.ClassType(Type.noType, List.nil(), csym);
ctype.supertype_field = syms.objectType;
ctype.interfaces_field = target.isIntersection() ?
directSupertypes(target) :
List.of(target);
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 functionalInterfaceBridges(TypeSymbol origin) {
Assert.check(isFunctionalInterface(origin));
Symbol descSym = findDescriptorSymbol(origin);
CompoundScope members = membersClosure(origin.type, false);
ListBuffer overridden = new ListBuffer<>();
outer: for (Symbol m2 : members.getSymbolsByName(descSym.name, bridgeFilter)) {
if (m2 == descSym) continue;
else if (descSym.overrides(m2, origin, Types.this, false)) {
for (Symbol m3 : overridden) {
if (isSameType(m3.erasure(Types.this), m2.erasure(Types.this)) ||
(m3.overrides(m2, origin, Types.this, false) &&
(pendingBridges((ClassSymbol)origin, m3.enclClass()) ||
(((MethodSymbol)m2).binaryImplementation((ClassSymbol)m3.owner, Types.this) != null)))) {
continue outer;
}
}
overridden.add(m2);
}
}
return overridden.toList();
}
//where
private Filter bridgeFilter = new Filter() {
public boolean accepts(Symbol t) {
return t.kind == MTH &&
t.name != names.init &&
t.name != names.clinit &&
(t.flags() & SYNTHETIC) == 0;
}
};
private boolean pendingBridges(ClassSymbol origin, TypeSymbol s) {
//a symbol will be completed from a classfile if (a) symbol has
//an associated file object with CLASS kind and (b) the symbol has
//not been entered
if (origin.classfile != null &&
origin.classfile.getKind() == JavaFileObject.Kind.CLASS &&
enter.getEnv(origin) == null) {
return false;
}
if (origin == s) {
return true;
}
for (Type t : interfaces(origin.type)) {
if (pendingBridges((ClassSymbol)t.tsym, s)) {
return true;
}
}
return false;
}
//
/**
* 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 {
TypeSymbol origin;
DescriptorFilter(TypeSymbol origin) {
this.origin = origin;
}
@Override
public boolean accepts(Symbol sym) {
return sym.kind == MTH &&
(sym.flags() & (ABSTRACT | DEFAULT)) == ABSTRACT &&
!overridesObjectMethod(origin, sym) &&
(interfaceCandidates(origin.type, (MethodSymbol)sym).head.flags() & DEFAULT) == 0;
}
}
//
/**
* Is t an unchecked subtype of s?
*/
public boolean isSubtypeUnchecked(Type t, Type s) {
return isSubtypeUnchecked(t, s, noWarnings);
}
/**
* Is t an unchecked subtype of s?
*/
public boolean isSubtypeUnchecked(Type t, Type s, Warner warn) {
boolean result = isSubtypeUncheckedInternal(t, s, true, warn);
if (result) {
checkUnsafeVarargsConversion(t, s, warn);
}
return result;
}
//where
private boolean isSubtypeUncheckedInternal(Type t, Type s, boolean capture, Warner warn) {
if (t.hasTag(ARRAY) && s.hasTag(ARRAY)) {
if (((ArrayType)t).elemtype.isPrimitive()) {
return isSameType(elemtype(t), elemtype(s));
} else {
return isSubtypeUncheckedInternal(elemtype(t), elemtype(s), false, warn);
}
} else if (isSubtype(t, s, capture)) {
return true;
} else if (t.hasTag(TYPEVAR)) {
return isSubtypeUncheckedInternal(t.getUpperBound(), s, false, warn);
} else if (!s.isRaw()) {
Type t2 = asSuper(t, s.tsym);
if (t2 != null && t2.isRaw()) {
if (isReifiable(s)) {
warn.silentWarn(LintCategory.UNCHECKED);
} else {
warn.warn(LintCategory.UNCHECKED);
}
return true;
}
}
return false;
}
private void checkUnsafeVarargsConversion(Type t, Type s, Warner warn) {
if (!t.hasTag(ARRAY) || isReifiable(t)) {
return;
}
ArrayType from = (ArrayType)t;
boolean shouldWarn = false;
switch (s.getTag()) {
case ARRAY:
ArrayType to = (ArrayType)s;
shouldWarn = from.isVarargs() &&
!to.isVarargs() &&
!isReifiable(from);
break;
case CLASS:
shouldWarn = from.isVarargs();
break;
}
if (shouldWarn) {
warn.warn(LintCategory.VARARGS);
}
}
/**
* Is t a subtype of s?
* (not defined for Method and ForAll types)
*/
final public boolean isSubtype(Type t, Type s) {
return isSubtype(t, s, true);
}
final public boolean isSubtypeNoCapture(Type t, Type s) {
return isSubtype(t, s, false);
}
public boolean isSubtype(Type t, Type s, boolean capture) {
if (t.equalsIgnoreMetadata(s))
return true;
if (s.isPartial())
return isSuperType(s, t);
if (s.isCompound()) {
for (Type s2 : interfaces(s).prepend(supertype(s))) {
if (!isSubtype(t, s2, capture))
return false;
}
return true;
}
// Generally, if 's' is a lower-bounded type variable, recur on lower bound; but
// for inference variables and intersections, we need to keep 's'
// (see JLS 4.10.2 for intersections and 18.2.3 for inference vars)
if (!t.hasTag(UNDETVAR) && !t.isCompound()) {
// TODO: JDK-8039198, bounds checking sometimes passes in a wildcard as s
Type lower = cvarLowerBound(wildLowerBound(s));
if (s != lower && !lower.hasTag(BOT))
return isSubtype(capture ? capture(t) : t, lower, false);
}
return isSubtype.visit(capture ? capture(t) : t, s);
}
// where
private TypeRelation isSubtype = new TypeRelation()
{
@Override
public Boolean visitType(Type t, Type s) {
switch (t.getTag()) {
case BYTE:
return (!s.hasTag(CHAR) && t.getTag().isSubRangeOf(s.getTag()));
case CHAR:
return (!s.hasTag(SHORT) && t.getTag().isSubRangeOf(s.getTag()));
case SHORT: case INT: case LONG:
case FLOAT: case DOUBLE:
return t.getTag().isSubRangeOf(s.getTag());
case BOOLEAN: case VOID:
return t.hasTag(s.getTag());
case TYPEVAR:
return isSubtypeNoCapture(t.getUpperBound(), s);
case BOT:
return
s.hasTag(BOT) || s.hasTag(CLASS) ||
s.hasTag(ARRAY) || s.hasTag(TYPEVAR);
case WILDCARD: //we shouldn't be here - avoids crash (see 7034495)
case NONE:
return false;
default:
throw new AssertionError("isSubtype " + t.getTag());
}
}
private Set cache = new HashSet<>();
private boolean containsTypeRecursive(Type t, Type s) {
TypePair pair = new TypePair(t, s);
if (cache.add(pair)) {
try {
return containsType(t.getTypeArguments(),
s.getTypeArguments());
} finally {
cache.remove(pair);
}
} else {
return containsType(t.getTypeArguments(),
rewriteSupers(s).getTypeArguments());
}
}
private Type rewriteSupers(Type t) {
if (!t.isParameterized())
return t;
ListBuffer from = new ListBuffer<>();
ListBuffer to = new ListBuffer<>();
adaptSelf(t, from, to);
if (from.isEmpty())
return t;
ListBuffer rewrite = new ListBuffer<>();
boolean changed = false;
for (Type orig : to.toList()) {
Type s = rewriteSupers(orig);
if (s.isSuperBound() && !s.isExtendsBound()) {
s = new WildcardType(syms.objectType,
BoundKind.UNBOUND,
syms.boundClass,
s.getMetadata());
changed = true;
} else if (s != orig) {
s = new WildcardType(wildUpperBound(s),
BoundKind.EXTENDS,
syms.boundClass,
s.getMetadata());
changed = true;
}
rewrite.append(s);
}
if (changed)
return subst(t.tsym.type, from.toList(), rewrite.toList());
else
return t;
}
@Override
public Boolean visitClassType(ClassType t, Type s) {
Type sup = asSuper(t, s.tsym);
if (sup == null) return false;
// If t is an intersection, sup might not be a class type
if (!sup.hasTag(CLASS)) return isSubtypeNoCapture(sup, s);
return sup.tsym == s.tsym
// Check type variable containment
&& (!s.isParameterized() || containsTypeRecursive(s, sup))
&& isSubtypeNoCapture(sup.getEnclosingType(),
s.getEnclosingType());
}
@Override
public Boolean visitArrayType(ArrayType t, Type s) {
if (s.hasTag(ARRAY)) {
if (t.elemtype.isPrimitive())
return isSameType(t.elemtype, elemtype(s));
else
return isSubtypeNoCapture(t.elemtype, elemtype(s));
}
if (s.hasTag(CLASS)) {
Name sname = s.tsym.getQualifiedName();
return sname == names.java_lang_Object
|| sname == names.java_lang_Cloneable
|| sname == names.java_io_Serializable;
}
return false;
}
@Override
public Boolean visitUndetVar(UndetVar t, Type s) {
//todo: test against origin needed? or replace with substitution?
if (t == s || t.qtype == s || s.hasTag(ERROR) || s.hasTag(UNKNOWN)) {
return true;
} else if (s.hasTag(BOT)) {
//if 's' is 'null' there's no instantiated type U for which
//U <: s (but 'null' itself, which is not a valid type)
return false;
}
t.addBound(InferenceBound.UPPER, s, Types.this);
return true;
}
@Override
public Boolean visitErrorType(ErrorType t, Type s) {
return true;
}
};
/**
* Is t a subtype of every type in given list `ts'?
* (not defined for Method and ForAll types)
* Allows unchecked conversions.
*/
public boolean isSubtypeUnchecked(Type t, List ts, Warner warn) {
for (List 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 ts, List 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 ts, List 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();*/
}
//
//
/**
* 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);
}
}
//
//
/**
* Are corresponding elements of the lists the same type? If
* lists are of different length, return false.
*/
public boolean isSameTypes(List ts, List ss) {
while (ts.tail != null && ss.tail != null
/*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
isSameType(ts.head, ss.head)) {
ts = ts.tail;
ss = ss.tail;
}
return ts.tail == null && ss.tail == null;
/*inlined: ts.isEmpty() && ss.isEmpty();*/
}
/**
* A polymorphic signature method (JLS 15.12.3) is a method that
* (i) is declared in the java.lang.invoke.MethodHandle/VarHandle classes;
* (ii) takes a single variable arity parameter;
* (iii) whose declared type is Object[];
* (iv) has any return type, Object signifying a polymorphic return type; and
* (v) is native.
*/
public boolean isSignaturePolymorphic(MethodSymbol msym) {
List argtypes = msym.type.getParameterTypes();
return (msym.flags_field & NATIVE) != 0 &&
(msym.owner == syms.methodHandleType.tsym || msym.owner == syms.varHandleType.tsym) &&
argtypes.length() == 1 &&
argtypes.head.hasTag(TypeTag.ARRAY) &&
((ArrayType)argtypes.head).elemtype.tsym == syms.objectType.tsym;
}
/**
* Is t the same type as s?
*/
public boolean isSameType(Type t, Type s) {
return isSameTypeVisitor.visit(t, s);
}
// where
/**
* Type-equality relation - type variables are considered
* equals if they share the same object identity.
*/
TypeRelation isSameTypeVisitor = new TypeRelation() {
public Boolean visitType(Type t, Type s) {
if (t.equalsIgnoreMetadata(s))
return true;
if (s.isPartial())
return visit(s, t);
switch (t.getTag()) {
case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
case DOUBLE: case BOOLEAN: case VOID: case BOT: case NONE:
return t.hasTag(s.getTag());
case TYPEVAR: {
if (s.hasTag(TYPEVAR)) {
//type-substitution does not preserve type-var types
//check that type var symbols and bounds are indeed the same
return t == s;
}
else {
//special case for s == ? super X, where upper(s) = u
//check that u == t, where u has been set by Type.withTypeVar
return s.isSuperBound() &&
!s.isExtendsBound() &&
visit(t, wildUpperBound(s));
}
}
default:
throw new AssertionError("isSameType " + t.getTag());
}
}
@Override
public Boolean visitWildcardType(WildcardType t, Type s) {
if (!s.hasTag(WILDCARD)) {
return false;
} else {
WildcardType t2 = (WildcardType)s;
return (t.kind == t2.kind || (t.isExtendsBound() && s.isExtendsBound())) &&
isSameType(t.type, t2.type);
}
}
@Override
public Boolean visitClassType(ClassType t, Type s) {
if (t == s)
return true;
if (s.isPartial())
return visit(s, t);
if (s.isSuperBound() && !s.isExtendsBound())
return visit(t, wildUpperBound(s)) && visit(t, wildLowerBound(s));
if (t.isCompound() && s.isCompound()) {
if (!visit(supertype(t), supertype(s)))
return false;
Map tMap = new HashMap<>();
for (Type ti : interfaces(t)) {
if (tMap.containsKey(ti)) {
throw new AssertionError("Malformed intersection");
}
tMap.put(ti.tsym, ti);
}
for (Type si : interfaces(s)) {
if (!tMap.containsKey(si.tsym))
return false;
Type ti = tMap.remove(si.tsym);
if (!visit(ti, si))
return false;
}
return tMap.isEmpty();
}
return t.tsym == s.tsym
&& visit(t.getEnclosingType(), s.getEnclosingType())
&& containsTypeEquivalent(t.getTypeArguments(), s.getTypeArguments());
}
@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;
}
};
//
//
public boolean containedBy(Type t, Type s) {
switch (t.getTag()) {
case UNDETVAR:
if (s.hasTag(WILDCARD)) {
UndetVar undetvar = (UndetVar)t;
WildcardType wt = (WildcardType)s;
switch(wt.kind) {
case UNBOUND:
break;
case EXTENDS: {
Type bound = wildUpperBound(s);
undetvar.addBound(InferenceBound.UPPER, bound, this);
break;
}
case SUPER: {
Type bound = wildLowerBound(s);
undetvar.addBound(InferenceBound.LOWER, bound, this);
break;
}
}
return true;
} else {
return isSameType(t, s);
}
case ERROR:
return true;
default:
return containsType(s, t);
}
}
boolean containsType(List ts, List 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.
*
* T contains S if:
*
*
{@code L(T) <: L(S) && U(S) <: U(T)}
*
*
This relation is only used by ClassType.isSubtype(), that
* is,
*
*
{@code C <: C if T contains S.}
*
* 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:
*
*
{@code U(S) <: U(T) if T is "super" bound (U(T) *is* the bound)}
*
*
{@code L(T) <: L(S) if T is "extends" bound (L(T) is bottom)}
*
* @param t a type
* @param s a type
*/
public boolean containsType(Type t, Type s) {
return containsType.visit(t, s);
}
// where
private TypeRelation containsType = new TypeRelation() {
public Boolean visitType(Type t, Type s) {
if (s.isPartial())
return containedBy(s, t);
else
return isSameType(t, s);
}
// void debugContainsType(WildcardType t, Type s) {
// System.err.println();
// System.err.format(" does %s contain %s?%n", t, s);
// System.err.format(" %s U(%s) <: U(%s) %s = %s%n",
// wildUpperBound(s), s, t, wildUpperBound(t),
// t.isSuperBound()
// || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t)));
// System.err.format(" %s L(%s) <: L(%s) %s = %s%n",
// wildLowerBound(t), t, s, wildLowerBound(s),
// t.isExtendsBound()
// || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s)));
// System.err.println();
// }
@Override
public Boolean visitWildcardType(WildcardType t, Type s) {
if (s.isPartial())
return containedBy(s, t);
else {
// debugContainsType(t, s);
return isSameWildcard(t, s)
|| isCaptureOf(s, t)
|| ((t.isExtendsBound() || isSubtypeNoCapture(wildLowerBound(t), wildLowerBound(s))) &&
(t.isSuperBound() || isSubtypeNoCapture(wildUpperBound(s), wildUpperBound(t))));
}
}
@Override
public Boolean visitUndetVar(UndetVar t, Type s) {
if (!s.hasTag(WILDCARD)) {
return isSameType(t, s);
} else {
return false;
}
}
@Override
public Boolean visitErrorType(ErrorType t, Type s) {
return true;
}
};
public boolean isCaptureOf(Type s, WildcardType t) {
if (!s.hasTag(TYPEVAR) || !((TypeVar)s).isCaptured())
return false;
return isSameWildcard(t, ((CapturedType)s).wildcard);
}
public boolean isSameWildcard(WildcardType t, Type s) {
if (!s.hasTag(WILDCARD))
return false;
WildcardType w = (WildcardType)s;
return w.kind == t.kind && w.type == t.type;
}
public boolean containsTypeEquivalent(List ts, List ss) {
while (ts.nonEmpty() && ss.nonEmpty()
&& containsTypeEquivalent(ts.head, ss.head)) {
ts = ts.tail;
ss = ss.tail;
}
return ts.isEmpty() && ss.isEmpty();
}
//
//
public boolean isCastable(Type t, Type s) {
return isCastable(t, s, noWarnings);
}
/**
* Is t is castable to s?
* s is assumed to be an erased type.
* (not defined for Method and ForAll types).
*/
public boolean isCastable(Type t, Type s, Warner warn) {
if (t == s)
return true;
if (t.isPrimitive() != s.isPrimitive()) {
t = skipTypeVars(t, false);
return (isConvertible(t, s, warn)
|| (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) || t.hasTag(NONE))
return true;
switch (t.getTag()) {
case BYTE: case CHAR: case SHORT: case INT: case LONG: case FLOAT:
case DOUBLE:
return s.isNumeric();
case BOOLEAN:
return s.hasTag(BOOLEAN);
case VOID:
return false;
case BOT:
return isSubtype(t, s);
default:
throw new AssertionError();
}
}
@Override
public Boolean visitWildcardType(WildcardType t, Type s) {
return isCastable(wildUpperBound(t), s, warnStack.head);
}
@Override
public Boolean visitClassType(ClassType t, Type s) {
if (s.hasTag(ERROR) || s.hasTag(BOT))
return true;
if (s.hasTag(TYPEVAR)) {
if (isCastable(t, s.getUpperBound(), noWarnings)) {
warnStack.head.warn(LintCategory.UNCHECKED);
return true;
} else {
return false;
}
}
if (t.isCompound() || s.isCompound()) {
return !t.isCompound() ?
visitCompoundType((ClassType)s, t, true) :
visitCompoundType(t, s, false);
}
if (s.hasTag(CLASS) || s.hasTag(ARRAY)) {
boolean upcast;
if ((upcast = isSubtype(erasure(t), erasure(s)))
|| isSubtype(erasure(s), erasure(t))) {
if (!upcast && s.hasTag(ARRAY)) {
if (!isReifiable(s))
warnStack.head.warn(LintCategory.UNCHECKED);
return true;
} else if (s.isRaw()) {
return true;
} else if (t.isRaw()) {
if (!isUnbounded(s))
warnStack.head.warn(LintCategory.UNCHECKED);
return true;
}
// Assume |a| <: |b|
final Type a = upcast ? t : s;
final Type b = upcast ? s : t;
final boolean HIGH = true;
final boolean LOW = false;
final boolean DONT_REWRITE_TYPEVARS = false;
Type aHigh = rewriteQuantifiers(a, HIGH, DONT_REWRITE_TYPEVARS);
Type aLow = rewriteQuantifiers(a, LOW, DONT_REWRITE_TYPEVARS);
Type bHigh = rewriteQuantifiers(b, HIGH, DONT_REWRITE_TYPEVARS);
Type bLow = rewriteQuantifiers(b, LOW, DONT_REWRITE_TYPEVARS);
Type lowSub = asSub(bLow, aLow.tsym);
Type highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
if (highSub == null) {
final boolean REWRITE_TYPEVARS = true;
aHigh = rewriteQuantifiers(a, HIGH, REWRITE_TYPEVARS);
aLow = rewriteQuantifiers(a, LOW, REWRITE_TYPEVARS);
bHigh = rewriteQuantifiers(b, HIGH, REWRITE_TYPEVARS);
bLow = rewriteQuantifiers(b, LOW, REWRITE_TYPEVARS);
lowSub = asSub(bLow, aLow.tsym);
highSub = (lowSub == null) ? null : asSub(bHigh, aHigh.tsym);
}
if (highSub != null) {
if (!(a.tsym == highSub.tsym && a.tsym == lowSub.tsym)) {
Assert.error(a.tsym + " != " + highSub.tsym + " != " + lowSub.tsym);
}
if (!disjointTypes(aHigh.allparams(), highSub.allparams())
&& !disjointTypes(aHigh.allparams(), lowSub.allparams())
&& !disjointTypes(aLow.allparams(), highSub.allparams())
&& !disjointTypes(aLow.allparams(), lowSub.allparams())) {
if (upcast ? giveWarning(a, b) :
giveWarning(b, a))
warnStack.head.warn(LintCategory.UNCHECKED);
return true;
}
}
if (isReifiable(s))
return isSubtypeUnchecked(a, b);
else
return isSubtypeUnchecked(a, b, warnStack.head);
}
// Sidecast
if (s.hasTag(CLASS)) {
if ((s.tsym.flags() & INTERFACE) != 0) {
return ((t.tsym.flags() & FINAL) == 0)
? sideCast(t, s, warnStack.head)
: sideCastFinal(t, s, warnStack.head);
} else if ((t.tsym.flags() & INTERFACE) != 0) {
return ((s.tsym.flags() & FINAL) == 0)
? sideCast(t, s, warnStack.head)
: sideCastFinal(t, s, warnStack.head);
} else {
// unrelated class types
return false;
}
}
}
return false;
}
boolean visitCompoundType(ClassType ct, Type s, boolean reverse) {
Warner warn = noWarnings;
for (Type c : directSupertypes(ct)) {
warn.clear();
if (reverse ? !isCastable(s, c, warn) : !isCastable(c, s, warn))
return false;
}
if (warn.hasLint(LintCategory.UNCHECKED))
warnStack.head.warn(LintCategory.UNCHECKED);
return true;
}
@Override
public Boolean visitArrayType(ArrayType t, Type s) {
switch (s.getTag()) {
case ERROR:
case BOT:
return true;
case TYPEVAR:
if (isCastable(s, t, noWarnings)) {
warnStack.head.warn(LintCategory.UNCHECKED);
return true;
} else {
return false;
}
case CLASS:
return isSubtype(t, s);
case ARRAY:
if (elemtype(t).isPrimitive() || elemtype(s).isPrimitive()) {
return elemtype(t).hasTag(elemtype(s).getTag());
} else {
return visit(elemtype(t), elemtype(s));
}
default:
return false;
}
}
@Override
public Boolean visitTypeVar(TypeVar t, Type s) {
switch (s.getTag()) {
case ERROR:
case BOT:
return true;
case TYPEVAR:
if (isSubtype(t, s)) {
return true;
} else if (isCastable(t.bound, s, noWarnings)) {
warnStack.head.warn(LintCategory.UNCHECKED);
return true;
} else {
return false;
}
default:
return isCastable(t.bound, s, warnStack.head);
}
}
@Override
public Boolean visitErrorType(ErrorType t, Type s) {
return true;
}
};
//
//
public boolean disjointTypes(List ts, List 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} is castable to {@code C} 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 cache = new HashSet<>();
@Override
public Boolean visitType(Type t, Type s) {
if (s.hasTag(WILDCARD))
return visit(s, t);
else
return notSoftSubtypeRecursive(t, s) || notSoftSubtypeRecursive(s, t);
}
private boolean isCastableRecursive(Type t, Type s) {
TypePair pair = new TypePair(t, s);
if (cache.add(pair)) {
try {
return Types.this.isCastable(t, s);
} finally {
cache.remove(pair);
}
} else {
return true;
}
}
private boolean notSoftSubtypeRecursive(Type t, Type s) {
TypePair pair = new TypePair(t, s);
if (cache.add(pair)) {
try {
return Types.this.notSoftSubtype(t, s);
} finally {
cache.remove(pair);
}
} else {
return false;
}
}
@Override
public Boolean visitWildcardType(WildcardType t, Type s) {
if (t.isUnbound())
return false;
if (!s.hasTag(WILDCARD)) {
if (t.isExtendsBound())
return notSoftSubtypeRecursive(s, t.type);
else
return notSoftSubtypeRecursive(t.type, s);
}
if (s.isUnbound())
return false;
if (t.isExtendsBound()) {
if (s.isExtendsBound())
return !isCastableRecursive(t.type, wildUpperBound(s));
else if (s.isSuperBound())
return notSoftSubtypeRecursive(wildLowerBound(s), t.type);
} else if (t.isSuperBound()) {
if (s.isExtendsBound())
return notSoftSubtypeRecursive(t.type, wildUpperBound(s));
}
return false;
}
};
//
//
public List cvarLowerBounds(List ts) {
return ts.map(cvarLowerBoundMapping);
}
private final TypeMapping cvarLowerBoundMapping = new TypeMapping() {
@Override
public Type visitCapturedType(CapturedType t, Void _unused) {
return cvarLowerBound(t);
}
};
//
//
/**
* 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 } but it is not true that Integer cannot
* possibly be a subtype of T.
*/
public boolean notSoftSubtype(Type t, Type s) {
if (t == s) return false;
if (t.hasTag(TYPEVAR)) {
TypeVar tv = (TypeVar) t;
return !isCastable(tv.bound,
relaxBound(s),
noWarnings);
}
if (!s.hasTag(WILDCARD))
s = cvarUpperBound(s);
return !isSubtype(t, relaxBound(s));
}
private Type relaxBound(Type t) {
return (t.hasTag(TYPEVAR)) ?
rewriteQuantifiers(skipTypeVars(t, false), true, true) :
t;
}
//
//
public boolean isReifiable(Type t) {
return isReifiable.visit(t);
}
// where
private UnaryVisitor isReifiable = new UnaryVisitor() {
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;
}
};
//
//
public boolean isArray(Type t) {
while (t.hasTag(WILDCARD))
t = wildUpperBound(t);
return t.hasTag(ARRAY);
}
/**
* The element type of an array.
*/
public Type elemtype(Type t) {
switch (t.getTag()) {
case WILDCARD:
return elemtype(wildUpperBound(t));
case ARRAY:
return ((ArrayType)t).elemtype;
case FORALL:
return elemtype(((ForAll)t).qtype);
case ERROR:
return t;
default:
return null;
}
}
public Type elemtypeOrType(Type t) {
Type elemtype = elemtype(t);
return elemtype != null ?
elemtype :
t;
}
/**
* Mapping to take element type of an arraytype
*/
private TypeMapping elemTypeFun = new TypeMapping() {
@Override
public Type visitArrayType(ArrayType t, Void _unused) {
return t.elemtype;
}
@Override
public Type visitTypeVar(TypeVar t, Void _unused) {
return visit(skipTypeVars(t, false));
}
};
/**
* The number of dimensions of an array type.
*/
public int dimensions(Type t) {
int result = 0;
while (t.hasTag(ARRAY)) {
result++;
t = elemtype(t);
}
return result;
}
/**
* Returns an ArrayType with the component type t
*
* @param t The component type of the ArrayType
* @return the ArrayType for the given component
*/
public ArrayType makeArrayType(Type t) {
if (t.hasTag(VOID) || t.hasTag(PACKAGE)) {
Assert.error("Type t must not be a VOID or PACKAGE type, " + t.toString());
}
return new ArrayType(t, syms.arrayClass);
}
//
//
/**
* Return the (most specific) base type of t that starts with the
* given symbol. If none exists, return null.
*
* Caveat Emptor: Since javac represents the class of all arrays with a singleton
* symbol Symtab.arrayClass, which by being a singleton cannot hold any discriminant,
* this method could yield surprising answers when invoked on arrays. For example when
* invoked with t being byte [] and sym being t.sym itself, asSuper would answer null.
*
* @param t a type
* @param sym a symbol
*/
public Type asSuper(Type t, Symbol sym) {
/* Some examples:
*
* (Enum, Comparable) => Comparable
* (c.s.s.d.AttributeTree.ValueKind, Enum) => Enum
* (c.s.s.t.ExpressionTree, c.s.s.t.Tree) => c.s.s.t.Tree
* (j.u.List, Iterable) =>
* Iterable
*/
if (sym.type == syms.objectType) { //optimization
return syms.objectType;
}
return asSuper.visit(t, sym);
}
// where
private SimpleVisitor asSuper = new SimpleVisitor() {
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 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;
}
}
//
//
/**
* 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 memberType = new SimpleVisitor() {
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 ownerParams = owner.type.allparams();
List 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;
}
};
//
//
public boolean isAssignable(Type t, Type s) {
return isAssignable(t, s, noWarnings);
}
/**
* Is t assignable to s?
* Equivalent to subtype except for constant values and raw
* types.
* (not defined for Method and ForAll types)
*/
public boolean isAssignable(Type t, Type s, Warner warn) {
if (t.hasTag(ERROR))
return true;
if (t.getTag().isSubRangeOf(INT) && t.constValue() != null) {
int value = ((Number)t.constValue()).intValue();
switch (s.getTag()) {
case BYTE:
case CHAR:
case SHORT:
case INT:
if (s.getTag().checkRange(value))
return true;
break;
case CLASS:
switch (unboxedType(s).getTag()) {
case BYTE:
case CHAR:
case SHORT:
return isAssignable(t, unboxedType(s), warn);
}
break;
}
}
return isConvertible(t, s, warn);
}
//
//
/**
* The erasure of t {@code |t|} -- the type that results when all
* type parameters in t are deleted.
*/
public Type erasure(Type t) {
return eraseNotNeeded(t) ? t : erasure(t, false);
}
//where
private boolean eraseNotNeeded(Type t) {
// We don't want to erase primitive types and String type as that
// operation is idempotent. Also, erasing these could result in loss
// of information such as constant values attached to such types.
return (t.isPrimitive()) || (syms.stringType.tsym == t.tsym);
}
private Type erasure(Type t, boolean recurse) {
if (t.isPrimitive()) {
return t; /* fast special case */
} else {
Type out = erasure.visit(t, recurse);
return out;
}
}
// where
private TypeMapping erasure = new StructuralTypeMapping() {
private Type combineMetadata(final Type s,
final Type t) {
if (t.getMetadata() != TypeMetadata.EMPTY) {
switch (s.getKind()) {
case OTHER:
case UNION:
case INTERSECTION:
case PACKAGE:
case EXECUTABLE:
case NONE:
case VOID:
case ERROR:
return s;
default: return s.cloneWithMetadata(s.getMetadata().without(Kind.ANNOTATIONS));
}
} else {
return s;
}
}
public Type visitType(Type t, Boolean recurse) {
if (t.isPrimitive())
return t; /*fast special case*/
else {
//other cases already handled
return combineMetadata(t, t);
}
}
@Override
public Type visitWildcardType(WildcardType t, Boolean recurse) {
Type erased = erasure(wildUpperBound(t), recurse);
return combineMetadata(erased, t);
}
@Override
public Type visitClassType(ClassType t, Boolean recurse) {
Type erased = t.tsym.erasure(Types.this);
if (recurse) {
erased = new ErasedClassType(erased.getEnclosingType(),erased.tsym,
t.getMetadata().without(Kind.ANNOTATIONS));
return erased;
} else {
return combineMetadata(erased, t);
}
}
@Override
public Type visitTypeVar(TypeVar t, Boolean recurse) {
Type erased = erasure(t.bound, recurse);
return combineMetadata(erased, t);
}
};
public List erasure(List ts) {
return erasure.visit(ts, false);
}
public Type erasureRecursive(Type t) {
return erasure(t, true);
}
public List erasureRecursive(List ts) {
return erasure.visit(ts, true);
}
//
//
/**
* 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 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 bounds, boolean allInterfaces) {
Assert.check(bounds.nonEmpty());
Type firstExplicitBound = bounds.head;
if (allInterfaces) {
bounds = bounds.prepend(syms.objectType);
}
ClassSymbol bc =
new ClassSymbol(ABSTRACT|PUBLIC|SYNTHETIC|COMPOUND|ACYCLIC,
Type.moreInfo
? names.fromString(bounds.toString())
: names.empty,
null,
syms.noSymbol);
IntersectionClassType intersectionType = new IntersectionClassType(bounds, bc, allInterfaces);
bc.type = intersectionType;
bc.erasure_field = (bounds.head.hasTag(TYPEVAR)) ?
syms.objectType : // error condition, recover
erasure(firstExplicitBound);
bc.members_field = WriteableScope.create(bc);
return intersectionType;
}
//
//
public Type supertype(Type t) {
return supertype.visit(t);
}
// where
private UnaryVisitor supertype = new UnaryVisitor() {
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 actuals = classBound(t).allparams();
List 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;
}
};
//
//
/**
* Return the interfaces implemented by this class.
*/
public List interfaces(Type t) {
return interfaces.visit(t);
}
// where
private UnaryVisitor> interfaces = new UnaryVisitor>() {
public List visitType(Type t, Void ignored) {
return List.nil();
}
@Override
public List visitClassType(ClassType t, Void ignored) {
if (t.interfaces_field == null) {
List 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
// Generic type declaration: class List { ... }
// So t corresponds to List and
// t.tsym.type corresponds to List.
// 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 actuals = t.allparams();
List 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 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 directSupertypes(Type t) {
return directSupertypes.visit(t);
}
// where
private final UnaryVisitor> directSupertypes = new UnaryVisitor>() {
public List visitType(final Type type, final Void ignored) {
if (!type.isIntersection()) {
final Type sup = supertype(type);
return (sup == Type.noType || sup == type || sup == null)
? interfaces(type)
: interfaces(type).prepend(sup);
} else {
return ((IntersectionClassType)type).getExplicitComponents();
}
}
};
public boolean isDirectSuperInterface(TypeSymbol isym, TypeSymbol origin) {
for (Type i2 : interfaces(origin.type)) {
if (isym == i2.tsym) return true;
}
return false;
}
//
//
Map isDerivedRawCache = new HashMap<>();
public boolean isDerivedRaw(Type t) {
Boolean result = isDerivedRawCache.get(t);
if (result == null) {
result = isDerivedRawInternal(t);
isDerivedRawCache.put(t, result);
}
return result;
}
public boolean isDerivedRawInternal(Type t) {
if (t.isErroneous())
return false;
return
t.isRaw() ||
supertype(t) != Type.noType && isDerivedRaw(supertype(t)) ||
isDerivedRaw(interfaces(t));
}
public boolean isDerivedRaw(List ts) {
List l = ts;
while (l.nonEmpty() && !isDerivedRaw(l.head)) l = l.tail;
return l.nonEmpty();
}
//
//
/**
* 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 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 bounds, boolean allInterfaces) {
t.bound = bounds.tail.isEmpty() ?
bounds.head :
makeIntersectionType(bounds, allInterfaces);
t.rank_field = -1;
}
//
//
/**
* Return list of bounds of the given type variable.
*/
public List 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);
}
//
//
/**
* 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 classBound = new UnaryVisitor() {
public Type visitType(Type t, Void ignored) {
return t;
}
@Override
public Type visitClassType(ClassType t, Void ignored) {
Type outer1 = classBound(t.getEnclosingType());
if (outer1 != t.getEnclosingType())
return new ClassType(outer1, t.getTypeArguments(), t.tsym,
t.getMetadata());
else
return t;
}
@Override
public Type visitTypeVar(TypeVar t, Void ignored) {
return classBound(supertype(t));
}
@Override
public Type visitErrorType(ErrorType t, Void ignored) {
return t;
}
};
//
//
/**
* Returns true iff the first signature is a sub
* signature of the other. This is not 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 override
* equivalence. This is the natural extension of
* isSubSignature to an equivalence relation.
*
* @jls section 8.4.2.
* @see #isSubSignature(Type t, Type s)
* @param t a signature (possible raw, could be subjected to
* erasure).
* @param s a signature (possible raw, could be subjected to
* erasure).
* @return true if either argument is a sub signature of the other.
*/
public boolean overrideEquivalent(Type t, Type s) {
return hasSameArgs(t, s) ||
hasSameArgs(t, erasure(s)) || hasSameArgs(erasure(t), s);
}
public boolean overridesObjectMethod(TypeSymbol origin, Symbol msym) {
for (Symbol sym : syms.objectType.tsym.members().getSymbolsByName(msym.name)) {
if (msym.overrides(sym, origin, Types.this, true)) {
return true;
}
}
return false;
}
/**
* This enum defines the strategy for implementing most specific return type check
* during the most specific and functional interface checks.
*/
public enum MostSpecificReturnCheck {
/**
* Return r1 is more specific than r2 if {@code r1 <: r2}. Extra care required for (i) handling
* method type variables (if either method is generic) and (ii) subtyping should be replaced
* by type-equivalence for primitives. This is essentially an inlined version of
* {@link Types#resultSubtype(Type, Type, Warner)}, where the assignability check has been
* replaced with a strict subtyping check.
*/
BASIC() {
@Override
public boolean test(Type mt1, Type mt2, Types types) {
List tvars = mt1.getTypeArguments();
List svars = mt2.getTypeArguments();
Type t = mt1.getReturnType();
Type s = types.subst(mt2.getReturnType(), svars, tvars);
return types.isSameType(t, s) ||
!t.isPrimitive() &&
!s.isPrimitive() &&
types.isSubtype(t, s);
}
},
/**
* Return r1 is more specific than r2 if r1 is return-type-substitutable for r2.
*/
RTS() {
@Override
public boolean test(Type mt1, Type mt2, Types types) {
return types.returnTypeSubstitutable(mt1, mt2);
}
};
public abstract boolean test(Type mt1, Type mt2, Types types);
}
/**
* Merge multiple abstract methods. The preferred method is a method that is a subsignature
* of all the other signatures and whose return type is more specific {@see MostSpecificReturnCheck}.
* The resulting preferred method has a thrown clause that is the intersection of the merged
* methods' clauses.
*/
public Optional mergeAbstracts(List ambiguousInOrder, Type site, boolean sigCheck) {
//first check for preconditions
boolean shouldErase = false;
List erasedParams = ambiguousInOrder.head.erasure(this).getParameterTypes();
for (Symbol s : ambiguousInOrder) {
if ((s.flags() & ABSTRACT) == 0 ||
(sigCheck && !isSameTypes(erasedParams, s.erasure(this).getParameterTypes()))) {
return Optional.empty();
} else if (s.type.hasTag(FORALL)) {
shouldErase = true;
}
}
//then merge abstracts
for (MostSpecificReturnCheck mostSpecificReturnCheck : MostSpecificReturnCheck.values()) {
outer: for (Symbol s : ambiguousInOrder) {
Type mt = memberType(site, s);
List allThrown = mt.getThrownTypes();
for (Symbol s2 : ambiguousInOrder) {
if (s != s2) {
Type mt2 = memberType(site, s2);
if (!isSubSignature(mt, mt2) ||
!mostSpecificReturnCheck.test(mt, mt2, this)) {
//ambiguity cannot be resolved
continue outer;
} else {
List thrownTypes2 = mt2.getThrownTypes();
if (!mt.hasTag(FORALL) && shouldErase) {
thrownTypes2 = erasure(thrownTypes2);
} else if (mt.hasTag(FORALL)) {
//subsignature implies that if most specific is generic, then all other
//methods are too
Assert.check(mt2.hasTag(FORALL));
// if both are generic methods, adjust thrown types ahead of intersection computation
thrownTypes2 = subst(thrownTypes2, mt2.getTypeArguments(), mt.getTypeArguments());
}
allThrown = chk.intersect(allThrown, thrownTypes2);
}
}
}
return (allThrown == mt.getThrownTypes()) ?
Optional.of(s) :
Optional.of(new MethodSymbol(
s.flags(),
s.name,
createMethodTypeWithThrown(s.type, allThrown),
s.owner) {
@Override
public Symbol baseSymbol() {
return s;
}
});
}
}
return Optional.empty();
}
//
class ImplementationCache {
private WeakHashMap>> _map = new WeakHashMap<>();
class Entry {
final MethodSymbol cachedImpl;
final Filter implFilter;
final boolean checkResult;
final int prevMark;
public Entry(MethodSymbol cachedImpl,
Filter scopeFilter,
boolean checkResult,
int prevMark) {
this.cachedImpl = cachedImpl;
this.implFilter = scopeFilter;
this.checkResult = checkResult;
this.prevMark = prevMark;
}
boolean matches(Filter scopeFilter, boolean checkResult, int mark) {
return this.implFilter == scopeFilter &&
this.checkResult == checkResult &&
this.prevMark == mark;
}
}
MethodSymbol get(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter implFilter) {
SoftReference> ref_cache = _map.get(ms);
Map cache = ref_cache != null ? ref_cache.get() : null;
if (cache == null) {
cache = new HashMap<>();
_map.put(ms, new SoftReference<>(cache));
}
Entry e = cache.get(origin);
CompoundScope members = membersClosure(origin.type, true);
if (e == null ||
!e.matches(implFilter, checkResult, members.getMark())) {
MethodSymbol impl = implementationInternal(ms, origin, checkResult, implFilter);
cache.put(origin, new Entry(impl, implFilter, checkResult, members.getMark()));
return impl;
}
else {
return e.cachedImpl;
}
}
private MethodSymbol implementationInternal(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter implFilter) {
for (Type t = origin.type; t.hasTag(CLASS) || t.hasTag(TYPEVAR); t = supertype(t)) {
t = skipTypeVars(t, false);
TypeSymbol c = t.tsym;
Symbol bestSoFar = null;
for (Symbol sym : c.members().getSymbolsByName(ms.name, implFilter)) {
if (sym != null && sym.overrides(ms, origin, Types.this, checkResult)) {
bestSoFar = sym;
if ((sym.flags() & ABSTRACT) == 0) {
//if concrete impl is found, exit immediately
break;
}
}
}
if (bestSoFar != null) {
//return either the (only) concrete implementation or the first abstract one
return (MethodSymbol)bestSoFar;
}
}
return null;
}
}
private ImplementationCache implCache = new ImplementationCache();
public MethodSymbol implementation(MethodSymbol ms, TypeSymbol origin, boolean checkResult, Filter implFilter) {
return implCache.get(ms, origin, checkResult, implFilter);
}
//
//
class MembersClosureCache extends SimpleVisitor {
private Map _map = new HashMap<>();
Set seenTypes = new HashSet<>();
class MembersScope extends CompoundScope {
CompoundScope scope;
public MembersScope(CompoundScope scope) {
super(scope.owner);
this.scope = scope;
}
Filter combine(Filter sf) {
return s -> !s.owner.isInterface() && (sf == null || sf.accepts(s));
}
@Override
public Iterable getSymbols(Filter sf, LookupKind lookupKind) {
return scope.getSymbols(combine(sf), lookupKind);
}
@Override
public Iterable getSymbolsByName(Name name, Filter sf, LookupKind lookupKind) {
return scope.getSymbolsByName(name, combine(sf), lookupKind);
}
@Override
public int getMark() {
return scope.getMark();
}
}
CompoundScope nilScope;
/** members closure visitor methods **/
public CompoundScope visitType(Type t, Void _unused) {
if (nilScope == null) {
nilScope = new CompoundScope(syms.noSymbol);
}
return nilScope;
}
@Override
public CompoundScope visitClassType(ClassType t, Void _unused) {
if (!seenTypes.add(t.tsym)) {
//this is possible when an interface is implemented in multiple
//superclasses, or when a class hierarchy is circular - in such
//cases we don't need to recurse (empty scope is returned)
return new CompoundScope(t.tsym);
}
try {
seenTypes.add(t.tsym);
ClassSymbol csym = (ClassSymbol)t.tsym;
CompoundScope membersClosure = _map.get(csym);
if (membersClosure == null) {
membersClosure = new CompoundScope(csym);
for (Type i : interfaces(t)) {
membersClosure.prependSubScope(visit(i, null));
}
membersClosure.prependSubScope(visit(supertype(t), null));
membersClosure.prependSubScope(csym.members());
_map.put(csym, membersClosure);
}
return membersClosure;
}
finally {
seenTypes.remove(t.tsym);
}
}
@Override
public CompoundScope visitTypeVar(TypeVar t, Void _unused) {
return visit(t.getUpperBound(), null);
}
}
private MembersClosureCache membersCache = new MembersClosureCache();
public CompoundScope membersClosure(Type site, boolean skipInterface) {
CompoundScope cs = membersCache.visit(site, null);
Assert.checkNonNull(cs, () -> "type " + site);
return skipInterface ? membersCache.new MembersScope(cs) : cs;
}
//
/** Return first abstract member of class `sym'.
*/
public MethodSymbol firstUnimplementedAbstract(ClassSymbol sym) {
try {
return firstUnimplementedAbstractImpl(sym, sym);
} catch (CompletionFailure ex) {
chk.completionError(enter.getEnv(sym).tree.pos(), ex);
return null;
}
}
//where:
private MethodSymbol firstUnimplementedAbstractImpl(ClassSymbol impl, ClassSymbol c) {
MethodSymbol undef = null;
// Do not bother to search in classes that are not abstract,
// since they cannot have abstract members.
if (c == impl || (c.flags() & (ABSTRACT | INTERFACE)) != 0) {
Scope s = c.members();
for (Symbol sym : s.getSymbols(NON_RECURSIVE)) {
if (sym.kind == MTH &&
(sym.flags() & (ABSTRACT|DEFAULT|PRIVATE)) == ABSTRACT) {
MethodSymbol absmeth = (MethodSymbol)sym;
MethodSymbol implmeth = absmeth.implementation(impl, this, true);
if (implmeth == null || implmeth == absmeth) {
//look for default implementations
if (allowDefaultMethods) {
MethodSymbol prov = interfaceCandidates(impl.type, absmeth).head;
if (prov != null && prov.overrides(absmeth, impl, this, true)) {
implmeth = prov;
}
}
}
if (implmeth == null || implmeth == absmeth) {
undef = absmeth;
break;
}
}
}
if (undef == null) {
Type st = supertype(c.type);
if (st.hasTag(CLASS))
undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)st.tsym);
}
for (List l = interfaces(c.type);
undef == null && l.nonEmpty();
l = l.tail) {
undef = firstUnimplementedAbstractImpl(impl, (ClassSymbol)l.head.tsym);
}
}
return undef;
}
public class CandidatesCache {
public Map> cache = new WeakHashMap<>();
class Entry {
Type site;
MethodSymbol msym;
Entry(Type site, MethodSymbol msym) {
this.site = site;
this.msym = msym;
}
@Override
public boolean equals(Object obj) {
if (obj instanceof Entry) {
Entry e = (Entry)obj;
return e.msym == msym && isSameType(site, e.site);
} else {
return false;
}
}
@Override
public int hashCode() {
return Types.this.hashCode(site) & ~msym.hashCode();
}
}
public List get(Entry e) {
return cache.get(e);
}
public void put(Entry e, List msymbols) {
cache.put(e, msymbols);
}
}
public CandidatesCache candidatesCache = new CandidatesCache();
//where
public List interfaceCandidates(Type site, MethodSymbol ms) {
CandidatesCache.Entry e = candidatesCache.new Entry(site, ms);
List candidates = candidatesCache.get(e);
if (candidates == null) {
Filter filter = new MethodFilter(ms, site);
List candidates2 = List.nil();
for (Symbol s : membersClosure(site, false).getSymbols(filter)) {
if (!site.tsym.isInterface() && !s.owner.isInterface()) {
return List.of((MethodSymbol)s);
} else if (!candidates2.contains(s)) {
candidates2 = candidates2.prepend((MethodSymbol)s);
}
}
candidates = prune(candidates2);
candidatesCache.put(e, candidates);
}
return candidates;
}
public List prune(List methods) {
ListBuffer 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 msym;
Type site;
MethodFilter(Symbol msym, Type site) {
this.msym = msym;
this.site = site;
}
public boolean accepts(Symbol s) {
return s.kind == MTH &&
s.name == msym.name &&
(s.flags() & SYNTHETIC) == 0 &&
s.isInheritedIn(site.tsym, Types.this) &&
overrideEquivalent(memberType(site, s), memberType(site, msym));
}
}
//
/**
* 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);
//
//
public List subst(List ts,
List from,
List to) {
return ts.map(new Subst(from, to));
}
/**
* Substitute all occurrences of a type in `from' with the
* corresponding type in `to' in 't'. Match lists `from' and `to'
* from the right: If lists have different length, discard leading
* elements of the longer list.
*/
public Type subst(Type t, List from, List to) {
return t.map(new Subst(from, to));
}
private class Subst extends StructuralTypeMapping {
List from;
List to;
public Subst(List from, List to) {
int fromLength = from.length();
int toLength = to.length();
while (fromLength > toLength) {
fromLength--;
from = from.tail;
}
while (fromLength < toLength) {
toLength--;
to = to.tail;
}
this.from = from;
this.to = to;
}
@Override
public Type visitTypeVar(TypeVar t, Void ignored) {
for (List from = this.from, to = this.to;
from.nonEmpty();
from = from.tail, to = to.tail) {
if (t.equalsIgnoreMetadata(from.head)) {
return to.head.withTypeVar(t);
}
}
return t;
}
@Override
public Type visitClassType(ClassType t, Void ignored) {
if (!t.isCompound()) {
return super.visitClassType(t, ignored);
} else {
Type st = visit(supertype(t));
List is = visit(interfaces(t), ignored);
if (st == supertype(t) && is == interfaces(t))
return t;
else
return makeIntersectionType(is.prepend(st));
}
}
@Override
public Type visitWildcardType(WildcardType t, Void ignored) {
WildcardType t2 = (WildcardType)super.visitWildcardType(t, ignored);
if (t2 != t && t.isExtendsBound() && t2.type.isExtendsBound()) {
t2.type = wildUpperBound(t2.type);
}
return t2;
}
@Override
public Type visitForAll(ForAll t, Void ignored) {
if (Type.containsAny(to, t.tvars)) {
//perform alpha-renaming of free-variables in 't'
//if 'to' types contain variables that are free in 't'
List freevars = newInstances(t.tvars);
t = new ForAll(freevars,
Types.this.subst(t.qtype, t.tvars, freevars));
}
List tvars1 = substBounds(t.tvars, from, to);
Type qtype1 = visit(t.qtype);
if (tvars1 == t.tvars && qtype1 == t.qtype) {
return t;
} else if (tvars1 == t.tvars) {
return new ForAll(tvars1, qtype1) {
@Override
public boolean needsStripping() {
return true;
}
};
} else {
return new ForAll(tvars1, Types.this.subst(qtype1, t.tvars, tvars1)) {
@Override
public boolean needsStripping() {
return true;
}
};
}
}
}
public List substBounds(List tvars,
List from,
List to) {
if (tvars.isEmpty())
return tvars;
ListBuffer 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 newTvars = new ListBuffer<>();
// create new type variables without bounds
for (Type t : tvars) {
newTvars.append(new TypeVar(t.tsym, null, syms.botType,
t.getMetadata()));
}
// the new bounds should use the new type variables in place
// of the old
List 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 from, List to) {
Type bound1 = subst(t.bound, from, to);
if (bound1 == t.bound)
return t;
else {
// create new type variable without bounds
TypeVar tv = new TypeVar(t.tsym, null, syms.botType,
t.getMetadata());
// the new bound should use the new type variable in place
// of the old
tv.bound = subst(bound1, List.of(t), List.of(tv));
return tv;
}
}
//
//
/**
* Does t have the same bounds for quantified variables as s?
*/
public boolean hasSameBounds(ForAll t, ForAll s) {
List l1 = t.tvars;
List 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();
}
//
//
/** Create new vector of type variables from list of variables
* changing all recursive bounds from old to new list.
*/
public List newInstances(List tvars) {
List tvars1 = tvars.map(newInstanceFun);
for (List l = tvars1; l.nonEmpty(); l = l.tail) {
TypeVar tv = (TypeVar) l.head;
tv.bound = subst(tv.bound, tvars, tvars1);
}
return tvars1;
}
private static final TypeMapping newInstanceFun = new TypeMapping() {
@Override
public TypeVar visitTypeVar(TypeVar t, Void _unused) {
return new TypeVar(t.tsym, t.getUpperBound(), t.getLowerBound(), t.getMetadata());
}
};
//
public Type createMethodTypeWithParameters(Type original, List newParams) {
return original.accept(methodWithParameters, newParams);
}
// where
private final MapVisitor> methodWithParameters = new MapVisitor>() {
public Type visitType(Type t, List newParams) {
throw new IllegalArgumentException("Not a method type: " + t);
}
public Type visitMethodType(MethodType t, List newParams) {
return new MethodType(newParams, t.restype, t.thrown, t.tsym);
}
public Type visitForAll(ForAll t, List newParams) {
return new ForAll(t.tvars, t.qtype.accept(this, newParams));
}
};
public Type createMethodTypeWithThrown(Type original, List newThrown) {
return original.accept(methodWithThrown, newThrown);
}
// where
private final MapVisitor> methodWithThrown = new MapVisitor>() {
public Type visitType(Type t, List newThrown) {
throw new IllegalArgumentException("Not a method type: " + t);
}
public Type visitMethodType(MethodType t, List newThrown) {
return new MethodType(t.argtypes, t.restype, newThrown, t.tsym);
}
public Type visitForAll(ForAll t, List 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 methodWithReturn = new MapVisitor() {
public Type visitType(Type t, Type newReturn) {
throw new IllegalArgumentException("Not a method type: " + t);
}
public Type visitMethodType(MethodType t, Type newReturn) {
return new MethodType(t.argtypes, newReturn, t.thrown, t.tsym) {
@Override
public Type baseType() {
return t;
}
};
}
public Type visitForAll(ForAll t, Type newReturn) {
return new ForAll(t.tvars, t.qtype.accept(this, newReturn)) {
@Override
public Type baseType() {
return t;
}
};
}
};
//
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);
}
//
//
/**
* The rank of a class is the length of the longest path between
* the class and java.lang.Object in the class inheritance
* graph. Undefined for all but reference types.
*/
public int rank(Type t) {
switch(t.getTag()) {
case CLASS: {
ClassType cls = (ClassType)t;
if (cls.rank_field < 0) {
Name fullname = cls.tsym.getQualifiedName();
if (fullname == names.java_lang_Object)
cls.rank_field = 0;
else {
int r = rank(supertype(cls));
for (List 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 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();
}
}
//
/**
* 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);
}
//
/**
* 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 tvars) {
StringBuilder s = new StringBuilder();
s.append('<');
boolean first = true;
for (Type t : tvars) {
if (!first) s.append(", ");
first = false;
appendTyparamString(((TypeVar)t), s);
}
s.append('>');
return s.toString();
}
private void appendTyparamString(TypeVar t, StringBuilder buf) {
buf.append(t);
if (t.bound == null ||
t.bound.tsym.getQualifiedName() == names.java_lang_Object)
return;
buf.append(" extends "); // Java syntax; no need for i18n
Type bound = t.bound;
if (!bound.isCompound()) {
buf.append(bound);
} else if ((erasure(t).tsym.flags() & INTERFACE) == 0) {
buf.append(supertype(t));
for (Type intf : interfaces(t)) {
buf.append('&');
buf.append(intf);
}
} else {
// No superclass was given in bounds.
// In this case, supertype is Object, erasure is first interface.
boolean first = true;
for (Type intf : interfaces(t)) {
if (!first) buf.append('&');
first = false;
buf.append(intf);
}
}
}
//
//
/**
* A cache for closures.
*
* 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> closureCache = new HashMap<>();
/**
* Returns the closure of a class or interface type.
*/
public List closure(Type t) {
List 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 l = interfaces(t); l.nonEmpty(); l = l.tail)
cl = union(cl, closure(l.head));
closureCache.put(t, cl);
}
return cl;
}
/**
* Collect types into a new closure (using a @code{ClosureHolder})
*/
public Collector> closureCollector(boolean minClosure, BiPredicate shouldSkip) {
return Collector.of(() -> new ClosureHolder(minClosure, shouldSkip),
ClosureHolder::add,
ClosureHolder::merge,
ClosureHolder::closure);
}
//where
class ClosureHolder {
List closure;
final boolean minClosure;
final BiPredicate shouldSkip;
ClosureHolder(boolean minClosure, BiPredicate shouldSkip) {
this.closure = List.nil();
this.minClosure = minClosure;
this.shouldSkip = shouldSkip;
}
void add(Type type) {
closure = insert(closure, type, shouldSkip);
}
ClosureHolder merge(ClosureHolder other) {
closure = union(closure, other.closure, shouldSkip);
return this;
}
List closure() {
return minClosure ? closureMin(closure) : closure;
}
}
BiPredicate basicClosureSkip = (t1, t2) -> t1.tsym == t2.tsym;
/**
* Insert a type in a closure
*/
public List insert(List cl, Type t, BiPredicate shouldSkip) {
if (cl.isEmpty()) {
return cl.prepend(t);
} else if (shouldSkip.test(t, cl.head)) {
return cl;
} else if (t.tsym.precedes(cl.head.tsym, this)) {
return cl.prepend(t);
} else {
// t comes after head, or the two are unrelated
return insert(cl.tail, t, shouldSkip).prepend(cl.head);
}
}
public List insert(List cl, Type t) {
return insert(cl, t, basicClosureSkip);
}
/**
* Form the union of two closures
*/
public List union(List cl1, List cl2, BiPredicate shouldSkip) {
if (cl1.isEmpty()) {
return cl2;
} else if (cl2.isEmpty()) {
return cl1;
} else if (shouldSkip.test(cl1.head, cl2.head)) {
return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
} else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
} else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
} else {
// unrelated types
return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
}
}
public List union(List cl1, List cl2) {
return union(cl1, cl2, basicClosureSkip);
}
/**
* Intersect two closures
*/
public List intersect(List cl1, List 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;;
TypePair(Type t1, Type t2) {
this.t1 = t1;
this.t2 = t2;
}
@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)
&& isSameType(t2, typePair.t2);
}
}
Set mergeCache = new HashSet<>();
private Type merge(Type c1, Type c2) {
ClassType class1 = (ClassType) c1;
List act1 = class1.getTypeArguments();
ClassType class2 = (ClassType) c2;
List act2 = class2.getTypeArguments();
ListBuffer merged = new ListBuffer<>();
List typarams = class1.tsym.type.getTypeArguments();
while (act1.nonEmpty() && act2.nonEmpty() && typarams.nonEmpty()) {
if (containsType(act1.head, act2.head)) {
merged.append(act1.head);
} else if (containsType(act2.head, act1.head)) {
merged.append(act2.head);
} else {
TypePair pair = new TypePair(c1, c2);
Type m;
if (mergeCache.add(pair)) {
m = new WildcardType(lub(wildUpperBound(act1.head),
wildUpperBound(act2.head)),
BoundKind.EXTENDS,
syms.boundClass);
mergeCache.remove(pair);
} else {
m = new WildcardType(syms.objectType,
BoundKind.UNBOUND,
syms.boundClass);
}
merged.append(m.withTypeVar(typarams.head));
}
act1 = act1.tail;
act2 = act2.tail;
typarams = typarams.tail;
}
Assert.check(act1.isEmpty() && act2.isEmpty() && typarams.isEmpty());
// There is no spec detailing how type annotations are to
// be inherited. So set it to noAnnotations for now
return new ClassType(class1.getEnclosingType(), merged.toList(),
class1.tsym);
}
/**
* Return the minimum type of a closure, a compound type if no
* unique minimum exists.
*/
private Type compoundMin(List cl) {
if (cl.isEmpty()) return syms.objectType;
List 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 closureMin(List cl) {
ListBuffer classes = new ListBuffer<>();
ListBuffer interfaces = new ListBuffer<>();
Set 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 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 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 mec = closureMin(cl);
//step 3 - for each element G in MEC, compute lci(Inv(G))
List candidates = List.nil();
for (Type erasedSupertype : mec) {
List lci = List.of(asSuper(ts[startIdx], erasedSupertype.tsym));
for (int i = startIdx + 1 ; i < ts.length ; i++) {
Type superType = asSuper(ts[i], erasedSupertype.tsym);
lci = intersect(lci, superType != null ? List.of(superType) : List.nil());
}
candidates = candidates.appendList(lci);
}
//step 4 - let MEC be { G1, G2 ... Gn }, then we have that
//lub = lci(Inv(G1)) & lci(Inv(G2)) & ... & lci(Inv(Gn))
return compoundMin(candidates);
default:
// calculate lub(A, B[])
List 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 erasedSupertypes(Type t) {
ListBuffer 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;
}
//
//
public Type glb(List 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 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 flatBounds, Type errT) {
List 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 cvars = List.nil();
List lowers = List.nil();
for (Type bound : bounds) {
if (!bound.isInterface()) {
classCount++;
Type lower = cvarLowerBound(bound);
if (bound != lower && !lower.hasTag(BOT)) {
cvars = cvars.append(bound);
lowers = lowers.append(lower);
}
}
}
if (classCount > 1) {
if (lowers.isEmpty()) {
return createErrorType(errT);
} else {
// try again with lower bounds included instead of capture variables
List newBounds = bounds.diff(cvars).appendList(lowers);
return glb(newBounds);
}
}
}
return makeIntersectionType(bounds);
}
//
//
/**
* Compute a hash code on a type.
*/
public int hashCode(Type t) {
return hashCode(t, false);
}
public int hashCode(Type t, boolean strict) {
return strict ?
hashCodeStrictVisitor.visit(t) :
hashCodeVisitor.visit(t);
}
// where
private static final HashCodeVisitor hashCodeVisitor = new HashCodeVisitor();
private static final HashCodeVisitor hashCodeStrictVisitor = new HashCodeVisitor() {
@Override
public Integer visitTypeVar(TypeVar t, Void ignored) {
return System.identityHashCode(t);
}
};
private static class HashCodeVisitor extends UnaryVisitor {
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 thisargs = t.argtypes;
thisargs.tail != null;
thisargs = thisargs.tail)
h = (h << 5) + visit(thisargs.head);
return (h << 5) + visit(t.restype);
}
@Override
public Integer visitWildcardType(WildcardType t, Void ignored) {
int result = t.kind.hashCode();
if (t.type != null) {
result *= 127;
result += visit(t.type);
}
return result;
}
@Override
public Integer visitArrayType(ArrayType t, Void ignored) {
return visit(t.elemtype) + 12;
}
@Override
public Integer visitTypeVar(TypeVar t, Void ignored) {
return System.identityHashCode(t);
}
@Override
public Integer visitUndetVar(UndetVar t, Void ignored) {
return System.identityHashCode(t);
}
@Override
public Integer visitErrorType(ErrorType t, Void ignored) {
return 0;
}
}
//
//
/**
* 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 tvars = t.getTypeArguments();
List svars = s.getTypeArguments();
Type tres = t.getReturnType();
Type sres = subst(s.getReturnType(), svars, tvars);
return covariantReturnType(tres, sres, warner);
}
/**
* Return-Type-Substitutable.
* @jls section 8.4.5
*/
public boolean returnTypeSubstitutable(Type r1, Type r2) {
if (hasSameArgs(r1, r2))
return resultSubtype(r1, r2, noWarnings);
else
return covariantReturnType(r1.getReturnType(),
erasure(r2.getReturnType()),
noWarnings);
}
public boolean returnTypeSubstitutable(Type r1,
Type r2, Type r2res,
Warner warner) {
if (isSameType(r1.getReturnType(), r2res))
return true;
if (r1.getReturnType().isPrimitive() || r2res.isPrimitive())
return false;
if (hasSameArgs(r1, r2))
return covariantReturnType(r1.getReturnType(), r2res, warner);
if (isSubtypeUnchecked(r1.getReturnType(), r2res, warner))
return true;
if (!isSubtype(r1.getReturnType(), erasure(r2res)))
return false;
warner.warn(LintCategory.UNCHECKED);
return true;
}
/**
* Is t an appropriate return type in an overrider for a
* method that returns s?
*/
public boolean covariantReturnType(Type t, Type s, Warner warner) {
return
isSameType(t, s) ||
!t.isPrimitive() &&
!s.isPrimitive() &&
isAssignable(t, s, warner);
}
//
//
/**
* Return the class that boxes the given primitive.
*/
public ClassSymbol boxedClass(Type t) {
return syms.enterClass(syms.java_base, syms.boxedName[t.getTag().ordinal()]);
}
/**
* Return the boxed type if 't' is primitive, otherwise return 't' itself.
*/
public Type boxedTypeOrType(Type t) {
return t.isPrimitive() ?
boxedClass(t).type :
t;
}
/**
* Return the primitive type corresponding to a boxed type.
*/
public Type unboxedType(Type t) {
for (int i=0; i
//
/*
* 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 to G,
* 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 capture(List ts) {
List buf = List.nil();
for (Type t : ts) {
buf = buf.prepend(capture(t));
}
return buf.reverse();
}
public Type capture(Type t) {
if (!t.hasTag(CLASS)) {
return t;
}
if (t.getEnclosingType() != Type.noType) {
Type capturedEncl = capture(t.getEnclosingType());
if (capturedEncl != t.getEnclosingType()) {
Type type1 = memberType(capturedEncl, t.tsym);
t = subst(type1, t.tsym.type.getTypeArguments(), t.getTypeArguments());
}
}
ClassType cls = (ClassType)t;
if (cls.isRaw() || !cls.isParameterized())
return cls;
ClassType G = (ClassType)cls.asElement().asType();
List A = G.getTypeArguments();
List T = cls.getTypeArguments();
List S = freshTypeVariables(T);
List currentA = A;
List currentT = T;
List currentS = S;
boolean captured = false;
while (!currentA.isEmpty() &&
!currentT.isEmpty() &&
!currentS.isEmpty()) {
if (currentS.head != currentT.head) {
captured = true;
WildcardType Ti = (WildcardType)currentT.head;
Type Ui = currentA.head.getUpperBound();
CapturedType Si = (CapturedType)currentS.head;
if (Ui == null)
Ui = syms.objectType;
switch (Ti.kind) {
case UNBOUND:
Si.bound = subst(Ui, A, S);
Si.lower = syms.botType;
break;
case EXTENDS:
Si.bound = glb(Ti.getExtendsBound(), subst(Ui, A, S));
Si.lower = syms.botType;
break;
case SUPER:
Si.bound = subst(Ui, A, S);
Si.lower = Ti.getSuperBound();
break;
}
Type tmpBound = Si.bound.hasTag(UNDETVAR) ? ((UndetVar)Si.bound).qtype : Si.bound;
Type tmpLower = Si.lower.hasTag(UNDETVAR) ? ((UndetVar)Si.lower).qtype : Si.lower;
if (!Si.bound.hasTag(ERROR) &&
!Si.lower.hasTag(ERROR) &&
isSameType(tmpBound, tmpLower)) {
currentS.head = Si.bound;
}
}
currentA = currentA.tail;
currentT = currentT.tail;
currentS = currentS.tail;
}
if (!currentA.isEmpty() || !currentT.isEmpty() || !currentS.isEmpty())
return erasure(t); // some "rare" type involved
if (captured)
return new ClassType(cls.getEnclosingType(), S, cls.tsym,
cls.getMetadata());
else
return t;
}
// where
public List freshTypeVariables(List types) {
ListBuffer result = new ListBuffer<>();
for (Type t : types) {
if (t.hasTag(WILDCARD)) {
Type bound = ((WildcardType)t).getExtendsBound();
if (bound == null)
bound = syms.objectType;
result.append(new CapturedType(capturedName,
syms.noSymbol,
bound,
syms.botType,
(WildcardType)t));
} else {
result.append(t);
}
}
return result.toList();
}
//
//
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 commonSupers = superClosure(to, erasure(from));
boolean giveWarning = commonSupers.isEmpty();
// The arguments to the supers could be unified here to
// get a more accurate analysis
while (commonSupers.nonEmpty()) {
Type t1 = asSuper(from, commonSupers.head.tsym);
Type t2 = commonSupers.head; // same as asSuper(to, commonSupers.head.tsym);
if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
return false;
giveWarning = giveWarning || (reverse ? giveWarning(t2, t1) : giveWarning(t1, t2));
commonSupers = commonSupers.tail;
}
if (giveWarning && !isReifiable(reverse ? from : to))
warn.warn(LintCategory.UNCHECKED);
return true;
}
private boolean sideCastFinal(Type from, Type to, Warner warn) {
// We are casting from type $from$ to type $to$, which are
// unrelated types one of which is final and the other of
// which is an interface. This method
// tries to reject a cast by transferring type parameters
// from the final class to the interface.
boolean reverse = false;
Type target = to;
if ((to.tsym.flags() & INTERFACE) == 0) {
Assert.check((from.tsym.flags() & INTERFACE) != 0);
reverse = true;
to = from;
from = target;
}
Assert.check((from.tsym.flags() & FINAL) != 0);
Type t1 = asSuper(from, to.tsym);
if (t1 == null) return false;
Type t2 = to;
if (disjointTypes(t1.getTypeArguments(), t2.getTypeArguments()))
return false;
if (!isReifiable(target) &&
(reverse ? giveWarning(t2, t1) : giveWarning(t1, t2)))
warn.warn(LintCategory.UNCHECKED);
return true;
}
private boolean giveWarning(Type from, Type to) {
List bounds = to.isCompound() ?
directSupertypes(to) : List.of(to);
for (Type b : bounds) {
Type subFrom = asSub(from, b.tsym);
if (b.isParameterized() &&
(!(isUnbounded(b) ||
isSubtype(from, b) ||
((subFrom != null) && containsType(b.allparams(), subFrom.allparams()))))) {
return true;
}
}
return false;
}
private List superClosure(Type t, Type s) {
List cl = List.nil();
for (List 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);
}
//
/**
* 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 from,
ListBuffer to) throws AdaptFailure {
new Adapter(from, to).adapt(source, target);
}
class Adapter extends SimpleVisitor {
ListBuffer from;
ListBuffer to;
Map mapping;
Adapter(ListBuffer from, ListBuffer to) {
this.from = from;
this.to = to;
mapping = new HashMap<>();
}
public void adapt(Type source, Type target) throws AdaptFailure {
visit(source, target);
List fromList = from.toList();
List 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 cache = new HashSet<>();
private void adaptRecursive(Type source, Type target) {
TypePair pair = new TypePair(source, target);
if (cache.add(pair)) {
try {
visit(source, target);
} finally {
cache.remove(pair);
}
}
}
private void adaptRecursive(List source, List 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 from,
ListBuffer 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);
}
}
//
/**
* 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} is rewritten to
* {@code List}. Since {@code List <:
* List} a {@code List} can be cast to {@code
* List} 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 {
boolean high;
boolean rewriteTypeVars;
Rewriter(boolean high, boolean rewriteTypeVars) {
this.high = high;
this.rewriteTypeVars = rewriteTypeVars;
}
@Override
public Type visitClassType(ClassType t, Void s) {
ListBuffer rewritten = new ListBuffer<>();
boolean changed = false;
for (Type arg : t.allparams()) {
Type bound = visit(arg);
if (arg != bound) {
changed = true;
}
rewritten.append(bound);
}
if (changed)
return subst(t.tsym.type,
t.tsym.type.allparams(),
rewritten.toList());
else
return t;
}
public Type visitType(Type t, Void s) {
return t;
}
@Override
public Type visitCapturedType(CapturedType t, Void s) {
Type w_bound = t.wildcard.type;
Type bound = w_bound.contains(t) ?
erasure(w_bound) :
visit(w_bound);
return rewriteAsWildcardType(visit(bound), t.wildcard.bound, t.wildcard.kind);
}
@Override
public Type visitTypeVar(TypeVar t, Void s) {
if (rewriteTypeVars) {
Type bound = t.bound.contains(t) ?
erasure(t.bound) :
visit(t.bound);
return rewriteAsWildcardType(bound, t, EXTENDS);
} else {
return t;
}
}
@Override
public Type visitWildcardType(WildcardType t, Void s) {
Type bound2 = visit(t.type);
return t.type == bound2 ? t : rewriteAsWildcardType(bound2, t.bound, t.kind);
}
private Type rewriteAsWildcardType(Type bound, TypeVar formal, BoundKind bk) {
switch (bk) {
case EXTENDS: return high ?
makeExtendsWildcard(B(bound), formal) :
makeExtendsWildcard(syms.objectType, formal);
case SUPER: return high ?
makeSuperWildcard(syms.botType, formal) :
makeSuperWildcard(B(bound), formal);
case UNBOUND: return makeExtendsWildcard(syms.objectType, formal);
default:
Assert.error("Invalid bound kind " + bk);
return null;
}
}
Type B(Type t) {
while (t.hasTag(WILDCARD)) {
WildcardType w = (WildcardType)t;
t = high ?
w.getExtendsBound() :
w.getSuperBound();
if (t == null) {
t = high ? syms.objectType : syms.botType;
}
}
return t;
}
}
/**
* Create a wildcard with the given upper (extends) bound; create
* an unbounded wildcard if bound is Object.
*
* @param bound the upper bound
* @param formal the formal type parameter that will be
* substituted by the wildcard
*/
private WildcardType makeExtendsWildcard(Type bound, TypeVar formal) {
if (bound == syms.objectType) {
return new WildcardType(syms.objectType,
BoundKind.UNBOUND,
syms.boundClass,
formal);
} else {
return new WildcardType(bound,
BoundKind.EXTENDS,
syms.boundClass,
formal);
}
}
/**
* Create a wildcard with the given lower (super) bound; create an
* unbounded wildcard if bound is bottom (type of {@code null}).
*
* @param bound the lower bound
* @param formal the formal type parameter that will be
* substituted by the wildcard
*/
private WildcardType makeSuperWildcard(Type bound, TypeVar formal) {
if (bound.hasTag(BOT)) {
return new WildcardType(syms.objectType,
BoundKind.UNBOUND,
syms.boundClass,
formal);
} else {
return new WildcardType(bound,
BoundKind.SUPER,
syms.boundClass,
formal);
}
}
/**
* A wrapper for a type that allows use in sets.
*/
public static class UniqueType {
public final Type type;
final Types types;
public UniqueType(Type type, Types types) {
this.type = type;
this.types = types;
}
public int hashCode() {
return types.hashCode(type);
}
public boolean equals(Object obj) {
return (obj instanceof UniqueType) &&
types.isSameType(type, ((UniqueType)obj).type);
}
public String toString() {
return type.toString();
}
}
//
//
/**
* 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 the return type of the operation implemented by this
* visitor; use Void if no return type is needed.
* @param 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 implements Type.Visitor {
final public R visit(Type t, S s) { return t.accept(this, s); }
public R visitClassType(ClassType t, S s) { return visitType(t, s); }
public R visitWildcardType(WildcardType t, S s) { return visitType(t, s); }
public R visitArrayType(ArrayType t, S s) { return visitType(t, s); }
public R visitMethodType(MethodType t, S s) { return visitType(t, s); }
public R visitPackageType(PackageType t, S s) { return visitType(t, s); }
public R visitModuleType(ModuleType t, S s) { return visitType(t, s); }
public R visitTypeVar(TypeVar t, S s) { return visitType(t, s); }
public R visitCapturedType(CapturedType t, S s) { return visitType(t, s); }
public R visitForAll(ForAll t, S s) { return visitType(t, s); }
public R visitUndetVar(UndetVar t, S s) { return visitType(t, s); }
public R visitErrorType(ErrorType t, S s) { return visitType(t, s); }
}
/**
* A default visitor for symbols. All visitor methods except
* visitSymbol are implemented by delegating to visitSymbol. Concrete
* subclasses must provide an implementation of visitSymbol and can
* override other methods as needed.
*
* @param the return type of the operation implemented by this
* visitor; use Void if no return type is needed.
* @param 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 implements Symbol.Visitor {
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 simple 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 the return type of the operation implemented by this
* visitor; use Void if no return type is needed.
* @param 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 extends DefaultTypeVisitor {
@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.
*
*/
public static abstract class TypeRelation extends SimpleVisitor {}
/**
* A convenience visitor for implementing operations that only
* require one argument (the type itself), that is, unary
* operations.
*
* @param the return type of the operation implemented by this
* visitor; use Void if no return type is needed.
*/
public static abstract class UnaryVisitor extends SimpleVisitor {
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 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 extends DefaultTypeVisitor {
final public Type visit(Type t) { return t.accept(this, null); }
public Type visitType(Type t, S s) { return t; }
}
/**
* An abstract class for mappings from types to types (see {@link Type#map(TypeMapping)}.
* This class implements the functional interface {@code Function}, that allows it to be used
* fluently in stream-like processing.
*/
public static class TypeMapping extends MapVisitor implements Function {
@Override
public Type apply(Type type) { return visit(type); }
List visit(List ts, S s) {
return ts.map(t -> visit(t, s));
}
@Override
public Type visitCapturedType(CapturedType t, S s) {
return visitTypeVar(t, s);
}
}
//
//
public RetentionPolicy getRetention(Attribute.Compound a) {
return getRetention(a.type.tsym);
}
public RetentionPolicy getRetention(TypeSymbol sym) {
RetentionPolicy vis = RetentionPolicy.CLASS; // the default
Attribute.Compound c = sym.attribute(syms.retentionType.tsym);
if (c != null) {
Attribute value = c.member(names.value);
if (value != null && value instanceof Attribute.Enum) {
Name levelName = ((Attribute.Enum)value).value.name;
if (levelName == names.SOURCE) vis = RetentionPolicy.SOURCE;
else if (levelName == names.CLASS) vis = RetentionPolicy.CLASS;
else if (levelName == names.RUNTIME) vis = RetentionPolicy.RUNTIME;
else ;// /* fail soft */ throw new AssertionError(levelName);
}
}
return vis;
}
//
//
public static abstract class SignatureGenerator {
public static class InvalidSignatureException extends RuntimeException {
private static final long serialVersionUID = 0;
private final Type type;
InvalidSignatureException(Type type) {
this.type = type;
}
public Type type() {
return type;
}
}
private final Types types;
protected abstract void append(char ch);
protected abstract void append(byte[] ba);
protected abstract void append(Name name);
protected void classReference(ClassSymbol c) { /* by default: no-op */ }
protected SignatureGenerator(Types types) {
this.types = types;
}
/**
* Assemble signature of given type in string buffer.
*/
public void assembleSig(Type type) {
switch (type.getTag()) {
case BYTE:
append('B');
break;
case SHORT:
append('S');
break;
case CHAR:
append('C');
break;
case INT:
append('I');
break;
case LONG:
append('J');
break;
case FLOAT:
append('F');
break;
case DOUBLE:
append('D');
break;
case BOOLEAN:
append('Z');
break;
case VOID:
append('V');
break;
case CLASS:
if (type.isCompound()) {
throw new InvalidSignatureException(type);
}
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 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:
if (((TypeVar)type).isCaptured()) {
throw new InvalidSignatureException(type);
}
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 l) {
while (l.nonEmpty()) {
if (l.head.hasTag(TypeTag.TYPEVAR)) {
return true;
}
l = l.tail;
}
return false;
}
public void assembleClassSig(Type type) {
ClassType ct = (ClassType) type;
ClassSymbol c = (ClassSymbol) ct.tsym;
classReference(c);
Type outer = ct.getEnclosingType();
if (outer.allparams().nonEmpty()) {
boolean rawOuter =
c.owner.kind == MTH || // either a local class
c.name == types.names.empty; // or anonymous
assembleClassSig(rawOuter
? types.erasure(outer)
: outer);
append(rawOuter ? '$' : '.');
Assert.check(c.flatname.startsWith(c.owner.enclClass().flatname));
append(rawOuter
? c.flatname.subName(c.owner.enclClass().flatname.getByteLength() + 1, c.flatname.getByteLength())
: c.name);
} else {
append(externalize(c.flatname));
}
if (ct.getTypeArguments().nonEmpty()) {
append('<');
assembleSig(ct.getTypeArguments());
append('>');
}
}
public void assembleParamsSig(List typarams) {
append('<');
for (List ts = typarams; ts.nonEmpty(); ts = ts.tail) {
Type.TypeVar tvar = (Type.TypeVar) ts.head;
append(tvar.tsym.name);
List bounds = types.getBounds(tvar);
if ((bounds.head.tsym.flags() & INTERFACE) != 0) {
append(':');
}
for (List l = bounds; l.nonEmpty(); l = l.tail) {
append(':');
assembleSig(l.head);
}
}
append('>');
}
private void assembleSig(List types) {
for (List ts = types; ts.nonEmpty(); ts = ts.tail) {
assembleSig(ts.head);
}
}
}
//
public void newRound() {
descCache._map.clear();
isDerivedRawCache.clear();
implCache._map.clear();
membersCache._map.clear();
closureCache.clear();
}
}