@Override
JSType resolveInternal(ErrorReporter t, StaticScope<JSType> scope) {
setResolvedTypeInternal(this);
call = (ArrowType) safeResolve(call, t, scope);
if (prototypeSlot != null) {
prototypeSlot.setType(safeResolve(prototypeSlot.getType(), t, scope));
}
// Warning about typeOfThis if it doesn't resolve to an ObjectType
// is handled further upstream.
//
// TODO(nicksantos): Handle this correctly if we have a UnionType.
JSType maybeTypeOfThis = safeResolve(typeOfThis, t, scope);
if (maybeTypeOfThis != null) {
if (maybeTypeOfThis.isNullType() || maybeTypeOfThis.isVoidType()) {
typeOfThis = maybeTypeOfThis;
} else {
maybeTypeOfThis = ObjectType.cast(maybeTypeOfThis.restrictByNotNullOrUndefined());
if (maybeTypeOfThis != null) {
typeOfThis = maybeTypeOfThis;
}
}
}
ImmutableList<ObjectType> resolvedImplemented =
resolveTypeListHelper(implementedInterfaces, t, scope);
if (resolvedImplemented != null) {
implementedInterfaces = resolvedImplemented;
}
ImmutableList<ObjectType> resolvedExtended =
resolveTypeListHelper(extendedInterfaces, t, scope);
if (resolvedExtended != null) {
extendedInterfaces = resolvedExtended;
}
if (subTypes != null) {
for (int i = 0; i < subTypes.size(); i++) {
subTypes.set(i, JSType.toMaybeFunctionType(subTypes.get(i).resolve(t, scope)));
}
}
return super.resolveInternal(t, scope);
}
/**
* A function is a subtype of another if their call methods are related via subtyping and {@code
* this} is a subtype of {@code that} with regard to the prototype chain.
*/
@Override
public boolean isSubtype(JSType that) {
if (JSType.isSubtypeHelper(this, that)) {
return true;
}
if (that.isFunctionType()) {
FunctionType other = that.toMaybeFunctionType();
if (other.isInterface()) {
// Any function can be assigned to an interface function.
return true;
}
if (isInterface()) {
// An interface function cannot be assigned to anything.
return false;
}
// If functionA is a subtype of functionB, then their "this" types
// should be contravariant. However, this causes problems because
// of the way we enforce overrides. Because function(this:SubFoo)
// is not a subtype of function(this:Foo), our override check treats
// this as an error. Let's punt on all this for now.
// TODO(nicksantos): fix this.
boolean treatThisTypesAsCovariant =
// An interface 'this'-type is non-restrictive.
// In practical terms, if C implements I, and I has a method m,
// then any m doesn't necessarily have to C#m's 'this'
// type doesn't need to match I.
(other.typeOfThis.toObjectType() != null
&& other.typeOfThis.toObjectType().getConstructor() != null
&& other.typeOfThis.toObjectType().getConstructor().isInterface())
||
// If one of the 'this' types is covariant of the other,
// then we'll treat them as covariant (see comment above).
other.typeOfThis.isSubtype(this.typeOfThis)
|| this.typeOfThis.isSubtype(other.typeOfThis);
return treatThisTypesAsCovariant && this.call.isSubtype(other.call);
}
return getNativeType(JSTypeNative.FUNCTION_PROTOTYPE).isSubtype(that);
}
/**
* Resolves a named type by looking up its first component in the scope, and subsequent components
* as properties. The scope must have been fully parsed and a symbol table constructed.
*/
private void resolveViaProperties(ErrorReporter reporter, StaticTypedScope<JSType> enclosing) {
JSType value = lookupViaProperties(reporter, enclosing);
// last component of the chain
if (value != null && value.isFunctionType() && (value.isConstructor() || value.isInterface())) {
FunctionType functionType = value.toMaybeFunctionType();
setReferencedAndResolvedType(functionType.getInstanceType(), reporter);
} else if (value != null && value.isNoObjectType()) {
setReferencedAndResolvedType(
registry.getNativeObjectType(JSTypeNative.NO_OBJECT_TYPE), reporter);
} else if (value instanceof EnumType) {
setReferencedAndResolvedType(((EnumType) value).getElementsType(), reporter);
} else {
// We've been running into issues where people forward-declare
// non-named types. (This is legitimate...our dependency management
// code doubles as our forward-declaration code.)
//
// So if the type does resolve to an actual value, but it's not named,
// then don't respect the forward declaration.
handleUnresolvedType(reporter, value == null || value.isUnknownType());
}
}
/** Adds an alternate to the union type under construction. Returns this for easy chaining. */
public UnionTypeBuilder addAlternate(JSType alternate, boolean isStructural) {
// build() returns the bottom type by default, so we can
// just bail out early here.
if (alternate.isNoType()) {
return this;
}
isAllType = isAllType || alternate.isAllType();
containsVoidType = containsVoidType || alternate.isVoidType();
boolean isAlternateUnknown = alternate instanceof UnknownType;
isNativeUnknownType = isNativeUnknownType || isAlternateUnknown;
if (isAlternateUnknown) {
areAllUnknownsChecked = areAllUnknownsChecked && alternate.isCheckedUnknownType();
}
if (!isAllType && !isNativeUnknownType) {
if (alternate.isUnionType()) {
UnionType union = alternate.toMaybeUnionType();
for (JSType unionAlt : union.getAlternatesWithoutStructuralTyping()) {
addAlternate(unionAlt);
}
} else {
if (alternates.size() > maxUnionSize) {
return this;
}
// Function types are special, because they have their
// own bizarre sub-lattice. See the comments on
// FunctionType#supAndInf helper and above at functionTypePosition.
if (alternate.isFunctionType() && functionTypePosition != -1) {
// See the comments on functionTypePosition above.
FunctionType other = alternates.get(functionTypePosition).toMaybeFunctionType();
FunctionType supremum = alternate.toMaybeFunctionType().supAndInfHelper(other, true);
alternates.set(functionTypePosition, supremum);
result = null;
return this;
}
// Look through the alternates we've got so far,
// and check if any of them are duplicates of
// one another.
int currentIndex = 0;
Iterator<JSType> it = alternates.iterator();
while (it.hasNext()) {
boolean removeCurrent = false;
JSType current = it.next();
// Unknown and NoResolved types may just be names that haven't
// been resolved yet. So keep these in the union, and just use
// equality checking for simple de-duping.
if (alternate.isUnknownType()
|| current.isUnknownType()
|| alternate.isNoResolvedType()
|| current.isNoResolvedType()
|| alternate.hasAnyTemplateTypes()
|| current.hasAnyTemplateTypes()) {
if (alternate.isEquivalentTo(current, isStructural)) {
// Alternate is unnecessary.
return this;
}
} else {
// Because "Foo" and "Foo.<?>" are roughly equivalent
// templatized types, special care is needed when building the
// union. For example:
// Object is consider a subtype of Object.<string>
// but we want to leave "Object" not "Object.<string>" when
// building the subtype.
//
if (alternate.isTemplatizedType() || current.isTemplatizedType()) {
// Cases:
// 1) alternate:Array.<string> and current:Object ==> Object
// 2) alternate:Array.<string> and current:Array ==> Array
// 3) alternate:Object.<string> and
// current:Array ==> Array|Object.<string>
// 4) alternate:Object and current:Array.<string> ==> Object
// 5) alternate:Array and current:Array.<string> ==> Array
// 6) alternate:Array and
// current:Object.<string> ==> Array|Object.<string>
// 7) alternate:Array.<string> and
// current:Array.<number> ==> Array.<?>
// 8) alternate:Array.<string> and
// current:Array.<string> ==> Array.<string>
// 9) alternate:Array.<string> and
// current:Object.<string> ==> Object.<string>|Array.<string>
if (!current.isTemplatizedType()) {
if (isSubtype(alternate, current, isStructural)) {
// case 1, 2
return this;
}
// case 3: leave current, add alternate
} else if (!alternate.isTemplatizedType()) {
if (isSubtype(current, alternate, isStructural)) {
// case 4, 5
removeCurrent = true;
}
// case 6: leave current, add alternate
} else {
Preconditions.checkState(
current.isTemplatizedType() && alternate.isTemplatizedType());
TemplatizedType templatizedAlternate = alternate.toMaybeTemplatizedType();
TemplatizedType templatizedCurrent = current.toMaybeTemplatizedType();
if (templatizedCurrent.wrapsSameRawType(templatizedAlternate)) {
if (alternate
.getTemplateTypeMap()
.checkEquivalenceHelper(
current.getTemplateTypeMap(),
EquivalenceMethod.IDENTITY,
SubtypingMode.NORMAL)) {
// case 8
return this;
} else {
// TODO(johnlenz): should we leave both types?
// case 7: add a merged alternate
// We currently merge to the templatized types to "unknown"
// which is equivalent to the raw type.
JSType merged = templatizedCurrent.getReferencedObjTypeInternal();
return addAlternate(merged);
}
}
// case 9: leave current, add alternate
}
// Otherwise leave both templatized types.
} else if (isSubtype(alternate, current, isStructural)) {
// Alternate is unnecessary.
return this;
} else if (isSubtype(current, alternate, isStructural)) {
// Alternate makes current obsolete
removeCurrent = true;
}
}
if (removeCurrent) {
it.remove();
if (currentIndex == functionTypePosition) {
functionTypePosition = -1;
} else if (currentIndex < functionTypePosition) {
functionTypePosition--;
currentIndex--;
}
}
currentIndex++;
}
if (alternate.isFunctionType()) {
// See the comments on functionTypePosition above.
Preconditions.checkState(functionTypePosition == -1);
functionTypePosition = alternates.size();
}
alternates.add(alternate);
result = null; // invalidate the memoized result
}
} else {
result = null;
}
return this;
}