static ObjectType meet(ObjectType obj1, ObjectType obj2) {
Preconditions.checkState(areRelatedClasses(obj1.nominalType, obj2.nominalType));
if (obj1 == TOP_OBJECT) {
return obj2;
} else if (obj2 == TOP_OBJECT) {
return obj1;
}
NominalType resultNomType = NominalType.pickSubclass(obj1.nominalType, obj2.nominalType);
FunctionType fn = FunctionType.meet(obj1.fn, obj2.fn);
if (!FunctionType.isInhabitable(fn)) {
return BOTTOM_OBJECT;
}
boolean isLoose = obj1.isLoose && obj2.isLoose || fn != null && fn.isLoose();
if (resultNomType != null && resultNomType.isFunction() && fn == null) {
fn = obj1.fn == null ? obj2.fn : obj1.fn;
isLoose = fn.isLoose();
}
PersistentMap<String, Property> props;
if (isLoose) {
props = joinPropsLoosely(obj1.props, obj2.props);
} else {
props = meetPropsHelper(false, resultNomType, obj1.props, obj2.props);
}
if (props == BOTTOM_MAP) {
return BOTTOM_OBJECT;
}
ObjectKind ok = ObjectKind.meet(obj1.objectKind, obj2.objectKind);
return new ObjectType(resultNomType, props, fn, isLoose, ok);
}
ObjectType specialize(ObjectType other) {
Preconditions.checkState(areRelatedClasses(this.nominalType, other.nominalType));
if (this == TOP_OBJECT && other.objectKind.isUnrestricted()) {
return other;
}
NominalType resultNomType = NominalType.pickSubclass(this.nominalType, other.nominalType);
ObjectKind ok = ObjectKind.meet(this.objectKind, other.objectKind);
if (resultNomType != null && resultNomType.isClassy()) {
Preconditions.checkState(this.fn == null && other.fn == null);
PersistentMap<String, Property> newProps =
meetPropsHelper(true, resultNomType, this.props, other.props);
if (newProps == BOTTOM_MAP) {
return BOTTOM_OBJECT;
}
return new ObjectType(resultNomType, newProps, null, false, ok);
}
FunctionType thisFn = this.fn;
boolean isLoose = this.isLoose;
if (resultNomType != null && resultNomType.isFunction() && this.fn == null) {
thisFn = other.fn;
isLoose = other.fn.isLoose();
}
PersistentMap<String, Property> newProps =
meetPropsHelper(true, resultNomType, this.props, other.props);
if (newProps == BOTTOM_MAP) {
return BOTTOM_OBJECT;
}
FunctionType newFn = thisFn == null ? null : thisFn.specialize(other.fn);
if (!FunctionType.isInhabitable(newFn)) {
return BOTTOM_OBJECT;
}
return new ObjectType(resultNomType, newProps, newFn, isLoose, ok);
}
