/**
* Check if cast from supertype to subtype is erased. It is an error in "is" statement and warning
* in "as".
*/
public static boolean isCastErased(
@NotNull KotlinType supertype,
@NotNull KotlinType subtype,
@NotNull KotlinTypeChecker typeChecker) {
// cast between T and T? is always OK
if (supertype.isMarkedNullable() || subtype.isMarkedNullable()) {
return isCastErased(
TypeUtils.makeNotNullable(supertype), TypeUtils.makeNotNullable(subtype), typeChecker);
}
// if it is a upcast, it's never erased
if (typeChecker.isSubtypeOf(supertype, subtype)) return false;
// downcasting to a non-reified type parameter is always erased
if (TypeUtils.isNonReifiedTypeParemeter(subtype)) return true;
// Check that we are actually casting to a generic type
// NOTE: this does not account for 'as Array<List<T>>'
if (allParametersReified(subtype)) return false;
KotlinType staticallyKnownSubtype =
findStaticallyKnownSubtype(supertype, subtype.getConstructor()).getResultingType();
// If the substitution failed, it means that the result is an impossible type, e.g. something
// like Out<in Foo>
// In this case, we can't guarantee anything, so the cast is considered to be erased
if (staticallyKnownSubtype == null) return true;
// If the type we calculated is a subtype of the cast target, it's OK to use the cast target
// instead.
// If not, it's wrong to use it
return !typeChecker.isSubtypeOf(staticallyKnownSubtype, subtype);
}
private static boolean isReturnTypeMoreSpecific(
@NotNull CallableDescriptor a,
@NotNull KotlinType aReturnType,
@NotNull CallableDescriptor b,
@NotNull KotlinType bReturnType) {
KotlinTypeChecker typeChecker =
DEFAULT.createTypeChecker(a.getTypeParameters(), b.getTypeParameters());
return typeChecker.isSubtypeOf(aReturnType, bReturnType);
}
@NotNull
public OverrideCompatibilityInfo isOverridableByWithoutExternalConditions(
@NotNull CallableDescriptor superDescriptor,
@NotNull CallableDescriptor subDescriptor,
boolean checkReturnType) {
OverrideCompatibilityInfo basicOverridability =
getBasicOverridabilityProblem(superDescriptor, subDescriptor);
if (basicOverridability != null) return basicOverridability;
List<KotlinType> superValueParameters = compiledValueParameters(superDescriptor);
List<KotlinType> subValueParameters = compiledValueParameters(subDescriptor);
List<TypeParameterDescriptor> superTypeParameters = superDescriptor.getTypeParameters();
List<TypeParameterDescriptor> subTypeParameters = subDescriptor.getTypeParameters();
if (superTypeParameters.size() != subTypeParameters.size()) {
for (int i = 0; i < superValueParameters.size(); ++i) {
// TODO: compare erasure
if (!KotlinTypeChecker.DEFAULT.equalTypes(
superValueParameters.get(i), subValueParameters.get(i))) {
return OverrideCompatibilityInfo.incompatible("Type parameter number mismatch");
}
}
return OverrideCompatibilityInfo.conflict("Type parameter number mismatch");
}
KotlinTypeChecker typeChecker = createTypeChecker(superTypeParameters, subTypeParameters);
for (int i = 0; i < superTypeParameters.size(); i++) {
if (!areTypeParametersEquivalent(
superTypeParameters.get(i), subTypeParameters.get(i), typeChecker)) {
return OverrideCompatibilityInfo.incompatible("Type parameter bounds mismatch");
}
}
for (int i = 0; i < superValueParameters.size(); i++) {
if (!areTypesEquivalent(
superValueParameters.get(i), subValueParameters.get(i), typeChecker)) {
return OverrideCompatibilityInfo.incompatible("Value parameter type mismatch");
}
}
if (checkReturnType) {
KotlinType superReturnType = superDescriptor.getReturnType();
KotlinType subReturnType = subDescriptor.getReturnType();
if (superReturnType != null && subReturnType != null) {
boolean bothErrors = subReturnType.isError() && superReturnType.isError();
if (!bothErrors && !typeChecker.isSubtypeOf(subReturnType, superReturnType)) {
return OverrideCompatibilityInfo.conflict("Return type mismatch");
}
}
}
return OverrideCompatibilityInfo.success();
}
private static boolean lowerThanBound(
KotlinTypeChecker typeChecker,
KotlinType argument,
TypeParameterDescriptor parameterDescriptor) {
for (KotlinType bound : parameterDescriptor.getUpperBounds()) {
if (typeChecker.isSubtypeOf(argument, bound)) {
if (!argument.getConstructor().equals(bound.getConstructor())) {
return true;
}
}
}
return false;
}
@NotNull
public OverrideCompatibilityInfo isOverridableByWithoutExternalConditions(
@NotNull CallableDescriptor superDescriptor,
@NotNull CallableDescriptor subDescriptor,
boolean checkReturnType) {
if (superDescriptor instanceof FunctionDescriptor
&& !(subDescriptor instanceof FunctionDescriptor)
|| superDescriptor instanceof PropertyDescriptor
&& !(subDescriptor instanceof PropertyDescriptor)) {
return OverrideCompatibilityInfo.incompatible("Member kind mismatch");
}
if (!(superDescriptor instanceof FunctionDescriptor)
&& !(superDescriptor instanceof PropertyDescriptor)) {
throw new IllegalArgumentException(
"This type of CallableDescriptor cannot be checked for overridability: "
+ superDescriptor);
}
// TODO: check outside of this method
if (!superDescriptor.getName().equals(subDescriptor.getName())) {
return OverrideCompatibilityInfo.incompatible("Name mismatch");
}
OverrideCompatibilityInfo receiverAndParameterResult =
checkReceiverAndParameterCount(superDescriptor, subDescriptor);
if (receiverAndParameterResult != null) {
return receiverAndParameterResult;
}
List<KotlinType> superValueParameters = compiledValueParameters(superDescriptor);
List<KotlinType> subValueParameters = compiledValueParameters(subDescriptor);
List<TypeParameterDescriptor> superTypeParameters = superDescriptor.getTypeParameters();
List<TypeParameterDescriptor> subTypeParameters = subDescriptor.getTypeParameters();
if (superTypeParameters.size() != subTypeParameters.size()) {
for (int i = 0; i < superValueParameters.size(); ++i) {
// TODO: compare erasure
if (!KotlinTypeChecker.DEFAULT.equalTypes(
superValueParameters.get(i), subValueParameters.get(i))) {
return OverrideCompatibilityInfo.incompatible("Type parameter number mismatch");
}
}
return OverrideCompatibilityInfo.conflict("Type parameter number mismatch");
}
KotlinTypeChecker typeChecker = createTypeChecker(superTypeParameters, subTypeParameters);
for (int i = 0; i < superTypeParameters.size(); i++) {
if (!areTypeParametersEquivalent(
superTypeParameters.get(i), subTypeParameters.get(i), typeChecker)) {
return OverrideCompatibilityInfo.incompatible("Type parameter bounds mismatch");
}
}
for (int i = 0; i < superValueParameters.size(); i++) {
if (!areTypesEquivalent(
superValueParameters.get(i), subValueParameters.get(i), typeChecker)) {
return OverrideCompatibilityInfo.incompatible("Value parameter type mismatch");
}
}
if (checkReturnType) {
KotlinType superReturnType = superDescriptor.getReturnType();
KotlinType subReturnType = subDescriptor.getReturnType();
if (superReturnType != null && subReturnType != null) {
boolean bothErrors = subReturnType.isError() && superReturnType.isError();
if (!bothErrors && !typeChecker.isSubtypeOf(subReturnType, superReturnType)) {
return OverrideCompatibilityInfo.conflict("Return type mismatch");
}
}
}
return OverrideCompatibilityInfo.success();
}