private void addConstraint(
@NotNull ConstraintKind constraintKind,
@NotNull JetType subjectType,
@Nullable JetType constrainingType,
@NotNull ConstraintPosition constraintPosition) {
if (constrainingType == TypeUtils.NO_EXPECTED_TYPE
|| constrainingType == DONT_CARE
|| constrainingType == CANT_INFER) {
return;
}
if (constrainingType == null
|| (ErrorUtils.isErrorType(constrainingType)
&& constrainingType != PLACEHOLDER_FUNCTION_TYPE)) {
hasErrorInConstrainingTypes = true;
return;
}
assert subjectType != TypeUtils.NO_EXPECTED_TYPE
: "Subject type shouldn't be NO_EXPECTED_TYPE (in position " + constraintPosition + " )";
if (ErrorUtils.isErrorType(subjectType)) return;
DeclarationDescriptor subjectTypeDescriptor =
subjectType.getConstructor().getDeclarationDescriptor();
KotlinBuiltIns kotlinBuiltIns = KotlinBuiltIns.getInstance();
if (constrainingType == PLACEHOLDER_FUNCTION_TYPE) {
if (!kotlinBuiltIns.isFunctionOrExtensionFunctionType(subjectType)) {
if (subjectTypeDescriptor instanceof TypeParameterDescriptor
&& typeParameterConstraints.get(subjectTypeDescriptor) != null) {
// a constraint binds type parameter and any function type, so there is no new info and no
// error
return;
}
errorConstraintPositions.add(constraintPosition);
}
return;
}
// todo temporary hack
// function literal without declaring receiver type { x -> ... }
// can be considered as extension function if one is expected
// (special type constructor for function/ extension function should be introduced like
// PLACEHOLDER_FUNCTION_TYPE)
if (constraintKind == SUB_TYPE
&& kotlinBuiltIns.isFunctionType(constrainingType)
&& kotlinBuiltIns.isExtensionFunctionType(subjectType)) {
constrainingType = createCorrespondingExtensionFunctionType(constrainingType, DONT_CARE);
}
DeclarationDescriptor constrainingTypeDescriptor =
constrainingType.getConstructor().getDeclarationDescriptor();
if (subjectTypeDescriptor instanceof TypeParameterDescriptor) {
TypeParameterDescriptor typeParameter = (TypeParameterDescriptor) subjectTypeDescriptor;
TypeConstraintsImpl typeConstraints = typeParameterConstraints.get(typeParameter);
if (typeConstraints != null) {
if (TypeUtils.dependsOnTypeParameterConstructors(
constrainingType, Collections.singleton(DONT_CARE.getConstructor()))) {
return;
}
if (subjectType.isNullable() && constrainingType.isNullable()) {
constrainingType = TypeUtils.makeNotNullable(constrainingType);
}
typeConstraints.addBound(constraintKind, constrainingType);
return;
}
}
if (constrainingTypeDescriptor instanceof TypeParameterDescriptor) {
assert typeParameterConstraints.get(constrainingTypeDescriptor) == null
: "Constraining type contains type variable " + constrainingTypeDescriptor.getName();
}
if (constraintKind == SUB_TYPE && kotlinBuiltIns.isNothingOrNullableNothing(constrainingType)) {
// following constraints are always true:
// 'Nothing' is a subtype of any type
if (!constrainingType.isNullable()) return;
// 'Nothing?' is a subtype of nullable type
if (subjectType.isNullable()) return;
}
if (!(constrainingTypeDescriptor instanceof ClassDescriptor)
|| !(subjectTypeDescriptor instanceof ClassDescriptor)) {
errorConstraintPositions.add(constraintPosition);
return;
}
switch (constraintKind) {
case SUB_TYPE:
{
if (kotlinBuiltIns.isNothingOrNullableNothing(constrainingType)) break;
JetType correspondingSupertype =
TypeCheckingProcedure.findCorrespondingSupertype(constrainingType, subjectType);
if (correspondingSupertype != null) {
constrainingType = correspondingSupertype;
}
break;
}
case SUPER_TYPE:
{
if (kotlinBuiltIns.isNothingOrNullableNothing(subjectType)) break;
JetType correspondingSupertype =
TypeCheckingProcedure.findCorrespondingSupertype(subjectType, constrainingType);
if (correspondingSupertype != null) {
subjectType = correspondingSupertype;
}
}
case EQUAL: // nothing
}
if (constrainingType.getConstructor() != subjectType.getConstructor()) {
errorConstraintPositions.add(constraintPosition);
return;
}
TypeConstructor typeConstructor = subjectType.getConstructor();
List<TypeProjection> subjectArguments = subjectType.getArguments();
List<TypeProjection> constrainingArguments = constrainingType.getArguments();
List<TypeParameterDescriptor> parameters = typeConstructor.getParameters();
for (int i = 0; i < subjectArguments.size(); i++) {
Variance typeParameterVariance = parameters.get(i).getVariance();
TypeProjection subjectArgument = subjectArguments.get(i);
TypeProjection constrainingArgument = constrainingArguments.get(i);
ConstraintKind typeParameterConstraintKind =
getTypeParameterConstraintKind(
typeParameterVariance, subjectArgument, constrainingArgument, constraintKind);
addConstraint(
typeParameterConstraintKind,
subjectArgument.getType(),
constrainingArgument.getType(),
constraintPosition);
}
}
