@Nullable
private static JetType computeUnsafeReturnType(
@NotNull JetFunctionLiteralExpression expression,
@NotNull ExpressionTypingContext context,
@NotNull SimpleFunctionDescriptorImpl functionDescriptor,
@Nullable JetType expectedReturnType) {
JetFunctionLiteral functionLiteral = expression.getFunctionLiteral();
JetBlockExpression bodyExpression = functionLiteral.getBodyExpression();
assert bodyExpression != null;
JetScope functionInnerScope =
FunctionDescriptorUtil.getFunctionInnerScope(
context.scope, functionDescriptor, context.trace);
JetTypeReference returnTypeRef = functionLiteral.getReturnTypeRef();
JetType declaredReturnType = null;
if (returnTypeRef != null) {
declaredReturnType =
context
.expressionTypingServices
.getTypeResolver()
.resolveType(context.scope, returnTypeRef, context.trace, true);
// This is needed for ControlStructureTypingVisitor#visitReturnExpression() to properly
// type-check returned expressions
functionDescriptor.setReturnType(declaredReturnType);
if (expectedReturnType != null) {
if (!JetTypeChecker.INSTANCE.isSubtypeOf(declaredReturnType, expectedReturnType)) {
context.trace.report(EXPECTED_RETURN_TYPE_MISMATCH.on(returnTypeRef, expectedReturnType));
}
}
}
// Type-check the body
ExpressionTypingContext newContext =
context
.replaceScope(functionInnerScope)
.replaceExpectedType(
declaredReturnType != null
? declaredReturnType
: (expectedReturnType != null ? expectedReturnType : NO_EXPECTED_TYPE));
JetType typeOfBodyExpression =
context
.expressionTypingServices
.getBlockReturnedType(bodyExpression, COERCION_TO_UNIT, newContext)
.getType();
List<JetType> returnedExpressionTypes =
Lists.newArrayList(
getTypesOfLocallyReturnedExpressions(
functionLiteral, context.trace, collectReturns(bodyExpression)));
ContainerUtil.addIfNotNull(returnedExpressionTypes, typeOfBodyExpression);
if (declaredReturnType != null) return declaredReturnType;
if (returnedExpressionTypes.isEmpty()) return null;
return CommonSupertypes.commonSupertype(returnedExpressionTypes);
}
@Override
public JetType visitFunctionLiteralExpression(
JetFunctionLiteralExpression expression, ExpressionTypingContext context) {
JetFunctionLiteral functionLiteral = expression.getFunctionLiteral();
JetBlockExpression bodyExpression = functionLiteral.getBodyExpression();
if (bodyExpression == null) return null;
JetType expectedType = context.expectedType;
boolean functionTypeExpected =
expectedType != TypeUtils.NO_EXPECTED_TYPE
&& JetStandardClasses.isFunctionType(expectedType);
NamedFunctionDescriptorImpl functionDescriptor =
createFunctionDescriptor(expression, context, functionTypeExpected);
List<JetType> parameterTypes = Lists.newArrayList();
List<ValueParameterDescriptor> valueParameters = functionDescriptor.getValueParameters();
for (ValueParameterDescriptor valueParameter : valueParameters) {
parameterTypes.add(valueParameter.getOutType());
}
ReceiverDescriptor receiverParameter = functionDescriptor.getReceiverParameter();
JetType receiver = receiverParameter != NO_RECEIVER ? receiverParameter.getType() : null;
JetType returnType = TypeUtils.NO_EXPECTED_TYPE;
JetScope functionInnerScope =
FunctionDescriptorUtil.getFunctionInnerScope(
context.scope, functionDescriptor, context.trace);
JetTypeReference returnTypeRef = functionLiteral.getReturnTypeRef();
if (returnTypeRef != null) {
returnType = context.getTypeResolver().resolveType(context.scope, returnTypeRef);
context
.getServices()
.checkFunctionReturnType(
expression,
context
.replaceScope(functionInnerScope)
.replaceExpectedType(returnType)
.replaceExpectedReturnType(returnType)
.replaceDataFlowInfo(context.dataFlowInfo));
} else {
if (functionTypeExpected) {
returnType = JetStandardClasses.getReturnTypeFromFunctionType(expectedType);
}
returnType =
context
.getServices()
.getBlockReturnedType(
functionInnerScope,
bodyExpression,
CoercionStrategy.COERCION_TO_UNIT,
context.replaceExpectedType(returnType).replaceExpectedReturnType(returnType));
}
JetType safeReturnType =
returnType == null ? ErrorUtils.createErrorType("<return type>") : returnType;
functionDescriptor.setReturnType(safeReturnType);
boolean hasDeclaredValueParameters = functionLiteral.getValueParameterList() != null;
if (!hasDeclaredValueParameters && functionTypeExpected) {
JetType expectedReturnType = JetStandardClasses.getReturnTypeFromFunctionType(expectedType);
if (JetStandardClasses.isUnit(expectedReturnType)) {
functionDescriptor.setReturnType(JetStandardClasses.getUnitType());
return DataFlowUtils.checkType(
JetStandardClasses.getFunctionType(
Collections.<AnnotationDescriptor>emptyList(),
receiver,
parameterTypes,
JetStandardClasses.getUnitType()),
expression,
context);
}
}
return DataFlowUtils.checkType(
JetStandardClasses.getFunctionType(
Collections.<AnnotationDescriptor>emptyList(),
receiver,
parameterTypes,
safeReturnType),
expression,
context);
}
@NotNull
/*package*/ OverloadResolutionResultsImpl<FunctionDescriptor> resolveFunctionCall(
@NotNull BasicCallResolutionContext context) {
ProgressIndicatorProvider.checkCanceled();
List<ResolutionTask<CallableDescriptor, FunctionDescriptor>> prioritizedTasks;
JetExpression calleeExpression = context.call.getCalleeExpression();
JetReferenceExpression functionReference;
if (calleeExpression instanceof JetSimpleNameExpression) {
JetSimpleNameExpression expression = (JetSimpleNameExpression) calleeExpression;
functionReference = expression;
ExpressionTypingUtils.checkCapturingInClosure(expression, context.trace, context.scope);
Name name = expression.getReferencedNameAsName();
prioritizedTasks =
TaskPrioritizer.<CallableDescriptor, FunctionDescriptor>computePrioritizedTasks(
context,
name,
functionReference,
CallableDescriptorCollectors.FUNCTIONS_AND_VARIABLES);
ResolutionTask.DescriptorCheckStrategy abstractConstructorCheck =
new ResolutionTask.DescriptorCheckStrategy() {
@Override
public <D extends CallableDescriptor> boolean performAdvancedChecks(
D descriptor, BindingTrace trace, TracingStrategy tracing) {
if (descriptor instanceof ConstructorDescriptor) {
Modality modality =
((ConstructorDescriptor) descriptor).getContainingDeclaration().getModality();
if (modality == Modality.ABSTRACT) {
tracing.instantiationOfAbstractClass(trace);
return false;
}
}
return true;
}
};
for (ResolutionTask task : prioritizedTasks) {
task.setCheckingStrategy(abstractConstructorCheck);
}
} else {
JetValueArgumentList valueArgumentList = context.call.getValueArgumentList();
PsiElement reportAbsenceOn =
valueArgumentList == null ? context.call.getCallElement() : valueArgumentList;
if (calleeExpression instanceof JetConstructorCalleeExpression) {
assert !context.call.getExplicitReceiver().exists();
JetConstructorCalleeExpression expression =
(JetConstructorCalleeExpression) calleeExpression;
functionReference = expression.getConstructorReferenceExpression();
if (functionReference == null) {
return checkArgumentTypesAndFail(context); // No type there
}
JetTypeReference typeReference = expression.getTypeReference();
assert typeReference != null;
JetType constructedType =
typeResolver.resolveType(context.scope, typeReference, context.trace, true);
if (constructedType.isError()) {
return checkArgumentTypesAndFail(context);
}
DeclarationDescriptor declarationDescriptor =
constructedType.getConstructor().getDeclarationDescriptor();
if (declarationDescriptor instanceof ClassDescriptor) {
ClassDescriptor classDescriptor = (ClassDescriptor) declarationDescriptor;
Collection<ConstructorDescriptor> constructors = classDescriptor.getConstructors();
if (constructors.isEmpty()) {
context.trace.report(NO_CONSTRUCTOR.on(reportAbsenceOn));
return checkArgumentTypesAndFail(context);
}
Collection<ResolutionCandidate<CallableDescriptor>> candidates =
TaskPrioritizer.<CallableDescriptor>convertWithImpliedThis(
context.scope,
Collections.<ReceiverValue>singletonList(NO_RECEIVER),
constructors);
prioritizedTasks =
TaskPrioritizer
.<CallableDescriptor, FunctionDescriptor>computePrioritizedTasksFromCandidates(
context, functionReference, candidates, null);
} else {
context.trace.report(NOT_A_CLASS.on(calleeExpression));
return checkArgumentTypesAndFail(context);
}
} else if (calleeExpression instanceof JetThisReferenceExpression) {
functionReference = (JetThisReferenceExpression) calleeExpression;
DeclarationDescriptor containingDeclaration = context.scope.getContainingDeclaration();
if (containingDeclaration instanceof ConstructorDescriptor) {
containingDeclaration = containingDeclaration.getContainingDeclaration();
}
assert containingDeclaration instanceof ClassDescriptor;
ClassDescriptor classDescriptor = (ClassDescriptor) containingDeclaration;
Collection<ConstructorDescriptor> constructors = classDescriptor.getConstructors();
if (constructors.isEmpty()) {
context.trace.report(NO_CONSTRUCTOR.on(reportAbsenceOn));
return checkArgumentTypesAndFail(context);
}
List<ResolutionCandidate<CallableDescriptor>> candidates =
ResolutionCandidate.<CallableDescriptor>convertCollection(
constructors, JetPsiUtil.isSafeCall(context.call));
prioritizedTasks =
Collections.singletonList(
new ResolutionTask<CallableDescriptor, FunctionDescriptor>(
candidates, functionReference, context)); // !! DataFlowInfo.EMPTY
} else if (calleeExpression != null) {
// Here we handle the case where the callee expression must be something of type function,
// e.g. (foo.bar())(1, 2)
JetType calleeType =
expressionTypingServices.safeGetType(
context.scope,
calleeExpression,
NO_EXPECTED_TYPE,
context.dataFlowInfo,
context
.trace); // We are actually expecting a function, but there seems to be no easy
// way of expressing this
if (!KotlinBuiltIns.getInstance().isFunctionOrExtensionFunctionType(calleeType)) {
// checkTypesWithNoCallee(trace, scope, call);
if (!calleeType.isError()) {
context.trace.report(CALLEE_NOT_A_FUNCTION.on(calleeExpression, calleeType));
}
return checkArgumentTypesAndFail(context);
}
FunctionDescriptorImpl functionDescriptor =
new ExpressionAsFunctionDescriptor(
context.scope.getContainingDeclaration(),
Name.special("<for expression " + calleeExpression.getText() + ">"),
calleeExpression);
FunctionDescriptorUtil.initializeFromFunctionType(
functionDescriptor,
calleeType,
NO_RECEIVER_PARAMETER,
Modality.FINAL,
Visibilities.LOCAL);
ResolutionCandidate<CallableDescriptor> resolutionCandidate =
ResolutionCandidate.<CallableDescriptor>create(
functionDescriptor, JetPsiUtil.isSafeCall(context.call));
resolutionCandidate.setReceiverArgument(context.call.getExplicitReceiver());
resolutionCandidate.setExplicitReceiverKind(ExplicitReceiverKind.RECEIVER_ARGUMENT);
// strictly speaking, this is a hack:
// we need to pass a reference, but there's no reference in the PSI,
// so we wrap what we have into a fake reference and pass it on (unwrap on the other end)
functionReference = new JetFakeReference(calleeExpression);
prioritizedTasks =
Collections.singletonList(
new ResolutionTask<CallableDescriptor, FunctionDescriptor>(
Collections.singleton(resolutionCandidate), functionReference, context));
} else {
// checkTypesWithNoCallee(trace, scope, call);
return checkArgumentTypesAndFail(context);
}
}
return doResolveCallOrGetCachedResults(
ResolutionResultsCache.FUNCTION_MEMBER_TYPE,
context,
prioritizedTasks,
CallTransformer.FUNCTION_CALL_TRANSFORMER,
functionReference);
}