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/*
* Copyright 2010-2021 JetBrains s.r.o. and Kotlin Programming Language contributors.
* Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
*/
package org.jetbrains.kotlin.resolve.calls
import com.intellij.lang.ASTNode
import com.intellij.openapi.util.ThrowableComputable
import com.intellij.psi.PsiElement
import com.intellij.psi.util.PsiTreeUtil
import com.intellij.util.AstLoadingFilter
import org.jetbrains.kotlin.builtins.KotlinBuiltIns
import org.jetbrains.kotlin.config.LanguageFeature
import org.jetbrains.kotlin.config.LanguageVersionSettings
import org.jetbrains.kotlin.descriptors.ConstructorDescriptor
import org.jetbrains.kotlin.descriptors.FunctionDescriptor
import org.jetbrains.kotlin.descriptors.VariableDescriptor
import org.jetbrains.kotlin.diagnostics.Errors.*
import org.jetbrains.kotlin.psi.*
import org.jetbrains.kotlin.psi.psiUtil.getParentOfType
import org.jetbrains.kotlin.resolve.*
import org.jetbrains.kotlin.resolve.bindingContextUtil.recordDataFlowInfo
import org.jetbrains.kotlin.resolve.bindingContextUtil.recordScope
import org.jetbrains.kotlin.resolve.calls.util.ResolveArgumentsMode
import org.jetbrains.kotlin.resolve.calls.util.getCalleeExpressionIfAny
import org.jetbrains.kotlin.resolve.calls.util.getResolvedCall
import org.jetbrains.kotlin.resolve.calls.context.BasicCallResolutionContext
import org.jetbrains.kotlin.resolve.calls.context.CheckArgumentTypesMode
import org.jetbrains.kotlin.resolve.calls.context.ContextDependency.INDEPENDENT
import org.jetbrains.kotlin.resolve.calls.context.ResolutionContext
import org.jetbrains.kotlin.resolve.calls.context.TemporaryTraceAndCache
import org.jetbrains.kotlin.resolve.calls.model.DataFlowInfoForArgumentsImpl
import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
import org.jetbrains.kotlin.resolve.calls.model.ResolvedCallImpl
import org.jetbrains.kotlin.resolve.calls.results.OverloadResolutionResults
import org.jetbrains.kotlin.resolve.calls.results.OverloadResolutionResults.Code.CANDIDATES_WITH_WRONG_RECEIVER
import org.jetbrains.kotlin.resolve.calls.results.OverloadResolutionResults.Code.NAME_NOT_FOUND
import org.jetbrains.kotlin.resolve.calls.results.OverloadResolutionResultsUtil
import org.jetbrains.kotlin.resolve.calls.results.ResolutionStatus
import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowInfo
import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValue
import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactory
import org.jetbrains.kotlin.resolve.calls.util.CallMaker
import org.jetbrains.kotlin.resolve.calls.util.FakeCallableDescriptorForObject
import org.jetbrains.kotlin.resolve.constants.evaluate.ConstantExpressionEvaluator
import org.jetbrains.kotlin.resolve.scopes.receivers.*
import org.jetbrains.kotlin.types.*
import org.jetbrains.kotlin.types.error.ErrorUtils
import org.jetbrains.kotlin.types.TypeUtils.NO_EXPECTED_TYPE
import org.jetbrains.kotlin.types.checker.KotlinTypeRefiner
import org.jetbrains.kotlin.types.error.ErrorTypeKind
import org.jetbrains.kotlin.types.expressions.DataFlowAnalyzer
import org.jetbrains.kotlin.types.expressions.ExpressionTypingContext
import org.jetbrains.kotlin.types.expressions.ExpressionTypingServices
import org.jetbrains.kotlin.types.expressions.KotlinTypeInfo
import org.jetbrains.kotlin.types.expressions.typeInfoFactory.createTypeInfo
import org.jetbrains.kotlin.types.expressions.typeInfoFactory.noTypeInfo
import javax.inject.Inject
class CallExpressionResolver(
private val callResolver: CallResolver,
private val constantExpressionEvaluator: ConstantExpressionEvaluator,
private val argumentTypeResolver: ArgumentTypeResolver,
private val dataFlowAnalyzer: DataFlowAnalyzer,
private val builtIns: KotlinBuiltIns,
private val qualifiedExpressionResolver: QualifiedExpressionResolver,
private val languageVersionSettings: LanguageVersionSettings,
private val dataFlowValueFactory: DataFlowValueFactory,
private val kotlinTypeRefiner: KotlinTypeRefiner
) {
private lateinit var expressionTypingServices: ExpressionTypingServices
// component dependency cycle
@Inject
fun setExpressionTypingServices(expressionTypingServices: ExpressionTypingServices) {
this.expressionTypingServices = expressionTypingServices
}
private fun getResolvedCallForFunction(
call: Call,
context: ResolutionContext<*>,
checkArguments: CheckArgumentTypesMode,
initialDataFlowInfoForArguments: DataFlowInfo
): Pair?> {
val results = callResolver.resolveFunctionCall(
BasicCallResolutionContext.create(
context, call, checkArguments, DataFlowInfoForArgumentsImpl(initialDataFlowInfoForArguments, call)
)
)
return if (!results.isNothing)
Pair(true, OverloadResolutionResultsUtil.getResultingCall(results, context))
else
Pair(false, null)
}
private fun getVariableType(
nameExpression: KtSimpleNameExpression, receiver: Receiver?,
callOperationNode: ASTNode?, context: ExpressionTypingContext
): Pair {
val temporaryForVariable = TemporaryTraceAndCache.create(
context, "trace to resolve as local variable or property", nameExpression
)
val call = CallMaker.makePropertyCall(receiver, callOperationNode, nameExpression)
val contextForVariable = BasicCallResolutionContext.create(
context.replaceTraceAndCache(temporaryForVariable),
call, CheckArgumentTypesMode.CHECK_VALUE_ARGUMENTS
)
val resolutionResult = callResolver.resolveSimpleProperty(contextForVariable)
// if the expression is a receiver in a qualified expression, it should be resolved after the selector is resolved
val isLHSOfDot = KtPsiUtil.isLHSOfDot(nameExpression)
if (!resolutionResult.isNothing && resolutionResult.resultCode != CANDIDATES_WITH_WRONG_RECEIVER) {
val isQualifier = isLHSOfDot &&
resolutionResult.isSingleResult &&
resolutionResult.resultingDescriptor is FakeCallableDescriptorForObject
if (!isQualifier) {
temporaryForVariable.commit()
return Pair(true, if (resolutionResult.isSingleResult) resolutionResult.resultingDescriptor.returnType else null)
}
}
temporaryForVariable.commit()
return Pair(
!resolutionResult.isNothing,
if (resolutionResult.isSingleResult) resolutionResult.resultingDescriptor.returnType else null
)
}
fun getSimpleNameExpressionTypeInfo(
nameExpression: KtSimpleNameExpression, receiver: Receiver?,
callOperationNode: ASTNode?, context: ExpressionTypingContext
) = getSimpleNameExpressionTypeInfo(nameExpression, receiver, callOperationNode, context, context.dataFlowInfo)
private fun getSimpleNameExpressionTypeInfo(
nameExpression: KtSimpleNameExpression, receiver: Receiver?,
callOperationNode: ASTNode?, context: ExpressionTypingContext,
initialDataFlowInfoForArguments: DataFlowInfo
): KotlinTypeInfo {
val temporaryForVariable = TemporaryTraceAndCache.create(
context, "trace to resolve as variable", nameExpression
)
val (notNothing, type) = getVariableType(
nameExpression, receiver, callOperationNode,
context.replaceTraceAndCache(temporaryForVariable)
)
if (notNothing) {
temporaryForVariable.commit()
return createTypeInfo(type, initialDataFlowInfoForArguments)
}
val call = CallMaker.makeCall(nameExpression, receiver, callOperationNode, nameExpression, emptyList())
val temporaryForFunction = TemporaryTraceAndCache.create(
context, "trace to resolve as function", nameExpression
)
val newContext = context.replaceTraceAndCache(temporaryForFunction)
val (resolveResult, resolvedCall) = getResolvedCallForFunction(
call, newContext, CheckArgumentTypesMode.CHECK_VALUE_ARGUMENTS, initialDataFlowInfoForArguments
)
if (resolveResult) {
val functionDescriptor = resolvedCall?.resultingDescriptor
if (functionDescriptor !is ConstructorDescriptor) {
temporaryForFunction.commit()
val hasValueParameters = functionDescriptor == null || functionDescriptor.valueParameters.size > 0
context.trace.report(FUNCTION_CALL_EXPECTED.on(nameExpression, nameExpression, hasValueParameters))
return createTypeInfo(functionDescriptor?.returnType, context)
}
}
val temporaryForQualifier = TemporaryTraceAndCache.create(context, "trace to resolve as qualifier", nameExpression)
val contextForQualifier = context.replaceTraceAndCache(temporaryForQualifier)
qualifiedExpressionResolver.resolveNameExpressionAsQualifierForDiagnostics(nameExpression, receiver, contextForQualifier)?.let {
resolveQualifierAsStandaloneExpression(it, contextForQualifier)
temporaryForQualifier.commit()
} ?: temporaryForVariable.commit()
return noTypeInfo(context)
}
fun getCallExpressionTypeInfo(
callExpression: KtCallExpression,
context: ExpressionTypingContext
): KotlinTypeInfo {
val typeInfo = getCallExpressionTypeInfoWithoutFinalTypeCheck(
callExpression, null, null, context, context.dataFlowInfo
)
if (context.contextDependency == INDEPENDENT) {
dataFlowAnalyzer.checkType(typeInfo.type, callExpression, context)
}
return typeInfo
}
/**
* Visits a call expression and its arguments.
* Determines the result type and data flow information after the call.
*/
private fun getCallExpressionTypeInfoWithoutFinalTypeCheck(
callExpression: KtCallExpression, receiver: Receiver?,
callOperationNode: ASTNode?, context: ExpressionTypingContext,
initialDataFlowInfoForArguments: DataFlowInfo
): KotlinTypeInfo {
val call = CallMaker.makeCall(receiver, callOperationNode, callExpression)
val temporaryForFunction = TemporaryTraceAndCache.create(
context, "trace to resolve as function call", callExpression
)
val (resolveResult, resolvedCall) = getResolvedCallForFunction(
call,
context.replaceTraceAndCache(temporaryForFunction),
CheckArgumentTypesMode.CHECK_VALUE_ARGUMENTS,
initialDataFlowInfoForArguments
)
if (resolveResult) {
val functionDescriptor = resolvedCall?.resultingDescriptor
temporaryForFunction.commit()
if (callExpression.valueArgumentList == null && callExpression.lambdaArguments.isEmpty()) {
// there are only type arguments
val hasValueParameters = functionDescriptor == null || functionDescriptor.valueParameters.size > 0
context.trace.report(FUNCTION_CALL_EXPECTED.on(callExpression, callExpression, hasValueParameters))
}
if (functionDescriptor == null) {
return noTypeInfo(context)
}
if (functionDescriptor is ConstructorDescriptor) {
val constructedClass = functionDescriptor.constructedClass
if (DescriptorUtils.isAnnotationClass(constructedClass) && !canInstantiateAnnotationClass(callExpression, context.trace)) {
val supported = context.languageVersionSettings.supportsFeature(LanguageFeature.InstantiationOfAnnotationClasses)
if (!supported) context.trace.report(ANNOTATION_CLASS_CONSTRUCTOR_CALL.on(callExpression))
}
if (DescriptorUtils.isEnumClass(constructedClass)) {
context.trace.report(ENUM_CLASS_CONSTRUCTOR_CALL.on(callExpression))
}
if (DescriptorUtils.isSealedClass(constructedClass)) {
context.trace.report(SEALED_CLASS_CONSTRUCTOR_CALL.on(callExpression))
}
}
val type = functionDescriptor.returnType
// Extracting jump out possible and jump point flow info from arguments, if any
val arguments = callExpression.valueArguments
val resultFlowInfo = resolvedCall.dataFlowInfoForArguments.resultInfo
var jumpFlowInfo = resultFlowInfo
var jumpOutPossible = false
for (argument in arguments) {
val argTypeInfo = context.trace.get(BindingContext.EXPRESSION_TYPE_INFO, argument.getArgumentExpression())
if (argTypeInfo != null && argTypeInfo.jumpOutPossible) {
jumpOutPossible = true
jumpFlowInfo = argTypeInfo.jumpFlowInfo
break
}
}
return createTypeInfo(type, resultFlowInfo, jumpOutPossible, jumpFlowInfo)
}
val calleeExpression = callExpression.calleeExpression
if (calleeExpression is KtSimpleNameExpression && callExpression.typeArgumentList == null) {
val temporaryForVariable = TemporaryTraceAndCache.create(
context, "trace to resolve as variable with 'invoke' call", callExpression
)
val (notNothing, type) = getVariableType(
calleeExpression, receiver, callOperationNode,
context.replaceTraceAndCache(temporaryForVariable)
)
val qualifier = temporaryForVariable.trace.get(BindingContext.QUALIFIER, calleeExpression)
if (notNothing && (qualifier == null || qualifier !is PackageQualifier)) {
// mark property call as unsuccessful to avoid exceptions
callExpression.getResolvedCall(temporaryForVariable.trace.bindingContext).let {
(it as? ResolvedCallImpl)?.addStatus(ResolutionStatus.OTHER_ERROR)
}
temporaryForVariable.commit()
context.trace.report(
FUNCTION_EXPECTED.on(
calleeExpression, calleeExpression,
type ?: ErrorUtils.createErrorType(ErrorTypeKind.ERROR_EXPECTED_TYPE)
)
)
argumentTypeResolver.analyzeArgumentsAndRecordTypes(
BasicCallResolutionContext.create(
context, call, CheckArgumentTypesMode.CHECK_VALUE_ARGUMENTS,
DataFlowInfoForArgumentsImpl(initialDataFlowInfoForArguments, call)
),
ResolveArgumentsMode.RESOLVE_FUNCTION_ARGUMENTS
)
return noTypeInfo(context)
}
}
temporaryForFunction.commit()
return noTypeInfo(context)
}
private fun KtQualifiedExpression.elementChain(context: ExpressionTypingContext) =
qualifiedExpressionResolver.resolveQualifierInExpressionAndUnroll(this, context) { nameExpression ->
val temporaryTraceAndCache =
TemporaryTraceAndCache.create(context, "trace to resolve as local variable or property", nameExpression)
val resolutionResult = resolveSimpleName(context, nameExpression, temporaryTraceAndCache)
if (resolutionResult.isSingleResult && resolutionResult.resultingDescriptor is FakeCallableDescriptorForObject) {
false
} else when (resolutionResult.resultCode) {
NAME_NOT_FOUND, CANDIDATES_WITH_WRONG_RECEIVER -> false
else -> {
val newInferenceEnabled = context.languageVersionSettings.supportsFeature(LanguageFeature.NewInference)
val success = !newInferenceEnabled || resolutionResult.isSuccess
if (newInferenceEnabled && success) {
temporaryTraceAndCache.commit()
}
success
}
}
}
private fun resolveSimpleName(
context: ExpressionTypingContext, expression: KtSimpleNameExpression, traceAndCache: TemporaryTraceAndCache
): OverloadResolutionResults {
val call = CallMaker.makePropertyCall(null, null, expression)
val contextForVariable = BasicCallResolutionContext.create(
context.replaceTraceAndCache(traceAndCache), call, CheckArgumentTypesMode.CHECK_VALUE_ARGUMENTS
)
return callResolver.resolveSimpleProperty(contextForVariable)
}
private fun getUnsafeSelectorTypeInfo(
receiver: Receiver,
callOperationNode: ASTNode?,
selectorExpression: KtExpression?,
context: ExpressionTypingContext,
initialDataFlowInfoForArguments: DataFlowInfo
): KotlinTypeInfo = when (selectorExpression) {
is KtCallExpression -> getCallExpressionTypeInfoWithoutFinalTypeCheck(
selectorExpression, receiver, callOperationNode, context, initialDataFlowInfoForArguments
)
is KtSimpleNameExpression -> getSimpleNameExpressionTypeInfo(
selectorExpression, receiver, callOperationNode, context, initialDataFlowInfoForArguments
)
is KtExpression -> {
expressionTypingServices.getTypeInfo(selectorExpression, context)
context.trace.report(ILLEGAL_SELECTOR.on(selectorExpression))
noTypeInfo(context)
}
else /*null*/ -> noTypeInfo(context)
}
private fun getSafeOrUnsafeSelectorTypeInfo(receiver: Receiver, element: CallExpressionElement, context: ExpressionTypingContext):
KotlinTypeInfo {
var initialDataFlowInfoForArguments = context.dataFlowInfo
val receiverDataFlowValue = (receiver as? ReceiverValue)?.let { dataFlowValueFactory.createDataFlowValue(it, context) }
val receiverCanBeNull = receiverDataFlowValue != null && initialDataFlowInfoForArguments.getStableNullability(receiverDataFlowValue).canBeNull()
val shouldNullifySafeCallType =
receiverCanBeNull || context.languageVersionSettings.supportsFeature(LanguageFeature.SafeCallsAreAlwaysNullable)
val callOperationNode = AstLoadingFilter.forceAllowTreeLoading(element.qualified.containingFile, ThrowableComputable {
element.node
})
if (receiverDataFlowValue != null && element.safe) {
// Additional "receiver != null" information should be applied if we consider a safe call
if (shouldNullifySafeCallType) {
initialDataFlowInfoForArguments = initialDataFlowInfoForArguments.disequate(
receiverDataFlowValue, DataFlowValue.nullValue(builtIns), languageVersionSettings
)
}
if (!receiverCanBeNull) {
reportUnnecessarySafeCall(
context.trace,
receiver.type,
element.qualified,
callOperationNode,
receiver,
context.languageVersionSettings
)
}
}
val selector = element.selector
@OptIn(TypeRefinement::class)
var selectorTypeInfo =
getUnsafeSelectorTypeInfo(receiver, callOperationNode, selector, context, initialDataFlowInfoForArguments)
.run {
val type = type ?: return@run this
replaceType(kotlinTypeRefiner.refineType(type))
}
if (receiver is Qualifier) {
resolveDeferredReceiverInQualifiedExpression(receiver, selector, context)
}
val selectorType = selectorTypeInfo.type
if (selectorType != null) {
if (element.safe && shouldNullifySafeCallType) {
selectorTypeInfo = selectorTypeInfo.replaceType(TypeUtils.makeNullable(selectorType))
}
// TODO : this is suspicious: remove this code?
if (selector != null) {
context.trace.recordType(selector, selectorTypeInfo.type)
}
}
return selectorTypeInfo
}
private fun checkSelectorTypeInfo(qualified: KtQualifiedExpression, selectorTypeInfo: KotlinTypeInfo, context: ExpressionTypingContext):
KotlinTypeInfo {
checkNestedClassAccess(qualified, context)
val value = constantExpressionEvaluator.evaluateExpression(qualified, context.trace, context.expectedType)
return if (value != null && value.isPure) {
dataFlowAnalyzer.createCompileTimeConstantTypeInfo(value, qualified, context)
} else {
if (context.contextDependency == INDEPENDENT) {
dataFlowAnalyzer.checkType(selectorTypeInfo.type, qualified, context)
}
selectorTypeInfo
}
}
private fun recordResultTypeInfo(qualified: KtQualifiedExpression, resultTypeInfo: KotlinTypeInfo, context: ExpressionTypingContext) {
val trace = context.trace
if (trace.get(BindingContext.PROCESSED, qualified) != true) {
// Store type information (to prevent problems in call completer)
trace.record(BindingContext.PROCESSED, qualified)
trace.record(BindingContext.EXPRESSION_TYPE_INFO, qualified, resultTypeInfo)
// save scope before analyze and fix debugger: see CodeFragmentAnalyzer.correctContextForExpression
trace.recordScope(context.scope, qualified)
context.replaceDataFlowInfo(resultTypeInfo.dataFlowInfo).recordDataFlowInfo(qualified)
}
}
/**
* Visits a qualified expression like x.y or x?.z controlling data flow information changes.
* @return qualified expression type together with data flow information
*/
fun getQualifiedExpressionTypeInfo(expression: KtQualifiedExpression, context: ExpressionTypingContext): KotlinTypeInfo {
val currentContext = context.replaceExpectedType(NO_EXPECTED_TYPE).replaceContextDependency(INDEPENDENT)
val trace = currentContext.trace
val elementChain = expression.elementChain(currentContext)
val firstReceiver = elementChain.first().receiver
var receiverTypeInfo = when (trace.get(BindingContext.QUALIFIER, firstReceiver)) {
null -> expressionTypingServices.getTypeInfo(firstReceiver, currentContext)
else -> KotlinTypeInfo(null, currentContext.dataFlowInfo)
}
var resultTypeInfo = receiverTypeInfo
var allUnsafe = true
// Branch point: right before first safe call
var branchPointDataFlowInfo = receiverTypeInfo.dataFlowInfo
for (element in elementChain) {
val receiverType = receiverTypeInfo.type
?: ErrorUtils.createErrorType(
ErrorTypeKind.ERROR_RECEIVER_TYPE,
when (val receiver = element.receiver) {
is KtNameReferenceExpression -> receiver.getReferencedName()
else -> receiver.text
}
)
val receiver = trace.get(BindingContext.QUALIFIER, element.receiver)
?: ExpressionReceiver.create(element.receiver, receiverType, trace.bindingContext)
val qualifiedExpression = element.qualified
val lastStage = qualifiedExpression === expression
// Drop NO_EXPECTED_TYPE / INDEPENDENT at last stage
val contextForSelector = (if (lastStage) context else currentContext).replaceDataFlowInfo(
if (receiver is ReceiverValue && TypeUtils.isNullableType(receiver.type) && !element.safe) {
// Call with nullable receiver: take data flow info from branch point
branchPointDataFlowInfo
} else {
// Take data flow info from the current receiver
receiverTypeInfo.dataFlowInfo
}
)
val selectorTypeInfo = getSafeOrUnsafeSelectorTypeInfo(receiver, element, contextForSelector)
// if we have only dots and not ?. move branch point further
allUnsafe = allUnsafe && !element.safe
if (allUnsafe) {
branchPointDataFlowInfo = selectorTypeInfo.dataFlowInfo
}
resultTypeInfo = checkSelectorTypeInfo(qualifiedExpression, selectorTypeInfo, contextForSelector).replaceDataFlowInfo(
branchPointDataFlowInfo
)
if (!lastStage) {
recordResultTypeInfo(qualifiedExpression, resultTypeInfo, contextForSelector)
}
// For the next stage, if any, current stage selector is the receiver!
receiverTypeInfo = selectorTypeInfo
}
return resultTypeInfo
}
private fun resolveDeferredReceiverInQualifiedExpression(
qualifier: Qualifier,
selectorExpression: KtExpression?,
context: ExpressionTypingContext
) {
val calleeExpression = KtPsiUtil.deparenthesize(selectorExpression.getCalleeExpressionIfAny())
val selectorDescriptor = (calleeExpression as? KtReferenceExpression)?.let {
context.trace.get(BindingContext.REFERENCE_TARGET, it)
}
resolveQualifierAsReceiverInExpression(qualifier, selectorDescriptor, context)
}
companion object {
fun canInstantiateAnnotationClass(expression: KtCallExpression, trace: BindingTrace): Boolean {
//noinspection unchecked
var parent: PsiElement? = PsiTreeUtil.getParentOfType(expression, KtValueArgument::class.java, KtParameter::class.java)
if (parent is KtValueArgument) {
if (parent.getParentOfType(true) != null) {
return true
}
parent = parent.getParentOfType(true)
if (parent != null) {
return isUnderAnnotationClassDeclaration(trace, parent)
}
} else if (parent is KtParameter) {
return isUnderAnnotationClassDeclaration(trace, parent)
}
return false
}
private fun isUnderAnnotationClassDeclaration(trace: BindingTrace, parent: PsiElement) =
parent.getParentOfType(true)?.let {
DescriptorUtils.isAnnotationClass(trace.get(BindingContext.DECLARATION_TO_DESCRIPTOR, it))
} ?: false
fun reportUnnecessarySafeCall(
trace: BindingTrace,
type: KotlinType,
callElement: KtQualifiedExpression,
callOperationNode: ASTNode,
explicitReceiver: Receiver?,
languageVersionSettings: LanguageVersionSettings
) {
if (explicitReceiver is ExpressionReceiver && explicitReceiver.expression is KtSuperExpression) {
trace.report(UNEXPECTED_SAFE_CALL.on(callOperationNode.psi))
} else if (!type.isError) {
trace.report(UNNECESSARY_SAFE_CALL.on(callOperationNode.psi, type))
if (!languageVersionSettings.supportsFeature(LanguageFeature.SafeCallsAreAlwaysNullable)) {
trace.report(SAFE_CALL_WILL_CHANGE_NULLABILITY.on(callElement))
}
}
}
private fun checkNestedClassAccess(
expression: KtQualifiedExpression,
context: ExpressionTypingContext
) {
val selectorExpression = expression.selectorExpression ?: return
// A.B - if B is a nested class accessed by outer class, 'A' and 'A.B' were marked as qualifiers
// a.B - if B is a nested class accessed by instance reference, 'a.B' was marked as a qualifier, but 'a' was not (it's an expression)
val expressionQualifier = context.trace.get(BindingContext.QUALIFIER, expression)
val receiverQualifier = context.trace.get(BindingContext.QUALIFIER, expression.receiverExpression)
if (receiverQualifier == null && expressionQualifier != null) {
assert(expressionQualifier is ClassifierQualifier) { "Only class can (package cannot) be accessed by instance reference: " + expressionQualifier }
val descriptor = (expressionQualifier as ClassifierQualifier).descriptor
context.trace.report(NESTED_CLASS_ACCESSED_VIA_INSTANCE_REFERENCE.on(selectorExpression, descriptor))
}
}
}
}