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org.jetbrains.kotlin.resolve.jvm.checkers.JavaNullabilityChecker.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2016 JetBrains s.r.o.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.jetbrains.kotlin.resolve.jvm.checkers
import org.jetbrains.kotlin.cfg.WhenChecker
import org.jetbrains.kotlin.config.LanguageFeature
import org.jetbrains.kotlin.descriptors.ReceiverParameterDescriptor
import org.jetbrains.kotlin.diagnostics.Errors
import org.jetbrains.kotlin.lexer.KtTokens
import org.jetbrains.kotlin.psi.KtBinaryExpression
import org.jetbrains.kotlin.psi.KtExpression
import org.jetbrains.kotlin.psi.KtPostfixExpression
import org.jetbrains.kotlin.psi.KtWhenExpression
import org.jetbrains.kotlin.resolve.BindingContext
import org.jetbrains.kotlin.resolve.calls.checkers.AdditionalTypeChecker
import org.jetbrains.kotlin.resolve.calls.context.CallResolutionContext
import org.jetbrains.kotlin.resolve.calls.context.ResolutionContext
import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowInfo
import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValue
import org.jetbrains.kotlin.resolve.calls.smartcasts.Nullability
import org.jetbrains.kotlin.resolve.jvm.diagnostics.ErrorsJvm
import org.jetbrains.kotlin.resolve.scopes.receivers.ExpressionReceiver
import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
import org.jetbrains.kotlin.types.*
import org.jetbrains.kotlin.types.checker.ClassicTypeCheckerContext
import org.jetbrains.kotlin.types.checker.KotlinTypeChecker
import org.jetbrains.kotlin.types.expressions.SenselessComparisonChecker
import org.jetbrains.kotlin.types.model.KotlinTypeMarker
import org.jetbrains.kotlin.types.typeUtil.contains
import org.jetbrains.kotlin.types.typeUtil.makeNotNullable
class JavaNullabilityChecker : AdditionalTypeChecker {
override fun checkType(
expression: KtExpression,
expressionType: KotlinType,
expressionTypeWithSmartCast: KotlinType,
c: ResolutionContext<*>
) {
val dataFlowValue by lazy(LazyThreadSafetyMode.NONE) {
c.dataFlowValueFactory.createDataFlowValue(expression, expressionType, c)
}
if (isWrongTypeParameterNullabilityForSubtyping(expressionType, c) { dataFlowValue }) {
c.trace.report(ErrorsJvm.NULLABLE_TYPE_PARAMETER_AGAINST_NOT_NULL_TYPE_PARAMETER.on(expression, expressionType))
}
doCheckType(
expressionType,
c.expectedType,
{ dataFlowValue },
c.dataFlowInfo
) { expectedType, actualType ->
c.trace.report(ErrorsJvm.NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS.on(expression, expectedType, actualType))
}
when (expression) {
is KtWhenExpression ->
if (expression.elseExpression == null) {
// Check for conditionally-exhaustive when on platform enums, see KT-6399
val subjectExpression = expression.subjectExpression ?: return
val type = c.trace.getType(subjectExpression) ?: return
if (type.isFlexible() && TypeUtils.isNullableType(type.asFlexibleType().upperBound)) {
val enumClassDescriptor = WhenChecker.getClassDescriptorOfTypeIfEnum(type) ?: return
val context = c.trace.bindingContext
if (WhenChecker.getEnumMissingCases(expression, context, enumClassDescriptor).isEmpty()
&& !WhenChecker.containsNullCase(expression, context)
) {
val subjectDataFlowValue = c.dataFlowValueFactory.createDataFlowValue(subjectExpression, type, c)
val dataFlowInfo = c.trace[BindingContext.EXPRESSION_TYPE_INFO, subjectExpression]?.dataFlowInfo
if (dataFlowInfo != null && !dataFlowInfo.getStableNullability(subjectDataFlowValue).canBeNull()) {
return
}
c.trace.report(ErrorsJvm.WHEN_ENUM_CAN_BE_NULL_IN_JAVA.on(expression.subjectExpression!!))
}
}
}
is KtPostfixExpression ->
if (expression.operationToken == KtTokens.EXCLEXCL) {
val baseExpression = expression.baseExpression ?: return
val baseExpressionType = c.trace.getType(baseExpression) ?: return
doIfNotNull(
baseExpressionType,
{ c.dataFlowValueFactory.createDataFlowValue(baseExpression, baseExpressionType, c) },
c
) {
c.trace.report(Errors.UNNECESSARY_NOT_NULL_ASSERTION.on(expression.operationReference, baseExpressionType))
}
}
is KtBinaryExpression ->
when (expression.operationToken) {
KtTokens.EQEQ,
KtTokens.EXCLEQ,
KtTokens.EQEQEQ,
KtTokens.EXCLEQEQEQ -> {
if (expression.left != null && expression.right != null) {
SenselessComparisonChecker.checkSenselessComparisonWithNull(
expression, expression.left!!, expression.right!!, c,
{ c.trace.getType(it) },
{ value ->
doIfNotNull(value.type, { value }, c) { Nullability.NOT_NULL } ?: Nullability.UNKNOWN
}
)
}
}
}
}
}
private fun isWrongTypeParameterNullabilityForSubtyping(
expressionType: KotlinType,
c: ResolutionContext<*>,
dataFlowValueForWholeExpression: () -> DataFlowValue
): Boolean {
if (c.languageVersionSettings.supportsFeature(LanguageFeature.ProhibitUsingNullableTypeParameterAgainstNotNullAnnotated)) return false
if (TypeUtils.noExpectedType(c.expectedType)) return false
var metWrongNullabilityInsideArguments = false
val typeContext: AbstractTypeCheckerContext = object : ClassicTypeCheckerContext(errorTypeEqualsToAnything = true) {
private var expectsTypeArgument = false
override fun customIsSubtypeOf(subType: KotlinTypeMarker, superType: KotlinTypeMarker): Boolean {
if (isNullableTypeAgainstNotNullTypeParameter(subType as KotlinType, superType as KotlinType)) {
// data flow value is only checked for top-level types
if (expectsTypeArgument || c.dataFlowInfo.getStableNullability(dataFlowValueForWholeExpression()) != Nullability.NOT_NULL) {
metWrongNullabilityInsideArguments = true
return false
}
}
if (!expectsTypeArgument) {
expectsTypeArgument = true
}
return true
}
}
AbstractTypeChecker.isSubtypeOf(typeContext, expressionType, c.expectedType)
return metWrongNullabilityInsideArguments
}
private fun isNullableTypeAgainstNotNullTypeParameter(
subType: KotlinType,
superType: KotlinType
): Boolean {
if (superType !is NotNullTypeVariable) return false
return !AbstractNullabilityChecker.isSubtypeOfAny(
ClassicTypeCheckerContext(errorTypeEqualsToAnything = true) as AbstractTypeCheckerContext,
subType
)
}
override fun checkReceiver(
receiverParameter: ReceiverParameterDescriptor,
receiverArgument: ReceiverValue,
safeAccess: Boolean,
c: CallResolutionContext<*>
) {
val dataFlowValue by lazy(LazyThreadSafetyMode.NONE) {
c.dataFlowValueFactory.createDataFlowValue(receiverArgument, c)
}
if (safeAccess) {
val safeAccessElement = c.call.callOperationNode?.psi ?: return
doIfNotNull(receiverArgument.type, { dataFlowValue }, c) {
c.trace.report(Errors.UNNECESSARY_SAFE_CALL.on(safeAccessElement, receiverArgument.type))
}
return
}
doCheckType(
receiverArgument.type,
receiverParameter.type,
{ dataFlowValue },
c.dataFlowInfo
) { expectedType, actualType ->
val receiverExpression = (receiverArgument as? ExpressionReceiver)?.expression
if (receiverExpression != null) {
c.trace.report(ErrorsJvm.RECEIVER_NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS.on(receiverExpression, actualType))
} else {
val reportOn = c.call.calleeExpression ?: c.call.callElement
c.trace.report(ErrorsJvm.NULLABILITY_MISMATCH_BASED_ON_JAVA_ANNOTATIONS.on(reportOn, expectedType, actualType))
}
}
}
private fun doCheckType(
expressionType: KotlinType,
expectedType: KotlinType,
expressionTypeDataFlowValue: () -> DataFlowValue,
dataFlowInfo: DataFlowInfo,
reportWarning: (expectedType: KotlinType, actualType: KotlinType) -> Unit
) {
if (TypeUtils.noExpectedType(expectedType)) return
val doesExpectedTypeContainsEnhancement = expectedType.contains { it is TypeWithEnhancement }
val doesExpressionTypeContainsEnhancement = expressionType.contains { it is TypeWithEnhancement }
if (!doesExpectedTypeContainsEnhancement && !doesExpressionTypeContainsEnhancement) return
val enhancedExpectedType = if (doesExpectedTypeContainsEnhancement) buildTypeWithEnhancement(expectedType) else expectedType
val enhancedExpressionType = enhanceExpressionTypeByDataFlowNullability(
if (doesExpressionTypeContainsEnhancement) buildTypeWithEnhancement(expressionType) else expressionType,
expressionTypeDataFlowValue,
dataFlowInfo
)
val isEnhancedExpectedTypeSubtypeOfExpressionType =
KotlinTypeChecker.DEFAULT.isSubtypeOf(enhancedExpressionType, enhancedExpectedType)
if (isEnhancedExpectedTypeSubtypeOfExpressionType) return
val isExpectedTypeSubtypeOfExpressionType = KotlinTypeChecker.DEFAULT.isSubtypeOf(expressionType, expectedType)
if (!isEnhancedExpectedTypeSubtypeOfExpressionType && isExpectedTypeSubtypeOfExpressionType) {
reportWarning(enhancedExpectedType, enhancedExpressionType)
}
}
private fun enhanceExpressionTypeByDataFlowNullability(
expressionType: KotlinType,
expressionTypeDataFlowValue: () -> DataFlowValue,
dataFlowInfo: DataFlowInfo,
): KotlinType {
val isNotNullByDataFlowInfo = dataFlowInfo.getStableNullability(expressionTypeDataFlowValue()) == Nullability.NOT_NULL
return if (expressionType.isNullable() && isNotNullByDataFlowInfo) expressionType.makeNotNullable() else expressionType
}
private fun doIfNotNull(
type: KotlinType,
dataFlowValue: () -> DataFlowValue,
c: ResolutionContext<*>,
body: () -> T
) = if (type.mustNotBeNull()?.isFromJava == true && c.dataFlowInfo.getStableNullability(dataFlowValue()).canBeNull()) {
body()
} else {
null
}
private fun enhanceTypeArguments(arguments: List) =
arguments.map { argument ->
// TODO: think about star projections with enhancement (e.g. came from Java: Foo<@NotNull ?>)
if (argument.isStarProjection) {
return@map argument
}
val argumentType = argument.type
val enhancedArgumentType = if (argumentType is TypeWithEnhancement) argumentType.enhancement else argumentType
val enhancedDeeplyArgumentType = buildTypeWithEnhancement(enhancedArgumentType)
argument.replaceType(enhancedDeeplyArgumentType)
}
fun buildTypeWithEnhancement(type: KotlinType): KotlinType {
val newArguments = enhanceTypeArguments(type.arguments)
val newArgumentsForUpperBound =
if (type is FlexibleType) {
enhanceTypeArguments(type.upperBound.arguments)
} else newArguments
val enhancedType = if (type is TypeWithEnhancement) type.enhancement else type
return enhancedType.replace(
newArguments = newArguments,
newArgumentsForUpperBound = newArgumentsForUpperBound
)
}
}
class EnhancedNullabilityInfo(val enhancedType: KotlinType, val isFromJava: Boolean) {
val isFromKotlin get() = !isFromJava
}
private fun KotlinType.enhancementFromKotlin() = EnhancedNullabilityInfo(this, isFromJava = false)
private fun TypeWithEnhancement.enhancementFromJava() = EnhancedNullabilityInfo(enhancement, isFromJava = true)
fun KotlinType.mustNotBeNull(): EnhancedNullabilityInfo? = when {
!isError && !isFlexible() && !TypeUtils.acceptsNullable(this) -> enhancementFromKotlin()
isFlexible() && !TypeUtils.acceptsNullable(asFlexibleType().upperBound) -> enhancementFromKotlin()
this is TypeWithEnhancement && enhancement.mustNotBeNull() != null -> enhancementFromJava()
else -> null
}
