org.jetbrains.kotlin.fir.resolve.inference.ConstraintSystemCompleter.kt Maven / Gradle / Ivy
/*
* Copyright 2010-2020 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.fir.resolve.inference
import org.jetbrains.kotlin.config.LanguageFeature
import org.jetbrains.kotlin.fir.FirElement
import org.jetbrains.kotlin.fir.diagnostics.ConeCannotInferTypeParameterType
import org.jetbrains.kotlin.fir.diagnostics.ConeSimpleDiagnostic
import org.jetbrains.kotlin.fir.diagnostics.DiagnosticKind
import org.jetbrains.kotlin.fir.expressions.*
import org.jetbrains.kotlin.fir.languageVersionSettings
import org.jetbrains.kotlin.fir.resolve.BodyResolveComponents
import org.jetbrains.kotlin.fir.resolve.calls.Candidate
import org.jetbrains.kotlin.fir.resolve.calls.FirNamedReferenceWithCandidate
import org.jetbrains.kotlin.fir.resolve.calls.ResolutionContext
import org.jetbrains.kotlin.fir.resolve.inference.model.ConeFixVariableConstraintPosition
import org.jetbrains.kotlin.fir.resolve.transformers.body.resolve.BodyResolveContext
import org.jetbrains.kotlin.fir.returnExpressions
import org.jetbrains.kotlin.fir.symbols.impl.FirTypeParameterSymbol
import org.jetbrains.kotlin.fir.types.ConeErrorType
import org.jetbrains.kotlin.fir.types.ConeKotlinType
import org.jetbrains.kotlin.fir.types.ConeTypeVariable
import org.jetbrains.kotlin.resolve.calls.inference.components.ConstraintSystemCompletionContext
import org.jetbrains.kotlin.resolve.calls.inference.components.ConstraintSystemCompletionMode
import org.jetbrains.kotlin.resolve.calls.inference.components.TypeVariableDependencyInformationProvider
import org.jetbrains.kotlin.resolve.calls.inference.components.TypeVariableDirectionCalculator
import org.jetbrains.kotlin.resolve.calls.inference.model.NewConstraintSystemImpl
import org.jetbrains.kotlin.resolve.calls.inference.model.NotEnoughInformationForTypeParameter
import org.jetbrains.kotlin.resolve.calls.inference.model.VariableWithConstraints
import org.jetbrains.kotlin.resolve.calls.model.PostponedAtomWithRevisableExpectedType
import org.jetbrains.kotlin.types.model.TypeConstructorMarker
import org.jetbrains.kotlin.types.model.TypeVariableMarker
import org.jetbrains.kotlin.utils.addIfNotNull
import org.jetbrains.kotlin.utils.addToStdlib.filterIsInstanceWithChecker
class ConstraintSystemCompleter(components: BodyResolveComponents, private val context: BodyResolveContext) {
private val inferenceComponents = components.session.inferenceComponents
val variableFixationFinder = inferenceComponents.variableFixationFinder
private val postponedArgumentsInputTypesResolver = inferenceComponents.postponedArgumentInputTypesResolver
private val languageVersionSettings = components.session.languageVersionSettings
fun complete(
c: ConstraintSystemCompletionContext,
completionMode: ConstraintSystemCompletionMode,
topLevelAtoms: List,
candidateReturnType: ConeKotlinType,
context: ResolutionContext,
collectVariablesFromContext: Boolean = false,
analyze: (PostponedResolvedAtom) -> Unit
) = c.runCompletion(completionMode, topLevelAtoms, candidateReturnType, context, collectVariablesFromContext, analyze)
private fun ConstraintSystemCompletionContext.runCompletion(
completionMode: ConstraintSystemCompletionMode,
topLevelAtoms: List,
topLevelType: ConeKotlinType,
context: ResolutionContext,
collectVariablesFromContext: Boolean = false,
analyze: (PostponedResolvedAtom) -> Unit
) {
val topLevelTypeVariables = topLevelType.extractTypeVariables()
if (completionMode == ConstraintSystemCompletionMode.FULL || completionMode == ConstraintSystemCompletionMode.UNTIL_FIRST_LAMBDA) {
resolveForkPointsConstraints()
}
completion@ while (true) {
// TODO: This is very slow, KT-59680
val postponedArguments = getOrderedNotAnalyzedPostponedArguments(topLevelAtoms)
if (completionMode == ConstraintSystemCompletionMode.UNTIL_FIRST_LAMBDA && hasLambdaToAnalyze(
languageVersionSettings,
postponedArguments
)
) return
// Stage 1: analyze postponed arguments with fixed parameter types
if (analyzeArgumentWithFixedParameterTypes(languageVersionSettings, postponedArguments, analyze))
continue
val isThereAnyReadyForFixationVariable = variableFixationFinder.findFirstVariableForFixation(
this,
getOrderedAllTypeVariables(collectVariablesFromContext, topLevelAtoms),
postponedArguments,
completionMode,
topLevelType
) != null
// If there aren't any postponed arguments and ready for fixation variables, then completion isn't needed: nothing to do
if (postponedArguments.isEmpty() && !isThereAnyReadyForFixationVariable)
break
val postponedArgumentsWithRevisableType = postponedArguments
.filterIsInstanceWithChecker {
// NB: FE 1.0 does not perform this check
it.revisedExpectedType == null
}
val dependencyProvider =
TypeVariableDependencyInformationProvider(notFixedTypeVariables, postponedArguments, topLevelType, this)
// Stage 2: collect parameter types for postponed arguments
val wasBuiltNewExpectedTypeForSomeArgument = postponedArgumentsInputTypesResolver.collectParameterTypesAndBuildNewExpectedTypes(
this,
postponedArgumentsWithRevisableType,
completionMode,
dependencyProvider,
topLevelTypeVariables
)
if (wasBuiltNewExpectedTypeForSomeArgument)
continue
if (completionMode == ConstraintSystemCompletionMode.FULL) {
// Stage 3: fix variables for parameter types of all postponed arguments
for (argument in postponedArguments) {
val variableWasFixed = postponedArgumentsInputTypesResolver.fixNextReadyVariableForParameterTypeIfNeeded(
this,
argument,
postponedArguments,
topLevelType,
dependencyProvider,
) {
// NB: FE 1.0 calls findResolvedAtomBy here
// atom provided here is used only inside constraint positions, omitting right now
null
}
if (variableWasFixed)
continue@completion
}
// Stage 4: create atoms with revised expected types if needed
for (argument in postponedArgumentsWithRevisableType) {
val argumentWasTransformed = transformToAtomWithNewFunctionExpectedType(
this, context, argument
)
if (argumentWasTransformed)
continue@completion
}
}
// Stage 5: analyze the next ready postponed argument
if (analyzeNextReadyPostponedArgument(languageVersionSettings, postponedArguments, completionMode, analyze))
continue
// Stage 6: fix next ready type variable with proper constraints
if (fixNextReadyVariable(completionMode, topLevelAtoms, topLevelType, collectVariablesFromContext, postponedArguments))
continue
// Stage 7: try to complete call with the builder inference if there are uninferred type variables
val allTypeVariables = getOrderedAllTypeVariables(collectVariablesFromContext, topLevelAtoms)
val areThereAppearedProperConstraintsForSomeVariable = tryToCompleteWithBuilderInference(
completionMode, topLevelType, postponedArguments, allTypeVariables, analyze
)
if (areThereAppearedProperConstraintsForSomeVariable)
continue
// Stage 8: report "not enough information" for uninferred type variables
reportNotEnoughTypeInformation(
completionMode, topLevelAtoms, topLevelType, allTypeVariables, postponedArguments
)
// Stage 9: force analysis of remaining not analyzed postponed arguments and rerun stages if there are
if (completionMode == ConstraintSystemCompletionMode.FULL) {
if (analyzeRemainingNotAnalyzedPostponedArgument(postponedArguments, analyze))
continue
}
break
}
}
/**
* General documentation for builder inference algorithm is located at `/docs/fir/builder_inference.md`
*
* This function checks if any of the postponed arguments are suitable for builder inference, and performs it for all eligible lambda arguments
* @return true if we got new proper constraints after builder inference
*/
private fun ConstraintSystemCompletionContext.tryToCompleteWithBuilderInference(
completionMode: ConstraintSystemCompletionMode,
topLevelType: ConeKotlinType,
postponedArguments: List,
allTypeVariables: List,
analyze: (PostponedResolvedAtom) -> Unit
): Boolean {
if (completionMode != ConstraintSystemCompletionMode.FULL) return false
// If we use the builder inference anyway (if the annotation is presented), then we are already analysed builder inference lambdas
if (!languageVersionSettings.supportsFeature(LanguageFeature.UseBuilderInferenceOnlyIfNeeded)) return false
val lambdaArguments = postponedArguments.filterIsInstance().takeIf { it.isNotEmpty() } ?: return false
// We assume useBuilderInferenceWithoutAnnotation = true for FIR
val builder = getBuilder()
for (argument in lambdaArguments) {
val notFixedInputTypeVariables = argument.inputTypes
.flatMap { it.extractTypeVariables() }.filter { it !in fixedTypeVariables }
if (notFixedInputTypeVariables.isEmpty()) continue
for (variable in notFixedInputTypeVariables) {
builder.markPostponedVariable(notFixedTypeVariables.getValue(variable).typeVariable)
}
analyze(argument)
}
val variableForFixation = variableFixationFinder.findFirstVariableForFixation(
this, allTypeVariables, postponedArguments, completionMode, topLevelType
)
// continue completion (rerun stages) only if ready for fixation variables with proper constraints have appeared
// (after analysing a lambda with the builder inference)
// otherwise we don't continue and report "not enough type information" error
return variableForFixation?.hasProperConstraint == true
}
private fun transformToAtomWithNewFunctionExpectedType(
c: ConstraintSystemCompletionContext,
resolutionContext: ResolutionContext,
argument: PostponedAtomWithRevisableExpectedType,
): Boolean = with(c) {
val revisedExpectedType = argument.revisedExpectedType
?.takeIf { it.isFunctionOrKFunctionWithAnySuspendability() } as ConeKotlinType?
?: return false
when (argument) {
is ResolvedCallableReferenceAtom ->
argument.reviseExpectedType(revisedExpectedType)
is LambdaWithTypeVariableAsExpectedTypeAtom ->
argument.transformToResolvedLambda(c.getBuilder(), resolutionContext, revisedExpectedType)
else -> throw IllegalStateException("Unsupported postponed argument type of $argument")
}
return true
}
private fun ConstraintSystemCompletionContext.fixNextReadyVariable(
completionMode: ConstraintSystemCompletionMode,
topLevelAtoms: List,
topLevelType: ConeKotlinType,
collectVariablesFromContext: Boolean,
postponedArguments: List,
): Boolean {
val variableForFixation = variableFixationFinder.findFirstVariableForFixation(
this,
getOrderedAllTypeVariables(collectVariablesFromContext, topLevelAtoms),
postponedArguments,
completionMode,
topLevelType
) ?: return false
val variableWithConstraints = notFixedTypeVariables.getValue(variableForFixation.variable)
if (!variableForFixation.hasProperConstraint) {
if (context.inferenceSession.isSyntheticTypeVariable(variableWithConstraints.typeVariable)) {
context.inferenceSession.fixSyntheticTypeVariableWithNotEnoughInformation(
variableWithConstraints.typeVariable as ConeTypeVariable,
this
)
return true
}
return false
}
fixVariable(this, variableWithConstraints)
return true
}
private fun ConstraintSystemCompletionContext.reportNotEnoughTypeInformation(
completionMode: ConstraintSystemCompletionMode,
topLevelAtoms: List,
topLevelType: ConeKotlinType,
allTypeVariables: List,
postponedArguments: List,
) {
while (true) {
val variableForFixation = variableFixationFinder.findFirstVariableForFixation(
this, allTypeVariables, postponedArguments, completionMode, topLevelType,
) ?: break
assert(!variableForFixation.hasProperConstraint) {
"At this stage there should be no remaining variables with proper constraints"
}
if (completionMode == ConstraintSystemCompletionMode.PARTIAL) break
val variableWithConstraints = notFixedTypeVariables.getValue(variableForFixation.variable)
processVariableWhenNotEnoughInformation(variableWithConstraints, topLevelAtoms)
}
}
private fun ConstraintSystemCompletionContext.processVariableWhenNotEnoughInformation(
variableWithConstraints: VariableWithConstraints,
topLevelAtoms: List,
) {
val typeVariable = variableWithConstraints.typeVariable
val resolvedAtom = findResolvedAtomBy(typeVariable, topLevelAtoms) ?: topLevelAtoms.firstOrNull()
if (resolvedAtom != null) {
addError(
NotEnoughInformationForTypeParameter(typeVariable, resolvedAtom, couldBeResolvedWithUnrestrictedBuilderInference())
)
}
val resultErrorType = when (typeVariable) {
is ConeTypeParameterBasedTypeVariable ->
createCannotInferErrorType(
typeVariable.typeParameterSymbol,
"Cannot infer argument for type parameter ${typeVariable.typeParameterSymbol.name}",
isUninferredParameter = true,
)
is ConeTypeVariableForLambdaParameterType -> createCannotInferErrorType(
typeParameterSymbol = null,
message = "Cannot infer lambda parameter type"
)
else -> createCannotInferErrorType(typeParameterSymbol = null, "Cannot infer type variable $typeVariable")
}
fixVariable(typeVariable, resultErrorType, ConeFixVariableConstraintPosition(typeVariable))
}
private fun ConstraintSystemCompletionContext.getOrderedAllTypeVariables(
collectVariablesFromContext: Boolean,
topLevelAtoms: List
): List {
if (collectVariablesFromContext) {
return notFixedTypeVariables.keys.toList()
}
val result = LinkedHashSet(notFixedTypeVariables.size)
fun ConeTypeVariable?.toTypeConstructor(): TypeConstructorMarker? =
this?.typeConstructor?.takeIf { it in notFixedTypeVariables.keys }
fun PostponedAtomWithRevisableExpectedType.collectNotFixedVariables() {
revisedExpectedType?.lowerBoundIfFlexible()?.asArgumentList()?.let { typeArgumentList ->
for (typeArgument in typeArgumentList) {
val constructor = typeArgument.getType().typeConstructor()
if (constructor in notFixedTypeVariables) {
result.add(constructor)
}
}
}
}
fun FirStatement.collectAllTypeVariables() {
this.processAllContainingCallCandidates(processBlocks = true) { candidate ->
candidate.freshVariables.mapNotNullTo(result) { typeVariable ->
typeVariable.toTypeConstructor()
}
for (postponedAtom in candidate.postponedAtoms) {
when (postponedAtom) {
is ResolvedLambdaAtom -> {
result.addIfNotNull(postponedAtom.typeVariableForLambdaReturnType.toTypeConstructor())
}
is LambdaWithTypeVariableAsExpectedTypeAtom -> {
postponedAtom.collectNotFixedVariables()
}
is ResolvedCallableReferenceAtom -> {
if (postponedAtom.mightNeedAdditionalResolution) {
postponedAtom.collectNotFixedVariables()
}
}
// ResolvedCallAtom?
// ResolvedCallableReferenceArgumentAtom?
}
}
}
}
for (topLevelAtom in topLevelAtoms) {
topLevelAtom.collectAllTypeVariables()
}
if (context.inferenceSession.hasSyntheticTypeVariables()) {
result.addAll(notFixedTypeVariables.filter { context.inferenceSession.isSyntheticTypeVariable(it.value.typeVariable) }.keys.asIterable())
}
require(result.size == notFixedTypeVariables.size) {
val notFoundTypeVariables = notFixedTypeVariables.keys.toMutableSet().apply { removeAll(result) }
"Not all type variables found: $notFoundTypeVariables"
}
return result.toList()
}
private fun fixVariable(
c: ConstraintSystemCompletionContext,
variableWithConstraints: VariableWithConstraints
) {
val resultType = inferenceComponents.resultTypeResolver.findResultType(
c,
variableWithConstraints,
TypeVariableDirectionCalculator.ResolveDirection.UNKNOWN
)
val variable = variableWithConstraints.typeVariable
c.fixVariable(variable, resultType, ConeFixVariableConstraintPosition(variable))
}
companion object {
internal fun getOrderedNotAnalyzedPostponedArguments(candidate: Candidate): List {
val callSite = candidate.callInfo.callSite as? FirStatement ?: return emptyList()
return getOrderedNotAnalyzedPostponedArguments(listOf(callSite))
}
private fun getOrderedNotAnalyzedPostponedArguments(topLevelAtoms: List): List {
val notAnalyzedArguments = arrayListOf()
for (primitive in topLevelAtoms) {
primitive.processAllContainingCallCandidates(
// TODO: remove this argument and relevant parameter, KT-59679
// Currently, it's used because otherwise problem happens with a lambda in a try-block (see tryWithLambdaInside test)
processBlocks = true
) { candidate ->
candidate.postponedAtoms.forEach { atom ->
notAnalyzedArguments.addIfNotNull((atom as? PostponedResolvedAtom)?.takeUnless { it.analyzed })
}
}
}
return notAnalyzedArguments
}
private fun findResolvedAtomBy(
typeVariable: TypeVariableMarker,
topLevelAtoms: List
): FirStatement? {
fun FirStatement.findFirstAtomContainingVariable(): FirStatement? {
var result: FirStatement? = null
fun suggestElement(element: FirElement) {
if (result == null && element is FirStatement) {
result = element
}
}
this@findFirstAtomContainingVariable.processAllContainingCallCandidates(processBlocks = true) { candidate ->
if (typeVariable in candidate.freshVariables) {
suggestElement(candidate.callInfo.callSite)
}
for (postponedAtom in candidate.postponedAtoms) {
if (postponedAtom is ResolvedLambdaAtom) {
if (postponedAtom.typeVariableForLambdaReturnType == typeVariable) {
suggestElement(postponedAtom.atom)
}
}
}
}
return result
}
return topLevelAtoms.firstNotNullOfOrNull(FirStatement::findFirstAtomContainingVariable)
}
private fun createCannotInferErrorType(
typeParameterSymbol: FirTypeParameterSymbol?,
message: String,
isUninferredParameter: Boolean = false
): ConeErrorType {
val diagnostic = when (typeParameterSymbol) {
null -> ConeSimpleDiagnostic(message, DiagnosticKind.CannotInferParameterType)
else -> ConeCannotInferTypeParameterType(
typeParameterSymbol,
message,
)
}
return ConeErrorType(diagnostic, isUninferredParameter,)
}
}
}
fun FirStatement.processAllContainingCallCandidates(processBlocks: Boolean, processor: (Candidate) -> Unit) {
when (this) {
is FirFunctionCall -> {
processCandidateIfApplicable(processor, processBlocks)
this.arguments.forEach { it.processAllContainingCallCandidates(processBlocks, processor) }
}
is FirSafeCallExpression -> {
this.selector.processAllContainingCallCandidates(processBlocks, processor)
}
is FirWhenExpression -> {
processCandidateIfApplicable(processor, processBlocks)
this.branches.forEach { it.result.processAllContainingCallCandidates(processBlocks, processor) }
}
is FirTryExpression -> {
processCandidateIfApplicable(processor, processBlocks)
tryBlock.processAllContainingCallCandidates(processBlocks, processor)
catches.forEach { it.block.processAllContainingCallCandidates(processBlocks, processor) }
}
is FirCheckNotNullCall -> {
processCandidateIfApplicable(processor, processBlocks)
this.arguments.forEach { it.processAllContainingCallCandidates(processBlocks, processor) }
}
is FirQualifiedAccessExpression -> {
processCandidateIfApplicable(processor, processBlocks)
}
is FirVariableAssignment -> {
(lValue as? FirResolvable)?.processCandidateIfApplicable(processor, processBlocks)
rValue.processAllContainingCallCandidates(processBlocks, processor)
}
is FirWrappedArgumentExpression -> this.expression.processAllContainingCallCandidates(processBlocks, processor)
is FirBlock -> {
if (processBlocks) {
this.returnExpressions().forEach { it.processAllContainingCallCandidates(processBlocks, processor) }
}
}
is FirDelegatedConstructorCall -> {
processCandidateIfApplicable(processor, processBlocks)
this.arguments.forEach { it.processAllContainingCallCandidates(processBlocks, processor) }
}
is FirElvisExpression -> {
processCandidateIfApplicable(processor, processBlocks)
lhs.processAllContainingCallCandidates(processBlocks, processor)
rhs.processAllContainingCallCandidates(processBlocks, processor)
}
is FirAnnotationCall -> {
processCandidateIfApplicable(processor, processBlocks)
arguments.forEach { it.processAllContainingCallCandidates(processBlocks, processor) }
}
}
}
private fun FirResolvable.processCandidateIfApplicable(
processor: (Candidate) -> Unit,
processBlocks: Boolean
) {
val candidate = (calleeReference as? FirNamedReferenceWithCandidate)?.candidate ?: return
processor(candidate)
for (atom in candidate.postponedAtoms) {
if (atom !is ResolvedLambdaAtom || !atom.analyzed) continue
atom.returnStatements.forEach {
it.processAllContainingCallCandidates(processBlocks, processor)
}
}
}
val Candidate.csBuilder: NewConstraintSystemImpl get() = system.getBuilder()
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