[NI] Add feature for choosing candidate by lambda return type

compiler/fir/analysis-tests/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestWithStdlibGenerated.java

@@ -1788,6 +1788,29 @@ public class FirOldFrontendDiagnosticsTestWithStdlibGenerated extends AbstractFi
         }
     }
 
+    @TestMetadata("compiler/testData/diagnostics/testsWithStdLib/factoryPattern")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class FactoryPattern extends AbstractFirOldFrontendDiagnosticsTestWithStdlib {
+        private void runTest(String testDataFilePath) throws Exception {
+            KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
+        }
+
+        public void testAllFilesPresentInFactoryPattern() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/testsWithStdLib/factoryPattern"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+        }
+
+        @TestMetadata("overloadByLambdaReturnType_disabled.kt")
+        public void testOverloadByLambdaReturnType_disabled() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_disabled.kt");
+        }
+
+        @TestMetadata("overloadByLambdaReturnType_enabled.kt")
+        public void testOverloadByLambdaReturnType_enabled() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_enabled.kt");
+        }
+    }
+
     @TestMetadata("compiler/testData/diagnostics/testsWithStdLib/forInArrayLoop")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirCallCompleter.kt

@@ -119,6 +119,8 @@ class FirCallCompleter(
                 inferenceSession.addPartiallyResolvedCall(approximatedCall)
                 CompletionResult(approximatedCall, false)
             }
+
+            ConstraintSystemCompletionMode.UNTIL_FIRST_LAMBDA -> throw IllegalStateException()
         }
     }
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/tower/KotlinResolutionCallbacksImpl.kt

@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.builtins.KotlinBuiltIns.isPrimitiveTypeOrNullablePri
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns.isUnderKotlinPackage
 import org.jetbrains.kotlin.builtins.UnsignedTypes
 import org.jetbrains.kotlin.builtins.createFunctionType
+import org.jetbrains.kotlin.builtins.isFunctionTypeOrSubtype
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
@@ -196,8 +197,10 @@ class KotlinResolutionCallbacksImpl(
         val functionTypeInfo = expressionTypingServices.getTypeInfo(psiCallArgument.expression, actualContext)
         (temporaryTrace ?: trace).record(BindingContext.NEW_INFERENCE_LAMBDA_INFO, psiCallArgument.ktFunction, LambdaInfo.STUB_EMPTY)
 
+        val inferedReturnType = functionTypeInfo.type?.arguments?.last()?.type?.takeIf { functionTypeInfo.type?.isFunctionTypeOrSubtype == true }
+
         if (coroutineSession?.hasInapplicableCall() == true) {
-            return ReturnArgumentsAnalysisResult(ReturnArgumentsInfo.empty, coroutineSession, hasInapplicableCallForBuilderInference = true)
+            return ReturnArgumentsAnalysisResult(ReturnArgumentsInfo.empty, coroutineSession, inferedReturnType, hasInapplicableCallForBuilderInference = true)
         } else {
             temporaryTrace?.commit()
         }
@@ -244,7 +247,8 @@ class KotlinResolutionCallbacksImpl(
                 lastExpressionCoercedToUnit,
                 returnArgumentFound
             ),
-            coroutineSession
+            coroutineSession,
+            inferedReturnType
         )
     }
 

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/KotlinCallResolver.kt

@@ -18,15 +18,14 @@ package org.jetbrains.kotlin.resolve.calls
 
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.progress.ProgressIndicatorAndCompilationCanceledStatus
-import org.jetbrains.kotlin.resolve.calls.components.CallableReferenceResolver
+import org.jetbrains.kotlin.resolve.calls.components.*
-import org.jetbrains.kotlin.resolve.calls.components.KotlinCallCompleter
-import org.jetbrains.kotlin.resolve.calls.components.KotlinResolutionCallbacks
-import org.jetbrains.kotlin.resolve.calls.components.NewOverloadingConflictResolver
 import org.jetbrains.kotlin.resolve.calls.context.CheckArgumentTypesMode
 import org.jetbrains.kotlin.resolve.calls.model.*
 import org.jetbrains.kotlin.resolve.calls.tower.*
 import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValueWithSmartCastInfo
 import org.jetbrains.kotlin.types.UnwrappedType
+import org.jetbrains.kotlin.types.model.safeSubstitute
+import org.jetbrains.kotlin.utils.addToStdlib.same
 import java.lang.UnsupportedOperationException
 
 
@@ -142,13 +141,19 @@ class KotlinCallResolver(
             }
         }
 
-        val maximallySpecificCandidates = overloadingConflictResolver.chooseMaximallySpecificCandidates(
+        var maximallySpecificCandidates = overloadingConflictResolver.chooseMaximallySpecificCandidates(
             refinedCandidates,
             CheckArgumentTypesMode.CHECK_VALUE_ARGUMENTS,
             discriminateGenerics = true // todo
         )
 
+        if (maximallySpecificCandidates.size > 1 && callComponents.languageVersionSettings.supportsFeature(LanguageFeature.FactoryPatternResolution)) {
+            maximallySpecificCandidates = kotlinCallCompleter.chooseCandidateRegardingFactoryPatternResolution(maximallySpecificCandidates, resolutionCallbacks)
+        }
+
         return kotlinCallCompleter.runCompletion(candidateFactory, maximallySpecificCandidates, expectedType, resolutionCallbacks)
     }
+
+
 }
 

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/ExternalComponents.kt

@@ -59,6 +59,7 @@ data class ReturnArgumentsInfo(
 data class ReturnArgumentsAnalysisResult(
     val returnArgumentsInfo: ReturnArgumentsInfo,
     val inferenceSession: InferenceSession?,
+    val lambdaReturnType: KotlinType? = null,
     val hasInapplicableCallForBuilderInference: Boolean = false
 )
 

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/KotlinCallCompleter.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.resolve.calls.components
 
+import org.jetbrains.kotlin.builtins.isFunctionTypeOrSubtype
 import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.synthetic.SyntheticMemberDescriptor
@@ -15,11 +16,15 @@ import org.jetbrains.kotlin.resolve.calls.inference.components.KotlinConstraintS
 import org.jetbrains.kotlin.resolve.calls.inference.components.TrivialConstraintTypeInferenceOracle
 import org.jetbrains.kotlin.resolve.calls.inference.model.ConstraintStorage.Empty.hasContradiction
 import org.jetbrains.kotlin.resolve.calls.inference.model.ExpectedTypeConstraintPosition
+import org.jetbrains.kotlin.resolve.calls.inference.model.LambdaArgumentConstraintPosition
+import org.jetbrains.kotlin.resolve.calls.inference.model.TypeVariableTypeConstructor
 import org.jetbrains.kotlin.resolve.calls.model.*
 import org.jetbrains.kotlin.resolve.calls.tower.forceResolution
 import org.jetbrains.kotlin.types.ErrorUtils
 import org.jetbrains.kotlin.types.TypeUtils
 import org.jetbrains.kotlin.types.UnwrappedType
+import org.jetbrains.kotlin.types.model.safeSubstitute
+import org.jetbrains.kotlin.utils.addToStdlib.same
 
 class KotlinCallCompleter(
     private val postponedArgumentsAnalyzer: PostponedArgumentsAnalyzer,
@@ -66,10 +71,89 @@ class KotlinCallCompleter(
                 candidate.runCompletion(completionMode, diagnosticHolder, resolutionCallbacks)
                 candidate.asCallResolutionResult(completionMode, diagnosticHolder)
             }
+            ConstraintSystemCompletionMode.UNTIL_FIRST_LAMBDA -> throw IllegalStateException("Should not be here")
 
         }
     }
 
+    fun chooseCandidateRegardingFactoryPatternResolution(
+        candidates: Set<KotlinResolutionCandidate>,
+        resolutionCallbacks: KotlinResolutionCallbacks
+    ): Set<KotlinResolutionCandidate> {
+        val lambdas = candidates.flatMap { candidate ->
+            candidate.getSubResolvedAtoms()
+                .filter { it is ResolvedLambdaAtom && !it.analyzed }
+                .map { candidate to it as ResolvedLambdaAtom }
+        }.groupBy { (_, atom) -> atom.atom }
+            .values
+            .singleOrNull()
+            ?.toMap() ?: return candidates
+
+        if (!lambdas.values.same { it.parameters.size }) return candidates
+        if (!lambdas.values.all { it.expectedType?.isFunctionTypeOrSubtype == true }) return candidates
+
+        for (candidate in lambdas.keys) {
+            candidate.runCompletion(
+                ConstraintSystemCompletionMode.UNTIL_FIRST_LAMBDA,
+                candidate,
+                resolutionCallbacks
+            )
+        }
+        if (!lambdas.entries.same { (candidate, atom) -> candidate.getInputTypesOfLambdaAtom(atom) }) {
+            return candidates
+        }
+
+        val newAtoms = mutableMapOf<KotlinResolutionCandidate, ResolvedLambdaAtom>()
+        for ((candidate, atom) in lambdas.entries) {
+            newAtoms[candidate] = kotlinConstraintSystemCompleter.prepareLambdaAtomForFactoryPattern(atom, candidate, candidate)
+        }
+
+        val diagnosticHolderForLambda = KotlinDiagnosticsHolder.SimpleHolder()
+        val iterator = newAtoms.entries.iterator()
+        val (firstCandidate, firstAtom) = iterator.next()
+        val results = postponedArgumentsAnalyzer.analyzeLambda(
+            firstCandidate.getSystem().asPostponedArgumentsAnalyzerContext(),
+            resolutionCallbacks,
+            firstAtom,
+            diagnosticHolderForLambda
+        )
+        lambdas.getValue(firstCandidate).setAnalyzedResults(results.returnArgumentsInfo, listOf(firstAtom))
+
+        val lambdaReturnType = results.lambdaReturnType ?: return candidates
+        while (iterator.hasNext()) {
+            val (candidate, atom) = iterator.next()
+            atom.setAnalyzedResults(results.returnArgumentsInfo, firstAtom.subResolvedAtoms!!)
+            lambdas.getValue(candidate).setAnalyzedResults(results.returnArgumentsInfo, listOf(atom))
+            candidate.csBuilder.addSubtypeConstraint(lambdaReturnType, atom.returnType, LambdaArgumentConstraintPosition(atom))
+        }
+
+        val errorCandidates = mutableSetOf<KotlinResolutionCandidate>()
+        val successfulCandidates = mutableSetOf<KotlinResolutionCandidate>()
+
+        for (candidate in candidates) {
+            if (candidate.isSuccessful) {
+                successfulCandidates += candidate
+            } else {
+                errorCandidates += candidate
+            }
+        }
+        return when {
+            successfulCandidates.isNotEmpty() -> successfulCandidates
+            else -> errorCandidates
+        }
+    }
+
+    private fun KotlinResolutionCandidate.getInputTypesOfLambdaAtom(atom: ResolvedLambdaAtom): List<UnwrappedType> {
+        val result = mutableListOf<UnwrappedType>()
+        val substitutor = csBuilder.buildCurrentSubstitutor()
+        val ctx = getSystem().asConstraintSystemCompleterContext()
+        for (inputType in atom.inputTypes) {
+            result += substitutor.safeSubstitute(ctx, inputType) as UnwrappedType
+        }
+        return result
+    }
+
+
     private fun KotlinResolutionCandidate.checkSamWithVararg(diagnosticHolder: KotlinDiagnosticsHolder.SimpleHolder) {
         val samConversionPerArgumentWithWarningsForVarargAfterSam =
             callComponents.languageVersionSettings.supportsFeature(LanguageFeature.SamConversionPerArgument) &&

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/PostponeArgumentsChecks.kt

@@ -220,6 +220,24 @@ fun LambdaWithTypeVariableAsExpectedTypeAtom.transformToResolvedLambda(
     return resolvedLambdaAtom
 }
 
+fun ResolvedLambdaAtom.transformToResolvedLambda(
+    csBuilder: ConstraintSystemBuilder,
+    diagnosticsHolder: KotlinDiagnosticsHolder,
+    expectedType: UnwrappedType,
+    returnTypeVariable: TypeVariableForLambdaReturnType? = null
+): ResolvedLambdaAtom {
+    val resolvedLambdaAtom = preprocessLambdaArgument(
+        csBuilder,
+        atom,
+        expectedType,
+        diagnosticsHolder,
+        forceResolution = true,
+        returnTypeVariable = returnTypeVariable
+    ) as ResolvedLambdaAtom
+
+    return resolvedLambdaAtom
+}
+
 private fun preprocessCallableReference(
     csBuilder: ConstraintSystemBuilder,
     argument: CallableReferenceKotlinCallArgument,

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/components/PostponedArgumentsAnalyzer.kt

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.resolve.calls.inference.model.ConstraintStorage
 import org.jetbrains.kotlin.resolve.calls.inference.model.CoroutinePosition
 import org.jetbrains.kotlin.resolve.calls.inference.model.LambdaArgumentConstraintPosition
 import org.jetbrains.kotlin.resolve.calls.model.*
+import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.UnwrappedType
 import org.jetbrains.kotlin.types.model.*
 import org.jetbrains.kotlin.types.typeUtil.builtIns
@@ -65,12 +66,12 @@ class PostponedArgumentsAnalyzer(
         }
     }
 
-    private fun analyzeLambda(
+    fun analyzeLambda(
         c: Context,
         resolutionCallbacks: KotlinResolutionCallbacks,
         lambda: ResolvedLambdaAtom,
         diagnosticHolder: KotlinDiagnosticsHolder
-    ) {
+    ): ReturnArgumentsAnalysisResult {
         val stubsForPostponedVariables = c.bindingStubsForPostponedVariables()
         val currentSubstitutor = c.buildCurrentSubstitutor(stubsForPostponedVariables.mapKeys { it.key.freshTypeConstructor(c) })
 
@@ -120,20 +121,21 @@ class PostponedArgumentsAnalyzer(
             else FilteredAnnotations(annotations, true) { it != KotlinBuiltIns.FQ_NAMES.extensionFunctionType }
         }
 
-        val (returnArgumentsInfo, inferenceSession, hasInapplicableCallForBuilderInference) =
+        val returnArgumentsAnalysisResult = resolutionCallbacks.analyzeAndGetLambdaReturnArguments(
-            resolutionCallbacks.analyzeAndGetLambdaReturnArguments(
+            lambda.atom,
-                lambda.atom,
+            lambda.isSuspend,
-                lambda.isSuspend,
+            receiver,
-                receiver,
+            parameters,
-                parameters,
+            expectedTypeForReturnArguments,
-                expectedTypeForReturnArguments,
+            convertedAnnotations ?: Annotations.EMPTY,
-                convertedAnnotations ?: Annotations.EMPTY,
+            stubsForPostponedVariables.cast()
-                stubsForPostponedVariables.cast()
+        )
-            )
+        val (returnArgumentsInfo, inferenceSession, inferedReturnType, hasInapplicableCallForBuilderInference) =
+            returnArgumentsAnalysisResult
 
         if (hasInapplicableCallForBuilderInference) {
             c.getBuilder().removePostponedVariables()
-            return
+            return returnArgumentsAnalysisResult
         }
 
         val returnArguments = returnArgumentsInfo.nonErrorArguments
@@ -169,7 +171,7 @@ class PostponedArgumentsAnalyzer(
             val postponedVariables = inferenceSession.inferPostponedVariables(lambda, storageSnapshot, diagnosticHolder)
             if (postponedVariables == null) {
                 c.getBuilder().removePostponedVariables()
-                return
+                return returnArgumentsAnalysisResult
             }
 
             for ((constructor, resultType) in postponedVariables) {
@@ -180,6 +182,8 @@ class PostponedArgumentsAnalyzer(
                 c.getBuilder().addEqualityConstraint(variable.defaultType(c), resultType, CoroutinePosition())
             }
         }
+
+        return returnArgumentsAnalysisResult
     }
 
     private fun UnwrappedType?.receiver(): UnwrappedType? {

compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/inference/components/KotlinConstraintSystemCompleter.kt

@@ -5,6 +5,7 @@
 
 package org.jetbrains.kotlin.resolve.calls.inference.components
 
+import org.jetbrains.kotlin.resolve.calls.components.transformToResolvedLambda
 import org.jetbrains.kotlin.resolve.calls.inference.ConstraintSystemBuilder
 import org.jetbrains.kotlin.resolve.calls.inference.model.*
 import org.jetbrains.kotlin.resolve.calls.model.*
@@ -12,6 +13,8 @@ import org.jetbrains.kotlin.types.*
 import org.jetbrains.kotlin.types.model.KotlinTypeMarker
 import org.jetbrains.kotlin.types.model.TypeConstructorMarker
 import org.jetbrains.kotlin.types.model.TypeVariableMarker
+import org.jetbrains.kotlin.types.model.safeSubstitute
+import org.jetbrains.kotlin.types.typeUtil.asTypeProjection
 import org.jetbrains.kotlin.utils.addIfNotNull
 import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 import kotlin.collections.LinkedHashSet
@@ -24,7 +27,8 @@ class KotlinConstraintSystemCompleter(
 
     enum class ConstraintSystemCompletionMode {
         FULL,
-        PARTIAL
+        PARTIAL,
+        UNTIL_FIRST_LAMBDA
     }
 
     interface Context : VariableFixationFinder.Context, ResultTypeResolver.Context {
@@ -91,7 +95,9 @@ class KotlinConstraintSystemCompleter(
         analyze: (PostponedResolvedAtom) -> Unit
     ) {
         completion@ while (true) {
+            // TODO
             val postponedArguments = getOrderedNotAnalyzedPostponedArguments(topLevelAtoms)
+            if (completionMode == ConstraintSystemCompletionMode.UNTIL_FIRST_LAMBDA && hasLambdaToAnalyze(postponedArguments)) return
 
             // Stage 1: analyze postponed arguments with fixed parameter types
             if (analyzeArgumentWithFixedParameterTypes(postponedArguments, analyze))
@@ -210,6 +216,35 @@ class KotlinConstraintSystemCompleter(
         return false
     }
 
+    fun prepareLambdaAtomForFactoryPattern(
+        atom: ResolvedLambdaAtom,
+        candidate: KotlinResolutionCandidate,
+        diagnosticsHolder: KotlinDiagnosticsHolder,
+    ): ResolvedLambdaAtom {
+        val returnVariable = TypeVariableForLambdaReturnType(candidate.callComponents.builtIns, "_R")
+        val csBuilder = candidate.csBuilder
+        csBuilder.registerVariable(returnVariable)
+        val functionalType: KotlinType = csBuilder.buildCurrentSubstitutor().safeSubstitute(candidate.getSystem().asConstraintSystemCompleterContext(), atom.expectedType!!) as KotlinType
+        val expectedType = KotlinTypeFactory.simpleType(
+            functionalType.annotations,
+            functionalType.constructor,
+            functionalType.arguments.dropLast(1) + returnVariable.defaultType.asTypeProjection(),
+            functionalType.isMarkedNullable
+        )
+        csBuilder.addSubtypeConstraint(
+            expectedType,
+            functionalType,
+            ArgumentConstraintPosition(atom.atom)
+        )
+        return atom.transformToResolvedLambda(csBuilder, diagnosticsHolder, expectedType, returnVariable)
+    }
+
+    private fun Context.hasLambdaToAnalyze(
+        postponedArguments: List<PostponedResolvedAtom>
+    ): Boolean {
+        return analyzeArgumentWithFixedParameterTypes(postponedArguments) {}
+    }
+
     private fun findPostponedArgumentWithRevisableExpectedType(postponedArguments: List<PostponedResolvedAtom>) =
         postponedArguments.firstOrNull { argument -> argument is PostponedAtomWithRevisableExpectedType }
 

compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_disabled.fir.kt

@@ -0,0 +1,36 @@
+// !LANGUAGE: +NewInference -FactoryPatternResolution
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION
+// ISSUE: KT-11265
+
+fun create(f: (Int) -> Int): Int = 1
+fun create(f: (Int) -> String): String = ""
+
+fun takeString(s: String) {}
+fun takeInt(s: Int) {}
+
+fun test_1() {
+    val x = <!AMBIGUITY!>create<!> { "" }
+    takeString(x)
+}
+
+fun test_2() {
+    val x = <!AMBIGUITY!>create<!> { 1 }
+    takeInt(x)
+}
+
+fun test_3() {
+    val x = <!AMBIGUITY!>create<!> { 1.0 }
+}
+
+fun <K> create(x: K, f: (K) -> Int): Int = 1
+fun <T> create(x: T, f: (T) -> String): String = ""
+
+fun test_4() {
+    val x = <!AMBIGUITY!>create<!>("") { "" }
+    takeString(x)
+}
+
+fun test_5() {
+    val x = <!AMBIGUITY!>create<!>("") { 1 }
+    takeInt(x)
+}

compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_disabled.kt

@@ -0,0 +1,36 @@
+// !LANGUAGE: +NewInference -FactoryPatternResolution
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION
+// ISSUE: KT-11265
+
+fun create(f: (Int) -> Int): Int = 1
+fun create(f: (Int) -> String): String = ""
+
+fun takeString(s: String) {}
+fun takeInt(s: Int) {}
+
+fun test_1() {
+    val x = <!OVERLOAD_RESOLUTION_AMBIGUITY!>create<!> { "" }
+    takeString(<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!>)
+}
+
+fun test_2() {
+    val x = <!OVERLOAD_RESOLUTION_AMBIGUITY!>create<!> { 1 }
+    takeInt(<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!>)
+}
+
+fun test_3() {
+    val x = <!OVERLOAD_RESOLUTION_AMBIGUITY!>create<!> { 1.0 }
+}
+
+fun <K> create(x: K, f: (K) -> Int): Int = 1
+fun <T> create(x: T, f: (T) -> String): String = ""
+
+fun test_4() {
+    val x = <!OVERLOAD_RESOLUTION_AMBIGUITY!>create<!>("") { "" }
+    takeString(<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!>)
+}
+
+fun test_5() {
+    val x = <!OVERLOAD_RESOLUTION_AMBIGUITY!>create<!>("") { 1 }
+    takeInt(<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!>)
+}

compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_disabled.txt

@@ -0,0 +1,13 @@
+package
+
+public fun create(/*0*/ f: (kotlin.Int) -> kotlin.Int): kotlin.Int
+public fun create(/*0*/ f: (kotlin.Int) -> kotlin.String): kotlin.String
+public fun </*0*/ K> create(/*0*/ x: K, /*1*/ f: (K) -> kotlin.Int): kotlin.Int
+public fun </*0*/ T> create(/*0*/ x: T, /*1*/ f: (T) -> kotlin.String): kotlin.String
+public fun takeInt(/*0*/ s: kotlin.Int): kotlin.Unit
+public fun takeString(/*0*/ s: kotlin.String): kotlin.Unit
+public fun test_1(): kotlin.Unit
+public fun test_2(): kotlin.Unit
+public fun test_3(): kotlin.Unit
+public fun test_4(): kotlin.Unit
+public fun test_5(): kotlin.Unit

compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_enabled.fir.kt

@@ -0,0 +1,36 @@
+// !LANGUAGE: +NewInference +FactoryPatternResolution
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION
+// ISSUE: KT-11265
+
+fun create(f: (Int) -> Int): Int = 1
+fun create(f: (Int) -> String): String = ""
+
+fun takeString(s: String) {}
+fun takeInt(s: Int) {}
+
+fun test_1() {
+    val x = <!AMBIGUITY!>create<!> { "" }
+    takeString(x)
+}
+
+fun test_2() {
+    val x = <!AMBIGUITY!>create<!> { 1 }
+    takeInt(x)
+}
+
+fun test_3() {
+    val x = <!AMBIGUITY!>create<!> { 1.0 }
+}
+
+fun <K> create(x: K, f: (K) -> Int): Int = 1
+fun <T> create(x: T, f: (T) -> String): String = ""
+
+fun test_4() {
+    val x = <!AMBIGUITY!>create<!>("") { "" }
+    takeString(x)
+}
+
+fun test_5() {
+    val x = <!AMBIGUITY!>create<!>("") { 1 }
+    takeInt(x)
+}

compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_enabled.kt

@@ -0,0 +1,36 @@
+// !LANGUAGE: +NewInference +FactoryPatternResolution
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION
+// ISSUE: KT-11265
+
+fun create(f: (Int) -> Int): Int = 1
+fun create(f: (Int) -> String): String = ""
+
+fun takeString(s: String) {}
+fun takeInt(s: Int) {}
+
+fun test_1() {
+    val x = create { "" }
+    takeString(x)
+}
+
+fun test_2() {
+    val x = create { 1 }
+    takeInt(x)
+}
+
+fun test_3() {
+    val x = <!NONE_APPLICABLE!>create<!> { 1.0 }
+}
+
+fun <K> create(x: K, f: (K) -> Int): Int = 1
+fun <T> create(x: T, f: (T) -> String): String = ""
+
+fun test_4() {
+    val x = create("") { "" }
+    takeString(x)
+}
+
+fun test_5() {
+    val x = create("") { 1 }
+    takeInt(x)
+}

compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_enabled.txt

@@ -0,0 +1,13 @@
+package
+
+public fun create(/*0*/ f: (kotlin.Int) -> kotlin.Int): kotlin.Int
+public fun create(/*0*/ f: (kotlin.Int) -> kotlin.String): kotlin.String
+public fun </*0*/ K> create(/*0*/ x: K, /*1*/ f: (K) -> kotlin.Int): kotlin.Int
+public fun </*0*/ T> create(/*0*/ x: T, /*1*/ f: (T) -> kotlin.String): kotlin.String
+public fun takeInt(/*0*/ s: kotlin.Int): kotlin.Unit
+public fun takeString(/*0*/ s: kotlin.String): kotlin.Unit
+public fun test_1(): kotlin.Unit
+public fun test_2(): kotlin.Unit
+public fun test_3(): kotlin.Unit
+public fun test_4(): kotlin.Unit
+public fun test_5(): kotlin.Unit

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestWithStdLibGenerated.java

@@ -2803,6 +2803,29 @@ public class DiagnosticsTestWithStdLibGenerated extends AbstractDiagnosticsTestW
         }
     }
 
+    @TestMetadata("compiler/testData/diagnostics/testsWithStdLib/factoryPattern")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class FactoryPattern extends AbstractDiagnosticsTestWithStdLib {
+        private void runTest(String testDataFilePath) throws Exception {
+            KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
+        }
+
+        public void testAllFilesPresentInFactoryPattern() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/testsWithStdLib/factoryPattern"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+        }
+
+        @TestMetadata("overloadByLambdaReturnType_disabled.kt")
+        public void testOverloadByLambdaReturnType_disabled() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_disabled.kt");
+        }
+
+        @TestMetadata("overloadByLambdaReturnType_enabled.kt")
+        public void testOverloadByLambdaReturnType_enabled() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_enabled.kt");
+        }
+    }
+
     @TestMetadata("compiler/testData/diagnostics/testsWithStdLib/forInArrayLoop")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsTestWithStdLibUsingJavacGenerated.java

@@ -2803,6 +2803,29 @@ public class DiagnosticsTestWithStdLibUsingJavacGenerated extends AbstractDiagno
         }
     }
 
+    @TestMetadata("compiler/testData/diagnostics/testsWithStdLib/factoryPattern")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class FactoryPattern extends AbstractDiagnosticsTestWithStdLibUsingJavac {
+        private void runTest(String testDataFilePath) throws Exception {
+            KotlinTestUtils.runTest(this::doTest, this, testDataFilePath);
+        }
+
+        public void testAllFilesPresentInFactoryPattern() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/diagnostics/testsWithStdLib/factoryPattern"), Pattern.compile("^(.+)\\.kt$"), Pattern.compile("^(.+)\\.fir\\.kts?$"), true);
+        }
+
+        @TestMetadata("overloadByLambdaReturnType_disabled.kt")
+        public void testOverloadByLambdaReturnType_disabled() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_disabled.kt");
+        }
+
+        @TestMetadata("overloadByLambdaReturnType_enabled.kt")
+        public void testOverloadByLambdaReturnType_enabled() throws Exception {
+            runTest("compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_enabled.kt");
+        }
+    }
+
     @TestMetadata("compiler/testData/diagnostics/testsWithStdLib/forInArrayLoop")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -153,6 +153,7 @@ enum class LanguageFeature(
     FunctionReferenceWithDefaultValueAsOtherType(sinceVersion = KOTLIN_1_4),
     NonStrictOnlyInputTypesChecks(sinceVersion = KOTLIN_1_4),
     SuspendConversion(sinceVersion = KOTLIN_1_4, defaultState = State.DISABLED),
+    FactoryPatternResolution(sinceVersion = KOTLIN_1_4),
 
     BooleanElvisBoundSmartCasts(sinceVersion = KOTLIN_1_3, defaultState = State.DISABLED), // see KT-26357 for details
     NewDataFlowForTryExpressions(sinceVersion = KOTLIN_1_4, defaultState = State.DISABLED),

core/util.runtime/src/org/jetbrains/kotlin/utils/addToStdlib.kt

@@ -149,3 +149,16 @@ inline fun <T, R, C : MutableCollection<in R>> Iterable<T>.flatMapToNullable(des
 
 fun <E : Enum<E>> min(a: E, b: E): E = if (a < b) a else b
 fun <E : Comparable<E>> min(a: E, b: E): E = if (a < b) a else b
+
+inline fun <T, R> Iterable<T>.same(extractor: (T) -> R): Boolean {
+    val iterator = iterator()
+    val firstValue = extractor(iterator.next())
+    while (iterator.hasNext()) {
+        val item = iterator.next()
+        val value = extractor(item)
+        if (value != firstValue) {
+            return false
+        }
+    }
+    return true
+}