diff --git a/compiler/fir/jvm/src/org/jetbrains/kotlin/fir/resolve/calls/jvm/JvmCallConflictResolverFactory.kt b/compiler/fir/jvm/src/org/jetbrains/kotlin/fir/resolve/calls/jvm/JvmCallConflictResolverFactory.kt
index e9ccd6be8d7..e9212f516f1 100644
--- a/compiler/fir/jvm/src/org/jetbrains/kotlin/fir/resolve/calls/jvm/JvmCallConflictResolverFactory.kt
+++ b/compiler/fir/jvm/src/org/jetbrains/kotlin/fir/resolve/calls/jvm/JvmCallConflictResolverFactory.kt
@@ -9,6 +9,7 @@ import org.jetbrains.kotlin.fir.NoMutableState
 import org.jetbrains.kotlin.fir.resolve.calls.ConeCallConflictResolverFactory
 import org.jetbrains.kotlin.fir.resolve.calls.ConeCompositeConflictResolver
 import org.jetbrains.kotlin.fir.resolve.calls.ConeOverloadConflictResolver
+import org.jetbrains.kotlin.fir.resolve.calls.ConeOverloadResolutionByLambdaConflictResolve
 import org.jetbrains.kotlin.fir.resolve.inference.InferenceComponents
 import org.jetbrains.kotlin.resolve.calls.results.TypeSpecificityComparator
 import org.jetbrains.kotlin.resolve.jvm.JvmTypeSpecificityComparator
@@ -22,7 +23,8 @@ object JvmCallConflictResolverFactory : ConeCallConflictResolverFactory() {
         val specificityComparator = JvmTypeSpecificityComparator(components.ctx)
         return ConeCompositeConflictResolver(
             ConeOverloadConflictResolver(specificityComparator, components),
-            ConeEquivalentCallConflictResolver(specificityComparator, components)
+            ConeEquivalentCallConflictResolver(specificityComparator, components),
+            ConeOverloadResolutionByLambdaConflictResolve(components.session),
         )
     }
 }
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeCompositeConflictResolver.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeCompositeConflictResolver.kt
index f86a3140aa8..129a3cdd6ae 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeCompositeConflictResolver.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeCompositeConflictResolver.kt
@@ -6,7 +6,7 @@
 package org.jetbrains.kotlin.fir.resolve.calls
 
 class ConeCompositeConflictResolver(
-    private vararg val conflictResolvers: AbstractConeCallConflictResolver
+    private vararg val conflictResolvers: ConeCallConflictResolver
 ) : ConeCallConflictResolver() {
     override fun chooseMaximallySpecificCandidates(
         candidates: Set<Candidate>,
@@ -22,4 +22,4 @@ class ConeCompositeConflictResolver(
         }
         return currentCandidates
     }
-}
\ No newline at end of file
+}
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeOverloadResolutionByLambdaConflictResolver.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeOverloadResolutionByLambdaConflictResolver.kt
new file mode 100644
index 00000000000..1380af0c508
--- /dev/null
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/ConeOverloadResolutionByLambdaConflictResolver.kt
@@ -0,0 +1,31 @@
+/*
+ * 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.calls
+
+import org.jetbrains.kotlin.fir.FirSession
+import org.jetbrains.kotlin.fir.declarations.FirCallableDeclaration
+import org.jetbrains.kotlin.fir.resolve.fqName
+import org.jetbrains.kotlin.resolve.descriptorUtil.OVERLOAD_RESOLUTION_BY_LAMBDA_ANNOTATION
+
+class ConeOverloadResolutionByLambdaConflictResolve(private val session: FirSession) : ConeCallConflictResolver() {
+    override fun chooseMaximallySpecificCandidates(
+        candidates: Set<Candidate>,
+        discriminateGenerics: Boolean,
+        discriminateAbstracts: Boolean
+    ): Set<Candidate> {
+        if (candidates.size == 1) return candidates
+
+        candidates.singleOrNull { candidate ->
+            (candidate.symbol.fir as? FirCallableDeclaration<*>)?.annotations?.any {
+                it.fqName(session) == OVERLOAD_RESOLUTION_BY_LAMBDA_ANNOTATION
+            } == true
+        }?.let {
+            return setOf(it)
+        }
+
+        return candidates
+    }
+}
diff --git a/compiler/testData/diagnostics/tests/callableReference/resolve/resolveTwoReferencesAgainstGenerics.fir.kt b/compiler/testData/diagnostics/tests/callableReference/resolve/resolveTwoReferencesAgainstGenerics.fir.kt
deleted file mode 100644
index 8fffcbe4ad4..00000000000
--- a/compiler/testData/diagnostics/tests/callableReference/resolve/resolveTwoReferencesAgainstGenerics.fir.kt
+++ /dev/null
@@ -1,10 +0,0 @@
-// !LANGUAGE: +NewInference
-// !DIAGNOSTICS: -UNUSED_PARAMETER
-// WITH_RUNTIME
-
-
-fun <T> List<Option<T>>.flatten(): List<T> = <!AMBIGUITY!>flatMap<!> { <!UNRESOLVED_REFERENCE!>it<!>.<!NONE_APPLICABLE!>fold<!>(::emptyList, <!UNRESOLVED_REFERENCE!>::listOf<!>) }
-
-class Option<out T> {
-    fun <R> fold(ifEmpty: () -> R, ifSome: (T) -> R): R = TODO()
-}
diff --git a/compiler/testData/diagnostics/tests/callableReference/resolve/resolveTwoReferencesAgainstGenerics.kt b/compiler/testData/diagnostics/tests/callableReference/resolve/resolveTwoReferencesAgainstGenerics.kt
index 3dcd7353331..da4dbd9b553 100644
--- a/compiler/testData/diagnostics/tests/callableReference/resolve/resolveTwoReferencesAgainstGenerics.kt
+++ b/compiler/testData/diagnostics/tests/callableReference/resolve/resolveTwoReferencesAgainstGenerics.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !LANGUAGE: +NewInference
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 // WITH_RUNTIME
diff --git a/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.fir.kt
index b69ad21f0c9..a0cf6c2b5e9 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.fir.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/coroutines/kt41430.fir.kt
@@ -3,18 +3,18 @@
 class A
 
 fun test_1(list: List<Set<A>>) {
-    list.<!AMBIGUITY!>flatMapTo<!>(mutableSetOf()) { <!UNRESOLVED_REFERENCE!>it<!> }
+    list.flatMapTo(mutableSetOf()) { it }
 }
 
 fun test_2(list: List<Set<A>>) {
     sequence<A> {
-        <!DEBUG_INFO_EXPRESSION_TYPE("ERROR CLASS: Ambiguity: flatMapTo, [kotlin/collections/flatMapTo, kotlin/collections/flatMapTo]")!>list.<!AMBIGUITY!>flatMapTo<!>(mutableSetOf()) { <!UNRESOLVED_REFERENCE!>it<!> }<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.MutableSet<A>")!>list.flatMapTo(mutableSetOf()) { it }<!>
     }
 }
 
 fun test_3(list: List<Set<A>>) {
     sequence {
-        list.<!AMBIGUITY!>flatMapTo<!>(mutableSetOf()) { <!UNRESOLVED_REFERENCE!>it<!> }
+        list.flatMapTo(mutableSetOf()) { it }
         yield(A())
     }
 }
@@ -22,6 +22,6 @@ fun test_3(list: List<Set<A>>) {
 fun test_4(list: List<Set<A>>) {
     sequence {
         yield(A())
-        list.<!AMBIGUITY!>flatMapTo<!>(mutableSetOf()) { <!UNRESOLVED_REFERENCE!>it<!> }
+        list.flatMapTo(mutableSetOf()) { it }
     }
 }
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/independentResolutionInLambda.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/independentResolutionInLambda.fir.kt
deleted file mode 100644
index de14e25943c..00000000000
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/independentResolutionInLambda.fir.kt
+++ /dev/null
@@ -1,41 +0,0 @@
-// !LANGUAGE: +NewInference +OverloadResolutionByLambdaReturnType
-// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION
-// ISSUE: KT-11265
-
-// FILE: OverloadResolutionByLambdaReturnType.kt
-
-package kotlin
-
-annotation class OverloadResolutionByLambdaReturnType
-
-// FILE: main.kt
-
-import kotlin.OverloadResolutionByLambdaReturnType
-
-@kotlin.jvm.JvmName("myFlatMapIterable")
-@OverloadResolutionByLambdaReturnType
-fun <T, R> Sequence<T>.myFlatMap(transform: (T) -> Iterable<R>): Sequence<R> {
-    TODO()
-}
-
-fun <T, R> Sequence<T>.myFlatMap(transform: (T) -> Sequence<R>): Sequence<R> {
-    TODO()
-}
-
-interface A {
-    val supertypes: Collection<B>
-}
-
-interface B {
-    val descriptors: Sequence<C>?
-}
-
-interface C
-
-fun <K : Any> elvis(x: K?, y: K): K = y
-
-fun test(a: A) {
-    a.supertypes.asSequence().<!AMBIGUITY!>myFlatMap<!> {
-        <!INAPPLICABLE_CANDIDATE!>elvis<!>(<!UNRESOLVED_REFERENCE!>it<!>.<!UNRESOLVED_REFERENCE!>descriptors<!>, sequenceOf())
-    }
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/independentResolutionInLambda.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/independentResolutionInLambda.kt
index f7fc1603694..95e2ff88ad0 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/independentResolutionInLambda.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/independentResolutionInLambda.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !LANGUAGE: +NewInference +OverloadResolutionByLambdaReturnType
 // !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION
 // ISSUE: KT-11265
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_1.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_1.fir.kt
deleted file mode 100644
index d017efdc4ba..00000000000
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_1.fir.kt
+++ /dev/null
@@ -1,35 +0,0 @@
-// !LANGUAGE: +NewInference +OverloadResolutionByLambdaReturnType
-// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION -EXPERIMENTAL_API_USAGE -EXPERIMENTAL_UNSIGNED_LITERALS
-// ISSUE: KT-11265
-
-// FILE: OverloadResolutionByLambdaReturnType.kt
-
-package kotlin
-
-annotation class OverloadResolutionByLambdaReturnType
-
-// FILE: main.kt
-
-import kotlin.OverloadResolutionByLambdaReturnType
-
-@OverloadResolutionByLambdaReturnType
-fun <R> UByteArray.fooMap(t: (UByte) -> Iterable<R>): List<R> {
-    TODO("ub.fm")
-}
-
-@OverloadResolutionByLambdaReturnType
-fun <T, R> Iterable<T>.fooMap(t: (T) -> Iterable<R>): List<R> {
-    TODO("i.fm(i)")
-}
-
-@JvmName("fooMapSeq")
-fun <T, R> Iterable<T>.fooMap(t: (T) -> Sequence<R>): List<R> {
-    TODO("i.fm(s)")
-}
-
-fun test() {
-    val list = ubyteArrayOf(0u).<!AMBIGUITY!>fooMap<!> { <!NONE_APPLICABLE!>listOf<!>(<!UNRESOLVED_REFERENCE!>it<!>) }
-    takeUByteList(list)
-}
-
-fun takeUByteList(list: List<UByte>) {}
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_1.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_1.kt
index 989ad9a96e5..485b9617821 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_1.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_1.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !LANGUAGE: +NewInference +OverloadResolutionByLambdaReturnType
 // !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION -EXPERIMENTAL_API_USAGE -EXPERIMENTAL_UNSIGNED_LITERALS
 // ISSUE: KT-11265
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_3.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_3.fir.kt
deleted file mode 100644
index c5a6b7f8778..00000000000
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_3.fir.kt
+++ /dev/null
@@ -1,54 +0,0 @@
-// !LANGUAGE: +NewInference +OverloadResolutionByLambdaReturnType
-// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION -EXPERIMENTAL_API_USAGE -EXPERIMENTAL_UNSIGNED_LITERALS
-// ISSUE: KT-11265
-
-// FILE: OverloadResolutionByLambdaReturnType.kt
-
-package kotlin
-
-annotation class OverloadResolutionByLambdaReturnType
-
-// FILE: main.kt
-
-import kotlin.OverloadResolutionByLambdaReturnType
-
-public inline fun <T, R> Iterable<T>.myFlatMap(transform: (T) -> Iterable<R>): List<R> {
-    TODO()
-}
-
-@OverloadResolutionByLambdaReturnType
-@kotlin.jvm.JvmName("myFlatMapSequence")
-public inline fun <T, R> Iterable<T>.myFlatMap(transform: (T) -> Sequence<R>): List<R> {
-    TODO()
-}
-
-interface Name
-interface DeclarationDescriptor {
-    val nextCandidates: List<DeclarationDescriptor>?
-    val nextCandidatesSeq: Sequence<DeclarationDescriptor>?
-    val name: Name
-}
-
-fun test_1(name: Name, toplevelDescriptors: List<DeclarationDescriptor>): List<DeclarationDescriptor> {
-    val candidates = toplevelDescriptors.<!AMBIGUITY!>myFlatMap<!> { container ->
-        val nextCandidates = container.<!UNRESOLVED_REFERENCE!>nextCandidates<!> ?: return@myFlatMap emptyList()
-        nextCandidates
-    }
-    return candidates
-}
-
-fun test_2(name: Name, toplevelDescriptors: List<DeclarationDescriptor>): List<DeclarationDescriptor> {
-    val candidates = toplevelDescriptors.<!AMBIGUITY!>myFlatMap<!> { container ->
-        val nextCandidates = container.<!UNRESOLVED_REFERENCE!>nextCandidatesSeq<!> ?: return@myFlatMap sequenceOf()
-        nextCandidates
-    }
-    return candidates
-}
-
-fun test_3(name: Name, toplevelDescriptors: List<DeclarationDescriptor>): List<DeclarationDescriptor> {
-    val candidates = toplevelDescriptors.<!AMBIGUITY!>myFlatMap<!> { container ->
-        val nextCandidates = container.<!UNRESOLVED_REFERENCE!>nextCandidatesSeq<!>!!
-        nextCandidates
-    }
-    return candidates
-}
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_3.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_3.kt
index 71f5bdf68e8..7e25ef482b2 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_3.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/multipleOverloads_3.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !LANGUAGE: +NewInference +OverloadResolutionByLambdaReturnType
 // !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION -EXPERIMENTAL_API_USAGE -EXPERIMENTAL_UNSIGNED_LITERALS
 // ISSUE: KT-11265
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_disabled.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_disabled.fir.kt
index edea75cb513..dd6b72a04d6 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_disabled.fir.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_disabled.fir.kt
@@ -20,17 +20,17 @@ fun takeString(s: String) {}
 fun takeInt(s: Int) {}
 
 fun test_1() {
-    val x = <!AMBIGUITY!>create<!> { "" }
+    val x = create { "" }
     takeString(x)
 }
 
 fun test_2() {
-    val x = <!AMBIGUITY!>create<!> { 1 }
-    takeInt(x)
+    val x = create { 1 }
+    <!INAPPLICABLE_CANDIDATE!>takeInt<!>(x)
 }
 
 fun test_3() {
-    val x = <!AMBIGUITY!>create<!> { 1.0 }
+    val x = create { 1.0 }
 }
 
 @OverloadResolutionByLambdaReturnType
@@ -38,11 +38,11 @@ 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<!>("") { "" }
+    val x = create("") { "" }
     takeString(x)
 }
 
 fun test_5() {
-    val x = <!AMBIGUITY!>create<!>("") { 1 }
-    takeInt(x)
-}
\ No newline at end of file
+    val x = create("") { 1 }
+    <!INAPPLICABLE_CANDIDATE!>takeInt<!>(x)
+}
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_enabled.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_enabled.fir.kt
index 2d2fbb7ce42..1fdc0004ddd 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_enabled.fir.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/overloadByLambdaReturnType_enabled.fir.kt
@@ -20,17 +20,17 @@ fun takeString(s: String) {}
 fun takeInt(s: Int) {}
 
 fun test_1() {
-    val x = <!AMBIGUITY!>create<!> { "" }
+    val x = create { "" }
     takeString(x)
 }
 
 fun test_2() {
-    val x = <!AMBIGUITY!>create<!> { 1 }
-    takeInt(x)
+    val x = create { 1 }
+    <!INAPPLICABLE_CANDIDATE!>takeInt<!>(x)
 }
 
 fun test_3() {
-    val x = <!AMBIGUITY!>create<!> { 1.0 }
+    val x = create { 1.0 }
 }
 
 @OverloadResolutionByLambdaReturnType
@@ -38,13 +38,13 @@ 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<!>("") { "" }
+    val x = create("") { "" }
     takeString(x)
 }
 
 fun test_5() {
-    val x = <!AMBIGUITY!>create<!>("") { 1 }
-    takeInt(x)
+    val x = create("") { 1 }
+    <!INAPPLICABLE_CANDIDATE!>takeInt<!>(x)
 }
 
 interface A
@@ -56,6 +56,6 @@ fun foo(f: () -> A): Int = 1
 fun foo(f: () -> B): String = ""
 
 fun test_6(c: C) {
-    val x = <!AMBIGUITY!>foo<!> { c }
+    val x = foo { c }
     takeString(x)
 }
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/resolutionInOldInference.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/resolutionInOldInference.fir.kt
deleted file mode 100644
index ea9e10330bc..00000000000
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/resolutionInOldInference.fir.kt
+++ /dev/null
@@ -1,24 +0,0 @@
-// !LANGUAGE: -NewInference
-// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION
-// ISSUE: KT-11265
-
-// FILE: OverloadResolutionByLambdaReturnType.kt
-
-package kotlin
-
-annotation class OverloadResolutionByLambdaReturnType
-
-// FILE: main.kt
-
-import kotlin.OverloadResolutionByLambdaReturnType
-
-@OverloadResolutionByLambdaReturnType
-fun create(f: (Int) -> Int): Int = 1
-fun create(f: (Int) -> String): String = ""
-
-fun takeString(s: String) {}
-
-fun test_1() {
-    val x = <!AMBIGUITY!>create<!> { "" }
-    takeString("")
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/resolutionInOldInference.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/resolutionInOldInference.kt
index 1da656d5b7c..8870c5ea0dd 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/resolutionInOldInference.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/resolutionInOldInference.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !LANGUAGE: -NewInference
 // !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE -UNUSED_EXPRESSION
 // ISSUE: KT-11265
diff --git a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/returnFromInlineLambda.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/returnFromInlineLambda.fir.kt
index ed92d7cd852..af86c7df384 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/returnFromInlineLambda.fir.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/factoryPattern/returnFromInlineLambda.fir.kt
@@ -25,10 +25,10 @@ inline fun <T, R> Array<out T>.myFlatMap(transform: (T) -> Sequence<R>): List<R>
 fun String.toList(): List<String> = null!!
 
 fun test_1(a: Array<String>, b: Boolean) {
-    a.<!AMBIGUITY!>myFlatMap<!> { <!UNRESOLVED_REFERENCE!>it<!>.toList().ifEmpty { return } }
-    a.<!AMBIGUITY!>myFlatMap<!> {
+    a.myFlatMap { it.toList().ifEmpty { return } }
+    a.myFlatMap {
         if (b) return
-        <!UNRESOLVED_REFERENCE!>it<!>.toList()
+        it.toList()
     }
 }
 
@@ -43,9 +43,9 @@ fun <T, R> Array<out T>.noInlineFlatMap(transform: (T) -> Sequence<R>): List<R>
 }
 
 fun test_2(a: Array<String>, b: Boolean) {
-    a.<!AMBIGUITY!>noInlineFlatMap<!> { <!UNRESOLVED_REFERENCE!>it<!>.toList().ifEmpty { return } }
-    a.<!AMBIGUITY!>noInlineFlatMap<!> {
+    a.noInlineFlatMap { it.toList().ifEmpty { return } }
+    a.noInlineFlatMap {
         if (b) return
-        <!UNRESOLVED_REFERENCE!>it<!>.toList()
+        it.toList()
     }
 }
diff --git a/compiler/testData/diagnostics/testsWithStdLib/when/noTypeArgumentsInConstructor.fir.kt b/compiler/testData/diagnostics/testsWithStdLib/when/noTypeArgumentsInConstructor.fir.kt
index d6bb676ce71..d3314901a7c 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/when/noTypeArgumentsInConstructor.fir.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/when/noTypeArgumentsInConstructor.fir.kt
@@ -23,21 +23,21 @@ val test3: MutableList<Int> =
         }
 
 val test4: Collection<Int> =
-        listOf(1, 2, 3).<!AMBIGUITY!>flatMapTo<!>(LinkedHashSet()) {
-            <!NONE_APPLICABLE!>listOf<!>(<!UNRESOLVED_REFERENCE!>it<!>)
+        listOf(1, 2, 3).flatMapTo(LinkedHashSet()) {
+            listOf(it)
         }
 
 val test5: Collection<Int> =
-        listOf(1, 2, 3).<!AMBIGUITY!>flatMapTo<!>(LinkedHashSet()) { // TODO
-            if (true) <!NONE_APPLICABLE!>listOf<!>(<!UNRESOLVED_REFERENCE!>it<!>) else <!NONE_APPLICABLE!>listOf<!>(<!UNRESOLVED_REFERENCE!>it<!>)
+        listOf(1, 2, 3).flatMapTo(LinkedHashSet()) { // TODO
+            if (true) listOf(it) else listOf(it)
         }
 
 val test6: Collection<Int> =
-        listOf(1, 2, 3).<!AMBIGUITY!>flatMapTo<!>(LinkedHashSet<Int>()) {
-            if (true) <!NONE_APPLICABLE!>listOf<!>(<!UNRESOLVED_REFERENCE!>it<!>) else <!NONE_APPLICABLE!>listOf<!>(<!UNRESOLVED_REFERENCE!>it<!>)
+        listOf(1, 2, 3).flatMapTo(LinkedHashSet<Int>()) {
+            if (true) listOf(it) else listOf(it)
         }
 
 val test7: Collection<Int> =
-        listOf(1, 2, 3).<!AMBIGUITY!>flatMapTo<!>(LinkedHashSet()) {
-            <!INAPPLICABLE_CANDIDATE!>select<!>(<!NONE_APPLICABLE!>listOf<!>(<!UNRESOLVED_REFERENCE!>it<!>), <!NONE_APPLICABLE!>listOf<!>(<!UNRESOLVED_REFERENCE!>it<!>))
+        listOf(1, 2, 3).flatMapTo(LinkedHashSet()) {
+            select(listOf(it), listOf(it))
         }
diff --git a/compiler/testData/ir/irText/regressions/typeParametersInImplicitCast.fir.txt b/compiler/testData/ir/irText/regressions/typeParametersInImplicitCast.fir.txt
index 70025eb96c8..5dd0ad9a6f8 100644
--- a/compiler/testData/ir/irText/regressions/typeParametersInImplicitCast.fir.txt
+++ b/compiler/testData/ir/irText/regressions/typeParametersInImplicitCast.fir.txt
@@ -4,12 +4,16 @@ FILE fqName:<root> fileName:/typeParametersInImplicitCast.kt
     VALUE_PARAMETER name:lss index:0 type:kotlin.collections.List<kotlin.collections.List<T of <root>.problematic>>
     BLOCK_BODY
       RETURN type=kotlin.Nothing from='public final fun problematic <T> (lss: kotlin.collections.List<kotlin.collections.List<T of <root>.problematic>>): kotlin.collections.List<T of <root>.problematic> declared in <root>'
-        ERROR_CALL 'Unresolved reference: <Ambiguity: flatMap, [kotlin/collections/flatMap, kotlin/collections/flatMap]>#' type=IrErrorType
-          FUN_EXPR type=kotlin.Function0<kotlin.collections.List<kotlin.Any?>> origin=LAMBDA
-            FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.collections.List<kotlin.Any?>
+        CALL 'public final fun flatMap <T, R> (transform: kotlin.Function1<T of kotlin.collections.flatMap, kotlin.collections.Iterable<R of kotlin.collections.flatMap>>): kotlin.collections.List<R of kotlin.collections.flatMap> [inline] declared in kotlin.collections' type=kotlin.collections.List<T of <root>.problematic> origin=null
+          <T>: kotlin.collections.List<T of <root>.problematic>
+          <R>: T of <root>.problematic
+          $receiver: GET_VAR 'lss: kotlin.collections.List<kotlin.collections.List<T of <root>.problematic>> declared in <root>.problematic' type=kotlin.collections.List<kotlin.collections.List<T of <root>.problematic>> origin=null
+          transform: FUN_EXPR type=kotlin.Function1<kotlin.collections.List<T of <root>.problematic>, kotlin.collections.Iterable<T of <root>.problematic>> origin=LAMBDA
+            FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> (it:kotlin.collections.List<T of <root>.problematic>) returnType:kotlin.collections.Iterable<T of <root>.problematic>
+              VALUE_PARAMETER name:it index:0 type:kotlin.collections.List<T of <root>.problematic>
               BLOCK_BODY
-                RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.collections.List<kotlin.Any?> declared in <root>.problematic'
-                  TYPE_OP type=kotlin.collections.List<kotlin.Any?> origin=IMPLICIT_NOTNULL typeOperand=kotlin.collections.List<kotlin.Any?>
-                    CALL 'public/*package*/ open fun id <T> (v: kotlin.collections.List<T of <root>.ListId.id?>?): kotlin.collections.List<T of <root>.ListId.id?> declared in <root>.ListId' type=kotlin.collections.List<kotlin.Any?> origin=null
-                      <T>: kotlin.Any?
-                      v: ERROR_CALL 'Unresolved reference: <Unresolved name: it>#' type=IrErrorType
+                RETURN type=kotlin.Nothing from='local final fun <anonymous> (it: kotlin.collections.List<T of <root>.problematic>): kotlin.collections.Iterable<T of <root>.problematic> declared in <root>.problematic'
+                  TYPE_OP type=kotlin.collections.List<T of <root>.problematic?> origin=IMPLICIT_NOTNULL typeOperand=kotlin.collections.List<T of <root>.problematic?>
+                    CALL 'public/*package*/ open fun id <T> (v: kotlin.collections.List<T of <root>.ListId.id?>?): kotlin.collections.List<T of <root>.ListId.id?> declared in <root>.ListId' type=kotlin.collections.List<T of <root>.problematic?> origin=null
+                      <T>: T of <root>.problematic?
+                      v: GET_VAR 'it: kotlin.collections.List<T of <root>.problematic> declared in <root>.problematic.<anonymous>' type=kotlin.collections.List<T of <root>.problematic> origin=null