diff --git a/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestGenerated.java
index d1c0b5880c9..0b22a318dbd 100644
--- a/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/resolve/tests/org/jetbrains/kotlin/fir/FirOldFrontendDiagnosticsTestGenerated.java
@@ -11196,6 +11196,16 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirOldFronte
                 runTest("compiler/testData/diagnostics/tests/inference/upperBounds/doNotInferFromBoundsOnly.kt");
             }
 
+            @TestMetadata("flexibilityInCommonSuperTypeCalculation.kt")
+            public void testFlexibilityInCommonSuperTypeCalculation() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.kt");
+            }
+
+            @TestMetadata("flexibilityInCommonSuperTypeCalculation.ni.kt")
+            public void testFlexibilityInCommonSuperTypeCalculation_ni() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.ni.kt");
+            }
+
             @TestMetadata("intersectUpperBounds.kt")
             public void testIntersectUpperBounds() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inference/upperBounds/intersectUpperBounds.kt");
diff --git a/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/NewCommonSuperTypeCalculator.kt b/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/NewCommonSuperTypeCalculator.kt
index 2ec2cbb7336..d0e41539851 100644
--- a/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/NewCommonSuperTypeCalculator.kt
+++ b/compiler/resolution/src/org/jetbrains/kotlin/resolve/calls/NewCommonSuperTypeCalculator.kt
@@ -16,11 +16,9 @@
 
 package org.jetbrains.kotlin.resolve.calls
 
-import org.jetbrains.kotlin.types.AbstractNullabilityChecker
+import org.jetbrains.kotlin.types.*
+import org.jetbrains.kotlin.types.AbstractFlexibilityChecker.hasDifferentFlexibilityAtDepth
 import org.jetbrains.kotlin.types.AbstractNullabilityChecker.hasPathByNotMarkedNullableNodes
-import org.jetbrains.kotlin.types.AbstractTypeChecker
-import org.jetbrains.kotlin.types.AbstractTypeCheckerContext
-import org.jetbrains.kotlin.types.UnwrappedType
 import org.jetbrains.kotlin.types.checker.SimpleClassicTypeSystemContext
 import org.jetbrains.kotlin.types.model.*
 
@@ -32,10 +30,14 @@ object NewCommonSuperTypeCalculator {
 
     fun TypeSystemCommonSuperTypesContext.commonSuperType(types: List<KotlinTypeMarker>): KotlinTypeMarker {
         val maxDepth = types.maxBy { it.typeDepth() }?.typeDepth() ?: 0
-        return commonSuperType(types, -maxDepth)
+        return commonSuperType(types, -maxDepth, true)
     }
 
-    private fun TypeSystemCommonSuperTypesContext.commonSuperType(types: List<KotlinTypeMarker>, depth: Int): KotlinTypeMarker {
+    private fun TypeSystemCommonSuperTypesContext.commonSuperType(
+        types: List<KotlinTypeMarker>,
+        depth: Int,
+        isTopLevelType: Boolean = false
+    ): KotlinTypeMarker {
         if (types.isEmpty()) throw IllegalStateException("Empty collection for input")
 
         types.singleOrNull()?.let { return it }
@@ -69,6 +71,22 @@ object NewCommonSuperTypeCalculator {
         val upperSuperType = commonSuperTypeForSimpleTypes(
             types.map { it.upperBoundIfFlexible() }, depth, contextStubTypesEqualToAnything, contextStubTypesNotEqual
         )
+
+        if (!isTopLevelType) {
+            val nonStubTypes =
+                types.filter { !isStubRelatedType(it.lowerBoundIfFlexible()) && !isStubRelatedType(it.upperBoundIfFlexible()) }
+            val equalToEachOtherTypes = nonStubTypes.filter { potentialCommonSuperType ->
+                nonStubTypes.all {
+                    AbstractTypeChecker.equalTypes(this, it, potentialCommonSuperType)
+                }
+            }
+
+            if (equalToEachOtherTypes.isNotEmpty()) {
+                // TODO: merge flexibilities of type arguments instead of select the first suitable type
+                return equalToEachOtherTypes.first()
+            }
+        }
+
         return createFlexibleType(lowerSuperType, upperSuperType)
     }
 
@@ -109,8 +127,10 @@ object NewCommonSuperTypeCalculator {
         val uniqueTypes = arrayListOf<SimpleTypeMarker>()
         for (type in types) {
             val isNewUniqueType = uniqueTypes.all {
-                !AbstractTypeChecker.equalTypes(contextStubTypesNotEqual, it, type) ||
-                        it.typeConstructor().isIntegerLiteralTypeConstructor()
+                val equalsModuloFlexibility = AbstractTypeChecker.equalTypes(contextStubTypesNotEqual, it, type) &&
+                        !it.typeConstructor().isIntegerLiteralTypeConstructor()
+
+                !equalsModuloFlexibility || hasDifferentFlexibilityAtDepth(listOf(it, type))
             }
             if (isNewUniqueType) {
                 uniqueTypes += type
@@ -121,7 +141,7 @@ object NewCommonSuperTypeCalculator {
 
     // This function leaves only supertypes, i.e. A0 is a strong supertype for A iff A != A0 && A <: A0
     // Explanation: consider types (A : A0, B : B0, A0, B0), then CST(A, B, A0, B0) == CST(CST(A, A0), CST(B, B0)) == CST(A0, B0)
-    private fun filterSupertypes(
+    private fun TypeSystemCommonSuperTypesContext.filterSupertypes(
         list: List<SimpleTypeMarker>,
         contextStubTypesNotEqual: AbstractTypeCheckerContext
     ): List<SimpleTypeMarker> {
@@ -130,7 +150,9 @@ object NewCommonSuperTypeCalculator {
         while (iterator.hasNext()) {
             val potentialSubtype = iterator.next()
             val isSubtype = supertypes.any { supertype ->
-                supertype !== potentialSubtype && AbstractTypeChecker.isSubtypeOf(contextStubTypesNotEqual, potentialSubtype, supertype)
+                supertype !== potentialSubtype &&
+                        AbstractTypeChecker.isSubtypeOf(contextStubTypesNotEqual, potentialSubtype, supertype) &&
+                        !hasDifferentFlexibilityAtDepth(listOf(potentialSubtype, supertype))
             }
 
             if (isSubtype) iterator.remove()
@@ -352,14 +374,26 @@ object NewCommonSuperTypeCalculator {
         // CS(Out<X>, Out<Y>) = Out<CS(X, Y)>
         // CS(In<X>, In<Y>) = In<X & Y>
         if (asOut) {
-            val type = commonSuperType(arguments.map { it.getType() }, depth + 1)
-            return if (parameter.getVariance() != TypeVariance.INV) return type.asTypeArgument() else createTypeArgument(
-                type,
-                TypeVariance.OUT
-            )
+            val argumentTypes = arguments.map { it.getType() }
+            val parameterIsNotInv = parameter.getVariance() != TypeVariance.INV
+
+            if (parameterIsNotInv) {
+                return commonSuperType(argumentTypes, depth + 1).asTypeArgument()
+            }
+
+            val equalToEachOtherType = arguments.firstOrNull { potentialSuperType ->
+                arguments.all { AbstractTypeChecker.equalTypes(this, it.getType(), potentialSuperType.getType()) }
+            }
+
+            return if (equalToEachOtherType == null) {
+                createTypeArgument(commonSuperType(argumentTypes, depth + 1), TypeVariance.OUT)
+            } else {
+                createTypeArgument(equalToEachOtherType.getType(), TypeVariance.INV)
+            }
         } else {
             val type = intersectTypes(arguments.map { it.getType() })
-            return if (parameter.getVariance() != TypeVariance.INV) return type.asTypeArgument() else createTypeArgument(
+
+            return if (parameter.getVariance() != TypeVariance.INV) type.asTypeArgument() else createTypeArgument(
                 type,
                 TypeVariance.IN
             )
diff --git a/compiler/testData/diagnostics/tests/inference/commonSystem/nonFixedVariableFromBothBranches.kt b/compiler/testData/diagnostics/tests/inference/commonSystem/nonFixedVariableFromBothBranches.kt
index 3b672bd96c7..03de747369f 100644
--- a/compiler/testData/diagnostics/tests/inference/commonSystem/nonFixedVariableFromBothBranches.kt
+++ b/compiler/testData/diagnostics/tests/inference/commonSystem/nonFixedVariableFromBothBranches.kt
@@ -16,5 +16,5 @@ fun <R> foo(f: () -> R): R = f()
 fun test(n: Number) {
     val a = select(foo { JavaTest.createNumberArray() }, emptyArray())
 
-    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.Array<(kotlin.Number..kotlin.Number?)>..kotlin.Array<out (kotlin.Number..kotlin.Number?)>?)")!>a<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.Array<(kotlin.Number..kotlin.Number?)>..kotlin.Array<(kotlin.Number..kotlin.Number?)>?)")!>a<!>
 }
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.fir.kt b/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.fir.kt
new file mode 100644
index 00000000000..38ae04e2545
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.fir.kt
@@ -0,0 +1,273 @@
+// !DIAGNOSTICS: -UNSUPPORTED -UNUSED_EXPRESSION -DEBUG_INFO_SMARTCAST -USELESS_CAST -UNUSED_PARAMETER -UNCHECKED_CAST -CAST_NEVER_SUCCEEDS -UNUSED_VARIABLE -UNREACHABLE_CODE -DEBUG_INFO_CONSTANT
+// !LANGUAGE: -NewInference
+// SKIP_TXT
+
+// FILE: Test.java
+import java.util.List;
+
+public class Test {
+    public static B foo() { return null; }
+    public static <T> T bar() { return null; }
+    public static <T> T id(T x) { return null; }
+    public static <T> List<T> getList(T x) { return null; }
+    public static List getRawList() { return null; }
+}
+
+// FILE: main.kt
+class A<T>(x: T)
+class B
+
+fun <T> select(vararg x: T): T = null as T
+
+fun case_1() {
+    val x = Test.foo() // B!
+
+    val result_1 = select(A(x), A(B()))
+    val result_2 = select(A(B()), A(x), A(if (true) B() else null))
+    val result_3 = select(A(x), A(if (true) B() else null))
+
+    result_1
+    result_2
+    result_3
+}
+
+fun case_2() {
+    val x = Test.bar<Any>() // Any!
+    val y: Any? = null
+
+    val result = select(A(Any()), A(y), A(x))
+
+    result
+}
+
+fun <T> case_3() {
+    val x = Test.bar<T>() // T!
+    val y: T? = null
+    val result = select(A(y), A(x), A(null as T))
+
+    result
+}
+
+fun case_4() {
+    val x = Test.bar<Nothing>() // Nothing!
+    val y = null // Nothing?
+
+    val result = select(A(x), A(y), A(return))
+
+    result
+}
+
+class C<T, K, L>(x: T, y: K, z: L)
+
+fun case_5() {
+    val x = Test.foo() // B!
+    val y: B? = null
+
+    val result_1 = select(C(x, B(), 10), C(B(), x, 10))
+    val result_2 = select(C(B(), x, y), C(x, B(), y), C(y, x, B()), C(x, y, B()), C(y, B(), x), C(B(), y, x))
+
+    result_1
+    result_2
+}
+
+fun case_6() {
+    val x1 = Test.bar<C<C<A<Float>, B, Int>, B, B>>() // C<C<A<Float>, B, Int>, B, B>!
+    val x2 = C(null as C<A<Float?>, B?, Int>?, Test.id(B()), B()) // C<C<A<Float?>, B?, Int>?, B?, B>
+    val x3 = C(C(A(Test.id(1f)), B(), Test.id(1)), Test.id(B()), B()) // C<C<A<Float!>, B, Int!>, B!, B>
+    val x4 = C(C(A(Test.id(3f)), null as B?, null as Int?), null as B?, null as B?) // C<C<A<Float?>?, B?, Int?>, B?, B?>
+    val x5 = C(Test.id(C(A(1f), Test.id(B()), 1)), B(), Test.id(B())) // C<C<A<Float>, B!, Int>!, B, B!>
+    val x6 = Test.id(C(select(C(Test.id(A(1f)), null as B?, null as Int?), null), Test.id(B()), null as B?)) // C<C<A<Float!>, B?, Int?>?, B!, B?>!
+    val x7 = C(C(Test.id(A(1f)), B(), 1), B(), B()) // C<C<A<Float>!, B, Int>, B, B>
+    val x8 = C(Test.id(C(null as A<Float?>?, B(), null as Int?)), null as B?, Test.id(B())) // C<C<A<Float?>?, B, Int?>, B?, B>
+    val x9 = null as C<C<A<Float>, B?, Int>, B, B>? // C<C<A<Float>, B?, Int>, B, B>?
+
+    val result_1 = select(x1, x2, x3, x4, x5, x6, x7, x8, x9)
+    val result_2 = select(x9, x8, x7, x6, x5, x4, x3, x2, x1)
+    val result_3 = select(x5, x7, x9, x3, x1, x2, x8, x4, x6)
+
+    result_1
+    result_2
+    result_3
+}
+
+fun case_7() {
+    val x0: Int = 1
+    val x1 = C(A(Test.id(x0)), B(), B())
+    val x2 = C(Test.id(A(1)), B(), B())
+    x1
+    x2
+
+    val result_5 = select(x1, x2)
+    result_5
+}
+
+fun case_8() {
+    val x1 = A(10)
+    val x2 = select(A(""), null)
+    val x3 = Test.id(A(null))
+
+    val result_1 = select(x1, x2, x3)
+    result_1
+}
+
+fun case_9() {
+    val x1 = A(A(10))
+    val x2 = A(select(A(""), null))
+    val x3 = A(Test.id(A('s')))
+
+    val result_1 = select(x1, x2, x3)
+    result_1
+}
+
+fun case_10() {
+    val x1 = 10
+    val x2 = select(10, null)
+    val x3 = Test.id(10)
+
+    val result_1 = select(x2, x1, x3)
+    val result_2 = select(x2, x3, x1)
+    val result_3 = select(x1, x2, x3)
+    val result_4 = select(x1, x3, x2)
+    val result_5 = select(x3, x2, x1)
+    val result_6 = select(x3, x1, x2)
+
+    result_1
+    result_2
+    result_3
+    result_4
+    result_5
+    result_6
+}
+
+fun <T> case_11(y: T) {
+    val x1 = Test.bar<T>() // T!
+    val x2 = select(y, null)
+    if (y != null) {
+        val x3 = Test.id(y) // T!
+        val result_1 = select(A(y), A(x1))
+        val result_2 = select(A(y), A(x1), A(x2))
+        val result_3 = select(A(y), A(x3), A(x2))
+        val result_4 = select(A(y as T), A(x1))
+        val result_5 = select(A(y as T), A(x1), A(x2))
+        val result_6 = select(A(y as T), A(x3), A(x2))
+        val result_7 = select(A(y as T), A(x1))
+        val result_8 = select(A(y as T), A(x3))
+        val result_9 = select(A(x3), A(y as T))
+
+        val result_10 = select(y, x1)
+        val result_11 = select(y, x2, x2)
+        val result_12 = select(y, x3, x2)
+        val result_13 = select(y as T, x1)
+        val result_14 = select(y as T, x1, x2)
+        val result_15 = select(y as T, x3, x2)
+        val result_16 = select(y as T, x1)
+        val result_17 = select(y as T, x3)
+        val result_18 = select(x3, y as T)
+
+        x1
+        x2
+        x3
+        y
+
+        result_1
+        result_2
+        result_3
+        result_4
+        result_5
+        result_6
+        result_7
+        result_8
+        result_9
+
+        result_10
+        result_11
+        result_12
+        result_13
+        result_14
+        result_15
+        result_16
+        result_17
+        result_18
+    }
+}
+
+fun case_12() {
+    val x1 = Test.getList(10)
+    val x2 = null as MutableList<Int>
+    val x3 = select(null as List<Int>, null)
+
+    val result_1 = select(x1, x2)
+    val result_2 = select(x2, x1)
+    val result_3 = select(x2, x1, x3)
+    val result_4 = select(x3, x1)
+    val result_5 = select(A(x1), A(x2))
+    val result_6 = select(A(x2), A(x1))
+    val result_7 = select(A(x3), A(x1), A(x2))
+    val result_8 = select(A(x1), A(x3))
+
+    result_1
+    result_2
+    result_3
+    result_4
+    result_5
+    result_6
+    result_7
+    result_8
+}
+
+fun case_13() {
+    val x1 = Test.getList(10)
+    val x2: dynamic = null
+    val x3 = null as MutableList<Int>
+    val x4 = select(null as List<Int>, null)
+
+    val result_1 = <!INAPPLICABLE_CANDIDATE!>select<!>(x1, x2, x3, x4)
+    val result_2 = <!INAPPLICABLE_CANDIDATE!>select<!>(x2, x1)
+    val result_3 = <!INAPPLICABLE_CANDIDATE!>select<!>(x2, x1, x3)
+    val result_4 = <!INAPPLICABLE_CANDIDATE!>select<!>(x3, x2)
+    val result_5 = <!INAPPLICABLE_CANDIDATE!>select<!>(x4, x2)
+    val result_6 = <!INAPPLICABLE_CANDIDATE!>select<!>(x4, x3, x2)
+    val result_7 = <!INAPPLICABLE_CANDIDATE!>select<!>(A(x1), <!INAPPLICABLE_CANDIDATE!>A<!>(x2), A(x3), A(x4))
+    val result_8 = <!INAPPLICABLE_CANDIDATE!>select<!>(<!INAPPLICABLE_CANDIDATE!>A<!>(x2), A(x1))
+    val result_9 = <!INAPPLICABLE_CANDIDATE!>select<!>(<!INAPPLICABLE_CANDIDATE!>A<!>(x2), A(x1), A(x3))
+    val result_10 = <!INAPPLICABLE_CANDIDATE!>select<!>(A(x3), <!INAPPLICABLE_CANDIDATE!>A<!>(x2))
+    val result_11 = <!INAPPLICABLE_CANDIDATE!>select<!>(A(x4), <!INAPPLICABLE_CANDIDATE!>A<!>(x2))
+    val result_12 = <!INAPPLICABLE_CANDIDATE!>select<!>(A(x4), A(x3), <!INAPPLICABLE_CANDIDATE!>A<!>(x2))
+
+    result_1
+    result_2
+    result_3
+    result_4
+    result_5
+    result_6
+    result_7
+    result_8
+    result_9
+    result_10
+    result_11
+    result_12
+}
+
+fun case_14() {
+    val x1 = Test.getRawList()
+    val x2 = null as List<Int>
+    val x3 = select(null as MutableList<Int>, null)
+
+    val result_1 = select(x1, x2)
+    val result_2 = select(x2, x1)
+    val result_3 = select(x2, x1, x3)
+    val result_4 = select(x3, x1)
+    val result_5 = select(A(x1), A(x2))
+    val result_6 = select(A(x2), A(x1))
+    val result_7 = select(A(x3), A(x1), A(x2))
+    val result_8 = select(A(x1), A(x3))
+
+    result_1
+    result_2
+    result_3
+    result_4
+    result_5
+    result_6
+    result_7
+    result_8
+}
diff --git a/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.kt b/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.kt
new file mode 100644
index 00000000000..22ea1790c38
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.kt
@@ -0,0 +1,273 @@
+// !DIAGNOSTICS: -UNSUPPORTED -UNUSED_EXPRESSION -DEBUG_INFO_SMARTCAST -USELESS_CAST -UNUSED_PARAMETER -UNCHECKED_CAST -CAST_NEVER_SUCCEEDS -UNUSED_VARIABLE -UNREACHABLE_CODE -DEBUG_INFO_CONSTANT
+// !LANGUAGE: -NewInference
+// SKIP_TXT
+
+// FILE: Test.java
+import java.util.List;
+
+public class Test {
+    public static B foo() { return null; }
+    public static <T> T bar() { return null; }
+    public static <T> T id(T x) { return null; }
+    public static <T> List<T> getList(T x) { return null; }
+    public static List getRawList() { return null; }
+}
+
+// FILE: main.kt
+class A<T>(x: T)
+class B
+
+fun <T> select(vararg x: T): T = null as T
+
+fun case_1() {
+    val x = Test.foo() // B!
+
+    val result_1 = select(A(x), A(B()))
+    val result_2 = select(A(B()), A(x), A(if (true) B() else null))
+    val result_3 = select(A(x), A(if (true) B() else null))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(B..B?)>")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(B..B?)>")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(B..B?)>")!>result_3<!>
+}
+
+fun case_2() {
+    val x = Test.bar<Any>() // Any!
+    val y: Any? = null
+
+    val result = select(A(Any()), A(y), A(x))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.Any..kotlin.Any?)>")!>result<!>
+}
+
+fun <T> case_3() {
+    val x = Test.bar<T>() // T!
+    val y: T? = null
+    val result = select(A(y), A(x), A(null as T))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(T..T?)>")!>result<!>
+}
+
+fun case_4() {
+    val x = Test.bar<Nothing>() // Nothing!
+    val y = null // Nothing?
+
+    val result = select(A(x), A(y), A(return))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.Nothing..kotlin.Nothing?)>")!>result<!>
+}
+
+class C<T, K, L>(x: T, y: K, z: L)
+
+fun case_5() {
+    val x = Test.foo() // B!
+    val y: B? = null
+
+    val result_1 = select(C(x, B(), 10), C(B(), x, 10))
+    val result_2 = select(C(B(), x, y), C(x, B(), y), C(y, x, B()), C(x, y, B()), C(y, B(), x), C(B(), y, x))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<(B..B?), B, kotlin.Int>")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<(B..B?), (B..B?), (B..B?)>")!>result_2<!>
+}
+
+fun case_6() {
+    val x1 = Test.bar<C<C<A<Float>, B, Int>, B, B>>() // C<C<A<Float>, B, Int>, B, B>!
+    val x2 = C(null as C<A<Float?>, B?, Int>?, Test.id(B()), B()) // C<C<A<Float?>, B?, Int>?, B?, B>
+    val x3 = C(C(A(Test.id(1f)), B(), Test.id(1)), Test.id(B()), B()) // C<C<A<Float!>, B, Int!>, B!, B>
+    val x4 = C(C(A(Test.id(3f)), null as B?, null as Int?), null as B?, null as B?) // C<C<A<Float?>?, B?, Int?>, B?, B?>
+    val x5 = C(Test.id(C(A(1f), Test.id(B()), 1)), B(), Test.id(B())) // C<C<A<Float>, B!, Int>!, B, B!>
+    val x6 = Test.id(C(select(C(Test.id(A(1f)), null as B?, null as Int?), null), Test.id(B()), null as B?)) // C<C<A<Float!>, B?, Int?>?, B!, B?>!
+    val x7 = C(C(Test.id(A(1f)), B(), 1), B(), B()) // C<C<A<Float>!, B, Int>, B, B>
+    val x8 = C(Test.id(C(null as A<Float?>?, B(), null as Int?)), null as B?, Test.id(B())) // C<C<A<Float?>?, B, Int?>, B?, B>
+    val x9 = null as C<C<A<Float>, B?, Int>, B, B>? // C<C<A<Float>, B?, Int>, B, B>?
+
+    val result_1 = select(x1, x2, x3, x4, x5, x6, x7, x8, x9)
+    val result_2 = select(x9, x8, x7, x6, x5, x4, x3, x2, x1)
+    val result_3 = select(x5, x7, x9, x3, x1, x2, x8, x4, x6)
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<out C<out A<(kotlin.Float..kotlin.Float?)>?, (B..B?), (kotlin.Int..kotlin.Int?)>?, (B..B?), (B..B?)>?")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<out C<out A<(kotlin.Float..kotlin.Float?)>?, (B..B?), (kotlin.Int..kotlin.Int?)>?, (B..B?), (B..B?)>?")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<out C<out A<(kotlin.Float..kotlin.Float?)>?, (B..B?), (kotlin.Int..kotlin.Int?)>?, (B..B?), (B..B?)>?")!>result_3<!>
+}
+
+fun case_7() {
+    val x0: Int = 1
+    val x1 = C(A(Test.id(x0)), B(), B())
+    val x2 = C(Test.id(A(1)), B(), B())
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<A<(kotlin.Int..kotlin.Int?)>, B, B>")!>x1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<(A<kotlin.Int>..A<kotlin.Int>?), B, B>")!>x2<!>
+
+    val result_5 = select(x1, x2)
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<A<(kotlin.Int..kotlin.Int?)>, B, B>")!>result_5<!>
+}
+
+fun case_8() {
+    val x1 = A(10)
+    val x2 = select(A(""), null)
+    val x3 = Test.id(A(null))
+
+    val result_1 = select(x1, x2, x3)
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out kotlin.Any?>?")!>result_1<!>
+}
+
+fun case_9() {
+    val x1 = A(A(10))
+    val x2 = A(select(A(""), null))
+    val x3 = A(Test.id(A('s')))
+
+    val result_1 = select(x1, x2, x3)
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out A<out kotlin.Any>?>")!>result_1<!>
+}
+
+fun case_10() {
+    val x1 = 10
+    val x2 = select(10, null)
+    val x3 = Test.id(10)
+
+    val result_1 = select(x2, x1, x3)
+    val result_2 = select(x2, x3, x1)
+    val result_3 = select(x1, x2, x3)
+    val result_4 = select(x1, x3, x2)
+    val result_5 = select(x3, x2, x1)
+    val result_6 = select(x3, x1, x2)
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_3<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_4<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_5<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_6<!>
+}
+
+fun <T> case_11(y: T) {
+    val x1 = Test.bar<T>() // T!
+    val x2 = select(y, null)
+    if (y != null) {
+        val x3 = Test.id(y) // T!
+        val result_1 = select(A(y), A(x1))
+        val result_2 = select(A(y), A(x1), A(x2))
+        val result_3 = select(A(y), A(x3), A(x2))
+        val result_4 = select(A(y as T), A(x1))
+        val result_5 = select(A(y as T), A(x1), A(x2))
+        val result_6 = select(A(y as T), A(x3), A(x2))
+        val result_7 = select(A(y as T), A(x1))
+        val result_8 = select(A(y as T), A(x3))
+        val result_9 = select(A(x3), A(y as T))
+
+        val result_10 = select(y, x1)
+        val result_11 = select(y, x2, x2)
+        val result_12 = select(y, x3, x2)
+        val result_13 = select(y as T, x1)
+        val result_14 = select(y as T, x1, x2)
+        val result_15 = select(y as T, x3, x2)
+        val result_16 = select(y as T, x1)
+        val result_17 = select(y as T, x3)
+        val result_18 = select(x3, y as T)
+
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>x1<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>x2<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>x3<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T")!>y<!>
+
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<T>")!>result_1<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<(T..T?)>")!>result_2<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<(T..T?)>")!>result_3<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<T>")!>result_4<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<(T..T?)>")!>result_5<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<(T..T?)>")!>result_6<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<T>")!>result_7<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<T>")!>result_8<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<(T..T?)>")!>result_9<!>
+
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>result_10<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>result_11<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>result_12<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>result_13<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>result_14<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>result_15<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>result_16<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>result_17<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>result_18<!>
+    }
+}
+
+fun case_12() {
+    val x1 = Test.getList(10)
+    val x2 = null as MutableList<Int>
+    val x3 = select(null as List<Int>, null)
+
+    val result_1 = select(x1, x2)
+    val result_2 = select(x2, x1)
+    val result_3 = select(x2, x1, x3)
+    val result_4 = select(x3, x1)
+    val result_5 = select(A(x1), A(x2))
+    val result_6 = select(A(x2), A(x1))
+    val result_7 = select(A(x3), A(x1), A(x2))
+    val result_8 = select(A(x1), A(x3))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.MutableList<(kotlin.Int..kotlin.Int?)>..kotlin.collections.List<(kotlin.Int..kotlin.Int?)>?)")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.MutableList<kotlin.Int>..kotlin.collections.List<kotlin.Int>?)")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.List<kotlin.Int>?")!>result_3<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.List<kotlin.Int>?")!>result_4<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.collections.MutableList<(kotlin.Int..kotlin.Int?)>..kotlin.collections.List<(kotlin.Int..kotlin.Int?)>?)>")!>result_5<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<kotlin.collections.MutableList<kotlin.Int>>")!>result_6<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.collections.MutableList<(kotlin.Int..kotlin.Int?)>..kotlin.collections.List<(kotlin.Int..kotlin.Int?)>?)>")!>result_7<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.collections.MutableList<(kotlin.Int..kotlin.Int?)>..kotlin.collections.List<(kotlin.Int..kotlin.Int?)>?)>")!>result_8<!>
+}
+
+fun case_13() {
+    val x1 = Test.getList(10)
+    val x2: dynamic = null
+    val x3 = null as MutableList<Int>
+    val x4 = select(null as List<Int>, null)
+
+    val result_1 = select(x1, x2, x3, x4)
+    val result_2 = select(x2, x1)
+    val result_3 = select(x2, x1, x3)
+    val result_4 = select(x3, x2)
+    val result_5 = select(x4, x2)
+    val result_6 = select(x4, x3, x2)
+    val result_7 = select(A(x1), A(x2), A(x3), A(x4))
+    val result_8 = select(A(x2), A(x1))
+    val result_9 = select(A(x2), A(x1), A(x3))
+    val result_10 = select(A(x3), A(x2))
+    val result_11 = select(A(x4), A(x2))
+    val result_12 = select(A(x4), A(x3), A(x2))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_3<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_4<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_5<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_6<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.collections.MutableList<(kotlin.Int..kotlin.Int?)>..kotlin.collections.List<(kotlin.Int..kotlin.Int?)>?)>")!>result_7<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<dynamic>")!>result_8<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<dynamic>")!>result_9<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<kotlin.collections.MutableList<kotlin.Int>>")!>result_10<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<kotlin.collections.List<kotlin.Int>?>")!>result_11<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<dynamic>")!>result_12<!>
+}
+
+fun case_14() {
+    val x1 = Test.getRawList()
+    val x2 = null as List<Int>
+    val x3 = select(null as MutableList<Int>, null)
+
+    val result_1 = select(x1, x2)
+    val result_2 = select(x2, x1)
+    val result_3 = select(x2, x1, x3)
+    val result_4 = select(x3, x1)
+    val result_5 = select(A(x1), A(x2))
+    val result_6 = select(A(x2), A(x1))
+    val result_7 = select(A(x3), A(x1), A(x2))
+    val result_8 = select(A(x1), A(x3))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.List<kotlin.Any?>..kotlin.collections.List<kotlin.Any?>?)")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.List<kotlin.Any?>..kotlin.collections.List<kotlin.Any?>?)")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.List<kotlin.Any?>?")!>result_3<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.MutableList<out kotlin.Any?>?..kotlin.collections.List<kotlin.Any?>?)")!>result_4<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out (kotlin.collections.List<kotlin.Any?>..kotlin.collections.List<kotlin.Any?>?)>")!>result_5<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out (kotlin.collections.List<kotlin.Any?>..kotlin.collections.List<kotlin.Any?>?)>")!>result_6<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out kotlin.collections.List<kotlin.Any?>?>")!>result_7<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out (kotlin.collections.MutableList<out kotlin.Any?>?..kotlin.collections.List<kotlin.Any?>?)>")!>result_8<!>
+}
diff --git a/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.ni.fir.kt b/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.ni.fir.kt
new file mode 100644
index 00000000000..bbfcd1839ba
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.ni.fir.kt
@@ -0,0 +1,273 @@
+// !DIAGNOSTICS: -UNSUPPORTED -UNUSED_EXPRESSION -DEBUG_INFO_SMARTCAST -USELESS_CAST -UNUSED_PARAMETER -UNCHECKED_CAST -CAST_NEVER_SUCCEEDS -UNUSED_VARIABLE -UNREACHABLE_CODE -DEBUG_INFO_CONSTANT
+// !LANGUAGE: +NewInference
+// SKIP_TXT
+
+// FILE: Test.java
+import java.util.List;
+
+public class Test {
+    public static B foo() { return null; }
+    public static <T> T bar() { return null; }
+    public static <T> T id(T x) { return null; }
+    public static <T> List<T> getList(T x) { return null; }
+    public static List getRawList() { return null; }
+}
+
+// FILE: main.kt
+class A<T>(x: T)
+class B
+
+fun <T> select(vararg x: T): T = null as T
+
+fun case_1() {
+    val x = Test.foo() // B!
+
+    val result_1 = select(A(x), A(B()))
+    val result_2 = select(A(B()), A(x), A(if (true) B() else null))
+    val result_3 = select(A(x), A(if (true) B() else null))
+
+    result_1
+    result_2
+    result_3
+}
+
+fun case_2() {
+    val x = Test.bar<Any>() // Any!
+    val y: Any? = null
+
+    val result = select(A(Any()), A(y), A(x))
+
+    result
+}
+
+fun <T> case_3() {
+    val x = Test.bar<T>() // T!
+    val y: T? = null
+    val result = select(A(y), A(x), A(null as T))
+
+    result
+}
+
+fun case_4() {
+    val x = Test.bar<Nothing>() // Nothing!
+    val y = null // Nothing?
+
+    val result = select(A(x), A(y), A(return))
+
+    result
+}
+
+class C<T, K, L>(x: T, y: K, z: L)
+
+fun case_5() {
+    val x = Test.foo() // B!
+    val y: B? = null
+
+    val result_1 = select(C(x, B(), 10), C(B(), x, 10))
+    val result_2 = select(C(B(), x, y), C(x, B(), y), C(y, x, B()), C(x, y, B()), C(y, B(), x), C(B(), y, x))
+
+    result_1
+    result_2
+}
+
+fun case_6() {
+    val x1 = Test.bar<C<C<A<Float>, B, Int>, B, B>>() // C<C<A<Float>, B, Int>, B, B>!
+    val x2 = C(null as C<A<Float?>, B?, Int>?, Test.id(B()), B()) // C<C<A<Float?>, B?, Int>?, B?, B>
+    val x3 = C(C(A(Test.id(1f)), B(), Test.id(1)), Test.id(B()), B()) // C<C<A<Float!>, B, Int!>, B!, B>
+    val x4 = C(C(A(Test.id(3f)), null as B?, null as Int?), null as B?, null as B?) // C<C<A<Float?>?, B?, Int?>, B?, B?>
+    val x5 = C(Test.id(C(A(1f), Test.id(B()), 1)), B(), Test.id(B())) // C<C<A<Float>, B!, Int>!, B, B!>
+    val x6 = Test.id(C(select(C(Test.id(A(1f)), null as B?, null as Int?), null), Test.id(B()), null as B?)) // C<C<A<Float!>, B?, Int?>?, B!, B?>!
+    val x7 = C(C(Test.id(A(1f)), B(), 1), B(), B()) // C<C<A<Float>!, B, Int>, B, B>
+    val x8 = C(Test.id(C(null as A<Float?>?, B(), null as Int?)), null as B?, Test.id(B())) // C<C<A<Float?>?, B, Int?>, B?, B>
+    val x9 = null as C<C<A<Float>, B?, Int>, B, B>? // C<C<A<Float>, B?, Int>, B, B>?
+
+    val result_1 = select(x1, x2, x3, x4, x5, x6, x7, x8, x9)
+    val result_2 = select(x9, x8, x7, x6, x5, x4, x3, x2, x1)
+    val result_3 = select(x5, x7, x9, x3, x1, x2, x8, x4, x6)
+
+    result_1
+    result_2
+    result_3
+}
+
+fun case_7() {
+    val x0: Int = 1
+    val x1 = C(A(Test.id(x0)), B(), B())
+    val x2 = C(Test.id(A(1)), B(), B())
+    x1
+    x2
+
+    val result_5 = select(x1, x2)
+    result_5
+}
+
+fun case_8() {
+    val x1 = A(10)
+    val x2 = select(A(""), null)
+    val x3 = Test.id(A(null))
+
+    val result_1 = select(x1, x2, x3)
+    result_1
+}
+
+fun case_9() {
+    val x1 = A(A(10))
+    val x2 = A(select(A(""), null))
+    val x3 = A(Test.id(A('s')))
+
+    val result_1 = select(x1, x2, x3)
+    result_1
+}
+
+fun case_10() {
+    val x1 = 10
+    val x2 = select(10, null)
+    val x3 = Test.id(10)
+
+    val result_1 = select(x2, x1, x3)
+    val result_2 = select(x2, x3, x1)
+    val result_3 = select(x1, x2, x3)
+    val result_4 = select(x1, x3, x2)
+    val result_5 = select(x3, x2, x1)
+    val result_6 = select(x3, x1, x2)
+
+    result_1
+    result_2
+    result_3
+    result_4
+    result_5
+    result_6
+}
+
+fun <T> case_11(y: T) {
+    val x1 = Test.bar<T>() // T!
+    val x2 = select(y, null)
+    if (y != null) {
+        val x3 = Test.id(y) // T!
+        val result_1 = select(A(y), A(x1))
+        val result_2 = select(A(y), A(x1), A(x2))
+        val result_3 = select(A(y), A(x3), A(x2))
+        val result_4 = select(A(y as T), A(x1))
+        val result_5 = select(A(y as T), A(x1), A(x2))
+        val result_6 = select(A(y as T), A(x3), A(x2))
+        val result_7 = select(A(y as T), A(x1))
+        val result_8 = select(A(y as T), A(x3))
+        val result_9 = select(A(x3), A(y as T))
+
+        val result_10 = select(y, x1)
+        val result_11 = select(y, x2, x2)
+        val result_12 = select(y, x3, x2)
+        val result_13 = select(y as T, x1)
+        val result_14 = select(y as T, x1, x2)
+        val result_15 = select(y as T, x3, x2)
+        val result_16 = select(y as T, x1)
+        val result_17 = select(y as T, x3)
+        val result_18 = select(x3, y as T)
+
+        x1
+        x2
+        x3
+        y
+
+        result_1
+        result_2
+        result_3
+        result_4
+        result_5
+        result_6
+        result_7
+        result_8
+        result_9
+
+        result_10
+        result_11
+        result_12
+        result_13
+        result_14
+        result_15
+        result_16
+        result_17
+        result_18
+    }
+}
+
+fun case_12() {
+    val x1 = Test.getList(10)
+    val x2 = null as MutableList<Int>
+    val x3 = select(null as List<Int>, null)
+
+    val result_1 = select(x1, x2)
+    val result_2 = select(x2, x1)
+    val result_3 = select(x2, x1, x3)
+    val result_4 = select(x3, x1)
+    val result_5 = select(A(x1), A(x2))
+    val result_6 = select(A(x2), A(x1))
+    val result_7 = select(A(x3), A(x1), A(x2))
+    val result_8 = select(A(x1), A(x3))
+
+    result_1
+    result_2
+    result_3
+    result_4
+    result_5
+    result_6
+    result_7
+    result_8
+}
+
+fun case_13() {
+    val x1 = Test.getList(10)
+    val x2: dynamic = null
+    val x3 = null as MutableList<Int>
+    val x4 = select(null as List<Int>, null)
+
+    val result_1 = <!INAPPLICABLE_CANDIDATE!>select<!>(x1, x2, x3, x4)
+    val result_2 = <!INAPPLICABLE_CANDIDATE!>select<!>(x2, x1)
+    val result_3 = <!INAPPLICABLE_CANDIDATE!>select<!>(x2, x1, x3)
+    val result_4 = <!INAPPLICABLE_CANDIDATE!>select<!>(x3, x2)
+    val result_5 = <!INAPPLICABLE_CANDIDATE!>select<!>(x4, x2)
+    val result_6 = <!INAPPLICABLE_CANDIDATE!>select<!>(x4, x3, x2)
+    val result_7 = <!INAPPLICABLE_CANDIDATE!>select<!>(A(x1), <!INAPPLICABLE_CANDIDATE!>A<!>(x2), A(x3), A(x4))
+    val result_8 = <!INAPPLICABLE_CANDIDATE!>select<!>(<!INAPPLICABLE_CANDIDATE!>A<!>(x2), A(x1))
+    val result_9 = <!INAPPLICABLE_CANDIDATE!>select<!>(<!INAPPLICABLE_CANDIDATE!>A<!>(x2), A(x1), A(x3))
+    val result_10 = <!INAPPLICABLE_CANDIDATE!>select<!>(A(x3), <!INAPPLICABLE_CANDIDATE!>A<!>(x2))
+    val result_11 = <!INAPPLICABLE_CANDIDATE!>select<!>(A(x4), <!INAPPLICABLE_CANDIDATE!>A<!>(x2))
+    val result_12 = <!INAPPLICABLE_CANDIDATE!>select<!>(A(x4), A(x3), <!INAPPLICABLE_CANDIDATE!>A<!>(x2))
+
+    result_1
+    result_2
+    result_3
+    result_4
+    result_5
+    result_6
+    result_7
+    result_8
+    result_9
+    result_10
+    result_11
+    result_12
+}
+
+fun case_14() {
+    val x1 = Test.getRawList()
+    val x2 = null as List<Int>
+    val x3 = select(null as MutableList<Int>, null)
+
+    val result_1 = select(x1, x2)
+    val result_2 = select(x2, x1)
+    val result_3 = select(x2, x1, x3)
+    val result_4 = select(x3, x1)
+    val result_5 = select(A(x1), A(x2))
+    val result_6 = select(A(x2), A(x1))
+    val result_7 = select(A(x3), A(x1), A(x2))
+    val result_8 = select(A(x1), A(x3))
+
+    result_1
+    result_2
+    result_3
+    result_4
+    result_5
+    result_6
+    result_7
+    result_8
+}
diff --git a/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.ni.kt b/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.ni.kt
new file mode 100644
index 00000000000..2ea53605e6f
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.ni.kt
@@ -0,0 +1,273 @@
+// !DIAGNOSTICS: -UNSUPPORTED -UNUSED_EXPRESSION -DEBUG_INFO_SMARTCAST -USELESS_CAST -UNUSED_PARAMETER -UNCHECKED_CAST -CAST_NEVER_SUCCEEDS -UNUSED_VARIABLE -UNREACHABLE_CODE -DEBUG_INFO_CONSTANT
+// !LANGUAGE: +NewInference
+// SKIP_TXT
+
+// FILE: Test.java
+import java.util.List;
+
+public class Test {
+    public static B foo() { return null; }
+    public static <T> T bar() { return null; }
+    public static <T> T id(T x) { return null; }
+    public static <T> List<T> getList(T x) { return null; }
+    public static List getRawList() { return null; }
+}
+
+// FILE: main.kt
+class A<T>(x: T)
+class B
+
+fun <T> select(vararg x: T): T = null as T
+
+fun case_1() {
+    val x = Test.foo() // B!
+
+    val result_1 = select(A(x), A(B()))
+    val result_2 = select(A(B()), A(x), A(if (true) B() else null))
+    val result_3 = select(A(x), A(if (true) B() else null))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(B..B?)>")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(B..B?)>")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(B..B?)>")!>result_3<!>
+}
+
+fun case_2() {
+    val x = Test.bar<Any>() // Any!
+    val y: Any? = null
+
+    val result = select(A(Any()), A(y), A(x))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.Any..kotlin.Any?)>")!>result<!>
+}
+
+fun <T> case_3() {
+    val x = Test.bar<T>() // T!
+    val y: T? = null
+    val result = select(A(y), A(x), A(null as T))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(T..T?)>")!>result<!>
+}
+
+fun case_4() {
+    val x = Test.bar<Nothing>() // Nothing!
+    val y = null // Nothing?
+
+    val result = select(A(x), A(y), A(return))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.Nothing..kotlin.Nothing?)>")!>result<!>
+}
+
+class C<T, K, L>(x: T, y: K, z: L)
+
+fun case_5() {
+    val x = Test.foo() // B!
+    val y: B? = null
+
+    val result_1 = select(C(x, B(), 10), C(B(), x, 10))
+    val result_2 = select(C(B(), x, y), C(x, B(), y), C(y, x, B()), C(x, y, B()), C(y, B(), x), C(B(), y, x))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<(B..B?), B, kotlin.Int>")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<(B..B?), (B..B?), (B..B?)>")!>result_2<!>
+}
+
+fun case_6() {
+    val x1 = Test.bar<C<C<A<Float>, B, Int>, B, B>>() // C<C<A<Float>, B, Int>, B, B>!
+    val x2 = C(null as C<A<Float?>, B?, Int>?, Test.id(B()), B()) // C<C<A<Float?>, B?, Int>?, B?, B>
+    val x3 = C(C(A(Test.id(1f)), B(), Test.id(1)), Test.id(B()), B()) // C<C<A<Float!>, B, Int!>, B!, B>
+    val x4 = C(C(A(Test.id(3f)), null as B?, null as Int?), null as B?, null as B?) // C<C<A<Float?>?, B?, Int?>, B?, B?>
+    val x5 = C(Test.id(C(A(1f), Test.id(B()), 1)), B(), Test.id(B())) // C<C<A<Float>, B!, Int>!, B, B!>
+    val x6 = Test.id(C(select(C(Test.id(A(1f)), null as B?, null as Int?), null), Test.id(B()), null as B?)) // C<C<A<Float!>, B?, Int?>?, B!, B?>!
+    val x7 = C(C(Test.id(A(1f)), B(), 1), B(), B()) // C<C<A<Float>!, B, Int>, B, B>
+    val x8 = C(Test.id(C(null as A<Float?>?, B(), null as Int?)), null as B?, Test.id(B())) // C<C<A<Float?>?, B, Int?>, B?, B>
+    val x9 = null as C<C<A<Float>, B?, Int>, B, B>? // C<C<A<Float>, B?, Int>, B, B>?
+
+    val result_1 = select(x1, x2, x3, x4, x5, x6, x7, x8, x9)
+    val result_2 = select(x9, x8, x7, x6, x5, x4, x3, x2, x1)
+    val result_3 = select(x5, x7, x9, x3, x1, x2, x8, x4, x6)
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<out C<out A<(kotlin.Float..kotlin.Float?)>?, (B..B?), (kotlin.Int..kotlin.Int?)>?, (B..B?), (B..B?)>?")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<out C<out A<(kotlin.Float..kotlin.Float?)>?, (B..B?), (kotlin.Int..kotlin.Int?)>?, (B..B?), (B..B?)>?")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<out C<out A<(kotlin.Float..kotlin.Float?)>?, (B..B?), (kotlin.Int..kotlin.Int?)>?, (B..B?), (B..B?)>?")!>result_3<!>
+}
+
+fun case_7() {
+    val x0: Int = 1
+    val x1 = C(A(Test.id(x0)), B(), B())
+    val x2 = C(Test.id(A(1)), B(), B())
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<A<(kotlin.Int..kotlin.Int?)>, B, B>")!>x1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<(A<kotlin.Int>..A<kotlin.Int>?), B, B>")!>x2<!>
+
+    val result_5 = select(x1, x2)
+    <!DEBUG_INFO_EXPRESSION_TYPE("C<A<(kotlin.Int..kotlin.Int?)>, B, B>")!>result_5<!>
+}
+
+fun case_8() {
+    val x1 = A(10)
+    val x2 = select(A(""), null)
+    val x3 = Test.id(A(null))
+
+    val result_1 = select(x1, x2, x3)
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out {Comparable<{Int & String}> & java.io.Serializable}?>?")!>result_1<!>
+}
+
+fun case_9() {
+    val x1 = A(A(10))
+    val x2 = A(select(A(""), null))
+    val x3 = A(Test.id(A('s')))
+
+    val result_1 = select(x1, x2, x3)
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out A<out {Comparable<{Char & Int & String}> & java.io.Serializable}>?>")!>result_1<!>
+}
+
+fun case_10() {
+    val x1 = 10
+    val x2 = select(10, null)
+    val x3 = Test.id(10)
+
+    val result_1 = select(x2, x1, x3)
+    val result_2 = select(x2, x3, x1)
+    val result_3 = select(x1, x2, x3)
+    val result_4 = select(x1, x3, x2)
+    val result_5 = select(x3, x2, x1)
+    val result_6 = select(x3, x1, x2)
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_3<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_4<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_5<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>result_6<!>
+}
+
+fun <T> case_11(y: T) {
+    val x1 = Test.bar<T>() // T!
+    val x2 = select(y, null)
+    if (y != null) {
+        val x3 = Test.id(y) // T!
+        val result_1 = select(A(y), A(x1))
+        val result_2 = select(A(y), A(x1), A(x2))
+        val result_3 = select(A(y), A(x3), A(x2))
+        val result_4 = select(A(y as T), A(x1))
+        val result_5 = select(A(y as T), A(x1), A(x2))
+        val result_6 = select(A(y as T), A(x3), A(x2))
+        val result_7 = select(A(y as T), A(x1))
+        val result_8 = select(A(y as T), A(x3))
+        val result_9 = select(A(x3), A(y as T))
+
+        val result_10 = select(y, x1)
+        val result_11 = select(y, x2, x2)
+        val result_12 = select(y, x3, x2)
+        val result_13 = select(y as T, x1)
+        val result_14 = select(y as T, x1, x2)
+        val result_15 = select(y as T, x3, x2)
+        val result_16 = select(y as T, x1)
+        val result_17 = select(y as T, x3)
+        val result_18 = select(x3, y as T)
+
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>x1<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>x2<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T!!..T?)")!>x3<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T & T!!")!>y<!>
+
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<out (T..T?)>")!>result_1<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<out T?>")!>result_2<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<(T!!..T?)>")!>result_3<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<T>")!>result_4<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<(T..T?)>")!>result_5<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<(T!!..T?)>")!>result_6<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<T>")!>result_7<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<T>")!>result_8<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("A<(T!!..T?)>")!>result_9<!>
+
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>result_10<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>result_11<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>result_12<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>result_13<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>result_14<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("T?")!>result_15<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>result_16<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>result_17<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("(T..T?)")!>result_18<!>
+    }
+}
+
+fun case_12() {
+    val x1 = Test.getList(10)
+    val x2 = null as MutableList<Int>
+    val x3 = select(null as List<Int>, null)
+
+    val result_1 = select(x1, x2)
+    val result_2 = select(x2, x1)
+    val result_3 = select(x2, x1, x3)
+    val result_4 = select(x3, x1)
+    val result_5 = select(A(x1), A(x2))
+    val result_6 = select(A(x2), A(x1))
+    val result_7 = select(A(x3), A(x1), A(x2))
+    val result_8 = select(A(x1), A(x3))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.MutableList<(kotlin.Int..kotlin.Int?)>..kotlin.collections.List<(kotlin.Int..kotlin.Int?)>?)")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.MutableList<kotlin.Int>..kotlin.collections.List<kotlin.Int>?)")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.List<(kotlin.Int..kotlin.Int?)>?")!>result_3<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.List<kotlin.Int>?")!>result_4<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.collections.MutableList<(kotlin.Int..kotlin.Int?)>..kotlin.collections.List<(kotlin.Int..kotlin.Int?)>?)>")!>result_5<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<kotlin.collections.MutableList<kotlin.Int>>")!>result_6<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.collections.MutableList<(kotlin.Int..kotlin.Int?)>..kotlin.collections.List<(kotlin.Int..kotlin.Int?)>?)>")!>result_7<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<(kotlin.collections.MutableList<(kotlin.Int..kotlin.Int?)>..kotlin.collections.List<(kotlin.Int..kotlin.Int?)>?)>")!>result_8<!>
+}
+
+fun case_13() {
+    val x1 = Test.getList(10)
+    val x2: dynamic = null
+    val x3 = null as MutableList<Int>
+    val x4 = select(null as List<Int>, null)
+
+    val result_1 = select(x1, x2, x3, x4)
+    val result_2 = select(x2, x1)
+    val result_3 = select(x2, x1, x3)
+    val result_4 = select(x3, x2)
+    val result_5 = select(x4, x2)
+    val result_6 = select(x4, x3, x2)
+    val result_7 = select(A(x1), A(x2), A(x3), A(x4))
+    val result_8 = select(A(x2), A(x1))
+    val result_9 = select(A(x2), A(x1), A(x3))
+    val result_10 = select(A(x3), A(x2))
+    val result_11 = select(A(x4), A(x2))
+    val result_12 = select(A(x4), A(x3), A(x2))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_3<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_4<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_5<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("dynamic")!>result_6<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<dynamic>")!>result_7<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<dynamic>")!>result_8<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<dynamic>")!>result_9<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<dynamic>")!>result_10<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<dynamic>")!>result_11<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<dynamic>")!>result_12<!>
+}
+
+fun case_14() {
+    val x1 = Test.getRawList()
+    val x2 = null as List<Int>
+    val x3 = select(null as MutableList<Int>, null)
+
+    val result_1 = select(x1, x2)
+    val result_2 = select(x2, x1)
+    val result_3 = select(x2, x1, x3)
+    val result_4 = select(x3, x1)
+    val result_5 = select(A(x1), A(x2))
+    val result_6 = select(A(x2), A(x1))
+    val result_7 = select(A(x3), A(x1), A(x2))
+    val result_8 = select(A(x1), A(x3))
+
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.List<kotlin.Any?>..kotlin.collections.List<*>?)")!>result_1<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.List<kotlin.Any?>..kotlin.collections.List<*>?)")!>result_2<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.List<kotlin.Any?>?..kotlin.collections.List<*>?)")!>result_3<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("(kotlin.collections.MutableList<out kotlin.Any?>?..kotlin.collections.List<*>?)")!>result_4<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out (kotlin.collections.List<kotlin.Any?>..kotlin.collections.List<*>?)>")!>result_5<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out (kotlin.collections.List<kotlin.Any?>..kotlin.collections.List<*>?)>")!>result_6<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out (kotlin.collections.List<kotlin.Any?>?..kotlin.collections.List<*>?)>")!>result_7<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("A<out (kotlin.collections.MutableList<out kotlin.Any?>?..kotlin.collections.List<*>?)>")!>result_8<!>
+}
diff --git a/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java
index 35524c58668..ae713e90ed8 100644
--- a/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java
@@ -11203,6 +11203,16 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                     runTest("compiler/testData/diagnostics/tests/inference/upperBounds/doNotInferFromBoundsOnly.kt");
                 }
 
+                @TestMetadata("flexibilityInCommonSuperTypeCalculation.kt")
+                public void testFlexibilityInCommonSuperTypeCalculation() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.kt");
+                }
+
+                @TestMetadata("flexibilityInCommonSuperTypeCalculation.ni.kt")
+                public void testFlexibilityInCommonSuperTypeCalculation_ni() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.ni.kt");
+                }
+
                 @TestMetadata("intersectUpperBounds.kt")
                 public void testIntersectUpperBounds() throws Exception {
                     runTest("compiler/testData/diagnostics/tests/inference/upperBounds/intersectUpperBounds.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java
index 053d687294a..1d401b64cec 100644
--- a/compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java
@@ -11198,6 +11198,16 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                     runTest("compiler/testData/diagnostics/tests/inference/upperBounds/doNotInferFromBoundsOnly.kt");
                 }
 
+                @TestMetadata("flexibilityInCommonSuperTypeCalculation.kt")
+                public void testFlexibilityInCommonSuperTypeCalculation() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.kt");
+                }
+
+                @TestMetadata("flexibilityInCommonSuperTypeCalculation.ni.kt")
+                public void testFlexibilityInCommonSuperTypeCalculation_ni() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/inference/upperBounds/flexibilityInCommonSuperTypeCalculation.ni.kt");
+                }
+
                 @TestMetadata("intersectUpperBounds.kt")
                 public void testIntersectUpperBounds() throws Exception {
                     runTest("compiler/testData/diagnostics/tests/inference/upperBounds/intersectUpperBounds.kt");
diff --git a/core/type-system/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt b/core/type-system/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt
index cc7f3739be2..e86a22940a9 100644
--- a/core/type-system/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt
+++ b/core/type-system/src/org/jetbrains/kotlin/types/AbstractTypeChecker.kt
@@ -580,3 +580,28 @@ object AbstractNullabilityChecker {
         return isEqualTypeConstructors(type.typeConstructor(), end)
     }
 }
+
+
+object AbstractFlexibilityChecker {
+    fun TypeSystemCommonSuperTypesContext.hasDifferentFlexibilityAtDepth(types: Collection<KotlinTypeMarker>): Boolean {
+        if (types.isEmpty()) return false
+        if (hasDifferentFlexibility(types)) return true
+
+        for (i in 0 until types.first().argumentsCount()) {
+            val typeArgumentForOtherTypes = types.mapNotNull {
+                if (it.argumentsCount() > i && !it.getArgument(i).isStarProjection()) it.getArgument(i).getType() else null
+            }
+
+            if (hasDifferentFlexibilityAtDepth(typeArgumentForOtherTypes)) return true
+        }
+
+        return false
+    }
+
+    private fun TypeSystemCommonSuperTypesContext.hasDifferentFlexibility(types: Collection<KotlinTypeMarker>): Boolean {
+        val firstType = types.first()
+        if (types.all { it === firstType }) return false
+
+        return !types.all { it.isFlexible() } && !types.all { !it.isFlexible() }
+    }
+}