diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/LogicSystem.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/LogicSystem.kt
index dfdc0d3fe79..6e11d2ed8cf 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/LogicSystem.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/dfa/LogicSystem.kt
@@ -140,14 +140,17 @@ abstract class LogicSystem<FLOW : Flow>(protected val context: ConeInferenceCont
 
     private fun orForTypes(types: Collection<Set<ConeKotlinType>>): MutableSet<ConeKotlinType> {
         if (types.any { it.isEmpty() }) return mutableSetOf()
-        val allTypes = types.flatMapTo(mutableSetOf()) { it }
-        val commonTypes = allTypes.toMutableSet()
-        types.forEach { commonTypes.retainAll(it) }
-        val differentTypes = types.mapNotNull { typeSet -> (typeSet - commonTypes).takeIf { it.isNotEmpty() } }
-        if (differentTypes.size == types.size) {
-            context.commonSuperTypeOrNull(differentTypes.flatten())?.let { commonTypes += it }
+        val intersectedTypes = types.map {
+            if (it.size > 1) {
+                context.intersectTypes(it.toList()) as ConeKotlinType
+            } else {
+                assert(it.size == 1) { "We've already checked each set of types is not empty." }
+                it.single()
+            }
         }
-        return commonTypes
+        val result = mutableSetOf<ConeKotlinType>()
+        context.commonSuperTypeOrNull(intersectedTypes)?.let { result.add(it) }
+        return result
     }
 
     protected fun and(statements: Collection<TypeStatement>): MutableTypeStatement =
diff --git a/compiler/testData/ir/irText/firProblems/inapplicableCollectionSet.fir.kt.txt b/compiler/testData/ir/irText/firProblems/inapplicableCollectionSet.fir.kt.txt
index 50b799c254c..7537cea0936 100644
--- a/compiler/testData/ir/irText/firProblems/inapplicableCollectionSet.fir.kt.txt
+++ b/compiler/testData/ir/irText/firProblems/inapplicableCollectionSet.fir.kt.txt
@@ -23,10 +23,10 @@ class Flaf {
             result = Flaf(javaName = javaName)
           }
         }
-        error("") /* ErrorCallExpression */javaName; result;
+        <this>.<get-INSTANCES>().set<String, Flaf>(key = javaName, value = result /*as Flaf */)
       }
     }
-    return result
+    return result /*as Flaf */
   }
 
 }
diff --git a/compiler/testData/ir/irText/firProblems/inapplicableCollectionSet.fir.txt b/compiler/testData/ir/irText/firProblems/inapplicableCollectionSet.fir.txt
index 4a37c0bf4a6..43ce9eeb68b 100644
--- a/compiler/testData/ir/irText/firProblems/inapplicableCollectionSet.fir.txt
+++ b/compiler/testData/ir/irText/firProblems/inapplicableCollectionSet.fir.txt
@@ -62,11 +62,17 @@ FILE fqName:<root> fileName:/inapplicableCollectionSet.kt
                     SET_VAR 'var result: <root>.Flaf? [var] declared in <root>.Flaf.forJavaName' type=kotlin.Unit origin=EQ
                       CONSTRUCTOR_CALL 'public constructor <init> (javaName: kotlin.String) [primary] declared in <root>.Flaf' type=<root>.Flaf origin=null
                         javaName: GET_VAR 'javaName: kotlin.String declared in <root>.Flaf.forJavaName' type=kotlin.String origin=null
-              ERROR_CALL 'Unresolved reference: <Inapplicable(INAPPLICABLE): kotlin/collections/set>#' type=kotlin.Unit
-                GET_VAR 'javaName: kotlin.String declared in <root>.Flaf.forJavaName' type=kotlin.String origin=null
-                GET_VAR 'var result: <root>.Flaf? [var] declared in <root>.Flaf.forJavaName' type=<root>.Flaf? origin=null
+              CALL 'public final fun set <K, V> (key: K of kotlin.collections.set, value: V of kotlin.collections.set): kotlin.Unit [inline,operator] declared in kotlin.collections' type=kotlin.Unit origin=null
+                <K>: kotlin.String
+                <V>: <root>.Flaf
+                $receiver: CALL 'private final fun <get-INSTANCES> (): kotlin.collections.MutableMap<kotlin.String, <root>.Flaf> declared in <root>.Flaf' type=kotlin.collections.MutableMap<kotlin.String, <root>.Flaf> origin=GET_PROPERTY
+                  $this: GET_VAR '<this>: <root>.Flaf declared in <root>.Flaf.forJavaName' type=<root>.Flaf origin=null
+                key: GET_VAR 'javaName: kotlin.String declared in <root>.Flaf.forJavaName' type=kotlin.String origin=null
+                value: TYPE_OP type=<root>.Flaf origin=IMPLICIT_CAST typeOperand=<root>.Flaf
+                  GET_VAR 'var result: <root>.Flaf? [var] declared in <root>.Flaf.forJavaName' type=<root>.Flaf? origin=null
         RETURN type=kotlin.Nothing from='public final fun forJavaName (javaName: kotlin.String): <root>.Flaf declared in <root>.Flaf'
-          GET_VAR 'var result: <root>.Flaf? [var] declared in <root>.Flaf.forJavaName' type=<root>.Flaf? origin=null
+          TYPE_OP type=<root>.Flaf origin=IMPLICIT_CAST typeOperand=<root>.Flaf
+            GET_VAR 'var result: <root>.Flaf? [var] declared in <root>.Flaf.forJavaName' type=<root>.Flaf? origin=null
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/42.fir.kt b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/42.fir.kt
index 3f3d9c5291d..9f0ec94f07c 100644
--- a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/42.fir.kt
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/42.fir.kt
@@ -19,8 +19,8 @@ fun case_1(x: Any) {
  */
 fun case_2(x: Any?) {
     if (x is Int || x is Float?) {
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any?")!>x<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any?")!>x<!>.<!UNRESOLVED_REFERENCE!>toByte<!>()
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Int & kotlin.Float>? & kotlin.Any?")!>x<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Int & kotlin.Float>? & kotlin.Any?")!>x<!>.<!INAPPLICABLE_CANDIDATE!>toByte<!>()
     }
 }
 
@@ -30,8 +30,8 @@ fun case_2(x: Any?) {
  */
 fun case_3(x: Any?) {
     if (x is Int? || x is Float) {
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any?")!>x<!>
-        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Any?")!>x<!>.<!UNRESOLVED_REFERENCE!>toByte<!>()
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Int & kotlin.Float>? & kotlin.Any?")!>x<!>
+        <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number? & kotlin.Comparable<kotlin.Int & kotlin.Float>? & kotlin.Any?")!>x<!>.<!INAPPLICABLE_CANDIDATE!>toByte<!>()
     }
 }