diff --git a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
index dad5ff47f5a..7083799bf8e 100644
--- a/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
+++ b/analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
@@ -33394,6 +33394,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 runTest("compiler/testData/diagnostics/tests/typeParameters/kt46186.kt");
             }
 
+            @Test
+            @TestMetadata("kt46186withEmptyIntersections.kt")
+            public void testKt46186withEmptyIntersections() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.kt");
+            }
+
             @Test
             @TestMetadata("misplacedConstraints.kt")
             public void testMisplacedConstraints() throws Exception {
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
index 18e82c7dac9..9c8e33d515a 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirLightTreeOldFrontendDiagnosticsTestGenerated.java
@@ -33394,6 +33394,12 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
                 runTest("compiler/testData/diagnostics/tests/typeParameters/kt46186.kt");
             }
 
+            @Test
+            @TestMetadata("kt46186withEmptyIntersections.kt")
+            public void testKt46186withEmptyIntersections() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.kt");
+            }
+
             @Test
             @TestMetadata("misplacedConstraints.kt")
             public void testMisplacedConstraints() throws Exception {
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
index f57a9f64f26..5ca95d6b070 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirPsiOldFrontendDiagnosticsTestGenerated.java
@@ -33490,6 +33490,12 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
                 runTest("compiler/testData/diagnostics/tests/typeParameters/kt46186.kt");
             }
 
+            @Test
+            @TestMetadata("kt46186withEmptyIntersections.kt")
+            public void testKt46186withEmptyIntersections() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.kt");
+            }
+
             @Test
             @TestMetadata("misplacedConstraints.kt")
             public void testMisplacedConstraints() throws Exception {
diff --git a/compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/inference/components/ResultTypeResolver.kt b/compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/inference/components/ResultTypeResolver.kt
index 5e5395e6219..48a216ea54e 100644
--- a/compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/inference/components/ResultTypeResolver.kt
+++ b/compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/inference/components/ResultTypeResolver.kt
@@ -265,8 +265,9 @@ class ResultTypeResolver(
     }
 
     private fun Context.computeUpperType(upperConstraints: List<Constraint>): KotlinTypeMarker {
-        // TODO: Remove this after stopping support of K1
-        return if (!isK2) {
+        return if (languageVersionSettings.supportsFeature(LanguageFeature.AllowEmptyIntersectionsInResultTypeResolver)) {
+            intersectTypes(upperConstraints.map { it.type })
+        } else {
             val intersectionUpperType = intersectTypes(upperConstraints.map { it.type })
             val resultIsActuallyIntersection = intersectionUpperType.typeConstructor().isIntersection()
 
@@ -291,8 +292,6 @@ class ResultTypeResolver(
                 if (filteredUpperConstraints.isNotEmpty()) intersectTypes(filteredUpperConstraints) else intersectionUpperType
             } else intersectionUpperType
             upperType
-        } else {
-            intersectTypes(upperConstraints.map { it.type })
         }
     }
 
diff --git a/compiler/testData/diagnostics/tests/typeParameters/kt46186.fir.kt b/compiler/testData/diagnostics/tests/typeParameters/kt46186.fir.kt
index b6ab6e72dc9..20a9e1bba95 100644
--- a/compiler/testData/diagnostics/tests/typeParameters/kt46186.fir.kt
+++ b/compiler/testData/diagnostics/tests/typeParameters/kt46186.fir.kt
@@ -1,4 +1,5 @@
 // !DIAGNOSTICS: -FINAL_UPPER_BOUND -CAST_NEVER_SUCCEEDS
+// !LANGUAGE: -AllowEmptyIntersectionsInResultTypeResolver
 
 interface I
 
@@ -9,13 +10,13 @@ abstract class View4
 interface View5
 
 fun <T: View1> findViewById1(): T = null as T
-fun test1(): I = findViewById1()
+fun test1(): I = <!NEW_INFERENCE_ERROR, RETURN_TYPE_MISMATCH!>findViewById1()<!>
 
 fun <T: View2> findViewById2(): T = null as T
 fun test2(): I = findViewById2()
 
 inline fun <reified T: View1> findViewById3(): T = null as T
-fun test3(): I = findViewById3()
+fun test3(): I = <!NEW_INFERENCE_ERROR, RETURN_TYPE_MISMATCH!>findViewById3()<!>
 
 inline fun <reified T: View2> findViewById4(): T = null as T
 fun test4(): I = findViewById4()
@@ -39,17 +40,17 @@ inline fun <reified T> findViewById10(): T where T: View3, T: View5 = null as T
 fun test10(): I = findViewById10()
 
 fun <T: View2> findViewById11(): T = null as T
-fun test11(): View4 = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>findViewById11<!>()
+fun test11(): View4 = <!NEW_INFERENCE_ERROR, RETURN_TYPE_MISMATCH!>findViewById11()<!>
 
 object Obj {
     fun <T: I> findViewById1(): T = null as T
-    fun test1(): View1 = findViewById1()
+    fun test1(): View1 = <!NEW_INFERENCE_ERROR, RETURN_TYPE_MISMATCH!>findViewById1()<!>
 
     fun <T: I> findViewById2(): T = null as T
     fun test2(): View2 = findViewById2()
 
     inline fun <reified T: I> findViewById3(): T = null as T
-    fun test3(): View1 = findViewById3()
+    fun test3(): View1 = <!NEW_INFERENCE_ERROR, RETURN_TYPE_MISMATCH!>findViewById3()<!>
 
     inline fun <reified T: I> findViewById4(): T = null as T
     fun test4(): View2 = findViewById4()
@@ -67,13 +68,13 @@ object Obj {
     fun test8(): View4 = findViewById8()
 
     fun <T> findViewById9(): T where T: View3, T: View5 = null as T
-    fun test9(): View1 = findViewById9()
+    fun test9(): View1 = <!NEW_INFERENCE_ERROR, RETURN_TYPE_MISMATCH!>findViewById9()<!>
 
     inline fun <reified T> findViewById10(): T where T: View3, T: View5 = null as T
-    fun test10(): View1 = findViewById10()
+    fun test10(): View1 = <!NEW_INFERENCE_ERROR, RETURN_TYPE_MISMATCH!>findViewById10()<!>
 
     fun <T: View2> findViewById11(): T = null as T
-    fun test11(): View4 = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>findViewById11<!>()
+    fun test11(): View4 = <!NEW_INFERENCE_ERROR, RETURN_TYPE_MISMATCH!>findViewById11()<!>
 }
 
 interface A
diff --git a/compiler/testData/diagnostics/tests/typeParameters/kt46186.kt b/compiler/testData/diagnostics/tests/typeParameters/kt46186.kt
index 1f651e5677b..09b059945f9 100644
--- a/compiler/testData/diagnostics/tests/typeParameters/kt46186.kt
+++ b/compiler/testData/diagnostics/tests/typeParameters/kt46186.kt
@@ -1,4 +1,5 @@
 // !DIAGNOSTICS: -FINAL_UPPER_BOUND -CAST_NEVER_SUCCEEDS
+// !LANGUAGE: -AllowEmptyIntersectionsInResultTypeResolver
 
 interface I
 
diff --git a/compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.fir.kt b/compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.fir.kt
new file mode 100644
index 00000000000..d2268e78b1c
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.fir.kt
@@ -0,0 +1,84 @@
+// !DIAGNOSTICS: -FINAL_UPPER_BOUND -CAST_NEVER_SUCCEEDS
+// !LANGUAGE: +AllowEmptyIntersectionsInResultTypeResolver
+
+interface I
+
+class View1
+open class View2
+interface View3
+abstract class View4
+interface View5
+
+fun <T: View1> findViewById1(): T = null as T
+fun test1(): I = findViewById1()
+
+fun <T: View2> findViewById2(): T = null as T
+fun test2(): I = findViewById2()
+
+inline fun <reified T: View1> findViewById3(): T = null as T
+fun test3(): I = findViewById3()
+
+inline fun <reified T: View2> findViewById4(): T = null as T
+fun test4(): I = findViewById4()
+
+fun <T: View3> findViewById5(): T = null as T
+fun test5(): I = findViewById5()
+
+inline fun <reified T: View3> findViewById6(): T = null as T
+fun test6(): I = findViewById6()
+
+fun <T: View4> findViewById7(): T = null as T
+fun test7(): I = findViewById7()
+
+inline fun <reified T: View4> findViewById8(): T = null as T
+fun test8(): I = findViewById8()
+
+fun <T> findViewById9(): T where T: View3, T: View5 = null as T
+fun test9(): I = findViewById9()
+
+inline fun <reified T> findViewById10(): T where T: View3, T: View5 = null as T
+fun test10(): I = findViewById10()
+
+fun <T: View2> findViewById11(): T = null as T
+fun test11(): View4 = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>findViewById11<!>()
+
+object Obj {
+    fun <T: I> findViewById1(): T = null as T
+    fun test1(): View1 = findViewById1()
+
+    fun <T: I> findViewById2(): T = null as T
+    fun test2(): View2 = findViewById2()
+
+    inline fun <reified T: I> findViewById3(): T = null as T
+    fun test3(): View1 = findViewById3()
+
+    inline fun <reified T: I> findViewById4(): T = null as T
+    fun test4(): View2 = findViewById4()
+
+    fun <T: I> findViewById5(): T = null as T
+    fun test5(): View3 = findViewById5()
+
+    inline fun <reified T: I> findViewById6(): T = null as T
+    fun test6(): View3 = findViewById6()
+
+    fun <T: I> findViewById7(): T = null as T
+    fun test7(): View4 = findViewById7()
+
+    inline fun <reified T: I> findViewById8(): T = null as T
+    fun test8(): View4 = findViewById8()
+
+    fun <T> findViewById9(): T where T: View3, T: View5 = null as T
+    fun test9(): View1 = findViewById9()
+
+    inline fun <reified T> findViewById10(): T where T: View3, T: View5 = null as T
+    fun test10(): View1 = findViewById10()
+
+    fun <T: View2> findViewById11(): T = null as T
+    fun test11(): View4 = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>findViewById11<!>()
+}
+
+interface A
+open class B {
+    fun <T> f(): T where T : A, T : B = null as T
+    fun g(): A = f()
+}
diff --git a/compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.kt b/compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.kt
new file mode 100644
index 00000000000..837a6af8d37
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.kt
@@ -0,0 +1,84 @@
+// !DIAGNOSTICS: -FINAL_UPPER_BOUND -CAST_NEVER_SUCCEEDS
+// !LANGUAGE: +AllowEmptyIntersectionsInResultTypeResolver
+
+interface I
+
+class View1
+open class View2
+interface View3
+abstract class View4
+interface View5
+
+fun <T: View1> findViewById1(): T = null as T
+fun test1(): I = <!INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION!>findViewById1<!>()
+
+fun <T: View2> findViewById2(): T = null as T
+fun test2(): I = findViewById2()
+
+inline fun <reified T: View1> findViewById3(): T = null as T
+fun test3(): I = <!INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION!>findViewById3<!>()
+
+inline fun <reified T: View2> findViewById4(): T = null as T
+fun test4(): I = findViewById4()
+
+fun <T: View3> findViewById5(): T = null as T
+fun test5(): I = findViewById5()
+
+inline fun <reified T: View3> findViewById6(): T = null as T
+fun test6(): I = findViewById6()
+
+fun <T: View4> findViewById7(): T = null as T
+fun test7(): I = findViewById7()
+
+inline fun <reified T: View4> findViewById8(): T = null as T
+fun test8(): I = findViewById8()
+
+fun <T> findViewById9(): T where T: View3, T: View5 = null as T
+fun test9(): I = findViewById9()
+
+inline fun <reified T> findViewById10(): T where T: View3, T: View5 = null as T
+fun test10(): I = findViewById10()
+
+fun <T: View2> findViewById11(): T = null as T
+fun test11(): View4 = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>findViewById11<!>()
+
+object Obj {
+    fun <T: I> findViewById1(): T = null as T
+    fun test1(): View1 = <!INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION!>findViewById1<!>()
+
+    fun <T: I> findViewById2(): T = null as T
+    fun test2(): View2 = findViewById2()
+
+    inline fun <reified T: I> findViewById3(): T = null as T
+    fun test3(): View1 = <!INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION!>findViewById3<!>()
+
+    inline fun <reified T: I> findViewById4(): T = null as T
+    fun test4(): View2 = findViewById4()
+
+    fun <T: I> findViewById5(): T = null as T
+    fun test5(): View3 = findViewById5()
+
+    inline fun <reified T: I> findViewById6(): T = null as T
+    fun test6(): View3 = findViewById6()
+
+    fun <T: I> findViewById7(): T = null as T
+    fun test7(): View4 = findViewById7()
+
+    inline fun <reified T: I> findViewById8(): T = null as T
+    fun test8(): View4 = findViewById8()
+
+    fun <T> findViewById9(): T where T: View3, T: View5 = null as T
+    fun test9(): View1 = <!INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION!>findViewById9<!>()
+
+    inline fun <reified T> findViewById10(): T where T: View3, T: View5 = null as T
+    fun test10(): View1 = <!INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION!>findViewById10<!>()
+
+    fun <T: View2> findViewById11(): T = null as T
+    fun test11(): View4 = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>findViewById11<!>()
+}
+
+interface A
+open class B {
+    fun <T> f(): T where T : A, T : B = null as T
+    fun g(): A = f()
+}
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
index 0924959ee55..f855b393b02 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java
@@ -33490,6 +33490,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/typeParameters/kt46186.kt");
             }
 
+            @Test
+            @TestMetadata("kt46186withEmptyIntersections.kt")
+            public void testKt46186withEmptyIntersections() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.kt");
+            }
+
             @Test
             @TestMetadata("misplacedConstraints.kt")
             public void testMisplacedConstraints() throws Exception {
diff --git a/compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt b/compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt
index 98ddea28b21..bba4b444bdc 100644
--- a/compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt
+++ b/compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt
@@ -284,6 +284,7 @@ enum class LanguageFeature(
     // 2.0
 
     EnhanceNullabilityOfPrimitiveArrays(KOTLIN_2_0, kind = BUG_FIX), // KT-54521
+    AllowEmptyIntersectionsInResultTypeResolver(KOTLIN_2_0, kind = OTHER), // KT-51221
 
     // End of 2.* language features --------------------------------------------------