diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
index ef209e6a011..7ae3f1bf26a 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java
@@ -3609,6 +3609,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                 runTest("compiler/testData/diagnostics/tests/cast/FlexibleTargetType.kt");
             }
 
+            @Test
+            @TestMetadata("isAlwaysFalse.kt")
+            public void testIsAlwaysFalse() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/cast/isAlwaysFalse.kt");
+            }
+
             @Test
             @TestMetadata("IsErasedAllowForDerivedWithOneSubstitutedAndOneSameGeneric.kt")
             public void testIsErasedAllowForDerivedWithOneSubstitutedAndOneSameGeneric() throws Exception {
diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java
index 8736daf741f..f1fb0b0d323 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java
@@ -3609,6 +3609,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                 runTest("compiler/testData/diagnostics/tests/cast/FlexibleTargetType.kt");
             }
 
+            @Test
+            @TestMetadata("isAlwaysFalse.kt")
+            public void testIsAlwaysFalse() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/cast/isAlwaysFalse.kt");
+            }
+
             @Test
             @TestMetadata("IsErasedAllowForDerivedWithOneSubstitutedAndOneSameGeneric.kt")
             public void testIsErasedAllowForDerivedWithOneSubstitutedAndOneSameGeneric() throws Exception {
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/types/expressions/PatternMatchingTypingVisitor.kt b/compiler/frontend/src/org/jetbrains/kotlin/types/expressions/PatternMatchingTypingVisitor.kt
index 9e1e6bb5a71..4ea4dbe815b 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/types/expressions/PatternMatchingTypingVisitor.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/types/expressions/PatternMatchingTypingVisitor.kt
@@ -43,6 +43,7 @@ import org.jetbrains.kotlin.types.expressions.ControlStructureTypingUtils.*
 import org.jetbrains.kotlin.types.expressions.typeInfoFactory.createTypeInfo
 import org.jetbrains.kotlin.types.expressions.typeInfoFactory.noTypeInfo
 import org.jetbrains.kotlin.types.typeUtil.containsError
+import org.jetbrains.kotlin.types.typeUtil.isAnyOrNullableAny
 import java.util.*
 
 class PatternMatchingTypingVisitor internal constructor(facade: ExpressionTypingInternals) : ExpressionTypingVisitor(facade) {
@@ -640,9 +641,9 @@ class PatternMatchingTypingVisitor internal constructor(facade: ExpressionTyping
             assert(element is KtNullableType) { "element must be instance of " + KtNullableType::class.java.name }
             context.trace.report(Errors.USELESS_NULLABLE_CHECK.on(element as KtNullableType))
         }
-        checkTypeCompatibility(context, targetType, subjectType, typeReferenceAfterIs)
+        val typesAreCompatible = checkTypeCompatibility(context, targetType, subjectType, typeReferenceAfterIs)
 
-        detectRedundantIs(context, subjectType, targetType, isCheck, negated, subjectDataFlowValue)
+        detectRedundantIs(context, subjectType, targetType, isCheck, negated, subjectDataFlowValue, typesAreCompatible)
 
         if (context.languageVersionSettings.supportsFeature(LanguageFeature.ProperCheckAnnotationsTargetInTypeUsePositions)) {
             components.annotationChecker.check(typeReferenceAfterIs, context.trace)
@@ -662,12 +663,24 @@ class PatternMatchingTypingVisitor internal constructor(facade: ExpressionTyping
         targetType: KotlinType,
         isCheck: KtElement,
         negated: Boolean,
-        subjectDataFlowValue: DataFlowValue
+        subjectDataFlowValue: DataFlowValue,
+        typesAreCompatible: Boolean
     ) {
         if (subjectType.containsError() || targetType.containsError()) return
 
         val possibleTypes =
             DataFlowAnalyzer.getAllPossibleTypes(subjectType, context, subjectDataFlowValue, context.languageVersionSettings)
+
+        if (typesAreCompatible && !targetType.isError) {
+            val nonTrivialTypes = possibleTypes.filterNot { it.isAnyOrNullableAny() }
+                .takeIf { it.isNotEmpty() }
+                ?: possibleTypes
+
+            if (nonTrivialTypes.none { CastDiagnosticsUtil.isCastPossible(it, targetType, components.platformToKotlinClassMapper) }) {
+                context.trace.report(USELESS_IS_CHECK.on(isCheck, negated))
+            }
+        }
+
         if (CastDiagnosticsUtil.isRefinementUseless(possibleTypes, targetType, false)) {
             context.trace.report(Errors.USELESS_IS_CHECK.on(isCheck, !negated))
         }
@@ -683,11 +696,11 @@ class PatternMatchingTypingVisitor internal constructor(facade: ExpressionTyping
         type: KotlinType,
         subjectType: KotlinType,
         reportErrorOn: KtElement
-    ) {
+    ): Boolean {
         // TODO : Take smart casts into account?
         if (TypeIntersector.isIntersectionEmpty(type, subjectType)) {
             context.trace.report(INCOMPATIBLE_TYPES.on(reportErrorOn, type, subjectType))
-            return
+            return false
         }
 
         checkEnumsForCompatibility(context, reportErrorOn, subjectType, type)
@@ -696,5 +709,6 @@ class PatternMatchingTypingVisitor internal constructor(facade: ExpressionTyping
         if (KotlinBuiltIns.isNullableNothing(type) && !TypeUtils.isNullableType(subjectType)) {
             context.trace.report(SENSELESS_NULL_IN_WHEN.on(reportErrorOn))
         }
+        return true
     }
 }
diff --git a/compiler/testData/diagnostics/tests/cast/IsRecursionSustainable.kt b/compiler/testData/diagnostics/tests/cast/IsRecursionSustainable.kt
index 73faa4af355..bc3b65f5a76 100644
--- a/compiler/testData/diagnostics/tests/cast/IsRecursionSustainable.kt
+++ b/compiler/testData/diagnostics/tests/cast/IsRecursionSustainable.kt
@@ -2,5 +2,5 @@ open class RecA<T>: <!CYCLIC_INHERITANCE_HIERARCHY!>RecB<T><!>()
 open class RecB<T>: <!CYCLIC_INHERITANCE_HIERARCHY!>RecA<T><!>()
 open class SelfR<T>: <!CYCLIC_INHERITANCE_HIERARCHY!>SelfR<T><!>()
 
-fun test(f: SelfR<String>) = f is <!CANNOT_CHECK_FOR_ERASED!>RecA<String><!>
-fun test(f: RecB<String>) = f is <!CANNOT_CHECK_FOR_ERASED!>RecA<String><!>
\ No newline at end of file
+fun test(f: SelfR<String>) = <!USELESS_IS_CHECK!>f is <!CANNOT_CHECK_FOR_ERASED!>RecA<String><!><!>
+fun test(f: RecB<String>) = <!USELESS_IS_CHECK!>f is <!CANNOT_CHECK_FOR_ERASED!>RecA<String><!><!>
diff --git a/compiler/testData/diagnostics/tests/cast/isAlwaysFalse.fir.kt b/compiler/testData/diagnostics/tests/cast/isAlwaysFalse.fir.kt
new file mode 100644
index 00000000000..6db19aa1458
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/cast/isAlwaysFalse.fir.kt
@@ -0,0 +1,69 @@
+abstract class A
+abstract class B : A()
+
+abstract class AS
+abstract class BS : AS()
+
+interface AI
+interface BI : AI
+
+fun test_1(a: A) {
+    <!USELESS_IS_CHECK!>a is A<!> // always true
+    a is B
+
+    a is AS // always false
+    a is BS // always false
+
+    a is AI
+    a is BI
+}
+
+fun test_2(a: A) {
+    <!USELESS_IS_CHECK!>a !is A<!> // always false
+    a !is B
+
+    a !is AS // always true
+    a !is BS // always true
+
+    a !is AI
+    a !is BI
+}
+
+fun test_3(a: Any) {
+    if (a is A) {
+        <!USELESS_IS_CHECK!>a is A<!> // always true
+        a is B
+
+        a is AS // always false
+        a is BS // always false
+
+        a is AI
+        a is BI
+    }
+}
+
+fun test_4(a: A) {
+    when (a) {
+        <!USELESS_IS_CHECK!>is A<!> -> {} // always true
+        is B -> {}
+
+        is AS -> {} // always false
+        is BS -> {} // always false
+
+        is AI -> {}
+        is BI -> {}
+    }
+}
+
+fun test_5(a: A) {
+    when (a) {
+        <!USELESS_IS_CHECK!>!is A<!> -> {} // always false
+        !is B -> {}
+
+        !is AS -> {} // always true
+        !is BS -> {} // here a may has type AS (by data flow)
+
+        !is AI -> {}
+        !is BI -> {}
+    }
+}
diff --git a/compiler/testData/diagnostics/tests/cast/isAlwaysFalse.kt b/compiler/testData/diagnostics/tests/cast/isAlwaysFalse.kt
new file mode 100644
index 00000000000..8813b9ea556
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/cast/isAlwaysFalse.kt
@@ -0,0 +1,69 @@
+abstract class A
+abstract class B : A()
+
+abstract class AS
+abstract class BS : AS()
+
+interface AI
+interface BI : AI
+
+fun test_1(a: A) {
+    <!USELESS_IS_CHECK("true")!>a is A<!> // always true
+    a is B
+
+    <!USELESS_IS_CHECK("false")!>a is AS<!> // always false
+    <!USELESS_IS_CHECK("false")!>a is BS<!> // always false
+
+    a is AI
+    a is BI
+}
+
+fun test_2(a: A) {
+    <!USELESS_IS_CHECK("false")!>a !is A<!> // always false
+    a !is B
+
+    <!USELESS_IS_CHECK("true")!>a !is AS<!> // always true
+    <!USELESS_IS_CHECK("true")!>a !is BS<!> // always true
+
+    a !is AI
+    a !is BI
+}
+
+fun test_3(a: Any) {
+    if (a is A) {
+        <!USELESS_IS_CHECK("true")!>a is A<!> // always true
+        a is B
+
+        <!USELESS_IS_CHECK("false")!>a is AS<!> // always false
+        <!USELESS_IS_CHECK("false")!>a is BS<!> // always false
+
+        a is AI
+        a is BI
+    }
+}
+
+fun test_4(a: A) {
+    when (a) {
+        <!USELESS_IS_CHECK("true")!>is A<!> -> {} // always true
+        is B -> {}
+
+        <!USELESS_IS_CHECK("false")!>is AS<!> -> {} // always false
+        <!USELESS_IS_CHECK("false")!>is BS<!> -> {} // always false
+
+        is AI -> {}
+        is BI -> {}
+    }
+}
+
+fun test_5(a: A) {
+    when (a) {
+        <!USELESS_IS_CHECK("false")!>!is A<!> -> {} // always false
+        !is B -> {}
+
+        <!USELESS_IS_CHECK("true")!>!is AS<!> -> {} // always true
+        !is BS -> {} // here a may has type AS (by data flow)
+
+        !is AI -> {}
+        !is BI -> {}
+    }
+}
diff --git a/compiler/testData/diagnostics/tests/cast/isAlwaysFalse.txt b/compiler/testData/diagnostics/tests/cast/isAlwaysFalse.txt
new file mode 100644
index 00000000000..4db3603922b
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/cast/isAlwaysFalse.txt
@@ -0,0 +1,48 @@
+package
+
+public fun test_1(/*0*/ a: A): kotlin.Unit
+public fun test_2(/*0*/ a: A): kotlin.Unit
+public fun test_3(/*0*/ a: kotlin.Any): kotlin.Unit
+public fun test_4(/*0*/ a: A): kotlin.Unit
+public fun test_5(/*0*/ a: A): kotlin.Unit
+
+public abstract class A {
+    public constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface AI {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public abstract class AS {
+    public constructor AS()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public abstract class B : A {
+    public constructor B()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface BI : AI {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public abstract class BS : AS {
+    public constructor BS()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
diff --git a/compiler/testData/diagnostics/tests/dataFlowInfoTraversal/smartcasts/SmartcastAmbiguitites.kt b/compiler/testData/diagnostics/tests/dataFlowInfoTraversal/smartcasts/SmartcastAmbiguitites.kt
index fd62c2ebc16..96a371f1847 100644
--- a/compiler/testData/diagnostics/tests/dataFlowInfoTraversal/smartcasts/SmartcastAmbiguitites.kt
+++ b/compiler/testData/diagnostics/tests/dataFlowInfoTraversal/smartcasts/SmartcastAmbiguitites.kt
@@ -9,7 +9,7 @@ class C() {
 
 fun test(a : Any?) {
   if (a is B) {
-      if (a is C) {
+      if (<!USELESS_IS_CHECK!>a is C<!>) {
           <!DEBUG_INFO_SMARTCAST!>a<!>.bar();
       }
   }
diff --git a/compiler/testData/diagnostics/tests/enum/enumSubjectTypeCheck.kt b/compiler/testData/diagnostics/tests/enum/enumSubjectTypeCheck.kt
index 5ef20809c8d..8254a0ab915 100644
--- a/compiler/testData/diagnostics/tests/enum/enumSubjectTypeCheck.kt
+++ b/compiler/testData/diagnostics/tests/enum/enumSubjectTypeCheck.kt
@@ -30,11 +30,11 @@ fun useEn(x: En) = x
 fun useEn2(x: En2) = x
 
 fun bar(x: Any) {
-    if (x is En && x is En2) {
+    if (x is En && <!USELESS_IS_CHECK!>x is En2<!>) {
         when (<!DEBUG_INFO_SMARTCAST!>x<!>) {
             En.A -> useEn(<!DEBUG_INFO_SMARTCAST!>x<!>)
             En2.D -> useEn2(<!DEBUG_INFO_SMARTCAST!>x<!>)
             else -> {}
         }
     }
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/diagnostics/tests/regressions/kt6508.kt b/compiler/testData/diagnostics/tests/regressions/kt6508.kt
index 8ac37083d04..edb38065903 100644
--- a/compiler/testData/diagnostics/tests/regressions/kt6508.kt
+++ b/compiler/testData/diagnostics/tests/regressions/kt6508.kt
@@ -22,4 +22,4 @@ fun String.gah(view:View ?) {
     if (view is <!UNRESOLVED_REFERENCE!>TextView<!>)
         view
     else <!UNRESOLVED_REFERENCE!>TextView<!>() as foo.TextView
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/diagnostics/tests/scopes/stopResolutionOnAmbiguity.kt b/compiler/testData/diagnostics/tests/scopes/stopResolutionOnAmbiguity.kt
index e0cb029626f..c7b2321c37f 100644
--- a/compiler/testData/diagnostics/tests/scopes/stopResolutionOnAmbiguity.kt
+++ b/compiler/testData/diagnostics/tests/scopes/stopResolutionOnAmbiguity.kt
@@ -11,7 +11,7 @@ class C() {
 
 fun test(a : Any?) {
     if (a is B) {
-        if (a is C) {
+        if (<!USELESS_IS_CHECK!>a is C<!>) {
             <!DEBUG_INFO_SMARTCAST!>a<!>.bar();
         }
     }
diff --git a/compiler/testData/diagnostics/tests/when/intersectionExhaustivenessComplex.kt b/compiler/testData/diagnostics/tests/when/intersectionExhaustivenessComplex.kt
index 3c2ad18612a..63c2b1ed217 100644
--- a/compiler/testData/diagnostics/tests/when/intersectionExhaustivenessComplex.kt
+++ b/compiler/testData/diagnostics/tests/when/intersectionExhaustivenessComplex.kt
@@ -11,7 +11,7 @@ sealed class B {
 }
 
 fun foo(a: A) {
-    if (a !is B) return
+    if (<!USELESS_IS_CHECK!>a !is B<!>) return
 
     <!NO_ELSE_IN_WHEN!>when<!> (<!DEBUG_INFO_SMARTCAST!>a<!>) {
         is A.A1 -> ""
diff --git a/compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/deeplyNested.kt b/compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/deeplyNested.kt
index e90d2f1664e..b5e5353608e 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/deeplyNested.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/deeplyNested.kt
@@ -78,7 +78,7 @@ fun branchedAndNested(x: Any?, y: Any?) {
 
 
 fun br(y: Any?) {
-    if (myAssert(y is Int) == Unit && myAssert(y is String) == Unit) {
+    if (myAssert(y is Int) == Unit && myAssert(<!USELESS_IS_CHECK!>y is String<!>) == Unit) {
         <!DEBUG_INFO_SMARTCAST!>y<!>.length
         <!DEBUG_INFO_SMARTCAST!>y<!>.inc()
     }
@@ -89,7 +89,7 @@ fun branchedAndNestedWithNativeOperators(x: Any?, y: Any?) {
             equalsTrue(notEqualsNull(nullWhenNotString(x)))   // x is String
             &&
             (
-                    (myAssert(y is Int) == Unit && myAssert(y is String) == Unit)  // y is Int, String
+                    (myAssert(y is Int) == Unit && myAssert(<!USELESS_IS_CHECK!>y is String<!>) == Unit)  // y is Int, String
                     ||
                     equalsTrue(isInt(y) && isString(y))                          // y is Int, String
             )
diff --git a/compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/intersectingInfo.kt b/compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/intersectingInfo.kt
index a2ec7f07bde..91f928dd872 100644
--- a/compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/intersectingInfo.kt
+++ b/compiler/testData/diagnostics/testsWithStdLib/contracts/smartcasts/intersectingInfo.kt
@@ -45,8 +45,8 @@ fun intersectingInfo2(x: Any?, y: Any?) {
     // of them is absent in each arg of "||"-operator, so they *shouldn't* lead to smartcast
 
     if ((isString(x) && !notIsInt(x) && y is String) ||
-        (!notIsString(x) && isString(y) && y is Int) ||
-        (x is String && !notIsInt(y) && x is Int)) {
+        (!notIsString(x) && isString(y) && <!USELESS_IS_CHECK!>y is Int<!>) ||
+        (x is String && !notIsInt(y) && <!USELESS_IS_CHECK!>x is Int<!>)) {
         <!DEBUG_INFO_SMARTCAST!>x<!>.length
         x.<!UNRESOLVED_REFERENCE_WRONG_RECEIVER!>inc<!>()
         y.<!UNRESOLVED_REFERENCE!>length<!>
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 34ef749cadc..b51151d8835 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
@@ -3615,6 +3615,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/cast/FlexibleTargetType.kt");
             }
 
+            @Test
+            @TestMetadata("isAlwaysFalse.kt")
+            public void testIsAlwaysFalse() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/cast/isAlwaysFalse.kt");
+            }
+
             @Test
             @TestMetadata("IsErasedAllowForDerivedWithOneSubstitutedAndOneSameGeneric.kt")
             public void testIsErasedAllowForDerivedWithOneSubstitutedAndOneSameGeneric() throws Exception {
diff --git a/compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/p-2/pos/2.1.kt b/compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/p-2/pos/2.1.kt
index 2647f5bfff6..d4221fb246e 100644
--- a/compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/p-2/pos/2.1.kt
+++ b/compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/p-2/pos/2.1.kt
@@ -77,7 +77,7 @@ fun case_5(value_1: Boolean) {
 // TESTCASE NUMBER: 6
 fun case_6(value_1: Any) {
     when {
-        value_1 is Nothing -> {}
+        <!USELESS_IS_CHECK!>value_1 is Nothing<!> -> {}
         value_1 is Int -> {}
         value_1 is Boolean -> {}
         value_1 is String -> {}
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/smartcasts/pos/9.kt b/compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/smartcasts/pos/9.kt
index 5e4c42bd952..c4888e2fd50 100644
--- a/compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/smartcasts/pos/9.kt
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/smartcasts/pos/9.kt
@@ -108,7 +108,7 @@ fun case_8(value_1: Any?) {
 
 // TESTCASE NUMBER: 9
 fun case_9(value_1: Any?) {
-    if (funWithReturnsFalse(value_1 is String) || funWithReturnsFalse(value_1 is Int)) {
+    if (funWithReturnsFalse(value_1 is String) || funWithReturnsFalse(<!USELESS_IS_CHECK!>value_1 is Int<!>)) {
 
     } else {
         println(<!DEBUG_INFO_SMARTCAST!>value_1<!>.length)
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractBuilder/effects/returns/neg/6.kt b/compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractBuilder/effects/returns/neg/6.kt
index c6fe07e0d66..7bb62978635 100644
--- a/compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractBuilder/effects/returns/neg/6.kt
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractBuilder/effects/returns/neg/6.kt
@@ -18,8 +18,8 @@ fun Boolean?.case_1(): Boolean {
 
 // TESTCASE NUMBER: 2
 fun <T : <!FINAL_UPPER_BOUND!>Boolean<!>>T?.case_2(): Boolean {
-    <!ERROR_IN_CONTRACT_DESCRIPTION!>contract<!> { returns(true) implies (this@case_2 != null && this@case_2 !is Nothing && <!DEBUG_INFO_SMARTCAST!>this@case_2<!>) }
-    return this != null && this !is Nothing && <!DEBUG_INFO_SMARTCAST!>this<!>
+    <!ERROR_IN_CONTRACT_DESCRIPTION!>contract<!> { returns(true) implies (this@case_2 != null && <!USELESS_IS_CHECK!>this@case_2 !is Nothing<!> && <!DEBUG_INFO_SMARTCAST!>this@case_2<!>) }
+    return this != null && <!USELESS_IS_CHECK!>this !is Nothing<!> && <!DEBUG_INFO_SMARTCAST!>this<!>
 }
 
 // TESTCASE NUMBER: 3
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractFunction/neg/2.kt b/compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractFunction/neg/2.kt
index 0552a6e775d..08b9e5c0b2d 100644
--- a/compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractFunction/neg/2.kt
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/contracts/declarations/contractFunction/neg/2.kt
@@ -70,13 +70,13 @@ class case_4 : ClassLevel3() {
 class case_5<T> : ClassLevel5() {
     inner class case_5_1 {
         fun <K : Number?>K.case_5_1_1() {
-            contract { returns() implies (<!ERROR_IN_CONTRACT_DESCRIPTION!>this@case_5_1<!> !is ClassLevel1 && <!SENSELESS_COMPARISON!>this@case_5_1 != null<!> || <!USELESS_IS_CHECK!>this@case_5 is ClassLevel1<!> && this@case_5_1_1 is Float) }
-            if (!(this@case_5_1 !is ClassLevel1 && <!SENSELESS_COMPARISON!>this@case_5_1 != null<!> || <!USELESS_IS_CHECK!>this@case_5 is ClassLevel1<!> && this is Float)) throw Exception()
+            contract { returns() implies (<!USELESS_IS_CHECK!><!ERROR_IN_CONTRACT_DESCRIPTION!>this@case_5_1<!> !is ClassLevel1<!> && <!SENSELESS_COMPARISON!>this@case_5_1 != null<!> || <!USELESS_IS_CHECK!>this@case_5 is ClassLevel1<!> && this@case_5_1_1 is Float) }
+            if (!(<!USELESS_IS_CHECK!>this@case_5_1 !is ClassLevel1<!> && <!SENSELESS_COMPARISON!>this@case_5_1 != null<!> || <!USELESS_IS_CHECK!>this@case_5 is ClassLevel1<!> && this is Float)) throw Exception()
         }
 
         fun case_5_1_2() {
-            contract { returns() implies (this@case_5_1 !is ClassLevel1 || <!USELESS_IS_CHECK!><!ERROR_IN_CONTRACT_DESCRIPTION!>this@case_5<!> is ClassLevel1<!> || <!SENSELESS_COMPARISON!>this@case_5_1 == null<!>) }
-            if (!(this@case_5_1 !is ClassLevel1 || <!USELESS_IS_CHECK!>this@case_5 is ClassLevel1<!> || <!SENSELESS_COMPARISON!>this@case_5_1 == null<!>)) throw Exception()
+            contract { returns() implies (<!USELESS_IS_CHECK!>this@case_5_1 !is ClassLevel1<!> || <!USELESS_IS_CHECK!><!ERROR_IN_CONTRACT_DESCRIPTION!>this@case_5<!> is ClassLevel1<!> || <!SENSELESS_COMPARISON!>this@case_5_1 == null<!>) }
+            if (!(<!USELESS_IS_CHECK!>this@case_5_1 !is ClassLevel1<!> || <!USELESS_IS_CHECK!>this@case_5 is ClassLevel1<!> || <!SENSELESS_COMPARISON!>this@case_5_1 == null<!>)) throw Exception()
         }
     }
 }
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/1.kt b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/1.kt
index b7769e9c723..26e1a5fe60e 100644
--- a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/1.kt
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/1.kt
@@ -14,7 +14,7 @@
 
 // TESTCASE NUMBER: 1
 fun case_1(x: Any?) {
-    if (x != null is Boolean) {
+    if (x != <!USELESS_IS_CHECK!>null is Boolean<!>) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any?")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any?")!>x<!><!UNSAFE_CALL!>.<!>equals(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any?")!>x<!>.propT
@@ -97,7 +97,7 @@ fun case_6(x: EmptyClass?) {
 
 // TESTCASE NUMBER: 7
 fun case_7() {
-    if (nullableNumberProperty != null || <!EQUALITY_NOT_APPLICABLE!><!DEBUG_INFO_CONSTANT, DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing? & kotlin.Number?")!>nullableNumberProperty<!> != null is Boolean<!>) {
+    if (nullableNumberProperty != null || <!EQUALITY_NOT_APPLICABLE!><!DEBUG_INFO_CONSTANT, DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing? & kotlin.Number?")!>nullableNumberProperty<!> != <!USELESS_IS_CHECK!>null is Boolean<!><!>) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number?")!>nullableNumberProperty<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number?")!>nullableNumberProperty<!><!UNSAFE_CALL!>.<!>equals(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number?")!>nullableNumberProperty<!>.propT
@@ -151,12 +151,12 @@ fun case_10() {
 fun case_11(x: TypealiasNullableStringIndirect<!REDUNDANT_NULLABLE!>?<!>, y: TypealiasNullableStringIndirect) {
     val t: TypealiasNullableStringIndirect = null
 
-    if (<!EQUALITY_NOT_APPLICABLE!>x == null is Boolean<!>) {
+    if (<!EQUALITY_NOT_APPLICABLE!>x == <!USELESS_IS_CHECK!>null is Boolean<!><!>) {
 
     } else {
-        if (<!EQUALITY_NOT_APPLICABLE!>y != null is Boolean<!> == true) {
+        if (<!EQUALITY_NOT_APPLICABLE!>y != <!USELESS_IS_CHECK!>null is Boolean<!><!> == true) {
             if (<!USELESS_IS_CHECK!>(nullableStringProperty == null) !is Boolean<!>) {
-                if (<!EQUALITY_NOT_APPLICABLE!>t != null is Boolean<!>) {
+                if (<!EQUALITY_NOT_APPLICABLE!>t != <!USELESS_IS_CHECK!>null is Boolean<!><!>) {
                     <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableStringIndirect? /* = kotlin.String? */")!>x<!>
                     <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableStringIndirect? /* = kotlin.String? */")!>x<!>.equals(null)
                     <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableStringIndirect? /* = kotlin.String? */")!>x<!>.propT
@@ -190,7 +190,7 @@ fun case_12(x: TypealiasNullableStringIndirect, y: TypealiasNullableStringIndire
 
 // TESTCASE NUMBER: 13
 fun <!IMPLICIT_NOTHING_RETURN_TYPE!>case_13<!>(x: <!UNRESOLVED_REFERENCE!>otherpackage<!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>Case13<!>?) =
-    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing")!>if (<!DEPRECATED_IDENTITY_EQUALS!>(<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>==<!> null !is Boolean) !== true<!>) {
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing")!>if (<!DEPRECATED_IDENTITY_EQUALS!>(<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>==<!> <!USELESS_IS_CHECK!>null !is Boolean<!>) !== true<!>) {
         throw Exception()
     } else {
         <!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, DEBUG_INFO_EXPRESSION_TYPE("[ERROR : otherpackage.Case13]?")!>x<!>
@@ -208,7 +208,7 @@ class Case14 {
 fun case_14() {
     val a = Case14()
 
-    if (a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> <!USELESS_IS_CHECK!>null !is Boolean !is Boolean<!>) {
+    if (a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> <!USELESS_IS_CHECK!><!USELESS_IS_CHECK!>null !is Boolean<!> !is Boolean<!>) {
         if (a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> null == true) {
             if (a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> !== null == false) {
                 if (<!SENSELESS_COMPARISON!>a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> null == null<!>) {
@@ -219,11 +219,11 @@ fun case_14() {
                                     if (<!DEPRECATED_IDENTITY_EQUALS!>a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> null === false<!>) {
                                         if (<!DEPRECATED_IDENTITY_EQUALS!>a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> !== null === true<!>) {
                                             if (<!USELESS_IS_CHECK!>(a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> null != true) !is Boolean<!>) {
-                                                if (a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> null is Boolean) {
-                                                    if (a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> <!USELESS_IS_CHECK!>null is Boolean is Boolean<!>) {
-                                                        if (<!IMPLICIT_BOXING_IN_IDENTITY_EQUALS!>a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> !== null is Boolean<!>) {
-                                                            if (a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> null is Boolean) {
-                                                                if ((<!IMPLICIT_BOXING_IN_IDENTITY_EQUALS!>a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> !== null !is Boolean<!>) == false) {
+                                                if (a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> <!USELESS_IS_CHECK!>null is Boolean<!>) {
+                                                    if (a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> <!USELESS_IS_CHECK!><!USELESS_IS_CHECK!>null is Boolean<!> is Boolean<!>) {
+                                                        if (<!IMPLICIT_BOXING_IN_IDENTITY_EQUALS!>a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> !== <!USELESS_IS_CHECK!>null is Boolean<!><!>) {
+                                                            if (a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> <!DEBUG_INFO_MISSING_UNRESOLVED!>!=<!> <!USELESS_IS_CHECK!>null is Boolean<!>) {
+                                                                if ((<!IMPLICIT_BOXING_IN_IDENTITY_EQUALS!>a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!> !== <!USELESS_IS_CHECK!>null !is Boolean<!><!>) == false) {
                                                                     <!DEBUG_INFO_EXPRESSION_TYPE("[ERROR : otherpackage.Case14]?")!>a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!><!>
                                                                     <!DEBUG_INFO_EXPRESSION_TYPE("[ERROR : otherpackage.Case14]?")!>a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!><!>.<!DEBUG_INFO_MISSING_UNRESOLVED!>equals<!>(a.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>x<!>)
                                                                 }
@@ -246,7 +246,7 @@ fun case_14() {
 
 // TESTCASE NUMBER: 15
 fun case_15(x: EmptyObject) {
-    val <!UNUSED_VARIABLE!>t<!> = if (<!EQUALITY_NOT_APPLICABLE!>x === <!USELESS_IS_CHECK!><!USELESS_IS_CHECK!>null is Boolean is Boolean<!> is Boolean<!><!>) "" else {
+    val <!UNUSED_VARIABLE!>t<!> = if (<!EQUALITY_NOT_APPLICABLE!>x === <!USELESS_IS_CHECK!><!USELESS_IS_CHECK!><!USELESS_IS_CHECK!>null is Boolean<!> is Boolean<!> is Boolean<!><!>) "" else {
         <!DEBUG_INFO_EXPRESSION_TYPE("EmptyObject")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("EmptyObject")!>x<!>.equals(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("EmptyObject")!>x<!>.propT
@@ -264,7 +264,7 @@ fun case_15(x: EmptyObject) {
 fun case_16() {
     val x: TypealiasNullableNothing = null
 
-    if (<!DEBUG_INFO_CONSTANT!>x<!> != <!USELESS_IS_CHECK!><!USELESS_IS_CHECK!><!USELESS_IS_CHECK!><!USELESS_IS_CHECK!>null !is Boolean !is Boolean<!> !is Boolean<!> !is Boolean<!> !is Boolean<!>) {
+    if (<!DEBUG_INFO_CONSTANT!>x<!> != <!USELESS_IS_CHECK!><!USELESS_IS_CHECK!><!USELESS_IS_CHECK!><!USELESS_IS_CHECK!><!USELESS_IS_CHECK!>null !is Boolean<!> !is Boolean<!> !is Boolean<!> !is Boolean<!> !is Boolean<!>) {
         <!DEBUG_INFO_CONSTANT, DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableNothing /* = kotlin.Nothing? */")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("TypealiasNullableNothing /* = kotlin.Nothing? */")!>x<!><!UNSAFE_CALL!>.<!><!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE, NEW_INFERENCE_NO_INFORMATION_FOR_PARAMETER!>java<!>
     }
@@ -312,7 +312,7 @@ fun case_19(b: Boolean) {
         }
     } else null
 
-    if (<!EQUALITY_NOT_APPLICABLE!>a != null !is Boolean<!> && <!EQUALITY_NOT_APPLICABLE!>a<!UNSAFE_CALL!>.<!>B19 != null is Boolean<!> && <!EQUALITY_NOT_APPLICABLE!>a<!UNSAFE_CALL!>.<!>B19<!UNSAFE_CALL!>.<!>C19 != null is Boolean<!> && <!SENSELESS_COMPARISON!>a<!UNSAFE_CALL!>.<!>B19<!UNSAFE_CALL!>.<!>C19<!UNSAFE_CALL!>.<!>D19 != null == null<!> && <!SENSELESS_COMPARISON!>a<!UNSAFE_CALL!>.<!>B19<!UNSAFE_CALL!>.<!>C19<!UNSAFE_CALL!>.<!>D19<!UNSAFE_CALL!>.<!>x != null !== null<!>) {
+    if (<!EQUALITY_NOT_APPLICABLE!>a != <!USELESS_IS_CHECK!>null !is Boolean<!><!> && <!EQUALITY_NOT_APPLICABLE!>a<!UNSAFE_CALL!>.<!>B19 != <!USELESS_IS_CHECK!>null is Boolean<!><!> && <!EQUALITY_NOT_APPLICABLE!>a<!UNSAFE_CALL!>.<!>B19<!UNSAFE_CALL!>.<!>C19 != <!USELESS_IS_CHECK!>null is Boolean<!><!> && <!SENSELESS_COMPARISON!>a<!UNSAFE_CALL!>.<!>B19<!UNSAFE_CALL!>.<!>C19<!UNSAFE_CALL!>.<!>D19 != null == null<!> && <!SENSELESS_COMPARISON!>a<!UNSAFE_CALL!>.<!>B19<!UNSAFE_CALL!>.<!>C19<!UNSAFE_CALL!>.<!>D19<!UNSAFE_CALL!>.<!>x != null !== null<!>) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number?")!>a<!UNSAFE_CALL!>.<!>B19<!UNSAFE_CALL!>.<!>C19<!UNSAFE_CALL!>.<!>D19<!UNSAFE_CALL!>.<!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number?")!>a<!UNSAFE_CALL!>.<!>B19<!UNSAFE_CALL!>.<!>C19<!UNSAFE_CALL!>.<!>D19<!UNSAFE_CALL!>.<!>x<!><!UNSAFE_CALL!>.<!>equals(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number?")!>a<!UNSAFE_CALL!>.<!>B19<!UNSAFE_CALL!>.<!>C19<!UNSAFE_CALL!>.<!>D19<!UNSAFE_CALL!>.<!>x<!>.propT
@@ -338,7 +338,7 @@ fun case_20(b: Boolean) {
         }
     }
 
-    if (<!EQUALITY_NOT_APPLICABLE!>a.B19.C19.D19 !== null !is Boolean<!>) {
+    if (<!EQUALITY_NOT_APPLICABLE!>a.B19.C19.D19 !== <!USELESS_IS_CHECK!>null !is Boolean<!><!>) {
         <!DEBUG_INFO_EXPRESSION_TYPE("case_20.<no name provided>.B19.<no name provided>.C19.<no name provided>.D19.<no name provided>?")!>a.B19.C19.D19<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("case_20.<no name provided>.B19.<no name provided>.C19.<no name provided>.D19.<no name provided>?")!>a.B19.C19.D19<!><!UNSAFE_CALL!>.<!>equals(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("case_20.<no name provided>.B19.<no name provided>.C19.<no name provided>.D19.<no name provided>?")!>a.B19.C19.D19<!>.propT
@@ -354,7 +354,7 @@ fun case_20(b: Boolean) {
 
 // TESTCASE NUMBER: 21
 fun case_21() {
-    if (<!EQUALITY_NOT_APPLICABLE!>EnumClassWithNullableProperty.B.prop_1 !== null is Boolean<!> == <!USELESS_IS_CHECK!>true !is Boolean<!> != true) {
+    if (<!EQUALITY_NOT_APPLICABLE!>EnumClassWithNullableProperty.B.prop_1 !== <!USELESS_IS_CHECK!>null is Boolean<!><!> == <!USELESS_IS_CHECK!>true !is Boolean<!> != true) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>EnumClassWithNullableProperty.B.prop_1<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>EnumClassWithNullableProperty.B.prop_1<!><!UNSAFE_CALL!>.<!>equals(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!>EnumClassWithNullableProperty.B.prop_1<!>.propT
@@ -370,7 +370,7 @@ fun case_21() {
 
 // TESTCASE NUMBER: 22
 fun case_22(a: (() -> Unit)?) {
-    if (<!EQUALITY_NOT_APPLICABLE!>a != null !is Boolean<!>) {
+    if (<!EQUALITY_NOT_APPLICABLE!>a != <!USELESS_IS_CHECK!>null !is Boolean<!><!>) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Unit")!><!UNSAFE_IMPLICIT_INVOKE_CALL!>a<!>()<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Unit")!><!UNSAFE_IMPLICIT_INVOKE_CALL!>a<!>()<!>.equals(null)
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Unit")!><!UNSAFE_IMPLICIT_INVOKE_CALL!>a<!>()<!>.propT
@@ -386,7 +386,7 @@ fun case_22(a: (() -> Unit)?) {
 
 // TESTCASE NUMBER: 23
 fun case_23(a: ((Float) -> Int?)?, b: Float?) {
-    if (<!EQUALITY_NOT_APPLICABLE!>a != null !is Boolean<!> && <!EQUALITY_NOT_APPLICABLE!>b !== null is Boolean<!>) {
+    if (<!EQUALITY_NOT_APPLICABLE!>a != <!USELESS_IS_CHECK!>null !is Boolean<!><!> && <!EQUALITY_NOT_APPLICABLE!>b !== <!USELESS_IS_CHECK!>null is Boolean<!><!>) {
         val x = <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int?")!><!UNSAFE_IMPLICIT_INVOKE_CALL!>a<!>(<!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Float?"), TYPE_MISMATCH!>b<!>)<!>
         if (x != null) {
             <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int & kotlin.Int?")!>x<!>
@@ -405,7 +405,7 @@ fun case_23(a: ((Float) -> Int?)?, b: Float?) {
 
 // TESTCASE NUMBER: 24
 fun case_24(a: ((() -> Unit) -> Unit)?, b: (() -> Unit)?) =
-    if (<!EQUALITY_NOT_APPLICABLE!>a !== null is Boolean<!> && <!EQUALITY_NOT_APPLICABLE!>b !== null !is Boolean<!>) {
+    if (<!EQUALITY_NOT_APPLICABLE!>a !== <!USELESS_IS_CHECK!>null is Boolean<!><!> && <!EQUALITY_NOT_APPLICABLE!>b !== <!USELESS_IS_CHECK!>null !is Boolean<!><!>) {
         <!UNSAFE_IMPLICIT_INVOKE_CALL!>a<!>(<!DEBUG_INFO_EXPRESSION_TYPE("(() -> kotlin.Unit)?"), TYPE_MISMATCH!>b<!>)
         <!UNSAFE_IMPLICIT_INVOKE_CALL!>a<!>(<!TYPE_MISMATCH!>b<!>)
         <!DEBUG_INFO_EXPRESSION_TYPE("(() -> kotlin.Unit)?")!>b<!><!UNSAFE_CALL!>.<!>equals(null)
@@ -481,4 +481,4 @@ fun case_27() {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number?")!>Object.prop_1<!>.funNullableT()
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Number?")!>Object.prop_1<!>.funNullableAny()
     }
-}
\ No newline at end of file
+}
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/2.kt b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/2.kt
index 0017710c915..3f1990b5596 100644
--- a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/2.kt
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/2.kt
@@ -12,7 +12,7 @@
 
 // TESTCASE NUMBER: 1
 fun case_1(x: Any?) {
-    if (x is Nothing) {
+    if (<!USELESS_IS_CHECK!>x is Nothing<!>) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Any? & kotlin.Nothing")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Nothing"), DEBUG_INFO_SMARTCAST!>x<!>.<!UNREACHABLE_CODE!><!MISSING_DEPENDENCY_CLASS!>inv<!>()<!>
     }
@@ -20,7 +20,7 @@ fun case_1(x: Any?) {
 
 // TESTCASE NUMBER: 2
 fun case_2(x: Any) {
-    if (x is Nothing) {
+    if (<!USELESS_IS_CHECK!>x is Nothing<!>) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Nothing")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Nothing"), DEBUG_INFO_SMARTCAST!>x<!>.<!UNREACHABLE_CODE!><!MISSING_DEPENDENCY_CLASS!>inv<!>()<!>
     }
@@ -28,7 +28,7 @@ fun case_2(x: Any) {
 
 // TESTCASE NUMBER: 3
 fun case_3(x: Any?) {
-    if (x !is Nothing) else {
+    if (<!USELESS_IS_CHECK!>x !is Nothing<!>) else {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Any? & kotlin.Nothing")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Nothing"), DEBUG_INFO_SMARTCAST!>x<!>.<!UNREACHABLE_CODE!><!MISSING_DEPENDENCY_CLASS!>inv<!>()<!>
     }
@@ -36,7 +36,7 @@ fun case_3(x: Any?) {
 
 // TESTCASE NUMBER: 4
 fun case_4(x: Any) {
-    if (x !is Nothing) else {
+    if (<!USELESS_IS_CHECK!>x !is Nothing<!>) else {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Nothing")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Nothing"), DEBUG_INFO_SMARTCAST!>x<!>.<!UNREACHABLE_CODE!><!MISSING_DEPENDENCY_CLASS!>inv<!>()<!>
     }
@@ -52,7 +52,7 @@ fun case_5(x: Any?) {
 
 // TESTCASE NUMBER: 6
 fun case_6(x: Any?) {
-    if (!(x !is Nothing)) {
+    if (!(<!USELESS_IS_CHECK!>x !is Nothing<!>)) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Any? & kotlin.Nothing")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Nothing"), DEBUG_INFO_SMARTCAST!>x<!>.<!UNREACHABLE_CODE!><!MISSING_DEPENDENCY_CLASS!>inv<!>()<!>
     }
@@ -60,7 +60,7 @@ fun case_6(x: Any?) {
 
 // TESTCASE NUMBER: 7
 fun case_7(x: Any) {
-    if (!(x is Nothing)) else {
+    if (!(<!USELESS_IS_CHECK!>x is Nothing<!>)) else {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Nothing")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Nothing"), DEBUG_INFO_SMARTCAST!>x<!>.<!UNREACHABLE_CODE!><!MISSING_DEPENDENCY_CLASS!>inv<!>()<!>
     }
@@ -84,7 +84,7 @@ fun case_9(x: Any?) {
 
 // TESTCASE NUMBER: 10
 fun case_10(x: Any?) {
-    if (!!(x !is Nothing)) else {
+    if (!!(<!USELESS_IS_CHECK!>x !is Nothing<!>)) else {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any & kotlin.Any? & kotlin.Nothing")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Nothing"), DEBUG_INFO_SMARTCAST!>x<!>.<!UNREACHABLE_CODE!><!MISSING_DEPENDENCY_CLASS!>inv<!>()<!>
     }
@@ -96,4 +96,4 @@ fun case_11(x: Any?) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Nothing?")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Nothing?")!>x<!>?.<!MISSING_DEPENDENCY_CLASS!>inv<!>()
     }
-}
\ No newline at end of file
+}
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/3.kt b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/3.kt
index 1dd67eb6210..1385b21a2ae 100644
--- a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/3.kt
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/neg/3.kt
@@ -13,7 +13,7 @@
 
 // TESTCASE NUMBER: 1
 fun case_1(x: Nothing?) {
-    if (<!DEBUG_INFO_CONSTANT!>x<!> is Int) {
+    if (<!USELESS_IS_CHECK!><!DEBUG_INFO_CONSTANT!>x<!> is Int<!>) {
         <!DEBUG_INFO_CONSTANT, DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing?")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing?"), SMARTCAST_IMPOSSIBLE!>x<!>.inv()
     }
@@ -29,7 +29,7 @@ fun case_2(x: Nothing) {
 
 // TESTCASE NUMBER: 3
 fun case_3(x: Nothing?) {
-    if (<!DEBUG_INFO_CONSTANT!>x<!> !is Class) else {
+    if (<!USELESS_IS_CHECK!><!DEBUG_INFO_CONSTANT!>x<!> !is Class<!>) else {
         <!DEBUG_INFO_CONSTANT, DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing?")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing?"), SMARTCAST_IMPOSSIBLE!>x<!>.prop_1
     }
@@ -53,7 +53,7 @@ fun case_5(x: Nothing?) {
 
 // TESTCASE NUMBER: 6
 fun case_6(x: Nothing?) {
-    if (!(<!DEBUG_INFO_CONSTANT!>x<!> !is Object)) {
+    if (!(<!USELESS_IS_CHECK!><!DEBUG_INFO_CONSTANT!>x<!> !is Object<!>)) {
         <!DEBUG_INFO_CONSTANT, DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing?")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing?"), SMARTCAST_IMPOSSIBLE!>x<!>.prop_1
     }
@@ -85,7 +85,7 @@ fun case_9(x: Nothing?) {
 
 // TESTCASE NUMBER: 10
 fun case_10(x: Nothing?) {
-    if (!!(<!DEBUG_INFO_CONSTANT!>x<!> !is Interface3)) else {
+    if (!!(<!USELESS_IS_CHECK!><!DEBUG_INFO_CONSTANT!>x<!> !is Interface3<!>)) else {
         <!DEBUG_INFO_CONSTANT, DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing?")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing?"), SMARTCAST_IMPOSSIBLE!>x<!>.itest()
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Nothing?"), SMARTCAST_IMPOSSIBLE!>x<!>.itest3()
diff --git a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/68.kt b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/68.kt
index a45b4f355bb..58a2a06e10d 100644
--- a/compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/68.kt
+++ b/compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/68.kt
@@ -47,7 +47,7 @@ fun case_4(x: Any?) {
 
 // TESTCASE NUMBER: 5
 fun case_5(x: Any?) {
-    if (x as Nothing? is Nothing) {
+    if (<!USELESS_IS_CHECK!>x as Nothing? is Nothing<!>) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Nothing?")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Nothing?")!>x<!><!UNSAFE_CALL!>.<!><!MISSING_DEPENDENCY_CLASS!>inv<!>()
     }
diff --git a/idea/idea-frontend-fir/idea-fir-low-level-api/tests/org/jetbrains/kotlin/idea/fir/low/level/api/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java b/idea/idea-frontend-fir/idea-fir-low-level-api/tests/org/jetbrains/kotlin/idea/fir/low/level/api/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
index 9044aa6759e..4cfec42c36b 100644
--- a/idea/idea-frontend-fir/idea-fir-low-level-api/tests/org/jetbrains/kotlin/idea/fir/low/level/api/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
+++ b/idea/idea-frontend-fir/idea-fir-low-level-api/tests/org/jetbrains/kotlin/idea/fir/low/level/api/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java
@@ -3609,6 +3609,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 runTest("compiler/testData/diagnostics/tests/cast/FlexibleTargetType.kt");
             }
 
+            @Test
+            @TestMetadata("isAlwaysFalse.kt")
+            public void testIsAlwaysFalse() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/cast/isAlwaysFalse.kt");
+            }
+
             @Test
             @TestMetadata("IsErasedAllowForDerivedWithOneSubstitutedAndOneSameGeneric.kt")
             public void testIsErasedAllowForDerivedWithOneSubstitutedAndOneSameGeneric() throws Exception {