diff --git a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
index 943feeabdd5..3aa57020818 100644
--- a/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
+++ b/compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java
@@ -37112,6 +37112,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/when/implicitExhaustiveAndReturn.kt");
         }
 
+        @Test
+        @TestMetadata("inferredTypeParameters.kt")
+        public void testInferredTypeParameters() throws Exception {
+            runTest("compiler/testData/codegen/box/when/inferredTypeParameters.kt");
+        }
+
         @Test
         @TestMetadata("integralWhenWithNoInlinedConstants.kt")
         public void testIntegralWhenWithNoInlinedConstants() throws Exception {
diff --git a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
index 975966d07ab..1933753b53d 100644
--- a/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
+++ b/compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/diagnostics/FirErrors.kt
@@ -126,7 +126,7 @@ object FirErrors {
     val PROJECTION_ON_NON_CLASS_TYPE_ARGUMENT by error0<FirSourceElement, PsiElement>()
     val UPPER_BOUND_VIOLATED by error2<FirSourceElement, PsiElement, FirTypeParameterSymbol, ConeKotlinType>()
     val TYPE_ARGUMENTS_NOT_ALLOWED by error0<FirSourceElement, PsiElement>()
-    val WRONG_NUMBER_OF_TYPE_ARGUMENTS by error2<FirSourceElement, PsiElement, Int, FirRegularClassSymbol>()
+    val WRONG_NUMBER_OF_TYPE_ARGUMENTS by error2<FirSourceElement, PsiElement, Int, FirClassLikeSymbol<*>>()
     val NO_TYPE_FOR_TYPE_PARAMETER by error0<FirSourceElement, PsiElement>()
     val TYPE_PARAMETERS_IN_OBJECT by error0<FirSourceElement, PsiElement>()
     val ILLEGAL_PROJECTION_USAGE by error0<FirSourceElement, PsiElement>()
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/diagnostics/FirDiagnostics.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/diagnostics/FirDiagnostics.kt
index 209f3c17e30..e50a0be8f76 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/diagnostics/FirDiagnostics.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/diagnostics/FirDiagnostics.kt
@@ -74,7 +74,7 @@ class ConeIllegalAnnotationError(val name: Name) : ConeDiagnostic() {
     override val reason: String get() = "Not a legal annotation: $name"
 }
 
-class ConeWrongNumberOfTypeArgumentsError(val desiredCount: Int, val type: FirRegularClassSymbol) : ConeDiagnostic() {
+class ConeWrongNumberOfTypeArgumentsError(val desiredCount: Int, val type: FirClassLikeSymbol<*>) : ConeDiagnostic() {
     override val reason: String get() = "Wrong number of type arguments"
 }
 
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt
index 62c48e0ceb6..0f18e0da2d8 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirExpressionsResolveTransformer.kt
@@ -450,30 +450,53 @@ open class FirExpressionsResolveTransformer(transformer: FirBodyResolveTransform
         override fun <T> shouldRunCompletion(call: T): Boolean where T : FirStatement, T : FirResolvable = false
     }
 
-    private fun FirTypeRef.withTypeArgumentsForBareType(argument: FirExpression): FirTypeRef {
-        // TODO: Everything should also work for case of checked-type itself is a type alias
-        val type = coneTypeSafe<ConeKotlinType>()
-        if (type !is ConeClassLikeType || type.typeArguments.isNotEmpty()) {
-            return this
+    private fun ConeClassLikeType.inheritTypeArguments(
+        base: FirClassLikeDeclaration<*>,
+        arguments: Array<out ConeTypeProjection>
+    ): Array<out ConeTypeProjection>? {
+        val firClass = lookupTag.toSymbol(session)?.fir ?: return null
+        if (firClass !is FirTypeParameterRefsOwner || firClass.typeParameters.isEmpty()) return arrayOf()
+        return when (firClass) {
+            base -> arguments
+            is FirTypeAlias -> firClass.inheritTypeArguments(firClass.expandedTypeRef, base, arguments)
+            // TODO: if many supertypes, check consistency
+            is FirClass<*> -> firClass.superTypeRefs.mapNotNull { firClass.inheritTypeArguments(it, base, arguments) }.firstOrNull()
+            else -> null
         }
-        val baseTypeArguments =
-            argument.typeRef.coneTypeSafe<ConeKotlinType>()?.fullyExpandedType(session)?.typeArguments
+    }
 
-        return if (baseTypeArguments?.isEmpty() != false) {
-            this
-        } else {
-            val typeParameters = (type.lookupTag.toSymbol(session)?.fir as? FirTypeParameterRefsOwner)?.typeParameters.orEmpty()
-            if (typeParameters.isEmpty()) {
-                this
-            } else {
-                withReplacedConeType(
-                    type.withArguments(
-                        if (baseTypeArguments.size > typeParameters.size) baseTypeArguments.take(typeParameters.size).toTypedArray()
-                        else baseTypeArguments
-                    )
-                )
-            }
+    private fun FirTypeParameterRefsOwner.inheritTypeArguments(
+        typeRef: FirTypeRef,
+        base: FirClassLikeDeclaration<*>,
+        arguments: Array<out ConeTypeProjection>
+    ): Array<out ConeTypeProjection>? {
+        val type = typeRef.coneTypeSafe<ConeClassLikeType>() ?: return null
+        val indexMapping = typeParameters.map { parameter ->
+            // TODO: if many, check consistency of the result
+            type.typeArguments.indexOfFirst { it is ConeTypeParameterType && it.lookupTag.typeParameterSymbol == parameter.symbol }
         }
+        if (indexMapping.any { it == -1 }) return null
+
+        val typeArguments = type.inheritTypeArguments(base, arguments) ?: return null
+        return Array(typeParameters.size) { typeArguments[indexMapping[it]] }
+    }
+
+    private fun FirTypeRef.withTypeArgumentsForBareType(argument: FirExpression): FirTypeRef {
+        val type = coneTypeSafe<ConeClassLikeType>() ?: return this
+        if (type.typeArguments.isNotEmpty()) return this
+
+        val firClass = type.lookupTag.toSymbol(session)?.fir ?: return this
+        if (firClass !is FirTypeParameterRefsOwner || firClass.typeParameters.isEmpty()) return this
+
+        val baseType = argument.typeRef.coneTypeSafe<ConeClassLikeType>()?.fullyExpandedType(session) ?: return this
+        val baseFirClass = baseType.lookupTag.toSymbol(session)?.fir ?: return this
+
+        val newArguments = type.inheritTypeArguments(baseFirClass, baseType.typeArguments)
+            ?: return buildErrorTypeRef {
+                source = this@withTypeArgumentsForBareType.source
+                diagnostic = ConeWrongNumberOfTypeArgumentsError(firClass.typeParameters.size, firClass.symbol)
+            }
+        return if (newArguments.isEmpty()) this else withReplacedConeType(type.withArguments(newArguments))
     }
 
     override fun transformTypeOperatorCall(
diff --git a/compiler/testData/codegen/box/when/inferredTypeParameters.kt b/compiler/testData/codegen/box/when/inferredTypeParameters.kt
new file mode 100644
index 00000000000..fec494e1e70
--- /dev/null
+++ b/compiler/testData/codegen/box/when/inferredTypeParameters.kt
@@ -0,0 +1,19 @@
+sealed class C<out T, out U>
+class A<out T>(val x: T) : C<T, Nothing>()
+class B<out U>(val x: U) : C<Nothing, U>()
+
+fun bar(x: String): C<Int, String> = B(x)
+fun baz(x: Any) = "fail: $x"
+fun baz(x: String) = x
+
+typealias Z<U> = B<U>
+
+fun box(): String =
+    when (val x = bar("O")) {
+        is A -> "fail??"
+        is B -> baz(x.x)
+    } + when (val y = bar("K")) {
+        is A -> "fail??"
+        is Z -> baz(y.x)
+        else -> "..."
+    }
diff --git a/compiler/testData/diagnostics/tests/cast/bare/AsNullableNotEnough.fir.kt b/compiler/testData/diagnostics/tests/cast/bare/AsNullableNotEnough.fir.kt
index 1b46e9c5cdc..b3c7ce638eb 100644
--- a/compiler/testData/diagnostics/tests/cast/bare/AsNullableNotEnough.fir.kt
+++ b/compiler/testData/diagnostics/tests/cast/bare/AsNullableNotEnough.fir.kt
@@ -4,7 +4,7 @@ interface Tr
 interface G<T>
 
 fun test(tr: Tr) {
-    val v = tr as G?
+    val v = tr as <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>G?<!>
     // If v is not nullable, there will be a warning on this line:
-    checkSubtype<G<*>>(v!!)
+    <!INAPPLICABLE_CANDIDATE!>checkSubtype<!><G<*>>(v!!)
 }
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/cast/bare/EitherAs.fir.kt b/compiler/testData/diagnostics/tests/cast/bare/EitherAs.fir.kt
deleted file mode 100644
index 826e39357e0..00000000000
--- a/compiler/testData/diagnostics/tests/cast/bare/EitherAs.fir.kt
+++ /dev/null
@@ -1,18 +0,0 @@
-// !CHECK_TYPE
-
-interface Either<out A, out B>
-interface Left<out A>: Either<A, Nothing>
-interface Right<out B>: Either<Nothing, B>
-
-class C1(val v1: Int)
-class C2(val v2: Int)
-
-fun _as_left(e: Either<C1, C2>): Any {
-    val v = e as Left
-    return checkSubtype<Left<C1>>(v)
-}
-
-fun _as_right(e: Either<C1, C2>): Any {
-    val v = e as Right
-    return <!INAPPLICABLE_CANDIDATE!>checkSubtype<!><Right<C2>>(v)
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/cast/bare/EitherAs.kt b/compiler/testData/diagnostics/tests/cast/bare/EitherAs.kt
index d3c22b7fa60..22af4925558 100644
--- a/compiler/testData/diagnostics/tests/cast/bare/EitherAs.kt
+++ b/compiler/testData/diagnostics/tests/cast/bare/EitherAs.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !CHECK_TYPE
 
 interface Either<out A, out B>
diff --git a/compiler/testData/diagnostics/tests/cast/bare/EitherIs.fir.kt b/compiler/testData/diagnostics/tests/cast/bare/EitherIs.fir.kt
deleted file mode 100644
index 8c93645181b..00000000000
--- a/compiler/testData/diagnostics/tests/cast/bare/EitherIs.fir.kt
+++ /dev/null
@@ -1,25 +0,0 @@
-// !DIAGNOSTICS: -DEBUG_INFO_SMARTCAST
-interface Either<out A, out B>
-interface Left<out A>: Either<A, Nothing> {
-    val value: A
-}
-interface Right<out B>: Either<Nothing, B> {
-    val value: B
-}
-
-class C1(val v1: Int)
-class C2(val v2: Int)
-
-fun _is_l(e: Either<C1, C2>): Any {
-    if (e is Left) {
-        return e.value.v1
-    }
-    return e
-}
-
-fun _is_r(e: Either<C1, C2>): Any {
-    if (e is Right) {
-        return e.value.<!UNRESOLVED_REFERENCE!>v2<!>
-    }
-    return e
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/cast/bare/EitherIs.kt b/compiler/testData/diagnostics/tests/cast/bare/EitherIs.kt
index 29725127b34..8102d393d0b 100644
--- a/compiler/testData/diagnostics/tests/cast/bare/EitherIs.kt
+++ b/compiler/testData/diagnostics/tests/cast/bare/EitherIs.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -DEBUG_INFO_SMARTCAST
 interface Either<out A, out B>
 interface Left<out A>: Either<A, Nothing> {
diff --git a/compiler/testData/diagnostics/tests/cast/bare/EitherNotIs.fir.kt b/compiler/testData/diagnostics/tests/cast/bare/EitherNotIs.fir.kt
deleted file mode 100644
index 3f83e6c0e18..00000000000
--- a/compiler/testData/diagnostics/tests/cast/bare/EitherNotIs.fir.kt
+++ /dev/null
@@ -1,25 +0,0 @@
-// !DIAGNOSTICS: -DEBUG_INFO_SMARTCAST
-interface Either<out A, out B>
-interface Left<out A>: Either<A, Nothing> {
-    val value: A
-}
-interface Right<out B>: Either<Nothing, B> {
-    val value: B
-}
-
-class C1(val v1: Int)
-class C2(val v2: Int)
-
-fun _is_l(e: Either<C1, C2>): Any {
-    if (e !is Left) {
-        return e
-    }
-    return e.value.v1
-}
-
-fun _is_r(e: Either<C1, C2>): Any {
-    if (e !is Right) {
-        return e
-    }
-    return e.value.<!UNRESOLVED_REFERENCE!>v2<!>
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/cast/bare/EitherNotIs.kt b/compiler/testData/diagnostics/tests/cast/bare/EitherNotIs.kt
index a07e46eb9c3..9753a462ea6 100644
--- a/compiler/testData/diagnostics/tests/cast/bare/EitherNotIs.kt
+++ b/compiler/testData/diagnostics/tests/cast/bare/EitherNotIs.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -DEBUG_INFO_SMARTCAST
 interface Either<out A, out B>
 interface Left<out A>: Either<A, Nothing> {
diff --git a/compiler/testData/diagnostics/tests/cast/bare/EitherSafeAs.fir.kt b/compiler/testData/diagnostics/tests/cast/bare/EitherSafeAs.fir.kt
deleted file mode 100644
index 8a1a2e70014..00000000000
--- a/compiler/testData/diagnostics/tests/cast/bare/EitherSafeAs.fir.kt
+++ /dev/null
@@ -1,18 +0,0 @@
-// !CHECK_TYPE
-
-interface Either<out A, out B>
-interface Left<out A>: Either<A, Nothing>
-interface Right<out B>: Either<Nothing, B>
-
-class C1(val v1: Int)
-class C2(val v2: Int)
-
-fun _as_left(e: Either<C1, C2>): Any? {
-    val v = e as? Left
-    return checkSubtype<Left<C1>?>(v)
-}
-
-fun _as_right(e: Either<C1, C2>): Any? {
-    val v = e as? Right
-    return <!INAPPLICABLE_CANDIDATE!>checkSubtype<!><Right<C2>?>(v)
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/cast/bare/EitherSafeAs.kt b/compiler/testData/diagnostics/tests/cast/bare/EitherSafeAs.kt
index ff8660f2698..38421fee7e6 100644
--- a/compiler/testData/diagnostics/tests/cast/bare/EitherSafeAs.kt
+++ b/compiler/testData/diagnostics/tests/cast/bare/EitherSafeAs.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !CHECK_TYPE
 
 interface Either<out A, out B>
diff --git a/compiler/testData/diagnostics/tests/cast/bare/EitherWhen.fir.kt b/compiler/testData/diagnostics/tests/cast/bare/EitherWhen.fir.kt
deleted file mode 100644
index cc6bbd8915a..00000000000
--- a/compiler/testData/diagnostics/tests/cast/bare/EitherWhen.fir.kt
+++ /dev/null
@@ -1,19 +0,0 @@
-// !DIAGNOSTICS: -DEBUG_INFO_SMARTCAST
-interface Either<out A, out B>
-interface Left<out A>: Either<A, Nothing> {
-    val value: A
-}
-interface Right<out B>: Either<Nothing, B> {
-    val value: B
-}
-
-class C1(val v1: Int)
-class C2(val v2: Int)
-
-fun _when(e: Either<C1, C2>): Any {
-    return when (e) {
-        is Left -> e.value.v1
-        is Right -> e.value.<!UNRESOLVED_REFERENCE!>v2<!>
-        else -> e
-    }
-}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/cast/bare/EitherWhen.kt b/compiler/testData/diagnostics/tests/cast/bare/EitherWhen.kt
index ca683c6efda..c83fa5057b3 100644
--- a/compiler/testData/diagnostics/tests/cast/bare/EitherWhen.kt
+++ b/compiler/testData/diagnostics/tests/cast/bare/EitherWhen.kt
@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -DEBUG_INFO_SMARTCAST
 interface Either<out A, out B>
 interface Left<out A>: Either<A, Nothing> {
diff --git a/compiler/testData/diagnostics/tests/cast/bare/NullableAsNotEnough.fir.kt b/compiler/testData/diagnostics/tests/cast/bare/NullableAsNotEnough.fir.kt
index e1509febc32..f85d147fc34 100644
--- a/compiler/testData/diagnostics/tests/cast/bare/NullableAsNotEnough.fir.kt
+++ b/compiler/testData/diagnostics/tests/cast/bare/NullableAsNotEnough.fir.kt
@@ -4,6 +4,6 @@ interface Tr
 interface G<T>
 
 fun test(tr: Tr?) {
-    val v = tr as G
-    checkSubtype<G<*>>(v)
+    val v = tr as <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>G<!>
+    <!INAPPLICABLE_CANDIDATE!>checkSubtype<!><G<*>>(v)
 }
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/cast/bare/NullableAsNullableNotEnough.fir.kt b/compiler/testData/diagnostics/tests/cast/bare/NullableAsNullableNotEnough.fir.kt
index 7fa8d3c395e..d9f5de77af8 100644
--- a/compiler/testData/diagnostics/tests/cast/bare/NullableAsNullableNotEnough.fir.kt
+++ b/compiler/testData/diagnostics/tests/cast/bare/NullableAsNullableNotEnough.fir.kt
@@ -4,6 +4,6 @@ interface Tr
 interface G<T>
 
 fun test(tr: Tr?) {
-    val v = tr as G?
-    checkSubtype<G<*>>(v!!)
+    val v = tr as <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>G?<!>
+    <!INAPPLICABLE_CANDIDATE!>checkSubtype<!><G<*>>(v!!)
 }
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/cast/bare/UnrelatedAs.fir.kt b/compiler/testData/diagnostics/tests/cast/bare/UnrelatedAs.fir.kt
index 3c480012ddb..99ae494e82b 100644
--- a/compiler/testData/diagnostics/tests/cast/bare/UnrelatedAs.fir.kt
+++ b/compiler/testData/diagnostics/tests/cast/bare/UnrelatedAs.fir.kt
@@ -4,6 +4,6 @@ interface Tr
 interface G<T>
 
 fun test(tr: Tr) {
-    val v = tr as G
-    checkSubtype<G<*>>(v)
+    val v = tr as <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>G<!>
+    <!INAPPLICABLE_CANDIDATE!>checkSubtype<!><G<*>>(v)
 }
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/cast/bare/UnrelatedIs.fir.kt b/compiler/testData/diagnostics/tests/cast/bare/UnrelatedIs.fir.kt
index 31a82acc515..8d2b861fab7 100644
--- a/compiler/testData/diagnostics/tests/cast/bare/UnrelatedIs.fir.kt
+++ b/compiler/testData/diagnostics/tests/cast/bare/UnrelatedIs.fir.kt
@@ -1,4 +1,4 @@
 interface Tr
 interface G<T>
 
-fun test(tr: Tr) = tr is G
\ No newline at end of file
+fun test(tr: Tr) = tr is <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>G<!>
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/generics/RawTypeInIsExpression.fir.kt b/compiler/testData/diagnostics/tests/generics/RawTypeInIsExpression.fir.kt
index e106601f1e6..dd9049258b6 100644
--- a/compiler/testData/diagnostics/tests/generics/RawTypeInIsExpression.fir.kt
+++ b/compiler/testData/diagnostics/tests/generics/RawTypeInIsExpression.fir.kt
@@ -2,13 +2,13 @@ package p
 
 public fun foo(a: Any) {
     a is Map<Int>
-    a is Map
+    a is <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>Map<!>
     a is Map<out Any?, Any?>
     a is Map<*, *>
     a is Map<<!SYNTAX!><!>>
     a is List<Map>
-    a is List
+    a is <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>List<!>
     a is Int
 
-    (a as Map) is Int
+    (a as <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>Map<!>) is Int
 }
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/generics/RawTypeInIsPattern.fir.kt b/compiler/testData/diagnostics/tests/generics/RawTypeInIsPattern.fir.kt
index f76110a228e..bfca3e37219 100644
--- a/compiler/testData/diagnostics/tests/generics/RawTypeInIsPattern.fir.kt
+++ b/compiler/testData/diagnostics/tests/generics/RawTypeInIsPattern.fir.kt
@@ -1,12 +1,12 @@
 public fun foo(a: Any, b: Map) {
     when (a) {
         is Map<Int> -> {}
-        is Map -> {}
+        is <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>Map<!> -> {}
         is Map<out Any?, Any?> -> {}
         is Map<*, *> -> {}
         is Map<<!SYNTAX!><!>> -> {}
         is List<Map> -> {}
-        is List -> {}
+        is <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>List<!> -> {}
         is Int -> {}
         else -> {}
     }
diff --git a/compiler/testData/diagnostics/tests/generics/innerClasses/bareTypesComplex.fir.kt b/compiler/testData/diagnostics/tests/generics/innerClasses/bareTypesComplex.fir.kt
index 0bb4850fb9f..7eaeb08a95e 100644
--- a/compiler/testData/diagnostics/tests/generics/innerClasses/bareTypesComplex.fir.kt
+++ b/compiler/testData/diagnostics/tests/generics/innerClasses/bareTypesComplex.fir.kt
@@ -8,7 +8,7 @@ class DerivedOuter<G> : SuperOuter<G>() {
 
 fun bare(x: SuperOuter<*>.SuperInner<*>, y: Any?) {
     if (x is SuperOuter.SuperInner) return
-    if (y is SuperOuter.SuperInner) {
+    if (y is <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>SuperOuter.SuperInner<!>) {
         return
     }
 }
diff --git a/compiler/testData/diagnostics/tests/generics/innerClasses/innerUncheckedCast.fir.kt b/compiler/testData/diagnostics/tests/generics/innerClasses/innerUncheckedCast.fir.kt
index bd5a5ec222e..6b1e7bd1725 100644
--- a/compiler/testData/diagnostics/tests/generics/innerClasses/innerUncheckedCast.fir.kt
+++ b/compiler/testData/diagnostics/tests/generics/innerClasses/innerUncheckedCast.fir.kt
@@ -12,7 +12,7 @@ class Outer<E> {
             x.prop.checkType { _<E>() }
         }
 
-        if (y is Inner) return
+        if (y is <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>Inner<!>) return
 
         if (z is Inner) {
             z.prop.checkType { _<Any?>() }
@@ -26,7 +26,7 @@ class Outer<E> {
 
     fun bar(x: InnerBase<String>, y: Any?, z: Outer<*>.InnerBase<String>) {
         x as Inner
-        y as Inner
+        y as <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>Inner<!>
         z as Inner
     }
 }
diff --git a/compiler/testData/diagnostics/tests/typealias/typeAliasAsBareType.fir.kt b/compiler/testData/diagnostics/tests/typealias/typeAliasAsBareType.fir.kt
index 5c58097d79b..b375a2a8c49 100644
--- a/compiler/testData/diagnostics/tests/typealias/typeAliasAsBareType.fir.kt
+++ b/compiler/testData/diagnostics/tests/typealias/typeAliasAsBareType.fir.kt
@@ -14,8 +14,8 @@ fun testNL1(x: Collection<Int>?): Boolean = x is NL
 fun testNL2(x: Collection<Int>?): List<Int>? = x as NL
 fun testNL3(x: Collection<Int>?): List<Int>? = x as NL?
 
-fun testLStar(x: Collection<Int>): List<Int> = x as LStar
-fun testMyList(x: Collection<Int>): List<Int> = x as MyList
+fun testLStar(x: Collection<Int>): List<Int> = x as <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>LStar<!>
+fun testMyList(x: Collection<Int>): List<Int> = x as <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>MyList<!>
 
 typealias MMTT<T> = MutableMap<T, T>
 typealias Dictionary<T> = MutableMap<String, T>
@@ -24,8 +24,8 @@ typealias ReadableList<T> = MutableList<out T>
 
 fun testWrong1(x: Map<Any, Any>) = x is MMTT
 fun testWrong2(x: Map<Any, Any>) = x is Dictionary
-fun testWrong3(x: Map<Any, Any>) = x is WriteableMap
-fun testWrong4(x: List<Any>) = x is ReadableList
+fun testWrong3(x: Map<Any, Any>) = x is <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>WriteableMap<!>
+fun testWrong4(x: List<Any>) = x is <!WRONG_NUMBER_OF_TYPE_ARGUMENTS!>ReadableList<!>
 
 fun <T> testLocal(x: Any) {
     class C
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
index bb729d71633..160aeb4416c 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/BlackBoxCodegenTestGenerated.java
@@ -37312,6 +37312,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/when/implicitExhaustiveAndReturn.kt");
         }
 
+        @Test
+        @TestMetadata("inferredTypeParameters.kt")
+        public void testInferredTypeParameters() throws Exception {
+            runTest("compiler/testData/codegen/box/when/inferredTypeParameters.kt");
+        }
+
         @Test
         @TestMetadata("integralWhenWithNoInlinedConstants.kt")
         public void testIntegralWhenWithNoInlinedConstants() throws Exception {
diff --git a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
index 22a5574719e..021080dbbd3 100644
--- a/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
+++ b/compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java
@@ -37112,6 +37112,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/when/implicitExhaustiveAndReturn.kt");
         }
 
+        @Test
+        @TestMetadata("inferredTypeParameters.kt")
+        public void testInferredTypeParameters() throws Exception {
+            runTest("compiler/testData/codegen/box/when/inferredTypeParameters.kt");
+        }
+
         @Test
         @TestMetadata("integralWhenWithNoInlinedConstants.kt")
         public void testIntegralWhenWithNoInlinedConstants() throws Exception {
diff --git a/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java b/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
index a6bad3af3a6..40c0c116ed4 100644
--- a/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
+++ b/compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
@@ -30617,6 +30617,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/when/implicitExhaustiveAndReturn.kt");
         }
 
+        @TestMetadata("inferredTypeParameters.kt")
+        public void testInferredTypeParameters() throws Exception {
+            runTest("compiler/testData/codegen/box/when/inferredTypeParameters.kt");
+        }
+
         @TestMetadata("integralWhenWithNoInlinedConstants.kt")
         public void testIntegralWhenWithNoInlinedConstants() throws Exception {
             runTest("compiler/testData/codegen/box/when/integralWhenWithNoInlinedConstants.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
index a878893ba18..18325dc6390 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
@@ -26438,6 +26438,11 @@ public class IrJsCodegenBoxES6TestGenerated extends AbstractIrJsCodegenBoxES6Tes
             runTest("compiler/testData/codegen/box/when/implicitExhaustiveAndReturn.kt");
         }
 
+        @TestMetadata("inferredTypeParameters.kt")
+        public void testInferredTypeParameters() throws Exception {
+            runTest("compiler/testData/codegen/box/when/inferredTypeParameters.kt");
+        }
+
         @TestMetadata("integralWhenWithNoInlinedConstants.kt")
         public void testIntegralWhenWithNoInlinedConstants() throws Exception {
             runTest("compiler/testData/codegen/box/when/integralWhenWithNoInlinedConstants.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
index 7dfd2fabe16..572014b9ef3 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
@@ -26438,6 +26438,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/when/implicitExhaustiveAndReturn.kt");
         }
 
+        @TestMetadata("inferredTypeParameters.kt")
+        public void testInferredTypeParameters() throws Exception {
+            runTest("compiler/testData/codegen/box/when/inferredTypeParameters.kt");
+        }
+
         @TestMetadata("integralWhenWithNoInlinedConstants.kt")
         public void testIntegralWhenWithNoInlinedConstants() throws Exception {
             runTest("compiler/testData/codegen/box/when/integralWhenWithNoInlinedConstants.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
index f3fd0c1d277..dc44e0a72dc 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
@@ -26403,6 +26403,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/when/implicitExhaustiveAndReturn.kt");
         }
 
+        @TestMetadata("inferredTypeParameters.kt")
+        public void testInferredTypeParameters() throws Exception {
+            runTest("compiler/testData/codegen/box/when/inferredTypeParameters.kt");
+        }
+
         @TestMetadata("integralWhenWithNoInlinedConstants.kt")
         public void testIntegralWhenWithNoInlinedConstants() throws Exception {
             runTest("compiler/testData/codegen/box/when/integralWhenWithNoInlinedConstants.kt");
diff --git a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
index 13221bc458a..90ae451e0a9 100644
--- a/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
+++ b/js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java
@@ -14599,6 +14599,11 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
             runTest("compiler/testData/codegen/box/when/implicitExhaustiveAndReturn.kt");
         }
 
+        @TestMetadata("inferredTypeParameters.kt")
+        public void testInferredTypeParameters() throws Exception {
+            runTest("compiler/testData/codegen/box/when/inferredTypeParameters.kt");
+        }
+
         @TestMetadata("kt2457.kt")
         public void testKt2457() throws Exception {
             runTest("compiler/testData/codegen/box/when/kt2457.kt");