diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ClassReferenceLowering.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ClassReferenceLowering.kt
index 1e8510e7f16..1d587353f2a 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ClassReferenceLowering.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ClassReferenceLowering.kt
@@ -135,7 +135,7 @@ class ClassReferenceLowering(val context: JsIrBackendContext) : FileLoweringPass
             override fun visitClassReference(expression: IrClassReference) =
                 callGetKClass(
                     returnType = expression.type,
-                    typeArgument = expression.classType.makeNotNull()
+                    typeArgument = expression.classType.makeNotNull(false)
                 )
         })
     }
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ThrowableSuccessorsLowering.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ThrowableSuccessorsLowering.kt
index 577f612bbcf..987e5b68abd 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ThrowableSuccessorsLowering.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ThrowableSuccessorsLowering.kt
@@ -131,7 +131,7 @@ class ThrowableSuccessorsLowering(val context: JsIrBackendContext) : FileLowerin
                 else -> {
                     val arg = expression.getValueArgument(0)!!
                     when {
-                        arg.type.makeNotNull().isThrowable() -> Pair(nullValue(), arg)
+                        arg.type.makeNotNull(false).isThrowable() -> Pair(nullValue(), arg)
                         else -> Pair(arg, nullValue())
                     }
                 }
@@ -294,7 +294,7 @@ class ThrowableSuccessorsLowering(val context: JsIrBackendContext) : FileLowerin
                     val irVal = JsIrBuilder.buildVar(arg.type, parent, initializer = arg)
                     val argValue = JsIrBuilder.buildGetValue(irVal.symbol)
                     when {
-                        arg.type.makeNotNull().isThrowable() -> Triple(safeCallToString(irVal), argValue, listOf(irVal))
+                        arg.type.makeNotNull(false).isThrowable() -> Triple(safeCallToString(irVal), argValue, listOf(irVal))
                         else -> Triple(argValue, nullValue(), listOf(irVal))
                     }
                 }
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/TypeOperatorLowering.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/TypeOperatorLowering.kt
index 0dea3d84aba..dfe4ef27394 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/TypeOperatorLowering.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/TypeOperatorLowering.kt
@@ -186,7 +186,7 @@ class TypeOperatorLowering(val context: JsIrBackendContext) : FileLoweringPass {
                     }
                 }
 
-                val toNotNullable = toType.makeNotNull()
+                val toNotNullable = toType.makeNotNull(false)
                 val argumentInstance = argument()
                 val instanceCheck = generateTypeCheckNonNull(argumentInstance, toNotNullable)
                 val isFromNullable = argumentInstance.type.isNullable()
@@ -246,7 +246,7 @@ class TypeOperatorLowering(val context: JsIrBackendContext) : FileLoweringPass {
 
                 assert(!typeParameter.isReified) { "reified parameters have to be lowered before" }
                 return typeParameter.superTypes.fold(litTrue) { r, t ->
-                    val check = generateTypeCheckNonNull(argument.copy(), t.makeNotNull())
+                    val check = generateTypeCheckNonNull(argument.copy(), t.makeNotNull(false))
                     calculator.and(r, check)
                 }
             }
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/calls/CallsLoweringUtils.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/calls/CallsLoweringUtils.kt
index efa96b934a7..5c6f76d755a 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/calls/CallsLoweringUtils.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/calls/CallsLoweringUtils.kt
@@ -88,7 +88,7 @@ enum class PrimitiveType {
     OTHER
 }
 
-fun IrType.getPrimitiveType() = makeNotNull().run {
+fun IrType.getPrimitiveType() = makeNotNull(false).run {
     when {
         isBoolean() -> PrimitiveType.BOOLEAN
         isByte() || isShort() || isInt() -> PrimitiveType.INTEGER_NUMBER