[FIR] Add FirCheckNotNullCall converted to CHECK_NOT_NULL intrinsic

function call.

compiler/testData/codegen/box/binaryOp/callNullable.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     val a1: Byte? = 1.plus(1)
     val a2: Short? = 1.plus(1)

compiler/testData/codegen/box/binaryOp/intrinsicNullable.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     val a1: Byte? = 1 + 1
     val a2: Short? = 1 + 1

compiler/testData/codegen/box/classes/kt725.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 operator fun Int?.inc() = this!!.inc()
 
 public fun box() : String {

compiler/testData/codegen/box/controlStructures/kt2147.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 class Foo {
   fun isOk() = true
 }

compiler/testData/codegen/box/controlStructures/kt628.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 class A() {
   fun action() = "OK"
 

compiler/testData/codegen/box/controlStructures/returnsNothing/ifElse.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 var flag = true
 
 fun exit(): Nothing = null!!

compiler/testData/codegen/box/controlStructures/returnsNothing/inlineMethod.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 inline fun exit(): Nothing = null!!
 
 fun box(): String {

compiler/testData/codegen/box/controlStructures/returnsNothing/propertyGetter.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 var flag = true
 
 object Test {

compiler/testData/codegen/box/controlStructures/returnsNothing/tryCatch.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun exit(): Nothing = null!!
 
 fun box(): String {

compiler/testData/codegen/box/controlStructures/returnsNothing/when.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun exit(): Nothing = null!!
 
 var x = 0

compiler/testData/codegen/box/exclExcl/genericNull.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun <T> foo(t: T) {
     t!!
 }

compiler/testData/codegen/box/fullJdk/ifInWhile.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // TARGET_BACKEND: JVM
 
 // FULL_JDK

compiler/testData/codegen/box/ieee754/explicitCompareCall.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun less1(a: Double, b: Double) = a.compareTo(b) == -1
 
 fun less2(a: Double?, b: Double?) = a!!.compareTo(b!!) == -1

compiler/testData/codegen/box/ieee754/explicitEqualsCall.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun equals1(a: Double, b: Double) = a.equals(b)
 
 fun equals2(a: Double?, b: Double?) = a!!.equals(b!!)

compiler/testData/codegen/box/ieee754/greaterDouble_properIeeeComparisons.kt

@@ -1,5 +1,4 @@
 // !LANGUAGE: +ProperIeee754Comparisons
-// IGNORE_BACKEND_FIR: JVM_IR
 
 fun greater1(a: Double, b: Double) = a > b
 

compiler/testData/codegen/box/ieee754/greaterFloat_properIeeeComparisons.kt

@@ -1,5 +1,4 @@
 // !LANGUAGE: +ProperIeee754Comparisons
-// IGNORE_BACKEND_FIR: JVM_IR
 
 fun greater1(a: Float, b: Float) = a > b
 

compiler/testData/codegen/box/ieee754/lessDouble_properIeeeComparisons.kt

@@ -1,5 +1,4 @@
 // !LANGUAGE: +ProperIeee754Comparisons
-// IGNORE_BACKEND_FIR: JVM_IR
 
 fun less1(a: Double, b: Double) = a < b
 

compiler/testData/codegen/box/ieee754/lessFloat_properIeeeComparisons.kt

@@ -1,5 +1,4 @@
 // !LANGUAGE: +ProperIeee754Comparisons
-// IGNORE_BACKEND_FIR: JVM_IR
 
 fun less1(a: Float, b: Float) = a < b
 

compiler/testData/codegen/box/ieee754/safeCall.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     val plusZero: Double? = 0.0
     val minusZero: Double = -0.0

compiler/testData/codegen/box/intrinsics/throwable.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // IGNORE_BACKEND: JS_IR
 // TODO: muted automatically, investigate should it be ran for JS or not
 // IGNORE_BACKEND: JS, NATIVE

compiler/testData/codegen/box/lazyCodegen/optimizations/negateObjectComp.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 val p: Int? = 1;
 val z: Int? = 2;
 

compiler/testData/codegen/box/lazyCodegen/optimizations/negateObjectComp2.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 val p: Int? = 1;
 val z: Int? = 2;
 

compiler/testData/codegen/box/lazyCodegen/safeAssign.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 class Shape(var result: String) {
 
 }

compiler/testData/codegen/box/primitiveTypes/kt3613.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun foo(): Int? = 42
 
 fun box(): String {

compiler/testData/codegen/box/primitiveTypes/kt4098.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     val c: Char? = '0'
     c!!.toInt()

compiler/testData/codegen/box/primitiveTypes/kt4210.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     val s: String? = "abc"
     val c = s?.get(0)!! - 'b'

compiler/testData/codegen/box/primitiveTypes/kt753.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // IGNORE_BACKEND: JS_IR
 // TODO: muted automatically, investigate should it be ran for JS or not
 // IGNORE_BACKEND: JS, NATIVE

compiler/testData/codegen/box/primitiveTypes/kt756.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // IGNORE_BACKEND: JS_IR
 // TODO: muted automatically, investigate should it be ran for JS or not
 // IGNORE_BACKEND: JS, NATIVE

compiler/testData/codegen/box/primitiveTypes/kt757.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 // IGNORE_BACKEND: JS_IR
 // TODO: muted automatically, investigate should it be ran for JS or not
 // IGNORE_BACKEND: JS, NATIVE

compiler/testData/codegen/box/primitiveTypes/nullAsNullableIntIsNull.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     try {
         if ((null as Int?)!! == 10) return "Fail #1"

compiler/testData/codegen/box/primitiveTypes/nullableCharBoolean.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     val c: Char? = 'a'
     if (c!! - 'a' != 0) return "Fail c"

compiler/testData/codegen/box/specialBuiltins/throwable.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     try {
         throw Throwable("OK", null)

compiler/testData/codegen/box/unaryOp/callNullable.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     val a1: Byte? = 1.unaryMinus()
     val a2: Short? = 1.unaryMinus()

compiler/testData/codegen/box/unaryOp/intrinsicNullable.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND_FIR: JVM_IR
 fun box(): String {
     val a1: Byte? = -1
     val a2: Short? = -1

compiler/testData/ir/irText/expressions/bangbang.fir.txt

@@ -3,55 +3,25 @@ FILE fqName:<root> fileName:/bangbang.kt
     VALUE_PARAMETER name:a index:0 type:kotlin.Any?
     BLOCK_BODY
       RETURN type=kotlin.Nothing from='public final fun test1 (a: kotlin.Any?): kotlin.Any declared in <root>'
-        BLOCK type=kotlin.Any origin=EXCLEXCL
-          VAR IR_TEMPORARY_VARIABLE name:tmp_0 type:kotlin.Any? [val]
-            GET_VAR 'a: kotlin.Any? declared in <root>.test1' type=kotlin.Any? origin=null
-          WHEN type=kotlin.Any origin=EXCLEXCL
-            BRANCH
-              if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
-                arg0: GET_VAR 'val tmp_0: kotlin.Any? [val] declared in <root>.test1' type=kotlin.Any? origin=null
-                arg1: CONST Null type=kotlin.Nothing? value=null
-              then: THROW type=kotlin.Nothing
-                ERROR_CALL 'Unresolved reference: <Unresolved name: KotlinNullPointerException>#' type=IrErrorType
-            BRANCH
-              if: CONST Boolean type=kotlin.Boolean value=true
-              then: GET_VAR 'val tmp_0: kotlin.Any? [val] declared in <root>.test1' type=kotlin.Any origin=null
+        CALL 'public final fun CHECK_NOT_NULL <T0> (arg0: T0 of kotlin.internal.ir.CHECK_NOT_NULL?): T0 of kotlin.internal.ir.CHECK_NOT_NULL declared in kotlin.internal.ir' type=kotlin.Any origin=EXCLEXCL
+          <T0>: kotlin.Any
+          arg0: GET_VAR 'a: kotlin.Any? declared in <root>.test1' type=kotlin.Any? origin=null
   FUN name:test2 visibility:public modality:FINAL <> (a:kotlin.Any?) returnType:kotlin.Int
     VALUE_PARAMETER name:a index:0 type:kotlin.Any?
     BLOCK_BODY
       RETURN type=kotlin.Nothing from='public final fun test2 (a: kotlin.Any?): kotlin.Int declared in <root>'
-        BLOCK type=kotlin.Int origin=EXCLEXCL
-          VAR IR_TEMPORARY_VARIABLE name:tmp_1 type:kotlin.Int? [val]
-            CALL 'public open fun hashCode (): kotlin.Int declared in kotlin.Any' type=kotlin.Int? origin=null
-              $this: GET_VAR 'a: kotlin.Any? declared in <root>.test2' type=kotlin.Any? origin=null
-          WHEN type=kotlin.Int origin=EXCLEXCL
-            BRANCH
-              if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
-                arg0: GET_VAR 'val tmp_1: kotlin.Int? [val] declared in <root>.test2' type=kotlin.Int? origin=null
-                arg1: CONST Null type=kotlin.Nothing? value=null
-              then: THROW type=kotlin.Nothing
-                ERROR_CALL 'Unresolved reference: <Unresolved name: KotlinNullPointerException>#' type=IrErrorType
-            BRANCH
-              if: CONST Boolean type=kotlin.Boolean value=true
-              then: GET_VAR 'val tmp_1: kotlin.Int? [val] declared in <root>.test2' type=kotlin.Int origin=null
-  FUN name:test3 visibility:public modality:FINAL <X> (a:X of <root>.test3) returnType:kotlin.Any
+        CALL 'public final fun CHECK_NOT_NULL <T0> (arg0: T0 of kotlin.internal.ir.CHECK_NOT_NULL?): T0 of kotlin.internal.ir.CHECK_NOT_NULL declared in kotlin.internal.ir' type=kotlin.Int origin=EXCLEXCL
+          <T0>: kotlin.Int
+          arg0: CALL 'public open fun hashCode (): kotlin.Int declared in kotlin.Any' type=kotlin.Int? origin=null
+            $this: GET_VAR 'a: kotlin.Any? declared in <root>.test2' type=kotlin.Any? origin=null
+  FUN name:test3 visibility:public modality:FINAL <X> (a:X of <root>.test3) returnType:X of <root>.test3
     TYPE_PARAMETER name:X index:0 variance: superTypes:[kotlin.Any?]
     VALUE_PARAMETER name:a index:0 type:X of <root>.test3
     BLOCK_BODY
-      RETURN type=kotlin.Nothing from='public final fun test3 <X> (a: X of <root>.test3): kotlin.Any declared in <root>'
-        BLOCK type=kotlin.Any origin=EXCLEXCL
-          VAR IR_TEMPORARY_VARIABLE name:tmp_2 type:X of <root>.test3 [val]
-            GET_VAR 'a: X of <root>.test3 declared in <root>.test3' type=X of <root>.test3 origin=null
-          WHEN type=kotlin.Any origin=EXCLEXCL
-            BRANCH
-              if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
-                arg0: GET_VAR 'val tmp_2: X of <root>.test3 [val] declared in <root>.test3' type=X of <root>.test3 origin=null
-                arg1: CONST Null type=kotlin.Nothing? value=null
-              then: THROW type=kotlin.Nothing
-                ERROR_CALL 'Unresolved reference: <Unresolved name: KotlinNullPointerException>#' type=IrErrorType
-            BRANCH
-              if: CONST Boolean type=kotlin.Boolean value=true
-              then: GET_VAR 'val tmp_2: X of <root>.test3 [val] declared in <root>.test3' type=kotlin.Any origin=null
+      RETURN type=kotlin.Nothing from='public final fun test3 <X> (a: X of <root>.test3): X of <root>.test3 declared in <root>'
+        CALL 'public final fun CHECK_NOT_NULL <T0> (arg0: T0 of kotlin.internal.ir.CHECK_NOT_NULL?): T0 of kotlin.internal.ir.CHECK_NOT_NULL declared in kotlin.internal.ir' type=X of <root>.test3 origin=EXCLEXCL
+          <T0>: X of <root>.test3
+          arg0: GET_VAR 'a: X of <root>.test3 declared in <root>.test3' type=X of <root>.test3 origin=null
   FUN name:useString visibility:public modality:FINAL <> (s:kotlin.String) returnType:kotlin.Unit
     VALUE_PARAMETER name:s index:0 type:kotlin.String
     BLOCK_BODY
@@ -63,34 +33,14 @@ FILE fqName:<root> fileName:/bangbang.kt
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=kotlin.String?
             GET_VAR 'a: X of <root>.test4 declared in <root>.test4' type=X of <root>.test4 origin=null
-          then: BLOCK type=kotlin.String origin=EXCLEXCL
-            VAR IR_TEMPORARY_VARIABLE name:tmp_3 type:kotlin.String? [val]
-              GET_VAR 'a: X of <root>.test4 declared in <root>.test4' type=kotlin.String? origin=null
-            WHEN type=kotlin.String origin=EXCLEXCL
-              BRANCH
-                if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
-                  arg0: GET_VAR 'val tmp_3: kotlin.String? [val] declared in <root>.test4' type=kotlin.String? origin=null
-                  arg1: CONST Null type=kotlin.Nothing? value=null
-                then: THROW type=kotlin.Nothing
-                  ERROR_CALL 'Unresolved reference: <Unresolved name: KotlinNullPointerException>#' type=IrErrorType
-              BRANCH
-                if: CONST Boolean type=kotlin.Boolean value=true
-                then: GET_VAR 'val tmp_3: kotlin.String? [val] declared in <root>.test4' type=kotlin.String origin=null
+          then: CALL 'public final fun CHECK_NOT_NULL <T0> (arg0: T0 of kotlin.internal.ir.CHECK_NOT_NULL?): T0 of kotlin.internal.ir.CHECK_NOT_NULL declared in kotlin.internal.ir' type=kotlin.String? origin=EXCLEXCL
+            <T0>: kotlin.String
+            arg0: GET_VAR 'a: X of <root>.test4 declared in <root>.test4' type=kotlin.String? origin=null
       WHEN type=kotlin.Unit origin=IF
         BRANCH
           if: TYPE_OP type=kotlin.Boolean origin=INSTANCEOF typeOperand=kotlin.String?
             GET_VAR 'a: X of <root>.test4 declared in <root>.test4' type=X of <root>.test4 origin=null
           then: CALL 'public final fun useString (s: kotlin.String): kotlin.Unit declared in <root>' type=kotlin.Unit origin=null
-            s: BLOCK type=kotlin.String origin=EXCLEXCL
-              VAR IR_TEMPORARY_VARIABLE name:tmp_4 type:kotlin.String? [val]
-                GET_VAR 'a: X of <root>.test4 declared in <root>.test4' type=kotlin.String? origin=null
-              WHEN type=kotlin.String origin=EXCLEXCL
-                BRANCH
-                  if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
-                    arg0: GET_VAR 'val tmp_4: kotlin.String? [val] declared in <root>.test4' type=kotlin.String? origin=null
-                    arg1: CONST Null type=kotlin.Nothing? value=null
-                  then: THROW type=kotlin.Nothing
-                    ERROR_CALL 'Unresolved reference: <Unresolved name: KotlinNullPointerException>#' type=IrErrorType
-                BRANCH
-                  if: CONST Boolean type=kotlin.Boolean value=true
-                  then: GET_VAR 'val tmp_4: kotlin.String? [val] declared in <root>.test4' type=kotlin.String origin=null
+            s: CALL 'public final fun CHECK_NOT_NULL <T0> (arg0: T0 of kotlin.internal.ir.CHECK_NOT_NULL?): T0 of kotlin.internal.ir.CHECK_NOT_NULL declared in kotlin.internal.ir' type=kotlin.String? origin=EXCLEXCL
+              <T0>: kotlin.String
+              arg0: GET_VAR 'a: X of <root>.test4 declared in <root>.test4' type=kotlin.String? origin=null

compiler/testData/ir/irText/expressions/floatingPointComparisons/eqeqRhsConditionPossiblyAffectingLhs.fir.txt

@@ -9,19 +9,9 @@ FILE fqName:<root> fileName:/eqeqRhsConditionPossiblyAffectingLhs.kt
             BRANCH
               if: TYPE_OP type=kotlin.Boolean origin=NOT_INSTANCEOF typeOperand=kotlin.Double
                 GET_VAR 'x: kotlin.Any declared in <root>.test' type=kotlin.Any origin=null
-              then: BLOCK type=kotlin.Nothing origin=EXCLEXCL
-                VAR IR_TEMPORARY_VARIABLE name:tmp_0 type:kotlin.Nothing? [val]
-                  CONST Null type=kotlin.Nothing? value=null
-                WHEN type=kotlin.Nothing origin=EXCLEXCL
-                  BRANCH
-                    if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
-                      arg0: GET_VAR 'val tmp_0: kotlin.Nothing? [val] declared in <root>.test' type=kotlin.Nothing? origin=null
-                      arg1: CONST Null type=kotlin.Nothing? value=null
-                    then: THROW type=kotlin.Nothing
-                      ERROR_CALL 'Unresolved reference: <Unresolved name: KotlinNullPointerException>#' type=IrErrorType
-                  BRANCH
-                    if: CONST Boolean type=kotlin.Boolean value=true
-                    then: GET_VAR 'val tmp_0: kotlin.Nothing? [val] declared in <root>.test' type=kotlin.Nothing origin=null
+              then: CALL 'public final fun CHECK_NOT_NULL <T0> (arg0: T0 of kotlin.internal.ir.CHECK_NOT_NULL?): T0 of kotlin.internal.ir.CHECK_NOT_NULL declared in kotlin.internal.ir' type=kotlin.Nothing origin=EXCLEXCL
+                <T0>: kotlin.Nothing
+                arg0: CONST Null type=kotlin.Nothing? value=null
             BRANCH
               if: CONST Boolean type=kotlin.Boolean value=true
               then: GET_VAR 'x: kotlin.Any declared in <root>.test' type=kotlin.Double origin=null

compiler/testData/ir/irText/expressions/kt30020.fir.txt

@@ -48,37 +48,17 @@ FILE fqName:<root> fileName:/kt30020.kt
         element: CONST Int type=kotlin.Int value=4
       CALL 'public final fun plusAssign <T> (element: T of kotlin.collections.plusAssign): kotlin.Unit [inline,operator] declared in kotlin.collections' type=kotlin.Unit origin=null
         <T>: kotlin.Int
-        $receiver: BLOCK type=kotlin.collections.MutableList<kotlin.Int> origin=EXCLEXCL
-          VAR IR_TEMPORARY_VARIABLE name:tmp_0 type:kotlin.collections.MutableList<kotlin.Int> [val]
-            CALL 'public abstract fun <get-xs> (): kotlin.collections.MutableList<kotlin.Any> declared in <root>.X' type=kotlin.collections.MutableList<kotlin.Int> origin=null
-              $this: GET_VAR 'nx: <root>.X? declared in <root>.test' type=<root>.X? origin=null
-          WHEN type=kotlin.collections.MutableList<kotlin.Int> origin=EXCLEXCL
-            BRANCH
-              if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
-                arg0: GET_VAR 'val tmp_0: kotlin.collections.MutableList<kotlin.Int> [val] declared in <root>.test' type=kotlin.collections.MutableList<kotlin.Int> origin=null
-                arg1: CONST Null type=kotlin.Nothing? value=null
-              then: THROW type=kotlin.Nothing
-                CONSTRUCTOR_CALL 'public constructor <init> () declared in kotlin.KotlinNullPointerException' type=kotlin.KotlinNullPointerException origin=null
-            BRANCH
-              if: CONST Boolean type=kotlin.Boolean value=true
-              then: GET_VAR 'val tmp_0: kotlin.collections.MutableList<kotlin.Int> [val] declared in <root>.test' type=kotlin.collections.MutableList<kotlin.Int> origin=null
+        $receiver: CALL 'public final fun CHECK_NOT_NULL <T0> (arg0: T0 of kotlin.internal.ir.CHECK_NOT_NULL?): T0 of kotlin.internal.ir.CHECK_NOT_NULL declared in kotlin.internal.ir' type=kotlin.collections.MutableList<kotlin.Int> origin=EXCLEXCL
+          <T0>: kotlin.collections.MutableList<kotlin.Int>
+          arg0: CALL 'public abstract fun <get-xs> (): kotlin.collections.MutableList<kotlin.Any> declared in <root>.X' type=kotlin.collections.MutableList<kotlin.Int> origin=null
+            $this: GET_VAR 'nx: <root>.X? declared in <root>.test' type=<root>.X? origin=null
         element: CONST Int type=kotlin.Int value=5
       CALL 'public final fun plusAssign <T> (element: T of kotlin.collections.plusAssign): kotlin.Unit [inline,operator] declared in kotlin.collections' type=kotlin.Unit origin=null
         <T>: kotlin.Int
-        $receiver: BLOCK type=kotlin.collections.MutableList<kotlin.Int> origin=EXCLEXCL
-          VAR IR_TEMPORARY_VARIABLE name:tmp_1 type:kotlin.collections.MutableList<kotlin.Any>? [val]
-            CALL 'public abstract fun f (): kotlin.collections.MutableList<kotlin.Any> declared in <root>.X' type=kotlin.collections.MutableList<kotlin.Any>? origin=null
-              $this: GET_VAR 'nx: <root>.X? declared in <root>.test' type=<root>.X origin=null
-          WHEN type=kotlin.collections.MutableList<kotlin.Int> origin=EXCLEXCL
-            BRANCH
-              if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
-                arg0: GET_VAR 'val tmp_1: kotlin.collections.MutableList<kotlin.Any>? [val] declared in <root>.test' type=kotlin.collections.MutableList<kotlin.Any>? origin=null
-                arg1: CONST Null type=kotlin.Nothing? value=null
-              then: THROW type=kotlin.Nothing
-                CONSTRUCTOR_CALL 'public constructor <init> () declared in kotlin.KotlinNullPointerException' type=kotlin.KotlinNullPointerException origin=null
-            BRANCH
-              if: CONST Boolean type=kotlin.Boolean value=true
-              then: GET_VAR 'val tmp_1: kotlin.collections.MutableList<kotlin.Any>? [val] declared in <root>.test' type=kotlin.collections.MutableList<kotlin.Int> origin=null
+        $receiver: CALL 'public final fun CHECK_NOT_NULL <T0> (arg0: T0 of kotlin.internal.ir.CHECK_NOT_NULL?): T0 of kotlin.internal.ir.CHECK_NOT_NULL declared in kotlin.internal.ir' type=kotlin.collections.MutableList<kotlin.Any> origin=EXCLEXCL
+          <T0>: kotlin.collections.MutableList<kotlin.Any>
+          arg0: CALL 'public abstract fun f (): kotlin.collections.MutableList<kotlin.Any> declared in <root>.X' type=kotlin.collections.MutableList<kotlin.Any>? origin=null
+            $this: GET_VAR 'nx: <root>.X? declared in <root>.test' type=<root>.X? origin=null
         element: CONST Int type=kotlin.Int value=6
   FUN name:testExtensionReceiver visibility:public modality:FINAL <> ($receiver:kotlin.collections.MutableList<kotlin.Any>) returnType:kotlin.Unit
     $receiver: VALUE_PARAMETER name:<this> type:kotlin.collections.MutableList<kotlin.Any>