diff --git a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/ir/IrUtils.kt b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/ir/IrUtils.kt
index 308fe30574a..2e72dc84a47 100644
--- a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/ir/IrUtils.kt
+++ b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/ir/IrUtils.kt
@@ -113,7 +113,7 @@ val IrType.erasedUpperBound: IrClass
     get() = when (val classifier = classifierOrNull) {
         is IrClassSymbol -> classifier.owner
         is IrTypeParameterSymbol -> classifier.owner.erasedUpperBound
-        else -> throw IllegalStateException()
+        else -> error(render())
     }
 
 /**
diff --git a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/RenderIrElement.kt b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/RenderIrElement.kt
index d796be3d76c..f0608c1c501 100644
--- a/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/RenderIrElement.kt
+++ b/compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/RenderIrElement.kt
@@ -18,6 +18,7 @@ import org.jetbrains.kotlin.ir.symbols.IrTypeAliasSymbol
 import org.jetbrains.kotlin.ir.symbols.IrVariableSymbol
 import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.types.impl.ReturnTypeIsNotInitializedException
+import org.jetbrains.kotlin.ir.types.impl.originalKotlinType
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
 import org.jetbrains.kotlin.renderer.DescriptorRenderer
 import org.jetbrains.kotlin.types.Variance
@@ -103,7 +104,7 @@ class RenderIrElementVisitor(private val normalizeNames: Boolean = false) : IrEl
         when (this) {
             is IrDynamicType -> "dynamic"
 
-            is IrErrorType -> "IrErrorType"
+            is IrErrorType -> "IrErrorType($originalKotlinType)"
 
             is IrSimpleType -> buildTrimEnd {
                 append(classifier.renderClassifierFqn())
diff --git a/compiler/testData/ir/irText/declarations/parameters/useNextParamInLambda.fir.txt b/compiler/testData/ir/irText/declarations/parameters/useNextParamInLambda.fir.txt
index eaaf0f56541..7bee7df5014 100644
--- a/compiler/testData/ir/irText/declarations/parameters/useNextParamInLambda.fir.txt
+++ b/compiler/testData/ir/irText/declarations/parameters/useNextParamInLambda.fir.txt
@@ -2,11 +2,11 @@ FILE fqName:<root> fileName:/useNextParamInLambda.kt
   FUN name:f visibility:public modality:FINAL <> (f1:kotlin.Function0<kotlin.String>, f2:kotlin.Function0<kotlin.String>) returnType:kotlin.String
     VALUE_PARAMETER name:f1 index:0 type:kotlin.Function0<kotlin.String>
       EXPRESSION_BODY
-        FUN_EXPR type=kotlin.Function0<IrErrorType> origin=LAMBDA
-          FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:IrErrorType
+        FUN_EXPR type=kotlin.Function0<IrErrorType(null)> origin=LAMBDA
+          FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:IrErrorType(null)
             BLOCK_BODY
-              RETURN type=kotlin.Nothing from='local final fun <anonymous> (): IrErrorType declared in <root>.f'
-                ERROR_CALL 'Unresolved reference: <Unresolved name: f2>#' type=IrErrorType
+              RETURN type=kotlin.Nothing from='local final fun <anonymous> (): IrErrorType(null) declared in <root>.f'
+                ERROR_CALL 'Unresolved reference: <Unresolved name: f2>#' type=IrErrorType(null)
     VALUE_PARAMETER name:f2 index:1 type:kotlin.Function0<kotlin.String>
       EXPRESSION_BODY
         FUN_EXPR type=kotlin.Function0<kotlin.String> origin=LAMBDA
diff --git a/compiler/testData/ir/irText/errors/unresolvedReference.fir.txt b/compiler/testData/ir/irText/errors/unresolvedReference.fir.txt
index e84339d9fff..97e9525359b 100644
--- a/compiler/testData/ir/irText/errors/unresolvedReference.fir.txt
+++ b/compiler/testData/ir/irText/errors/unresolvedReference.fir.txt
@@ -1,39 +1,39 @@
 FILE fqName:<root> fileName:/unresolvedReference.kt
   PROPERTY name:test1 visibility:public modality:FINAL [val]
-    FIELD PROPERTY_BACKING_FIELD name:test1 type:IrErrorType visibility:private [final,static]
+    FIELD PROPERTY_BACKING_FIELD name:test1 type:IrErrorType(null) visibility:private [final,static]
       EXPRESSION_BODY
-        ERROR_CALL 'Unresolved reference: <Unresolved name: unresolved>#' type=IrErrorType
-    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test1> visibility:public modality:FINAL <> () returnType:IrErrorType
+        ERROR_CALL 'Unresolved reference: <Unresolved name: unresolved>#' type=IrErrorType(null)
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test1> visibility:public modality:FINAL <> () returnType:IrErrorType(null)
       correspondingProperty: PROPERTY name:test1 visibility:public modality:FINAL [val]
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public final fun <get-test1> (): IrErrorType declared in <root>'
-          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test1 type:IrErrorType visibility:private [final,static]' type=IrErrorType origin=null
+        RETURN type=kotlin.Nothing from='public final fun <get-test1> (): IrErrorType(null) declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test1 type:IrErrorType(null) visibility:private [final,static]' type=IrErrorType(null) origin=null
   PROPERTY name:test2 visibility:public modality:FINAL [val]
-    FIELD PROPERTY_BACKING_FIELD name:test2 type:IrErrorType visibility:private [final,static]
+    FIELD PROPERTY_BACKING_FIELD name:test2 type:IrErrorType(null) visibility:private [final,static]
       EXPRESSION_BODY
-        ERROR_CALL 'Unresolved reference: <Unresolved name: unresolved>#' type=IrErrorType
-    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test2> visibility:public modality:FINAL <> () returnType:IrErrorType
+        ERROR_CALL 'Unresolved reference: <Unresolved name: unresolved>#' type=IrErrorType(null)
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test2> visibility:public modality:FINAL <> () returnType:IrErrorType(null)
       correspondingProperty: PROPERTY name:test2 visibility:public modality:FINAL [val]
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public final fun <get-test2> (): IrErrorType declared in <root>'
-          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test2 type:IrErrorType visibility:private [final,static]' type=IrErrorType origin=null
+        RETURN type=kotlin.Nothing from='public final fun <get-test2> (): IrErrorType(null) declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test2 type:IrErrorType(null) visibility:private [final,static]' type=IrErrorType(null) origin=null
   PROPERTY name:test3 visibility:public modality:FINAL [val]
-    FIELD PROPERTY_BACKING_FIELD name:test3 type:IrErrorType visibility:private [final,static]
+    FIELD PROPERTY_BACKING_FIELD name:test3 type:IrErrorType(null) visibility:private [final,static]
       EXPRESSION_BODY
-        ERROR_CALL 'Unresolved reference: <Unresolved name: unresolved>#' type=IrErrorType
+        ERROR_CALL 'Unresolved reference: <Unresolved name: unresolved>#' type=IrErrorType(null)
           CONST Int type=kotlin.Int value=56
-    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test3> visibility:public modality:FINAL <> () returnType:IrErrorType
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test3> visibility:public modality:FINAL <> () returnType:IrErrorType(null)
       correspondingProperty: PROPERTY name:test3 visibility:public modality:FINAL [val]
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public final fun <get-test3> (): IrErrorType declared in <root>'
-          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test3 type:IrErrorType visibility:private [final,static]' type=IrErrorType origin=null
+        RETURN type=kotlin.Nothing from='public final fun <get-test3> (): IrErrorType(null) declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test3 type:IrErrorType(null) visibility:private [final,static]' type=IrErrorType(null) origin=null
   PROPERTY name:test4 visibility:public modality:FINAL [val]
-    FIELD PROPERTY_BACKING_FIELD name:test4 type:IrErrorType visibility:private [final,static]
+    FIELD PROPERTY_BACKING_FIELD name:test4 type:IrErrorType(null) visibility:private [final,static]
       EXPRESSION_BODY
-        ERROR_CALL 'Unresolved reference: <Ambiguity: times, [kotlin/Int.times, kotlin/Int.times, kotlin/Int.times, kotlin/Int.times, kotlin/Int.times, kotlin/Int.times]>#' type=IrErrorType
-          ERROR_EXPR 'No right operand' type=IrErrorType
-    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test4> visibility:public modality:FINAL <> () returnType:IrErrorType
+        ERROR_CALL 'Unresolved reference: <Ambiguity: times, [kotlin/Int.times, kotlin/Int.times, kotlin/Int.times, kotlin/Int.times, kotlin/Int.times, kotlin/Int.times]>#' type=IrErrorType(null)
+          ERROR_EXPR 'No right operand' type=IrErrorType(null)
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test4> visibility:public modality:FINAL <> () returnType:IrErrorType(null)
       correspondingProperty: PROPERTY name:test4 visibility:public modality:FINAL [val]
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public final fun <get-test4> (): IrErrorType declared in <root>'
-          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test4 type:IrErrorType visibility:private [final,static]' type=IrErrorType origin=null
+        RETURN type=kotlin.Nothing from='public final fun <get-test4> (): IrErrorType(null) declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test4 type:IrErrorType(null) visibility:private [final,static]' type=IrErrorType(null) origin=null
diff --git a/compiler/testData/ir/irText/errors/unresolvedReference.txt b/compiler/testData/ir/irText/errors/unresolvedReference.txt
index cf5d57acaae..08ca416ea47 100644
--- a/compiler/testData/ir/irText/errors/unresolvedReference.txt
+++ b/compiler/testData/ir/irText/errors/unresolvedReference.txt
@@ -1,39 +1,39 @@
 FILE fqName:<root> fileName:/unresolvedReference.kt
   PROPERTY name:test1 visibility:public modality:FINAL [val]
-    FIELD PROPERTY_BACKING_FIELD name:test1 type:IrErrorType visibility:private [final,static]
+    FIELD PROPERTY_BACKING_FIELD name:test1 type:IrErrorType([ERROR : Type for unresolved]) visibility:private [final,static]
       EXPRESSION_BODY
-        ERROR_CALL 'unresolved' type=IrErrorType
-    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test1> visibility:public modality:FINAL <> () returnType:IrErrorType
+        ERROR_CALL 'unresolved' type=IrErrorType([ERROR : ])
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test1> visibility:public modality:FINAL <> () returnType:IrErrorType([ERROR : Type for unresolved])
       correspondingProperty: PROPERTY name:test1 visibility:public modality:FINAL [val]
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public final fun <get-test1> (): IrErrorType declared in <root>'
-          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test1 type:IrErrorType visibility:private [final,static]' type=IrErrorType origin=null
+        RETURN type=kotlin.Nothing from='public final fun <get-test1> (): IrErrorType([ERROR : Type for unresolved]) declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test1 type:IrErrorType([ERROR : Type for unresolved]) visibility:private [final,static]' type=IrErrorType([ERROR : Type for unresolved]) origin=null
   PROPERTY name:test2 visibility:public modality:FINAL [val]
-    FIELD PROPERTY_BACKING_FIELD name:test2 type:IrErrorType visibility:private [final,static]
+    FIELD PROPERTY_BACKING_FIELD name:test2 type:IrErrorType([ERROR : Unresolved]) visibility:private [final,static]
       EXPRESSION_BODY
-        ERROR_CALL 'unresolved()' type=IrErrorType
-    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test2> visibility:public modality:FINAL <> () returnType:IrErrorType
+        ERROR_CALL 'unresolved()' type=IrErrorType([ERROR : ])
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test2> visibility:public modality:FINAL <> () returnType:IrErrorType([ERROR : Unresolved])
       correspondingProperty: PROPERTY name:test2 visibility:public modality:FINAL [val]
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public final fun <get-test2> (): IrErrorType declared in <root>'
-          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test2 type:IrErrorType visibility:private [final,static]' type=IrErrorType origin=null
+        RETURN type=kotlin.Nothing from='public final fun <get-test2> (): IrErrorType([ERROR : Unresolved]) declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test2 type:IrErrorType([ERROR : Unresolved]) visibility:private [final,static]' type=IrErrorType([ERROR : Unresolved]) origin=null
   PROPERTY name:test3 visibility:public modality:FINAL [val]
-    FIELD PROPERTY_BACKING_FIELD name:test3 type:IrErrorType visibility:private [final,static]
+    FIELD PROPERTY_BACKING_FIELD name:test3 type:IrErrorType([ERROR : Type for 42.unresolved(56)]) visibility:private [final,static]
       EXPRESSION_BODY
-        ERROR_CALL 'unresolved(56)' type=IrErrorType
+        ERROR_CALL 'unresolved(56)' type=IrErrorType([ERROR : ])
           receiver: CONST Int type=kotlin.Int value=42
           CONST Int type=kotlin.Int value=56
-    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test3> visibility:public modality:FINAL <> () returnType:IrErrorType
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test3> visibility:public modality:FINAL <> () returnType:IrErrorType([ERROR : Type for 42.unresolved(56)])
       correspondingProperty: PROPERTY name:test3 visibility:public modality:FINAL [val]
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public final fun <get-test3> (): IrErrorType declared in <root>'
-          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test3 type:IrErrorType visibility:private [final,static]' type=IrErrorType origin=null
+        RETURN type=kotlin.Nothing from='public final fun <get-test3> (): IrErrorType([ERROR : Type for 42.unresolved(56)]) declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test3 type:IrErrorType([ERROR : Type for 42.unresolved(56)]) visibility:private [final,static]' type=IrErrorType([ERROR : Type for 42.unresolved(56)]) origin=null
   PROPERTY name:test4 visibility:public modality:FINAL [val]
-    FIELD PROPERTY_BACKING_FIELD name:test4 type:IrErrorType visibility:private [final,static]
+    FIELD PROPERTY_BACKING_FIELD name:test4 type:IrErrorType([ERROR : Type for 42 *]) visibility:private [final,static]
       EXPRESSION_BODY
-        ERROR_EXPR '42 *' type=IrErrorType
-    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test4> visibility:public modality:FINAL <> () returnType:IrErrorType
+        ERROR_EXPR '42 *' type=IrErrorType([ERROR : ])
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test4> visibility:public modality:FINAL <> () returnType:IrErrorType([ERROR : Type for 42 *])
       correspondingProperty: PROPERTY name:test4 visibility:public modality:FINAL [val]
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public final fun <get-test4> (): IrErrorType declared in <root>'
-          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test4 type:IrErrorType visibility:private [final,static]' type=IrErrorType origin=null
+        RETURN type=kotlin.Nothing from='public final fun <get-test4> (): IrErrorType([ERROR : Type for 42 *]) declared in <root>'
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test4 type:IrErrorType([ERROR : Type for 42 *]) visibility:private [final,static]' type=IrErrorType([ERROR : Type for 42 *]) origin=null
diff --git a/compiler/testData/ir/irText/expressions/sam/arrayAsVarargAfterSamArgument.fir.txt b/compiler/testData/ir/irText/expressions/sam/arrayAsVarargAfterSamArgument.fir.txt
index 748fa77c30f..03393bf3bec 100644
--- a/compiler/testData/ir/irText/expressions/sam/arrayAsVarargAfterSamArgument.fir.txt
+++ b/compiler/testData/ir/irText/expressions/sam/arrayAsVarargAfterSamArgument.fir.txt
@@ -53,8 +53,8 @@ FILE fqName:<root> fileName:/arrayAsVarargAfterSamArgument.kt
           strs: VARARG type=kotlin.Array<out kotlin.String?>? varargElementType=kotlin.String?
             SPREAD_ELEMENT
               GET_VAR 'arr: kotlin.Array<kotlin.String> declared in <root>.test' type=kotlin.Array<kotlin.String> origin=null
-      VAR name:i1 type:IrErrorType [val]
-        ERROR_CALL 'Unresolved reference: <Ambiguity: Test, [/Test.Test, /Test.Test]>#' type=IrErrorType
+      VAR name:i1 type:IrErrorType(null) [val]
+        ERROR_CALL 'Unresolved reference: <Ambiguity: Test, [/Test.Test, /Test.Test]>#' type=IrErrorType(null)
           FUN_EXPR type=kotlin.Function0<kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Unit
               BLOCK_BODY
@@ -72,8 +72,8 @@ FILE fqName:<root> fileName:/arrayAsVarargAfterSamArgument.kt
           strs: VARARG type=kotlin.Array<out kotlin.String?>? varargElementType=kotlin.String?
             SPREAD_ELEMENT
               GET_VAR 'arr: kotlin.Array<kotlin.String> declared in <root>.test' type=kotlin.Array<kotlin.String> origin=null
-      VAR name:i3 type:IrErrorType [val]
-        ERROR_CALL 'Unresolved reference: <Ambiguity: Test, [/Test.Test, /Test.Test]>#' type=IrErrorType
+      VAR name:i3 type:IrErrorType(null) [val]
+        ERROR_CALL 'Unresolved reference: <Ambiguity: Test, [/Test.Test, /Test.Test]>#' type=IrErrorType(null)
           FUN_EXPR type=kotlin.Function0<kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Unit
               BLOCK_BODY
@@ -125,7 +125,7 @@ FILE fqName:<root> fileName:/arrayAsVarargAfterSamArgument.kt
           strs: VARARG type=kotlin.Array<out kotlin.String?>? varargElementType=kotlin.String?
             SPREAD_ELEMENT
               GET_VAR 'arr: kotlin.Array<kotlin.String> declared in <root>.test' type=kotlin.Array<kotlin.String> origin=null
-      ERROR_CALL 'Unresolved reference: <Unresolved name: foo2>#' type=IrErrorType
+      ERROR_CALL 'Unresolved reference: <Unresolved name: foo2>#' type=IrErrorType(null)
         FUN_EXPR type=kotlin.Function0<kotlin.Unit> origin=LAMBDA
           FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Unit
             BLOCK_BODY
@@ -137,7 +137,7 @@ FILE fqName:<root> fileName:/arrayAsVarargAfterSamArgument.kt
               RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Unit declared in <root>.test'
                 GET_OBJECT 'CLASS IR_EXTERNAL_DECLARATION_STUB OBJECT name:Unit modality:FINAL visibility:public superTypes:[kotlin.Any]' type=kotlin.Unit
         GET_VAR 'arr: kotlin.Array<kotlin.String> declared in <root>.test' type=kotlin.Array<kotlin.String> origin=null
-      ERROR_CALL 'Unresolved reference: <Unresolved name: foo2>#' type=IrErrorType
+      ERROR_CALL 'Unresolved reference: <Unresolved name: foo2>#' type=IrErrorType(null)
         GET_VAR 'r: java.lang.Runnable declared in <root>.test' type=java.lang.Runnable origin=null
         FUN_EXPR type=kotlin.Function0<kotlin.Unit> origin=LAMBDA
           FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Unit
@@ -145,7 +145,7 @@ FILE fqName:<root> fileName:/arrayAsVarargAfterSamArgument.kt
               RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Unit declared in <root>.test'
                 GET_OBJECT 'CLASS IR_EXTERNAL_DECLARATION_STUB OBJECT name:Unit modality:FINAL visibility:public superTypes:[kotlin.Any]' type=kotlin.Unit
         CONST String type=kotlin.String value=""
-      ERROR_CALL 'Unresolved reference: <Unresolved name: foo2>#' type=IrErrorType
+      ERROR_CALL 'Unresolved reference: <Unresolved name: foo2>#' type=IrErrorType(null)
         FUN_EXPR type=kotlin.Function0<kotlin.Unit> origin=LAMBDA
           FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Unit
             BLOCK_BODY
@@ -157,7 +157,7 @@ FILE fqName:<root> fileName:/arrayAsVarargAfterSamArgument.kt
               RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Unit declared in <root>.test'
                 GET_OBJECT 'CLASS IR_EXTERNAL_DECLARATION_STUB OBJECT name:Unit modality:FINAL visibility:public superTypes:[kotlin.Any]' type=kotlin.Unit
         GET_VAR 'arr: kotlin.Array<kotlin.String> declared in <root>.test' type=kotlin.Array<kotlin.String> origin=null
-      ERROR_CALL 'Unresolved reference: <Unresolved name: foo2>#' type=IrErrorType
+      ERROR_CALL 'Unresolved reference: <Unresolved name: foo2>#' type=IrErrorType(null)
         GET_VAR 'r: java.lang.Runnable declared in <root>.test' type=java.lang.Runnable origin=null
         FUN_EXPR type=kotlin.Function0<kotlin.Unit> origin=LAMBDA
           FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Unit
diff --git a/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.txt b/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.txt
index 7ffbffdcde0..b5b65b6c620 100644
--- a/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.txt
+++ b/compiler/testData/ir/irText/types/castsInsideCoroutineInference.fir.txt
@@ -61,21 +61,21 @@ FILE fqName:<root> fileName:/castsInsideCoroutineInference.kt
     BLOCK_BODY
       RETURN type=kotlin.Nothing from='public final fun unsafeFlow <T> (block: @[ExtensionFunctionType] kotlin.coroutines.SuspendFunction1<<root>.FlowCollector<T of <root>.unsafeFlow>, kotlin.Unit>): <root>.Flow<T of <root>.unsafeFlow> [inline] declared in <root>'
         CALL 'public final fun TODO (): kotlin.Nothing [inline] declared in kotlin.StandardKt' type=kotlin.Nothing origin=null
-  FUN name:onCompletion visibility:public modality:FINAL <T> ($receiver:<root>.Flow<T of <root>.onCompletion>, action:kotlin.coroutines.SuspendFunction1<kotlin.Throwable?, kotlin.Unit>) returnType:IrErrorType
+  FUN name:onCompletion visibility:public modality:FINAL <T> ($receiver:<root>.Flow<T of <root>.onCompletion>, action:kotlin.coroutines.SuspendFunction1<kotlin.Throwable?, kotlin.Unit>) returnType:IrErrorType(null)
     annotations:
       Deprecated(message = 'binary compatibility with a version w/o FlowCollector receiver', replaceWith = <null>, level = GET_ENUM 'ENUM_ENTRY IR_EXTERNAL_DECLARATION_STUB name:HIDDEN' type=kotlin.DeprecationLevel)
     TYPE_PARAMETER name:T index:0 variance: superTypes:[kotlin.Any?]
     $receiver: VALUE_PARAMETER name:<this> type:<root>.Flow<T of <root>.onCompletion>
     VALUE_PARAMETER name:action index:0 type:kotlin.coroutines.SuspendFunction1<kotlin.Throwable?, kotlin.Unit>
     BLOCK_BODY
-      RETURN type=kotlin.Nothing from='public final fun onCompletion <T> (action: kotlin.coroutines.SuspendFunction1<kotlin.Throwable?, kotlin.Unit>): IrErrorType declared in <root>'
-        ERROR_CALL 'Unresolved reference: <Ambiguity: onCompletion, [/onCompletion, /onCompletion]>#' type=IrErrorType
+      RETURN type=kotlin.Nothing from='public final fun onCompletion <T> (action: kotlin.coroutines.SuspendFunction1<kotlin.Throwable?, kotlin.Unit>): IrErrorType(null) declared in <root>'
+        ERROR_CALL 'Unresolved reference: <Ambiguity: onCompletion, [/onCompletion, /onCompletion]>#' type=IrErrorType(null)
           FUN_EXPR type=kotlin.Function0<kotlin.Unit> origin=LAMBDA
             FUN LOCAL_FUNCTION_FOR_LAMBDA name:<anonymous> visibility:local modality:FINAL <> () returnType:kotlin.Unit
               BLOCK_BODY
                 CALL 'public abstract fun invoke (p1: P1 of kotlin.coroutines.SuspendFunction1): R of kotlin.coroutines.SuspendFunction1 [suspend,operator] declared in kotlin.coroutines.SuspendFunction1' type=kotlin.Unit origin=null
                   $this: GET_VAR 'action: kotlin.coroutines.SuspendFunction1<kotlin.Throwable?, kotlin.Unit> declared in <root>.onCompletion' type=kotlin.coroutines.SuspendFunction1<kotlin.Throwable?, kotlin.Unit> origin=VARIABLE_AS_FUNCTION
-                  p1: ERROR_CALL 'Unresolved reference: <Unresolved name: it>#' type=IrErrorType
+                  p1: ERROR_CALL 'Unresolved reference: <Unresolved name: it>#' type=IrErrorType(null)
   FUN name:asFairChannel visibility:private modality:FINAL <> ($receiver:<root>.CoroutineScope, flow:<root>.Flow<*>) returnType:<root>.ReceiveChannel<kotlin.Any>
     $receiver: VALUE_PARAMETER name:<this> type:<root>.CoroutineScope
     VALUE_PARAMETER name:flow index:0 type:<root>.Flow<*>