diff --git a/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ClassGenerator.kt b/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ClassGenerator.kt
index cdd206cc1b2..a74fd7e172b 100644
--- a/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ClassGenerator.kt
+++ b/compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/ClassGenerator.kt
@@ -279,7 +279,7 @@ class ClassGenerator(
         else {
             val substitutor =
                 TypeSubstitutor.create(
-                    overridden.original.typeParameters.associate {
+                    overridden.typeParameters.associate {
                         val delegatedDefaultType = delegated.typeParameters[it.index].defaultType
                         it.typeConstructor to TypeProjectionImpl(delegatedDefaultType)
                     }
diff --git a/compiler/testData/ir/irText/declarations/parameters/delegatedMembers.txt b/compiler/testData/ir/irText/declarations/parameters/delegatedMembers.txt
index 9b3fede09da..0a8a8b5dd3b 100644
--- a/compiler/testData/ir/irText/declarations/parameters/delegatedMembers.txt
+++ b/compiler/testData/ir/irText/declarations/parameters/delegatedMembers.txt
@@ -1,45 +1,35 @@
 FILE fqName:<root> fileName:/delegatedMembers.kt
-  CLASS INTERFACE name:IBase modality:ABSTRACT visibility:public flags:
+  CLASS INTERFACE name:IBase modality:ABSTRACT visibility:public flags: superTypes:[kotlin.Any]
     $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:IBase<T> flags:
-    superClasses:
-      CLASS IR_EXTERNAL_DECLARATION_STUB CLASS name:Any modality:OPEN visibility:public flags:
-    TYPE_PARAMETER name:T index:0 variance: upperBounds:[kotlin.Any?]
-      superClassifiers:
-        CLASS IR_EXTERNAL_DECLARATION_STUB CLASS name:Any modality:OPEN visibility:public flags:
-    FUN name:foo visibility:public modality:ABSTRACT <> ($this:IBase<T>, x:kotlin.Int) returnType:Unit flags:
+    TYPE_PARAMETER name:T index:0 variance: superTypes:[kotlin.Any?]
+    FUN name:foo visibility:public modality:ABSTRACT <> ($this:IBase<T>, x:kotlin.Int) returnType:kotlin.Unit flags:
       $this: VALUE_PARAMETER name:<this> type:IBase<T> flags:
       VALUE_PARAMETER name:x index:0 type:kotlin.Int flags:
-    PROPERTY name:bar type:kotlin.Int visibility:public modality:ABSTRACT flags:val
-      FUN DEFAULT_PROPERTY_ACCESSOR name:<get-bar> visibility:public modality:ABSTRACT <> ($this:IBase<T>) returnType:Int flags:
-        correspondingProperty: PROPERTY name:bar type:kotlin.Int visibility:public modality:ABSTRACT flags:val
+    PROPERTY name:bar visibility:public modality:ABSTRACT flags:val
+      FUN DEFAULT_PROPERTY_ACCESSOR name:<get-bar> visibility:public modality:ABSTRACT <> ($this:IBase<T>) returnType:kotlin.Int flags:
+        correspondingProperty: PROPERTY name:bar visibility:public modality:ABSTRACT flags:val
         $this: VALUE_PARAMETER name:<this> type:IBase<T> flags:
-    FUN name:qux visibility:public modality:ABSTRACT <X> ($this:IBase<T>, t:T, x:X) returnType:Unit flags:
-      TYPE_PARAMETER name:X index:0 variance: upperBounds:[kotlin.Any?]
-        superClassifiers:
-          CLASS IR_EXTERNAL_DECLARATION_STUB CLASS name:Any modality:OPEN visibility:public flags:
+    FUN name:qux visibility:public modality:ABSTRACT <X> ($this:IBase<T>, t:T, x:X) returnType:kotlin.Unit flags:
+      TYPE_PARAMETER name:X index:0 variance: superTypes:[kotlin.Any?]
       $this: VALUE_PARAMETER name:<this> type:IBase<T> flags:
       VALUE_PARAMETER name:t index:0 type:T flags:
       VALUE_PARAMETER name:x index:1 type:X flags:
-    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:Boolean flags:
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean flags:
       overridden:
-        FUN IR_EXTERNAL_DECLARATION_STUB name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:Boolean flags:
+        FUN IR_EXTERNAL_DECLARATION_STUB name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean flags:
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any flags:
       VALUE_PARAMETER name:other index:0 type:kotlin.Any? flags:
-    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:Int flags:
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int flags:
       overridden:
-        FUN IR_EXTERNAL_DECLARATION_STUB name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:Int flags:
+        FUN IR_EXTERNAL_DECLARATION_STUB name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int flags:
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any flags:
-    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:String flags:
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String flags:
       overridden:
-        FUN IR_EXTERNAL_DECLARATION_STUB name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:String flags:
+        FUN IR_EXTERNAL_DECLARATION_STUB name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String flags:
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any flags:
-  CLASS CLASS name:Test modality:FINAL visibility:public flags:
+  CLASS CLASS name:Test modality:FINAL visibility:public flags: superTypes:[IBase<TT>]
     $this: VALUE_PARAMETER INSTANCE_RECEIVER name:<this> type:Test<TT> flags:
-    superClasses:
-      CLASS INTERFACE name:IBase modality:ABSTRACT visibility:public flags:
-    TYPE_PARAMETER name:TT index:0 variance: upperBounds:[kotlin.Any?]
-      superClassifiers:
-        CLASS IR_EXTERNAL_DECLARATION_STUB CLASS name:Any modality:OPEN visibility:public flags:
+    TYPE_PARAMETER name:TT index:0 variance: superTypes:[kotlin.Any?]
     CONSTRUCTOR visibility:public <> (impl:IBase<TT>) returnType:Test<TT> flags:primary
       VALUE_PARAMETER name:impl index:0 type:IBase<TT> flags:
       BLOCK_BODY
@@ -48,12 +38,10 @@ FILE fqName:<root> fileName:/delegatedMembers.kt
     FIELD DELEGATE name:Test$IBase$delegate type:IBase<TT> visibility:private flags:final
       EXPRESSION_BODY
         GET_VAR 'value-parameter impl: IBase<TT>' type=IBase<TT> origin=null
-    FUN DELEGATED_MEMBER name:qux visibility:public modality:OPEN <X> ($this:Test<TT>, t:TT, x:X) returnType:Unit flags:
+    FUN DELEGATED_MEMBER name:qux visibility:public modality:OPEN <X> ($this:Test<TT>, t:TT, x:X) returnType:kotlin.Unit flags:
       overridden:
-        FUN name:qux visibility:public modality:ABSTRACT <X> ($this:IBase<T>, t:T, x:X) returnType:Unit flags:
-      TYPE_PARAMETER name:X index:0 variance: upperBounds:[kotlin.Any?]
-        superClassifiers:
-          CLASS IR_EXTERNAL_DECLARATION_STUB CLASS name:Any modality:OPEN visibility:public flags:
+        FUN name:qux visibility:public modality:ABSTRACT <X> ($this:IBase<T>, t:T, x:X) returnType:kotlin.Unit flags:
+      TYPE_PARAMETER name:X index:0 variance: superTypes:[kotlin.Any?]
       $this: VALUE_PARAMETER name:<this> type:Test<TT> flags:
       VALUE_PARAMETER name:t index:0 type:TT flags:
       VALUE_PARAMETER name:x index:1 type:X flags:
@@ -64,9 +52,9 @@ FILE fqName:<root> fileName:/delegatedMembers.kt
             receiver: GET_VAR 'this@Test: Test<TT>' type=Test<TT> origin=null
           t: GET_VAR 'value-parameter t: TT' type=TT origin=null
           x: GET_VAR 'value-parameter x: X' type=X origin=null
-    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:Test<TT>, x:kotlin.Int) returnType:Unit flags:
+    FUN DELEGATED_MEMBER name:foo visibility:public modality:OPEN <> ($this:Test<TT>, x:kotlin.Int) returnType:kotlin.Unit flags:
       overridden:
-        FUN name:foo visibility:public modality:ABSTRACT <> ($this:IBase<T>, x:kotlin.Int) returnType:Unit flags:
+        FUN name:foo visibility:public modality:ABSTRACT <> ($this:IBase<T>, x:kotlin.Int) returnType:kotlin.Unit flags:
       $this: VALUE_PARAMETER name:<this> type:Test<TT> flags:
       VALUE_PARAMETER name:x index:0 type:kotlin.Int flags:
       BLOCK_BODY
@@ -74,28 +62,27 @@ FILE fqName:<root> fileName:/delegatedMembers.kt
           $this: GET_FIELD '`Test$IBase$delegate`: IBase<TT>' type=IBase<TT> origin=null
             receiver: GET_VAR 'this@Test: Test<TT>' type=Test<TT> origin=null
           x: GET_VAR 'value-parameter x: Int' type=kotlin.Int origin=null
-    PROPERTY DELEGATED_MEMBER name:bar type:kotlin.Int visibility:public modality:OPEN flags:val
-      FUN DELEGATED_MEMBER name:<get-bar> visibility:public modality:OPEN <> ($this:Test<TT>) returnType:Int flags:
-        correspondingProperty: PROPERTY DELEGATED_MEMBER name:bar type:kotlin.Int visibility:public modality:OPEN flags:val
+    PROPERTY DELEGATED_MEMBER name:bar visibility:public modality:OPEN flags:val
+      FUN DELEGATED_MEMBER name:<get-bar> visibility:public modality:OPEN <> ($this:Test<TT>) returnType:kotlin.Int flags:
+        correspondingProperty: PROPERTY DELEGATED_MEMBER name:bar visibility:public modality:OPEN flags:val
         overridden:
-          FUN DEFAULT_PROPERTY_ACCESSOR name:<get-bar> visibility:public modality:ABSTRACT <> ($this:IBase<T>) returnType:Int flags:
+          FUN DEFAULT_PROPERTY_ACCESSOR name:<get-bar> visibility:public modality:ABSTRACT <> ($this:IBase<T>) returnType:kotlin.Int flags:
         $this: VALUE_PARAMETER name:<this> type:Test<TT> flags:
         BLOCK_BODY
           RETURN type=kotlin.Nothing from='<get-bar>(): Int'
             CALL '<get-bar>(): Int' type=kotlin.Int origin=null
               $this: GET_FIELD '`Test$IBase$delegate`: IBase<TT>' type=IBase<TT> origin=null
                 receiver: GET_VAR 'this@Test: Test<TT>' type=Test<TT> origin=null
-    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:Boolean flags:
+    FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean flags:
       overridden:
-        FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:Boolean flags:
+        FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean flags:
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any flags:
       VALUE_PARAMETER name:other index:0 type:kotlin.Any? flags:
-    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:Int flags:
+    FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int flags:
       overridden:
-        FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:Int flags:
+        FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int flags:
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any flags:
-    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:String flags:
+    FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String flags:
       overridden:
-        FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:String flags:
+        FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String flags:
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any flags:
-