diff --git a/compiler/testData/compileJavaAgainstKotlin/class/ExtendsAbstractListT.txt b/compiler/testData/compileJavaAgainstKotlin/class/ExtendsAbstractListT.txt
index 3d18e1b2dff..0a34238bdb0 100644
--- a/compiler/testData/compileJavaAgainstKotlin/class/ExtendsAbstractListT.txt
+++ b/compiler/testData/compileJavaAgainstKotlin/class/ExtendsAbstractListT.txt
@@ -10,17 +10,17 @@ internal abstract class Mine</*0*/ T> : java.util.AbstractList<T> {
     public open /*fake_override*/ fun add(/*0*/ T!): kotlin.Boolean
     public open /*fake_override*/ fun add(/*0*/ kotlin.Int, /*1*/ T!): kotlin.Unit
     public open /*fake_override*/ fun addAll(/*0*/ kotlin.Collection<T!>): kotlin.Boolean
-    public open /*fake_override*/ fun addAll(/*0*/ kotlin.Int, /*1*/ (kotlin.MutableCollection<out T!>..kotlin.Collection<T!>?)): kotlin.Boolean
+    public open /*fake_override*/ fun addAll(/*0*/ kotlin.Int, /*1*/ kotlin.Collection<T!>): kotlin.Boolean
     public open /*fake_override*/ fun clear(): kotlin.Unit
     public open /*fake_override*/ fun contains(/*0*/ kotlin.Any?): kotlin.Boolean
     public open /*fake_override*/ fun containsAll(/*0*/ kotlin.Collection<kotlin.Any?>): kotlin.Boolean
     public abstract /*fake_override*/ fun get(/*0*/ kotlin.Int): T!
-    public open /*fake_override*/ fun indexOf(/*0*/ kotlin.Any!): kotlin.Int
+    public open /*fake_override*/ fun indexOf(/*0*/ kotlin.Any?): kotlin.Int
     public open /*fake_override*/ fun isEmpty(): kotlin.Boolean
-    public open /*fake_override*/ fun iterator(): kotlin.(Mutable)Iterator<T!>!
-    public open /*fake_override*/ fun lastIndexOf(/*0*/ kotlin.Any!): kotlin.Int
-    public open /*fake_override*/ fun listIterator(): kotlin.(Mutable)ListIterator<T!>!
-    public open /*fake_override*/ fun listIterator(/*0*/ kotlin.Int): kotlin.(Mutable)ListIterator<T!>!
+    public open /*fake_override*/ fun iterator(): kotlin.MutableIterator<T!>
+    public open /*fake_override*/ fun lastIndexOf(/*0*/ kotlin.Any?): kotlin.Int
+    public open /*fake_override*/ fun listIterator(): kotlin.MutableListIterator<T!>
+    public open /*fake_override*/ fun listIterator(/*0*/ kotlin.Int): kotlin.MutableListIterator<T!>
     invisible_fake open /*fake_override*/ fun outOfBoundsMsg(/*0*/ kotlin.Int): kotlin.String!
     invisible_fake open /*fake_override*/ fun rangeCheckForAdd(/*0*/ kotlin.Int): kotlin.Unit
     public open /*fake_override*/ fun remove(/*0*/ kotlin.Any?): kotlin.Boolean
@@ -30,7 +30,7 @@ internal abstract class Mine</*0*/ T> : java.util.AbstractList<T> {
     public open /*fake_override*/ fun retainAll(/*0*/ kotlin.Collection<kotlin.Any?>): kotlin.Boolean
     public open /*fake_override*/ fun set(/*0*/ kotlin.Int, /*1*/ T!): T!
     public abstract /*fake_override*/ fun size(): kotlin.Int
-    public open /*fake_override*/ fun subList(/*0*/ kotlin.Int, /*1*/ kotlin.Int): kotlin.(Mutable)List<T!>!
+    public open /*fake_override*/ fun subList(/*0*/ kotlin.Int, /*1*/ kotlin.Int): kotlin.MutableList<T!>
     public open /*fake_override*/ fun toArray(): kotlin.Array<(out) kotlin.Any!>!
     public open /*fake_override*/ fun </*0*/ T> toArray(/*0*/ kotlin.Array<(out) T!>!): kotlin.Array<(out) T!>!
 }
diff --git a/compiler/testData/compileJavaAgainstKotlin/class/ImplementsListString.txt b/compiler/testData/compileJavaAgainstKotlin/class/ImplementsListString.txt
index 4c097c488c3..c8e93e1d5fa 100644
--- a/compiler/testData/compileJavaAgainstKotlin/class/ImplementsListString.txt
+++ b/compiler/testData/compileJavaAgainstKotlin/class/ImplementsListString.txt
@@ -4,22 +4,22 @@ internal abstract class Mine : java.util.List<kotlin.String> {
     public constructor Mine()
     public abstract /*fake_override*/ fun add(/*0*/ kotlin.Int, /*1*/ kotlin.String!): kotlin.Unit
     public abstract /*fake_override*/ fun add(/*0*/ kotlin.String!): kotlin.Boolean
-    public abstract /*fake_override*/ fun addAll(/*0*/ (kotlin.MutableCollection<out kotlin.String!>..kotlin.Collection<kotlin.String!>?)): kotlin.Boolean
+    public abstract /*fake_override*/ fun addAll(/*0*/ kotlin.Collection<kotlin.String!>): kotlin.Boolean
     public abstract /*fake_override*/ fun addAll(/*0*/ kotlin.Int, /*1*/ (kotlin.MutableCollection<out kotlin.String!>..kotlin.Collection<kotlin.String!>?)): kotlin.Boolean
     public abstract /*fake_override*/ fun clear(): kotlin.Unit
-    public abstract /*fake_override*/ fun contains(/*0*/ kotlin.Any!): kotlin.Boolean
-    public abstract /*fake_override*/ fun containsAll(/*0*/ kotlin.(Mutable)Collection<*>!): kotlin.Boolean
+    public abstract /*fake_override*/ fun contains(/*0*/ kotlin.Any?): kotlin.Boolean
+    public abstract /*fake_override*/ fun containsAll(/*0*/ kotlin.Collection<*>): kotlin.Boolean
     public abstract /*fake_override*/ fun get(/*0*/ kotlin.Int): kotlin.String!
     public abstract /*fake_override*/ fun indexOf(/*0*/ kotlin.Any!): kotlin.Int
     public abstract /*fake_override*/ fun isEmpty(): kotlin.Boolean
-    public abstract /*fake_override*/ fun iterator(): kotlin.(Mutable)Iterator<kotlin.String!>!
+    public abstract /*fake_override*/ fun iterator(): kotlin.MutableIterator<kotlin.String!>
     public abstract /*fake_override*/ fun lastIndexOf(/*0*/ kotlin.Any!): kotlin.Int
     public abstract /*fake_override*/ fun listIterator(): kotlin.(Mutable)ListIterator<kotlin.String!>!
     public abstract /*fake_override*/ fun listIterator(/*0*/ kotlin.Int): kotlin.(Mutable)ListIterator<kotlin.String!>!
-    public abstract /*fake_override*/ fun remove(/*0*/ kotlin.Any!): kotlin.Boolean
+    public abstract /*fake_override*/ fun remove(/*0*/ kotlin.Any?): kotlin.Boolean
     public abstract /*fake_override*/ fun remove(/*0*/ kotlin.Int): kotlin.String!
-    public abstract /*fake_override*/ fun removeAll(/*0*/ kotlin.(Mutable)Collection<*>!): kotlin.Boolean
-    public abstract /*fake_override*/ fun retainAll(/*0*/ kotlin.(Mutable)Collection<*>!): kotlin.Boolean
+    public abstract /*fake_override*/ fun removeAll(/*0*/ kotlin.Collection<*>): kotlin.Boolean
+    public abstract /*fake_override*/ fun retainAll(/*0*/ kotlin.Collection<*>): kotlin.Boolean
     public abstract /*fake_override*/ fun set(/*0*/ kotlin.Int, /*1*/ kotlin.String!): kotlin.String!
     public abstract /*fake_override*/ fun size(): kotlin.Int
     public abstract /*fake_override*/ fun subList(/*0*/ kotlin.Int, /*1*/ kotlin.Int): kotlin.(Mutable)List<kotlin.String!>!
diff --git a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/ByteOverridesObject.txt b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/ByteOverridesObject.txt
index 001503d8b8d..2ceb1273a48 100644
--- a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/ByteOverridesObject.txt
+++ b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/ByteOverridesObject.txt
@@ -22,6 +22,6 @@ public/*package*/ open class ExtendsB : test.B {
 
 public/*package*/ open class ExtendsC : test.C {
     public/*package*/ constructor ExtendsC()
-    public open fun foo(): kotlin.Byte!
+    public open fun foo(): kotlin.Byte
     public/*package*/ open fun test(): kotlin.Unit
 }
diff --git a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesComparable.txt b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesComparable.txt
index 2b3b2080112..6328834735d 100644
--- a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesComparable.txt
+++ b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesComparable.txt
@@ -22,6 +22,6 @@ public/*package*/ open class ExtendsB : test.B {
 
 public/*package*/ open class ExtendsC : test.C {
     public/*package*/ constructor ExtendsC()
-    public open fun foo(): kotlin.Int!
+    public open fun foo(): kotlin.Int
     public/*package*/ open fun test(): kotlin.Unit
 }
diff --git a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesNumber.txt b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesNumber.txt
index c2628690147..e23a75459d8 100644
--- a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesNumber.txt
+++ b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesNumber.txt
@@ -22,6 +22,6 @@ public/*package*/ open class ExtendsB : test.B {
 
 public/*package*/ open class ExtendsC : test.C {
     public/*package*/ constructor ExtendsC()
-    public open fun foo(): kotlin.Int!
+    public open fun foo(): kotlin.Int
     public/*package*/ open fun test(): kotlin.Unit
 }
diff --git a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesObject.txt b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesObject.txt
index 961872949bb..d4f815b37c3 100644
--- a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesObject.txt
+++ b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/IntOverridesObject.txt
@@ -22,6 +22,6 @@ public/*package*/ open class ExtendsB : test.B {
 
 public/*package*/ open class ExtendsC : test.C {
     public/*package*/ constructor ExtendsC()
-    public open fun foo(): kotlin.Int!
+    public open fun foo(): kotlin.Int
     public/*package*/ open fun test(): kotlin.Unit
 }
diff --git a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/NullableIntOverridesObject.txt b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/NullableIntOverridesObject.txt
index 9411026f19b..172f848f148 100644
--- a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/NullableIntOverridesObject.txt
+++ b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/NullableIntOverridesObject.txt
@@ -22,6 +22,6 @@ public/*package*/ open class ExtendsB : test.B {
 
 public/*package*/ open class ExtendsC : test.C {
     public/*package*/ constructor ExtendsC()
-    public open fun foo(): kotlin.Int!
+    public open fun foo(): kotlin.Int?
     public/*package*/ open fun test(): kotlin.Unit
 }
diff --git a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/OverrideInJava.txt b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/OverrideInJava.txt
index 407ad2cb5e4..b337973dbde 100644
--- a/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/OverrideInJava.txt
+++ b/compiler/testData/compileJavaAgainstKotlin/method/primitiveOverride/OverrideInJava.txt
@@ -11,6 +11,6 @@ internal abstract class B : test.A<kotlin.Int> {
 
 public/*package*/ open class ExtendsB : test.B {
     public/*package*/ constructor ExtendsB()
-    public open fun foo(): kotlin.Int!
+    public open fun foo(): kotlin.Int
     public/*package*/ open fun test(): kotlin.Unit
 }
diff --git a/compiler/testData/loadJava/compiledJava/ClassDoesNotOverrideMethod.txt b/compiler/testData/loadJava/compiledJava/ClassDoesNotOverrideMethod.txt
index 25e55faf381..f9c862da9fa 100644
--- a/compiler/testData/loadJava/compiledJava/ClassDoesNotOverrideMethod.txt
+++ b/compiler/testData/loadJava/compiledJava/ClassDoesNotOverrideMethod.txt
@@ -6,7 +6,7 @@ public abstract class ClassDoesNotOverrideMethod : java.util.Date {
     invisible_fake final override /*1*/ /*fake_override*/ var fastTime: kotlin.Long
     public open override /*1*/ /*fake_override*/ fun after(/*0*/ p0: java.util.Date!): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun before(/*0*/ p0: java.util.Date!): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun clone(): kotlin.Any!
+    public open override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
     public open override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: java.util.Date!): kotlin.Int
     invisible_fake final override /*1*/ /*fake_override*/ fun getCalendarDate(): sun.util.calendar.BaseCalendar.Date!
     kotlin.deprecated(value = "Deprecated in Java") public open override /*1*/ /*fake_override*/ fun getDate(): kotlin.Int
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/InheritNullability.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/InheritNullability.txt
index e1fd0fc86de..4acef4ae49c 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/InheritNullability.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/InheritNullability.txt
@@ -4,11 +4,11 @@ public interface InheritNullability {
 
     public interface Sub : test.InheritNullability.Super {
         public abstract override /*1*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*1*/ fun foo(/*0*/ p0: kotlin.String!): kotlin.Unit
+        public abstract override /*1*/ fun foo(/*0*/ p0: kotlin.String): kotlin.Unit
     }
 
     public interface Super {
         public abstract fun dummy(): kotlin.Unit
-        public abstract fun foo(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String!): kotlin.Unit
+        public abstract fun foo(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String): kotlin.Unit
     }
 }
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/Kt3302.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/Kt3302.txt
index ff7c0e33b6c..c8baccc2a06 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/Kt3302.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/Kt3302.txt
@@ -4,12 +4,12 @@ public interface Kt3302 {
 
     public interface BSONObject {
         public abstract fun dummy(): kotlin.Unit
-        public abstract fun put(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String!, /*1*/ org.jetbrains.annotations.NotNull() p1: kotlin.Any!): kotlin.Any!
+        public abstract fun put(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String, /*1*/ org.jetbrains.annotations.NotNull() p1: kotlin.Any): kotlin.Any!
     }
 
     public interface BasicBSONObject : test.Kt3302.LinkedHashMap<kotlin.String!, kotlin.Any!>, test.Kt3302.BSONObject {
         public abstract override /*2*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*2*/ fun put(/*0*/ key: kotlin.String!, /*1*/ value: kotlin.Any!): kotlin.Any!
+        public abstract override /*2*/ fun put(/*0*/ key: kotlin.String, /*1*/ value: kotlin.Any): kotlin.Any!
     }
 
     public interface LinkedHashMap</*0*/ K, /*1*/ V> {
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/NotNullToNullable.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/NotNullToNullable.txt
index ea246554807..725c802b7ff 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/NotNullToNullable.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/NotNullToNullable.txt
@@ -4,11 +4,11 @@ public interface NotNullToNullable {
 
     public interface Sub : test.NotNullToNullable.Super {
         public abstract override /*1*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*1*/ fun foo(/*0*/ p: kotlin.String!): kotlin.Unit
+        public abstract override /*1*/ fun foo(/*0*/ p: kotlin.String): kotlin.Unit
     }
 
     public interface Super {
         public abstract fun dummy(): kotlin.Unit
-        public abstract fun foo(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String!): kotlin.Unit
+        public abstract fun foo(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String): kotlin.Unit
     }
 }
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/NullableToNotNull.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/NullableToNotNull.txt
index 99a6a6ef179..7b3bf60f07a 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/NullableToNotNull.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/NullableToNotNull.txt
@@ -4,7 +4,7 @@ public interface NullableToNotNull {
 
     public interface Sub : test.NullableToNotNull.Super {
         public abstract override /*1*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*1*/ fun foo(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String!): kotlin.Unit
+        public abstract override /*1*/ fun foo(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String): kotlin.Unit
     }
 
     public interface Super {
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/SubclassFromGenericAndNot.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/SubclassFromGenericAndNot.txt
index e5a07aef461..ef69af33b02 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/SubclassFromGenericAndNot.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/parameter/SubclassFromGenericAndNot.txt
@@ -9,11 +9,11 @@ public interface SubclassFromGenericAndNot {
 
     public interface NonGeneric {
         public abstract fun dummy(): kotlin.Unit
-        public abstract fun foo(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String!): kotlin.Unit
+        public abstract fun foo(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String): kotlin.Unit
     }
 
     public interface Sub : test.SubclassFromGenericAndNot.NonGeneric, test.SubclassFromGenericAndNot.Generic<kotlin.String!> {
         public abstract override /*2*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*2*/ fun foo(/*0*/ key: kotlin.String!): kotlin.Unit
+        public abstract override /*2*/ fun foo(/*0*/ key: kotlin.String): kotlin.Unit
     }
 }
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNotNullJavaSubtype.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNotNullJavaSubtype.txt
index b432f192568..6b95bff2fe8 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNotNullJavaSubtype.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNotNullJavaSubtype.txt
@@ -4,7 +4,7 @@ public interface AddNotNullJavaSubtype {
 
     public interface Sub : test.AddNotNullJavaSubtype.Super {
         public abstract override /*1*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        org.jetbrains.annotations.NotNull() public abstract override /*1*/ fun foo(): kotlin.String!
+        org.jetbrains.annotations.NotNull() public abstract override /*1*/ fun foo(): kotlin.String
     }
 
     public interface Super {
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNotNullSameJavaType.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNotNullSameJavaType.txt
index 16c66d601eb..9d15cc371b4 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNotNullSameJavaType.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNotNullSameJavaType.txt
@@ -4,7 +4,7 @@ public interface AddNotNullSameJavaType {
 
     public interface Sub : test.AddNotNullSameJavaType.Super {
         public abstract override /*1*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        org.jetbrains.annotations.NotNull() public abstract override /*1*/ fun foo(): kotlin.CharSequence!
+        org.jetbrains.annotations.NotNull() public abstract override /*1*/ fun foo(): kotlin.CharSequence
     }
 
     public interface Super {
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNullabilityJavaSubtype.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNullabilityJavaSubtype.txt
index 119585dda3e..7f6f5b9f32c 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNullabilityJavaSubtype.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNullabilityJavaSubtype.txt
@@ -4,11 +4,11 @@ public interface AddNullabilityJavaSubtype {
 
     public interface Sub : test.AddNullabilityJavaSubtype.Super {
         public abstract override /*1*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*1*/ fun foo(): kotlin.String!
+        public abstract override /*1*/ fun foo(): kotlin.String
     }
 
     public interface Super {
         public abstract fun dummy(): kotlin.Unit
-        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence!
+        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence
     }
 }
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNullabilitySameJavaType.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNullabilitySameJavaType.txt
index e314b0c1afc..6dfd67de948 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNullabilitySameJavaType.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/AddNullabilitySameJavaType.txt
@@ -4,11 +4,11 @@ public interface AddNullabilitySameJavaType {
 
     public interface Sub : test.AddNullabilitySameJavaType.Super {
         public abstract override /*1*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*1*/ fun foo(): kotlin.CharSequence!
+        public abstract override /*1*/ fun foo(): kotlin.CharSequence
     }
 
     public interface Super {
         public abstract fun dummy(): kotlin.Unit
-        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence!
+        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence
     }
 }
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/InheritNullabilityJavaSubtype.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/InheritNullabilityJavaSubtype.txt
index 3f186405d99..0310ee65635 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/InheritNullabilityJavaSubtype.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/InheritNullabilityJavaSubtype.txt
@@ -4,11 +4,11 @@ public interface InheritNullabilityJavaSubtype {
 
     public interface Sub : test.InheritNullabilityJavaSubtype.Super {
         public abstract override /*1*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*1*/ fun foo(): kotlin.String!
+        public abstract override /*1*/ fun foo(): kotlin.String
     }
 
     public interface Super {
         public abstract fun dummy(): kotlin.Unit
-        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence!
+        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence
     }
 }
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/InheritNullabilitySameJavaType.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/InheritNullabilitySameJavaType.txt
index e0c68dc5b42..06ea5118974 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/InheritNullabilitySameJavaType.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/InheritNullabilitySameJavaType.txt
@@ -4,11 +4,11 @@ public interface InheritNullabilitySameJavaType {
 
     public interface Sub : test.InheritNullabilitySameJavaType.Super {
         public abstract override /*1*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*1*/ fun foo(): kotlin.CharSequence!
+        public abstract override /*1*/ fun foo(): kotlin.CharSequence
     }
 
     public interface Super {
         public abstract fun dummy(): kotlin.Unit
-        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence!
+        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence
     }
 }
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/SubclassOfCollection.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/SubclassOfCollection.txt
index 116c51fa854..4aaff4269d9 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/SubclassOfCollection.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/SubclassOfCollection.txt
@@ -7,7 +7,7 @@ public interface SubclassOfCollection</*0*/ E> : kotlin.MutableCollection<E!> {
     public abstract override /*1*/ /*fake_override*/ fun contains(/*0*/ o: kotlin.Any?): kotlin.Boolean
     public abstract override /*1*/ /*fake_override*/ fun containsAll(/*0*/ c: kotlin.Collection<kotlin.Any?>): kotlin.Boolean
     public abstract override /*1*/ /*fake_override*/ fun isEmpty(): kotlin.Boolean
-    public abstract override /*1*/ fun iterator(): kotlin.(Mutable)Iterator<E!>!
+    public abstract override /*1*/ fun iterator(): kotlin.MutableIterator<E!>
     public abstract override /*1*/ /*fake_override*/ fun remove(/*0*/ o: kotlin.Any?): kotlin.Boolean
     public abstract override /*1*/ /*fake_override*/ fun removeAll(/*0*/ c: kotlin.Collection<kotlin.Any?>): kotlin.Boolean
     public abstract override /*1*/ /*fake_override*/ fun retainAll(/*0*/ c: kotlin.Collection<kotlin.Any?>): kotlin.Boolean
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/TwoSuperclassesReturnJavaSubtype.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/TwoSuperclassesReturnJavaSubtype.txt
index 23c06c4bd70..c306b3311f4 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/TwoSuperclassesReturnJavaSubtype.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/TwoSuperclassesReturnJavaSubtype.txt
@@ -4,7 +4,7 @@ public interface TwoSuperclassesReturnJavaSubtype {
 
     public interface Sub : test.TwoSuperclassesReturnJavaSubtype.Super1, test.TwoSuperclassesReturnJavaSubtype.Super2 {
         public abstract override /*2*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*2*/ fun foo(): kotlin.String!
+        public abstract override /*2*/ fun foo(): kotlin.String
     }
 
     public interface Super1 {
@@ -14,6 +14,6 @@ public interface TwoSuperclassesReturnJavaSubtype {
 
     public interface Super2 {
         public abstract fun dummy(): kotlin.Unit
-        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence!
+        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence
     }
 }
diff --git a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/TwoSuperclassesReturnSameJavaType.txt b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/TwoSuperclassesReturnSameJavaType.txt
index 635d8a77bd9..792b870788a 100644
--- a/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/TwoSuperclassesReturnSameJavaType.txt
+++ b/compiler/testData/loadJava/compiledJava/kotlinSignature/propagation/return/TwoSuperclassesReturnSameJavaType.txt
@@ -4,7 +4,7 @@ public interface TwoSuperclassesReturnSameJavaType {
 
     public interface Sub : test.TwoSuperclassesReturnSameJavaType.Super1, test.TwoSuperclassesReturnSameJavaType.Super2 {
         public abstract override /*2*/ /*fake_override*/ fun dummy(): kotlin.Unit
-        public abstract override /*2*/ fun foo(): kotlin.CharSequence!
+        public abstract override /*2*/ fun foo(): kotlin.CharSequence
     }
 
     public interface Super1 {
@@ -14,6 +14,6 @@ public interface TwoSuperclassesReturnSameJavaType {
 
     public interface Super2 {
         public abstract fun dummy(): kotlin.Unit
-        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence!
+        org.jetbrains.annotations.NotNull() public abstract fun foo(): kotlin.CharSequence
     }
 }
diff --git a/compiler/testData/loadJava/compiledJava/modality/ModalityOfFakeOverrides.txt b/compiler/testData/loadJava/compiledJava/modality/ModalityOfFakeOverrides.txt
index 0252161588b..310024e6e0b 100644
--- a/compiler/testData/loadJava/compiledJava/modality/ModalityOfFakeOverrides.txt
+++ b/compiler/testData/loadJava/compiledJava/modality/ModalityOfFakeOverrides.txt
@@ -6,17 +6,17 @@ public open class ModalityOfFakeOverrides : java.util.AbstractList<kotlin.String
     public open override /*1*/ /*fake_override*/ fun add(/*0*/ index: kotlin.Int, /*1*/ element: kotlin.String!): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun add(/*0*/ e: kotlin.String!): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ c: kotlin.Collection<kotlin.String!>): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ index: kotlin.Int, /*1*/ c: (kotlin.MutableCollection<out kotlin.String!>..kotlin.Collection<kotlin.String!>?)): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ index: kotlin.Int, /*1*/ c: kotlin.Collection<kotlin.String!>): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun clear(): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun contains(/*0*/ o: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun containsAll(/*0*/ c: kotlin.Collection<kotlin.Any?>): kotlin.Boolean
-    org.jetbrains.annotations.NotNull() public open override /*1*/ fun get(/*0*/ index: kotlin.Int): kotlin.String!
-    public open override /*1*/ /*fake_override*/ fun indexOf(/*0*/ o: kotlin.Any!): kotlin.Int
+    org.jetbrains.annotations.NotNull() public open override /*1*/ fun get(/*0*/ index: kotlin.Int): kotlin.String
+    public open override /*1*/ /*fake_override*/ fun indexOf(/*0*/ o: kotlin.Any?): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun isEmpty(): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun iterator(): kotlin.(Mutable)Iterator<kotlin.String!>!
-    public open override /*1*/ /*fake_override*/ fun lastIndexOf(/*0*/ o: kotlin.Any!): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun listIterator(): kotlin.(Mutable)ListIterator<kotlin.String!>!
-    public open override /*1*/ /*fake_override*/ fun listIterator(/*0*/ index: kotlin.Int): kotlin.(Mutable)ListIterator<kotlin.String!>!
+    public open override /*1*/ /*fake_override*/ fun iterator(): kotlin.MutableIterator<kotlin.String!>
+    public open override /*1*/ /*fake_override*/ fun lastIndexOf(/*0*/ o: kotlin.Any?): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun listIterator(): kotlin.MutableListIterator<kotlin.String!>
+    public open override /*1*/ /*fake_override*/ fun listIterator(/*0*/ index: kotlin.Int): kotlin.MutableListIterator<kotlin.String!>
     invisible_fake open override /*1*/ /*fake_override*/ fun outOfBoundsMsg(/*0*/ p0: kotlin.Int): kotlin.String!
     invisible_fake open override /*1*/ /*fake_override*/ fun rangeCheckForAdd(/*0*/ p0: kotlin.Int): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun remove(/*0*/ o: kotlin.Any?): kotlin.Boolean
@@ -26,7 +26,7 @@ public open class ModalityOfFakeOverrides : java.util.AbstractList<kotlin.String
     public open override /*1*/ /*fake_override*/ fun retainAll(/*0*/ c: kotlin.Collection<kotlin.Any?>): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun set(/*0*/ index: kotlin.Int, /*1*/ element: kotlin.String!): kotlin.String!
     public open override /*1*/ fun size(): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun subList(/*0*/ fromIndex: kotlin.Int, /*1*/ toIndex: kotlin.Int): kotlin.(Mutable)List<kotlin.String!>!
+    public open override /*1*/ /*fake_override*/ fun subList(/*0*/ fromIndex: kotlin.Int, /*1*/ toIndex: kotlin.Int): kotlin.MutableList<kotlin.String!>
     public open override /*1*/ /*fake_override*/ fun toArray(): kotlin.Array<(out) kotlin.Any!>!
     public open override /*1*/ /*fake_override*/ fun </*0*/ T> toArray(/*0*/ p0: kotlin.Array<(out) T!>!): kotlin.Array<(out) T!>!
 }
diff --git a/compiler/testData/loadJava/compiledJava/mutability/LoadIterable.txt b/compiler/testData/loadJava/compiledJava/mutability/LoadIterable.txt
index c380b33c65b..36940f5e657 100644
--- a/compiler/testData/loadJava/compiledJava/mutability/LoadIterable.txt
+++ b/compiler/testData/loadJava/compiledJava/mutability/LoadIterable.txt
@@ -1,8 +1,8 @@
 package test
 
 public interface LoadIterable</*0*/ T> {
-    org.jetbrains.annotations.Mutable() public abstract fun getIterable(): kotlin.(Mutable)Iterable<T!>!
-    org.jetbrains.annotations.ReadOnly() public abstract fun getReadOnlyIterable(): kotlin.(Mutable)Iterable<T!>!
-    public abstract fun setIterable(/*0*/ org.jetbrains.annotations.Mutable() p0: kotlin.(Mutable)Iterable<T!>!): kotlin.Unit
-    public abstract fun setReadOnlyIterable(/*0*/ org.jetbrains.annotations.ReadOnly() p0: kotlin.(Mutable)Iterable<T!>!): kotlin.Unit
+    org.jetbrains.annotations.Mutable() public abstract fun getIterable(): kotlin.MutableIterable<T!>!
+    org.jetbrains.annotations.ReadOnly() public abstract fun getReadOnlyIterable(): kotlin.Iterable<T!>!
+    public abstract fun setIterable(/*0*/ org.jetbrains.annotations.Mutable() p0: kotlin.MutableIterable<T!>!): kotlin.Unit
+    public abstract fun setReadOnlyIterable(/*0*/ org.jetbrains.annotations.ReadOnly() p0: kotlin.Iterable<T!>!): kotlin.Unit
 }
diff --git a/compiler/testData/loadJava/compiledJava/mutability/LoadIterableWithNullability.txt b/compiler/testData/loadJava/compiledJava/mutability/LoadIterableWithNullability.txt
index 486bea8b4fd..f100a0859c1 100644
--- a/compiler/testData/loadJava/compiledJava/mutability/LoadIterableWithNullability.txt
+++ b/compiler/testData/loadJava/compiledJava/mutability/LoadIterableWithNullability.txt
@@ -1,8 +1,8 @@
 package test
 
 public interface LoadIterableWithNullability</*0*/ T> {
-    org.jetbrains.annotations.NotNull() org.jetbrains.annotations.Mutable() public abstract fun getIterable(): kotlin.(Mutable)Iterable<T!>!
-    org.jetbrains.annotations.NotNull() org.jetbrains.annotations.ReadOnly() public abstract fun getReadOnlyIterable(): kotlin.(Mutable)Iterable<T!>!
-    public abstract fun setIterable(/*0*/ org.jetbrains.annotations.Mutable() org.jetbrains.annotations.NotNull() p0: kotlin.(Mutable)Iterable<T!>!): kotlin.Unit
-    public abstract fun setReadOnlyIterable(/*0*/ org.jetbrains.annotations.ReadOnly() org.jetbrains.annotations.NotNull() p0: kotlin.(Mutable)Iterable<T!>!): kotlin.Unit
+    org.jetbrains.annotations.NotNull() org.jetbrains.annotations.Mutable() public abstract fun getIterable(): kotlin.MutableIterable<T!>
+    org.jetbrains.annotations.NotNull() org.jetbrains.annotations.ReadOnly() public abstract fun getReadOnlyIterable(): kotlin.Iterable<T!>
+    public abstract fun setIterable(/*0*/ org.jetbrains.annotations.Mutable() org.jetbrains.annotations.NotNull() p0: kotlin.MutableIterable<T!>): kotlin.Unit
+    public abstract fun setReadOnlyIterable(/*0*/ org.jetbrains.annotations.ReadOnly() org.jetbrains.annotations.NotNull() p0: kotlin.Iterable<T!>): kotlin.Unit
 }
diff --git a/compiler/testData/loadJava/compiledJava/mutability/LoadIterableWithPropagation.txt b/compiler/testData/loadJava/compiledJava/mutability/LoadIterableWithPropagation.txt
index 3e9b39c46d8..b60f86b8058 100644
--- a/compiler/testData/loadJava/compiledJava/mutability/LoadIterableWithPropagation.txt
+++ b/compiler/testData/loadJava/compiledJava/mutability/LoadIterableWithPropagation.txt
@@ -3,17 +3,17 @@ package test
 public interface LoadIterableWithPropagation {
 
     public interface LoadIterable</*0*/ T> {
-        org.jetbrains.annotations.Mutable() public abstract fun getIterable(): kotlin.(Mutable)Iterable<T!>!
-        org.jetbrains.annotations.ReadOnly() public abstract fun getReadOnlyIterable(): kotlin.(Mutable)Iterable<T!>!
-        public abstract fun setIterable(/*0*/ org.jetbrains.annotations.Mutable() p0: kotlin.(Mutable)Iterable<T!>!): kotlin.Unit
-        public abstract fun setReadOnlyIterable(/*0*/ org.jetbrains.annotations.ReadOnly() p0: kotlin.(Mutable)Iterable<T!>!): kotlin.Unit
+        org.jetbrains.annotations.Mutable() public abstract fun getIterable(): kotlin.MutableIterable<T!>!
+        org.jetbrains.annotations.ReadOnly() public abstract fun getReadOnlyIterable(): kotlin.Iterable<T!>!
+        public abstract fun setIterable(/*0*/ org.jetbrains.annotations.Mutable() p0: kotlin.MutableIterable<T!>!): kotlin.Unit
+        public abstract fun setReadOnlyIterable(/*0*/ org.jetbrains.annotations.ReadOnly() p0: kotlin.Iterable<T!>!): kotlin.Unit
     }
 
     public open class LoadIterableImpl</*0*/ T> : test.LoadIterableWithPropagation.LoadIterable<T!> {
         public constructor LoadIterableImpl</*0*/ T>()
-        public open override /*1*/ fun getIterable(): kotlin.(Mutable)Iterable<T!>!
-        public open override /*1*/ fun getReadOnlyIterable(): kotlin.(Mutable)Iterable<T!>!
-        public open override /*1*/ fun setIterable(/*0*/ p0: kotlin.(Mutable)Iterable<T!>!): kotlin.Unit
-        public open override /*1*/ fun setReadOnlyIterable(/*0*/ p0: kotlin.(Mutable)Iterable<T!>!): kotlin.Unit
+        public open override /*1*/ fun getIterable(): kotlin.MutableIterable<T!>!
+        public open override /*1*/ fun getReadOnlyIterable(): kotlin.Iterable<T!>!
+        public open override /*1*/ fun setIterable(/*0*/ p0: kotlin.MutableIterable<T!>!): kotlin.Unit
+        public open override /*1*/ fun setReadOnlyIterable(/*0*/ p0: kotlin.Iterable<T!>!): kotlin.Unit
     }
 }
diff --git a/compiler/testData/loadJava/compiledJava/notNull/NotNullIntArray.txt b/compiler/testData/loadJava/compiledJava/notNull/NotNullIntArray.txt
index d755f202faa..c658fa481d0 100644
--- a/compiler/testData/loadJava/compiledJava/notNull/NotNullIntArray.txt
+++ b/compiler/testData/loadJava/compiledJava/notNull/NotNullIntArray.txt
@@ -2,5 +2,5 @@ package test
 
 public open class NotNullIntArray {
     public constructor NotNullIntArray()
-    org.jetbrains.annotations.NotNull() public open fun hi(): kotlin.IntArray!
+    org.jetbrains.annotations.NotNull() public open fun hi(): kotlin.IntArray
 }
diff --git a/compiler/testData/loadJava/compiledJava/notNull/NotNullMethod.txt b/compiler/testData/loadJava/compiledJava/notNull/NotNullMethod.txt
index 156a9fe5391..0c30b0c6f59 100644
--- a/compiler/testData/loadJava/compiledJava/notNull/NotNullMethod.txt
+++ b/compiler/testData/loadJava/compiledJava/notNull/NotNullMethod.txt
@@ -2,5 +2,5 @@ package test
 
 public open class NotNullMethod {
     public constructor NotNullMethod()
-    org.jetbrains.annotations.NotNull() public open fun hi(): kotlin.String!
+    org.jetbrains.annotations.NotNull() public open fun hi(): kotlin.String
 }
diff --git a/compiler/testData/loadJava/compiledJava/notNull/NotNullObjectArray.txt b/compiler/testData/loadJava/compiledJava/notNull/NotNullObjectArray.txt
index d96514dc9ec..01ce03723aa 100644
--- a/compiler/testData/loadJava/compiledJava/notNull/NotNullObjectArray.txt
+++ b/compiler/testData/loadJava/compiledJava/notNull/NotNullObjectArray.txt
@@ -2,5 +2,5 @@ package test
 
 public open class NotNullObjectArray {
     public constructor NotNullObjectArray()
-    org.jetbrains.annotations.NotNull() public open fun hi(): kotlin.Array<(out) kotlin.Any!>!
+    org.jetbrains.annotations.NotNull() public open fun hi(): kotlin.Array<(out) kotlin.Any!>
 }
diff --git a/compiler/testData/loadJava/compiledJava/notNull/NotNullParameter.txt b/compiler/testData/loadJava/compiledJava/notNull/NotNullParameter.txt
index 9cb03cf421f..06636c18c82 100644
--- a/compiler/testData/loadJava/compiledJava/notNull/NotNullParameter.txt
+++ b/compiler/testData/loadJava/compiledJava/notNull/NotNullParameter.txt
@@ -2,5 +2,5 @@ package test
 
 public open class NotNullParameter {
     public constructor NotNullParameter()
-    public open fun hi(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String!): kotlin.Unit
+    public open fun hi(/*0*/ org.jetbrains.annotations.NotNull() p0: kotlin.String): kotlin.Unit
 }
diff --git a/compiler/testData/loadJava/compiledJava/sam/adapters/inheritance/InheritedOverriddenAdapter.txt b/compiler/testData/loadJava/compiledJava/sam/adapters/inheritance/InheritedOverriddenAdapter.txt
index 12bc206e50e..802355c6bf4 100644
--- a/compiler/testData/loadJava/compiledJava/sam/adapters/inheritance/InheritedOverriddenAdapter.txt
+++ b/compiler/testData/loadJava/compiledJava/sam/adapters/inheritance/InheritedOverriddenAdapter.txt
@@ -4,7 +4,7 @@ public interface InheritedOverriddenAdapter {
 
     public open class Sub : test.InheritedOverriddenAdapter.Super {
         public constructor Sub()
-        public open override /*1*/ fun foo(/*0*/ p0: (() -> kotlin.Unit!)!): kotlin.Unit
+        public open override /*1*/ fun foo(/*0*/ p0: (() -> kotlin.Unit)!): kotlin.Unit
         public open override /*1*/ /*fake_override*/ fun foo(/*0*/ p0: java.lang.Runnable!): kotlin.Unit
     }
 
diff --git a/compiler/testData/loadJava/compiledJava/sam/adapters/inheritance/OverriddenAmbiguousAdapters.txt b/compiler/testData/loadJava/compiledJava/sam/adapters/inheritance/OverriddenAmbiguousAdapters.txt
index 3c14e209a7f..376b3ef7589 100644
--- a/compiler/testData/loadJava/compiledJava/sam/adapters/inheritance/OverriddenAmbiguousAdapters.txt
+++ b/compiler/testData/loadJava/compiledJava/sam/adapters/inheritance/OverriddenAmbiguousAdapters.txt
@@ -3,7 +3,7 @@ package test
 public interface OverriddenAmbiguousAdapters {
 
     public interface Sub : test.OverriddenAmbiguousAdapters.Super {
-        public abstract override /*2*/ fun foo(/*0*/ p0: (() -> kotlin.Unit!)!): kotlin.Unit
+        public abstract override /*2*/ fun foo(/*0*/ p0: (() -> kotlin.Unit)!): kotlin.Unit
         public abstract override /*1*/ /*fake_override*/ fun foo(/*0*/ p0: java.io.Closeable!): kotlin.Unit
         public abstract override /*1*/ /*fake_override*/ fun foo(/*0*/ p0: java.lang.Runnable!): kotlin.Unit
     }
diff --git a/compiler/testData/loadJava/compiledJava/signaturePropagation/RawSuperType.txt b/compiler/testData/loadJava/compiledJava/signaturePropagation/RawSuperType.txt
index d8aecadb676..302b5090c63 100644
--- a/compiler/testData/loadJava/compiledJava/signaturePropagation/RawSuperType.txt
+++ b/compiler/testData/loadJava/compiledJava/signaturePropagation/RawSuperType.txt
@@ -6,7 +6,7 @@ public open class RawSuperType {
     public open inner class Derived : test.RawSuperType.Super<kotlin.Any?> {
         public constructor Derived()
         public open override /*1*/ fun dummy(): kotlin.Unit
-        public open override /*1*/ fun foo(/*0*/ p0: kotlin.Any!): kotlin.Unit
+        public open override /*1*/ fun foo(/*0*/ p0: kotlin.Any?): kotlin.Unit
     }
 
     public interface Super</*0*/ T> {
diff --git a/compiler/testData/loadJava/compiledJava/signaturePropagation/RawSuperTypeWithRecursiveBoundMultipleParameters.txt b/compiler/testData/loadJava/compiledJava/signaturePropagation/RawSuperTypeWithRecursiveBoundMultipleParameters.txt
index f19f6f76e92..b6d22fba192 100644
--- a/compiler/testData/loadJava/compiledJava/signaturePropagation/RawSuperTypeWithRecursiveBoundMultipleParameters.txt
+++ b/compiler/testData/loadJava/compiledJava/signaturePropagation/RawSuperTypeWithRecursiveBoundMultipleParameters.txt
@@ -7,7 +7,7 @@ public open class RawSuperTypeWithRecursiveBoundMultipleParameters {
         public constructor Derived()
         public open override /*1*/ fun dummy(): kotlin.Unit
         public open fun foo(/*0*/ p0: kotlin.Any!, /*1*/ p1: kotlin.Any!): kotlin.Unit
-        public open override /*1*/ fun foo(/*0*/ p0: kotlin.Any!, /*1*/ p1: test.RawSuperTypeWithRecursiveBoundMultipleParameters.Super<*, *>!): kotlin.Unit
+        public open override /*1*/ fun foo(/*0*/ p0: kotlin.Any?, /*1*/ p1: test.RawSuperTypeWithRecursiveBoundMultipleParameters.Super<*, *>!): kotlin.Unit
     }
 
     public interface Super</*0*/ R, /*1*/ T : test.RawSuperTypeWithRecursiveBoundMultipleParameters.Super<R!, T!>!> {
diff --git a/compiler/testData/loadJava/compiledJavaIncludeObjectMethods/ClassWithObjectMethod.txt b/compiler/testData/loadJava/compiledJavaIncludeObjectMethods/ClassWithObjectMethod.txt
index 96ba443f37e..d83e51668c1 100644
--- a/compiler/testData/loadJava/compiledJavaIncludeObjectMethods/ClassWithObjectMethod.txt
+++ b/compiler/testData/loadJava/compiledJavaIncludeObjectMethods/ClassWithObjectMethod.txt
@@ -4,5 +4,5 @@ public final class ClassWithObjectMethod {
     public constructor ClassWithObjectMethod()
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ fun toString(): kotlin.String!
+    public open override /*1*/ fun toString(): kotlin.String
 }
diff --git a/compiler/testData/loadJava/compiledKotlin/fromLoadJava/ClassDoesNotOverrideMethod.txt b/compiler/testData/loadJava/compiledKotlin/fromLoadJava/ClassDoesNotOverrideMethod.txt
index 436e31f8308..6def49899eb 100644
--- a/compiler/testData/loadJava/compiledKotlin/fromLoadJava/ClassDoesNotOverrideMethod.txt
+++ b/compiler/testData/loadJava/compiledKotlin/fromLoadJava/ClassDoesNotOverrideMethod.txt
@@ -6,7 +6,7 @@ public abstract class ClassDoesNotOverrideMethod : java.util.Date {
     invisible_fake final override /*1*/ /*fake_override*/ var fastTime: kotlin.Long
     public open override /*1*/ /*fake_override*/ fun after(/*0*/ p0: java.util.Date!): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun before(/*0*/ p0: java.util.Date!): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun clone(): kotlin.Any!
+    public open override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
     public open override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: java.util.Date!): kotlin.Int
     invisible_fake final override /*1*/ /*fake_override*/ fun getCalendarDate(): sun.util.calendar.BaseCalendar.Date!
     kotlin.deprecated(value = "Deprecated in Java") public open override /*1*/ /*fake_override*/ fun getDate(): kotlin.Int
diff --git a/compiler/testData/loadJava/compiledKotlin/fromLoadJava/modality/ModalityOfFakeOverrides.txt b/compiler/testData/loadJava/compiledKotlin/fromLoadJava/modality/ModalityOfFakeOverrides.txt
index 909ff1c844a..18cd766a66d 100644
--- a/compiler/testData/loadJava/compiledKotlin/fromLoadJava/modality/ModalityOfFakeOverrides.txt
+++ b/compiler/testData/loadJava/compiledKotlin/fromLoadJava/modality/ModalityOfFakeOverrides.txt
@@ -6,17 +6,17 @@ public open class ModalityOfFakeOverrides : java.util.AbstractList<kotlin.String
     public open override /*1*/ /*fake_override*/ fun add(/*0*/ index: kotlin.Int, /*1*/ element: kotlin.String!): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun add(/*0*/ e: kotlin.String!): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ c: kotlin.Collection<kotlin.String!>): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ index: kotlin.Int, /*1*/ c: (kotlin.MutableCollection<out kotlin.String!>..kotlin.Collection<kotlin.String!>?)): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ index: kotlin.Int, /*1*/ c: kotlin.Collection<kotlin.String!>): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun clear(): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun contains(/*0*/ o: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun containsAll(/*0*/ c: kotlin.Collection<kotlin.Any?>): kotlin.Boolean
     public open override /*1*/ fun get(/*0*/ index: kotlin.Int): kotlin.String
-    public open override /*1*/ /*fake_override*/ fun indexOf(/*0*/ o: kotlin.Any!): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun indexOf(/*0*/ o: kotlin.Any?): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun isEmpty(): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun iterator(): kotlin.(Mutable)Iterator<kotlin.String!>!
-    public open override /*1*/ /*fake_override*/ fun lastIndexOf(/*0*/ o: kotlin.Any!): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun listIterator(): kotlin.(Mutable)ListIterator<kotlin.String!>!
-    public open override /*1*/ /*fake_override*/ fun listIterator(/*0*/ index: kotlin.Int): kotlin.(Mutable)ListIterator<kotlin.String!>!
+    public open override /*1*/ /*fake_override*/ fun iterator(): kotlin.MutableIterator<kotlin.String!>
+    public open override /*1*/ /*fake_override*/ fun lastIndexOf(/*0*/ o: kotlin.Any?): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun listIterator(): kotlin.MutableListIterator<kotlin.String!>
+    public open override /*1*/ /*fake_override*/ fun listIterator(/*0*/ index: kotlin.Int): kotlin.MutableListIterator<kotlin.String!>
     invisible_fake open override /*1*/ /*fake_override*/ fun outOfBoundsMsg(/*0*/ p0: kotlin.Int): kotlin.String!
     invisible_fake open override /*1*/ /*fake_override*/ fun rangeCheckForAdd(/*0*/ p0: kotlin.Int): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun remove(/*0*/ o: kotlin.Any?): kotlin.Boolean
@@ -26,7 +26,7 @@ public open class ModalityOfFakeOverrides : java.util.AbstractList<kotlin.String
     public open override /*1*/ /*fake_override*/ fun retainAll(/*0*/ c: kotlin.Collection<kotlin.Any?>): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun set(/*0*/ index: kotlin.Int, /*1*/ element: kotlin.String!): kotlin.String!
     public open override /*1*/ fun size(): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun subList(/*0*/ fromIndex: kotlin.Int, /*1*/ toIndex: kotlin.Int): kotlin.(Mutable)List<kotlin.String!>!
+    public open override /*1*/ /*fake_override*/ fun subList(/*0*/ fromIndex: kotlin.Int, /*1*/ toIndex: kotlin.Int): kotlin.MutableList<kotlin.String!>
     public open override /*1*/ /*fake_override*/ fun toArray(): kotlin.Array<(out) kotlin.Any!>!
     public open override /*1*/ /*fake_override*/ fun </*0*/ T> toArray(/*0*/ p0: kotlin.Array<(out) T!>!): kotlin.Array<(out) T!>!
 }
diff --git a/compiler/testData/loadJava/compiledKotlin/platformTypes/notnullTypeArgument.txt b/compiler/testData/loadJava/compiledKotlin/platformTypes/notnullTypeArgument.txt
index f141b72352f..02eb0d439c2 100644
--- a/compiler/testData/loadJava/compiledKotlin/platformTypes/notnullTypeArgument.txt
+++ b/compiler/testData/loadJava/compiledKotlin/platformTypes/notnullTypeArgument.txt
@@ -7,12 +7,12 @@ internal final class C : java.util.ArrayList<kotlin.String> {
     invisible_fake final override /*1*/ /*fake_override*/ var size: kotlin.Int
     public open override /*1*/ /*fake_override*/ fun add(/*0*/ index: kotlin.Int, /*1*/ element: kotlin.String!): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun add(/*0*/ e: kotlin.String!): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ c: (kotlin.MutableCollection<out kotlin.String!>..kotlin.Collection<kotlin.String!>?)): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ index: kotlin.Int, /*1*/ c: (kotlin.MutableCollection<out kotlin.String!>..kotlin.Collection<kotlin.String!>?)): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ c: kotlin.Collection<kotlin.String!>): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ index: kotlin.Int, /*1*/ c: kotlin.Collection<kotlin.String!>): kotlin.Boolean
     invisible_fake open override /*1*/ /*fake_override*/ fun batchRemove(/*0*/ p0: kotlin.(Mutable)Collection<*>!, /*1*/ p1: kotlin.Boolean): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun clear(): kotlin.Unit
-    public open override /*1*/ /*fake_override*/ fun clone(): kotlin.Any!
-    public open override /*1*/ /*fake_override*/ fun contains(/*0*/ o: kotlin.Any!): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
+    public open override /*1*/ /*fake_override*/ fun contains(/*0*/ o: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun containsAll(/*0*/ c: kotlin.Collection<kotlin.Any?>): kotlin.Boolean
     invisible_fake open override /*1*/ /*fake_override*/ fun elementData(/*0*/ p0: kotlin.Int): kotlin.String!
     public open override /*1*/ /*fake_override*/ fun ensureCapacity(/*0*/ p0: kotlin.Int): kotlin.Unit
@@ -20,24 +20,24 @@ internal final class C : java.util.ArrayList<kotlin.String> {
     invisible_fake open override /*1*/ /*fake_override*/ fun fastRemove(/*0*/ p0: kotlin.Int): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun get(/*0*/ index: kotlin.Int): kotlin.String!
     invisible_fake open override /*1*/ /*fake_override*/ fun grow(/*0*/ p0: kotlin.Int): kotlin.Unit
-    public open override /*1*/ /*fake_override*/ fun indexOf(/*0*/ o: kotlin.Any!): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun indexOf(/*0*/ o: kotlin.Any?): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun isEmpty(): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun iterator(): kotlin.(Mutable)Iterator<kotlin.String!>!
-    public open override /*1*/ /*fake_override*/ fun lastIndexOf(/*0*/ o: kotlin.Any!): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun listIterator(): kotlin.(Mutable)ListIterator<kotlin.String!>!
-    public open override /*1*/ /*fake_override*/ fun listIterator(/*0*/ index: kotlin.Int): kotlin.(Mutable)ListIterator<kotlin.String!>!
+    public open override /*1*/ /*fake_override*/ fun iterator(): kotlin.MutableIterator<kotlin.String!>
+    public open override /*1*/ /*fake_override*/ fun lastIndexOf(/*0*/ o: kotlin.Any?): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun listIterator(): kotlin.MutableListIterator<kotlin.String!>
+    public open override /*1*/ /*fake_override*/ fun listIterator(/*0*/ index: kotlin.Int): kotlin.MutableListIterator<kotlin.String!>
     invisible_fake open override /*1*/ /*fake_override*/ fun outOfBoundsMsg(/*0*/ p0: kotlin.Int): kotlin.String!
     invisible_fake open override /*1*/ /*fake_override*/ fun rangeCheck(/*0*/ p0: kotlin.Int): kotlin.Unit
     invisible_fake open override /*1*/ /*fake_override*/ fun rangeCheckForAdd(/*0*/ p0: kotlin.Int): kotlin.Unit
     invisible_fake open override /*1*/ /*fake_override*/ fun readObject(/*0*/ p0: java.io.ObjectInputStream!): kotlin.Unit
-    public open override /*1*/ /*fake_override*/ fun remove(/*0*/ o: kotlin.Any!): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun remove(/*0*/ o: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun remove(/*0*/ index: kotlin.Int): kotlin.String!
-    public open override /*1*/ /*fake_override*/ fun removeAll(/*0*/ c: kotlin.(Mutable)Collection<*>!): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun removeAll(/*0*/ c: kotlin.Collection<*>): kotlin.Boolean
     protected/*protected and package*/ open override /*1*/ /*fake_override*/ fun removeRange(/*0*/ p0: kotlin.Int, /*1*/ p1: kotlin.Int): kotlin.Unit
-    public open override /*1*/ /*fake_override*/ fun retainAll(/*0*/ c: kotlin.(Mutable)Collection<*>!): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun retainAll(/*0*/ c: kotlin.Collection<*>): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun set(/*0*/ index: kotlin.Int, /*1*/ element: kotlin.String!): kotlin.String!
     public open override /*1*/ /*fake_override*/ fun size(): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun subList(/*0*/ fromIndex: kotlin.Int, /*1*/ toIndex: kotlin.Int): kotlin.(Mutable)List<kotlin.String!>!
+    public open override /*1*/ /*fake_override*/ fun subList(/*0*/ fromIndex: kotlin.Int, /*1*/ toIndex: kotlin.Int): kotlin.MutableList<kotlin.String!>
     public open override /*1*/ /*fake_override*/ fun toArray(): kotlin.Array<(out) kotlin.Any!>!
     public open override /*1*/ /*fake_override*/ fun </*0*/ T> toArray(/*0*/ p0: kotlin.Array<(out) T!>!): kotlin.Array<(out) T!>!
     public open override /*1*/ /*fake_override*/ fun trimToSize(): kotlin.Unit
diff --git a/compiler/testData/loadJava/compiledKotlin/platformTypes/nullableTypeArgument.txt b/compiler/testData/loadJava/compiledKotlin/platformTypes/nullableTypeArgument.txt
index 74a2a4542fa..d2b6a1ba643 100644
--- a/compiler/testData/loadJava/compiledKotlin/platformTypes/nullableTypeArgument.txt
+++ b/compiler/testData/loadJava/compiledKotlin/platformTypes/nullableTypeArgument.txt
@@ -7,12 +7,12 @@ internal final class C : java.util.ArrayList<kotlin.String?> {
     invisible_fake final override /*1*/ /*fake_override*/ var size: kotlin.Int
     public open override /*1*/ /*fake_override*/ fun add(/*0*/ index: kotlin.Int, /*1*/ element: kotlin.String?): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun add(/*0*/ e: kotlin.String?): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ c: (kotlin.MutableCollection<out kotlin.String?>..kotlin.Collection<kotlin.String?>?)): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ index: kotlin.Int, /*1*/ c: (kotlin.MutableCollection<out kotlin.String?>..kotlin.Collection<kotlin.String?>?)): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ c: kotlin.Collection<kotlin.String?>): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun addAll(/*0*/ index: kotlin.Int, /*1*/ c: kotlin.Collection<kotlin.String?>): kotlin.Boolean
     invisible_fake open override /*1*/ /*fake_override*/ fun batchRemove(/*0*/ p0: kotlin.(Mutable)Collection<*>!, /*1*/ p1: kotlin.Boolean): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun clear(): kotlin.Unit
-    public open override /*1*/ /*fake_override*/ fun clone(): kotlin.Any!
-    public open override /*1*/ /*fake_override*/ fun contains(/*0*/ o: kotlin.Any!): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun clone(): kotlin.Any
+    public open override /*1*/ /*fake_override*/ fun contains(/*0*/ o: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun containsAll(/*0*/ c: kotlin.Collection<kotlin.Any?>): kotlin.Boolean
     invisible_fake open override /*1*/ /*fake_override*/ fun elementData(/*0*/ p0: kotlin.Int): kotlin.String?
     public open override /*1*/ /*fake_override*/ fun ensureCapacity(/*0*/ p0: kotlin.Int): kotlin.Unit
@@ -20,24 +20,24 @@ internal final class C : java.util.ArrayList<kotlin.String?> {
     invisible_fake open override /*1*/ /*fake_override*/ fun fastRemove(/*0*/ p0: kotlin.Int): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun get(/*0*/ index: kotlin.Int): kotlin.String?
     invisible_fake open override /*1*/ /*fake_override*/ fun grow(/*0*/ p0: kotlin.Int): kotlin.Unit
-    public open override /*1*/ /*fake_override*/ fun indexOf(/*0*/ o: kotlin.Any!): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun indexOf(/*0*/ o: kotlin.Any?): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun isEmpty(): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun iterator(): kotlin.(Mutable)Iterator<kotlin.String?>!
-    public open override /*1*/ /*fake_override*/ fun lastIndexOf(/*0*/ o: kotlin.Any!): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun listIterator(): kotlin.(Mutable)ListIterator<kotlin.String?>!
-    public open override /*1*/ /*fake_override*/ fun listIterator(/*0*/ index: kotlin.Int): kotlin.(Mutable)ListIterator<kotlin.String?>!
+    public open override /*1*/ /*fake_override*/ fun iterator(): kotlin.MutableIterator<kotlin.String?>
+    public open override /*1*/ /*fake_override*/ fun lastIndexOf(/*0*/ o: kotlin.Any?): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun listIterator(): kotlin.MutableListIterator<kotlin.String?>
+    public open override /*1*/ /*fake_override*/ fun listIterator(/*0*/ index: kotlin.Int): kotlin.MutableListIterator<kotlin.String?>
     invisible_fake open override /*1*/ /*fake_override*/ fun outOfBoundsMsg(/*0*/ p0: kotlin.Int): kotlin.String!
     invisible_fake open override /*1*/ /*fake_override*/ fun rangeCheck(/*0*/ p0: kotlin.Int): kotlin.Unit
     invisible_fake open override /*1*/ /*fake_override*/ fun rangeCheckForAdd(/*0*/ p0: kotlin.Int): kotlin.Unit
     invisible_fake open override /*1*/ /*fake_override*/ fun readObject(/*0*/ p0: java.io.ObjectInputStream!): kotlin.Unit
-    public open override /*1*/ /*fake_override*/ fun remove(/*0*/ o: kotlin.Any!): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun remove(/*0*/ o: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun remove(/*0*/ index: kotlin.Int): kotlin.String?
-    public open override /*1*/ /*fake_override*/ fun removeAll(/*0*/ c: kotlin.(Mutable)Collection<*>!): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun removeAll(/*0*/ c: kotlin.Collection<*>): kotlin.Boolean
     protected/*protected and package*/ open override /*1*/ /*fake_override*/ fun removeRange(/*0*/ p0: kotlin.Int, /*1*/ p1: kotlin.Int): kotlin.Unit
-    public open override /*1*/ /*fake_override*/ fun retainAll(/*0*/ c: kotlin.(Mutable)Collection<*>!): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun retainAll(/*0*/ c: kotlin.Collection<*>): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun set(/*0*/ index: kotlin.Int, /*1*/ element: kotlin.String?): kotlin.String?
     public open override /*1*/ /*fake_override*/ fun size(): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun subList(/*0*/ fromIndex: kotlin.Int, /*1*/ toIndex: kotlin.Int): kotlin.(Mutable)List<kotlin.String?>!
+    public open override /*1*/ /*fake_override*/ fun subList(/*0*/ fromIndex: kotlin.Int, /*1*/ toIndex: kotlin.Int): kotlin.MutableList<kotlin.String?>
     public open override /*1*/ /*fake_override*/ fun toArray(): kotlin.Array<(out) kotlin.Any!>!
     public open override /*1*/ /*fake_override*/ fun </*0*/ T> toArray(/*0*/ p0: kotlin.Array<(out) T!>!): kotlin.Array<(out) T!>!
     public open override /*1*/ /*fake_override*/ fun trimToSize(): kotlin.Unit
diff --git a/compiler/testData/loadJava/javaAgainstKotlin/samAdapters/SamAdapterForOverriddenFromKotlin.txt b/compiler/testData/loadJava/javaAgainstKotlin/samAdapters/SamAdapterForOverriddenFromKotlin.txt
index 8d5333eac12..bd1deb09d8e 100644
--- a/compiler/testData/loadJava/javaAgainstKotlin/samAdapters/SamAdapterForOverriddenFromKotlin.txt
+++ b/compiler/testData/loadJava/javaAgainstKotlin/samAdapters/SamAdapterForOverriddenFromKotlin.txt
@@ -3,7 +3,7 @@ package test
 public open class Sub : test.Super {
     public constructor Sub()
     public final /*synthesized*/ fun foo(/*0*/ r: (() -> kotlin.Unit)!): kotlin.Unit
-    public open override /*1*/ fun foo(/*0*/ r: java.lang.Runnable!): kotlin.Unit
+    public open override /*1*/ fun foo(/*0*/ r: java.lang.Runnable): kotlin.Unit
 }
 
 public final class Super {
diff --git a/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/DeepSubclassingKotlinInJava.txt b/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/DeepSubclassingKotlinInJava.txt
index 223dfd90158..8f00c29fcc6 100644
--- a/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/DeepSubclassingKotlinInJava.txt
+++ b/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/DeepSubclassingKotlinInJava.txt
@@ -7,7 +7,7 @@ public open class A {
 
 public open class B : test.A {
     public constructor B()
-    public open override /*1*/ fun foo(): kotlin.String!
+    public open override /*1*/ fun foo(): kotlin.String
 }
 
 public open class C : test.B {
@@ -17,7 +17,7 @@ public open class C : test.B {
 
 public open class D : test.C {
     public constructor D()
-    public open override /*1*/ fun foo(): kotlin.String!
+    public open override /*1*/ fun foo(): kotlin.String
 }
 
 public open class E : test.D {
@@ -27,5 +27,5 @@ public open class E : test.D {
 
 public open class F : test.E {
     public constructor F()
-    public open override /*1*/ fun foo(): kotlin.String!
+    public open override /*1*/ fun foo(): kotlin.String
 }
diff --git a/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/InheritExtensionAndNot.txt b/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/InheritExtensionAndNot.txt
index 517383458fb..b4f71eac63a 100644
--- a/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/InheritExtensionAndNot.txt
+++ b/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/InheritExtensionAndNot.txt
@@ -1,8 +1,8 @@
 package test
 
 public interface Sub : test.Super1, test.Super2 {
-    public abstract override /*1*/ fun bar(/*0*/ vararg p: kotlin.String! /*kotlin.Array<(out) kotlin.String!>!*/): kotlin.Unit
-    public abstract override /*1*/ fun foo(/*0*/ p: kotlin.String!): kotlin.Unit
+    public abstract override /*1*/ fun bar(/*0*/ vararg p: kotlin.String /*kotlin.Array<(out) kotlin.String>*/): kotlin.Unit
+    public abstract override /*1*/ fun foo(/*0*/ p: kotlin.String): kotlin.Unit
     public abstract override /*1*/ /*fake_override*/ fun kotlin.Array<kotlin.String>.bar(): kotlin.Unit
     public abstract override /*1*/ /*fake_override*/ fun kotlin.String.foo(): kotlin.Unit
 }
diff --git a/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/InheritExtensionFunction.txt b/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/InheritExtensionFunction.txt
index b15451c9d0f..aca2de9c103 100644
--- a/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/InheritExtensionFunction.txt
+++ b/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/InheritExtensionFunction.txt
@@ -2,7 +2,7 @@ package test
 
 public open class Sub : test.Super {
     public constructor Sub()
-    public open override /*1*/ fun kotlin.String!.bar(/*0*/ p: kotlin.String!): kotlin.String!
+    public open override /*1*/ fun kotlin.String.bar(/*0*/ p: kotlin.String): kotlin.String
     public final override /*1*/ /*fake_override*/ fun kotlin.String.foo(): kotlin.Unit
 }
 
diff --git a/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/SubclassFromTraitImplementation.txt b/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/SubclassFromTraitImplementation.txt
index b3ea369efd1..af61cb0a0f2 100644
--- a/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/SubclassFromTraitImplementation.txt
+++ b/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/SubclassFromTraitImplementation.txt
@@ -8,7 +8,7 @@ internal open class Impl : test.Trait {
 
 public open class Subclass : test.Impl {
     public constructor Subclass()
-    java.lang.Override() public open override /*1*/ fun bar(): kotlin.String!
+    java.lang.Override() public open override /*1*/ fun bar(): kotlin.String
     internal open override /*1*/ /*fake_override*/ fun foo(): kotlin.String
 }
 
diff --git a/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/SubclassingKotlinInJava.txt b/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/SubclassingKotlinInJava.txt
index d9c07762f24..cd5842fdebe 100644
--- a/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/SubclassingKotlinInJava.txt
+++ b/compiler/testData/loadJava/javaAgainstKotlin/signaturePropagation/SubclassingKotlinInJava.txt
@@ -2,7 +2,7 @@ package test
 
 public open class JavaSubclass : test.KotlinClass {
     public constructor JavaSubclass()
-    public open override /*1*/ fun foo(): kotlin.String!
+    public open override /*1*/ fun foo(): kotlin.String
 }
 
 public open class KotlinClass {
diff --git a/compiler/testData/loadJava/kotlinAgainstCompiledJavaWithKotlin/propagationAgainstDeserializedSuperclass.txt b/compiler/testData/loadJava/kotlinAgainstCompiledJavaWithKotlin/propagationAgainstDeserializedSuperclass.txt
index 980f9346556..8c3668c4786 100644
--- a/compiler/testData/loadJava/kotlinAgainstCompiledJavaWithKotlin/propagationAgainstDeserializedSuperclass.txt
+++ b/compiler/testData/loadJava/kotlinAgainstCompiledJavaWithKotlin/propagationAgainstDeserializedSuperclass.txt
@@ -2,7 +2,7 @@ package test
 
 public open class J : test.K {
     public constructor J()
-    public open override /*1*/ fun foo(/*0*/ l: kotlin.(Mutable)List<kotlin.String!>!): kotlin.String!
+    public open override /*1*/ fun foo(/*0*/ l: kotlin.MutableList<kotlin.String>): kotlin.String
 }
 
 internal interface K {