FIR Java: record Java types with flexible nullability

compiler/fir/analysis-tests/testData/builtIns/kotlin-collections.txt

@@ -1,5 +1,5 @@
 public/*package*/ open class ArraysUtilJVM : R|kotlin/Any| {
-    public/*package*/ open static fun <T : R|ft<kotlin/Any, kotlin/Any?>!|> asList(p0: ):
+    public/*package*/ open static fun <T : R|ft<@FlexibleNullability kotlin/Any, kotlin/Any?>!|> asList(p0: ):
 
     public/*package*/ constructor(): R|kotlin/collections/ArraysUtilJVM|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/NonNullNever.fir.txt

@@ -3,9 +3,9 @@
 
 }
 public open class NonNullNever : R|kotlin/Any| {
-    @R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.NEVER|()) public open field field: R|kotlin/String?|
+    @R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.NEVER|()) public open field field: R|@FlexibleNullability kotlin/String?|
 
-    @R|MyNullable|() public open fun foo(@R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.NEVER|()) x: R|kotlin/String?|, @R|MyNullable|() y: R|kotlin/CharSequence?|): R|kotlin/String?|
+    @R|MyNullable|() public open fun foo(@R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.NEVER|()) x: R|@FlexibleNullability kotlin/String?|, @R|MyNullable|() y: R|@FlexibleNullability kotlin/CharSequence?|): R|@FlexibleNullability kotlin/String?|
 
     public constructor(): R|NonNullNever|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/Simple.fir.txt

@@ -1,7 +1,7 @@
 public open class Simple : R|kotlin/Any| {
-    @R|javax/annotation/Nullable|() public open field field: R|kotlin/String?|
+    @R|javax/annotation/Nullable|() public open field field: R|@FlexibleNullability kotlin/String?|
 
-    @R|javax/annotation/Nullable|() public open fun foo(@R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|kotlin/CharSequence?|): R|kotlin/String?|
+    @R|javax/annotation/Nullable|() public open fun foo(@R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|@FlexibleNullability kotlin/CharSequence?|): R|@FlexibleNullability kotlin/String?|
 
     @R|javax/annotation/Nonnull|() public open fun bar(): R|@EnhancedNullability kotlin/String|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/Strange.fir.txt

@@ -1,7 +1,7 @@
 public open class Strange : R|kotlin/Any| {
-    @R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.UNKNOWN|()) public open field field: R|ft<kotlin/String, kotlin/String?>!|
+    @R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.UNKNOWN|()) public open field field: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
-    @R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.MAYBE|()) public open fun foo(@R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.ALWAYS|()) x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.NEVER|()) y: R|kotlin/CharSequence?|): R|kotlin/String?|
+    @R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.MAYBE|()) public open fun foo(@R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.ALWAYS|()) x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.NEVER|()) y: R|@FlexibleNullability kotlin/CharSequence?|): R|@FlexibleNullability kotlin/String?|
 
     @R|javax/annotation/Nonnull|() public open fun bar(): R|@EnhancedNullability kotlin/String|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/typeQualifierDefault/FieldsAreNullable.fir.txt

@@ -1,9 +1,9 @@
 @R|FieldsAreNullable|() public open class A : R|kotlin/Any| {
-    public open field field: R|kotlin/String?|
+    public open field field: R|@FlexibleNullability kotlin/String?|
 
     @R|javax/annotation/Nonnull|() public open field nonNullField: R|@EnhancedNullability kotlin/String|
 
-    public open fun foo(q: R|ft<kotlin/String, kotlin/String?>!|, @R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|kotlin/CharSequence?|): R|ft<kotlin/String, kotlin/String?>!|
+    public open fun foo(q: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, @R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|@FlexibleNullability kotlin/CharSequence?|): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
     @R|javax/annotation/Nonnull|() public open fun bar(): R|@EnhancedNullability kotlin/String|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/typeQualifierDefault/ForceFlexibility.fir.txt

@@ -1,7 +1,7 @@
 @R|spr/NonNullApi|() public open class A : R|kotlin/Any| {
-    public open fun foo(x: R|kotlin/String|, @R|spr/Nullable|() y: R|kotlin/CharSequence?|): R|kotlin/String|
+    public open fun foo(x: R|@FlexibleNullability kotlin/String|, @R|spr/Nullable|() y: R|@FlexibleNullability kotlin/CharSequence?|): R|@FlexibleNullability kotlin/String|
 
-    @R|spr/ForceFlexibility|() public open fun bar(x: R|ft<kotlin/String, kotlin/String?>!|, @R|javax/annotation/Nonnull|() y: R|@EnhancedNullability kotlin/CharSequence|): R|ft<kotlin/String, kotlin/String?>!|
+    @R|spr/ForceFlexibility|() public open fun bar(x: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, @R|javax/annotation/Nonnull|() y: R|@EnhancedNullability kotlin/CharSequence|): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
     public constructor(): R|A|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/typeQualifierDefault/ForceFlexibleOverOverrides.fir.txt

@@ -1,11 +1,11 @@
 @R|spr/NonNullApi|() public open class A : R|kotlin/Any|, R|B| {
-    @R|spr/ForceFlexibility|() public open fun foo(x: R|kotlin/String|): R|kotlin/Unit|
+    @R|spr/ForceFlexibility|() public open fun foo(x: R|@FlexibleNullability kotlin/String|): R|kotlin/Unit|
 
-    public open fun bar(@R|spr/ForceFlexibility|() x: R|kotlin/String|): R|kotlin/Unit|
+    public open fun bar(@R|spr/ForceFlexibility|() x: R|@FlexibleNullability kotlin/String|): R|kotlin/Unit|
 
-    public open fun baz(@R|spr/UnknownNullability|() x: R|kotlin/String|): R|kotlin/Unit|
+    public open fun baz(@R|spr/UnknownNullability|() x: R|@FlexibleNullability kotlin/String|): R|kotlin/Unit|
 
-    public open fun foobar(@R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.UNKNOWN|()) x: R|ft<kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
+    public open fun foobar(@R|javax/annotation/Nonnull|(R|javax/annotation/meta/When.UNKNOWN|()) x: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
 
     public constructor(): R|A|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/typeQualifierDefault/NullabilityFromOverridden.fir.txt

@@ -1,55 +1,55 @@
 @R|NonNullApi|() public open class A : R|kotlin/Any| {
-    public open fun foo1(x: R|kotlin/String|): R|kotlin/String|
+    public open fun foo1(x: R|@FlexibleNullability kotlin/String|): R|@FlexibleNullability kotlin/String|
 
-    public open fun foo2(x: R|kotlin/String|): R|kotlin/String|
+    public open fun foo2(x: R|@FlexibleNullability kotlin/String|): R|@FlexibleNullability kotlin/String|
 
-    public open fun foo3(x: R|kotlin/String|): R|kotlin/String|
+    public open fun foo3(x: R|@FlexibleNullability kotlin/String|): R|@FlexibleNullability kotlin/String|
 
-    @R|javax/annotation/Nullable|() public open fun bar1(@R|javax/annotation/Nullable|() x: R|kotlin/String?|): R|kotlin/String?|
+    @R|javax/annotation/Nullable|() public open fun bar1(@R|javax/annotation/Nullable|() x: R|@FlexibleNullability kotlin/String?|): R|@FlexibleNullability kotlin/String?|
 
-    @R|javax/annotation/Nullable|() public open fun bar2(@R|javax/annotation/Nullable|() x: R|kotlin/String?|): R|kotlin/String?|
+    @R|javax/annotation/Nullable|() public open fun bar2(@R|javax/annotation/Nullable|() x: R|@FlexibleNullability kotlin/String?|): R|@FlexibleNullability kotlin/String?|
 
-    public open fun baz(@R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|): R|kotlin/String|
+    public open fun baz(@R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|): R|@FlexibleNullability kotlin/String|
 
     public constructor(): R|A|
 
 }
 @R|NonNullApi|() public abstract interface AInt : R|kotlin/Any| {
-    public abstract fun foo1(x: R|kotlin/String|): R|kotlin/CharSequence|
+    public abstract fun foo1(x: R|@FlexibleNullability kotlin/String|): R|@FlexibleNullability kotlin/CharSequence|
 
-    public abstract fun foo2(x: R|kotlin/String|): R|kotlin/CharSequence|
+    public abstract fun foo2(x: R|@FlexibleNullability kotlin/String|): R|@FlexibleNullability kotlin/CharSequence|
 
-    public abstract fun foo3(x: R|kotlin/String|): R|kotlin/CharSequence|
+    public abstract fun foo3(x: R|@FlexibleNullability kotlin/String|): R|@FlexibleNullability kotlin/CharSequence|
 
-    @R|javax/annotation/Nullable|() public abstract fun bar1(@R|javax/annotation/Nullable|() x: R|kotlin/String?|): R|kotlin/CharSequence?|
+    @R|javax/annotation/Nullable|() public abstract fun bar1(@R|javax/annotation/Nullable|() x: R|@FlexibleNullability kotlin/String?|): R|@FlexibleNullability kotlin/CharSequence?|
 
-    @R|javax/annotation/Nullable|() public abstract fun bar2(@R|javax/annotation/Nullable|() x: R|kotlin/String?|): R|kotlin/CharSequence?|
+    @R|javax/annotation/Nullable|() public abstract fun bar2(@R|javax/annotation/Nullable|() x: R|@FlexibleNullability kotlin/String?|): R|@FlexibleNullability kotlin/CharSequence?|
 
-    public abstract fun baz(@R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|): R|kotlin/CharSequence|
+    public abstract fun baz(@R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|): R|@FlexibleNullability kotlin/CharSequence|
 
 }
 @R|NullableApi|() public open class B : R|A|, R|AInt| {
-    public open fun foo1(x: R|kotlin/String|): R|kotlin/String|
+    public open fun foo1(x: R|@FlexibleNullability kotlin/String|): R|@FlexibleNullability kotlin/String|
 
     @R|javax/annotation/Nonnull|() public open fun foo2(@R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|): R|@EnhancedNullability kotlin/String|
 
-    public open fun bar1(x: R|kotlin/String?|): R|kotlin/String?|
+    public open fun bar1(x: R|@FlexibleNullability kotlin/String?|): R|@FlexibleNullability kotlin/String?|
 
-    public open fun baz(x: R|kotlin/String|): R|kotlin/String|
+    public open fun baz(x: R|@FlexibleNullability kotlin/String|): R|@FlexibleNullability kotlin/String|
 
     public constructor(): R|B|
 
 }
 @R|NonNullApi|() public open class C : R|A|, R|AInt| {
-    public open fun foo1(x: R|kotlin/String|): R|kotlin/String|
+    public open fun foo1(x: R|@FlexibleNullability kotlin/String|): R|@FlexibleNullability kotlin/String|
 
-    public open fun foo2(@R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|): R|kotlin/String|
+    public open fun foo2(@R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|): R|@FlexibleNullability kotlin/String|
 
-    public open fun bar1(x: R|kotlin/String?|): R|kotlin/String?|
+    public open fun bar1(x: R|@FlexibleNullability kotlin/String?|): R|@FlexibleNullability kotlin/String?|
 
-    @R|javax/annotation/Nullable|() public open fun bar2(@R|javax/annotation/Nullable|() x: R|kotlin/String?|): R|kotlin/String?|
+    @R|javax/annotation/Nullable|() public open fun bar2(@R|javax/annotation/Nullable|() x: R|@FlexibleNullability kotlin/String?|): R|@FlexibleNullability kotlin/String?|
 
-    public open fun baz(x: R|kotlin/String|): R|kotlin/String|
+    public open fun baz(x: R|@FlexibleNullability kotlin/String|): R|@FlexibleNullability kotlin/String|
 
     public constructor(): R|C|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/typeQualifierDefault/OverridingDefaultQualifier.fir.txt

@@ -1,13 +1,13 @@
 @R|NonNullApi|() public open class A : R|kotlin/Any| {
-    public open field field: R|kotlin/String|
+    public open field field: R|@FlexibleNullability kotlin/String|
 
-    public open fun foo(x: R|kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|kotlin/CharSequence?|): R|kotlin/String|
+    public open fun foo(x: R|@FlexibleNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|@FlexibleNullability kotlin/CharSequence?|): R|@FlexibleNullability kotlin/String|
 
-    @R|NullableApi|() public open fun foobar(x: R|kotlin/String?|, @R|NonNullApi|() y: R|kotlin/CharSequence|): R|kotlin/String?|
+    @R|NullableApi|() public open fun foobar(x: R|@FlexibleNullability kotlin/String?|, @R|NonNullApi|() y: R|@FlexibleNullability kotlin/CharSequence|): R|@FlexibleNullability kotlin/String?|
 
-    public open fun bar(): R|kotlin/String|
+    public open fun bar(): R|@FlexibleNullability kotlin/String|
 
-    @R|javax/annotation/Nullable|() public open fun baz(): R|ft<kotlin/collections/MutableList<ft<kotlin/String, kotlin/String?>!>?, kotlin/collections/List<ft<kotlin/String, kotlin/String?>!>?>?|
+    @R|javax/annotation/Nullable|() public open fun baz(): R|ft<@FlexibleNullability kotlin/collections/MutableList<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?, kotlin/collections/List<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?>?|
 
     public constructor(): R|A|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/typeQualifierDefault/ParametersAreNonnullByDefault.fir.txt

@@ -1,7 +1,7 @@
 @R|javax/annotation/ParametersAreNonnullByDefault|() public open class A : R|kotlin/Any| {
-    @R|javax/annotation/Nullable|() public open field field: R|kotlin/String?|
+    @R|javax/annotation/Nullable|() public open field field: R|@FlexibleNullability kotlin/String?|
 
-    public open fun foo(q: R|kotlin/String|, @R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|kotlin/CharSequence?|): R|ft<kotlin/String, kotlin/String?>!|
+    public open fun foo(q: R|@FlexibleNullability kotlin/String|, @R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|@FlexibleNullability kotlin/CharSequence?|): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
     @R|javax/annotation/Nonnull|() public open fun bar(): R|@EnhancedNullability kotlin/String|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/typeQualifierDefault/ParametersAreNonnullByDefaultPackage.fir.txt

@@ -1,7 +1,7 @@
 public open class A : R|kotlin/Any| {
-    @R|javax/annotation/Nullable|() public open field field: R|kotlin/String?|
+    @R|javax/annotation/Nullable|() public open field field: R|@FlexibleNullability kotlin/String?|
 
-    public open fun foo(q: R|ft<kotlin/String, kotlin/String?>!|, @R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|kotlin/CharSequence?|): R|ft<kotlin/String, kotlin/String?>!|
+    public open fun foo(q: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, @R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|@FlexibleNullability kotlin/CharSequence?|): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
     @R|javax/annotation/Nonnull|() public open fun bar(): R|@EnhancedNullability kotlin/String|
 
@@ -9,9 +9,9 @@ public open class A : R|kotlin/Any| {
 
 }
 public open class A2 : R|kotlin/Any| {
-    @R|javax/annotation/Nullable|() public open field field: R|kotlin/String?|
+    @R|javax/annotation/Nullable|() public open field field: R|@FlexibleNullability kotlin/String?|
 
-    public open fun foo(q: R|ft<kotlin/String, kotlin/String?>!|, @R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|kotlin/CharSequence?|): R|ft<kotlin/String, kotlin/String?>!|
+    public open fun foo(q: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, @R|javax/annotation/Nonnull|() x: R|@EnhancedNullability kotlin/String|, @R|javax/annotation/CheckForNull|() y: R|@FlexibleNullability kotlin/CharSequence?|): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
     @R|javax/annotation/Nonnull|() public open fun bar(): R|@EnhancedNullability kotlin/String|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/typeQualifierDefault/SpringNullable.fir.txt

@@ -1,11 +1,11 @@
 @R|spr/NonNullApi|() public open class A : R|kotlin/Any| {
-    public open field field: R|ft<kotlin/String, kotlin/String?>!|
+    public open field field: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
-    public open fun foo(x: R|kotlin/String|, @R|spr/Nullable|() y: R|kotlin/CharSequence?|): R|kotlin/String|
+    public open fun foo(x: R|@FlexibleNullability kotlin/String|, @R|spr/Nullable|() y: R|@FlexibleNullability kotlin/CharSequence?|): R|@FlexibleNullability kotlin/String|
 
-    public open fun bar(): R|kotlin/String|
+    public open fun bar(): R|@FlexibleNullability kotlin/String|
 
-    @R|spr/Nullable|() public open fun baz(): R|ft<kotlin/collections/MutableList<ft<kotlin/String, kotlin/String?>!>?, kotlin/collections/List<ft<kotlin/String, kotlin/String?>!>?>?|
+    @R|spr/Nullable|() public open fun baz(): R|ft<@FlexibleNullability kotlin/collections/MutableList<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?, kotlin/collections/List<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?>?|
 
     public constructor(): R|A|
 

compiler/fir/analysis-tests/testData/enhancement/jsr305/typeQualifierDefault/SpringNullablePackage.fir.txt

@@ -1,11 +1,11 @@
 public open class A : R|kotlin/Any| {
-    public open field field: R|ft<kotlin/String, kotlin/String?>!|
+    public open field field: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
-    public open fun foo(x: R|ft<kotlin/String, kotlin/String?>!|, @R|spr/Nullable|() y: R|kotlin/CharSequence?|): R|ft<kotlin/String, kotlin/String?>!|
+    public open fun foo(x: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, @R|spr/Nullable|() y: R|@FlexibleNullability kotlin/CharSequence?|): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
-    public open fun bar(): R|ft<kotlin/String, kotlin/String?>!|
+    public open fun bar(): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
-    @R|spr/Nullable|() public open fun baz(): R|ft<kotlin/collections/MutableList<ft<kotlin/String, kotlin/String?>!>?, kotlin/collections/List<ft<kotlin/String, kotlin/String?>!>?>?|
+    @R|spr/Nullable|() public open fun baz(): R|ft<@FlexibleNullability kotlin/collections/MutableList<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?, kotlin/collections/List<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?>?|
 
     public constructor(): R|test/A|
 

compiler/fir/analysis-tests/testData/enhancement/mapping/AbstractMap.fir.txt

@@ -1,4 +1,4 @@
-public abstract class AbstractMap : R|kotlin/Any|, R|kotlin/collections/MutableMap<ft<kotlin/String, kotlin/String?>!, ft<kotlin/String, kotlin/String?>!>| {
+public abstract class AbstractMap : R|kotlin/Any|, R|kotlin/collections/MutableMap<ft<@FlexibleNullability kotlin/String, kotlin/String?>!, ft<@FlexibleNullability kotlin/String, kotlin/String?>!>| {
     public constructor(): R|AbstractMap|
 
 }

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/DefaultEnum.fir.txt

@@ -1,17 +1,17 @@
 public/*package*/ open class A : R|kotlin/Any| {
-    public open fun a(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(HELLO)) arg: R|ft<Signs, Signs?>!| = R|/Signs.HELLO|): R|ft<Signs, Signs?>!|
+    public open fun a(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(HELLO)) arg: R|ft<@FlexibleNullability Signs, Signs?>!| = R|/Signs.HELLO|): R|ft<@FlexibleNullability Signs, Signs?>!|
 
-    public open fun bar(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(X)) arg: R|ft<Signs, Signs?>!| = R|/Signs.X|): R|ft<Signs, Signs?>!|
+    public open fun bar(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(X)) arg: R|ft<@FlexibleNullability Signs, Signs?>!| = R|/Signs.X|): R|ft<@FlexibleNullability Signs, Signs?>!|
 
-    public open fun baz(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(NOT_ENTRY_EITHER)) arg: R|ft<Signs, Signs?>!|): R|ft<Signs, Signs?>!|
+    public open fun baz(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(NOT_ENTRY_EITHER)) arg: R|ft<@FlexibleNullability Signs, Signs?>!|): R|ft<@FlexibleNullability Signs, Signs?>!|
 
-    public open fun bam(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(NOT_ENTRY_EITHER)) arg: R|ft<Mixed, Mixed?>!| = R|/Mixed.NOT_ENTRY_EITHER|): R|ft<Mixed, Mixed?>!|
+    public open fun bam(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(NOT_ENTRY_EITHER)) arg: R|ft<@FlexibleNullability Mixed, Mixed?>!| = R|/Mixed.NOT_ENTRY_EITHER|): R|ft<@FlexibleNullability Mixed, Mixed?>!|
 
     public/*package*/ constructor(): R|A|
 
 }
-public final enum class Mixed : R|kotlin/Enum<ft<Mixed, Mixed?>!>| {
+public final enum class Mixed : R|kotlin/Enum<ft<@FlexibleNullability Mixed, Mixed?>!>| {
-    public final static enum entry NOT_ENTRY_EITHER: R|Mixed|
+    public final static enum entry NOT_ENTRY_EITHER: R|@FlexibleNullability Mixed|
     public final static fun values(): R|kotlin/Array<Mixed>| {
     }
 
@@ -19,10 +19,10 @@ public final enum class Mixed : R|kotlin/Enum<ft<Mixed, Mixed?>!>| {
     }
 
 }
-public final enum class Signs : R|kotlin/Enum<ft<Signs, Signs?>!>| {
+public final enum class Signs : R|kotlin/Enum<ft<@FlexibleNullability Signs, Signs?>!>| {
-    public final static enum entry HELLO: R|Signs|
+    public final static enum entry HELLO: R|@FlexibleNullability Signs|
-    public final static enum entry WORLD: R|Signs|
+    public final static enum entry WORLD: R|@FlexibleNullability Signs|
-    public final static field X: R|ft<Signs, Signs?>!|
+    public final static field X: R|ft<@FlexibleNullability Signs, Signs?>!|
 
     public final static fun values(): R|kotlin/Array<Signs>| {
     }

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/DefaultLongLiteral.fir.txt

@@ -1,23 +1,23 @@
 public open class A : R|kotlin/Any| {
-    public open fun first(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0x1F)) value: R|ft<kotlin/Long, kotlin/Long?>!| = Long(31)): R|kotlin/Unit|
+    public open fun first(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0x1F)) value: R|ft<@FlexibleNullability kotlin/Long, kotlin/Long?>!| = Long(31)): R|kotlin/Unit|
 
-    public open fun second(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0X1F)) value: R|ft<kotlin/Long, kotlin/Long?>!| = Long(31)): R|kotlin/Unit|
+    public open fun second(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0X1F)) value: R|ft<@FlexibleNullability kotlin/Long, kotlin/Long?>!| = Long(31)): R|kotlin/Unit|
 
-    public open fun third(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0b1010)) value: R|ft<kotlin/Long, kotlin/Long?>!| = Long(10)): R|kotlin/Unit|
+    public open fun third(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0b1010)) value: R|ft<@FlexibleNullability kotlin/Long, kotlin/Long?>!| = Long(10)): R|kotlin/Unit|
 
-    public open fun fourth(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0B1010)) value: R|ft<kotlin/Long, kotlin/Long?>!| = Long(10)): R|kotlin/Unit|
+    public open fun fourth(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0B1010)) value: R|ft<@FlexibleNullability kotlin/Long, kotlin/Long?>!| = Long(10)): R|kotlin/Unit|
 
     public constructor(): R|A|
 
 }
 public open class B : R|kotlin/Any| {
-    public open fun first(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0x)) value: R|ft<kotlin/Long, kotlin/Long?>!|): R|kotlin/Unit|
+    public open fun first(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0x)) value: R|ft<@FlexibleNullability kotlin/Long, kotlin/Long?>!|): R|kotlin/Unit|
 
-    public open fun second(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0xZZ)) value: R|ft<kotlin/Long, kotlin/Long?>!|): R|kotlin/Unit|
+    public open fun second(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0xZZ)) value: R|ft<@FlexibleNullability kotlin/Long, kotlin/Long?>!|): R|kotlin/Unit|
 
-    public open fun third(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0b)) value: R|ft<kotlin/Long, kotlin/Long?>!|): R|kotlin/Unit|
+    public open fun third(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0b)) value: R|ft<@FlexibleNullability kotlin/Long, kotlin/Long?>!|): R|kotlin/Unit|
 
-    public open fun fourth(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0B1234)) value: R|ft<kotlin/Long, kotlin/Long?>!|): R|kotlin/Unit|
+    public open fun fourth(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(0B1234)) value: R|ft<@FlexibleNullability kotlin/Long, kotlin/Long?>!|): R|kotlin/Unit|
 
     public constructor(): R|B|
 

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/DefaultNull.fir.txt

@@ -1,5 +1,5 @@
 public open class A : R|kotlin/Any| {
-    public open fun foo(@R|kotlin/annotations/jvm/internal/DefaultNull|() x: R|ft<kotlin/Int, kotlin/Int?>!| = Null(null)): R|kotlin/Unit|
+    public open fun foo(@R|kotlin/annotations/jvm/internal/DefaultNull|() x: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| = Null(null)): R|kotlin/Unit|
 
     public open fun bar(@R|kotlin/annotations/jvm/internal/DefaultNull|() x: R|kotlin/Int| = Null(null)): R|kotlin/Unit|
 
@@ -7,7 +7,7 @@ public open class A : R|kotlin/Any| {
 
 }
 public open class B<T : R|ft<kotlin/Any, kotlin/Any?>!|> : R|kotlin/Any| {
-    public open fun foo(@R|kotlin/annotations/jvm/internal/DefaultNull|() t: R|ft<T, T?>!| = Null(null)): R|kotlin/Unit|
+    public open fun foo(@R|kotlin/annotations/jvm/internal/DefaultNull|() t: R|ft<@FlexibleNullability T, T?>!| = Null(null)): R|kotlin/Unit|
 
     public constructor<T : R|ft<kotlin/Any, kotlin/Any?>!|>(): R|B<T>|
 

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/DefaultNullAndParameter.fir.txt

@@ -1,27 +1,27 @@
 public open class A : R|kotlin/Any| {
-    public open fun foo(@R|kotlin/annotations/jvm/internal/DefaultNull|() i: R|ft<kotlin/Int, kotlin/Int?>!| = Null(null)): R|kotlin/Unit|
+    public open fun foo(@R|kotlin/annotations/jvm/internal/DefaultNull|() i: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| = Null(null)): R|kotlin/Unit|
 
-    public open fun bar(@R|kotlin/annotations/jvm/internal/DefaultNull|() a: R|ft<kotlin/Int, kotlin/Int?>!| = Null(null)): R|kotlin/Unit|
+    public open fun bar(@R|kotlin/annotations/jvm/internal/DefaultNull|() a: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| = Null(null)): R|kotlin/Unit|
 
-    public open fun bam(@R|kotlin/annotations/jvm/internal/DefaultNull|() a: R|ft<kotlin/Int, kotlin/Int?>!| = Null(null)): R|kotlin/Unit|
+    public open fun bam(@R|kotlin/annotations/jvm/internal/DefaultNull|() a: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| = Null(null)): R|kotlin/Unit|
 
-    public open fun baz(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(42)) a: R|ft<kotlin/Int, kotlin/Int?>!| = Int(42)): R|kotlin/Unit|
+    public open fun baz(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(42)) a: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| = Int(42)): R|kotlin/Unit|
 
     public constructor(): R|A|
 
 }
 public abstract interface AInt : R|kotlin/Any| {
-    public abstract fun foo(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(42)) i: R|ft<kotlin/Int, kotlin/Int?>!| = Int(42)): R|kotlin/Unit|
+    public abstract fun foo(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(42)) i: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| = Int(42)): R|kotlin/Unit|
 
-    public abstract fun bar(@R|kotlin/annotations/jvm/internal/DefaultNull|() a: R|ft<kotlin/Int, kotlin/Int?>!| = Null(null)): R|kotlin/Unit|
+    public abstract fun bar(@R|kotlin/annotations/jvm/internal/DefaultNull|() a: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| = Null(null)): R|kotlin/Unit|
 
 }
 public open class B : R|A| {
-    public open fun foo(i: R|ft<kotlin/Int, kotlin/Int?>!|): R|kotlin/Unit|
+    public open fun foo(i: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!|): R|kotlin/Unit|
 
-    public open fun bar(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(42)) a: R|ft<kotlin/Int, kotlin/Int?>!| = Int(42)): R|kotlin/Unit|
+    public open fun bar(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(42)) a: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| = Int(42)): R|kotlin/Unit|
 
-    public open fun bam(@R|kotlin/annotations/jvm/internal/DefaultNull|() @R|kotlin/annotations/jvm/internal/DefaultValue|(String(42)) a: R|ft<kotlin/Int, kotlin/Int?>!| = Int(42)): R|kotlin/Unit|
+    public open fun bam(@R|kotlin/annotations/jvm/internal/DefaultNull|() @R|kotlin/annotations/jvm/internal/DefaultValue|(String(42)) a: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| = Int(42)): R|kotlin/Unit|
 
     public constructor(): R|B|
 

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/DefaultParameter.fir.txt

@@ -1,13 +1,13 @@
 public/*package*/ open class A : R|kotlin/Any| {
-    public open fun first(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(hello)) value: R|ft<kotlin/String, kotlin/String?>!| = String(hello)): R|kotlin/Unit|
+    public open fun first(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(hello)) value: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = String(hello)): R|kotlin/Unit|
 
-    public open fun second(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(first)) a: R|ft<kotlin/String, kotlin/String?>!| = String(first), @R|kotlin/annotations/jvm/internal/DefaultValue|(String(second)) b: R|ft<kotlin/String, kotlin/String?>!| = String(second)): R|kotlin/Unit|
+    public open fun second(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(first)) a: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = String(first), @R|kotlin/annotations/jvm/internal/DefaultValue|(String(second)) b: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = String(second)): R|kotlin/Unit|
 
-    public open fun third(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(first)) a: R|ft<kotlin/String, kotlin/String?>!| = String(first), b: R|ft<kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
+    public open fun third(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(first)) a: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = String(first), b: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
 
-    public open fun fourth(first: R|ft<kotlin/String, kotlin/String?>!|, @R|kotlin/annotations/jvm/internal/DefaultValue|(String(second)) second: R|ft<kotlin/String, kotlin/String?>!| = String(second)): R|kotlin/Unit|
+    public open fun fourth(first: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, @R|kotlin/annotations/jvm/internal/DefaultValue|(String(second)) second: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = String(second)): R|kotlin/Unit|
 
-    public open fun wrong(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(hello)) i: R|ft<kotlin/Int, kotlin/Int?>!|): R|kotlin/Unit|
+    public open fun wrong(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(hello)) i: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!|): R|kotlin/Unit|
 
     public/*package*/ constructor(): R|A|
 

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/EmptyParameterName.fir.txt

@@ -1,9 +1,9 @@
 public/*package*/ open class A : R|kotlin/Any| {
-    public open fun emptyName(@R|kotlin/annotations/jvm/internal/ParameterName|(String()) first: R|ft<kotlin/String, kotlin/String?>!|, @R|kotlin/annotations/jvm/internal/ParameterName|(String(ok)) second: R|kotlin/Int|): R|kotlin/Unit|
+    public open fun emptyName(@R|kotlin/annotations/jvm/internal/ParameterName|(String()) first: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, @R|kotlin/annotations/jvm/internal/ParameterName|(String(ok)) second: R|kotlin/Int|): R|kotlin/Unit|
 
-    public open fun missingName(@R|kotlin/annotations/jvm/internal/ParameterName|() first: R|ft<kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
+    public open fun missingName(@R|kotlin/annotations/jvm/internal/ParameterName|() first: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
 
-    public open fun numberName(@R|kotlin/annotations/jvm/internal/ParameterName|(Int(42)) first: R|ft<kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
+    public open fun numberName(@R|kotlin/annotations/jvm/internal/ParameterName|(Int(42)) first: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
 
     public/*package*/ constructor(): R|A|
 

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/ReorderedParameterNames.fir.txt

@@ -1,5 +1,5 @@
 public open class A : R|kotlin/Any| {
-    public open fun connect(@R|kotlin/annotations/jvm/internal/ParameterName|(String(host)) host: R|ft<kotlin/String, kotlin/String?>!|, @R|kotlin/annotations/jvm/internal/ParameterName|(String(port)) port: R|kotlin/Int|): R|kotlin/Unit|
+    public open fun connect(@R|kotlin/annotations/jvm/internal/ParameterName|(String(host)) host: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, @R|kotlin/annotations/jvm/internal/ParameterName|(String(port)) port: R|kotlin/Int|): R|kotlin/Unit|
 
     public constructor(): R|A|
 

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/SameParameterName.fir.txt

@@ -1,5 +1,5 @@
 public open class A : R|kotlin/Any| {
-    public open fun same(@R|kotlin/annotations/jvm/internal/ParameterName|(String(ok)) first: R|ft<kotlin/String, kotlin/String?>!|, @R|kotlin/annotations/jvm/internal/ParameterName|(String(ok)) second: R|ft<kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
+    public open fun same(@R|kotlin/annotations/jvm/internal/ParameterName|(String(ok)) first: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, @R|kotlin/annotations/jvm/internal/ParameterName|(String(ok)) second: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
 
     public constructor(): R|A|
 

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/SpecialCharsParameterName.fir.txt

@@ -1,7 +1,7 @@
 public open class A : R|kotlin/Any| {
-    public open fun dollarName(@R|kotlin/annotations/jvm/internal/ParameterName|(String($)) host: R|ft<kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
+    public open fun dollarName(@R|kotlin/annotations/jvm/internal/ParameterName|(String($)) host: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
 
-    public open fun numberName(@R|kotlin/annotations/jvm/internal/ParameterName|(String(42)) field: R|ft<kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
+    public open fun numberName(@R|kotlin/annotations/jvm/internal/ParameterName|(String(42)) field: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|): R|kotlin/Unit|
 
     public constructor(): R|A|
 

compiler/fir/analysis-tests/testData/enhancement/signatureAnnotations/StaticMethodWithDefaultValue.fir.txt

@@ -1,5 +1,5 @@
 public/*package*/ open class A : R|kotlin/Any| {
-    public open static fun withDefault(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(OK)) arg: R|ft<kotlin/String, kotlin/String?>!| = String(OK)): R|ft<kotlin/String, kotlin/String?>!|
+    public open static fun withDefault(@R|kotlin/annotations/jvm/internal/DefaultValue|(String(OK)) arg: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = String(OK)): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
     public/*package*/ constructor(): R|A|
 

compiler/fir/analysis-tests/testData/extendedCheckers/canBeReplacedWithOperatorAssignment/flexibleTypeBug.txt

@@ -1,6 +1,6 @@
 FILE: flexibleTypeBug.kt
     public final fun foo(): R|kotlin/Unit| {
-        lvar list1: R|ft<kotlin/collections/MutableList<ft<kotlin/String, kotlin/String?>!>, kotlin/collections/List<ft<kotlin/String, kotlin/String?>!>?>!| = Q|java/util/Collections|.R|java/util/Collections.emptyList|<R|ft<kotlin/String, kotlin/String?>!|>()
+        lvar list1: R|ft<@FlexibleNullability kotlin/collections/MutableList<ft<kotlin/String, kotlin/String?>!>, kotlin/collections/List<ft<kotlin/String, kotlin/String?>!>?>!| = Q|java/util/Collections|.R|java/util/Collections.emptyList|<R|ft<kotlin/String, kotlin/String?>!|>()
         lval list2: R|kotlin/collections/List<kotlin/String>| = R|kotlin/collections/listOf|<R|kotlin/String|>(String(b))
         R|<local>/list1| = R|<local>/list1|.R|kotlin/collections/plus|<R|ft<kotlin/String, kotlin/String?>!|>(R|<local>/list2|)
     }

compiler/fir/analysis-tests/testData/resolve/exhaustiveWhenAndFlexibleType.txt

@@ -15,7 +15,7 @@ FILE: main.kt
 
     }
     public final fun test_1(): R|kotlin/Unit| {
-        lval e: R|ft<E, E?>!| = Q|Utils|.R|/Utils.getEnum|()
+        lval e: R|ft<@FlexibleNullability E, E?>!| = Q|Utils|.R|/Utils.getEnum|()
         lval s: R|kotlin/String| = when (R|<local>/e|) {
             ==($subj$, Null(null)) ->  {
                 ^test_1 Unit
@@ -34,7 +34,7 @@ FILE: main.kt
         R|<local>/s|.R|kotlin/String.length|
     }
     public final fun test_2(): R|kotlin/Unit| {
-        lval e: R|ft<E, E?>!| = Q|Utils|.R|/Utils.getEnum|()
+        lval e: R|ft<@FlexibleNullability E, E?>!| = Q|Utils|.R|/Utils.getEnum|()
         lval s: R|kotlin/String| = when (R|<local>/e|) {
             ==($subj$, Q|E|.R|/E.A|) ->  {
                 String()

compiler/fir/analysis-tests/testData/resolve/expresssions/genericDiagnostic.txt

@@ -16,7 +16,7 @@ FILE: test.kt
     private final val DERIVED_FACTORY: R|DiagnosticFactory0<ft<DerivedElement, DerivedElement?>!>| = R|/DiagnosticFactory0.DiagnosticFactory0|<R|ft<DerivedElement, DerivedElement?>!|>()
         private get(): R|DiagnosticFactory0<ft<DerivedElement, DerivedElement?>!>|
     public final fun createViaFactory(d: R|EmptyDiagnostic|): R|kotlin/Unit| {
-        lval casted: R|Diagnostic<ft<DerivedElement, DerivedElement?>!>| = R|/DERIVED_FACTORY|.R|SubstitutionOverride</DiagnosticFactory0.cast: R|Diagnostic<ft<DerivedElement, DerivedElement?>!>|>|(R|<local>/d|)
+        lval casted: R|@FlexibleNullability Diagnostic<ft<DerivedElement, DerivedElement?>!>| = R|/DERIVED_FACTORY|.R|SubstitutionOverride</DiagnosticFactory0.cast: R|@FlexibleNullability Diagnostic<ft<DerivedElement, DerivedElement?>!>|>|(R|<local>/d|)
         lval element: R|DerivedElement| = R|<local>/casted|.R|/Diagnostic.element|
         R|/Fix.Fix|(R|<local>/element|)
     }

compiler/fir/analysis-tests/testData/resolve/expresssions/javaFieldCallable.txt

@@ -1,5 +1,5 @@
 FILE: test.kt
     public final fun test(): R|kotlin/Unit| {
-        lval staticReference: R|kotlin/reflect/KMutableProperty0<ft<kotlin/String, kotlin/String?>!>| = Q|JavaClass|::R|/JavaClass.staticField|
+        lval staticReference: R|kotlin/reflect/KMutableProperty0<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>| = Q|JavaClass|::R|/JavaClass.staticField|
-        lval nonStaticReference: R|kotlin/reflect/KMutableProperty1<JavaClass, ft<kotlin/String, kotlin/String?>!>| = Q|JavaClass|::R|/JavaClass.nonStaticField|
+        lval nonStaticReference: R|kotlin/reflect/KMutableProperty1<JavaClass, ft<@FlexibleNullability kotlin/String, kotlin/String?>!>| = Q|JavaClass|::R|/JavaClass.nonStaticField|
     }

compiler/fir/analysis-tests/testData/resolve/expresssions/outerMemberAccesses.txt

@@ -37,7 +37,7 @@ FILE: O.kt
                         }
 
                         public final fun local(): R|kotlin/Unit| {
-                            lval y: R|ft<kotlin/String, kotlin/String?>!| = this@R|/O.Derived|.R|/Base.foo|()
+                            lval y: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = this@R|/O.Derived|.R|/Base.foo|()
                         }
 
                         public final val oo: R|<anonymous>| = object : R|kotlin/Any| {
@@ -66,7 +66,7 @@ FILE: O.kt
                     }
 
                     public final fun local(): R|kotlin/Unit| {
-                        lval y: R|ft<kotlin/String, kotlin/String?>!| = this@R|/O.Derived|.R|/Base.foo|()
+                        lval y: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = this@R|/O.Derived|.R|/Base.foo|()
                     }
 
                 }

compiler/fir/analysis-tests/testData/resolve/expresssions/syntheticSmartCast.txt

@@ -20,7 +20,7 @@ FILE: test.kt
         R|<local>/x|.R|/AnotherClass.bar|
     }
     public final fun test2(x: R|SomeClass?|): R|kotlin/Unit| {
-        lval bar: R|kotlin/CharSequence| = R|<local>/x|?.{ $subj$.R|/SomeClass.bar| } ?: ^test2 Unit
+        lval bar: R|@FlexibleNullability kotlin/CharSequence| = R|<local>/x|?.{ $subj$.R|/SomeClass.bar| } ?: ^test2 Unit
         R|<local>/x|.R|/SomeClass.bar|
     }
     public final fun test3(x: R|AnotherClass?|): R|kotlin/Unit| {
@@ -33,7 +33,7 @@ FILE: test.kt
 
     }
     public final fun test4(x: R|SomeClass?|): R|kotlin/Unit| {
-        lval bar: R|kotlin/CharSequence?| = R|<local>/x|?.{ $subj$.R|/SomeClass.bar| }
+        lval bar: R|@FlexibleNullability kotlin/CharSequence?| = R|<local>/x|?.{ $subj$.R|/SomeClass.bar| }
         when () {
             !=(R|<local>/bar|, Null(null)) ->  {
                 R|<local>/x|.R|/SomeClass.bar|.<Inapplicable(INAPPLICABLE_WRONG_RECEIVER): kotlin/CharSequence.length>#

compiler/fir/analysis-tests/testData/resolve/inference/capturedTypeForJavaTypeParameter.txt

@@ -4,5 +4,5 @@ FILE: main.kt
     public final fun <D : R|A|> foo(b: R|B<D>|): R|kotlin/Unit| {
     }
     public final fun main(b: R|B<*>|): R|kotlin/Unit| {
-        R|/foo|<R|ft<A, A?>!|>(R|<local>/b|)
+        R|/foo|<R|ft<@FlexibleNullability A, A?>!|>(R|<local>/b|)
     }

compiler/fir/analysis-tests/testData/resolve/javaFieldVsAccessor.txt

@@ -1,5 +1,5 @@
 FILE: main.kt
     public final fun test(a: R|A|): R|kotlin/Unit| {
         lval int: R|kotlin/Int| = R|<local>/a|.R|/A.x|
-        lval string: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/a|.R|/A.getX|()
+        lval string: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/a|.R|/A.getX|()
     }

compiler/fir/analysis-tests/testData/resolve/javaStaticScopeInheritance.txt

@@ -1,4 +1,4 @@
 FILE: main.kt
     public final fun main(): R|kotlin/Unit| {
-        lval b: R|ft<B, B?>!| = Q|B|.R|/B.VALUE|
+        lval b: R|ft<@FlexibleNullability B, B?>!| = Q|B|.R|/B.VALUE|
     }

compiler/fir/analysis-tests/testData/resolve/properties/javaAccessorConversion.txt

@@ -1,10 +1,10 @@
 FILE: main.kt
     public final fun test_1(x: R|A|): R|kotlin/Unit| {
-        lval str1: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/x|.R|/A.vmParameters|
+        lval str1: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/x|.R|/A.vmParameters|
         lval str2: R|ERROR CLASS: Unresolved name: vMParameters| = R|<local>/x|.<Unresolved name: vMParameters>#
     }
     public final fun test_2(x: R|B|): R|kotlin/Unit| {
-        lval int: R|ft<kotlin/Int, kotlin/Int?>!| = R|<local>/x|.R|/B.vmParameters|
+        lval int: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| = R|<local>/x|.R|/B.vmParameters|
         lval error: R|ERROR CLASS: Unresolved name: vMParameters| = R|<local>/x|.<Unresolved name: vMParameters>#
     }
     public final fun test_3(x: R|C|): R|kotlin/Unit| {

compiler/fir/analysis-tests/testData/resolve/rawTypeSam.txt

@@ -1,6 +1,6 @@
 FILE: main.kt
     public final fun foo(): R|kotlin/Unit| {
-        Q|RawType|.R|/RawType.bar|(<L> = bar@fun <anonymous>(it: R|ft<kotlin/CharSequence, kotlin/CharSequence?>!|): R|kotlin/Boolean| {
+        Q|RawType|.R|/RawType.bar|(<L> = bar@fun <anonymous>(it: R|ft<@FlexibleNullability kotlin/CharSequence, @FlexibleNullability kotlin/CharSequence?>!|): R|kotlin/Boolean| {
             ^ CMP(>, R|<local>/it|.R|kotlin/CharSequence.length|.R|kotlin/Int.compareTo|(Int(0)))
         }
         )

compiler/fir/analysis-tests/testData/resolve/samConversions/genericSam.txt

@@ -1,14 +1,14 @@
 FILE: main.kt
     public final fun main(): R|kotlin/Unit| {
-        Q|JavaUsage|.R|/JavaUsage.foo1|(<L> = foo1@fun <anonymous>(x: R|ft<kotlin/Int, kotlin/Int?>!|): R|ft<kotlin/String, kotlin/String?>!| {
+        Q|JavaUsage|.R|/JavaUsage.foo1|(<L> = foo1@fun <anonymous>(x: R|ft<@FlexibleNullability kotlin/Int, @FlexibleNullability kotlin/Int?>!|): R|ft<@FlexibleNullability kotlin/String, @FlexibleNullability kotlin/String?>!| {
             ^ R|<local>/x|.R|kotlin/Int.toInt|().R|kotlin/Any.toString|()
         }
         )
-        Q|JavaUsage|.R|/JavaUsage.foo2|(<L> = foo2@fun <anonymous>(x: R|ft<kotlin/Number, kotlin/Number?>!|): R|ft<kotlin/CharSequence, kotlin/CharSequence?>!| {
+        Q|JavaUsage|.R|/JavaUsage.foo2|(<L> = foo2@fun <anonymous>(x: R|ft<@FlexibleNullability kotlin/Number, @FlexibleNullability kotlin/Number?>!|): R|ft<@FlexibleNullability kotlin/CharSequence, @FlexibleNullability kotlin/CharSequence?>!| {
             ^ R|<local>/x|.R|kotlin/Number.toInt|().R|kotlin/Any.toString|()
         }
         )
-        Q|JavaUsage|.<Inapplicable(INAPPLICABLE): /JavaUsage.foo2>#(<L> = foo2@fun <anonymous>(x: R|kotlin/Int|): R|ft<kotlin/CharSequence, kotlin/CharSequence?>!| {
+        Q|JavaUsage|.<Inapplicable(INAPPLICABLE): /JavaUsage.foo2>#(<L> = foo2@fun <anonymous>(x: R|kotlin/Int|): R|ft<@FlexibleNullability kotlin/CharSequence, @FlexibleNullability kotlin/CharSequence?>!| {
             ^ R|<local>/x|.R|kotlin/Any.toString|()
         }
         )

compiler/fir/analysis-tests/testData/resolve/samConversions/samSupertypeWithOverride.txt

@@ -2,11 +2,11 @@ FILE: main.kt
     public final fun foo(m: R|MyRunnable|): R|kotlin/Unit| {
     }
     public final fun main(): R|kotlin/Unit| {
-        Q|JavaUsage|.R|/JavaUsage.foo|(<L> = foo@fun <anonymous>(x: R|kotlin/Int|): R|ft<kotlin/Boolean, kotlin/Boolean?>!| {
+        Q|JavaUsage|.R|/JavaUsage.foo|(<L> = foo@fun <anonymous>(x: R|kotlin/Int|): R|ft<@FlexibleNullability kotlin/Boolean, kotlin/Boolean?>!| {
             ^ CMP(>, R|<local>/x|.R|kotlin/Int.compareTo|(Int(1)))
         }
         )
-        Q|JavaUsage|.R|/JavaUsage.foo|(foo@fun <anonymous>(it: R|kotlin/Int|): R|ft<kotlin/Boolean, kotlin/Boolean?>!| {
+        Q|JavaUsage|.R|/JavaUsage.foo|(foo@fun <anonymous>(it: R|kotlin/Int|): R|ft<@FlexibleNullability kotlin/Boolean, kotlin/Boolean?>!| {
             ^ CMP(>, R|<local>/it|.R|kotlin/Int.compareTo|(Int(1)))
         }
         )

compiler/fir/analysis-tests/testData/resolve/samConversions/samWithEquals.txt

@@ -5,7 +5,7 @@ FILE: main.kt
 
     }
     public final fun main(): R|kotlin/Unit| {
-        Q|OverridingUtil|.R|/OverridingUtil.createWithEqualityAxioms|(<L> = l1@fun <anonymous>(c1: R|ft<TypeConstructor, TypeConstructor?>!|, c2: R|ft<TypeConstructor, TypeConstructor?>!|): R|kotlin/Boolean| {
+        Q|OverridingUtil|.R|/OverridingUtil.createWithEqualityAxioms|(<L> = l1@fun <anonymous>(c1: R|ft<@FlexibleNullability TypeConstructor, TypeConstructor?>!|, c2: R|ft<@FlexibleNullability TypeConstructor, TypeConstructor?>!|): R|kotlin/Boolean| {
             when () {
                 ==(R|<local>/c1|.R|/TypeConstructor.x|, R|<local>/c2|.R|/TypeConstructor.x|) ->  {
                     ^@l1 Boolean(true)

compiler/fir/analysis-tests/testData/resolve/spreadOperator.txt

@@ -16,7 +16,7 @@ FILE: Main.kt
         R|/takeStrings|(R|<local>/list|)
     }
     public final fun testFromJava(): R|kotlin/Unit| {
-        lval values: R|ft<kotlin/Array<ft<kotlin/String, kotlin/String?>!>, kotlin/Array<out ft<kotlin/String, kotlin/String?>!>?>!| = Q|Utils|.R|/Utils.getStrings|()
+        lval values: R|ft<@FlexibleNullability kotlin/Array<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>, kotlin/Array<out ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?>!| = Q|Utils|.R|/Utils.getStrings|()
-        lval list: R|kotlin/collections/List<ft<kotlin/String, kotlin/String?>!>| = R|/myListOf|<R|ft<kotlin/String, kotlin/String?>!|>(vararg(*R|<local>/values|))
+        lval list: R|kotlin/collections/List<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>| = R|/myListOf|<R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>(vararg(*R|<local>/values|))
         R|/takeStrings|(R|<local>/list|)
     }

compiler/fir/analysis-tests/testData/resolve/stdlib/j+k/ArrayInGenericArguments.txt

@@ -1,5 +1,5 @@
 FILE: main.kt
     public final fun main(): R|kotlin/Unit| {
-        Q|Keys|.R|/Keys.getData|<R|ft<kotlin/Array<ft<kotlin/String, kotlin/String?>!>, kotlin/Array<out ft<kotlin/String, kotlin/String?>!>?>!|>(Q|Keys|.R|/Keys.X|).R|SubstitutionOverride<kotlin/Array.get: R|ft<kotlin/String, kotlin/String?>!|>|(Int(0)).R|kotlin/String.length|
+        Q|Keys|.R|/Keys.getData|<R|ft<@FlexibleNullability kotlin/Array<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>, kotlin/Array<out ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?>!|>(Q|Keys|.R|/Keys.X|).R|SubstitutionOverride<kotlin/Array.get: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>|(Int(0)).R|kotlin/String.length|
-        Q|Keys|.R|/Keys.getData|<R|ft<kotlin/String, kotlin/String?>!|>(Q|Keys|.R|/Keys.Y|).R|kotlin/String.length|
+        Q|Keys|.R|/Keys.getData|<R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>(Q|Keys|.R|/Keys.Y|).R|kotlin/String.length|
     }

compiler/fir/analysis-tests/testData/resolve/stdlib/j+k/flexibleWildcard.txt

@@ -1,5 +1,5 @@
 FILE: main.kt
     public final fun main(x: R|kotlin/collections/MutableCollection<kotlin/collections/Set<kotlin/String>>|): R|kotlin/Unit| {
-        lval y: R|ft<kotlin/collections/MutableList<ft<kotlin/String, kotlin/String?>!>, kotlin/collections/List<ft<kotlin/String, kotlin/String?>!>?>!| = Q|ContainerUtil|.R|/ContainerUtil.flatten|<R|ft<kotlin/String, kotlin/String?>!|>(R|<local>/x|)
+        lval y: R|ft<@FlexibleNullability kotlin/collections/MutableList<ft<kotlin/String, kotlin/String?>!>, kotlin/collections/List<ft<kotlin/String, kotlin/String?>!>?>!| = Q|ContainerUtil|.R|/ContainerUtil.flatten|<R|ft<kotlin/String, kotlin/String?>!|>(R|<local>/x|)
         R|<local>/y|.R|SubstitutionOverride<kotlin/collections/MutableList.get: R|ft<kotlin/String, kotlin/String?>!|>|(Int(0)).R|kotlin/String.length|
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/inference/flexibleTypeInSystem.txt

@@ -1,3 +1,3 @@
 FILE: main.kt
-    public final val enumMap: R|java/util/EnumMap<ft<JavaEnum, JavaEnum?>!, ft<kotlin/String, kotlin/String?>!>| = R|java/util/EnumMap.EnumMap|<R|ft<JavaEnum, JavaEnum?>!|, R|ft<kotlin/String, kotlin/String?>!|>(R|kotlin/collections/mapOf|<R|ft<JavaEnum, JavaEnum?>!|, R|kotlin/String|>(Q|JavaEnum|.R|/JavaEnum.A|.R|kotlin/to|<R|JavaEnum|, R|kotlin/String|>(String(A))))
+    public final val enumMap: R|java/util/EnumMap<ft<@FlexibleNullability JavaEnum, JavaEnum?>!, ft<kotlin/String, kotlin/String?>!>| = R|java/util/EnumMap.EnumMap|<R|ft<@FlexibleNullability JavaEnum, JavaEnum?>!|, R|ft<kotlin/String, kotlin/String?>!|>(R|kotlin/collections/mapOf|<R|ft<@FlexibleNullability JavaEnum, JavaEnum?>!|, R|kotlin/String|>(Q|JavaEnum|.R|/JavaEnum.A|.R|kotlin/to|<R|@FlexibleNullability JavaEnum|, R|kotlin/String|>(String(A))))
-        public get(): R|java/util/EnumMap<ft<JavaEnum, JavaEnum?>!, ft<kotlin/String, kotlin/String?>!>|
+        public get(): R|java/util/EnumMap<ft<@FlexibleNullability JavaEnum, JavaEnum?>!, ft<kotlin/String, kotlin/String?>!>|

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/BasicWithAnnotatedOverriddenJava.txt

@@ -5,8 +5,8 @@ FILE: jvm.kt
         }
 
         public final fun test(): R|kotlin/Unit| {
-            lval x: R|kotlin/String| = this@R|/User|.R|/AnnotatedDerived.foo|(String(123))
+            lval x: R|@FlexibleNullability kotlin/String| = this@R|/User|.R|/AnnotatedDerived.foo|(String(123))
-            lval y: R|kotlin/String| = this@R|/User|.R|/AnnotatedDerived.foo|(Null(null))
+            lval y: R|@FlexibleNullability kotlin/String| = this@R|/User|.R|/AnnotatedDerived.foo|(Null(null))
         }
 
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/BasicWithPrimitiveJava.txt

@@ -7,7 +7,7 @@ FILE: jvm.kt
         public final fun test(): R|kotlin/Unit| {
             lval res1: R|kotlin/Boolean| = this@R|/A|.R|/Some.foo|(Int(1))
             lval res2: R|kotlin/Boolean| = this@R|/A|.R|/Some.foo|(Int(-1))
-            lval res3: R|ft<kotlin/Array<ft<kotlin/String, kotlin/String?>!>, kotlin/Array<out ft<kotlin/String, kotlin/String?>!>?>!| = this@R|/A|.R|/Some.bar|(R|kotlin/intArrayOf|(vararg(Int(0), Int(2), Int(-2))))
+            lval res3: R|ft<@FlexibleNullability kotlin/Array<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>, kotlin/Array<out ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?>!| = this@R|/A|.R|/Some.bar|(R|kotlin/intArrayOf|(vararg(Int(0), Int(2), Int(-2))))
         }
 
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/FunctionTypeInJava.txt

@@ -1,14 +1,14 @@
 FILE: main.kt
     public final fun main(): R|kotlin/Unit| {
-        Q|JavaClass|.R|/JavaClass.foo1|(<L> = foo1@fun <anonymous>(): R|ft<kotlin/Int, kotlin/Int?>!| {
+        Q|JavaClass|.R|/JavaClass.foo1|(<L> = foo1@fun <anonymous>(): R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!| {
             ^ Int(123)
         }
         )
-        Q|JavaClass|.R|/JavaClass.foo2|(<L> = foo2@fun <anonymous>(it: R|ft<kotlin/Int, kotlin/Int?>!|): R|ft<kotlin/String, kotlin/String?>!| {
+        Q|JavaClass|.R|/JavaClass.foo2|(<L> = foo2@fun <anonymous>(it: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!|): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| {
             ^ R|<local>/it|.R|kotlin/Int.plus|(Int(2)).R|kotlin/Any.toString|()
         }
         )
-        Q|JavaClass|.R|/JavaClass.foo2|(foo2@fun <anonymous>(it: R|ft<kotlin/Int, kotlin/Int?>!|): R|ft<kotlin/String, kotlin/String?>!| {
+        Q|JavaClass|.R|/JavaClass.foo2|(foo2@fun <anonymous>(it: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!|): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| {
             ^ R|<local>/it|.R|kotlin/Int.plus|(Int(3)).R|kotlin/Any.toString|()
         }
         )
@@ -17,7 +17,7 @@ FILE: main.kt
         }
 
         Q|JavaClass|.R|/JavaClass.foo2|(R|<local>/y|)
-        Q|JavaClass|.R|/JavaClass.foo3|<R|ft<kotlin/Int, kotlin/Int?>!|>(foo3@fun <anonymous>(it: R|ft<kotlin/Int, kotlin/Int?>!|): R|ft<kotlin/String, kotlin/String?>!| {
+        Q|JavaClass|.R|/JavaClass.foo3|<R|ft<kotlin/Int, kotlin/Int?>!|>(foo3@fun <anonymous>(it: R|ft<kotlin/Int, kotlin/Int?>!|): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| {
             ^ R|<local>/it|.R|kotlin/Int.plus|(Int(4)).R|kotlin/Any.toString|()
         }
         , Int(5))

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/JavaGetPrefixConflict.txt

@@ -1,8 +1,8 @@
 FILE: Test.kt
     public final fun test(): R|kotlin/Unit| {
         lval jc: R|JavaClass| = R|/JavaClass.JavaClass|()
-        lval result: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/jc|.R|/JavaClass.text|
+        lval result: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/jc|.R|/JavaClass.text|
     }
     public final fun otherTest(jc: R|JavaClass|): R|kotlin/Unit| {
-        lval result: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/jc|.R|/JavaClass.text|
+        lval result: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/jc|.R|/JavaClass.text|
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/JavaSyntheticProperty.txt

@@ -1,3 +1,3 @@
 FILE: test.kt
-    public final val x: R|ft<kotlin/String, kotlin/String?>!| = R|/JavaClass.JavaClass|().R|/JavaClass.foo|
+    public final val x: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|/JavaClass.JavaClass|().R|/JavaClass.foo|
-        public get(): R|ft<kotlin/String, kotlin/String?>!|
+        public get(): R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/KJKInheritanceGeneric.txt

@@ -16,7 +16,7 @@ FILE: K2.kt
         }
 
         public final fun bar(): R|kotlin/Unit| {
-            this@R|/K2|.R|SubstitutionOverride</J1.foo: R|ft<kotlin/Int, kotlin/Int?>!|>|(Int(1))
+            this@R|/K2|.R|SubstitutionOverride</J1.foo: R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!|>|(Int(1))
             this@R|/K2|.R|/J1.baz|()
         }
 

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/KotlinClassParameterGeneric.txt

@@ -7,7 +7,7 @@ FILE: K1.kt
     }
 FILE: K2.kt
     public final fun main(): R|kotlin/Unit| {
-        Q|JavaClass|.R|/JavaClass.baz|(R|/KotlinClass.KotlinClass|<R|ft<kotlin/Int, kotlin/Int?>!|>())
+        Q|JavaClass|.R|/JavaClass.baz|(R|/KotlinClass.KotlinClass|<R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!|>())
         Q|JavaClass|.R|/JavaClass.baz|(R|/KotlinClass.KotlinClass|<R|kotlin/Int|>())
         Q|JavaClass|.<Inapplicable(INAPPLICABLE): /JavaClass.baz>#(R|/KotlinClass.KotlinClass|<R|kotlin/String|>())
         Q|JavaClass|.<Inapplicable(INAPPLICABLE): /JavaClass.baz>#(String())

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/LoggerInstance.txt

@@ -1,6 +1,6 @@
 FILE: test.kt
     public final fun test(): R|kotlin/Unit| {
-        lval logger: R|ft<Logger, Logger?>!| = Q|Logger|.R|/Logger.getInstance|(String(test))
+        lval logger: R|ft<@FlexibleNullability Logger, Logger?>!| = Q|Logger|.R|/Logger.getInstance|(String(test))
     }
     public final class MyTest : R|kotlin/Any| {
         public constructor(): R|MyTest| {
@@ -10,7 +10,7 @@ FILE: test.kt
         private final val klass: R|java/lang/Class<MyTest>| = <getClass>(this@R|/MyTest|).R|kotlin/jvm/java|<R|MyTest|>
             private get(): R|java/lang/Class<MyTest>|
 
-        private final val logger: R|ft<Logger, Logger?>!| = Q|Logger|.R|/Logger.getInstance|(this@R|/MyTest|.R|/MyTest.klass|)
+        private final val logger: R|ft<@FlexibleNullability Logger, Logger?>!| = Q|Logger|.R|/Logger.getInstance|(this@R|/MyTest|.R|/MyTest.klass|)
-            private get(): R|ft<Logger, Logger?>!|
+            private get(): R|ft<@FlexibleNullability Logger, Logger?>!|
 
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/MapEntry.txt

@@ -7,7 +7,7 @@ FILE: main.kt
     }
     public final fun test(): R|kotlin/Unit| {
         lval b: R|MyMapEntry| = R|/MyMapEntry.MyMapEntry|()
-        lval key: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/b|.R|/Test.MapEntryImpl.key|
+        lval key: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/b|.R|/Test.MapEntryImpl.key|
-        lval value: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/b|.R|/Test.MapEntryImpl.value|
+        lval value: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/b|.R|/Test.MapEntryImpl.value|
         R|<local>/b|.R|/Test.MapEntryImpl.setValue|(Null(null))
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/MyException.txt

@@ -8,15 +8,15 @@ FILE: test.kt
     public final fun test(e: R|MyException|, stream: R|java/io/PrintStream|): R|kotlin/Unit| {
         R|<local>/e|.R|java/lang/Throwable.printStackTrace|()
         R|<local>/e|.R|java/lang/Throwable.printStackTrace|(R|<local>/stream|)
-        lval result: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/e|.R|java/lang/Throwable.getLocalizedMessage|()
+        lval result: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/e|.R|java/lang/Throwable.getLocalizedMessage|()
     }
     public final fun test(e: R|YourException|, stream: R|java/io/PrintStream|): R|kotlin/Unit| {
         R|<local>/e|.R|java/lang/Throwable.printStackTrace|()
         R|<local>/e|.R|java/lang/Throwable.printStackTrace|(R|<local>/stream|)
-        lval result: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/e|.R|java/lang/Throwable.getLocalizedMessage|()
+        lval result: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/e|.R|java/lang/Throwable.getLocalizedMessage|()
     }
     public final fun test(e: R|kotlin/Exception|, stream: R|java/io/PrintStream|): R|kotlin/Unit| {
         R|<local>/e|.R|java/lang/Throwable.printStackTrace|()
         R|<local>/e|.R|java/lang/Throwable.printStackTrace|(R|<local>/stream|)
-        lval result: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/e|.R|java/lang/Throwable.getLocalizedMessage|()
+        lval result: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/e|.R|java/lang/Throwable.getLocalizedMessage|()
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/MyIterable.txt

@@ -2,11 +2,11 @@ FILE: test.kt
     public abstract interface UseIterable : R|MyIterable<kotlin/String>| {
         public open fun test(): R|kotlin/Unit| {
             lval it: R|kotlin/collections/MutableIterator<ft<kotlin/String, kotlin/String?>!>| = this@R|/UseIterable|.R|SubstitutionOverride</UseIterable.iterator: R|kotlin/collections/MutableIterator<ft<kotlin/String, kotlin/String?>!>|>|()
-            lval split: R|java/util/Spliterator<ft<kotlin/String, kotlin/String?>!>| = this@R|/UseIterable|.R|SubstitutionOverride</UseIterable.spliterator: R|java/util/Spliterator<ft<kotlin/String, kotlin/String?>!>|>|()
+            lval split: R|@FlexibleNullability java/util/Spliterator<ft<kotlin/String, kotlin/String?>!>| = this@R|/UseIterable|.R|SubstitutionOverride</UseIterable.spliterator: R|@FlexibleNullability java/util/Spliterator<ft<kotlin/String, kotlin/String?>!>|>|()
         }
 
     }
     public final fun test(some: R|kotlin/collections/Iterable<kotlin/String>|): R|kotlin/Unit| {
         lval it: R|kotlin/collections/Iterator<kotlin/String>| = R|<local>/some|.R|SubstitutionOverride<kotlin/collections/Iterable.iterator: R|kotlin/collections/Iterator<kotlin/String>|>|()
-        lval split: R|java/util/Spliterator<ft<kotlin/String, kotlin/String?>!>| = R|<local>/some|.R|SubstitutionOverride<kotlin/collections/Iterable.spliterator: R|java/util/Spliterator<ft<kotlin/String, kotlin/String?>!>|>|()
+        lval split: R|@FlexibleNullability java/util/Spliterator<ft<kotlin/String, kotlin/String?>!>| = R|<local>/some|.R|SubstitutionOverride<kotlin/collections/Iterable.spliterator: R|@FlexibleNullability java/util/Spliterator<ft<kotlin/String, kotlin/String?>!>|>|()
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/MyMap.txt

@@ -1,20 +1,20 @@
 FILE: test.kt
     public final fun test(map: R|MyMap|): R|kotlin/Unit| {
-        lval result: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/map|.R|kotlin/collections/getOrPut|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<kotlin/String, kotlin/String?>!|>(String(key), <L> = getOrPut@fun <anonymous>(): R|kotlin/String| <kind=UNKNOWN>  {
+        lval result: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/map|.R|kotlin/collections/getOrPut|<R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>(String(key), <L> = getOrPut@fun <anonymous>(): R|kotlin/String| <kind=UNKNOWN>  {
             ^ String(value)
         }
         )
-        lval otherResult: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/map|.R|SubstitutionOverride</MyMap.getOrDefault: R|ft<kotlin/String, kotlin/String?>!|>|(String(key), String(value))
+        lval otherResult: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/map|.R|SubstitutionOverride</MyMap.getOrDefault: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>|(String(key), String(value))
-        lval anotherResult: R|kotlin/String?| = R|<local>/map|.R|SubstitutionOverride</MyMap.replace: R|kotlin/String?|>|(String(key), String(value))
+        lval anotherResult: R|@FlexibleNullability kotlin/String?| = R|<local>/map|.R|SubstitutionOverride</MyMap.replace: R|@FlexibleNullability kotlin/String?|>|(String(key), String(value))
-        R|<local>/map|.R|SubstitutionOverride</MyMap.forEach: R|kotlin/Unit|>|(<L> = forEach@fun <anonymous>(key: R|ft<kotlin/String, kotlin/String?>!|, value: R|ft<kotlin/String, kotlin/String?>!|): R|kotlin/Unit| {
+        R|<local>/map|.R|SubstitutionOverride</MyMap.forEach: R|kotlin/Unit|>|(<L> = forEach@fun <anonymous>(key: R|ft<@FlexibleNullability kotlin/String, @FlexibleNullability kotlin/String?>!|, value: R|ft<@FlexibleNullability kotlin/String, @FlexibleNullability kotlin/String?>!|): R|kotlin/Unit| {
             R|kotlin/io/println|(<strcat>(R|<local>/key|.R|kotlin/Any.toString|(), String(: ), R|<local>/value|.R|kotlin/Any.toString|()))
             R|<local>/key|.R|kotlin/String.length|
             R|<local>/value|.R|kotlin/String.length|
         }
         )
-        R|<local>/map|.R|kotlin/collections/forEach|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<kotlin/String, kotlin/String?>!|>(<L> = forEach@fun <anonymous>(<destruct>: R|kotlin/collections/Map.Entry<ft<kotlin/String, kotlin/String?>!, ft<kotlin/String, kotlin/String?>!>|): R|kotlin/Unit| <kind=UNKNOWN>  {
+        R|<local>/map|.R|kotlin/collections/forEach|<R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>(<L> = forEach@fun <anonymous>(<destruct>: R|kotlin/collections/Map.Entry<ft<@FlexibleNullability kotlin/String, kotlin/String?>!, ft<@FlexibleNullability kotlin/String, kotlin/String?>!>|): R|kotlin/Unit| <kind=UNKNOWN>  {
-            lval key: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/<destruct>|.R|kotlin/collections/component1|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<kotlin/String, kotlin/String?>!|>()
+            lval key: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/<destruct>|.R|kotlin/collections/component1|<R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>()
-            lval value: R|ft<kotlin/String, kotlin/String?>!| = R|<local>/<destruct>|.R|kotlin/collections/component2|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<kotlin/String, kotlin/String?>!|>()
+            lval value: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|<local>/<destruct>|.R|kotlin/collections/component2|<R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>()
             R|kotlin/io/println|(<strcat>(R|<local>/key|.R|kotlin/Any.toString|(), String(: ), R|<local>/value|.R|kotlin/Any.toString|()))
             R|<local>/key|.R|kotlin/String.length|
             R|<local>/value|.R|kotlin/String.length|

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/StaticFromBaseClass.txt

@@ -1,5 +1,5 @@
 FILE: main.kt
     public final fun test(): R|kotlin/Unit| {
-        lval project: R|ft<kotlin/String, kotlin/String?>!| = Q|PlatformDataKeys|.R|/CommonDataKeys.PROJECT|
+        lval project: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = Q|PlatformDataKeys|.R|/CommonDataKeys.PROJECT|
-        lval member: R|ft<kotlin/String, kotlin/String?>!| = R|/PlatformDataKeys.PlatformDataKeys|().R|/CommonDataKeys.MEMBER|
+        lval member: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!| = R|/PlatformDataKeys.PlatformDataKeys|().R|/CommonDataKeys.MEMBER|
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/SyntheticWithForEach.txt

@@ -1,13 +1,13 @@
 FILE: test.kt
     public final fun <D : R|kotlin/Any|> R|Call<D>|.testForEach(): R|kotlin/Unit| {
-        this@R|/testForEach|.R|/Call.arguments|.R|SubstitutionOverride<kotlin/collections/MutableMap.forEach: R|kotlin/Unit|>|(<L> = forEach@fun <anonymous>(key: R|ft<kotlin/String, kotlin/String?>!|, value: R|ft<kotlin/String, kotlin/String?>!|): R|kotlin/Unit| {
+        this@R|/testForEach|.R|/Call.arguments|.R|SubstitutionOverride<kotlin/collections/MutableMap.forEach: R|kotlin/Unit|>|(<L> = forEach@fun <anonymous>(key: R|ft<@FlexibleNullability kotlin/String, @FlexibleNullability kotlin/String?>!|, value: R|ft<@FlexibleNullability kotlin/String, @FlexibleNullability kotlin/String?>!|): R|kotlin/Unit| {
             R|<local>/key|.R|kotlin/String.length|
             R|<local>/value|.R|kotlin/String.length|
         }
         )
-        this@R|/testForEach|.R|/Call.arguments|.R|kotlin/collections/forEach|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<kotlin/String, kotlin/String?>!|>(<L> = forEach@fun <anonymous>(it: R|kotlin/collections/Map.Entry<ft<kotlin/String, kotlin/String?>!, ft<kotlin/String, kotlin/String?>!>|): R|kotlin/Unit| <kind=UNKNOWN>  {
+        this@R|/testForEach|.R|/Call.arguments|.R|kotlin/collections/forEach|<R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>(<L> = forEach@fun <anonymous>(it: R|kotlin/collections/Map.Entry<ft<@FlexibleNullability kotlin/String, kotlin/String?>!, ft<@FlexibleNullability kotlin/String, kotlin/String?>!>|): R|kotlin/Unit| <kind=UNKNOWN>  {
-            R|<local>/it|.R|SubstitutionOverride<kotlin/collections/Map.Entry.key: R|ft<kotlin/String, kotlin/String?>!|>|.R|kotlin/String.length|
+            R|<local>/it|.R|SubstitutionOverride<kotlin/collections/Map.Entry.key: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>|.R|kotlin/String.length|
-            R|<local>/it|.R|SubstitutionOverride<kotlin/collections/Map.Entry.value: R|ft<kotlin/String, kotlin/String?>!|>|.R|kotlin/String.length|
+            R|<local>/it|.R|SubstitutionOverride<kotlin/collections/Map.Entry.value: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>|.R|kotlin/String.length|
         }
         )
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/capturedFlexible.txt

@@ -1,4 +1,4 @@
 FILE: capturedFlexible.kt
     public final fun foo(z: R|java/util/zip/ZipFile|): R|kotlin/Unit| {
-        R|<local>/z|.R|java/util/zip/ZipFile.entries|().R|kotlin/sequences/asSequence|<R|ft<java/util/zip/ZipEntry, java/util/zip/ZipEntry?>!|>()
+        R|<local>/z|.R|java/util/zip/ZipFile.entries|().R|kotlin/sequences/asSequence|<R|ft<@FlexibleNullability java/util/zip/ZipEntry, java/util/zip/ZipEntry?>!|>()
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/complexFlexibleInference.txt

@@ -1,4 +1,4 @@
 FILE: main.kt
     public final fun bar(bindingContext: R|BindingContext|): R|kotlin/Unit| {
-        R|<local>/bindingContext|.R|/BindingContext.get|<R|ft<kotlin/String, kotlin/String?>!|, R|ft<kotlin/Double, kotlin/Double?>!|>(Q|Slices|.R|/Slices.X|, R|<local>/bindingContext|.R|/BindingContext.get|<R|ft<kotlin/Int, kotlin/Int?>!|, R|ft<kotlin/String, kotlin/String?>!|>(Q|Slices|.R|/Slices.Y|, Int(1)))
+        R|<local>/bindingContext|.R|/BindingContext.get|<R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, R|ft<@FlexibleNullability kotlin/Double, kotlin/Double?>!|>(Q|Slices|.R|/Slices.X|, R|<local>/bindingContext|.R|/BindingContext.get|<R|ft<@FlexibleNullability kotlin/Int, kotlin/Int?>!|, R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|>(Q|Slices|.R|/Slices.Y|, Int(1)))
     }

compiler/fir/analysis-tests/testData/resolveWithStdlib/j+k/flexibleTypeAliases.txt

@@ -4,5 +4,5 @@ FILE: main.kt
     public final typealias ImmutableLinkedHashSet<E> = R|imm/LinkedHashSet<E>|
     private final typealias ImmutableMultimap<K, V> = R|ImmutableMap<K, ImmutableSet<V>>|
     private final fun <K, V> R|ImmutableMultimap<K, V>|.put(key: R|K|, value: R|V|): R|kotlin/Unit| {
-        this@R|/put|.R|SubstitutionOverride<imm/Map.get: R|ft<imm/Option<ft<ImmutableSet<V>, ImmutableSet<V>?>!>, imm/Option<ft<ImmutableSet<V>, ImmutableSet<V>?>!>?>!|>|(R|<local>/key|).R|SubstitutionOverride<imm/Option.getOrElse: R|ft<ImmutableSet<V>, ImmutableSet<V>?>!|>|(Q|ImmutableLinkedHashSet|.R|imm/LinkedHashSet.empty|<R|ft<V, V?>!|>())
+        this@R|/put|.R|SubstitutionOverride<imm/Map.get: R|ft<@FlexibleNullability imm/Option<ft<ImmutableSet<V>, ImmutableSet<V>?>!>, imm/Option<ft<ImmutableSet<V>, ImmutableSet<V>?>!>?>!|>|(R|<local>/key|).R|SubstitutionOverride<imm/Option.getOrElse: R|ft<ImmutableSet<V>, ImmutableSet<V>?>!|>|(Q|ImmutableLinkedHashSet|.R|imm/LinkedHashSet.empty|<R|ft<V, V?>!|>())
     }

compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/CompilerConeAttributes.kt

@@ -59,6 +59,18 @@ object CompilerConeAttributes {
         override fun toString(): String = "@ExtensionFunctionType"
     }
 
+    object FlexibleNullability : ConeAttribute<FlexibleNullability>() {
+        val ANNOTATION_CLASS_ID = ClassId(FqName("kotlin.internal.ir"), Name.identifier("FlexibleNullability"))
+
+        override fun union(other: FlexibleNullability?): FlexibleNullability? = other
+        override fun intersect(other: FlexibleNullability?): FlexibleNullability? = this
+        override fun isSubtypeOf(other: FlexibleNullability?): Boolean = true
+
+        override val key: KClass<out FlexibleNullability> = FlexibleNullability::class
+
+        override fun toString(): String = "@FlexibleNullability"
+    }
+
     object UnsafeVariance : ConeAttribute<UnsafeVariance>() {
         val ANNOTATION_CLASS_ID = ClassId(FqName("kotlin"), Name.identifier("UnsafeVariance"))
 
@@ -76,6 +88,7 @@ val ConeAttributes.exact: CompilerConeAttributes.Exact? by ConeAttributes.attrib
 val ConeAttributes.noInfer: CompilerConeAttributes.NoInfer? by ConeAttributes.attributeAccessor<CompilerConeAttributes.NoInfer>()
 val ConeAttributes.enhancedNullability: CompilerConeAttributes.EnhancedNullability? by ConeAttributes.attributeAccessor<CompilerConeAttributes.EnhancedNullability>()
 val ConeAttributes.extensionFunctionType: CompilerConeAttributes.ExtensionFunctionType? by ConeAttributes.attributeAccessor<CompilerConeAttributes.ExtensionFunctionType>()
+val ConeAttributes.flexibleNullability: CompilerConeAttributes.FlexibleNullability? by ConeAttributes.attributeAccessor<CompilerConeAttributes.FlexibleNullability>()
 val ConeAttributes.unsafeVarianceType: CompilerConeAttributes.UnsafeVariance? by ConeAttributes.attributeAccessor<CompilerConeAttributes.UnsafeVariance>()
 
 val ConeKotlinType.hasEnhancedNullability: Boolean
@@ -83,3 +96,6 @@ val ConeKotlinType.hasEnhancedNullability: Boolean
 
 val ConeKotlinType.isExtensionFunctionType: Boolean
     get() = attributes.extensionFunctionType != null
+
+val ConeKotlinType.hasFlexibleNullability: Boolean
+    get() = attributes.flexibleNullability != null

compiler/fir/cones/src/org/jetbrains/kotlin/fir/types/ConeAttributes.kt

@@ -34,6 +34,7 @@ class ConeAttributes private constructor(attributes: List<ConeAttribute<*>>) : A
         }
 
         val Empty: ConeAttributes = ConeAttributes(emptyList())
+        val WithFlexibleNullability: ConeAttributes = ConeAttributes(listOf(CompilerConeAttributes.FlexibleNullability))
 
         fun create(attributes: List<ConeAttribute<*>>): ConeAttributes {
             return if (attributes.isEmpty()) {
@@ -48,8 +49,17 @@ class ConeAttributes private constructor(attributes: List<ConeAttribute<*>>) : A
         for (attribute in attributes) {
             registerComponent(attribute.key, attribute)
         }
+        assert(!hasEnhancedNullability || !hasFlexibleNullability) {
+            "It doesn't make sense to have @EnhancedNullability and @FlexibleNullability at the same time."
+        }
     }
 
+    val hasEnhancedNullability: Boolean
+        get() = enhancedNullability != null
+
+    val hasFlexibleNullability: Boolean
+        get() = flexibleNullability != null
+
     fun union(other: ConeAttributes): ConeAttributes {
         return perform(other) { this.union(it) }
     }
@@ -58,6 +68,13 @@ class ConeAttributes private constructor(attributes: List<ConeAttribute<*>>) : A
         return perform(other) { this.intersect(it) }
     }
 
+    fun intersectUnless(other: ConeAttributes, predicate: (ConeAttributes) -> Boolean): ConeAttributes {
+        return if (predicate.invoke(this))
+            this
+        else
+            perform(other) { this.intersect(it) }
+    }
+
     override fun iterator(): Iterator<ConeAttribute<*>> {
         return arrayMap.iterator()
     }

compiler/fir/fir2ir/jvm-backend/src/org/jetbrains/kotlin/fir/backend/jvm/Fir2IrJvmSpecialAnnotationSymbolProvider.kt

@@ -10,11 +10,15 @@ import org.jetbrains.kotlin.descriptors.ClassKind
 import org.jetbrains.kotlin.fir.backend.Fir2IrSpecialSymbolProvider
 import org.jetbrains.kotlin.ir.builders.declarations.addConstructor
 import org.jetbrains.kotlin.ir.builders.declarations.buildClass
+import org.jetbrains.kotlin.ir.declarations.IrClass
+import org.jetbrains.kotlin.ir.declarations.IrDeclarationParent
 import org.jetbrains.kotlin.ir.declarations.impl.IrExternalPackageFragmentImpl
+import org.jetbrains.kotlin.ir.descriptors.IrBuiltIns
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.symbols.impl.DescriptorlessExternalPackageFragmentSymbol
 import org.jetbrains.kotlin.load.java.JvmAnnotationNames
 import org.jetbrains.kotlin.name.ClassId
+import org.jetbrains.kotlin.name.Name
 
 class Fir2IrJvmSpecialAnnotationSymbolProvider : Fir2IrSpecialSymbolProvider() {
 
@@ -25,21 +29,35 @@ class Fir2IrJvmSpecialAnnotationSymbolProvider : Fir2IrSpecialSymbolProvider() {
         )
     }
 
-    override fun getClassSymbolById(id: ClassId): IrClassSymbol? {
+    private val kotlinInternalIrPackage by lazy {
-        if (id != ENHANCED_NULLABILITY_ID) return null
+        IrExternalPackageFragmentImpl(
-        return components.irFactory.buildClass {
+            DescriptorlessExternalPackageFragmentSymbol(),
+            FLEXIBLE_NULLABILITY_ID.packageFqName
+        )
+    }
+
+    override fun getClassSymbolById(id: ClassId): IrClassSymbol? =
+        when (id) {
+            ENHANCED_NULLABILITY_ID -> id.toIrClass(kotlinJvmInternalPackage).symbol
+            FLEXIBLE_NULLABILITY_ID -> id.toIrClass(kotlinInternalIrPackage).symbol
+            else -> null
+        }
+
+    private fun ClassId.toIrClass(parent: IrDeclarationParent): IrClass =
+        components.irFactory.buildClass {
             kind = ClassKind.ANNOTATION_CLASS
-            name = ENHANCED_NULLABILITY_ID.shortClassName
+            name = shortClassName
         }.apply {
             createImplicitParameterDeclarationWithWrappedDescriptor()
-            this.parent = kotlinJvmInternalPackage
+            this.parent = parent
             addConstructor {
                 isPrimary = true
             }
-        }.symbol
+        }
-    }
 
     companion object {
         private val ENHANCED_NULLABILITY_ID = ClassId.topLevel(JvmAnnotationNames.ENHANCED_NULLABILITY_ANNOTATION)
+        private val FLEXIBLE_NULLABILITY_ID =
+            ClassId.topLevel(IrBuiltIns.KOTLIN_INTERNAL_IR_FQN.child(Name.identifier("FlexibleNullability")))
     }
 }

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrBuiltIns.kt

@@ -37,6 +37,13 @@ class Fir2IrBuiltIns(
     internal fun enhancedNullabilityAnnotationConstructorCall(): IrConstructorCall? =
         enhancedNullabilityAnnotationSymbol?.toConstructorCall()
 
+    private val flexibleNullabilityAnnotationSymbol by lazy {
+        annotationSymbolById(CompilerConeAttributes.FlexibleNullability.ANNOTATION_CLASS_ID)
+    }
+
+    internal fun flexibleNullabilityAnnotationConstructorCall(): IrConstructorCall? =
+        flexibleNullabilityAnnotationSymbol?.toConstructorCall()
+
     private fun annotationSymbolById(id: ClassId): IrClassSymbol? =
         provider?.getClassSymbolById(id) ?: session.firSymbolProvider.getClassLikeSymbolByFqName(id)?.toSymbol(
             session, classifierStorage, ConversionTypeContext.DEFAULT

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrTypeConverter.kt

@@ -99,6 +99,11 @@ class Fir2IrTypeConverter(
                         typeAnnotations += it
                     }
                 }
+                if (hasFlexibleNullability) {
+                    builtIns.flexibleNullabilityAnnotationConstructorCall()?.let {
+                        typeAnnotations += it
+                    }
+                }
                 IrSimpleTypeImpl(
                     irSymbol, !typeContext.definitelyNotNull && this.isMarkedNullable,
                     fullyExpandedType(session).typeArguments.map { it.toIrTypeArgument(typeContext) },

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaUtils.kt

@@ -197,7 +197,11 @@ private fun ClassId.toConeFlexibleType(
     typeArgumentsForUpper: Array<ConeTypeProjection> = typeArguments,
     attributes: ConeAttributes = ConeAttributes.Empty
 ) = ConeFlexibleType(
-    toConeKotlinType(typeArguments, isNullable = false, attributes),
+    toConeKotlinType(
+        typeArguments,
+        isNullable = false,
+        attributes.intersectUnless(ConeAttributes.WithFlexibleNullability) { it.hasEnhancedNullability }
+    ),
     toConeKotlinType(typeArgumentsForUpper, isNullable = true, attributes)
 )
 
@@ -233,7 +237,15 @@ private fun JavaClassifierType.toConeKotlinTypeWithoutEnhancement(
             attributes = attributes
         )
 
-    return if (isRaw) ConeRawType(lowerBound, upperBound) else ConeFlexibleType(lowerBound, upperBound)
+    return if (isRaw)
+        ConeRawType(lowerBound, upperBound)
+    else
+        ConeFlexibleType(
+            lowerBound.withAttributes(
+                lowerBound.attributes.intersectUnless(ConeAttributes.WithFlexibleNullability) { it.hasEnhancedNullability }
+            ),
+            upperBound
+        )
 }
 
 private fun computeRawProjection(
@@ -303,7 +315,9 @@ private fun getErasedVersionOfFirstUpperBound(
             if (firstUpperBound.upperBound is ConeTypeParameterType) {
                 // Avoid exponential complexity
                 ConeFlexibleType(
-                    lowerBound,
+                    lowerBound.withAttributes(
+                        lowerBound.attributes.intersectUnless(ConeAttributes.WithFlexibleNullability) { it.hasEnhancedNullability }
+                    ),
                     lowerBound.withNullability(ConeNullability.NULLABLE)
                 )
             } else {

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/enhancement/javaTypeUtils.kt

@@ -88,22 +88,29 @@ private fun ConeKotlinType.enhanceConeKotlinType(
 ): ConeKotlinType {
     return when (this) {
         is ConeFlexibleType -> {
+            val needsFlexibleNullabilityAttribute = lowerBound.nullability != upperBound.nullability && !lowerBound.hasEnhancedNullability
             val lowerResult = lowerBound.enhanceInflexibleType(
-                session, TypeComponentPosition.FLEXIBLE_LOWER, qualifiers, index
+                session, TypeComponentPosition.FLEXIBLE_LOWER, qualifiers, index,
+                attributes = if (needsFlexibleNullabilityAttribute)
+                    lowerBound.attributes.intersect(ConeAttributes.WithFlexibleNullability)
+                else
+                    lowerBound.attributes
             )
             val upperResult = upperBound.enhanceInflexibleType(
-                session, TypeComponentPosition.FLEXIBLE_UPPER, qualifiers, index
+                session, TypeComponentPosition.FLEXIBLE_UPPER, qualifiers, index, upperBound.attributes
             )
 
             when {
-                lowerResult === lowerBound && upperResult === upperBound -> this
+                !needsFlexibleNullabilityAttribute && lowerResult === lowerBound && upperResult === upperBound -> this
                 this is ConeRawType -> ConeRawType(lowerResult, upperResult)
                 else -> coneFlexibleOrSimpleType(
                     session, lowerResult, upperResult, isNotNullTypeParameter = qualifiers(index).isNotNullTypeParameter
                 )
             }
         }
-        is ConeSimpleKotlinType -> enhanceInflexibleType(session, TypeComponentPosition.INFLEXIBLE, qualifiers, index)
+        is ConeSimpleKotlinType -> enhanceInflexibleType(
+            session, TypeComponentPosition.INFLEXIBLE, qualifiers, index, attributes
+        )
         else -> this
     }
 }
@@ -158,7 +165,8 @@ private fun ConeKotlinType.enhanceInflexibleType(
     session: FirSession,
     position: TypeComponentPosition,
     qualifiers: IndexedJavaTypeQualifiers,
-    index: Int
+    index: Int,
+    attributes: ConeAttributes = this.attributes
 ): ConeKotlinType {
     require(this !is ConeFlexibleType) {
         "$this should not be flexible"
@@ -198,7 +206,7 @@ private fun ConeKotlinType.enhanceInflexibleType(
 
     if (!wereChangesInArgs && originalTag == enhancedTag && enhancedNullability == isNullable) return this
 
-    val enhancedType = enhancedTag.constructType(enhancedArguments, enhancedNullability)
+    val enhancedType = enhancedTag.constructType(enhancedArguments, enhancedNullability, attributes)
 
     // TODO: why all of these is needed
 //    val enhancement = if (effectiveQualifiers.isNotNullTypeParameter) NotNullTypeParameter(enhancedType) else enhancedType

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/scopes/JavaClassMembersEnhancementScope.kt

@@ -104,7 +104,14 @@ class JavaClassMembersEnhancementScope(
                                 emptyArray(), valueParameter.returnTypeRef.isMarkedNullable == true
                             )
                             if (valueParameter.returnTypeRef.coneType is ConeFlexibleType) {
-                                ConeFlexibleType(type, type.withNullability(ConeNullability.NULLABLE))
+                                ConeFlexibleType(
+                                    type.withAttributes(
+                                        type.attributes.intersectUnless(ConeAttributes.WithFlexibleNullability) {
+                                            it.hasEnhancedNullability
+                                        }
+                                    ),
+                                    type.withNullability(ConeNullability.NULLABLE)
+                                )
                             } else {
                                 type
                             }
@@ -129,8 +136,8 @@ class JavaClassMembersEnhancementScope(
                 newParameterTypes = valueParameters.zip(newParameterTypes).map { (valueParameter, newType) ->
                     newType ?: valueParameter.returnTypeRef.coneType
                 },
-                    newDispatchReceiverType = dispatchReceiverType,
+                newDispatchReceiverType = dispatchReceiverType,
-                )
+            )
 
         }
         return this

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/types/TypeUtils.kt

@@ -105,8 +105,12 @@ fun ConeTypeContext.hasNullableSuperType(type: ConeKotlinType): Boolean {
     return false
 }
 
-fun <T : ConeKotlinType> T.withNullability(nullability: ConeNullability, typeContext: ConeInferenceContext? = null): T {
+fun <T : ConeKotlinType> T.withNullability(
-    if (this.nullability == nullability) {
+    nullability: ConeNullability,
+    typeContext: ConeInferenceContext? = null,
+    attributes: ConeAttributes = this.attributes,
+): T {
+    if (this.nullability == nullability && this.attributes == attributes) {
         return this
     }
 
@@ -188,6 +192,9 @@ fun FirTypeRef.isUnsafeVarianceType(session: FirSession): Boolean {
 fun FirTypeRef.hasEnhancedNullability(): Boolean =
     coneTypeSafe<ConeKotlinType>()?.hasEnhancedNullability == true
 
+fun FirTypeRef.hasFlexibleNullability(): Boolean =
+    coneTypeSafe<ConeKotlinType>()?.hasFlexibleNullability == true
+
 fun FirTypeRef.withoutEnhancedNullability(): FirTypeRef {
     require(this is FirResolvedTypeRef)
     if (!hasEnhancedNullability()) return this

compiler/fir/tree/src/org/jetbrains/kotlin/fir/types/TypeConstructionUtils.kt

@@ -15,11 +15,12 @@ import org.jetbrains.kotlin.name.ClassId
 
 fun ConeClassifierLookupTag.constructType(
     typeArguments: Array<out ConeTypeProjection>,
-    isNullable: Boolean
+    isNullable: Boolean,
+    attributes: ConeAttributes = ConeAttributes.Empty
 ): ConeLookupTagBasedType {
     return when (this) {
-        is ConeTypeParameterLookupTag -> ConeTypeParameterTypeImpl(this, isNullable)
+        is ConeTypeParameterLookupTag -> ConeTypeParameterTypeImpl(this, isNullable, attributes)
-        is ConeClassLikeLookupTag -> this.constructClassType(typeArguments, isNullable)
+        is ConeClassLikeLookupTag -> this.constructClassType(typeArguments, isNullable, attributes)
         else -> error("! ${this::class}")
     }
 }

compiler/testData/diagnostics/testsWithStdLib/inference/recursiveFlexibleAssertions.fir.kt

@@ -75,5 +75,5 @@ fun test() {
     }
     // TODO: FIR
     // {AbstractAssert<*, out Any!>! & EnumerableAssert<*, {Comparable<*> & java.io.Serializable!}>!} with unfolded flexible nullability
-    <!DEBUG_INFO_EXPRESSION_TYPE("AbstractAssert<*, out ERROR CLASS: CST(ERROR CLASS: Unexpected classifier: null, kotlin/String..ERROR CLASS: CST(ERROR CLASS: Unexpected classifier: null, kotlin/String?!> & EnumerableAssert<*, out kotlin.Comparable<kotlin.String & kotlin.Char> & java.io.Serializable..kotlin.Comparable<kotlin.String & kotlin.Char>? & java.io.Serializable?>..AbstractAssert<*, out ERROR CLASS: CST(ERROR CLASS: Unexpected classifier: null, kotlin/String..ERROR CLASS: CST(ERROR CLASS: Unexpected classifier: null, kotlin/String?!>? & EnumerableAssert<*, out kotlin.Comparable<kotlin.String & kotlin.Char> & java.io.Serializable..kotlin.Comparable<kotlin.String & kotlin.Char>? & java.io.Serializable?>?")!>assertion<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("AbstractAssert<*, out ERROR CLASS: CST(ERROR CLASS: Unexpected classifier: null, @FlexibleNullability kotlin/String..ERROR CLASS: CST(ERROR CLASS: Unexpected classifier: null, @FlexibleNullability kotlin/String?!> & EnumerableAssert<*, out kotlin.Comparable<kotlin.String & kotlin.Char> & java.io.Serializable..kotlin.Comparable<kotlin.String & kotlin.Char>? & java.io.Serializable?>..AbstractAssert<*, out ERROR CLASS: CST(ERROR CLASS: Unexpected classifier: null, @FlexibleNullability kotlin/String..ERROR CLASS: CST(ERROR CLASS: Unexpected classifier: null, @FlexibleNullability kotlin/String?!>? & EnumerableAssert<*, out kotlin.Comparable<kotlin.String & kotlin.Char> & java.io.Serializable..kotlin.Comparable<kotlin.String & kotlin.Char>? & java.io.Serializable?>?")!>assertion<!>
 }

compiler/testData/ir/irText/classes/delegatedImplementationOfJavaInterface.fir.txt

@@ -30,16 +30,16 @@ FILE fqName:<root> fileName:/delegatedImplementationOfJavaInterface.kt
           $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_0> type:<root>.J visibility:local [final]' type=<root>.J origin=null
             receiver: GET_VAR '<this>: <root>.Test declared in <root>.Test.takeNotNull' type=<root>.Test origin=null
           x: GET_VAR 'x: @[EnhancedNullability] kotlin.String declared in <root>.Test.takeNotNull' type=@[EnhancedNullability] kotlin.String origin=null
-    FUN DELEGATED_MEMBER name:takeNullable visibility:public modality:OPEN <> ($this:<root>.Test, x:kotlin.String?) returnType:kotlin.Unit
+    FUN DELEGATED_MEMBER name:takeNullable visibility:public modality:OPEN <> ($this:<root>.Test, x:@[FlexibleNullability] kotlin.String?) returnType:kotlin.Unit
       overridden:
-        public abstract fun takeNullable (x: kotlin.String?): kotlin.Unit declared in <root>.J
+        public abstract fun takeNullable (x: @[FlexibleNullability] kotlin.String?): kotlin.Unit declared in <root>.J
       $this: VALUE_PARAMETER name:<this> type:<root>.Test
-      VALUE_PARAMETER name:x index:0 type:kotlin.String?
+      VALUE_PARAMETER name:x index:0 type:@[FlexibleNullability] kotlin.String?
       BLOCK_BODY
-        CALL 'public abstract fun takeNullable (x: kotlin.String?): kotlin.Unit declared in <root>.J' type=kotlin.Unit origin=null
+        CALL 'public abstract fun takeNullable (x: @[FlexibleNullability] kotlin.String?): kotlin.Unit declared in <root>.J' type=kotlin.Unit origin=null
           $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_0> type:<root>.J visibility:local [final]' type=<root>.J origin=null
             receiver: GET_VAR '<this>: <root>.Test declared in <root>.Test.takeNullable' type=<root>.Test origin=null
-          x: GET_VAR 'x: kotlin.String? declared in <root>.Test.takeNullable' type=kotlin.String? origin=null
+          x: GET_VAR 'x: @[FlexibleNullability] kotlin.String? declared in <root>.Test.takeNullable' type=@[FlexibleNullability] kotlin.String? origin=null
     FUN DELEGATED_MEMBER name:takeFlexible visibility:public modality:OPEN <> ($this:<root>.Test, x:kotlin.String?) returnType:kotlin.Unit
       overridden:
         public abstract fun takeFlexible (x: kotlin.String?): kotlin.Unit declared in <root>.J
@@ -59,13 +59,13 @@ FILE fqName:<root> fileName:/delegatedImplementationOfJavaInterface.kt
           CALL 'public abstract fun returnNotNull (): @[EnhancedNullability] kotlin.String declared in <root>.J' type=@[EnhancedNullability] kotlin.String origin=null
             $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_0> type:<root>.J visibility:local [final]' type=<root>.J origin=null
               receiver: GET_VAR '<this>: <root>.Test declared in <root>.Test.returnNotNull' type=<root>.Test origin=null
-    FUN DELEGATED_MEMBER name:returnNullable visibility:public modality:OPEN <> ($this:<root>.Test) returnType:kotlin.String?
+    FUN DELEGATED_MEMBER name:returnNullable visibility:public modality:OPEN <> ($this:<root>.Test) returnType:@[FlexibleNullability] kotlin.String?
       overridden:
-        public abstract fun returnNullable (): kotlin.String? declared in <root>.J
+        public abstract fun returnNullable (): @[FlexibleNullability] kotlin.String? declared in <root>.J
       $this: VALUE_PARAMETER name:<this> type:<root>.Test
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public open fun returnNullable (): kotlin.String? declared in <root>.Test'
+        RETURN type=kotlin.Nothing from='public open fun returnNullable (): @[FlexibleNullability] kotlin.String? declared in <root>.Test'
-          CALL 'public abstract fun returnNullable (): kotlin.String? declared in <root>.J' type=kotlin.String? origin=null
+          CALL 'public abstract fun returnNullable (): @[FlexibleNullability] kotlin.String? declared in <root>.J' type=@[FlexibleNullability] kotlin.String? origin=null
             $this: GET_FIELD 'FIELD DELEGATE name:<$$delegate_0> type:<root>.J visibility:local [final]' type=<root>.J origin=null
               receiver: GET_VAR '<this>: <root>.Test declared in <root>.Test.returnNullable' type=<root>.Test origin=null
     FUN DELEGATED_MEMBER name:returnsFlexible visibility:public modality:OPEN <> ($this:<root>.Test) returnType:kotlin.String?

compiler/testData/ir/irText/classes/implicitNotNullOnDelegatedImplementation.fir.txt

@@ -22,9 +22,9 @@ FILE fqName:<root> fileName:/implicitNotNullOnDelegatedImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JFoo'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:K1 modality:FINAL visibility:public superTypes:[<root>.JFoo]'
-    FUN FAKE_OVERRIDE name:foo visibility:public modality:OPEN <> ($this:<root>.JFoo) returnType:kotlin.String [fake_override]
+    FUN FAKE_OVERRIDE name:foo visibility:public modality:OPEN <> ($this:<root>.JFoo) returnType:@[FlexibleNullability] kotlin.String [fake_override]
       overridden:
-        public open fun foo (): kotlin.String declared in <root>.JFoo
+        public open fun foo (): @[FlexibleNullability] kotlin.String declared in <root>.JFoo
       $this: VALUE_PARAMETER name:<this> type:<root>.JFoo
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
@@ -45,13 +45,13 @@ FILE fqName:<root> fileName:/implicitNotNullOnDelegatedImplementation.kt
       BLOCK_BODY
         DELEGATING_CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.JFoo'
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:K2 modality:FINAL visibility:public superTypes:[<root>.JFoo]'
-    FUN name:foo visibility:public modality:FINAL <> ($this:<root>.K2) returnType:kotlin.String
+    FUN name:foo visibility:public modality:FINAL <> ($this:<root>.K2) returnType:@[FlexibleNullability] kotlin.String
       overridden:
-        public open fun foo (): kotlin.String declared in <root>.JFoo
+        public open fun foo (): @[FlexibleNullability] kotlin.String declared in <root>.JFoo
       $this: VALUE_PARAMETER name:<this> type:<root>.K2
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public final fun foo (): kotlin.String declared in <root>.K2'
+        RETURN type=kotlin.Nothing from='public final fun foo (): @[FlexibleNullability] kotlin.String declared in <root>.K2'
-          CALL 'public open fun foo (): kotlin.String declared in <root>.JFoo' superQualifier='CLASS IR_EXTERNAL_JAVA_DECLARATION_STUB CLASS name:JFoo modality:OPEN visibility:public superTypes:[kotlin.Any; <root>.IFoo]' type=kotlin.String origin=null
+          CALL 'public open fun foo (): @[FlexibleNullability] kotlin.String declared in <root>.JFoo' superQualifier='CLASS IR_EXTERNAL_JAVA_DECLARATION_STUB CLASS name:JFoo modality:OPEN visibility:public superTypes:[kotlin.Any; <root>.IFoo]' type=@[FlexibleNullability] kotlin.String origin=null
             $this: GET_VAR '<this>: <root>.K2 declared in <root>.K2.foo' type=<root>.K2 origin=null
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:

compiler/testData/ir/irText/classes/kt43217.fir.txt

@@ -17,7 +17,7 @@ FILE fqName:<root> fileName:/kt43217.kt
                   INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:<no name provided> modality:FINAL visibility:local superTypes:[<root>.DoubleExpression]'
               FUN name:get visibility:public modality:FINAL <> ($this:<root>.A.b.<no name provided>) returnType:kotlin.Double [operator]
                 overridden:
-                  public abstract fun get (): T of <root>.ObservableValue [operator] declared in <root>.ObservableValue
+                  public abstract fun get (): @[FlexibleNullability] T of <root>.ObservableValue [operator] declared in <root>.ObservableValue
                 $this: VALUE_PARAMETER name:<this> type:<root>.A.b.<no name provided>
                 BLOCK_BODY
                   RETURN type=kotlin.Nothing from='public final fun get (): kotlin.Double [operator] declared in <root>.A.b.<no name provided>'
@@ -69,7 +69,7 @@ FILE fqName:<root> fileName:/kt43217.kt
         INSTANCE_INITIALIZER_CALL classDescriptor='CLASS CLASS name:C modality:FINAL visibility:public superTypes:[<root>.DoubleExpression]'
     FUN name:get visibility:public modality:FINAL <> ($this:<root>.C) returnType:kotlin.Double [operator]
       overridden:
-        public abstract fun get (): T of <root>.ObservableValue [operator] declared in <root>.ObservableValue
+        public abstract fun get (): @[FlexibleNullability] T of <root>.ObservableValue [operator] declared in <root>.ObservableValue
       $this: VALUE_PARAMETER name:<this> type:<root>.C
       BLOCK_BODY
         RETURN type=kotlin.Nothing from='public final fun get (): kotlin.Double [operator] declared in <root>.C'

compiler/testData/ir/irText/firProblems/AbstractMutableMap.fir.txt

@@ -104,7 +104,7 @@ FILE fqName:<root> fileName:/AbstractMutableMap.kt
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
-        public open fun equals (p0: kotlin.Any?): kotlin.Boolean [operator] declared in java.util.AbstractMap
+        public open fun equals (p0: @[FlexibleNullability] kotlin.Any?): kotlin.Boolean [operator] declared in java.util.AbstractMap
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any
       VALUE_PARAMETER name:other index:0 type:kotlin.Any?
     FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
@@ -115,7 +115,7 @@ FILE fqName:<root> fileName:/AbstractMutableMap.kt
     FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
       overridden:
         public open fun toString (): kotlin.String declared in kotlin.Any
-        public open fun toString (): kotlin.String declared in java.util.AbstractMap
+        public open fun toString (): @[FlexibleNullability] kotlin.String declared in java.util.AbstractMap
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any
     FUN FAKE_OVERRIDE name:keySet visibility:public modality:OPEN <> ($this:java.util.AbstractMap<K of java.util.AbstractMap, V of java.util.AbstractMap>) returnType:kotlin.collections.Set<K of <root>.MyMap?>? [fake_override]
       overridden:

compiler/testData/ir/irText/firProblems/ClashResolutionDescriptor.fir.txt

@@ -152,7 +152,7 @@ FILE fqName:<root> fileName:/ClashResolutionDescriptor.kt
               BLOCK type=kotlin.collections.Collection<<root>.ComponentDescriptor> origin=ELVIS
                 VAR IR_TEMPORARY_VARIABLE name:tmp_1 type:kotlin.collections.Collection<<root>.ComponentDescriptor>? [val]
                   TYPE_OP type=kotlin.collections.Collection<<root>.ComponentDescriptor>? origin=SAFE_CAST typeOperand=kotlin.collections.Collection<<root>.ComponentDescriptor>
-                    CALL 'public open fun get (p0: K of java.util.HashMap?): V of java.util.HashMap? [operator] declared in java.util.HashMap' type=kotlin.Any? origin=null
+                    CALL 'public open fun get (p0: K of java.util.HashMap?): @[FlexibleNullability] V of java.util.HashMap? [operator] declared in java.util.HashMap' type=kotlin.Any? origin=null
                       $this: CALL 'private final fun <get-registrationMap> (): java.util.HashMap<java.lang.reflect.Type, kotlin.Any> declared in <root>' type=java.util.HashMap<java.lang.reflect.Type, kotlin.Any> origin=GET_PROPERTY
                       p0: CALL 'public final fun <get-applicableTo> (): java.lang.Class<E of <root>.PlatformExtensionsClashResolver> declared in <root>.PlatformExtensionsClashResolver' type=java.lang.Class<out <root>.PlatformSpecificExtension<out <root>.PlatformSpecificExtension<out <root>.PlatformSpecificExtension<out <root>.PlatformSpecificExtension<out <root>.PlatformSpecificExtension<out kotlin.Any?>>>>>> origin=GET_PROPERTY
                         $this: GET_VAR 'val resolver: <root>.PlatformExtensionsClashResolver<*> [val] declared in <root>.resolveClashesIfAny' type=<root>.PlatformExtensionsClashResolver<*> origin=null

compiler/testData/ir/irText/firProblems/MultiList.fir.txt

@@ -206,10 +206,10 @@ FILE fqName:<root> fileName:/MultiList.kt
         public abstract fun isEmpty (): kotlin.Boolean declared in kotlin.collections.List
         public open fun isEmpty (): kotlin.Boolean declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:kotlin.collections.List<E of kotlin.collections.List>
-    FUN FAKE_OVERRIDE name:iterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:kotlin.collections.MutableIterator<<root>.Some<T of <root>.SomeList>?> [fake_override,operator]
+    FUN FAKE_OVERRIDE name:iterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:@[FlexibleNullability] kotlin.collections.MutableIterator<<root>.Some<T of <root>.SomeList>?> [fake_override,operator]
       overridden:
         public abstract fun iterator (): kotlin.collections.Iterator<<root>.Some<T of <root>.MyList>> [fake_override,operator] declared in <root>.MyList
-        public open fun iterator (): kotlin.collections.MutableIterator<E of java.util.ArrayList?> [operator] declared in java.util.ArrayList
+        public open fun iterator (): @[FlexibleNullability] kotlin.collections.MutableIterator<E of java.util.ArrayList?> [operator] declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
     FUN FAKE_OVERRIDE name:lastIndexOf visibility:public modality:OPEN <> ($this:kotlin.collections.List<E of kotlin.collections.List>, element:<root>.Some<T of <root>.SomeList>) returnType:kotlin.Int [fake_override]
       overridden:
@@ -217,21 +217,21 @@ FILE fqName:<root> fileName:/MultiList.kt
         public open fun lastIndexOf (p0: E of java.util.ArrayList?): kotlin.Int declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:kotlin.collections.List<E of kotlin.collections.List>
       VALUE_PARAMETER name:element index:0 type:<root>.Some<T of <root>.SomeList>
-    FUN FAKE_OVERRIDE name:listIterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:kotlin.collections.MutableListIterator<<root>.Some<T of <root>.SomeList>?> [fake_override]
+    FUN FAKE_OVERRIDE name:listIterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:@[FlexibleNullability] kotlin.collections.MutableListIterator<<root>.Some<T of <root>.SomeList>?> [fake_override]
       overridden:
         public abstract fun listIterator (): kotlin.collections.ListIterator<<root>.Some<T of <root>.MyList>> [fake_override] declared in <root>.MyList
-        public open fun listIterator (): kotlin.collections.MutableListIterator<E of java.util.ArrayList?> declared in java.util.ArrayList
+        public open fun listIterator (): @[FlexibleNullability] kotlin.collections.MutableListIterator<E of java.util.ArrayList?> declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
-    FUN FAKE_OVERRIDE name:listIterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int) returnType:kotlin.collections.MutableListIterator<<root>.Some<T of <root>.SomeList>?> [fake_override]
+    FUN FAKE_OVERRIDE name:listIterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int) returnType:@[FlexibleNullability] kotlin.collections.MutableListIterator<<root>.Some<T of <root>.SomeList>?> [fake_override]
       overridden:
         public abstract fun listIterator (index: kotlin.Int): kotlin.collections.ListIterator<<root>.Some<T of <root>.MyList>> [fake_override] declared in <root>.MyList
-        public open fun listIterator (p0: kotlin.Int): kotlin.collections.MutableListIterator<E of java.util.ArrayList?> declared in java.util.ArrayList
+        public open fun listIterator (p0: kotlin.Int): @[FlexibleNullability] kotlin.collections.MutableListIterator<E of java.util.ArrayList?> declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
       VALUE_PARAMETER name:p0 index:0 type:kotlin.Int
-    FUN FAKE_OVERRIDE name:subList visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int, p1:kotlin.Int) returnType:kotlin.collections.MutableList<<root>.Some<T of <root>.SomeList>?> [fake_override]
+    FUN FAKE_OVERRIDE name:subList visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int, p1:kotlin.Int) returnType:@[FlexibleNullability] kotlin.collections.MutableList<<root>.Some<T of <root>.SomeList>?> [fake_override]
       overridden:
         public abstract fun subList (fromIndex: kotlin.Int, toIndex: kotlin.Int): kotlin.collections.List<<root>.Some<T of <root>.MyList>> [fake_override] declared in <root>.MyList
-        public open fun subList (p0: kotlin.Int, p1: kotlin.Int): kotlin.collections.MutableList<E of java.util.ArrayList?> declared in java.util.ArrayList
+        public open fun subList (p0: kotlin.Int, p1: kotlin.Int): @[FlexibleNullability] kotlin.collections.MutableList<E of java.util.ArrayList?> declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
       VALUE_PARAMETER name:p0 index:0 type:kotlin.Int
       VALUE_PARAMETER name:p1 index:1 type:kotlin.Int
@@ -249,7 +249,7 @@ FILE fqName:<root> fileName:/MultiList.kt
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
-        public open fun equals (p0: kotlin.Any?): kotlin.Boolean [operator] declared in java.util.ArrayList
+        public open fun equals (p0: @[FlexibleNullability] kotlin.Any?): kotlin.Boolean [operator] declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any
       VALUE_PARAMETER name:other index:0 type:kotlin.Any?
     FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
@@ -260,7 +260,7 @@ FILE fqName:<root> fileName:/MultiList.kt
     FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
       overridden:
         public open fun toString (): kotlin.String declared in kotlin.Any
-        public open fun toString (): kotlin.String declared in java.util.ArrayList
+        public open fun toString (): @[FlexibleNullability] kotlin.String declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any
     FUN FAKE_OVERRIDE name:elementData visibility:public/*package*/ modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int) returnType:<root>.Some<T of <root>.SomeList>? [fake_override]
       overridden:
@@ -276,9 +276,9 @@ FILE fqName:<root> fileName:/MultiList.kt
         public open fun ensureCapacity (p0: kotlin.Int): kotlin.Unit declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
       VALUE_PARAMETER name:p0 index:0 type:kotlin.Int
-    FUN FAKE_OVERRIDE name:clone visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:kotlin.Any [fake_override]
+    FUN FAKE_OVERRIDE name:clone visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:@[FlexibleNullability] kotlin.Any [fake_override]
       overridden:
-        public open fun clone (): kotlin.Any declared in java.util.ArrayList
+        public open fun clone (): @[FlexibleNullability] kotlin.Any declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
     FUN FAKE_OVERRIDE name:toArray visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:kotlin.Array<out kotlin.Any?>? [fake_override]
       overridden:
@@ -321,17 +321,17 @@ FILE fqName:<root> fileName:/MultiList.kt
       overridden:
         public open fun clear (): kotlin.Unit declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
-    FUN FAKE_OVERRIDE name:addAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.collections.Collection<out <root>.Some<T of <root>.SomeList>?>) returnType:kotlin.Boolean [fake_override]
+    FUN FAKE_OVERRIDE name:addAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:@[FlexibleNullability] kotlin.collections.Collection<out <root>.Some<T of <root>.SomeList>?>) returnType:kotlin.Boolean [fake_override]
       overridden:
-        public open fun addAll (p0: kotlin.collections.Collection<out E of java.util.ArrayList?>): kotlin.Boolean declared in java.util.ArrayList
+        public open fun addAll (p0: @[FlexibleNullability] kotlin.collections.Collection<out E of java.util.ArrayList?>): kotlin.Boolean declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
-      VALUE_PARAMETER name:p0 index:0 type:kotlin.collections.Collection<out <root>.Some<T of <root>.SomeList>?>
+      VALUE_PARAMETER name:p0 index:0 type:@[FlexibleNullability] kotlin.collections.Collection<out <root>.Some<T of <root>.SomeList>?>
-    FUN FAKE_OVERRIDE name:addAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int, p1:kotlin.collections.Collection<out <root>.Some<T of <root>.SomeList>?>) returnType:kotlin.Boolean [fake_override]
+    FUN FAKE_OVERRIDE name:addAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int, p1:@[FlexibleNullability] kotlin.collections.Collection<out <root>.Some<T of <root>.SomeList>?>) returnType:kotlin.Boolean [fake_override]
       overridden:
-        public open fun addAll (p0: kotlin.Int, p1: kotlin.collections.Collection<out E of java.util.ArrayList?>): kotlin.Boolean declared in java.util.ArrayList
+        public open fun addAll (p0: kotlin.Int, p1: @[FlexibleNullability] kotlin.collections.Collection<out E of java.util.ArrayList?>): kotlin.Boolean declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
       VALUE_PARAMETER name:p0 index:0 type:kotlin.Int
-      VALUE_PARAMETER name:p1 index:1 type:kotlin.collections.Collection<out <root>.Some<T of <root>.SomeList>?>
+      VALUE_PARAMETER name:p1 index:1 type:@[FlexibleNullability] kotlin.collections.Collection<out <root>.Some<T of <root>.SomeList>?>
     FUN FAKE_OVERRIDE name:removeRange visibility:protected/*protected and package*/ modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int, p1:kotlin.Int) returnType:kotlin.Unit [fake_override]
       overridden:
         protected/*protected and package*/ open fun removeRange (p0: kotlin.Int, p1: kotlin.Int): kotlin.Unit declared in java.util.ArrayList
@@ -354,21 +354,21 @@ FILE fqName:<root> fileName:/MultiList.kt
         public open fun forEach (p0: java.util.function.Consumer<in E of java.util.ArrayList?>?): kotlin.Unit declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.lang.Iterable<T of java.lang.Iterable>
       VALUE_PARAMETER name:p0 index:0 type:java.util.function.Consumer<in <root>.Some<T of <root>.SomeList>?>?
-    FUN FAKE_OVERRIDE name:spliterator visibility:public modality:OPEN <> ($this:java.util.Collection<E of java.util.Collection>) returnType:java.util.Spliterator<<root>.Some<T of <root>.SomeList>?> [fake_override]
+    FUN FAKE_OVERRIDE name:spliterator visibility:public modality:OPEN <> ($this:java.util.Collection<E of java.util.Collection>) returnType:@[FlexibleNullability] java.util.Spliterator<<root>.Some<T of <root>.SomeList>?> [fake_override]
       overridden:
-        public open fun spliterator (): java.util.Spliterator<<root>.Some<T of <root>.MyList>?> declared in <root>.MyList
+        public open fun spliterator (): @[FlexibleNullability] java.util.Spliterator<<root>.Some<T of <root>.MyList>?> declared in <root>.MyList
-        public open fun spliterator (): java.util.Spliterator<E of java.util.ArrayList?> declared in java.util.ArrayList
+        public open fun spliterator (): @[FlexibleNullability] java.util.Spliterator<E of java.util.ArrayList?> declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.Collection<E of java.util.Collection>
     FUN FAKE_OVERRIDE name:removeIf visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:java.util.function.Predicate<in <root>.Some<T of <root>.SomeList>?>?) returnType:kotlin.Boolean [fake_override]
       overridden:
         public open fun removeIf (p0: java.util.function.Predicate<in E of java.util.ArrayList?>?): kotlin.Boolean declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
       VALUE_PARAMETER name:p0 index:0 type:java.util.function.Predicate<in <root>.Some<T of <root>.SomeList>?>?
-    FUN FAKE_OVERRIDE name:replaceAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:java.util.function.UnaryOperator<<root>.Some<T of <root>.SomeList>?>) returnType:kotlin.Unit [fake_override]
+    FUN FAKE_OVERRIDE name:replaceAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:@[FlexibleNullability] java.util.function.UnaryOperator<<root>.Some<T of <root>.SomeList>?>) returnType:kotlin.Unit [fake_override]
       overridden:
-        public open fun replaceAll (p0: java.util.function.UnaryOperator<E of java.util.ArrayList?>): kotlin.Unit declared in java.util.ArrayList
+        public open fun replaceAll (p0: @[FlexibleNullability] java.util.function.UnaryOperator<E of java.util.ArrayList?>): kotlin.Unit declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
-      VALUE_PARAMETER name:p0 index:0 type:java.util.function.UnaryOperator<<root>.Some<T of <root>.SomeList>?>
+      VALUE_PARAMETER name:p0 index:0 type:@[FlexibleNullability] java.util.function.UnaryOperator<<root>.Some<T of <root>.SomeList>?>
     FUN FAKE_OVERRIDE name:sort visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:java.util.Comparator<in <root>.Some<T of <root>.SomeList>?>?) returnType:kotlin.Unit [fake_override]
       overridden:
         public open fun sort (p0: java.util.Comparator<in E of java.util.ArrayList?>?): kotlin.Unit declared in java.util.ArrayList
@@ -411,27 +411,27 @@ FILE fqName:<root> fileName:/MultiList.kt
         public abstract fun isEmpty (): kotlin.Boolean declared in kotlin.collections.List
         public open fun isEmpty (): kotlin.Boolean declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:kotlin.collections.List<E of kotlin.collections.List>
-    FUN FAKE_OVERRIDE name:iterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:kotlin.collections.MutableIterator<<root>.Some<kotlin.String>?> [fake_override,operator]
+    FUN FAKE_OVERRIDE name:iterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:@[FlexibleNullability] kotlin.collections.MutableIterator<<root>.Some<kotlin.String>?> [fake_override,operator]
       overridden:
-        public open fun iterator (): kotlin.collections.MutableIterator<E of java.util.ArrayList?> [operator] declared in java.util.ArrayList
+        public open fun iterator (): @[FlexibleNullability] kotlin.collections.MutableIterator<E of java.util.ArrayList?> [operator] declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
     FUN FAKE_OVERRIDE name:lastIndexOf visibility:public modality:OPEN <> ($this:kotlin.collections.List<E of kotlin.collections.List>, element:<root>.Some<kotlin.String>) returnType:kotlin.Int [fake_override]
       overridden:
         public abstract fun lastIndexOf (element: E of kotlin.collections.List): kotlin.Int declared in kotlin.collections.List
       $this: VALUE_PARAMETER name:<this> type:kotlin.collections.List<E of kotlin.collections.List>
       VALUE_PARAMETER name:element index:0 type:<root>.Some<kotlin.String>
-    FUN FAKE_OVERRIDE name:listIterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:kotlin.collections.MutableListIterator<<root>.Some<kotlin.String>?> [fake_override]
+    FUN FAKE_OVERRIDE name:listIterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:@[FlexibleNullability] kotlin.collections.MutableListIterator<<root>.Some<kotlin.String>?> [fake_override]
       overridden:
-        public open fun listIterator (): kotlin.collections.MutableListIterator<E of java.util.ArrayList?> declared in java.util.ArrayList
+        public open fun listIterator (): @[FlexibleNullability] kotlin.collections.MutableListIterator<E of java.util.ArrayList?> declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
-    FUN FAKE_OVERRIDE name:listIterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int) returnType:kotlin.collections.MutableListIterator<<root>.Some<kotlin.String>?> [fake_override]
+    FUN FAKE_OVERRIDE name:listIterator visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int) returnType:@[FlexibleNullability] kotlin.collections.MutableListIterator<<root>.Some<kotlin.String>?> [fake_override]
       overridden:
-        public open fun listIterator (p0: kotlin.Int): kotlin.collections.MutableListIterator<E of java.util.ArrayList?> declared in java.util.ArrayList
+        public open fun listIterator (p0: kotlin.Int): @[FlexibleNullability] kotlin.collections.MutableListIterator<E of java.util.ArrayList?> declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
       VALUE_PARAMETER name:p0 index:0 type:kotlin.Int
-    FUN FAKE_OVERRIDE name:subList visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int, p1:kotlin.Int) returnType:kotlin.collections.MutableList<<root>.Some<kotlin.String>?> [fake_override]
+    FUN FAKE_OVERRIDE name:subList visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int, p1:kotlin.Int) returnType:@[FlexibleNullability] kotlin.collections.MutableList<<root>.Some<kotlin.String>?> [fake_override]
       overridden:
-        public open fun subList (p0: kotlin.Int, p1: kotlin.Int): kotlin.collections.MutableList<E of java.util.ArrayList?> declared in java.util.ArrayList
+        public open fun subList (p0: kotlin.Int, p1: kotlin.Int): @[FlexibleNullability] kotlin.collections.MutableList<E of java.util.ArrayList?> declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
       VALUE_PARAMETER name:p0 index:0 type:kotlin.Int
       VALUE_PARAMETER name:p1 index:1 type:kotlin.Int
@@ -449,7 +449,7 @@ FILE fqName:<root> fileName:/MultiList.kt
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any
-        public open fun equals (p0: kotlin.Any?): kotlin.Boolean [operator] declared in java.util.ArrayList
+        public open fun equals (p0: @[FlexibleNullability] kotlin.Any?): kotlin.Boolean [operator] declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any
       VALUE_PARAMETER name:other index:0 type:kotlin.Any?
     FUN FAKE_OVERRIDE name:hashCode visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.Int [fake_override]
@@ -460,7 +460,7 @@ FILE fqName:<root> fileName:/MultiList.kt
     FUN FAKE_OVERRIDE name:toString visibility:public modality:OPEN <> ($this:kotlin.Any) returnType:kotlin.String [fake_override]
       overridden:
         public open fun toString (): kotlin.String declared in kotlin.Any
-        public open fun toString (): kotlin.String declared in java.util.ArrayList
+        public open fun toString (): @[FlexibleNullability] kotlin.String declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:kotlin.Any
     FUN FAKE_OVERRIDE name:elementData visibility:public/*package*/ modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int) returnType:<root>.Some<kotlin.String>? [fake_override]
       overridden:
@@ -476,9 +476,9 @@ FILE fqName:<root> fileName:/MultiList.kt
         public open fun ensureCapacity (p0: kotlin.Int): kotlin.Unit declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
       VALUE_PARAMETER name:p0 index:0 type:kotlin.Int
-    FUN FAKE_OVERRIDE name:clone visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:kotlin.Any [fake_override]
+    FUN FAKE_OVERRIDE name:clone visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:@[FlexibleNullability] kotlin.Any [fake_override]
       overridden:
-        public open fun clone (): kotlin.Any declared in java.util.ArrayList
+        public open fun clone (): @[FlexibleNullability] kotlin.Any declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
     FUN FAKE_OVERRIDE name:toArray visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>) returnType:kotlin.Array<out kotlin.Any?>? [fake_override]
       overridden:
@@ -521,17 +521,17 @@ FILE fqName:<root> fileName:/MultiList.kt
       overridden:
         public open fun clear (): kotlin.Unit declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
-    FUN FAKE_OVERRIDE name:addAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.collections.Collection<out <root>.Some<kotlin.String>?>) returnType:kotlin.Boolean [fake_override]
+    FUN FAKE_OVERRIDE name:addAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:@[FlexibleNullability] kotlin.collections.Collection<out <root>.Some<kotlin.String>?>) returnType:kotlin.Boolean [fake_override]
       overridden:
-        public open fun addAll (p0: kotlin.collections.Collection<out E of java.util.ArrayList?>): kotlin.Boolean declared in java.util.ArrayList
+        public open fun addAll (p0: @[FlexibleNullability] kotlin.collections.Collection<out E of java.util.ArrayList?>): kotlin.Boolean declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
-      VALUE_PARAMETER name:p0 index:0 type:kotlin.collections.Collection<out <root>.Some<kotlin.String>?>
+      VALUE_PARAMETER name:p0 index:0 type:@[FlexibleNullability] kotlin.collections.Collection<out <root>.Some<kotlin.String>?>
-    FUN FAKE_OVERRIDE name:addAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int, p1:kotlin.collections.Collection<out <root>.Some<kotlin.String>?>) returnType:kotlin.Boolean [fake_override]
+    FUN FAKE_OVERRIDE name:addAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int, p1:@[FlexibleNullability] kotlin.collections.Collection<out <root>.Some<kotlin.String>?>) returnType:kotlin.Boolean [fake_override]
       overridden:
-        public open fun addAll (p0: kotlin.Int, p1: kotlin.collections.Collection<out E of java.util.ArrayList?>): kotlin.Boolean declared in java.util.ArrayList
+        public open fun addAll (p0: kotlin.Int, p1: @[FlexibleNullability] kotlin.collections.Collection<out E of java.util.ArrayList?>): kotlin.Boolean declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
       VALUE_PARAMETER name:p0 index:0 type:kotlin.Int
-      VALUE_PARAMETER name:p1 index:1 type:kotlin.collections.Collection<out <root>.Some<kotlin.String>?>
+      VALUE_PARAMETER name:p1 index:1 type:@[FlexibleNullability] kotlin.collections.Collection<out <root>.Some<kotlin.String>?>
     FUN FAKE_OVERRIDE name:removeRange visibility:protected/*protected and package*/ modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:kotlin.Int, p1:kotlin.Int) returnType:kotlin.Unit [fake_override]
       overridden:
         protected/*protected and package*/ open fun removeRange (p0: kotlin.Int, p1: kotlin.Int): kotlin.Unit declared in java.util.ArrayList
@@ -553,20 +553,20 @@ FILE fqName:<root> fileName:/MultiList.kt
         public open fun forEach (p0: java.util.function.Consumer<in T of java.lang.Iterable?>?): kotlin.Unit declared in java.lang.Iterable
       $this: VALUE_PARAMETER name:<this> type:java.lang.Iterable<T of java.lang.Iterable>
       VALUE_PARAMETER name:p0 index:0 type:java.util.function.Consumer<in <root>.Some<kotlin.String>?>?
-    FUN FAKE_OVERRIDE name:spliterator visibility:public modality:OPEN <> ($this:java.util.Collection<E of java.util.Collection>) returnType:java.util.Spliterator<<root>.Some<kotlin.String>?> [fake_override]
+    FUN FAKE_OVERRIDE name:spliterator visibility:public modality:OPEN <> ($this:java.util.Collection<E of java.util.Collection>) returnType:@[FlexibleNullability] java.util.Spliterator<<root>.Some<kotlin.String>?> [fake_override]
       overridden:
-        public open fun spliterator (): java.util.Spliterator<E of java.util.Collection?> declared in java.util.Collection
+        public open fun spliterator (): @[FlexibleNullability] java.util.Spliterator<E of java.util.Collection?> declared in java.util.Collection
       $this: VALUE_PARAMETER name:<this> type:java.util.Collection<E of java.util.Collection>
     FUN FAKE_OVERRIDE name:removeIf visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:java.util.function.Predicate<in <root>.Some<kotlin.String>?>?) returnType:kotlin.Boolean [fake_override]
       overridden:
         public open fun removeIf (p0: java.util.function.Predicate<in E of java.util.ArrayList?>?): kotlin.Boolean declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
       VALUE_PARAMETER name:p0 index:0 type:java.util.function.Predicate<in <root>.Some<kotlin.String>?>?
-    FUN FAKE_OVERRIDE name:replaceAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:java.util.function.UnaryOperator<<root>.Some<kotlin.String>?>) returnType:kotlin.Unit [fake_override]
+    FUN FAKE_OVERRIDE name:replaceAll visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:@[FlexibleNullability] java.util.function.UnaryOperator<<root>.Some<kotlin.String>?>) returnType:kotlin.Unit [fake_override]
       overridden:
-        public open fun replaceAll (p0: java.util.function.UnaryOperator<E of java.util.ArrayList?>): kotlin.Unit declared in java.util.ArrayList
+        public open fun replaceAll (p0: @[FlexibleNullability] java.util.function.UnaryOperator<E of java.util.ArrayList?>): kotlin.Unit declared in java.util.ArrayList
       $this: VALUE_PARAMETER name:<this> type:java.util.ArrayList<E of java.util.ArrayList>
-      VALUE_PARAMETER name:p0 index:0 type:java.util.function.UnaryOperator<<root>.Some<kotlin.String>?>
+      VALUE_PARAMETER name:p0 index:0 type:@[FlexibleNullability] java.util.function.UnaryOperator<<root>.Some<kotlin.String>?>
     FUN FAKE_OVERRIDE name:sort visibility:public modality:OPEN <> ($this:java.util.ArrayList<E of java.util.ArrayList>, p0:java.util.Comparator<in <root>.Some<kotlin.String>?>?) returnType:kotlin.Unit [fake_override]
       overridden:
         public open fun sort (p0: java.util.Comparator<in E of java.util.ArrayList?>?): kotlin.Unit declared in java.util.ArrayList

compiler/testData/ir/irText/firProblems/coercionToUnitForNestedWhen.fir.txt

@@ -61,7 +61,7 @@ FILE fqName:<root> fileName:/coercionToUnitForNestedWhen.kt
             then: CONST Boolean type=kotlin.Boolean value=false
         body: BLOCK type=kotlin.Unit origin=null
           TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
-            WHEN type=java.lang.StringBuilder? origin=IF
+            WHEN type=@[FlexibleNullability] java.lang.StringBuilder? origin=IF
               BRANCH
                 if: CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
                   arg0: TYPE_OP type=kotlin.Char origin=IMPLICIT_CAST typeOperand=kotlin.Char

compiler/testData/ir/irText/regressions/typeParametersInImplicitCast.fir.txt

@@ -14,6 +14,6 @@ FILE fqName:<root> fileName:/typeParametersInImplicitCast.kt
               BLOCK_BODY
                 RETURN type=kotlin.Nothing from='local final fun <anonymous> (it: kotlin.collections.List<T of <root>.problematic>): kotlin.collections.Iterable<T of <root>.problematic> declared in <root>.problematic'
                   TYPE_OP type=kotlin.collections.List<T of <root>.problematic?> origin=IMPLICIT_NOTNULL typeOperand=kotlin.collections.List<T of <root>.problematic?>
-                    CALL 'public/*package*/ open fun id <T> (v: kotlin.collections.List<T of <root>.ListId.id?>?): kotlin.collections.List<T of <root>.ListId.id?> declared in <root>.ListId' type=kotlin.collections.List<T of <root>.problematic?> origin=null
+                    CALL 'public/*package*/ open fun id <T> (v: kotlin.collections.List<T of <root>.ListId.id?>?): @[EnhancedNullability] kotlin.collections.List<T of <root>.ListId.id?> declared in <root>.ListId' type=@[EnhancedNullability] kotlin.collections.List<T of <root>.problematic?> origin=null
                       <T>: T of <root>.problematic?
                       v: GET_VAR 'it: kotlin.collections.List<T of <root>.problematic> declared in <root>.problematic.<anonymous>' type=kotlin.collections.List<T of <root>.problematic> origin=null

compiler/testData/ir/irText/stubs/builtinMap.fir.txt

@@ -28,7 +28,7 @@ FILE fqName:<root> fileName:/builtinMap.kt
                   BLOCK_BODY
                     RETURN type=kotlin.Nothing from='local final fun <anonymous> (): kotlin.Unit declared in <root>.plus'
                       TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
-                        CALL 'public open fun put (p0: K of java.util.LinkedHashMap?, p1: V of java.util.LinkedHashMap?): V of java.util.LinkedHashMap? declared in java.util.LinkedHashMap' type=V1 of <root>.plus? origin=null
+                        CALL 'public open fun put (p0: @[FlexibleNullability] K of java.util.LinkedHashMap?, p1: @[FlexibleNullability] V of java.util.LinkedHashMap?): @[FlexibleNullability] V of java.util.LinkedHashMap? declared in java.util.LinkedHashMap' type=V1 of <root>.plus? origin=null
                           $this: GET_VAR '<this>: java.util.LinkedHashMap<K1 of <root>.plus?, V1 of <root>.plus?> declared in <root>.plus.<anonymous>' type=java.util.LinkedHashMap<K1 of <root>.plus?, V1 of <root>.plus?> origin=null
                           p0: CALL 'public final fun <get-first> (): A of kotlin.Pair declared in kotlin.Pair' type=K1 of <root>.plus origin=GET_PROPERTY
                             $this: GET_VAR 'pair: kotlin.Pair<K1 of <root>.plus, V1 of <root>.plus> declared in <root>.plus' type=kotlin.Pair<K1 of <root>.plus, V1 of <root>.plus> origin=null

compiler/testData/ir/irText/stubs/javaEnum.fir.txt

@@ -1,10 +1,10 @@
 FILE fqName:<root> fileName:/javaEnum.kt
   PROPERTY name:test visibility:public modality:FINAL [val]
-    FIELD PROPERTY_BACKING_FIELD name:test type:<root>.JEnum visibility:private [final,static]
+    FIELD PROPERTY_BACKING_FIELD name:test type:@[FlexibleNullability] <root>.JEnum visibility:private [final,static]
       EXPRESSION_BODY
-        GET_ENUM 'ENUM_ENTRY IR_EXTERNAL_JAVA_DECLARATION_STUB name:ONE' type=<root>.JEnum
+        GET_ENUM 'ENUM_ENTRY IR_EXTERNAL_JAVA_DECLARATION_STUB name:ONE' type=@[FlexibleNullability] <root>.JEnum
-    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test> visibility:public modality:FINAL <> () returnType:<root>.JEnum
+    FUN DEFAULT_PROPERTY_ACCESSOR name:<get-test> visibility:public modality:FINAL <> () returnType:@[FlexibleNullability] <root>.JEnum
       correspondingProperty: PROPERTY name:test visibility:public modality:FINAL [val]
       BLOCK_BODY
-        RETURN type=kotlin.Nothing from='public final fun <get-test> (): <root>.JEnum declared in <root>'
+        RETURN type=kotlin.Nothing from='public final fun <get-test> (): @[FlexibleNullability] <root>.JEnum declared in <root>'
-          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test type:<root>.JEnum visibility:private [final,static]' type=<root>.JEnum origin=null
+          GET_FIELD 'FIELD PROPERTY_BACKING_FIELD name:test type:@[FlexibleNullability] <root>.JEnum visibility:private [final,static]' type=@[FlexibleNullability] <root>.JEnum origin=null

compiler/testData/ir/irText/types/asOnPlatformType.fir.txt

@@ -14,11 +14,11 @@ FILE fqName:<root> fileName:/asOnPlatformType.kt
           <T>: kotlin.String?
           $receiver: GET_VAR 'val nonnullStr: kotlin.String? [val] declared in <root>.test' type=kotlin.String? origin=null
       TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
-        CALL 'public final fun fooN <T> (): T of <root>.fooN? [inline] declared in <root>' type=kotlin.String? origin=null
+        CALL 'public final fun fooN <T> (): T of <root>.fooN? [inline] declared in <root>' type=@[FlexibleNullability] kotlin.String? origin=null
           <T>: kotlin.String?
           $receiver: GET_VAR 'val nullStr: kotlin.String? [val] declared in <root>.test' type=kotlin.String? origin=null
       TYPE_OP type=kotlin.Unit origin=IMPLICIT_COERCION_TO_UNIT typeOperand=kotlin.Unit
-        CALL 'public final fun fooN <T> (): T of <root>.fooN? [inline] declared in <root>' type=kotlin.String? origin=null
+        CALL 'public final fun fooN <T> (): T of <root>.fooN? [inline] declared in <root>' type=@[FlexibleNullability] kotlin.String? origin=null
           <T>: kotlin.String?
           $receiver: GET_VAR 'val nonnullStr: kotlin.String? [val] declared in <root>.test' type=kotlin.String? origin=null
   FUN name:foo visibility:public modality:FINAL <T> ($receiver:T of <root>.foo) returnType:T of <root>.foo [inline]

compiler/testData/ir/irText/types/nullChecks/enhancedNullabilityInDestructuringAssignment.fir.txt

@@ -131,42 +131,43 @@ FILE fqName:<root> fileName:/enhancedNullabilityInDestructuringAssignment.kt
         y: GET_VAR 'val y: kotlin.Int [val] declared in <root>.test1' type=kotlin.Int origin=null
   FUN name:test2 visibility:public modality:FINAL <> () returnType:kotlin.Unit
     BLOCK_BODY
-      VAR IR_TEMPORARY_VARIABLE name:tmp_1 type:<root>.Q<kotlin.String, kotlin.String?>? [val]
+      VAR IR_TEMPORARY_VARIABLE name:tmp_1 type:<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? [val]
-        CALL 'public open fun notNullComponents (): <root>.Q<kotlin.String, kotlin.String?>? declared in <root>.J' type=<root>.Q<kotlin.String, kotlin.String?>? origin=null
+        CALL 'public open fun notNullComponents (): <root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? declared in <root>.J' type=<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? origin=null
-      VAR name:x type:kotlin.String [val]
+      VAR name:x type:@[FlexibleNullability] kotlin.String [val]
-        CALL 'public final fun component1 (): T1 of <root>.Q [operator] declared in <root>.Q' type=kotlin.String origin=null
+        CALL 'public final fun component1 (): T1 of <root>.Q [operator] declared in <root>.Q' type=@[FlexibleNullability] kotlin.String origin=null
-          $this: GET_VAR 'val tmp_1: <root>.Q<kotlin.String, kotlin.String?>? [val] declared in <root>.test2' type=<root>.Q<kotlin.String, kotlin.String?>? origin=null
+          $this: GET_VAR 'val tmp_1: <root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? [val] declared in <root>.test2' type=<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? origin=null
       VAR name:y type:kotlin.String? [val]
         CALL 'public final fun component2 (): T2 of <root>.Q [operator] declared in <root>.Q' type=kotlin.String? origin=null
-          $this: GET_VAR 'val tmp_1: <root>.Q<kotlin.String, kotlin.String?>? [val] declared in <root>.test2' type=<root>.Q<kotlin.String, kotlin.String?>? origin=null
+          $this: GET_VAR 'val tmp_1: <root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? [val] declared in <root>.test2' type=<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? origin=null
       CALL 'public final fun use (x: kotlin.Any, y: kotlin.Any): kotlin.Unit declared in <root>' type=kotlin.Unit origin=null
-        x: GET_VAR 'val x: kotlin.String [val] declared in <root>.test2' type=kotlin.String origin=null
+        x: GET_VAR 'val x: @[FlexibleNullability] kotlin.String [val] declared in <root>.test2' type=@[FlexibleNullability] kotlin.String origin=null
         y: GET_VAR 'val y: kotlin.String? [val] declared in <root>.test2' type=kotlin.String? origin=null
   FUN name:test2Desugared visibility:public modality:FINAL <> () returnType:kotlin.Unit
     BLOCK_BODY
-      VAR name:tmp type:<root>.Q<kotlin.String, kotlin.String?>? [val]
+      VAR name:tmp type:<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? [val]
-        CALL 'public open fun notNullComponents (): <root>.Q<kotlin.String, kotlin.String?>? declared in <root>.J' type=<root>.Q<kotlin.String, kotlin.String?>? origin=null
+        CALL 'public open fun notNullComponents (): <root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? declared in <root>.J' type=<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? origin=null
-      VAR name:x type:kotlin.String [val]
+      VAR name:x type:@[FlexibleNullability] kotlin.String [val]
-        CALL 'public final fun component1 (): T1 of <root>.Q [operator] declared in <root>.Q' type=kotlin.String origin=null
+        CALL 'public final fun component1 (): T1 of <root>.Q [operator] declared in <root>.Q' type=@[FlexibleNullability] kotlin.String origin=null
-          $this: GET_VAR 'val tmp: <root>.Q<kotlin.String, kotlin.String?>? [val] declared in <root>.test2Desugared' type=<root>.Q<kotlin.String, kotlin.String?>? origin=null
+          $this: GET_VAR 'val tmp: <root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? [val] declared in <root>.test2Desugared' type=<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? origin=null
       VAR name:y type:kotlin.String? [val]
         CALL 'public final fun component2 (): T2 of <root>.Q [operator] declared in <root>.Q' type=kotlin.String? origin=null
-          $this: GET_VAR 'val tmp: <root>.Q<kotlin.String, kotlin.String?>? [val] declared in <root>.test2Desugared' type=<root>.Q<kotlin.String, kotlin.String?>? origin=null
+          $this: GET_VAR 'val tmp: <root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? [val] declared in <root>.test2Desugared' type=<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>? origin=null
       CALL 'public final fun use (x: kotlin.Any, y: kotlin.Any): kotlin.Unit declared in <root>' type=kotlin.Unit origin=null
-        x: GET_VAR 'val x: kotlin.String [val] declared in <root>.test2Desugared' type=kotlin.String origin=null
+        x: GET_VAR 'val x: @[FlexibleNullability] kotlin.String [val] declared in <root>.test2Desugared' type=@[FlexibleNullability] kotlin.String origin=null
         y: GET_VAR 'val y: kotlin.String? [val] declared in <root>.test2Desugared' type=kotlin.String? origin=null
   FUN name:test3 visibility:public modality:FINAL <> () returnType:kotlin.Unit
     BLOCK_BODY
-      VAR IR_TEMPORARY_VARIABLE name:tmp_2 type:<root>.Q<kotlin.String, kotlin.String?> [val]
+      VAR IR_TEMPORARY_VARIABLE name:tmp_2 type:<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?> [val]
-        CALL 'public open fun notNullQAndComponents (): <root>.Q<kotlin.String, kotlin.String?> declared in <root>.J' type=<root>.Q<kotlin.String, kotlin.String?> origin=null
+        TYPE_OP type=<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?> origin=IMPLICIT_NOTNULL typeOperand=<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?>
-      VAR name:x type:kotlin.String [val]
+          CALL 'public open fun notNullQAndComponents (): @[EnhancedNullability] <root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?> declared in <root>.J' type=@[EnhancedNullability] <root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?> origin=null
-        CALL 'public final fun component1 (): T1 of <root>.Q [operator] declared in <root>.Q' type=kotlin.String origin=null
+      VAR name:x type:@[FlexibleNullability] kotlin.String [val]
-          $this: GET_VAR 'val tmp_2: <root>.Q<kotlin.String, kotlin.String?> [val] declared in <root>.test3' type=<root>.Q<kotlin.String, kotlin.String?> origin=null
+        CALL 'public final fun component1 (): T1 of <root>.Q [operator] declared in <root>.Q' type=@[FlexibleNullability] kotlin.String origin=null
+          $this: GET_VAR 'val tmp_2: <root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?> [val] declared in <root>.test3' type=<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?> origin=null
       VAR name:y type:kotlin.String? [val]
         CALL 'public final fun component2 (): T2 of <root>.Q [operator] declared in <root>.Q' type=kotlin.String? origin=null
-          $this: GET_VAR 'val tmp_2: <root>.Q<kotlin.String, kotlin.String?> [val] declared in <root>.test3' type=<root>.Q<kotlin.String, kotlin.String?> origin=null
+          $this: GET_VAR 'val tmp_2: <root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?> [val] declared in <root>.test3' type=<root>.Q<@[FlexibleNullability] kotlin.String, kotlin.String?> origin=null
       CALL 'public final fun use (x: kotlin.Any, y: kotlin.Any): kotlin.Unit declared in <root>' type=kotlin.Unit origin=null
-        x: GET_VAR 'val x: kotlin.String [val] declared in <root>.test3' type=kotlin.String origin=null
+        x: GET_VAR 'val x: @[FlexibleNullability] kotlin.String [val] declared in <root>.test3' type=@[FlexibleNullability] kotlin.String origin=null
         y: GET_VAR 'val y: kotlin.String? [val] declared in <root>.test3' type=kotlin.String? origin=null
   FUN name:test4 visibility:public modality:FINAL <> () returnType:kotlin.Unit
     BLOCK_BODY

compiler/testData/loadJava/compiledJava/ArrayInGenericArguments.fir.txt

@@ -1,9 +1,9 @@
 public open class ArrayInGenericArguments : R|kotlin/Any| {
-    public final static field X: R|ft<ArrayInGenericArguments.DataKey<ft<kotlin/Array<ft<kotlin/String, kotlin/String?>!>, kotlin/Array<out ft<kotlin/String, kotlin/String?>!>?>!>, ArrayInGenericArguments.DataKey<ft<kotlin/Array<ft<kotlin/String, kotlin/String?>!>, kotlin/Array<out ft<kotlin/String, kotlin/String?>!>?>!>?>!|
+    public final static field X: R|ft<@FlexibleNullability ArrayInGenericArguments.DataKey<ft<@FlexibleNullability kotlin/Array<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>, kotlin/Array<out ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?>!>, ArrayInGenericArguments.DataKey<ft<@FlexibleNullability kotlin/Array<ft<@FlexibleNullability kotlin/String, kotlin/String?>!>, kotlin/Array<out ft<@FlexibleNullability kotlin/String, kotlin/String?>!>?>!>?>!|
 
-    public final static field Y: R|ft<ArrayInGenericArguments.DataKey<ft<kotlin/IntArray, kotlin/IntArray?>!>, ArrayInGenericArguments.DataKey<ft<kotlin/IntArray, kotlin/IntArray?>!>?>!|
+    public final static field Y: R|ft<@FlexibleNullability ArrayInGenericArguments.DataKey<ft<@FlexibleNullability kotlin/IntArray, kotlin/IntArray?>!>, ArrayInGenericArguments.DataKey<ft<@FlexibleNullability kotlin/IntArray, kotlin/IntArray?>!>?>!|
 
-    public final static field Z: R|ft<ArrayInGenericArguments.DataKey<out ft<kotlin/Array<ft<kotlin/CharSequence, kotlin/CharSequence?>!>, kotlin/Array<out ft<kotlin/CharSequence, kotlin/CharSequence?>!>?>!>, ArrayInGenericArguments.DataKey<out ft<kotlin/Array<ft<kotlin/CharSequence, kotlin/CharSequence?>!>, kotlin/Array<out ft<kotlin/CharSequence, kotlin/CharSequence?>!>?>!>?>!|
+    public final static field Z: R|ft<@FlexibleNullability ArrayInGenericArguments.DataKey<out ft<@FlexibleNullability kotlin/Array<ft<@FlexibleNullability kotlin/CharSequence, kotlin/CharSequence?>!>, kotlin/Array<out ft<@FlexibleNullability kotlin/CharSequence, kotlin/CharSequence?>!>?>!>, ArrayInGenericArguments.DataKey<out ft<@FlexibleNullability kotlin/Array<ft<@FlexibleNullability kotlin/CharSequence, kotlin/CharSequence?>!>, kotlin/Array<out ft<@FlexibleNullability kotlin/CharSequence, kotlin/CharSequence?>!>?>!>?>!|
 
     public constructor(): R|ArrayInGenericArguments|
 

compiler/testData/loadJava/compiledJava/ArrayTypeVariance.fir.txt

@@ -1,5 +1,5 @@
 public final class ArrayTypeVariance : R|kotlin/Any| {
-    public final fun toArray(p0: R|ft<kotlin/Array<ft<kotlin/Any, kotlin/Any?>!>, kotlin/Array<out ft<kotlin/Any, kotlin/Any?>!>?>!|): R|ft<kotlin/Array<ft<kotlin/Any, kotlin/Any?>!>, kotlin/Array<out ft<kotlin/Any, kotlin/Any?>!>?>!|
+    public final fun toArray(p0: R|ft<@FlexibleNullability kotlin/Array<ft<@FlexibleNullability kotlin/Any, kotlin/Any?>!>, kotlin/Array<out ft<@FlexibleNullability kotlin/Any, kotlin/Any?>!>?>!|): R|ft<@FlexibleNullability kotlin/Array<ft<@FlexibleNullability kotlin/Any, kotlin/Any?>!>, kotlin/Array<out ft<@FlexibleNullability kotlin/Any, kotlin/Any?>!>?>!|
 
     public constructor(): R|test/ArrayTypeVariance|
 

compiler/testData/loadJava/compiledJava/ClassWithTypePExtendsIterableP.fir.txt

@@ -1,4 +1,4 @@
-public abstract class ClassWithTypePExtendsIterableP<P : R|ft<kotlin/Any, kotlin/Any?>!|> : R|kotlin/Any|, R|kotlin/collections/MutableIterable<ft<P, P?>!>| {
+public abstract class ClassWithTypePExtendsIterableP<P : R|ft<kotlin/Any, kotlin/Any?>!|> : R|kotlin/Any|, R|kotlin/collections/MutableIterable<ft<@FlexibleNullability P, P?>!>| {
     public constructor<P : R|ft<kotlin/Any, kotlin/Any?>!|>(): R|test/ClassWithTypePExtendsIterableP<P>|
 
 }

compiler/testData/loadJava/compiledJava/ClassWithTypePP.fir.txt

@@ -1,4 +1,4 @@
-public final class ClassWithTypePP<P : R|ft<kotlin/Any, kotlin/Any?>!|, Q : R|ft<P, P?>!|> : R|kotlin/Any| {
+public final class ClassWithTypePP<P : R|ft<kotlin/Any, kotlin/Any?>!|, Q : R|ft<@FlexibleNullability P, P?>!|> : R|kotlin/Any| {
-    public constructor<P : R|ft<kotlin/Any, kotlin/Any?>!|, Q : R|ft<P, P?>!|>(): R|test/ClassWithTypePP<P, Q>|
+    public constructor<P : R|ft<kotlin/Any, kotlin/Any?>!|, Q : R|ft<@FlexibleNullability P, P?>!|>(): R|test/ClassWithTypePP<P, Q>|
 
 }

compiler/testData/loadJava/compiledJava/ClassWithTypePRefNext.fir.txt

@@ -1,4 +1,4 @@
-public open class ClassWithTypePRefNext<R : R|ft<kotlin/collections/MutableIterable<ft<P, P?>!>, kotlin/collections/Iterable<ft<P, P?>!>?>!|, P : R|ft<kotlin/Any, kotlin/Any?>!|> : R|kotlin/Any| {
+public open class ClassWithTypePRefNext<R : R|ft<@FlexibleNullability kotlin/collections/MutableIterable<ft<@FlexibleNullability P, P?>!>, kotlin/collections/Iterable<ft<@FlexibleNullability P, P?>!>?>!|, P : R|ft<kotlin/Any, kotlin/Any?>!|> : R|kotlin/Any| {
-    public constructor<R : R|ft<kotlin/collections/MutableIterable<ft<P, P?>!>, kotlin/collections/Iterable<ft<P, P?>!>?>!|, P : R|ft<kotlin/Any, kotlin/Any?>!|>(): R|test/ClassWithTypePRefNext<R, P>|
+    public constructor<R : R|ft<@FlexibleNullability kotlin/collections/MutableIterable<ft<@FlexibleNullability P, P?>!>, kotlin/collections/Iterable<ft<@FlexibleNullability P, P?>!>?>!|, P : R|ft<kotlin/Any, kotlin/Any?>!|>(): R|test/ClassWithTypePRefNext<R, P>|
 
 }

compiler/testData/loadJava/compiledJava/ClassWithTypePRefSelf.fir.txt

@@ -1,4 +1,4 @@
-public final class ClassWithTypePRefSelf<P : R|ft<kotlin/Enum<ft<P, P?>!>, kotlin/Enum<ft<P, P?>!>?>!|> : R|kotlin/Any| {
+public final class ClassWithTypePRefSelf<P : R|ft<@FlexibleNullability kotlin/Enum<ft<@FlexibleNullability P, P?>!>, kotlin/Enum<ft<@FlexibleNullability P, P?>!>?>!|> : R|kotlin/Any| {
-    public constructor<P : R|ft<kotlin/Enum<ft<P, P?>!>, kotlin/Enum<ft<P, P?>!>?>!|>(): R|test/ClassWithTypePRefSelf<P>|
+    public constructor<P : R|ft<@FlexibleNullability kotlin/Enum<ft<@FlexibleNullability P, P?>!>, kotlin/Enum<ft<@FlexibleNullability P, P?>!>?>!|>(): R|test/ClassWithTypePRefSelf<P>|
 
 }

compiler/testData/loadJava/compiledJava/ClassWithTypePRefSelfAndClass.fir.txt

@@ -1,4 +1,4 @@
-public final class ClassWithTypePRefSelfAndClass<P : R|ft<test/ClassWithTypePRefSelfAndClass<ft<P, P?>!>, test/ClassWithTypePRefSelfAndClass<ft<P, P?>!>?>!|> : R|kotlin/Any| {
+public final class ClassWithTypePRefSelfAndClass<P : R|ft<@FlexibleNullability test/ClassWithTypePRefSelfAndClass<ft<@FlexibleNullability P, P?>!>, test/ClassWithTypePRefSelfAndClass<ft<@FlexibleNullability P, P?>!>?>!|> : R|kotlin/Any| {
-    public constructor<P : R|ft<test/ClassWithTypePRefSelfAndClass<ft<P, P?>!>, test/ClassWithTypePRefSelfAndClass<ft<P, P?>!>?>!|>(): R|test/ClassWithTypePRefSelfAndClass<P>|
+    public constructor<P : R|ft<@FlexibleNullability test/ClassWithTypePRefSelfAndClass<ft<@FlexibleNullability P, P?>!>, test/ClassWithTypePRefSelfAndClass<ft<@FlexibleNullability P, P?>!>?>!|>(): R|test/ClassWithTypePRefSelfAndClass<P>|
 
 }

compiler/testData/loadJava/compiledJava/FieldOfArrayType.fir.txt

@@ -1,5 +1,5 @@
 public open class FieldOfArrayType : R|kotlin/Any| {
-    public open field files: R|ft<kotlin/Array<ft<java/io/File, java/io/File?>!>, kotlin/Array<out ft<java/io/File, java/io/File?>!>?>!|
+    public open field files: R|ft<@FlexibleNullability kotlin/Array<ft<@FlexibleNullability java/io/File, java/io/File?>!>, kotlin/Array<out ft<@FlexibleNullability java/io/File, java/io/File?>!>?>!|
 
     public constructor(): R|test/FieldOfArrayType|
 

compiler/testData/loadJava/compiledJava/InnerClassTypeMultipleGeneric.fir.txt

@@ -1,5 +1,5 @@
 public open class InnerClassTypeMultipleGeneric : R|kotlin/Any| {
-    public open fun staticType(): R|ft<test/InnerClassTypeMultipleGeneric.Outer.Inner<ft<kotlin/Byte, kotlin/Byte?>!, ft<kotlin/Char, kotlin/Char?>!, ft<kotlin/Boolean, kotlin/Boolean?>!>, test/InnerClassTypeMultipleGeneric.Outer.Inner<ft<kotlin/Byte, kotlin/Byte?>!, ft<kotlin/Char, kotlin/Char?>!, ft<kotlin/Boolean, kotlin/Boolean?>!>?>!|
+    public open fun staticType(): R|ft<@FlexibleNullability test/InnerClassTypeMultipleGeneric.Outer.Inner<ft<@FlexibleNullability kotlin/Byte, kotlin/Byte?>!, ft<@FlexibleNullability kotlin/Char, kotlin/Char?>!, ft<@FlexibleNullability kotlin/Boolean, kotlin/Boolean?>!>, test/InnerClassTypeMultipleGeneric.Outer.Inner<ft<@FlexibleNullability kotlin/Byte, kotlin/Byte?>!, ft<@FlexibleNullability kotlin/Char, kotlin/Char?>!, ft<@FlexibleNullability kotlin/Boolean, kotlin/Boolean?>!>?>!|
 
     public constructor(): R|test/InnerClassTypeMultipleGeneric|
 

compiler/testData/loadJava/compiledJava/IntrinsicCompanionObject.fir.txt

@@ -1,12 +1,12 @@
 public abstract interface IntrinsicCompanionObject : R|kotlin/Any| {
-    public abstract fun testInt(i: R|ft<kotlin/Int.Companion, kotlin/Int.Companion?>!|): R|kotlin/Unit|
+    public abstract fun testInt(i: R|ft<@FlexibleNullability kotlin/Int.Companion, kotlin/Int.Companion?>!|): R|kotlin/Unit|
 
-    public abstract fun testChar(c: R|ft<kotlin/Char.Companion, kotlin/Char.Companion?>!|): R|kotlin/Unit|
+    public abstract fun testChar(c: R|ft<@FlexibleNullability kotlin/Char.Companion, kotlin/Char.Companion?>!|): R|kotlin/Unit|
 
-    public abstract fun testString(s: R|ft<kotlin/String.Companion, kotlin/String.Companion?>!|): R|kotlin/Unit|
+    public abstract fun testString(s: R|ft<@FlexibleNullability kotlin/String.Companion, kotlin/String.Companion?>!|): R|kotlin/Unit|
 
-    public abstract fun testBoolean(b: R|ft<kotlin/Boolean.Companion, kotlin/Boolean.Companion?>!|): R|kotlin/Unit|
+    public abstract fun testBoolean(b: R|ft<@FlexibleNullability kotlin/Boolean.Companion, kotlin/Boolean.Companion?>!|): R|kotlin/Unit|
 
-    public abstract fun testEnum(e: R|ft<kotlin/Enum.Companion, kotlin/Enum.Companion?>!|): R|kotlin/Unit|
+    public abstract fun testEnum(e: R|ft<@FlexibleNullability kotlin/Enum.Companion, kotlin/Enum.Companion?>!|): R|kotlin/Unit|
 
 }

compiler/testData/loadJava/compiledJava/MethodTypePOneUpperBound.fir.txt

@@ -1,5 +1,5 @@
 public open class MethodTypePOneUpperBound : R|kotlin/Any| {
-    public open fun <T : R|ft<kotlin/Cloneable, kotlin/Cloneable?>!|> bar(): R|kotlin/Unit|
+    public open fun <T : R|ft<@FlexibleNullability kotlin/Cloneable, kotlin/Cloneable?>!|> bar(): R|kotlin/Unit|
 
     public constructor(): R|test/MethodTypePOneUpperBound|
 

compiler/testData/loadJava/compiledJava/MethodTypePTwoUpperBounds.fir.txt

@@ -1,5 +1,5 @@
 public open class MethodTypePTwoUpperBounds : R|kotlin/Any| {
-    public open fun <T : R|ft<kotlin/Cloneable, kotlin/Cloneable?>!|, R|ft<java/lang/Runnable, java/lang/Runnable?>!|> foo(): R|kotlin/Unit|
+    public open fun <T : R|ft<@FlexibleNullability kotlin/Cloneable, kotlin/Cloneable?>!|, R|ft<@FlexibleNullability java/lang/Runnable, java/lang/Runnable?>!|> foo(): R|kotlin/Unit|
 
     public constructor(): R|test/MethodTypePTwoUpperBounds|
 

compiler/testData/loadJava/compiledJava/MethodWithTypePP.fir.txt

@@ -1,5 +1,5 @@
 public final class MethodWithTypePP : R|kotlin/Any| {
-    public final fun <P : R|ft<kotlin/Any, kotlin/Any?>!|, Q : R|ft<P, P?>!|> f(): R|kotlin/Unit|
+    public final fun <P : R|ft<kotlin/Any, kotlin/Any?>!|, Q : R|ft<@FlexibleNullability P, P?>!|> f(): R|kotlin/Unit|
 
     public constructor(): R|test/MethodWithTypePP|
 

compiler/testData/loadJava/compiledJava/MethodWithTypePRefClassP.fir.txt

@@ -1,5 +1,5 @@
 public open class MethodWithTypePRefClassP<P : R|ft<kotlin/Any, kotlin/Any?>!|> : R|kotlin/Any| {
-    public final fun <Q : R|ft<P, P?>!|> f(): R|kotlin/Unit|
+    public final fun <Q : R|ft<@FlexibleNullability P, P?>!|> f(): R|kotlin/Unit|
 
     public constructor<P : R|ft<kotlin/Any, kotlin/Any?>!|>(): R|test/MethodWithTypePRefClassP<P>|
 

compiler/testData/loadJava/compiledJava/MethosWithPRefTP.fir.txt

@@ -1,5 +1,5 @@
 public final class MethosWithPRefTP : R|kotlin/Any| {
-    public final fun <P : R|ft<kotlin/Any, kotlin/Any?>!|> f(p: R|ft<P, P?>!|): R|kotlin/Unit|
+    public final fun <P : R|ft<kotlin/Any, kotlin/Any?>!|> f(p: R|ft<@FlexibleNullability P, P?>!|): R|kotlin/Unit|
 
     public constructor(): R|test/MethosWithPRefTP|
 

compiler/testData/loadJava/compiledJava/MyException.fir.txt

@@ -1,4 +1,4 @@
 public open class MyException : R|kotlin/Any| {
-    public constructor(message: R|ft<kotlin/String, kotlin/String?>!|, cause: R|ft<kotlin/Throwable, kotlin/Throwable?>!|): R|test/MyException|
+    public constructor(message: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|, cause: R|ft<@FlexibleNullability kotlin/Throwable, kotlin/Throwable?>!|): R|test/MyException|
 
 }

compiler/testData/loadJava/compiledJava/PackageLocalVisibility.fir.txt

@@ -1,11 +1,11 @@
 public open class Frame : R|kotlin/Any| {
-    public/*package*/ open field accessibleContext: R|ft<kotlin/String, kotlin/String?>!|
+    public/*package*/ open field accessibleContext: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
     public constructor(): R|awt/Frame|
 
 }
 public open class JFrame : R|awt/Frame| {
-    protected/*protected and package*/ open field accessibleContext: R|ft<kotlin/String, kotlin/String?>!|
+    protected/*protected and package*/ open field accessibleContext: R|ft<@FlexibleNullability kotlin/String, kotlin/String?>!|
 
     public constructor(): R|test/JFrame|
 

compiler/testData/loadJava/compiledJava/RemoveRedundantProjectionKind.fir.txt

@@ -1,6 +1,6 @@
 public abstract interface RemoveRedundantProjectionKind : R|kotlin/Any| {
-    public abstract fun f(collection: R|ft<kotlin/collections/MutableCollection<out ft<kotlin/CharSequence, kotlin/CharSequence?>!>, kotlin/collections/Collection<out ft<kotlin/CharSequence, kotlin/CharSequence?>!>?>!|): R|kotlin/Unit|
+    public abstract fun f(collection: R|ft<@FlexibleNullability kotlin/collections/MutableCollection<out ft<@FlexibleNullability kotlin/CharSequence, kotlin/CharSequence?>!>, kotlin/collections/Collection<out ft<@FlexibleNullability kotlin/CharSequence, kotlin/CharSequence?>!>?>!|): R|kotlin/Unit|
 
-    public abstract fun f(comparator: R|ft<kotlin/Comparable<in ft<kotlin/CharSequence, kotlin/CharSequence?>!>, kotlin/Comparable<in ft<kotlin/CharSequence, kotlin/CharSequence?>!>?>!|): R|kotlin/Unit|
+    public abstract fun f(comparator: R|ft<@FlexibleNullability kotlin/Comparable<in ft<@FlexibleNullability kotlin/CharSequence, kotlin/CharSequence?>!>, kotlin/Comparable<in ft<@FlexibleNullability kotlin/CharSequence, kotlin/CharSequence?>!>?>!|): R|kotlin/Unit|
 
 }