[FIR] Fix processing constructors of sealed classes

- Allow declaring protected constructors in sealed classes
- Make default visibility of sealed class constructor `protected`

KT-44861
KT-44865

compiler/fir/analysis-tests/testData/loadCompiledKotlin/annotations/classMembers/HiddenConstructorWithInlineClassParameters.txt

@@ -12,7 +12,7 @@ public sealed class Sealed : R|kotlin/Any| {
     public final val z: R|test/Z|
         public get(): R|test/Z|
 
-    @R|test/Ann|() internal constructor(@R|test/Ann|() z: R|test/Z|): R|test/Sealed|
+    @R|test/Ann|() protected constructor(@R|test/Ann|() z: R|test/Z|): R|test/Sealed|
 
 }
 

compiler/fir/analysis-tests/testData/loadCompiledKotlin/class/SealedClass.txt

@@ -14,7 +14,7 @@ public sealed class SealedClass : R|kotlin/Any| {
 
     }
 
-    internal constructor(): R|test/SealedClass|
+    protected constructor(): R|test/SealedClass|
 
 }
 

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

@@ -44,7 +44,7 @@ FILE: constantValues.kt
         }
 
         public sealed class Value : R|kotlin/Any| {
-            private constructor(): R|KClassValue.Value| {
+            protected constructor(): R|KClassValue.Value| {
                 super<R|kotlin/Any|>()
             }
 

compiler/fir/analysis-tests/testData/resolve/diagnostics/incompatibleModifiers.fir.txt

@@ -30,13 +30,13 @@ FILE: incompatibleModifiers.kt
 
     }
     public final class F : R|kotlin/Any| {
-        private constructor(): R|F| {
+        protected constructor(): R|F| {
             super<R|kotlin/Any|>()
         }
 
     }
     public sealed class G : R|kotlin/Any| {
-        private constructor(): R|G| {
+        protected constructor(): R|G| {
             super<R|kotlin/Any|>()
         }
 
@@ -57,7 +57,7 @@ FILE: incompatibleModifiers.kt
 
     }
     public sealed data class I : R|kotlin/Any| {
-        private constructor(i: R|kotlin/Int|): R|I| {
+        protected constructor(i: R|kotlin/Int|): R|I| {
             super<R|kotlin/Any|>()
         }
 
@@ -126,7 +126,7 @@ FILE: incompatibleModifiers.kt
         }
 
         public sealed inner class Z : R|kotlin/Any| {
-            private constructor(): R|X.Z| {
+            protected constructor(): R|X.Z| {
                 super<R|kotlin/Any|>()
             }
 

compiler/fir/analysis-tests/testData/resolve/diagnostics/redundantModifier.fir.txt

@@ -6,7 +6,7 @@ FILE: redundantModifier.kt
 
     }
     public sealed class B : R|kotlin/Any| {
-        private constructor(): R|B| {
+        protected constructor(): R|B| {
             super<R|kotlin/Any|>()
         }
 

compiler/fir/analysis-tests/testData/resolve/diagnostics/sealedClassConstructorCall.fir.txt

@@ -1,9 +1,9 @@
 FILE: sealedClassConstructorCall.kt
     public sealed class A : R|kotlin/Any| {
-        private constructor(): R|A| {
+        protected constructor(): R|A| {
             super<R|kotlin/Any|>()
         }
 
     }
-    public final val b: R|A| = R|/A.A|()
+    public final val b: R|A| = <HIDDEN: /A.A is invisible>#()
         public get(): R|A|

compiler/fir/analysis-tests/testData/resolve/diagnostics/sealedClassConstructorCall.kt

@@ -1,3 +1,3 @@
 sealed class A
 
-val b = <!SEALED_CLASS_CONSTRUCTOR_CALL{LT}!><!SEALED_CLASS_CONSTRUCTOR_CALL{PSI}!>A<!>()<!>
+val b = <!HIDDEN{LT}!><!HIDDEN{PSI}!>A<!>()<!>

compiler/fir/analysis-tests/testData/resolve/diagnostics/sealedSupertype.fir.txt

@@ -1,6 +1,6 @@
 FILE: sealedSupertype.kt
     public sealed class A : R|kotlin/Any| {
-        private constructor(): R|A| {
+        protected constructor(): R|A| {
             super<R|kotlin/Any|>()
         }
 
@@ -22,7 +22,7 @@ FILE: sealedSupertype.kt
 
     }
     public sealed class P : R|kotlin/Any| {
-        private constructor(): R|P| {
+        protected constructor(): R|P| {
             super<R|kotlin/Any|>()
         }
 

compiler/fir/analysis-tests/testData/resolve/exhaustiveness/negative/missingSealedInheritor.fir.txt

@@ -1,6 +1,6 @@
 FILE: a.kt
     public sealed class Base : R|kotlin/Any| {
-        private constructor(): R|Base| {
+        protected constructor(): R|Base| {
             super<R|kotlin/Any|>()
         }
 

compiler/fir/analysis-tests/testData/resolve/exhaustiveness/positive/exhaustiveness_sealedClass.fir.txt

@@ -1,6 +1,6 @@
 FILE: exhaustiveness_sealedClass.kt
     public sealed class Base : R|kotlin/Any| {
-        private constructor(): R|Base| {
+        protected constructor(): R|Base| {
             super<R|kotlin/Any|>()
         }
 

compiler/fir/analysis-tests/testData/resolve/exhaustiveness/positive/exhaustiveness_sealedObject.fir.txt

@@ -1,6 +1,6 @@
 FILE: exhaustiveness_sealedObject.kt
     public sealed class A : R|kotlin/Any| {
-        private constructor(): R|A| {
+        protected constructor(): R|A| {
             super<R|kotlin/Any|>()
         }
 

compiler/fir/analysis-tests/testData/resolve/exhaustiveness/positive/exhaustiveness_sealedSubClass.fir.txt

@@ -1,12 +1,12 @@
 FILE: exhaustiveness_sealedSubClass.kt
     public sealed class A : R|kotlin/Any| {
-        private constructor(): R|A| {
+        protected constructor(): R|A| {
             super<R|kotlin/Any|>()
         }
 
     }
     public sealed class B : R|A| {
-        private constructor(): R|B| {
+        protected constructor(): R|B| {
             super<R|A|>()
         }
 
@@ -18,13 +18,13 @@ FILE: exhaustiveness_sealedSubClass.kt
 
     }
     public sealed class D : R|B| {
-        private constructor(): R|D| {
+        protected constructor(): R|D| {
             super<R|B|>()
         }
 
     }
     public sealed class E : R|B| {
-        private constructor(): R|E| {
+        protected constructor(): R|E| {
             super<R|B|>()
         }
 

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

@@ -5,7 +5,7 @@ FILE: classifierAccessFromCompanion.kt
         }
 
         public sealed class Function : R|kotlin/Any| {
-            private constructor(): R|Factory.Function| {
+            protected constructor(): R|Factory.Function| {
                 super<R|kotlin/Any|>()
             }
 

compiler/fir/analysis-tests/testData/resolve/extendedCheckers/RedundantVisibilityModifierChecker.fir.txt

@@ -111,7 +111,7 @@ FILE: RedundantVisibilityModifierChecker.kt
 
     }
     public sealed class G : R|kotlin/Any| {
-        private constructor(y: R|kotlin/Int|): R|G| {
+        protected constructor(y: R|kotlin/Int|): R|G| {
             super<R|kotlin/Any|>()
         }
 

compiler/fir/analysis-tests/testData/resolve/multifile/sealedStarImport.fir.txt

@@ -1,6 +1,6 @@
 FILE: test.kt
     public sealed class Test : R|kotlin/Any| {
-        private constructor(): R|test/Test| {
+        protected constructor(): R|test/Test| {
             super<R|kotlin/Any|>()
         }
 

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

@@ -1,6 +1,6 @@
 FILE: recursiveCallOnWhenWithSealedClass.kt
     public sealed class Maybe<T> : R|kotlin/Any| {
-        private constructor<T>(): R|Maybe<T>| {
+        protected constructor<T>(): R|Maybe<T>| {
             super<R|kotlin/Any|>()
         }
 

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

@@ -1,6 +1,6 @@
 FILE: sealedClass.kt
     public sealed class Foo : R|kotlin/Any| {
-        private constructor(value: R|kotlin/String|): R|Foo| {
+        protected constructor(value: R|kotlin/String|): R|Foo| {
             super<R|kotlin/Any|>()
         }
 

compiler/fir/analysis-tests/testData/resolve/smartcasts/kt37327.fir.txt

@@ -2,7 +2,7 @@ FILE: kt37327.kt
     public abstract interface Q : R|kotlin/Any| {
     }
     public sealed class A : R|Q| {
-        private constructor(): R|A| {
+        protected constructor(): R|A| {
             super<R|kotlin/Any|>()
         }
 

compiler/fir/analysis-tests/testData/resolve/smartcasts/lambdas/lambdaInWhenBranch.fir.txt

@@ -1,6 +1,6 @@
 FILE: lambdaInWhenBranch.kt
     private sealed class Sealed : R|kotlin/Any| {
-        private constructor(): R|Sealed| {
+        protected constructor(): R|Sealed| {
             super<R|kotlin/Any|>()
         }
 

compiler/fir/analysis-tests/testData/resolve/types/bareWithSubjectTypeAlias.fir.txt

@@ -1,6 +1,6 @@
 FILE: bareWithSubjectTypeAlias.kt
     public sealed class A<out T> : R|kotlin/Any| {
-        private constructor<out T>(): R|A<T>| {
+        protected constructor<out T>(): R|A<T>| {
             super<R|kotlin/Any|>()
         }