Raw FIR: make object/sealed/enum constructor visibility private

compiler/fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt

@@ -384,11 +384,19 @@ class RawFirBuilder(val session: FirSession, val stubMode: Boolean) {
                     superTypeCallEntry?.extractArgumentsTo(this)
                 }
             }
+
+            fun defaultVisibility() =
+                if (owner is KtObjectDeclaration || owner.hasModifier(SEALED_KEYWORD) || owner.hasModifier(ENUM_KEYWORD))
+                // TODO: sealed is FILE_PRIVATE (?) object / enum is HIDDEN (?)
+                    Visibilities.PRIVATE
+                else
+                    Visibilities.UNKNOWN
+
             val firConstructor = FirPrimaryConstructorImpl(
                 session,
                 this ?: owner,
                 FirFunctionSymbol(callableIdForClassConstructor()),
-                this?.visibility ?: Visibilities.UNKNOWN,
+                this?.visibility ?: defaultVisibility(),
                 this?.hasExpectModifier() ?: false,
                 this?.hasActualModifier() ?: false,
                 delegatedSelfTypeRef,

compiler/fir/psi2fir/testData/rawBuilder/declarations/enums.txt

@@ -1,6 +1,6 @@
 FILE: enums.kt
     public? final? enum class Order : kotlin/Enum {
-        public? constructor(): super<kotlin/Enum>()
+        private constructor(): super<kotlin/Enum>()
 
         public? final enum entry FIRST : kotlin/Any {
             public? constructor(): super<kotlin/Any>()
@@ -60,7 +60,7 @@ FILE: enums.kt
         public? abstract fun sayHello(): kotlin/Unit
 
         public? final? companion object Companion : kotlin/Any {
-            public? constructor(): super<kotlin/Any>()
+            private constructor(): super<kotlin/Any>()
 
             public? final? const val G: <implicit> = Double(6.67E-11)
                 public? get(): <implicit>

compiler/fir/psi2fir/testData/rawBuilder/declarations/enums2.txt

@@ -2,11 +2,11 @@ FILE: enums2.kt
     public? final? interface Some : kotlin/Any {
     }
     public? final? object O1 : Some {
-        public? constructor(): super<kotlin/Any>()
+        private constructor(): super<kotlin/Any>()
 
     }
     public? final? object O2 : Some {
-        public? constructor(): super<kotlin/Any>()
+        private constructor(): super<kotlin/Any>()
 
     }
     public? final? enum class SomeEnum : kotlin/Enum {

compiler/fir/psi2fir/testData/rawBuilder/declarations/nestedClass.txt

@@ -15,7 +15,7 @@ FILE: nestedClass.kt
         }
 
         public? final? object Obj : Base {
-            public? constructor(): super<Base>(String())
+            private constructor(): super<Base>(String())
 
         }
 

compiler/fir/psi2fir/testData/rawBuilder/expressions/locals.txt

@@ -18,7 +18,7 @@ FILE: locals.kt
         }
 
         lval code: <implicit> = object : Any {
-            public? constructor(): super<Any>()
+            private constructor(): super<Any>()
 
             public? final? fun foo(): <implicit> {
                 ^foo hashCode#()