[FIR] Handle explicitly private sealed class constructors properly

#KT-36850 Fixed

compiler/fir/lightTree/src/org/jetbrains/kotlin/fir/lightTree/converter/DeclarationsConverter.kt

@@ -6,7 +6,6 @@
 package org.jetbrains.kotlin.fir.lightTree.converter
 
 import com.intellij.lang.LighterASTNode
-import com.intellij.lang.LighterASTTokenNode
 import com.intellij.psi.TokenType
 import com.intellij.util.diff.FlyweightCapableTreeStructure
 import org.jetbrains.kotlin.KtNodeTypes.*
@@ -638,14 +637,12 @@ class DeclarationsConverter(
             extractArgumentsFrom(classWrapper.superTypeCallEntry, stubMode)
         }
 
-        val status = FirDeclarationStatusImpl(
-            if (primaryConstructor != null) modifiers.getVisibility() else defaultVisibility,
-            Modality.FINAL
-        ).apply {
+        val explicitVisibility = if (primaryConstructor != null) modifiers.getVisibility() else null
+        val status = FirDeclarationStatusImpl(explicitVisibility ?: defaultVisibility, Modality.FINAL).apply {
             isExpect = modifiers.hasExpect()
             isActual = modifiers.hasActual()
             isInner = classWrapper.isInner()
-            isFromSealedClass = classWrapper.isSealed()
+            isFromSealedClass = classWrapper.isSealed() && explicitVisibility !== Visibilities.PRIVATE
             isFromEnumClass = classWrapper.isEnum()
         }
 
@@ -711,11 +708,12 @@ class DeclarationsConverter(
             }
             else classWrapper.delegatedSelfTypeRef
 
-        val status = FirDeclarationStatusImpl(modifiers.getVisibility(), Modality.FINAL).apply {
+        val explicitVisibility = modifiers.getVisibility()
+        val status = FirDeclarationStatusImpl(explicitVisibility, Modality.FINAL).apply {
             isExpect = modifiers.hasExpect()
             isActual = modifiers.hasActual()
             isInner = classWrapper.isInner()
-            isFromSealedClass = classWrapper.isSealed()
+            isFromSealedClass = classWrapper.isSealed() && explicitVisibility !== Visibilities.PRIVATE
             isFromEnumClass = classWrapper.isEnum()
         }
 

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

@@ -472,11 +472,12 @@ class RawFirBuilder(
                 else -> Visibilities.UNKNOWN
             }
 
-            val status = FirDeclarationStatusImpl(this?.visibility ?: defaultVisibility(), Modality.FINAL).apply {
+            val explicitVisibility = this?.visibility
+            val status = FirDeclarationStatusImpl(explicitVisibility ?: defaultVisibility(), Modality.FINAL).apply {
                 isExpect = this@toFirConstructor?.hasExpectModifier() ?: false
                 isActual = this@toFirConstructor?.hasActualModifier() ?: false
                 isInner = owner.hasModifier(INNER_KEYWORD)
-                isFromSealedClass = owner.hasModifier(SEALED_KEYWORD)
+                isFromSealedClass = owner.hasModifier(SEALED_KEYWORD) && explicitVisibility !== Visibilities.PRIVATE
                 isFromEnumClass = owner.hasModifier(ENUM_KEYWORD)
             }
             return buildPrimaryConstructor {
@@ -846,11 +847,12 @@ class RawFirBuilder(
                 source = this@toFirConstructor.toFirSourceElement()
                 session = baseSession
                 returnTypeRef = delegatedSelfTypeRef
-                status = FirDeclarationStatusImpl(visibility, Modality.FINAL).apply {
+                val explicitVisibility = visibility
+                status = FirDeclarationStatusImpl(explicitVisibility, Modality.FINAL).apply {
                     isExpect = hasExpectModifier()
                     isActual = hasActualModifier()
                     isInner = owner.hasModifier(INNER_KEYWORD)
-                    isFromSealedClass = owner.hasModifier(SEALED_KEYWORD)
+                    isFromSealedClass = owner.hasModifier(SEALED_KEYWORD) && explicitVisibility !== Visibilities.PRIVATE
                     isFromEnumClass = owner.hasModifier(ENUM_KEYWORD)
                 }
                 symbol = FirConstructorSymbol(callableIdForClassConstructor())

compiler/fir/resolve/testData/resolve/sealedClass.kt

@@ -1,3 +1,10 @@
 sealed class Foo(val value: String)
 
 class Bar : Foo("OK")
+
+sealed class WithPrivateConstructor private constructor(val x: Int) {
+    private constructor() : this(42)
+}
+
+object First : <!INAPPLICABLE_CANDIDATE!>WithPrivateConstructor<!>() // error
+object Second : <!INAPPLICABLE_CANDIDATE!>WithPrivateConstructor<!>(0) // error

compiler/fir/resolve/testData/resolve/sealedClass.txt

@@ -14,3 +14,28 @@ FILE: sealedClass.kt
         }
 
     }
+    public sealed class WithPrivateConstructor : R|kotlin/Any| {
+        private constructor(x: R|kotlin/Int|): R|WithPrivateConstructor| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final val x: R|kotlin/Int| = R|<local>/x|
+            public get(): R|kotlin/Int|
+
+        private constructor(): R|WithPrivateConstructor| {
+            this<R|WithPrivateConstructor|>(Int(42))
+        }
+
+    }
+    public final object First : R|WithPrivateConstructor| {
+        private constructor(): R|First| {
+            super<R|WithPrivateConstructor|>()
+        }
+
+    }
+    public final object Second : R|WithPrivateConstructor| {
+        private constructor(): R|Second| {
+            super<R|WithPrivateConstructor|>(IntegerLiteral(0))
+        }
+
+    }