Error diagnostic for private classes in inline functions; Fix for KT-7545: IllegalAccessError when accessing private nested class through inlined function from different package

#KT-7545 Fixed

compiler/testData/codegen/boxInline/private/nestedInPrivateClass.1.kt

@@ -0,0 +1,7 @@
+import test.*
+
+fun box(): String {
+    return call {
+        "O"
+    }
+}

compiler/testData/codegen/boxInline/private/nestedInPrivateClass.2.kt

@@ -0,0 +1,18 @@
+package test
+
+private class S public constructor() {
+    class Z {
+        fun a(): String {
+            return "K"
+        }
+    }
+}
+// This function exposes S.Z which is a class nested into a private class S (package-private in the byte code)
+// It can be accessed outside the `test` package now that S.Z. is public in the byte code, but it may be changed later
+internal inline fun call(s: () -> String): String {
+    return s() + test().a()
+}
+
+private fun test(): S.Z {
+    return S.Z()
+}

compiler/testData/codegen/boxInline/private/privateClass.1.kt

@@ -0,0 +1,7 @@
+import test.*
+
+fun box(): String {
+    return call {
+        "O"
+    }
+}

compiler/testData/codegen/boxInline/private/privateClass.2.kt

@@ -0,0 +1,23 @@
+package test
+
+private class S {
+    fun a(): String {
+        return "K"
+    }
+}
+
+// This function exposes S which is a private class (package-private in the byte code)
+// It can be accessed outside the `test` package, which may lead to IllegalAccessError.
+// This behavior may be changed later
+internal inline fun call(s: () -> String): String {
+    val s = test()
+    return s() + test2(s)
+}
+
+private fun test(): S {
+    return S()
+}
+
+private fun test2(s: S): String {
+    return s.a()
+}

compiler/testData/codegen/boxInline/private/privateClassExtensionLambda.1.kt

@@ -0,0 +1,5 @@
+import test.*
+
+fun box(): String {
+    return call()
+}

compiler/testData/codegen/boxInline/private/privateClassExtensionLambda.2.kt

@@ -0,0 +1,25 @@
+package test
+
+private class S {
+    fun a(): String {
+        return "K"
+    }
+
+    // This function exposes S which is a private class (package-private in the byte code)
+    // It can be accessed outside the `test` package, which may lead to IllegalAccessError.
+    // This behavior may be changed later
+    internal inline fun call(s: S.() -> String): String {
+        return call2(s)
+    }
+}
+
+@Suppress("PRIVATE_CLASS_MEMBER_FROM_INLINE", "EXPOSED_PARAMETER_TYPE", "EXPOSED_RECEIVER_TYPE")
+internal inline fun S.call2(s: S.() -> String): String {
+    return s() + a()
+}
+
+internal fun call(): String {
+    return S().call {
+        "O"
+    }
+}

compiler/testData/diagnostics/tests/inline/nonPublicMember/inNonPublicClass.kt

@@ -1,4 +1,4 @@
-// !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER -UNUSED_VARIABLE -NOTHING_TO_INLINE
+// !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER -UNUSED_VARIABLE -NOTHING_TO_INLINE -INVISIBLE_PRIVATE_CLASS_MEMBER_FROM_INLINE
 private class Z public constructor(){
     public val publicProperty:Int = 12
     public fun publicFun() {}
@@ -14,7 +14,7 @@ internal inline fun testInternal() {
     Z().publicFun()
 }
 
-private class Z2 {
+internal class Z2 {
     private val privateProperty = 11;
 
     public val publicProperty:Int = 12
@@ -34,7 +34,7 @@ private class Z2 {
         Z2().privateFun()
     }
 
-    inline fun testInternal() {
+    internal inline fun testInternal() {
         privateProperty
         privateFun()
         publicProperty

compiler/testData/diagnostics/tests/inline/nonPublicMember/inNonPublicClass.txt

@@ -12,7 +12,7 @@ private final class Z {
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-private final class Z2 {
+internal final class Z2 {
     public constructor Z2()
     private final val privateProperty: kotlin.Int = 11
     public final val publicProperty: kotlin.Int = 12

compiler/testData/diagnostics/tests/inline/nonPublicMember/inNonPublicInnerClass.kt

@@ -1,5 +1,5 @@
 // !DIAGNOSTICS: -UNUSED_EXPRESSION -UNUSED_PARAMETER -UNUSED_VARIABLE -NOTHING_TO_INLINE
-private class Z2 {
+internal class Z2 {
     private val privateProperty = 11;
 
     public val publicProperty:Int = 12
@@ -8,7 +8,7 @@ private class Z2 {
 
     public fun publicFun() {}
 
-    private inner class ZInner {
+    internal inner class ZInner {
         public inline fun test() {
             privateProperty
             privateFun()
@@ -21,7 +21,7 @@ private class Z2 {
             Z2().privateFun()
         }
 
-        inline fun testInternal() {
+        internal inline fun testInternal() {
             privateProperty
             privateFun()
             publicFun()

compiler/testData/diagnostics/tests/inline/nonPublicMember/inNonPublicInnerClass.txt

@@ -1,6 +1,6 @@
 package
 
-private final class Z2 {
+internal final class Z2 {
     public constructor Z2()
     private final val privateProperty: kotlin.Int = 11
     public final val publicProperty: kotlin.Int = 12
@@ -10,7 +10,7 @@ private final class Z2 {
     public final fun publicFun(): kotlin.Unit
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 
-    private final inner class ZInner {
+    internal final inner class ZInner {
         public constructor ZInner()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int

compiler/testData/diagnostics/tests/inline/privateClass.kt

@@ -0,0 +1,25 @@
+// !DIAGNOSTICS: -EXPOSED_PARAMETER_TYPE
+
+private class S public constructor() {
+    fun a() {
+
+    }
+}
+
+internal inline fun x(s: S, z: () -> Unit) {
+    z()
+    <!PRIVATE_CLASS_MEMBER_FROM_INLINE!>S<!>()
+    s.<!PRIVATE_CLASS_MEMBER_FROM_INLINE!>a<!>()
+    test()
+}
+
+private inline fun x2(s: S, z: () -> Unit) {
+    z()
+    S()
+    s.a()
+    test()
+}
+
+private fun test(): S {
+    return S()
+}

compiler/testData/diagnostics/tests/inline/privateClass.txt

@@ -0,0 +1,12 @@
+package
+
+private fun test(): S
+private inline fun x(/*0*/ s: S, /*1*/ z: () -> kotlin.Unit): kotlin.Unit
+
+private final class S {
+    public constructor S()
+    public final fun a(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}