[FIR] Disallow qualified access to uninitialized fields in delegate

When using a field as the delegate for a super-interface of an object,
make sure uninitialized fields are not allowed. Specifically, disallow
access to these fields when referenced via object qualifier.

^KT-56489 Fixed

compiler/fir/checkers/src/org/jetbrains/kotlin/fir/analysis/cfa/FirPropertyInitializationAnalyzer.kt

@@ -96,8 +96,11 @@ private fun PropertyInitializationInfoData.checkPropertyAccesses(
     doNotReportConstantUninitialized: Boolean,
     scopes: MutableMap<FirPropertySymbol, FirDeclaration?>,
 ) {
-    fun FirQualifiedAccessExpression.hasCorrectReceiver() =
+    fun FirQualifiedAccessExpression.hasMatchingReceiver(): Boolean {
-        (dispatchReceiver?.unwrapSmartcastExpression() as? FirThisReceiverExpression)?.calleeReference?.boundSymbol == receiver
+        val expression = dispatchReceiver?.unwrapSmartcastExpression()
+        return (expression as? FirThisReceiverExpression)?.calleeReference?.boundSymbol == receiver ||
+                (expression as? FirResolvedQualifier)?.symbol == receiver
+    }
 
     for (node in graph.nodes) {
         when {
@@ -115,7 +118,7 @@ private fun PropertyInitializationInfoData.checkPropertyAccesses(
 
             node is VariableAssignmentNode -> {
                 val symbol = node.fir.calleeReference?.toResolvedPropertySymbol() ?: continue
-                if (!symbol.isVal || node.fir.unwrapLValue()?.hasCorrectReceiver() != true || symbol !in properties) continue
+                if (!symbol.isVal || node.fir.unwrapLValue()?.hasMatchingReceiver() != true || symbol !in properties) continue
 
                 if (getValue(node).values.any { it[symbol]?.canBeRevisited() == true }) {
                     reporter.reportOn(node.fir.lValue.source, FirErrors.VAL_REASSIGNMENT, symbol, context)
@@ -133,7 +136,7 @@ private fun PropertyInitializationInfoData.checkPropertyAccesses(
                 if (node.fir.resolvedType.hasDiagnosticKind(DiagnosticKind.RecursionInImplicitTypes)) continue
                 val symbol = node.fir.calleeReference.toResolvedPropertySymbol() ?: continue
                 if (doNotReportConstantUninitialized && symbol.isConst) continue
-                if (!symbol.isLateInit && !symbol.isExternal && node.fir.hasCorrectReceiver() && symbol in properties &&
+                if (!symbol.isLateInit && !symbol.isExternal && node.fir.hasMatchingReceiver() && symbol in properties &&
                     getValue(node).values.any { it[symbol]?.isDefinitelyVisited() != true }
                 ) {
                     reporter.reportOn(node.fir.source, FirErrors.UNINITIALIZED_VARIABLE, symbol, context)

compiler/testData/diagnostics/tests/controlFlowAnalysis/fieldAsClassDelegate.fir.kt

@@ -1,5 +1,6 @@
-// See KT-15566
+// WITH_STDLIB
 // NI_EXPECTED_FILE
+// ISSUE: KT-15566, KT-56489
 
 import DefaultHttpClient.client
 
@@ -9,7 +10,7 @@ class HttpClientImpl : HttpClient
 
 // Below we should have initialization error for both (!) delegates
 
-object DefaultHttpClient : HttpClient by client {
+object DefaultHttpClient : HttpClient by <!UNINITIALIZED_VARIABLE!>client<!> {
     val client = HttpClientImpl()
 }
 
@@ -22,15 +23,10 @@ object DefaultHttpClientWithFun : HttpClient by fClient() {
 
 private fun fClient() = HttpClientImpl()
 
-private fun <T> lazy(init: () -> T): kotlin.<!UNRESOLVED_REFERENCE!>Lazy<!><T> {
-    init()
-    null!!
-}
-
 object DefaultHttpClientWithBy : HttpClient by client {
     val client by lazy { HttpClientImpl() }
 }
 
-object DefaultFqHttpClient : HttpClient by DefaultFqHttpClient.client {
+object DefaultFqHttpClient : HttpClient by <!UNINITIALIZED_VARIABLE!>DefaultFqHttpClient.client<!> {
     val client = HttpClientImpl()
 }

compiler/testData/diagnostics/tests/controlFlowAnalysis/fieldAsClassDelegate.kt

@@ -1,5 +1,6 @@
-// See KT-15566
+// WITH_STDLIB
 // NI_EXPECTED_FILE
+// ISSUE: KT-15566, KT-56489
 
 import DefaultHttpClient.client
 
@@ -22,15 +23,10 @@ object DefaultHttpClientWithFun : HttpClient by fClient() {
 
 private fun fClient() = HttpClientImpl()
 
-private fun <T> lazy(init: () -> T): kotlin.<!UNRESOLVED_REFERENCE!>Lazy<!><T> {
-    init()
-    null!!
-}
-
 object DefaultHttpClientWithBy : HttpClient by client {
     val client by lazy { HttpClientImpl() }
 }
 
 object DefaultFqHttpClient : HttpClient by DefaultFqHttpClient.<!UNINITIALIZED_VARIABLE!>client<!> {
     val client = HttpClientImpl()
-}
+}

compiler/testData/diagnostics/tests/controlFlowAnalysis/fieldAsClassDelegate.ni.txt

@@ -1,7 +1,6 @@
 package
 
 private fun fClient(): HttpClientImpl
-private fun </*0*/ T> lazy(/*0*/ init: () -> T): [Error type: Unresolved type for kotlin.Lazy<T>]<T>
 
 public object DefaultFqHttpClient : HttpClient {
     private constructor DefaultFqHttpClient()
@@ -21,7 +20,7 @@ public object DefaultHttpClient : HttpClient {
 
 public object DefaultHttpClientWithBy : HttpClient {
     private constructor DefaultHttpClientWithBy()
-    public final val client: [Error type: Error delegation type for lazy { HttpClientImpl() }]
+    public final val client: HttpClientImpl
     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