[AA] Consider context receivers in FirTowerDataElement.getAvailableScope

compiler/fir/providers/src/org/jetbrains/kotlin/fir/resolve/calls/FirReceivers.kt

@@ -17,6 +17,7 @@ import org.jetbrains.kotlin.fir.expressions.builder.buildThisReceiverExpression
 import org.jetbrains.kotlin.fir.references.builder.buildImplicitThisReference
 import org.jetbrains.kotlin.fir.renderWithType
 import org.jetbrains.kotlin.fir.resolve.ScopeSession
+import org.jetbrains.kotlin.fir.resolve.fullyExpandedType
 import org.jetbrains.kotlin.fir.resolve.scope
 import org.jetbrains.kotlin.fir.resolve.smartcastScope
 import org.jetbrains.kotlin.fir.scopes.FakeOverrideTypeCalculator
@@ -29,6 +30,7 @@ import org.jetbrains.kotlin.fir.types.*
 import org.jetbrains.kotlin.fir.types.builder.buildResolvedTypeRef
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.types.SmartcastStability
+import org.jetbrains.kotlin.utils.addToStdlib.applyIf
 
 interface Receiver
 
@@ -88,6 +90,8 @@ sealed class ImplicitReceiverValue<S : FirBasedSymbol<*>>(
 
     val originalType: ConeKotlinType = type
 
+    val expandedType: ConeKotlinType = type.applyIf(type is ConeClassLikeType) { fullyExpandedType(useSiteSession) }
+
     var implicitScope: FirTypeScope? =
         type.scope(useSiteSession, scopeSession, FakeOverrideTypeCalculator.DoNothing, requiredPhase = FirResolvePhase.STATUS)
         private set

compiler/fir/semantics/src/org/jetbrains/kotlin/fir/declarations/ImplicitReceiverUtils.kt

@@ -14,10 +14,13 @@ import org.jetbrains.kotlin.fir.resolve.*
 import org.jetbrains.kotlin.fir.resolve.calls.*
 import org.jetbrains.kotlin.fir.scopes.FirContainingNamesAwareScope
 import org.jetbrains.kotlin.fir.scopes.FirScope
+import org.jetbrains.kotlin.fir.scopes.FirTypeScope
 import org.jetbrains.kotlin.fir.scopes.impl.FirLocalScope
 import org.jetbrains.kotlin.fir.scopes.impl.wrapNestedClassifierScopeWithSubstitutionForSuperType
 import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
+import org.jetbrains.kotlin.fir.types.ConeErrorType
 import org.jetbrains.kotlin.fir.types.ConeKotlinType
+import org.jetbrains.kotlin.fir.types.ConeStubType
 import org.jetbrains.kotlin.fir.types.coneType
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.utils.addIfNotNull
@@ -219,6 +222,7 @@ class FirTowerDataContext private constructor(
     }
 }
 
+// Each FirTowerDataElement has exactly one non-null value among values of properties: scope, implicitReceiver and contextReceiverGroup.
 class FirTowerDataElement(
     val scope: FirScope?,
     val implicitReceiver: ImplicitReceiverValue<*>?,
@@ -236,11 +240,24 @@ class FirTowerDataElement(
         )
 
     /**
-     * Returns [scope] if it is not null. Otherwise, returns [implicitReceiver.implicitScope].
+     * Returns [scope] if it is not null. Otherwise, returns scopes of implicit receivers (including context receivers).
      *
      * Note that a scope for a companion object is an implicit scope.
      */
-    fun getAvailableScope() = scope ?: implicitReceiver?.implicitScope
+    fun getAvailableScopes(): List<FirScope> = when {
+        scope != null -> listOf(scope)
+        implicitReceiver != null -> listOf(implicitReceiver.getImplicitScope())
+        contextReceiverGroup != null -> contextReceiverGroup.map { it.getImplicitScope() }
+        else -> error("Tower data element is expected to have either scope or implicit receivers.")
+    }
+
+    private fun ImplicitReceiverValue<*>.getImplicitScope(): FirScope {
+        return when (expandedType) {
+            is ConeErrorType,
+            is ConeStubType -> FirTypeScope.Empty
+            else -> implicitScope ?: error("Scope for type ${type::class.simpleName} is null.")
+        }
+    }
 }
 
 fun ImplicitReceiverValue<*>.asTowerDataElement(): FirTowerDataElement =