FIR: Make qualifier have only one static scope

It's more correct as that's how it works in FE 1.0

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/QualifierReceiver.kt

@@ -6,24 +6,20 @@
 package org.jetbrains.kotlin.fir.resolve.calls
 
 import org.jetbrains.kotlin.fir.FirSession
-import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.declarations.FirClassLikeDeclaration
+import org.jetbrains.kotlin.fir.declarations.FirRegularClass
+import org.jetbrains.kotlin.fir.declarations.FirTypeAlias
+import org.jetbrains.kotlin.fir.declarations.expandedConeType
 import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.FirResolvedQualifier
 import org.jetbrains.kotlin.fir.resolve.ScopeSession
-import org.jetbrains.kotlin.fir.resolve.ScopeSessionKey
-import org.jetbrains.kotlin.fir.resolve.lookupSuperTypes
 import org.jetbrains.kotlin.fir.resolve.toSymbol
 import org.jetbrains.kotlin.fir.scopes.FirScope
-import org.jetbrains.kotlin.fir.scopes.KotlinScopeProvider
-import org.jetbrains.kotlin.fir.scopes.impl.FirCompositeScope
 import org.jetbrains.kotlin.fir.scopes.impl.FirOnlyCallablesScope
 import org.jetbrains.kotlin.fir.scopes.impl.FirOnlyClassifiersScope
 import org.jetbrains.kotlin.fir.scopes.impl.FirPackageMemberScope
 import org.jetbrains.kotlin.fir.symbols.impl.FirClassLikeSymbol
 import org.jetbrains.kotlin.fir.symbols.impl.FirRegularClassSymbol
-import org.jetbrains.kotlin.fir.types.ConeClassErrorType
-import org.jetbrains.kotlin.fir.types.ConeClassLikeType
-import java.util.*
 
 
 fun FirClassLikeDeclaration<*>.fullyExpandedClass(useSiteSession: FirSession): FirRegularClass? {
@@ -53,7 +49,7 @@ fun createQualifierReceiver(
 abstract class QualifierReceiver(final override val explicitReceiver: FirExpression) : AbstractExplicitReceiver<FirResolvedQualifier>() {
 
     abstract fun classifierScope(): FirScope?
-    abstract fun callableScopes(): List<FirScope>
+    abstract fun callableScope(): FirScope?
 }
 
 class ClassQualifierReceiver(
@@ -64,71 +60,10 @@ class ClassQualifierReceiver(
     val scopeSession: ScopeSession
 ) : QualifierReceiver(explicitReceiver) {
 
-    private companion object {
-        val SUPERTYPE_STATICS_SCOPE_SESSION_KEY = object : ScopeSessionKey<FirClass<*>, List<FirScope>>() {}
-    }
-
-    private fun collectSuperTypeScopesComposedByDepth(
-        klass: FirClass<*>,
-        useSiteSession: FirSession,
-        scopeSession: ScopeSession,
-    ): List<FirScope> {
-        val result = mutableListOf<FirScope>()
-        val provider = klass.scopeProvider
-        val levelScopes = mutableListOf<FirScope>()
-        var currentDepth = 1
-        val queue =
-            ArrayDeque<Pair<ConeClassLikeType, Int>>()
-        queue.addAll(
-            lookupSuperTypes(klass, lookupInterfaces = true, deep = false, useSiteSession = useSiteSession).map { it to 1 },
-        )
-        val visitedSymbols = mutableSetOf<FirRegularClassSymbol>()
-        while (queue.isNotEmpty()) {
-            val (useSiteSuperType, depth) = queue.poll()
-            if (depth > currentDepth) {
-                currentDepth = depth
-                result += FirCompositeScope(levelScopes.toMutableList())
-                levelScopes.clear()
-            }
-            if (useSiteSuperType is ConeClassErrorType) continue
-            val superTypeSymbol = useSiteSuperType.lookupTag.toSymbol(useSiteSession) as? FirRegularClassSymbol
-                ?: continue
-            if (!visitedSymbols.add(superTypeSymbol)) continue
-            val superTypeScope = provider.getStaticMemberScopeForCallables(
-                superTypeSymbol.fir, useSiteSession, scopeSession,
-            )
-            if (superTypeScope != null) {
-                levelScopes += superTypeScope
-            }
-            queue.addAll(
-                lookupSuperTypes(
-                    superTypeSymbol.fir, lookupInterfaces = true, deep = false, useSiteSession = useSiteSession,
-                ).map { it to currentDepth + 1 },
-            )
-        }
-        return result
-    }
-
-    private fun getCallableScopes(
-        useSiteSession: FirSession,
-        scopeSession: ScopeSession,
-    ): List<FirScope> {
+    override fun callableScope(): FirScope? {
         val klass = classSymbol.fir
-        val result = mutableListOf<FirScope>()
         val provider = klass.scopeProvider
-        val klassScope = provider.getStaticMemberScopeForCallables(klass, useSiteSession, scopeSession)
-        if (klassScope != null) {
-            result += klassScope
-            if (provider is KotlinScopeProvider) return result
-            result += scopeSession.getOrBuild(klass, SUPERTYPE_STATICS_SCOPE_SESSION_KEY) {
-                collectSuperTypeScopesComposedByDepth(klass, useSiteSession, scopeSession)
-            }
-        }
-        return result
-    }
-
-    override fun callableScopes(): List<FirScope> {
-        return getCallableScopes(useSiteSession, scopeSession)
+        return provider.getStaticMemberScopeForCallables(klass, useSiteSession, scopeSession)
     }
 
     override fun classifierScope(): FirScope? {
@@ -148,7 +83,5 @@ class PackageQualifierReceiver(
         return FirOnlyClassifiersScope(scope)
     }
 
-    override fun callableScopes(): List<FirScope> {
-        return listOf(FirOnlyCallablesScope(scope))
-    }
+    override fun callableScope() = FirOnlyCallablesScope(scope)
 }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/FirTowerResolverSession.kt

@@ -155,13 +155,12 @@ class FirTowerResolverSession internal constructor(
         info: CallInfo, qualifierReceiver: QualifierReceiver?
     ) {
         if (qualifierReceiver == null) return
-        for ((depth, qualifierScope) in qualifierReceiver.callableScopes().withIndex()) {
-            processLevel(
-                qualifierScope.toScopeTowerLevel(includeInnerConstructors = false),
-                info.noStubReceiver(), TowerGroup.Qualifier(depth),
-                useParentGroupForInvokes = true,
-            )
-        }
+        val callableScope = qualifierReceiver.callableScope() ?: return
+        processLevel(
+            callableScope.toScopeTowerLevel(includeInnerConstructors = false),
+            info.noStubReceiver(), TowerGroup.Qualifier,
+            useParentGroupForInvokes = true,
+        )
     }
 
     private suspend fun processClassifierScope(

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/tower/TowerGroup.kt

@@ -12,7 +12,7 @@ sealed class TowerGroupKind(private val index: Int) : Comparable<TowerGroupKind>
 
     object ClassifierPrioritized : TowerGroupKind(-10)
 
-    class Qualifier(depth: Int) : WithDepth(0, depth)
+    object Qualifier : TowerGroupKind(0)
 
     object Classifier : TowerGroupKind(10)
 
@@ -59,7 +59,7 @@ private constructor(
 
         val ClassifierPrioritized = kindOf(TowerGroupKind.ClassifierPrioritized)
 
-        fun Qualifier(depth: Int) = kindOf(TowerGroupKind.Qualifier(depth))
+        val Qualifier = kindOf(TowerGroupKind.Qualifier)
 
         val Classifier = kindOf(TowerGroupKind.Classifier)