[AA] Allow inner classes in non-static declared member scopes

- An inner class `Inner` in a class `Outer` is accessible as
  `Outer().Inner()` and should thus be part of the non-static declared
  member scope.
- Related issue containing a discussion about inner classes in use-site
  scopes: KT-62023.

^KT-61800

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/components/KtFirScopeProvider.kt

@@ -105,7 +105,7 @@ internal class KtFirScopeProvider(
     ): FirContainingNamesAwareScope {
         val combinedScope = getCombinedFirKotlinDeclaredMemberScope(classSymbol)
         return when (kind) {
-            DeclaredMemberScopeKind.NON_STATIC -> FirNonStaticCallablesOnlyScope(combinedScope)
+            DeclaredMemberScopeKind.NON_STATIC -> FirNonStaticMembersScope(combinedScope)
             DeclaredMemberScopeKind.STATIC -> FirStaticScope(combinedScope)
         }
     }

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/scopes/FirCallableFilteringScope.kt

@@ -13,7 +13,7 @@ import org.jetbrains.kotlin.fir.symbols.impl.FirVariableSymbol
 import org.jetbrains.kotlin.name.Name
 
 /**
- * A base implementation for [FirNonStaticCallablesOnlyScope] and [FirDeclaredMembersOnlyScope], which both filter callables based on some
+ * A base implementation for [FirNonStaticMembersScope] and [FirDeclaredMembersOnlyScope], which both filter callables based on some
  * condition.
  */
 internal abstract class FirCallableFilteringScope(private val baseScope: FirContainingNamesAwareScope) : FirContainingNamesAwareScope() {

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/scopes/FirNonStaticCallablesOnlyScope.kt

@@ -1,32 +0,0 @@
-/*
- * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
- * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
- */
-
-package org.jetbrains.kotlin.analysis.api.fir.scopes
-
-import org.jetbrains.kotlin.fir.declarations.utils.isStatic
-import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutor
-import org.jetbrains.kotlin.fir.scopes.FirContainingNamesAwareScope
-import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
-import org.jetbrains.kotlin.fir.symbols.impl.FirClassifierSymbol
-import org.jetbrains.kotlin.fir.symbols.impl.FirConstructorSymbol
-import org.jetbrains.kotlin.name.Name
-
-/**
- * Excludes static callables and all classifiers.
- */
-internal class FirNonStaticCallablesOnlyScope(
-    private val delegate: FirContainingNamesAwareScope,
-) : FirCallableFilteringScope(delegate) {
-    override fun isTargetCallable(callable: FirCallableSymbol<*>): Boolean = !callable.fir.isStatic
-
-    override fun processDeclaredConstructors(processor: (FirConstructorSymbol) -> Unit) {
-        delegate.processDeclaredConstructors(processor)
-    }
-
-    override fun getClassifierNames(): Set<Name> = emptySet()
-
-    override fun processClassifiersByNameWithSubstitution(name: Name, processor: (FirClassifierSymbol<*>, ConeSubstitutor) -> Unit) {
-    }
-}

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/scopes/FirNonStaticMembersScope.kt

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.analysis.api.fir.scopes
+
+import org.jetbrains.kotlin.fir.declarations.FirMemberDeclaration
+import org.jetbrains.kotlin.fir.declarations.utils.isInner
+import org.jetbrains.kotlin.fir.declarations.utils.isStatic
+import org.jetbrains.kotlin.fir.resolve.substitution.ConeSubstitutor
+import org.jetbrains.kotlin.fir.scopes.FirContainingNamesAwareScope
+import org.jetbrains.kotlin.fir.symbols.impl.FirCallableSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirClassifierSymbol
+import org.jetbrains.kotlin.fir.symbols.impl.FirConstructorSymbol
+import org.jetbrains.kotlin.name.Name
+
+/**
+ * [FirNonStaticMembersScope] includes non-static callables and inner classes.
+ *
+ * Inner classes are included because they are accessible from a value of the outer class. For example:
+ *
+ * ```
+ * class Outer {
+ *     inner class Inner
+ * }
+ *
+ * fun foo() {
+ *     val outer = Outer()
+ *     outer.Inner()
+ * }
+ * ```
+ *
+ * While Kotlin always expects a constructor call when accessing `outer.Inner`, it nonetheless requires inner classes to be contained in
+ * non-static scopes.
+ */
+internal class FirNonStaticMembersScope(
+    private val delegate: FirContainingNamesAwareScope,
+) : FirCallableFilteringScope(delegate) {
+    override fun isTargetCallable(callable: FirCallableSymbol<*>): Boolean = !callable.fir.isStatic
+
+    override fun processDeclaredConstructors(processor: (FirConstructorSymbol) -> Unit) {
+        delegate.processDeclaredConstructors(processor)
+    }
+
+    override fun getClassifierNames(): Set<Name> = delegate.getClassifierNames()
+
+    override fun processClassifiersByNameWithSubstitution(name: Name, processor: (FirClassifierSymbol<*>, ConeSubstitutor) -> Unit) {
+        processInnerClassesByName(name, processor)
+    }
+
+    private fun processInnerClassesByName(name: Name, processor: (FirClassifierSymbol<*>, ConeSubstitutor) -> Unit) {
+        delegate.processClassifiersByNameWithSubstitution(name) { classifier, substitutor ->
+            val firDeclaration = classifier.fir
+            if (firDeclaration is FirMemberDeclaration && firDeclaration.isInner) {
+                processor(classifier, substitutor)
+            }
+        }
+    }
+}