Fir2Ir: use lazy declarations for imported toplevel functions and properties

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrDeclarationStorage.kt

@@ -715,7 +715,7 @@ class Fir2IrDeclarationStorage(
                 if (irParent != null) {
                     parent = irParent
                 }
-                if (correspondingProperty is Fir2IrLazyProperty && !isFakeOverride && thisReceiverOwner != null) {
+                if (correspondingProperty is Fir2IrLazyProperty && correspondingProperty.containingClass != null && !isFakeOverride && thisReceiverOwner != null) {
                     this.overriddenSymbols = correspondingProperty.fir.generateOverriddenAccessorSymbols(
                         correspondingProperty.containingClass, !isSetter, session, scopeSession, declarationStorage, fakeOverrideGenerator
                     )
@@ -1264,12 +1264,13 @@ class Fir2IrDeclarationStorage(
         val firFunctionSymbol = fir.symbol
         val irFunction = fir.convertWithOffsets { startOffset, endOffset ->
             symbolTable.declareSimpleFunction(signature, { symbol }) {
-                val isFakeOverride = fir.isSubstitutionOrIntersectionOverride &&
+                val isFakeOverride = firFunctionSymbol is FirNamedFunctionSymbol &&
+                        fir.isSubstitutionOrIntersectionOverride &&
                         firFunctionSymbol.dispatchReceiverClassOrNull() !=
                         firFunctionSymbol.originalForSubstitutionOverride?.dispatchReceiverClassOrNull()
                 Fir2IrLazySimpleFunction(
                     components, startOffset, endOffset, declarationOrigin,
-                    fir, lazyParent.fir, symbol, isFakeOverride
+                    fir, (lazyParent as? Fir2IrLazyClass)?.fir, symbol, isFakeOverride
                 ).apply {
                     this.parent = lazyParent
                 }
@@ -1347,7 +1348,7 @@ class Fir2IrDeclarationStorage(
                             firPropertySymbol.dispatchReceiverClassOrNull() !=
                             firPropertySymbol.originalForSubstitutionOverride?.dispatchReceiverClassOrNull()
                 Fir2IrLazyProperty(
-                    components, startOffset, endOffset, declarationOrigin, fir, lazyParent.fir, symbol, isFakeOverride
+                    components, startOffset, endOffset, declarationOrigin, fir, (lazyParent as? Fir2IrLazyClass)?.fir, symbol, isFakeOverride
                 ).apply {
                     this.parent = lazyParent
                 }
@@ -1388,7 +1389,7 @@ class Fir2IrDeclarationStorage(
         dispatchReceiverLookupTag: ConeClassLikeLookupTag?,
         getCachedIrDeclaration: (firDeclaration: F, dispatchReceiverLookupTag: ConeClassLikeLookupTag?, () -> IdSignature?) -> I?,
         createIrDeclaration: (parent: IrDeclarationParent?, origin: IrDeclarationOrigin) -> I,
-        createIrLazyDeclaration: (signature: IdSignature, lazyOwner: Fir2IrLazyClass, origin: IrDeclarationOrigin) -> I,
+        createIrLazyDeclaration: (signature: IdSignature, lazyOwner: IrDeclarationParent, origin: IrDeclarationOrigin) -> I,
     ): IrSymbol {
         val fir = firSymbol.fir as F
         val irParent by lazy { findIrParent(fir) }
@@ -1424,6 +1425,11 @@ class Fir2IrDeclarationStorage(
                         }
                     }
                 }
+                is IrExternalPackageFragment -> {
+                    signature?.let {
+                        return createIrLazyDeclaration(it, parent, declarationOrigin).symbol
+                    }
+                }
             }
             return createIrDeclaration(irParent, declarationOrigin).apply {
                 (this as IrDeclaration).setAndModifyParent(irParent)

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/AbstractFir2IrLazyFunction.kt

@@ -24,6 +24,7 @@ import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.util.DeclarationStubGenerator
 import org.jetbrains.kotlin.ir.util.TypeTranslator
+import org.jetbrains.kotlin.ir.util.isFacadeClass
 import org.jetbrains.kotlin.ir.util.isObject
 import org.jetbrains.kotlin.name.ClassId
 import org.jetbrains.kotlin.resolve.annotations.JVM_STATIC_ANNOTATION_FQ_NAME
@@ -89,7 +90,7 @@ abstract class AbstractFir2IrLazyFunction<F : FirCallableDeclaration>(
         containingClass: IrClass,
         staticOwner: FirCallableDeclaration
     ): Boolean {
-        return !staticOwner.isStatic &&
+        return !staticOwner.isStatic && !containingClass.isFacadeClass &&
                 (!containingClass.isObject || containingClass.isCompanion || !staticOwner.hasAnnotation(JVM_STATIC_CLASS_ID))
     }
 

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyProperty.kt

@@ -39,7 +39,7 @@ class Fir2IrLazyProperty(
     override val endOffset: Int,
     override var origin: IrDeclarationOrigin,
     override val fir: FirProperty,
-    internal val containingClass: FirRegularClass,
+    internal val containingClass: FirRegularClass?,
     override val symbol: Fir2IrPropertySymbol,
     override val isFakeOverride: Boolean
 ) : IrProperty(), AbstractFir2IrLazyDeclaration<FirProperty, IrProperty>, Fir2IrComponents by components {
@@ -171,7 +171,7 @@ class Fir2IrLazyProperty(
             },
             fir.getter, isSetter = false, fir, containingClass,
             Fir2IrSimpleFunctionSymbol(
-                signatureComposer.composeAccessorSignature(fir, isSetter = false, containingClass.symbol.toLookupTag())!!
+                signatureComposer.composeAccessorSignature(fir, isSetter = false, containingClass?.symbol?.toLookupTag())!!
             ),
             isFakeOverride
         ).apply {
@@ -199,7 +199,7 @@ class Fir2IrLazyProperty(
             },
             fir.setter, isSetter = true, fir, containingClass,
             Fir2IrSimpleFunctionSymbol(
-                signatureComposer.composeAccessorSignature(fir, isSetter = true, containingClass.symbol.toLookupTag())!!
+                signatureComposer.composeAccessorSignature(fir, isSetter = true, containingClass?.symbol?.toLookupTag())!!
             ),
             isFakeOverride
         ).apply {
@@ -217,6 +217,7 @@ class Fir2IrLazyProperty(
     }
 
     override var overriddenSymbols: List<IrPropertySymbol> by lazyVar(lock) {
+        if (containingClass == null) return@lazyVar emptyList()
         fir.generateOverriddenPropertySymbols(
             containingClass,
             session,

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazyPropertyAccessor.kt

@@ -21,6 +21,7 @@ import org.jetbrains.kotlin.ir.declarations.lazy.lazyVar
 import org.jetbrains.kotlin.ir.expressions.IrConstructorCall
 import org.jetbrains.kotlin.ir.symbols.IrSimpleFunctionSymbol
 import org.jetbrains.kotlin.ir.types.IrType
+import org.jetbrains.kotlin.ir.util.isFacadeClass
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedContainerSource
 
@@ -32,7 +33,7 @@ class Fir2IrLazyPropertyAccessor(
     private val firAccessor: FirPropertyAccessor?,
     private val isSetter: Boolean,
     private val firParentProperty: FirProperty,
-    firParentClass: FirRegularClass,
+    firParentClass: FirRegularClass?,
     symbol: Fir2IrSimpleFunctionSymbol,
     isFakeOverride: Boolean
 ) : AbstractFir2IrLazyFunction<FirCallableDeclaration>(components, startOffset, endOffset, origin, symbol, isFakeOverride) {
@@ -60,7 +61,7 @@ class Fir2IrLazyPropertyAccessor(
     }
 
     override var dispatchReceiverParameter: IrValueParameter? by lazyVar(lock) {
-        val containingClass = parent as? IrClass
+        val containingClass = (parent as? IrClass)?.takeUnless { it.isFacadeClass }
         if (containingClass != null && shouldHaveDispatchReceiver(containingClass, firParentProperty)
         ) {
             createThisReceiverParameter(thisType = containingClass.thisReceiver?.type ?: error("No this receiver for containing class"))
@@ -105,6 +106,7 @@ class Fir2IrLazyPropertyAccessor(
     }
 
     override var overriddenSymbols: List<IrSimpleFunctionSymbol> by lazyVar(lock) {
+        if (firParentClass == null) return@lazyVar emptyList()
         firParentProperty.generateOverriddenAccessorSymbols(
             firParentClass,
             !isSetter,

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/lazy/Fir2IrLazySimpleFunction.kt

@@ -31,7 +31,7 @@ class Fir2IrLazySimpleFunction(
     endOffset: Int,
     origin: IrDeclarationOrigin,
     override val fir: FirSimpleFunction,
-    firParent: FirRegularClass,
+    firParent: FirRegularClass?,
     symbol: Fir2IrSimpleFunctionSymbol,
     isFakeOverride: Boolean
 ) : AbstractFir2IrLazyFunction<FirSimpleFunction>(components, startOffset, endOffset, origin, symbol, isFakeOverride) {
@@ -90,6 +90,7 @@ class Fir2IrLazySimpleFunction(
     }
 
     override var overriddenSymbols: List<IrSimpleFunctionSymbol> by lazyVar(lock) {
+        if (firParent == null) return@lazyVar emptyList()
         val parent = parent
         if (isFakeOverride && parent is Fir2IrLazyClass) {
             fakeOverrideGenerator.calcBaseSymbolsForFakeOverrideFunction(