FIR LC: populate DefaultImpls if an interface has default implementations

analysis/analysis-api-fe10/src/org/jetbrains/kotlin/analysis/api/descriptors/KtFe10AnalysisSession.kt

@@ -47,4 +47,4 @@ class KtFe10AnalysisSession(val analysisContext: Fe10AnalysisContext) : KtAnalys
     override fun createContextDependentCopy(originalKtFile: KtFile, elementToReanalyze: KtElement): KtAnalysisSession {
         return KtFe10AnalysisSession(elementToReanalyze, token)
     }
-}
+}

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/KtFirAnalysisSession.kt

@@ -6,10 +6,8 @@
 package org.jetbrains.kotlin.analysis.api.fir
 
 import com.intellij.openapi.project.Project
-import com.intellij.psi.search.GlobalSearchScope
 import org.jetbrains.kotlin.analysis.api.InvalidWayOfUsingAnalysisSession
 import org.jetbrains.kotlin.analysis.api.KtAnalysisSession
-import org.jetbrains.kotlin.analysis.api.assertIsValidAndAccessible
 import org.jetbrains.kotlin.analysis.api.components.*
 import org.jetbrains.kotlin.analysis.api.fir.components.*
 import org.jetbrains.kotlin.analysis.api.fir.symbols.KtFirOverrideInfoProvider

analysis/symbol-light-classes/src/org/jetbrains/kotlin/light/classes/symbol/classes/FirLightAnonymousClassForSymbol.kt

@@ -88,7 +88,7 @@ internal class FirLightAnonymousClassForSymbol(
     }
 
     private val _ownInnerClasses: List<FirLightClassBase> by lazyPub {
-        anonymousObjectSymbol.createInnerClasses(manager)
+        anonymousObjectSymbol.createInnerClasses(manager, this, kotlinOrigin)
     }
 
     override fun getOwnInnerClasses(): List<PsiClass> = _ownInnerClasses

analysis/symbol-light-classes/src/org/jetbrains/kotlin/light/classes/symbol/classes/FirLightClassForClassOrObjectSymbol.kt

@@ -79,7 +79,7 @@ internal abstract class FirLightClassForClassOrObjectSymbol(
         _typeParameterList?.typeParameters ?: PsiTypeParameter.EMPTY_ARRAY
 
     private val _ownInnerClasses: List<FirLightClassBase> by lazyPub {
-        classOrObjectSymbol.createInnerClasses(manager)
+        classOrObjectSymbol.createInnerClasses(manager, this, kotlinOrigin)
     }
 
     override fun getOwnInnerClasses(): List<PsiClass> = _ownInnerClasses

analysis/symbol-light-classes/src/org/jetbrains/kotlin/light/classes/symbol/classes/FirLightClassForInterfaceDefaultImpls.kt

@@ -0,0 +1,52 @@
+/*
+ * Copyright 2010-2021 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.light.classes.symbol
+
+import com.intellij.psi.*
+import com.intellij.util.IncorrectOperationException
+import org.jetbrains.kotlin.analysis.api.symbols.KtNamedClassOrObjectSymbol
+import org.jetbrains.kotlin.asJava.classes.lazyPub
+import org.jetbrains.kotlin.load.java.JvmAbi
+
+internal class FirLightClassForInterfaceDefaultImpls(
+    private val classOrObjectSymbol: KtNamedClassOrObjectSymbol,
+    private val containingClass: FirLightClassBase,
+    manager: PsiManager
+) : FirLightInterfaceClassSymbol(classOrObjectSymbol, manager) {
+    override fun getQualifiedName(): String? = containingClass.qualifiedName?.let { it + ".${JvmAbi.DEFAULT_IMPLS_CLASS_NAME}" }
+
+    override fun getName() = JvmAbi.DEFAULT_IMPLS_CLASS_NAME
+    override fun getParent() = containingClass
+
+    override fun copy() =
+        FirLightClassForInterfaceDefaultImpls(classOrObjectSymbol, containingClass, manager)
+
+    override fun getTypeParameterList(): PsiTypeParameterList? = null
+    override fun getTypeParameters(): Array<PsiTypeParameter> = emptyArray()
+
+    private val _modifierList: PsiModifierList? by lazyPub {
+        val modifiers = setOf(PsiModifier.PUBLIC, PsiModifier.STATIC, PsiModifier.FINAL)
+        FirLightClassModifierList(this@FirLightClassForInterfaceDefaultImpls, modifiers, emptyList())
+    }
+
+    override fun getModifierList(): PsiModifierList? = _modifierList
+
+    override fun isInterface(): Boolean = false
+    override fun isDeprecated(): Boolean = false
+    override fun isAnnotationType(): Boolean = false
+    override fun isEnum(): Boolean = false
+    override fun hasTypeParameters(): Boolean = false
+    override fun isInheritor(baseClass: PsiClass, checkDeep: Boolean): Boolean = false
+
+    @Throws(IncorrectOperationException::class)
+    override fun setName(name: String): PsiElement {
+        throw IncorrectOperationException("Impossible to rename DefaultImpls")
+    }
+
+    override fun getContainingClass() = containingClass
+
+    override fun getOwnInnerClasses() = emptyList<PsiClass>()
+}

analysis/symbol-light-classes/src/org/jetbrains/kotlin/light/classes/symbol/classes/FirLightInterfaceClassSymbol.kt

@@ -19,7 +19,7 @@ import org.jetbrains.kotlin.analysis.api.symbols.markers.isPrivateOrPrivateToThi
 import org.jetbrains.kotlin.light.classes.symbol.classes.createInheritanceList
 import org.jetbrains.kotlin.light.classes.symbol.classes.createMethods
 
-internal class FirLightInterfaceClassSymbol(
+internal open class FirLightInterfaceClassSymbol(
     private val classOrObjectSymbol: KtNamedClassOrObjectSymbol,
     manager: PsiManager
 ) : FirLightInterfaceOrAnnotationClassSymbol(classOrObjectSymbol, manager) {

analysis/symbol-light-classes/src/org/jetbrains/kotlin/light/classes/symbol/classes/firLightClassUtils.kt

@@ -18,10 +18,15 @@ import org.jetbrains.kotlin.analysis.api.tokens.HackToForceAllowRunningAnalyzeOn
 import org.jetbrains.kotlin.analysis.api.tokens.hackyAllowRunningOnEdt
 import org.jetbrains.kotlin.analysis.api.types.KtNonErrorClassType
 import org.jetbrains.kotlin.analysis.api.types.KtType
+import org.jetbrains.kotlin.analysis.project.structure.KtSourceModule
+import org.jetbrains.kotlin.analysis.project.structure.getKtModuleOfTypeSafe
 import org.jetbrains.kotlin.asJava.builder.LightMemberOriginForDeclaration
 import org.jetbrains.kotlin.asJava.classes.*
 import org.jetbrains.kotlin.asJava.elements.KtLightField
 import org.jetbrains.kotlin.asJava.elements.KtLightMethod
+import org.jetbrains.kotlin.asJava.hasInterfaceDefaultImpls
+import org.jetbrains.kotlin.config.JvmAnalysisFlags
+import org.jetbrains.kotlin.config.JvmDefaultMode
 import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.annotations.AnnotationUseSiteTarget
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -394,7 +399,11 @@ internal fun FirLightClassBase.createInheritanceList(forExtendsList: Boolean, su
     return listBuilder
 }
 
-internal fun KtSymbolWithMembers.createInnerClasses(manager: PsiManager): List<FirLightClassBase> {
+internal fun KtSymbolWithMembers.createInnerClasses(
+    manager: PsiManager,
+    containingClass: FirLightClassBase,
+    classOrObject: KtClassOrObject?
+): List<FirLightClassBase> {
     val result = ArrayList<FirLightClassBase>()
 
     // workaround for ClassInnerStuffCache not supporting classes with null names, see KT-13927
@@ -407,10 +416,16 @@ internal fun KtSymbolWithMembers.createInnerClasses(manager: PsiManager): List<F
         }
     }
 
-    //TODO
-    //if (classOrObject.hasInterfaceDefaultImpls) {
-    //    result.add(KtLightClassForInterfaceDefaultImpls(classOrObject))
-    //}
+    val jvmDefaultMode =
+        classOrObject?.getKtModuleOfTypeSafe<KtSourceModule>()?.languageVersionSettings?.getFlag(JvmAnalysisFlags.jvmDefaultMode)
+            ?: JvmDefaultMode.DEFAULT
+
+    if (this is KtNamedClassOrObjectSymbol &&
+        classOrObject?.hasInterfaceDefaultImpls == true &&
+        jvmDefaultMode != JvmDefaultMode.ALL_INCOMPATIBLE
+    ) {
+        result.add(FirLightClassForInterfaceDefaultImpls(this, containingClass, manager))
+    }
     return result
 }
 

compiler/testData/asJava/ultraLightClasses/defaultMethodInKotlinWithSettingAllCompatibility.kt

@@ -7,4 +7,6 @@ interface KtInterface {
     }
 
     fun withoutBody()
-}
+}
+
+// FIR_COMPARISON