From 7dea06d2a75be3a63aeaf953241f8ec1c567a244 Mon Sep 17 00:00:00 2001
From: Mikhail Glukhikh <mikhail.glukhikh@jetbrains.com>
Date: Mon, 18 Nov 2019 13:53:36 +0300
Subject: [PATCH] FIR tower resolve: make companion members accessible from
 derived classes

---
 .../kotlin/fir/resolve/calls/FirReceivers.kt    | 10 ++++++++--
 .../fir/resolve/calls/FirTowerResolver.kt       |  8 ++++----
 .../resolve/expresssions/protectedVisibility.kt | 11 ++++++++++-
 .../expresssions/protectedVisibility.txt        | 17 ++++++++++++++++-
 4 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/FirReceivers.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/FirReceivers.kt
index 65c59300a03..7a541c6dcf6 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/FirReceivers.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/FirReceivers.kt
@@ -89,8 +89,14 @@ class ImplicitDispatchReceiverValue(
     useSiteSession: FirSession,
     scopeSession: ScopeSession
 ) : ImplicitReceiverValue<FirClassSymbol<*>>(boundSymbol, type, useSiteSession, scopeSession) {
-    val implicitCompanionScope: FirScope? =
-        (boundSymbol.fir as? FirRegularClass)?.companionObject?.buildUseSiteMemberScope(useSiteSession, scopeSession)
+    val implicitCompanionScopes: List<FirScope> = run {
+        val klass = boundSymbol.fir as? FirRegularClass ?: return@run emptyList()
+        listOfNotNull(klass.companionObject?.buildUseSiteMemberScope(useSiteSession, scopeSession)) +
+                lookupSuperTypes(klass, lookupInterfaces = false, deep = true, useSiteSession = useSiteSession).mapNotNull {
+                    val superClass = (it as? ConeClassType)?.lookupTag?.toSymbol(useSiteSession)?.fir as? FirRegularClass
+                    superClass?.companionObject?.buildUseSiteMemberScope(useSiteSession, scopeSession)
+                }
+    }
 }
 
 class ImplicitExtensionReceiverValue(
diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/FirTowerResolver.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/FirTowerResolver.kt
index 0485175adf0..ac7db163a2a 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/FirTowerResolver.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/calls/FirTowerResolver.kt
@@ -95,8 +95,8 @@ class FirTowerResolver(
                 )
             }
             if (implicitDispatchReceiverValue is ImplicitDispatchReceiverValue) {
-                val implicitCompanionScope = implicitDispatchReceiverValue.implicitCompanionScope
-                if (implicitCompanionScope != null) {
+                val implicitCompanionScopes = implicitDispatchReceiverValue.implicitCompanionScopes
+                for (implicitCompanionScope in implicitCompanionScopes) {
                     // Extension in companion
                     // class My {
                     //     companion object { fun My.foo() {} }
@@ -184,8 +184,8 @@ class FirTowerResolver(
                 towerDataConsumer.consume(TOWER_LEVEL, ScopeTowerLevel(session, components, implicitScope), group++)
             }
             if (implicitReceiverValue is ImplicitDispatchReceiverValue) {
-                val implicitCompanionScope = implicitReceiverValue.implicitCompanionScope
-                if (implicitCompanionScope != null) {
+                val implicitCompanionScopes = implicitReceiverValue.implicitCompanionScopes
+                for (implicitCompanionScope in implicitCompanionScopes) {
                     // Companion scope bound to implicit receiver scope
                     // class Outer {
                     //     companion object { val x = 0 }
diff --git a/compiler/fir/resolve/testData/resolve/expresssions/protectedVisibility.kt b/compiler/fir/resolve/testData/resolve/expresssions/protectedVisibility.kt
index b405cbbeb99..a705f24d682 100644
--- a/compiler/fir/resolve/testData/resolve/expresssions/protectedVisibility.kt
+++ b/compiler/fir/resolve/testData/resolve/expresssions/protectedVisibility.kt
@@ -19,6 +19,12 @@ open class Protected {
 
         protected fun bar() {}
     }
+
+    protected companion object {
+        fun fromCompanion() {}
+
+        protected fun protectedFromCompanion() {}
+    }
 }
 
 class Derived : Protected() {
@@ -26,9 +32,12 @@ class Derived : Protected() {
         bar()
         Nested().foo()
         Nested().<!INAPPLICABLE_CANDIDATE!>bar<!>() // hidden
+
+        fromCompanion()
+        <!INAPPLICABLE_CANDIDATE!>protectedFromCompanion<!>()
     }
 
-    class NestedDerived : Nested() {
+    private class NestedDerived : Nested() {
         fun use() {
             bar()
         }
diff --git a/compiler/fir/resolve/testData/resolve/expresssions/protectedVisibility.txt b/compiler/fir/resolve/testData/resolve/expresssions/protectedVisibility.txt
index 705ff6774ce..cd0ae840709 100644
--- a/compiler/fir/resolve/testData/resolve/expresssions/protectedVisibility.txt
+++ b/compiler/fir/resolve/testData/resolve/expresssions/protectedVisibility.txt
@@ -37,6 +37,19 @@ FILE: protectedVisibility.kt
 
         }
 
+        protected final companion object Companion : R|kotlin/Any| {
+            private constructor(): R|Protected.Companion| {
+                super<R|kotlin/Any|>()
+            }
+
+            public final fun fromCompanion(): R|kotlin/Unit| {
+            }
+
+            protected final fun protectedFromCompanion(): R|kotlin/Unit| {
+            }
+
+        }
+
     }
     public final class Derived : R|Protected| {
         public constructor(): R|Derived| {
@@ -47,9 +60,11 @@ FILE: protectedVisibility.kt
             this@R|/Protected|.R|/Protected.bar|()
             R|/Protected.Nested.Nested|().R|/Protected.Nested.foo|()
             R|/Protected.Nested.Nested|().<Inapplicable(HIDDEN): [/Protected.Nested.bar]>#()
+            this@R|/Protected.Companion|.R|/Protected.Companion.fromCompanion|()
+            <Inapplicable(HIDDEN): [/Protected.Companion.protectedFromCompanion]>#()
         }
 
-        public final class NestedDerived : R|Protected.Nested| {
+        private final class NestedDerived : R|Protected.Nested| {
             public constructor(): R|Derived.NestedDerived| {
                 super<R|Protected.Nested|>()
             }