FIR: add getClassifierNames for FirScope

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/scopes/JavaClassUseSiteMemberScope.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 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.
  */
 
@@ -49,6 +49,10 @@ class JavaClassUseSiteMemberScope(
         return declaredMemberScope.getCallableNames() + superTypesScope.getCallableNames()
     }
 
+    override fun getClassifierNames(): Set<Name> {
+        return declaredMemberScope.getClassifierNames() + superTypesScope.getClassifierNames()
+    }
+
     private fun generateAccessorSymbol(
         functionSymbol: FirFunctionSymbol<*>,
         syntheticPropertyName: Name,

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/scopes/impl/FirClassDeclaredMemberScope.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 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.
  */
 
@@ -80,6 +80,10 @@ class FirClassDeclaredMemberScope(
     override fun getCallableNames(): Set<Name> {
         return callablesIndex.keys
     }
+
+    override fun getClassifierNames(): Set<Name> {
+        return nestedClassifierScope?.getClassifierNames().orEmpty()
+    }
 }
 
 

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/scopes/impl/FirLazyNestedClassifierScope.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 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.
  */
 
@@ -32,4 +32,8 @@ class FirLazyNestedClassifierScope(
 
         processor(symbol, ConeSubstitutor.Empty)
     }
+
+    override fun getClassifierNames(): Set<Name> {
+        return existingNames.toSet()
+    }
 }

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/scopes/impl/FirNestedClassifierScope.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2018 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 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.
  */
 
@@ -43,6 +43,10 @@ class FirNestedClassifierScope(val klass: FirClass<*>) : FirScope() {
     }
 
     fun getClassifierByName(name: Name): FirRegularClassSymbol? = classIndex[name]
+
+    override fun getClassifierNames(): Set<Name> {
+        return classIndex.keys
+    }
 }
 
 fun FirTypeParameterRef.toConeType(): ConeKotlinType = ConeTypeParameterTypeImpl(ConeTypeParameterLookupTag(symbol), isNullable = false)

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/scopes/impl/FirTypeIntersectionScope.kt

@@ -1,6 +1,6 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license
- * that can be found in the license/LICENSE.txt file.
+ * Copyright 2010-2020 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.fir.scopes.impl
@@ -345,6 +345,10 @@ class FirTypeIntersectionScope private constructor(
         return scopes.flatMapTo(mutableSetOf()) { it.getCallableNames() }
     }
 
+    override fun getClassifierNames(): Set<Name> {
+        return scopes.flatMapTo(hashSetOf()) { it.getClassifierNames() }
+    }
+
     companion object {
         fun prepareIntersectionScope(
             session: FirSession,

compiler/fir/tree/src/org/jetbrains/kotlin/fir/scopes/FirCompositeScope.kt

@@ -48,4 +48,8 @@ class FirCompositeScope(private val scopes: Iterable<FirScope>) : FirScope() {
     override fun getCallableNames(): Set<Name> {
         return scopes.flatMapTo(mutableSetOf()) { it.getCallableNames() }
     }
+
+    override fun getClassifierNames(): Set<Name> {
+        return scopes.flatMapTo(hashSetOf()) { it.getClassifierNames() }
+    }
 }

compiler/fir/tree/src/org/jetbrains/kotlin/fir/scopes/FirScope.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2019 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Copyright 2010-2020 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.
  */
 
@@ -35,6 +35,8 @@ abstract class FirScope {
     open fun mayContainName(name: Name) = true
 
     open fun getCallableNames(): Set<Name> = emptySet()
+
+    open fun getClassifierNames(): Set<Name> = emptySet()
 }
 
 fun FirTypeScope.processOverriddenFunctionsAndSelf(