Introduce MemberScope::classifierNames and some implementations

It aims to help with further optimizations

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/descriptors/LazyPackageMemberScope.kt

@@ -58,6 +58,7 @@ class LazyPackageMemberScope(
         c.lookupTracker.record(from, thisDescriptor, name)
     }
 
+    override fun getClassifierNames(): Set<Name>? = declarationProvider.getDeclarationNames()
     override fun getFunctionNames() = declarationProvider.getDeclarationNames()
     override fun getVariableNames() = declarationProvider.getDeclarationNames()
 

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/lazy/descriptors/JvmPackageScope.kt

@@ -27,6 +27,7 @@ import org.jetbrains.kotlin.load.java.structure.JavaPackage
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.scopes.DescriptorKindFilter
 import org.jetbrains.kotlin.resolve.scopes.MemberScope
+import org.jetbrains.kotlin.resolve.scopes.flatMapClassifierNamesOrNull
 import org.jetbrains.kotlin.storage.getValue
 import org.jetbrains.kotlin.util.collectionUtils.getFirstClassifierDiscriminateHeaders
 import org.jetbrains.kotlin.util.collectionUtils.getFromAllScopes
@@ -76,6 +77,10 @@ class JvmPackageScope(
         addAll(javaScope.getVariableNames())
     }
 
+    override fun getClassifierNames(): Set<Name>? = kotlinScopes.flatMapClassifierNamesOrNull()?.apply {
+        addAll(javaScope.getClassifierNames())
+    }
+
     override fun printScopeStructure(p: Printer) {
         p.println(this::class.java.simpleName, " {")
         p.pushIndent()

core/descriptor.loader.java/src/org/jetbrains/kotlin/load/java/lazy/descriptors/LazyJavaScope.kt

@@ -212,9 +212,11 @@ abstract class LazyJavaScope(protected val c: LazyJavaResolverContext) : MemberS
 
     private val functionNamesLazy by c.storageManager.createLazyValue { computeFunctionNames(DescriptorKindFilter.FUNCTIONS, null) }
     private val propertyNamesLazy by c.storageManager.createLazyValue { computePropertyNames(DescriptorKindFilter.VARIABLES, null) }
+    private val classNamesLazy by c.storageManager.createLazyValue { computeClassNames(DescriptorKindFilter.CLASSIFIERS, null) }
 
     override fun getFunctionNames() = functionNamesLazy
     override fun getVariableNames() = propertyNamesLazy
+    override fun getClassifierNames() = classNamesLazy
 
     override fun getContributedFunctions(name: Name, location: LookupLocation): Collection<SimpleFunctionDescriptor> {
         if (name !in getFunctionNames()) return emptyList()

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/EnumEntrySyntheticClassDescriptor.java

@@ -310,6 +310,12 @@ public class EnumEntrySyntheticClassDescriptor extends ClassDescriptorBase {
             return enumMemberNames.invoke();
         }
 
+        @NotNull
+        @Override
+        public Set<Name> getClassifierNames() {
+            return Collections.emptySet();
+        }
+
         @NotNull
         @Override
         public Set<Name> getVariableNames() {

core/descriptors/src/org/jetbrains/kotlin/descriptors/impl/SubpackagesScope.kt

@@ -57,6 +57,8 @@ open class SubpackagesScope(private val moduleDescriptor: ModuleDescriptor, priv
         return result
     }
 
+    override fun getClassifierNames(): Set<Name> = emptySet()
+
     override fun printScopeStructure(p: Printer) {
         p.println(this::class.java.simpleName, " {")
         p.pushIndent()

core/descriptors/src/org/jetbrains/kotlin/resolve/scopes/AbstractScopeAdapter.kt

@@ -55,6 +55,8 @@ abstract class AbstractScopeAdapter : MemberScope {
 
     override fun getFunctionNames() = workerScope.getFunctionNames()
     override fun getVariableNames() = workerScope.getVariableNames()
+    override fun getClassifierNames() = workerScope.getClassifierNames()
+
 
     override fun printScopeStructure(p: Printer) {
         p.println(this::class.java.simpleName, " {")

core/descriptors/src/org/jetbrains/kotlin/resolve/scopes/ChainedMemberScope.kt

@@ -43,6 +43,7 @@ class ChainedMemberScope(
 
     override fun getFunctionNames() = scopes.flatMapTo(mutableSetOf()) { it.getFunctionNames() }
     override fun getVariableNames() = scopes.flatMapTo(mutableSetOf()) { it.getVariableNames() }
+    override fun getClassifierNames(): Set<Name>? = scopes.flatMapClassifierNamesOrNull()
 
     override fun toString() = debugName
 

core/descriptors/src/org/jetbrains/kotlin/resolve/scopes/InnerClassesScopeWrapper.kt

@@ -40,6 +40,10 @@ class InnerClassesScopeWrapper(val workerScope: MemberScope) : MemberScopeImpl()
         workerScope.printScopeStructure(p)
     }
 
+    override fun getFunctionNames() = workerScope.getFunctionNames()
+    override fun getVariableNames() = workerScope.getVariableNames()
+    override fun getClassifierNames() = workerScope.getClassifierNames()
+
     override fun definitelyDoesNotContainName(name: Name) = workerScope.definitelyDoesNotContainName(name)
 
     override fun toString() = "Classes from $workerScope"

core/descriptors/src/org/jetbrains/kotlin/resolve/scopes/MemberScope.kt

@@ -20,6 +20,7 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.incremental.components.LookupLocation
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.utils.Printer
+import org.jetbrains.kotlin.utils.addToStdlib.flatMapToNullable
 import java.lang.reflect.Modifier
 
 interface MemberScope : ResolutionScope {
@@ -32,6 +33,7 @@ interface MemberScope : ResolutionScope {
      */
     fun getFunctionNames(): Set<Name>
     fun getVariableNames(): Set<Name>
+    fun getClassifierNames(): Set<Name>?
 
     /**
      * Is supposed to be used in tests and debug only
@@ -45,6 +47,7 @@ interface MemberScope : ResolutionScope {
 
         override fun getFunctionNames() = emptySet<Name>()
         override fun getVariableNames() = emptySet<Name>()
+        override fun getClassifierNames() = emptySet<Name>()
     }
 
     companion object {
@@ -52,6 +55,11 @@ interface MemberScope : ResolutionScope {
     }
 }
 
+fun MemberScope.computeAllNames() = getClassifierNames()?.let { getFunctionNames() + getVariableNames() + it }
+
+fun Collection<MemberScope>.flatMapClassifierNamesOrNull(): MutableSet<Name>? =
+        flatMapToNullable(hashSetOf(), MemberScope::getClassifierNames)
+
 /**
  * The same as getDescriptors(kindFilter, nameFilter) but the result is guaranteed to be filtered by kind and name.
  */

core/descriptors/src/org/jetbrains/kotlin/resolve/scopes/MemberScopeImpl.kt

@@ -42,6 +42,8 @@ abstract class MemberScopeImpl : MemberScope {
                     DescriptorKindFilter.VARIABLES, alwaysTrue()
             ).filterIsInstance<VariableDescriptor>().mapTo(mutableSetOf()) { it.name }
 
+    override fun getClassifierNames(): Set<Name>? = null
+
     // This method should not be implemented here by default: every scope class has its unique structure pattern
     abstract override fun printScopeStructure(p: Printer)
 }

core/descriptors/src/org/jetbrains/kotlin/resolve/scopes/SubstitutingScope.kt

@@ -81,6 +81,7 @@ class SubstitutingScope(private val workerScope: MemberScope, givenSubstitutor:
 
     override fun getFunctionNames() = workerScope.getFunctionNames()
     override fun getVariableNames() = workerScope.getVariableNames()
+    override fun getClassifierNames() = workerScope.getClassifierNames()
 
     override fun definitelyDoesNotContainName(name: Name) = workerScope.definitelyDoesNotContainName(name)
 

core/descriptors/src/org/jetbrains/kotlin/types/ErrorUtils.java

@@ -211,6 +211,12 @@ public class ErrorUtils {
             return emptySet();
         }
 
+        @NotNull
+        @Override
+        public Set<Name> getClassifierNames() {
+            return emptySet();
+        }
+
         @NotNull
         @Override
         public Collection<DeclarationDescriptor> getContributedDescriptors(
@@ -284,6 +290,11 @@ public class ErrorUtils {
             throw new IllegalStateException();
         }
 
+        @Override
+        public Set<Name> getClassifierNames() {
+            throw new IllegalStateException();
+        }
+
         @Override
         public boolean definitelyDoesNotContainName(@NotNull Name name) {
             return false;

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/MetadataPackageFragmentProvider.kt

@@ -107,6 +107,7 @@ class MetadataPackageFragment(
         ) {
             override fun hasClass(name: Name): Boolean = hasTopLevelClass(name)
             override fun definitelyDoesNotContainName(name: Name) = false
+            override fun getClassifierNames(): Set<Name>? = null
         })
 
         return ChainedMemberScope.create("Metadata scope", scopes)

core/deserialization/src/org/jetbrains/kotlin/serialization/deserialization/descriptors/DeserializedMemberScope.kt

@@ -76,6 +76,7 @@ abstract class DeserializedMemberScope protected constructor(
 
     override fun getFunctionNames() = functionNamesLazy
     override fun getVariableNames() = variableNamesLazy
+    override fun getClassifierNames(): Set<Name>? = classNames + typeAliasNames
 
     private inline fun <M : MessageLite> Collection<M>.groupByName(
             getNameIndex: (M) -> Int

core/util.runtime/src/org/jetbrains/kotlin/utils/addToStdlib.kt

@@ -138,3 +138,11 @@ fun <T, C : MutableCollection<in T>> Iterable<Iterable<T>>.flattenTo(c: C): C {
     }
     return c
 }
+
+inline fun <T, R, C : MutableCollection<in R>> Iterable<T>.flatMapToNullable(destination: C, transform: (T) -> Iterable<R>?): C? {
+    for (element in this) {
+        val list = transform(element) ?: return null
+        destination.addAll(list)
+    }
+    return destination
+}

idea/ide-common/src/org/jetbrains/kotlin/idea/kdoc/resolveKDocLink.kt

@@ -253,6 +253,8 @@ private class ExtensionsScope(
                 .toSet()
     }
 
+    override fun getClassifierNames() = null
+
     override fun printScopeStructure(p: Printer) {
         p.println("Extensions for ${receiverClass.name} in:")
         contextScope.printStructure(p)

idea/idea-analysis/src/org/jetbrains/kotlin/idea/kdoc/IdeSampleResolutionService.kt

@@ -75,8 +75,8 @@ private class GlobalSyntheticPackageViewDescriptor(override val fqName: FqName,
         override fun getContributedFunctions(name: Name, location: LookupLocation): Collection<SimpleFunctionDescriptor> = shouldNotBeCalled()
 
         override fun getFunctionNames(): Set<Name> = shouldNotBeCalled()
-
         override fun getVariableNames(): Set<Name> = shouldNotBeCalled()
+        override fun getClassifierNames(): Set<Name> = shouldNotBeCalled()
 
         override fun getContributedClassifier(name: Name, location: LookupLocation): ClassifierDescriptor? = shouldNotBeCalled()