Support for import aliases in code completion

#KT-8848 Fixed

compiler/resolution/src/org/jetbrains/kotlin/resolve/scopes/Scopes.kt

@@ -109,6 +109,16 @@ interface ImportingScope : HierarchicalScope {
 
     fun getContributedPackage(name: Name): PackageViewDescriptor?
 
+    fun getContributedDescriptors(
+            kindFilter: DescriptorKindFilter = DescriptorKindFilter.ALL,
+            nameFilter: (Name) -> Boolean = MemberScope.ALL_NAME_FILTER,
+            changeNamesForAliased: Boolean
+    ): Collection<DeclarationDescriptor>
+
+    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<DeclarationDescriptor> {
+        return getContributedDescriptors(kindFilter, nameFilter, changeNamesForAliased = false)
+    }
+
     object Empty : BaseImportingScope(null) {
         override fun printStructure(p: Printer) {
             p.println("ImportingScope.Empty")
@@ -131,4 +141,11 @@ abstract class BaseImportingScope(parent: ImportingScope?) : BaseHierarchicalSco
         get() = super.parent as ImportingScope?
 
     override fun getContributedPackage(name: Name): PackageViewDescriptor? = null
+
+    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<DeclarationDescriptor> {
+        return getContributedDescriptors(kindFilter, nameFilter, changeNamesForAliased = false)
+    }
+
+    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean, changeNamesForAliased: Boolean): Collection<DeclarationDescriptor>
+            = emptyList()
 }

compiler/resolution/src/org/jetbrains/kotlin/resolve/scopes/SubpackagesImportingScope.kt

@@ -40,12 +40,12 @@ class SubpackagesImportingScope(
     override fun getContributedFunctions(name: Name, location: LookupLocation) = super.getContributedFunctions(name, location)
 
     //TODO: kept old behavior, but it seems very strange (super call seems more applicable)
-    override fun getContributedClassifier(name: Name, location: LookupLocation): ClassifierDescriptor? {
-        return ImportingScope.Empty.getContributedClassifier(name, location)
-    }
+    override fun getContributedClassifier(name: Name, location: LookupLocation): ClassifierDescriptor? = null
+
+    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<DeclarationDescriptor> =
+            emptyList()
 
     //TODO: kept old behavior, but it seems very strange (super call seems more applicable)
-    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<DeclarationDescriptor> {
-        return ImportingScope.Empty.getContributedDescriptors(kindFilter, nameFilter)
-    }
+    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean, changeNamesForAliased: Boolean): Collection<DeclarationDescriptor>
+            = emptyList()
 }

compiler/resolution/src/org/jetbrains/kotlin/resolve/scopes/utils/ScopeUtils.kt

@@ -50,14 +50,18 @@ fun LexicalScope.getDeclarationsByLabel(labelName: Name): Collection<Declaration
 // Result is guaranteed to be filtered by kind and name.
 fun HierarchicalScope.collectDescriptorsFiltered(
         kindFilter: DescriptorKindFilter = DescriptorKindFilter.ALL,
-        nameFilter: (Name) -> Boolean = { true }
+        nameFilter: (Name) -> Boolean = { true },
+        changeNamesForAliased: Boolean = false
 ): Collection<DeclarationDescriptor> {
     if (kindFilter.kindMask == 0) return listOf()
-    return collectAllFromMeAndParent { it.getContributedDescriptors(kindFilter, nameFilter) }
-            .filter { kindFilter.accepts(it) && nameFilter(it.name) }
+    return collectAllFromMeAndParent {
+        if (it is ImportingScope)
+            it.getContributedDescriptors(kindFilter, nameFilter, changeNamesForAliased)
+        else
+            it.getContributedDescriptors(kindFilter, nameFilter)
+    }.filter { kindFilter.accepts(it) && nameFilter(it.name) }
 }
 
-
 @Deprecated("Use getContributedProperties instead") fun LexicalScope.findLocalVariable(name: Name): VariableDescriptor? {
     return findFirstFromMeAndParent {
         when {
@@ -103,7 +107,7 @@ fun HierarchicalScope.takeSnapshot(): HierarchicalScope = if (this is LexicalWri
 private class MemberScopeToImportingScopeAdapter(override val parent: ImportingScope?, val memberScope: MemberScope) : ImportingScope {
     override fun getContributedPackage(name: Name): PackageViewDescriptor? = null
 
-    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean)
+    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean, changeNamesForAliased: Boolean)
             = memberScope.getContributedDescriptors(kindFilter, nameFilter)
 
     override fun getContributedClassifier(name: Name, location: LookupLocation) = memberScope.getContributedClassifier(name, location)