Support for import aliases in code completion

#KT-8848 Fixed

compiler/frontend/src/org/jetbrains/kotlin/resolve/AllUnderImportScope.kt

@@ -49,7 +49,11 @@ class AllUnderImportScope(
         excludedImportNames.mapNotNull { if (it.parent() == fqName) it.shortName() else null }.toSet()
     }
 
-    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): List<DeclarationDescriptor> {
+    override fun getContributedDescriptors(
+            kindFilter: DescriptorKindFilter,
+            nameFilter: (Name) -> Boolean,
+            changeNamesForAliased: Boolean
+    ): Collection<DeclarationDescriptor> {
         val nameFilterToUse = if (excludedNames.isEmpty()) { // optimization
             nameFilter
         }

compiler/frontend/src/org/jetbrains/kotlin/resolve/LazyExplicitImportScope.kt

@@ -57,12 +57,47 @@ class LazyExplicitImportScope(
         return collectCallableMemberDescriptors(location, MemberScope::getContributedVariables)
     }
 
-    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<DeclarationDescriptor> {
+    override fun getContributedDescriptors(
+            kindFilter: DescriptorKindFilter,
+            nameFilter: (Name) -> Boolean,
+            changeNamesForAliased: Boolean
+    ): Collection<DeclarationDescriptor> {
         val descriptors = SmartList<DeclarationDescriptor>()
+
         descriptors.addIfNotNull(getContributedClassifier(aliasName, NoLookupLocation.WHEN_GET_ALL_DESCRIPTORS))
         descriptors.addAll(getContributedFunctions(aliasName, NoLookupLocation.WHEN_GET_ALL_DESCRIPTORS))
         descriptors.addAll(getContributedVariables(aliasName, NoLookupLocation.WHEN_GET_ALL_DESCRIPTORS))
 
+        if (changeNamesForAliased && aliasName != declaredName) {
+            for (i in descriptors.indices) {
+                val descriptor = descriptors[i]
+                val newDescriptor: DeclarationDescriptor = when (descriptor) {
+                    is ClassDescriptor -> {
+                        object : ClassDescriptor by descriptor {
+                            override fun getName() = aliasName
+                        }
+                    }
+
+                    is TypeAliasDescriptor -> {
+                        object : TypeAliasDescriptor by descriptor {
+                            override fun getName() = aliasName
+                        }
+                    }
+
+                    is CallableMemberDescriptor -> {
+                        descriptor
+                                .newCopyBuilder()
+                                .setName(aliasName)
+                                .setOriginal(descriptor)
+                                .build()!!
+                    }
+
+                    else -> error("Unknown kind of descriptor in import alias: $descriptor")
+                }
+                descriptors[i] = newDescriptor
+            }
+        }
+
         return descriptors
     }
 

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/FileScopeFactory.kt

@@ -208,7 +208,11 @@ class FileScopeFactory(
                 return scope.getContributedFunctions(name, location)
             }
 
-            override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<DeclarationDescriptor> {
+            override fun getContributedDescriptors(
+                    kindFilter: DescriptorKindFilter,
+                    nameFilter: (Name) -> Boolean,
+                    changeNamesForAliased: Boolean
+            ): Collection<DeclarationDescriptor> {
                 // we do not perform any filtering by visibility here because all descriptors from both visible/invisible filter scopes are to be added anyway
                 if (filteringKind == FilteringKind.INVISIBLE_CLASSES) return listOf()
                 return scope.getContributedDescriptors(

compiler/frontend/src/org/jetbrains/kotlin/resolve/lazy/LazyImportScope.kt

@@ -238,7 +238,11 @@ class LazyImportScope(
         return importResolver.collectFromImports(name) { scope, name -> scope.getContributedFunctions(name, location) }
     }
 
-    override fun getContributedDescriptors(kindFilter: DescriptorKindFilter, nameFilter: (Name) -> Boolean): Collection<DeclarationDescriptor> {
+    override fun getContributedDescriptors(
+            kindFilter: DescriptorKindFilter,
+            nameFilter: (Name) -> Boolean,
+            changeNamesForAliased: Boolean
+    ): Collection<DeclarationDescriptor> {
         // we do not perform any filtering by visibility here because all descriptors from both visible/invisible filter scopes are to be added anyway
         if (filteringKind == FilteringKind.INVISIBLE_CLASSES) return listOf()
 
@@ -248,7 +252,7 @@ class LazyImportScope(
                 val importPath = directive.importPath ?: continue
                 val importedName = importPath.importedName
                 if (importedName == null || nameFilter(importedName)) {
-                    descriptors.addAll(importResolver.getImportScope(directive).getContributedDescriptors(kindFilter, nameFilter))
+                    descriptors.addAll(importResolver.getImportScope(directive).getContributedDescriptors(kindFilter, nameFilter, changeNamesForAliased))
                 }
             }
             descriptors