Import insertion algorithm

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/resolve/KotlinCacheService.kt

@@ -39,6 +39,7 @@ import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.psi.JetDeclaration
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
+import org.jetbrains.kotlin.resolve.scopes.JetScope
 
 private val LOG = Logger.getInstance(javaClass<KotlinCacheService>())
 
@@ -66,6 +67,10 @@ public class KotlinCacheService(val project: Project) {
                 return cache.getAnalysisResultsForElements(elements)
             }
 
+            override fun getFileTopLevelScope(file: JetFile): JetScope {
+                return getLazyResolveSession(file).getScopeProvider().getFileScope(file)
+            }
+
             override fun <T> get(extension: CacheExtension<T>): T {
                 return cache[extension]
             }

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/resolve/ResolutionFacade.kt

@@ -23,6 +23,8 @@ import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.psi.JetDeclaration
 import org.jetbrains.kotlin.analyzer.AnalysisResult
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
+import org.jetbrains.kotlin.psi.JetFile
+import org.jetbrains.kotlin.resolve.scopes.JetScope
 
 public trait ResolutionFacade {
 
@@ -32,6 +34,8 @@ public trait ResolutionFacade {
 
     public fun resolveToDescriptor(declaration: JetDeclaration): DeclarationDescriptor
 
+    public fun getFileTopLevelScope(file: JetFile): JetScope
+
     public fun findModuleDescriptor(element: JetElement): ModuleDescriptor
 
     public fun <T> get(extension: CacheExtension<T>): T

idea/idea-analysis/src/org/jetbrains/kotlin/idea/codeInsight/ShortenReferences.kt

@@ -27,16 +27,15 @@ import com.intellij.psi.util.PsiTreeUtil
 import com.intellij.openapi.util.TextRange
 import com.intellij.psi.PsiDocumentManager
 import org.jetbrains.kotlin.idea.caches.resolve.getResolutionFacade
-import org.jetbrains.kotlin.resolve.DescriptorUtils
 import java.util.Collections
 import org.jetbrains.kotlin.analyzer.analyzeInContext
 import org.jetbrains.kotlin.resolve.calls.callUtil.getCalleeExpressionIfAny
 import java.util.LinkedHashSet
-import org.jetbrains.kotlin.resolve.ImportPath
 import org.jetbrains.kotlin.psi.psiUtil.getQualifiedElement
 import org.jetbrains.kotlin.resolve.descriptorUtil.getImportableDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.ResolutionFacade
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
+import org.jetbrains.kotlin.resolve.DescriptorUtils
 
 public object ShortenReferences {
     public fun process(element: JetElement) {
@@ -303,17 +302,9 @@ public object ShortenReferences {
         private var optimizeImports = true
 
         fun addImport(target: DeclarationDescriptor): Boolean {
-            val realTarget = if (DescriptorUtils.isClassObject(target)) // references to class object are treated as ones to its owner class
-                target.getContainingDeclaration() as? ClassDescriptor ?: return false
-            else
-                target
-
-            if (realTarget !is ClassDescriptor && realTarget !is PackageViewDescriptor) return false
-            if (realTarget.getContainingDeclaration() is ClassDescriptor) return false // do not insert imports for nested classes
-
+            if (target !is ClassDescriptor && target !is PackageViewDescriptor) return false
             optimizeImports()
-            ImportInsertHelper.INSTANCE.writeImportToFile(ImportPath(DescriptorUtils.getFqNameSafe(realTarget), false), file)
-            return true
+            return ImportInsertHelper.INSTANCE.importDescriptor(file, target)
         }
 
         fun optimizeImports(): Boolean {

idea/idea-analysis/src/org/jetbrains/kotlin/idea/quickfix/ImportInsertHelper.kt

@@ -21,6 +21,8 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.JetFile
 import org.jetbrains.kotlin.psi.JetImportDirective
 import org.jetbrains.kotlin.resolve.ImportPath
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.idea.caches.resolve.ResolutionFacade
 
 public trait ImportInsertHelper {
 
@@ -34,7 +36,13 @@ public trait ImportInsertHelper {
 
     public fun needImport(importPath: ImportPath, file: JetFile, importDirectives: List<JetImportDirective> = file.getImportDirectives()): Boolean
 
-    public fun writeImportToFile(importPath: ImportPath, file: JetFile)
+    public fun writeImportToFile(importPath: ImportPath, file: JetFile): JetImportDirective
+
+    /**
+     * Returns true, if the descriptor is imported (even if no import was added because it's not needed)
+     * and false, if importing of this descriptor is either impossible or not allowed by code style.
+     */
+    public fun importDescriptor(file: JetFile, descriptor: DeclarationDescriptor): Boolean
 
     class object {
         public val INSTANCE: ImportInsertHelper