KT-15796 Import of class referenced only in KDoc not preserved after copy-paste

#KT-15796 fixed

compiler/frontend/src/org/jetbrains/kotlin/kdoc/psi/api/KDoc.kt

@@ -22,7 +22,7 @@ import org.jetbrains.kotlin.psi.KtDeclaration
 import org.jetbrains.kotlin.kdoc.parser.KDocKnownTag
 
 // Don't implement JetElement (or it will be treated as statement)
-interface KDoc : PsiComment {
+interface KDoc : PsiComment, KDocElement {
     fun getOwner(): KtDeclaration?
     fun getDefaultSection(): KDocSection
     fun findSectionByName(name: String): KDocSection?

compiler/frontend/src/org/jetbrains/kotlin/kdoc/psi/impl/KDocElementImpl.java

@@ -21,8 +21,9 @@ import com.intellij.lang.ASTNode;
 import com.intellij.lang.Language;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.kotlin.idea.KotlinLanguage;
+import org.jetbrains.kotlin.kdoc.psi.api.KDocElement;
 
-public abstract class KDocElementImpl extends ASTWrapperPsiElement {
+public abstract class KDocElementImpl extends ASTWrapperPsiElement implements KDocElement {
     @NotNull
     @Override
     public Language getLanguage() {

idea/src/org/jetbrains/kotlin/idea/codeInsight/KotlinCopyPasteReferenceProcessor.kt

@@ -40,11 +40,13 @@ import org.jetbrains.kotlin.idea.conversion.copy.end
 import org.jetbrains.kotlin.idea.conversion.copy.range
 import org.jetbrains.kotlin.idea.conversion.copy.start
 import org.jetbrains.kotlin.idea.imports.importableFqName
+import org.jetbrains.kotlin.idea.kdoc.KDocReference
 import org.jetbrains.kotlin.idea.references.*
 import org.jetbrains.kotlin.idea.util.ImportInsertHelper
 import org.jetbrains.kotlin.idea.util.application.runWriteAction
 import org.jetbrains.kotlin.idea.util.getFileResolutionScope
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
+import org.jetbrains.kotlin.kdoc.psi.api.KDocElement
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.collectDescendantsOfType
@@ -124,7 +126,9 @@ class KotlinCopyPasteReferenceProcessor : CopyPastePostProcessor<KotlinReference
             endOffsets: IntArray
     ): List<KotlinReferenceData> {
         val ranges = toTextRanges(startOffsets, endOffsets)
-        val elementsByRange = ranges.associateBy({ it }, { file.elementsInRange(it).filterIsInstance<KtElement>() })
+        val elementsByRange = ranges.associateBy({ it }, {
+            file.elementsInRange(it).filter { it is KtElement || it is KDocElement }
+        })
 
         val allElementsToResolve = elementsByRange.values.flatMap { it }.flatMap { it.collectDescendantsOfType<KtElement>() }
         val bindingContext = file.getResolutionFacade().analyze(allElementsToResolve, BodyResolveMode.PARTIAL)
@@ -139,7 +143,7 @@ class KotlinCopyPasteReferenceProcessor : CopyPastePostProcessor<KotlinReference
     }
 
     private fun MutableCollection<KotlinReferenceData>.addReferenceDataInsideElement(
-            element: KtElement,
+            element: PsiElement,
             file: KtFile,
             startOffset: Int,
             startOffsets: IntArray,
@@ -300,21 +304,27 @@ class KotlinCopyPasteReferenceProcessor : CopyPastePostProcessor<KotlinReference
         )
 
         val bindingRequests = ArrayList<BindingRequest>()
-        val extensionsToImport = ArrayList<CallableDescriptor>()
+        val descriptorsToImport = ArrayList<DeclarationDescriptor>()
+
         for ((reference, refData) in referencesToRestore) {
             val fqName = FqName(refData.fqName)
 
-            if (!refData.kind.isExtension() && reference is KtSimpleNameReference) {
+            if (!refData.kind.isExtension()) {
-                val pointer = smartPointerManager.createSmartPsiElementPointer(reference.element, file)
+                if (reference is KtSimpleNameReference) {
-                bindingRequests.add(BindingRequest(pointer, fqName))
+                    val pointer = smartPointerManager.createSmartPsiElementPointer(reference.element, file)
+                    bindingRequests.add(BindingRequest(pointer, fqName))
+                }
+                else if (reference is KDocReference) {
+                    descriptorsToImport.addAll(findImportableDescriptors(fqName, file))
+                }
             }
 
             if (refData.kind.isExtension()) {
-                extensionsToImport.addIfNotNull(findCallableToImport(fqName, file))
+                descriptorsToImport.addIfNotNull(findCallableToImport(fqName, file))
             }
         }
 
-        for (descriptor in extensionsToImport) {
+        for (descriptor in descriptorsToImport) {
             importHelper.importDescriptor(file, descriptor)
         }
         for ((pointer, fqName) in bindingRequests) {

idea/testData/copyPaste/imports/OnlyKDocReferenced.expected.kt

@@ -0,0 +1,9 @@
+import java.io.File
+
+/**
+ * [File]
+ */
+
+fun other() {
+
+}

idea/testData/copyPaste/imports/OnlyKDocReferenced.expected.names

@@ -0,0 +1 @@
+java.io.File

idea/testData/copyPaste/imports/OnlyKDocReferenced.kt

@@ -0,0 +1,12 @@
+// RUNTIME
+
+import java.io.File
+
+<selection>
+/**
+ * [File]
+ */
+</selection>
+fun some() {
+
+}

idea/testData/copyPaste/imports/OnlyKDocReferenced.to.kt

@@ -0,0 +1,4 @@
+<caret>
+fun other() {
+
+}

idea/tests/org/jetbrains/kotlin/idea/codeInsight/InsertImportOnPasteTestGenerated.java

@@ -320,6 +320,12 @@ public class InsertImportOnPasteTestGenerated extends AbstractInsertImportOnPast
             doTestCopy(fileName);
         }
 
+        @TestMetadata("OnlyKDocReferenced.kt")
+        public void testOnlyKDocReferenced() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/copyPaste/imports/OnlyKDocReferenced.kt");
+            doTestCopy(fileName);
+        }
+
         @TestMetadata("OverloadedExtensionFunction.kt")
         public void testOverloadedExtensionFunction() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/copyPaste/imports/OverloadedExtensionFunction.kt");
@@ -683,6 +689,12 @@ public class InsertImportOnPasteTestGenerated extends AbstractInsertImportOnPast
             doTestCut(fileName);
         }
 
+        @TestMetadata("OnlyKDocReferenced.kt")
+        public void testOnlyKDocReferenced() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/copyPaste/imports/OnlyKDocReferenced.kt");
+            doTestCut(fileName);
+        }
+
         @TestMetadata("OverloadedExtensionFunction.kt")
         public void testOverloadedExtensionFunction() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/copyPaste/imports/OverloadedExtensionFunction.kt");