Introduce Type Alias: Support type constructor extraction

compiler/frontend/src/org/jetbrains/kotlin/psi/psiUtil/ktPsiUtil.kt

@@ -467,3 +467,8 @@ fun KtClassOrObject.findPropertyByName(name: String): KtNamedDeclaration? {
     return declarations.firstOrNull { it is KtProperty && it.name == name } as KtNamedDeclaration?
            ?: getPrimaryConstructorParameters().firstOrNull { it.hasValOrVar() && it.name == name }
 }
+
+fun isTypeConstructorReference(e: PsiElement): Boolean {
+    val parent = e.parent
+    return parent is KtUserType && parent.referenceExpression == e
+}

idea/src/org/jetbrains/kotlin/idea/codeInsight/CodeInsightUtils.java

@@ -31,6 +31,7 @@ import org.jetbrains.kotlin.descriptors.ClassKind;
 import org.jetbrains.kotlin.idea.caches.resolve.ResolutionUtils;
 import org.jetbrains.kotlin.lexer.KtTokens;
 import org.jetbrains.kotlin.psi.*;
+import org.jetbrains.kotlin.psi.psiUtil.KtPsiUtilKt;
 import org.jetbrains.kotlin.resolve.BindingContext;
 import org.jetbrains.kotlin.resolve.scopes.receivers.ClassQualifier;
 import org.jetbrains.kotlin.resolve.scopes.receivers.Qualifier;
@@ -57,12 +58,18 @@ public class CodeInsightUtils {
                 break;
             case TYPE_ELEMENT: elementClass = KtTypeElement.class;
                 break;
+            case TYPE_CONSTRUCTOR: elementClass = KtSimpleNameExpression.class;
+                break;
             default: throw new IllegalArgumentException(elementKind.name());
         }
         PsiElement element = findElementOfClassAtRange(file, startOffset, endOffset, elementClass);
 
         if (elementKind == ElementKind.TYPE_ELEMENT) return element;
 
+        if (elementKind == ElementKind.TYPE_CONSTRUCTOR) {
+            return element != null && KtPsiUtilKt.isTypeConstructorReference(element) ? element : null;
+        }
+
         if (element instanceof KtScriptInitializer) {
             element = ((KtScriptInitializer) element).getBody();
         }
@@ -106,7 +113,8 @@ public class CodeInsightUtils {
 
     public enum ElementKind {
         EXPRESSION,
-        TYPE_ELEMENT
+        TYPE_ELEMENT,
+        TYPE_CONSTRUCTOR
     }
 
     @NotNull
@@ -145,7 +153,8 @@ public class CodeInsightUtils {
 
         for (PsiElement element : array) {
             boolean correctType = kind == ElementKind.EXPRESSION && element instanceof KtExpression
-                                  || kind == ElementKind.TYPE_ELEMENT && element instanceof KtTypeElement;
+                                  || kind == ElementKind.TYPE_ELEMENT && element instanceof KtTypeElement
+                                  || kind == ElementKind.TYPE_CONSTRUCTOR && KtPsiUtilKt.isTypeConstructorReference(element);
             if (!(correctType
                   || element.getNode().getElementType() == KtTokens.SEMICOLON
                   || element instanceof PsiWhiteSpace

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/introduceTypeAlias/IntroduceTypeAliasHandler.kt

@@ -24,6 +24,7 @@ import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiElement
 import com.intellij.psi.PsiFile
 import com.intellij.refactoring.RefactoringActionHandler
+import org.jetbrains.kotlin.idea.codeInsight.CodeInsightUtils.ElementKind.TYPE_CONSTRUCTOR
 import org.jetbrains.kotlin.idea.codeInsight.CodeInsightUtils.ElementKind.TYPE_ELEMENT
 import org.jetbrains.kotlin.idea.refactoring.checkConflictsInteractively
 import org.jetbrains.kotlin.idea.refactoring.getExtractionContainers
@@ -34,8 +35,11 @@ import org.jetbrains.kotlin.idea.refactoring.introduce.selectElementsWithTargetS
 import org.jetbrains.kotlin.idea.refactoring.introduce.showErrorHint
 import org.jetbrains.kotlin.idea.util.application.executeWriteCommand
 import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.psi.KtSimpleNameExpression
 import org.jetbrains.kotlin.psi.KtTypeAlias
 import org.jetbrains.kotlin.psi.KtTypeElement
+import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
+import org.jetbrains.kotlin.psi.psiUtil.isTypeConstructorReference
 
 object KotlinIntroduceTypeAliasHandler : RefactoringActionHandler {
     @JvmField
@@ -47,7 +51,7 @@ object KotlinIntroduceTypeAliasHandler : RefactoringActionHandler {
                 editor,
                 file,
                 "Select target code block",
-                listOf(TYPE_ELEMENT),
+                listOf(TYPE_ELEMENT, TYPE_CONSTRUCTOR),
                 { elements, parent -> parent.getExtractionContainers(strict = true, includeAll = true) },
                 continuation
         )
@@ -69,9 +73,19 @@ object KotlinIntroduceTypeAliasHandler : RefactoringActionHandler {
             targetSibling: PsiElement,
             descriptorSubstitutor: ((IntroduceTypeAliasDescriptor) -> IntroduceTypeAliasDescriptor)? = null
     ) {
-        val typeElement = elements.singleOrNull() as? KtTypeElement
+        val elementToExtract = elements.singleOrNull()
-                       ?: return showErrorHint(project, editor, "No type to refactor", REFACTORING_NAME)
+
-        val introduceData = IntroduceTypeAliasData(typeElement, targetSibling)
+        val errorMessage = when (elementToExtract) {
+            is KtSimpleNameExpression -> if (!isTypeConstructorReference(elementToExtract)) "Type reference is expected" else null
+            !is KtTypeElement -> "No type to refactor"
+            else -> null
+        }
+        if (errorMessage != null) return showErrorHint(project, editor, errorMessage, REFACTORING_NAME)
+
+        val introduceData = when (elementToExtract) {
+            is KtTypeElement -> IntroduceTypeAliasData(elementToExtract, targetSibling)
+            else -> IntroduceTypeAliasData(elementToExtract!!.getStrictParentOfType<KtTypeElement>()!!, targetSibling, true)
+        }
         val analysisResult = introduceData.analyze()
         when (analysisResult) {
             is IntroduceTypeAliasAnalysisResult.Error -> {

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/introduceTypeAlias/extractionModel.kt

@@ -34,7 +34,8 @@ internal var KtTypeReference.resolveInfo : TypeReferenceInfo? by CopyableUserDat
 
 class IntroduceTypeAliasData(
         val originalType: KtTypeElement,
-        val targetSibling: PsiElement
+        val targetSibling: PsiElement,
+        val extractTypeConstructor: Boolean = false
 ) : Disposable {
     val resolutionFacade = originalType.getResolutionFacade()
     val bindingContext = resolutionFacade.analyze(originalType, BodyResolveMode.PARTIAL)

idea/src/org/jetbrains/kotlin/idea/refactoring/introduce/introduceTypeAlias/introduceTypeAliasImpl.kt

@@ -58,42 +58,48 @@ fun IntroduceTypeAliasData.analyze(): IntroduceTypeAliasAnalysisResult {
     val dummyVar = psiFactory.createProperty("val a: Int").apply {
         typeReference!!.replace(originalType.parent as? KtTypeReference ?: psiFactory.createType(originalType))
     }
-    val newReferences = dummyVar.typeReference!!.collectDescendantsOfType<KtTypeReference> { it.resolveInfo != null }
+    val newTypeReference = dummyVar.typeReference!!
+    val newReferences = newTypeReference.collectDescendantsOfType<KtTypeReference> { it.resolveInfo != null }
     val newContext = dummyVar.analyzeInContext(targetScope, contextExpression)
     val project = originalType.project
 
     val unifier = KotlinPsiUnifier.DEFAULT
-    val groupedBrokenReferences = LinkedMultiMap<TypeReferenceInfo, TypeReferenceInfo>()
+    val groupedReferencesToExtract = LinkedMultiMap<TypeReferenceInfo, TypeReferenceInfo>()
+
+    val forcedCandidates = if (extractTypeConstructor) newTypeReference.typeElement!!.typeArgumentsAsTypes else emptyList()
+
     for (newReference in newReferences) {
         val resolveInfo = newReference.resolveInfo!!
 
-        val originalDescriptor = resolveInfo.type.constructor.declarationDescriptor
+        if (newReference !in forcedCandidates) {
-        val newDescriptor = newContext[BindingContext.TYPE, newReference]?.constructor?.declarationDescriptor
+            val originalDescriptor = resolveInfo.type.constructor.declarationDescriptor
-        if (compareDescriptors(project, originalDescriptor, newDescriptor)) continue
+            val newDescriptor = newContext[BindingContext.TYPE, newReference]?.constructor?.declarationDescriptor
+            if (compareDescriptors(project, originalDescriptor, newDescriptor)) continue
+        }
 
-        val equivalenceRepresentative = groupedBrokenReferences
+        val equivalenceRepresentative = groupedReferencesToExtract
                 .keySet()
                 .firstOrNull { unifier.unify(it.reference, resolveInfo.reference).matched }
         if (equivalenceRepresentative != null) {
-            groupedBrokenReferences.putValue(equivalenceRepresentative, resolveInfo)
+            groupedReferencesToExtract.putValue(equivalenceRepresentative, resolveInfo)
         }
         else {
-            groupedBrokenReferences.putValue(resolveInfo, resolveInfo)
+            groupedReferencesToExtract.putValue(resolveInfo, resolveInfo)
         }
 
-        val brokenReferenceInfoIterator = groupedBrokenReferences.values().iterator()
+        val referencesToExtractIterator = groupedReferencesToExtract.values().iterator()
-        while (brokenReferenceInfoIterator.hasNext()) {
+        while (referencesToExtractIterator.hasNext()) {
-            val brokenReferenceInfo = brokenReferenceInfoIterator.next()
+            val referenceToExtract = referencesToExtractIterator.next()
-            if (resolveInfo.reference.isAncestor(brokenReferenceInfo.reference, true)) {
+            if (resolveInfo.reference.isAncestor(referenceToExtract.reference, true)) {
-                brokenReferenceInfoIterator.remove()
+                referencesToExtractIterator.remove()
             }
         }
     }
 
     val typeParameterNameValidator = CollectingNameValidator()
-    val brokenReferences = groupedBrokenReferences.keySet().filter { groupedBrokenReferences[it].isNotEmpty() }
+    val brokenReferences = groupedReferencesToExtract.keySet().filter { groupedReferencesToExtract[it].isNotEmpty() }
     val typeParameterNames = KotlinNameSuggester.suggestNamesForTypeParameters(brokenReferences.size, typeParameterNameValidator)
-    val typeParameters = (typeParameterNames zip brokenReferences).map { TypeParameter(it.first, groupedBrokenReferences[it.second]) }
+    val typeParameters = (typeParameterNames zip brokenReferences).map { TypeParameter(it.first, groupedReferencesToExtract[it.second]) }
 
     if (typeParameters.any { it.typeReferenceInfos.any { it.reference.typeElement == originalType } }) {
         return IntroduceTypeAliasAnalysisResult.Error("Type alias cannot refer to types which aren't accessible in the scope where it's defined")

idea/testData/refactoring/introduceTypeAlias/typeConstructor.kt

@@ -0,0 +1,10 @@
+// NAME: S
+
+class A<X, Y>
+
+class B<T>
+
+// SIBLING:
+fun foo(a: <selection>A</selection><(Int) -> B<Int>, B<String>?>) {
+
+}

idea/testData/refactoring/introduceTypeAlias/typeConstructor.kt.after

@@ -0,0 +1,12 @@
+// NAME: S
+
+class A<X, Y>
+
+class B<T>
+
+typealias S<T, U> = A<T, U>
+
+// SIBLING:
+fun foo(a: S<(Int) -> B<Int>, B<String>?>) {
+
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/introduce/ExtractionTestGenerated.java

@@ -4084,6 +4084,12 @@ public class ExtractionTestGenerated extends AbstractExtractionTest {
             doIntroduceTypeAliasTest(fileName);
         }
 
+        @TestMetadata("typeConstructor.kt")
+        public void testTypeConstructor() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceTypeAlias/typeConstructor.kt");
+            doIntroduceTypeAliasTest(fileName);
+        }
+
         @TestMetadata("typesExtractedWithFunctionalType.kt")
         public void testTypesExtractedWithFunctionalType() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/introduceTypeAlias/typesExtractedWithFunctionalType.kt");