Move to Companion Object: Forbid for functions/properties referencing type parameters of the containing class

#KT-13876 Fixed

ChangeLog.md

@@ -114,6 +114,7 @@ These artifacts include extensions for the types available in the latter JDKs, s
 - [`KT-11483`](https://youtrack.jetbrains.com/issue/KT-11483) Move to Companion: Do not use qualified names as labels
 - [`KT-13874`](https://youtrack.jetbrains.com/issue/KT-13874) Move to Companion: Fix AssertionError on running refactoring from Conflicts View
 - [`KT-13883`](https://youtrack.jetbrains.com/issue/KT-13883) Move to Companion Object: Fix exception when applied to class
+- [`KT-13876`](https://youtrack.jetbrains.com/issue/KT-13876) Move to Companion Object: Forbid for functions/properties referencing type parameters of the containing class
 
 ##### New features
 

idea/src/org/jetbrains/kotlin/idea/intentions/MoveMemberToCompanionObjectIntention.kt

@@ -36,12 +36,10 @@ import com.intellij.util.containers.MultiMap
 import org.jetbrains.kotlin.asJava.toLightClass
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.ClassDescriptorWithResolutionScopes
+import org.jetbrains.kotlin.descriptors.TypeParameterDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.caches.resolve.resolveToDescriptor
-import org.jetbrains.kotlin.idea.core.CollectingNameValidator
-import org.jetbrains.kotlin.idea.core.KotlinNameSuggester
-import org.jetbrains.kotlin.idea.core.getOrCreateCompanionObject
-import org.jetbrains.kotlin.idea.core.replaced
+import org.jetbrains.kotlin.idea.core.*
 import org.jetbrains.kotlin.idea.refactoring.checkConflictsInteractively
 import org.jetbrains.kotlin.idea.refactoring.move.OuterInstanceReferenceUsageInfo
 import org.jetbrains.kotlin.idea.refactoring.move.collectOuterInstanceReferences
@@ -53,7 +51,6 @@ import org.jetbrains.kotlin.idea.references.KtSimpleNameReference
 import org.jetbrains.kotlin.idea.search.declarationsSearch.HierarchySearchRequest
 import org.jetbrains.kotlin.idea.search.declarationsSearch.searchOverriders
 import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
-import org.jetbrains.kotlin.idea.core.ShortenReferences
 import org.jetbrains.kotlin.idea.util.application.runReadAction
 import org.jetbrains.kotlin.idea.util.application.runWriteAction
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
@@ -62,6 +59,7 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.*
+import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 import org.jetbrains.kotlin.resolve.scopes.receivers.ExpressionReceiver
@@ -237,6 +235,14 @@ class MoveMemberToCompanionObjectIntention : SelfTargetingRangeIntention<KtNamed
         runTemplateForInstanceParam(newDeclaration, nameSuggestions, editor)
     }
 
+    private fun hasTypeParameterReferences(containingClass: KtClassOrObject, element: KtNamedDeclaration): Boolean {
+        val containingClassDescriptor = containingClass.resolveToDescriptor()
+        return element.collectDescendantsOfType<KtTypeReference> {
+            val referencedDescriptor = it.analyze(BodyResolveMode.PARTIAL)[BindingContext.TYPE, it]?.constructor?.declarationDescriptor
+            referencedDescriptor is TypeParameterDescriptor && referencedDescriptor.containingDeclaration == containingClassDescriptor
+        }.isNotEmpty()
+    }
+
     override fun startInWriteAction() = false
 
     override fun applyTo(element: KtNamedDeclaration, editor: Editor?) {
@@ -259,10 +265,14 @@ class MoveMemberToCompanionObjectIntention : SelfTargetingRangeIntention<KtNamed
             return
         }
 
+        val description = RefactoringUIUtil.getDescription(element, false).capitalize()
+
         if (HierarchySearchRequest(element, element.useScope, false).searchOverriders().any()) {
-            val description = RefactoringUIUtil.getDescription(element, false).capitalize()
-            CommonRefactoringUtil.showErrorHint(project, editor, "$description is overridden by declaration(s) in a subclass", text, null)
-            return
+            return CommonRefactoringUtil.showErrorHint(project, editor, "$description is overridden by declaration(s) in a subclass", text, null)
+        }
+
+        if (hasTypeParameterReferences(element.containingClassOrObject!!, element)) {
+            return CommonRefactoringUtil.showErrorHint(project, editor, "$description references type parameters of the containing class", text, null)
         }
 
         val externalUsages = SmartList<UsageInfo>()

idea/testData/intentions/moveToCompanion/genericFunction.kt

@@ -0,0 +1,4 @@
+// SHOULD_FAIL_WITH: Function <b><code>genericFunT()</code></b> references type parameters of the containing class
+class Test6<T>(val t: T) {
+    fun <caret>genericFunT(): T = t
+}

idea/testData/intentions/moveToCompanion/genericProperty.kt

@@ -0,0 +1,4 @@
+// SHOULD_FAIL_WITH: Property <b><code>genericValT</code></b> references type parameters of the containing class
+class Test6<T>(val t: T) {
+    val <caret>genericValT: T get() = t
+}

idea/tests/org/jetbrains/kotlin/idea/intentions/IntentionTestGenerated.java

@@ -9067,6 +9067,18 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             doTest(fileName);
         }
 
+        @TestMetadata("genericFunction.kt")
+        public void testGenericFunction() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/moveToCompanion/genericFunction.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("genericProperty.kt")
+        public void testGenericProperty() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/moveToCompanion/genericProperty.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("implicitDispatchReceiver.kt")
         public void testImplicitDispatchReceiver() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/intentions/moveToCompanion/implicitDispatchReceiver.kt");