Refactor sealed subclass to object: add tests, fix type parameter case

idea/src/org/jetbrains/kotlin/idea/inspections/CanSealedSubClassBeObjectInspection.kt

@@ -38,6 +38,7 @@ class CanSealedSubClassBeObjectInspection : AbstractKotlinInspection() {
                 klass.getSubclasses()
                     .withEmptyConstructors()
                     .thatAreFinal()
+                    .thatHasNoTypeParameters()
                     .thatHasNoInnerClasses()
                     .thatHasNoCompanionObjects()
                     .forEach { reportPossibleObject(it) }
@@ -74,6 +75,10 @@ class CanSealedSubClassBeObjectInspection : AbstractKotlinInspection() {
         return filter { klass -> klass.getModalityFromDescriptor() == KtTokens.FINAL_KEYWORD }
     }
 
+    private fun List<KtClass>.thatHasNoTypeParameters(): List<KtClass> {
+        return filter { klass -> klass.typeParameters.isEmpty() }
+    }
+
     private fun List<KtClass>.thatHasNoInnerClasses(): List<KtClass> {
         return filter { klass -> klass.hasNoInnerClass() }
     }

idea/testData/inspectionsLocal/convertSealedSubClassToObject/generic.kt

@@ -0,0 +1,5 @@
+// PROBLEM: none
+
+sealed class Sealed<T>
+
+<caret>class SubSealed<T> : Sealed<T>()

idea/testData/inspectionsLocal/convertSealedSubClassToObject/nonEmptyConstructor.kt

@@ -0,0 +1,5 @@
+// PROBLEM: none
+
+sealed class Sealed(val y: Int)
+
+<caret>class SubSealed(x: Int) : Sealed(x)

idea/testData/inspectionsLocal/convertSealedSubClassToObject/openSubclass.kt

@@ -0,0 +1,5 @@
+// PROBLEM: none
+
+sealed class Sealed
+
+open <caret>class SubSealed : Sealed()

idea/testData/inspectionsLocal/convertSealedSubClassToObject/withCompanion.kt

@@ -0,0 +1,9 @@
+// PROBLEM: none
+
+sealed class Sealed
+
+<caret>class SubSealed : Sealed() {
+    companion object {
+
+    }
+}

idea/testData/inspectionsLocal/convertSealedSubClassToObject/withInner.kt

@@ -0,0 +1,11 @@
+// PROBLEM: none
+
+sealed class Sealed
+
+<caret>class SubSealed : Sealed() {
+    val x: Int = 42
+
+    inner class Inner {
+        fun foo() = x
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java

@@ -1259,6 +1259,36 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/convertSealedSubClassToObject/convertSubClassWithoutParentheses.kt");
             doTest(fileName);
         }
+
+        @TestMetadata("generic.kt")
+        public void testGeneric() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/convertSealedSubClassToObject/generic.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("nonEmptyConstructor.kt")
+        public void testNonEmptyConstructor() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/convertSealedSubClassToObject/nonEmptyConstructor.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("openSubclass.kt")
+        public void testOpenSubclass() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/convertSealedSubClassToObject/openSubclass.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("withCompanion.kt")
+        public void testWithCompanion() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/convertSealedSubClassToObject/withCompanion.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("withInner.kt")
+        public void testWithInner() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/inspectionsLocal/convertSealedSubClassToObject/withInner.kt");
+            doTest(fileName);
+        }
     }
 
     @TestMetadata("idea/testData/inspectionsLocal/copyWithoutNamedArguments")