Fix KNPE in "Move member to companion" for expect class #KT-28383 Fixed

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

@@ -161,11 +161,11 @@ class MoveMemberToCompanionObjectIntention : SelfTargetingRangeIntention<KtNamed
         val javaCodeStyleManager = JavaCodeStyleManager.getInstance(project)
 
         val companionObject = containingClass.getOrCreateCompanionObject()
-        val companionLightClass = companionObject.toLightClass()!!
+        val companionLightClass = companionObject.toLightClass()
 
         val ktPsiFactory = KtPsiFactory(project)
         val javaPsiFactory = JavaPsiFacade.getInstance(project).elementFactory
-        val javaCompanionRef = javaPsiFactory.createReferenceExpression(companionLightClass)
+        val javaCompanionRef = companionLightClass?.let { javaPsiFactory.createReferenceExpression(it) }
         val ktCompanionRef = ktPsiFactory.createExpression(companionObject.fqName!!.asString())
 
         val elementsToShorten = SmartList<KtElement>()
@@ -217,10 +217,12 @@ class MoveMemberToCompanionObjectIntention : SelfTargetingRangeIntention<KtNamed
 
             when (usage) {
                 is JavaUsageInfo -> {
-                    (usageElement as? PsiReferenceExpression)
+                    if (javaCompanionRef != null) {
+                        (usageElement as? PsiReferenceExpression)
                             ?.qualifierExpression
                             ?.replace(javaCompanionRef)
                             ?.let { javaCodeStyleManager.shortenClassReferences(it) }
+                    }
                 }
 
                 is ExplicitReceiverUsageInfo -> {

idea/testData/intentions/moveToCompanion/expectClass.kt

@@ -0,0 +1,5 @@
+// ERROR: The feature "multi platform projects" is experimental and should be enabled explicitly
+
+expect class Some {
+    val <caret>x: Int
+}

idea/testData/intentions/moveToCompanion/expectClass.kt.after

@@ -0,0 +1,7 @@
+// ERROR: The feature "multi platform projects" is experimental and should be enabled explicitly
+
+expect class Some {
+    companion object {
+        val x: Int
+    }
+}

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

@@ -12133,6 +12133,11 @@ public class IntentionTestGenerated extends AbstractIntentionTest {
             runTest("idea/testData/intentions/moveToCompanion/enumEntry.kt");
         }
 
+        @TestMetadata("expectClass.kt")
+        public void testExpectClass() throws Exception {
+            runTest("idea/testData/intentions/moveToCompanion/expectClass.kt");
+        }
+
         @TestMetadata("functionWithOverride.kt")
         public void testFunctionWithOverride() throws Exception {
             runTest("idea/testData/intentions/moveToCompanion/functionWithOverride.kt");