Fix false positive "Redundant companion reference"

#KT-30166 Fixed

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

@@ -12,8 +12,7 @@ import com.intellij.codeInspection.ProblemsHolder
 import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiElementVisitor
 import org.jetbrains.kotlin.descriptors.*
-import org.jetbrains.kotlin.idea.caches.resolve.resolveToCall
+import org.jetbrains.kotlin.idea.caches.resolve.analyze
-import org.jetbrains.kotlin.idea.intentions.getCallableDescriptor
 import org.jetbrains.kotlin.idea.references.mainReference
 import org.jetbrains.kotlin.idea.search.usagesSearch.descriptor
 import org.jetbrains.kotlin.idea.util.getResolutionScope
@@ -21,7 +20,10 @@ import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.containingClass
+import org.jetbrains.kotlin.psi.psiUtil.getQualifiedElementSelector
+import org.jetbrains.kotlin.psi.psiUtil.getReceiverExpression
 import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
+import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.resolve.calls.util.FakeCallableDescriptorForObject
 import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassNotAny
 import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperInterfaces
@@ -40,10 +42,12 @@ class RedundantCompanionReferenceInspection : AbstractKotlinInspection() {
             if (!objectDeclaration.isCompanion()) return
             if (expression.text != objectDeclaration.name) return
 
+            val context = expression.analyze()
+
             val containingClass = objectDeclaration.containingClass() ?: return
             if (expression.containingClass() != containingClass && expression == parent.receiverExpression) return
             val containingClassDescriptor = containingClass.descriptor as? ClassDescriptor ?: return
-            val selectorDescriptor = selectorExpression?.getCallableDescriptor()
+            val selectorDescriptor = selectorExpression?.getResolvedCall(context)?.resultingDescriptor
             when (selectorDescriptor) {
                 is PropertyDescriptor -> {
                     val name = selectorDescriptor.name
@@ -59,9 +63,13 @@ class RedundantCompanionReferenceInspection : AbstractKotlinInspection() {
                 }
             }
 
+            (expression as? KtSimpleNameExpression)?.getReceiverExpression()?.getQualifiedElementSelector()
+                ?.mainReference?.resolveToDescriptors(context)?.firstOrNull()
+                ?.let { if (it != containingClassDescriptor) return }
+
             val grandParent = parent.parent as? KtQualifiedExpression
             if (grandParent != null) {
-                val grandParentDescriptor = grandParent.resolveToCall()?.resultingDescriptor ?: return
+                val grandParentDescriptor = grandParent.getResolvedCall(context)?.resultingDescriptor ?: return
                 if (grandParentDescriptor is ConstructorDescriptor || grandParentDescriptor is FakeCallableDescriptorForObject) return
             }
 

idea/testData/inspectionsLocal/redundantCompanionReference/notApplicableCollision.kt

@@ -0,0 +1,12 @@
+// PROBLEM: none
+package my.sample
+
+class Class {
+    companion object Class {
+        fun say() {}
+    }
+}
+
+fun test() {
+    Class<caret>.say()
+}

idea/testData/inspectionsLocal/redundantCompanionReference/notApplicableCollision2.kt

@@ -0,0 +1,14 @@
+// PROBLEM: none
+package my.sample
+
+class Outer {
+    class Class {
+        companion object Class {
+            fun say() {}
+        }
+    }
+}
+
+fun test() {
+    Outer.Class<caret>.say()
+}

idea/testData/inspectionsLocal/redundantCompanionReference/notApplicablePackage.kt

@@ -0,0 +1,12 @@
+// PROBLEM: none
+package my.sample
+
+class Class {
+    fun test() {
+        my.sample.Class<caret>.say()
+    }
+
+    companion object Class {
+        fun say() {}
+    }
+}

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

@@ -4662,6 +4662,21 @@ public class LocalInspectionTestGenerated extends AbstractLocalInspectionTest {
             runTest("idea/testData/inspectionsLocal/redundantCompanionReference/named.kt");
         }
 
+        @TestMetadata("notApplicableCollision.kt")
+        public void testNotApplicableCollision() throws Exception {
+            runTest("idea/testData/inspectionsLocal/redundantCompanionReference/notApplicableCollision.kt");
+        }
+
+        @TestMetadata("notApplicableCollision2.kt")
+        public void testNotApplicableCollision2() throws Exception {
+            runTest("idea/testData/inspectionsLocal/redundantCompanionReference/notApplicableCollision2.kt");
+        }
+
+        @TestMetadata("notApplicablePackage.kt")
+        public void testNotApplicablePackage() throws Exception {
+            runTest("idea/testData/inspectionsLocal/redundantCompanionReference/notApplicablePackage.kt");
+        }
+
         @TestMetadata("notCompanion.kt")
         public void testNotCompanion() throws Exception {
             runTest("idea/testData/inspectionsLocal/redundantCompanionReference/notCompanion.kt");