Expect/actual companion object: set gutter on leaf element

May fix KT-21113

idea/src/org/jetbrains/kotlin/idea/highlighter/markers/KotlinLineMarkerProvider.kt

@@ -333,11 +333,11 @@ private fun collectOverriddenPropertyAccessors(
 
 private val KtNamedDeclaration.expectOrActualAnchor
     get() =
-        nameIdentifier
-                ?: (this as? KtConstructor<*>)?.let {
-                    it.getConstructorKeyword() ?: it.getValueParameterList()?.leftParenthesis
-                }
-                ?: this
+        nameIdentifier ?: when (this) {
+            is KtConstructor<*> -> getConstructorKeyword() ?: getValueParameterList()?.leftParenthesis
+            is KtObjectDeclaration -> getObjectKeyword()
+            else -> null
+        } ?: this
 
 private fun collectActualMarkers(
     declaration: KtNamedDeclaration,

idea/src/org/jetbrains/kotlin/idea/highlighter/markers/KotlinLineMarkerProvider.kt.172

@@ -331,11 +331,11 @@ private fun collectOverriddenPropertyAccessors(
 
 private val KtNamedDeclaration.expectOrActualAnchor
     get() =
-        nameIdentifier
-                ?: (this as? KtConstructor<*>)?.let {
-                    it.getConstructorKeyword() ?: it.getValueParameterList()?.leftParenthesis
-                }
-                ?: this
+        nameIdentifier ?: when (this) {
+            is KtConstructor<*> -> getConstructorKeyword() ?: getValueParameterList()?.leftParenthesis
+            is KtObjectDeclaration -> getObjectKeyword()
+            else -> null
+        } ?: this
 
 private fun collectActualMarkers(
     declaration: KtNamedDeclaration,

idea/testData/multiModuleLineMarker/fromActualCompanion/common/common.kt

@@ -0,0 +1,7 @@
+// !CHECK_HIGHLIGHTING
+
+expect class WithCompanion {
+    companion object {
+
+    }
+}

idea/testData/multiModuleLineMarker/fromActualCompanion/jvm/jvm.kt

@@ -0,0 +1,5 @@
+actual class <lineMarker>WithCompanion</lineMarker> {
+    actual companion <lineMarker>object</lineMarker> {
+
+    }
+}

idea/testData/multiModuleLineMarker/fromExpectCompanion/common/common.kt

@@ -0,0 +1,5 @@
+expect class <lineMarker>WithCompanion</lineMarker> {
+    companion <lineMarker>object</lineMarker> {
+
+    }
+}

idea/testData/multiModuleLineMarker/fromExpectCompanion/jvm/jvm.kt

@@ -0,0 +1,7 @@
+// !CHECK_HIGHLIGHTING
+
+actual class WithCompanion {
+    actual companion object {
+
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/caches/resolve/MultiModuleLineMarkerTestGenerated.java

@@ -44,6 +44,11 @@ public class MultiModuleLineMarkerTestGenerated extends AbstractMultiModuleLineM
         runTest("idea/testData/multiModuleLineMarker/fromActualAnnotation/");
     }
 
+    @TestMetadata("fromActualCompanion")
+    public void testFromActualCompanion() throws Exception {
+        runTest("idea/testData/multiModuleLineMarker/fromActualCompanion/");
+    }
+
     @TestMetadata("fromActualPrimaryConstructor")
     public void testFromActualPrimaryConstructor() throws Exception {
         runTest("idea/testData/multiModuleLineMarker/fromActualPrimaryConstructor/");
@@ -84,6 +89,11 @@ public class MultiModuleLineMarkerTestGenerated extends AbstractMultiModuleLineM
         runTest("idea/testData/multiModuleLineMarker/fromCommonToJvmImpl/");
     }
 
+    @TestMetadata("fromExpectCompanion")
+    public void testFromExpectCompanion() throws Exception {
+        runTest("idea/testData/multiModuleLineMarker/fromExpectCompanion/");
+    }
+
     @TestMetadata("fromExpectedAnnotation")
     public void testFromExpectedAnnotation() throws Exception {
         runTest("idea/testData/multiModuleLineMarker/fromExpectedAnnotation/");