Fixed ShortenReferences for the case of extension for object

idea/idea-core/src/org/jetbrains/kotlin/idea/core/ShortenReferences.kt

@@ -444,8 +444,7 @@ class ShortenReferences(val options: (KtElement) -> Options = { Options.DEFAULT
             element: KtDotQualifiedExpression,
             bindingContext: BindingContext
         ): AnalyzeQualifiedElementResult {
-            val receiver = element.receiverExpression
-            if (receiver !is KtThisExpression && bindingContext[BindingContext.QUALIFIER, receiver] == null) return AnalyzeQualifiedElementResult.Skip
+            if (!canBePossibleToDropReceiver(element, bindingContext)) return AnalyzeQualifiedElementResult.Skip
 
             if (PsiTreeUtil.getParentOfType(
                     element,
@@ -503,6 +502,7 @@ class ShortenReferences(val options: (KtElement) -> Options = { Options.DEFAULT
             }
 
 
+            val receiver = element.receiverExpression
             if (receiver is KtThisExpression) {
                 if (!targetsMatch) return AnalyzeQualifiedElementResult.Skip
                 val originalCall = selector.getResolvedCall(bindingContext) ?: return AnalyzeQualifiedElementResult.Skip
@@ -536,6 +536,17 @@ class ShortenReferences(val options: (KtElement) -> Options = { Options.DEFAULT
             }
         }
 
+        private fun canBePossibleToDropReceiver(element: KtDotQualifiedExpression, bindingContext: BindingContext): Boolean {
+            val receiver = element.receiverExpression
+            if (receiver is KtThisExpression) return true
+            val qualifier = bindingContext[BindingContext.QUALIFIER, receiver] ?: return false
+            val classDescriptor = qualifier.descriptor as? ClassDescriptor ?: return true
+            if (classDescriptor.kind != ClassKind.OBJECT) return true
+            // for object receiver we should additionally check that it's dispatch receiver (that is the member is inside the object)
+            val resolvedCall = element.getResolvedCall(bindingContext) ?: return false
+            return resolvedCall.explicitReceiverKind == ExplicitReceiverKind.DISPATCH_RECEIVER
+        }
+
         private fun copyShortenAndAnalyze(
             element: KtDotQualifiedExpression,
             bindingContext: BindingContext

idea/testData/shortenRefs/extensionForObject.dependency.kt

@@ -0,0 +1,5 @@
+package dependency
+
+object AnObject
+
+fun AnObject.extFun(){}

idea/testData/shortenRefs/extensionForObject.kt

@@ -0,0 +1,5 @@
+import dependency.extFun
+
+fun foo() {
+    <selection>dependency.AnObject.extFun()</selection>
+}

idea/testData/shortenRefs/extensionForObject.kt.after

@@ -0,0 +1,6 @@
+import dependency.AnObject
+import dependency.extFun
+
+fun foo() {
+    AnObject.extFun()
+}

idea/tests/org/jetbrains/kotlin/shortenRefs/ShortenRefsTestGenerated.java

@@ -59,6 +59,12 @@ public class ShortenRefsTestGenerated extends AbstractShortenRefsTest {
         runTest("idea/testData/shortenRefs/descriptorsChangeAfterImportInsertion.kt");
     }
 
+    @TestMetadata("extensionForObject.kt")
+    public void testExtensionForObject() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/shortenRefs/extensionForObject.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("extensionFunctionVarInvokedWithQualifier.kt")
     public void testExtensionFunctionVarInvokedWithQualifier() throws Exception {
         runTest("idea/testData/shortenRefs/extensionFunctionVarInvokedWithQualifier.kt");