KT-33903: consider imports from objects when removing descriptors duplicates

- `ImportedFromObjectCallableDescriptor` and descriptors in general do
not have consistent `equals`,  which leads to duplication in completion
when multiple functions from objects are imported, or when function is
visible in some scope both implicitly and by import (see KT33903_1.kt)
- ^KT-33903 Fixed

idea/idea-completion/src/org/jetbrains/kotlin/idea/completion/LookupElementsCollector.kt

@@ -28,6 +28,7 @@ import org.jetbrains.kotlin.descriptors.MemberDescriptor
 import org.jetbrains.kotlin.idea.completion.handlers.WithExpressionPrefixInsertHandler
 import org.jetbrains.kotlin.idea.completion.handlers.WithTailInsertHandler
 import org.jetbrains.kotlin.idea.core.completion.DeclarationLookupObject
+import org.jetbrains.kotlin.resolve.ImportedFromObjectCallableDescriptor
 import java.util.*
 import kotlin.math.max
 
@@ -90,7 +91,7 @@ class LookupElementsCollector(
         withReceiverCast: Boolean = false,
         prohibitDuplicates: Boolean = false
     ) {
-        if (prohibitDuplicates && descriptor is CallableDescriptor && descriptor in processedCallables) return
+        if (prohibitDuplicates && descriptor is CallableDescriptor && unwrapIfImportedFromObject(descriptor) in processedCallables) return
 
         var lookupElements = lookupElementFactory.createStandardLookupElementsForDescriptor(descriptor, useReceiverTypes = true)
 
@@ -100,7 +101,7 @@ class LookupElementsCollector(
 
         addElements(lookupElements, notImported)
 
-        if (prohibitDuplicates && descriptor is CallableDescriptor) processedCallables.add(descriptor)
+        if (prohibitDuplicates && descriptor is CallableDescriptor) processedCallables.add(unwrapIfImportedFromObject(descriptor))
     }
 
     fun addElement(element: LookupElement, notImported: Boolean = false) {
@@ -176,3 +177,6 @@ class LookupElementsCollector(
         resultSet.restartCompletionOnPrefixChange(prefixCondition)
     }
 }
+
+private fun unwrapIfImportedFromObject(descriptor: CallableDescriptor): CallableDescriptor =
+    if (descriptor is ImportedFromObjectCallableDescriptor<*>) descriptor.callableFromObject else descriptor

idea/idea-completion/testData/basic/common/KT33903_1.kt

@@ -0,0 +1,13 @@
+import Obj.foo
+import Obj.foo
+
+object Obj {
+    fun Any.foo() {}
+
+    fun usage() {
+        Any().foo<caret>
+    }
+}
+
+// EXIST: foo
+// NUMBER: 1

idea/idea-completion/testData/basic/common/KT33903_2.kt

@@ -0,0 +1,13 @@
+import Obj.foo
+import Obj.foo
+
+object Obj {
+    fun Any.foo() {}
+}
+
+fun usage() {
+    Any().foo<caret>
+}
+
+// EXIST: foo
+// NUMBER: 1

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JSBasicCompletionTestGenerated.java

@@ -441,6 +441,16 @@ public class JSBasicCompletionTestGenerated extends AbstractJSBasicCompletionTes
             runTest("idea/idea-completion/testData/basic/common/KT13780_1.kt");
         }
 
+        @TestMetadata("KT33903_1.kt")
+        public void testKT33903_1() throws Exception {
+            runTest("idea/idea-completion/testData/basic/common/KT33903_1.kt");
+        }
+
+        @TestMetadata("KT33903_2.kt")
+        public void testKT33903_2() throws Exception {
+            runTest("idea/idea-completion/testData/basic/common/KT33903_2.kt");
+        }
+
         @TestMetadata("LocalMultideclarationValues.kt")
         public void testLocalMultideclarationValues() throws Exception {
             runTest("idea/idea-completion/testData/basic/common/LocalMultideclarationValues.kt");

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JvmBasicCompletionTestGenerated.java

@@ -441,6 +441,16 @@ public class JvmBasicCompletionTestGenerated extends AbstractJvmBasicCompletionT
             runTest("idea/idea-completion/testData/basic/common/KT13780_1.kt");
         }
 
+        @TestMetadata("KT33903_1.kt")
+        public void testKT33903_1() throws Exception {
+            runTest("idea/idea-completion/testData/basic/common/KT33903_1.kt");
+        }
+
+        @TestMetadata("KT33903_2.kt")
+        public void testKT33903_2() throws Exception {
+            runTest("idea/idea-completion/testData/basic/common/KT33903_2.kt");
+        }
+
         @TestMetadata("LocalMultideclarationValues.kt")
         public void testLocalMultideclarationValues() throws Exception {
             runTest("idea/idea-completion/testData/basic/common/LocalMultideclarationValues.kt");